2024-03-28T18:15:21Zhttps://vtechworks.lib.vt.edu/server/oai/requestoai:vtechworks.lib.vt.edu:10919/792342021-10-08T16:43:28Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78882col_10919_23748
Why Don’t More Farmers Go Organic? Using A Stakeholder-Informed Exploratory Agent-Based Model to Represent the Dynamics of Farming Practices in the Philippines
Olabisi, Laura Schmitt
Wang, Ryan Qi
Ligmann-Zielinska, Arika
Civil and Environmental Engineering
organic agriculture
agent-based modeling
sensitivity analysis
social networks
Philippines
In spite of a growing interest in organic agriculture; there has been relatively little research on why farmers might choose to adopt organic methods, particularly in the developing world. To address this shortcoming, we developed an exploratory agent-based model depicting Philippine smallholder farmer decisions to implement organic techniques in rice paddy systems. Our modeling exercise was novel in its combination of three characteristics: first, agent rules were based on focus group data collected in the system of study. Second, a social network structure was built into the model. Third, we utilized variance-based sensitivity analysis to quantify model outcome variability, identify influential drivers, and suggest ways in which further modeling efforts could be focused and simplified. The model results indicated an upper limit on the number of farmers adopting organic methods. The speed of information spread through the social network; crop yields; and the size of a farmer’s plot were highly influential in determining agents’ adoption rates. The results of this stylized model indicate that rates of organic farming adoption are highly sensitive to the yield drop after switchover to organic techniques, and to the speed of information spread through existing social networks. Further research and model development should focus on these system characteristics.
2017-09-20T18:21:49Z
2017-09-20T18:21:49Z
2015-10-22
2017-09-20T18:21:49Z
Article - Refereed
Olabisi, L.S.; Wang, R.Q.; Ligmann-Zielinska, A. Why Don’t More Farmers Go Organic? Using A Stakeholder-Informed Exploratory Agent-Based Model to Represent the Dynamics of Farming Practices in the Philippines. Land 2015, 4, 979-1002.
http://hdl.handle.net/10919/79234
https://doi.org/10.3390/land4040979
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Philippines
MDPI
oai:vtechworks.lib.vt.edu:10919/750282023-11-29T15:28:04Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539com_10919_72294col_10919_70873col_10919_23748col_10919_72295
Osmotic bioelectrochemical systems
He, Zhen
Civil and Environmental Engineering
A bioelectrochemical system includes an anode, a saline solution chamber, and a cathode. The anode is at least partially positioned within an anode chamber containing an aqueous reaction mixture including one or more organic compounds and one or more bacteria for oxidizing the organic compounds. The saline solution chamber contains a draw solution and is separated from the anode chamber by a forward osmosis membrane. Water diffuses across the forward osmosis membrane from the aqueous reaction mixture to the draw solution.
2017-02-14T20:45:56Z
2017-02-14T20:45:56Z
2013-01-17
2012-07-11
Patent
http://hdl.handle.net/10919/75028
9,527,038
en
oai:vtechworks.lib.vt.edu:10919/959972023-11-29T19:06:43Zcom_10919_5540com_10919_24214com_10919_5539com_10919_23747com_10919_51731com_10919_5478com_10919_79468com_10919_78628col_10919_71752col_10919_24288col_10919_23748col_10919_51732col_10919_79481
Mitigation of bidirectional solute flux in forward osmosis via membrane surface coating of zwitterion functionalized carbon nanotubes
Zou, Shiqiang
Smith, Ethan D.
Lin, Shihong
Martin, Stephen M.
He, Zhen
Civil and Environmental Engineering
Chemical Engineering
Macromolecules Innovation Institute
Forward osmosis
Reverse solute flux
Forward solute flux
Zwitterion
Membrane modification
Forward osmosis (FO) has emerged as a promising membrane technology to yield high-quality reusable water from various water sources. A key challenge to be solved is the bidirectional solute flux (BSF), including reverse solute flux (RSF) and forward solute flux (FSF). Herein, zwitterion functionalized carbon nanotubes (Z-CNTs) have been coated onto a commercial thin film composite (TFC) membrane, resulting in BSF mitigation via both electrostatic repulsion forces induced by zwitterionic functional groups and steric interactions with CNTs. At a coating density of 0.97 gm⁻², a significantly reduced specific RSF was observed for multiple draw solutes, including NaCl (55.5% reduction), NH₄H₂PO₄(83.8%), (NH₄)₂HPO₄ (74.5%), NH₄Cl (70.8%), and NH₄HCO₃ (61.9%). When a synthetic wastewater was applied as the feed to investigate membrane rejection, FSF was notably reduced by using the coated membrane with fewer pollutants leaked to the draw solution, including NH₄⁺-N (46.3% reduction), NO₂⁻₋N (37.0%), NO₂⁻₋N (30.3%), K⁺ (56.1%), PO₄³⁻₋P (100%), and Mg²⁺ (100%). When fed with real wastewater, a consistent water flux was achieved during semi-continuous operation with enhanced fouling resistance. This study is among the earliest efforts to address BSF control via membrane modification, and the results will encourage further exploration of effective strategies to reduce BSF.
2019-12-16T13:58:25Z
2019-12-16T13:58:25Z
2019-07-08
Article
http://hdl.handle.net/10919/95997
https://doi.org/10.1016/j.envint.2019.104970
131
en
http://creativecommons.org/licenses/by-nc-nd/3.0/us/
Creative Commons Attribution-NonCommercial-NoDerivs 3.0 United States
Elsevier
oai:vtechworks.lib.vt.edu:10919/849832023-11-29T19:06:45Zcom_10919_8195com_10919_25799com_10919_5540com_10919_23747com_10919_5539col_10919_78797col_10919_71752col_10919_23748
The State-of-the-Art Review on Molecular Dynamics Simulation of Asphalt Binder
Qu, Xin
Wang, Dawei
Wang, Linbing
Huang, Yucheng
Hou, Yue
Oeser, Markus
Civil and Environmental Engineering
Asphalt pavement has been widely used in the world. As the main components of asphalt pavement, the asphalt binder is crucial to the service performance and life of the road. In the past decades, numerous studies were conducted on technical performance, aging, and modification of the asphalt binder. With the development of modern technology, it was discovered that the microscopic properties, aging mechanism, and modification mechanism of the asphalt binder affect the macroscopic performance of asphalt pavement significantly. As a new emerging powerful numerical tool, the molecular dynamics (MD) simulation has been developed to study the asphalt binder material from a micro perspective. Based on the previous studies, some average asphalt binder models, fractional asphalt binder models, aged asphalt binder models, and modifier models were proposed by many researchers, which have made remarkable progress in asphalt studies; the microproperties, aging mechanism, and modification mechanism of the asphalt binder can also be analyzed using the MD simulation. Overall, the state-of-the-art review provides a comprehensive view for the readers to better understand the development, establishment, and application of the asphalt molecular model.
2018-09-10T12:54:03Z
2018-09-10T12:54:03Z
2018-09-03
2018-09-09T07:04:45Z
Article - Refereed
Xin Qu, Dawei Wang, Linbing Wang, Yucheng Huang, Yue Hou, and Markus Oeser, “The State-of-the-Art Review on Molecular Dynamics Simulation of Asphalt Binder,” Advances in Civil Engineering, vol. 2018, Article ID 4546191, 14 pages, 2018. doi:10.1155/2018/4546191
http://hdl.handle.net/10919/84983
https://doi.org/10.1155/2018/4546191
en
http://creativecommons.org/licenses/by/4.0/
Copyright © 2018 Xin Qu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Creative Commons Attribution 4.0 International
Hindawi
oai:vtechworks.lib.vt.edu:10919/1166392023-11-08T08:14:06Zcom_10919_23747com_10919_5539col_10919_23748
Alleviating Water Scarcity by Optimizing Crop Mixes
Richter, Brian D.
Ao, Yufei
Lamsal, Gambhir
Wei, Dongyang
Amaya, Maria
Marston, Landon T.
Davis, Kyle F.
Water scarcity
Crop mixes
Irrigated agriculture dominates freshwater consumption globally, but crop production and farm revenues suffer when water supplies are insufficient to meet irrigation needs. In the United States, the mismatch between irrigation demand and freshwater availability has been exacerbated in recent decades due to recurrent droughts, climate change and over extraction that dries rivers and depletes aquifers. Yet, there has been no spatially detailed assessment of the potential for shifting to new crop mixes to reduce crop water demands and alleviate water shortage risks. In this study, we combined modelled crop water requirements and detailed agricultural statistics within a national hydrological model to quantify sub-basin-level river depletion, finding high-to-severe levels of irrigation scarcity in 30% of sub-basins in the western United States, with cattle-feed crops—alfalfa and other hay—being the largest water consumers in 57% of the region’s sub-basins. We also assessed recent trends in irrigation water consumption, crop production and revenue generation in six high-profile farming areas and found that in recent decades, water consumption has decreased in four of our study areas—a result of a reduction in the irrigated area and shifts in the production of the most water-consumptive crops—even while farm revenues increased. To examine the opportunities for crop shifting and fallowing to realize further reductions in water consumption, we performed optimizations on realistic scenarios for modifying crop mixes while sustaining or improving net farm profits, finding that additional water savings of 28–57% are possible across our study areas. These findings demonstrate strong opportunities for economic, food security and environmental co-benefits in irrigated agriculture and provide both hope and direction to regions struggling with water scarcity around the world.
2023-11-07T12:57:13Z
2023-11-07T12:57:13Z
2023-11
Article - Refereed
http://hdl.handle.net/10919/116639
https://doi.org/10.1038/s44221-023-00155-9
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Nature Portfolio
oai:vtechworks.lib.vt.edu:10919/979292021-10-08T16:43:28Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78882col_10919_23748
Improved Homotopy Perturbation Method for Geometrically Nonlinear Analysis of Space Trusses
Dehghani, Hamzeh
Mansouri, Iman
Farzampour, Alireza
Hu, Jong Wan
Civil and Environmental Engineering
homotopy
nonlinear analysis
Newton–Raphson method
space-trusses
The objective of this study is to explore a noble application of the improved homotopy perturbation procedure bases in structural engineering by applying it to the geometrically nonlinear analysis of the space trusses. The improved perturbation algorithm is proposed to refine the classical methods in numerical computing techniques such as the Newton–Raphson method. A linear of sub-problems is generated by transferring the nonlinear problem with perturbation quantities and then approximated by summation of the solutions related to several sub-problems. In this study, a nonlinear load control procedure is generated and implemented for structures. Several numerical examples of known trusses are given to show the applicability of the proposed perturbation procedure without considering the passing limit points. The results reveal that perturbation modeling methodology for investigating the structural performance of various applications has high accuracy and low computational cost of convergence analysis, compared with the Newton–Raphson method.
2020-04-28T19:00:01Z
2020-04-28T19:00:01Z
2020-04-24
2020-04-28T14:14:18Z
Article - Refereed
Dehghani, H.; Mansouri, I.; Farzampour, A.; Hu, J.W. Improved Homotopy Perturbation Method for Geometrically Nonlinear Analysis of Space Trusses. Appl. Sci. 2020, 10, 2987.
http://hdl.handle.net/10919/97929
https://doi.org/10.3390/app10082987
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/642772023-06-23T15:23:00Zcom_10919_23747com_10919_5539col_10919_23748
Clay Mineral Image Collection for Education in Geotechnical Engineering and the Earth Sciences
Stone, Gordon
Dove, Joseph E.
Han, Nizhou
Dove, Patricia M.
Civil and Environmental Engineering
Clay mineral
Scanning electron microscopy
Engineering education
This file contains a collection of scanning electron microscope images of Kaolinite and Bentonite pure clay minerals, and the fine portion of a natural soil.
2015-12-03T22:19:23Z
2015-12-03T22:19:23Z
2015-12-03
Presentation
Image
http://hdl.handle.net/10919/64277
en
http://creativecommons.org/licenses/by-nc/3.0/us/
Creative Commons Attribution-NonCommercial 3.0 United States
oai:vtechworks.lib.vt.edu:10919/896522023-11-29T16:17:28Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539com_10919_5524col_10919_78882col_10919_23748col_10919_89575
A Novel Decentralized Game-Theoretic Adaptive Traffic Signal Controller: Large-Scale Testing
Abdelghaffar, Hossam M.
Rakha, Hesham A.
Civil and Environmental Engineering
Virginia Tech Transportation Institute
traffic signal control
game theory
decentralized control
large-scale network control
This paper presents a novel de-centralized flexible phasing scheme, cycle-free, adaptive traffic signal controller using a Nash bargaining game-theoretic framework. The Nash bargaining algorithm optimizes the traffic signal timings at each signalized intersection by modeling each phase as a player in a game, where players cooperate to reach a mutually agreeable outcome. The controller is implemented and tested in the INTEGRATION microscopic traffic assignment and simulation software, comparing its performance to that of a traditional decentralized adaptive cycle length and phase split traffic signal controller and a centralized fully-coordinated adaptive phase split, cycle length, and offset optimization controller. The comparisons are conducted in the town of Blacksburg, Virginia (38 traffic signalized intersections) and in downtown Los Angeles, California (457 signalized intersections). The results for the downtown Blacksburg evaluation show significant network-wide efficiency improvements. Specifically, there is a <inline-formula> <math display="inline"> <semantics> <mrow> <mn>23.6</mn> <mo>%</mo> </mrow> </semantics> </math> </inline-formula> reduction in travel time, a <inline-formula> <math display="inline"> <semantics> <mrow> <mn>37.6</mn> <mo>%</mo> </mrow> </semantics> </math> </inline-formula> reduction in queue lengths, and a <inline-formula> <math display="inline"> <semantics> <mrow> <mn>10.4</mn> <mo>%</mo> </mrow> </semantics> </math> </inline-formula> reduction in <inline-formula> <math display="inline"> <semantics> <msub> <mi>CO</mi> <mn>2</mn> </msub> </semantics> </math> </inline-formula> emissions relative to traditional adaptive traffic signal controllers. In addition, the testing on the downtown Los Angeles network produces a <inline-formula> <math display="inline"> <semantics> <mrow> <mn>35.1</mn> <mo>%</mo> </mrow> </semantics> </math> </inline-formula> reduction in travel time on the intersection approaches, a <inline-formula> <math display="inline"> <semantics> <mrow> <mn>54.7</mn> <mo>%</mo> </mrow> </semantics> </math> </inline-formula> reduction in queue lengths, and a <inline-formula> <math display="inline"> <semantics> <mrow> <mn>10</mn> <mo>%</mo> </mrow> </semantics> </math> </inline-formula> reduction in <inline-formula> <math display="inline"> <semantics> <msub> <mi>CO</mi> <mn>2</mn> </msub> </semantics> </math> </inline-formula> emissions compared to traditional adaptive traffic signal controllers. The results demonstrate significant potential benefits of using the proposed controller over other state-of-the-art centralized and de-centralized adaptive traffic signal controllers on large-scale networks both during uncongested and congested conditions.
2019-05-31T11:51:45Z
2019-05-31T11:51:45Z
2019-05-17
2019-05-31T06:01:54Z
Article - Refereed
Abdelghaffar, H.M.; Rakha, H.A. A Novel Decentralized Game-Theoretic Adaptive Traffic Signal Controller: Large-Scale Testing. Sensors 2019, 19, 2282.
http://hdl.handle.net/10919/89652
https://doi.org/10.3390/s19102282
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/1109752022-06-30T07:12:14Zcom_10919_23747com_10919_5539col_10919_23748
Demonstrating a Comprehensive Wastewater-Based Surveillance Approach That Differentiates Globally Sourced Resistomes
Prieto Riquelme, Maria Virginia
Garner, Emily
Gupta, Suraj
Metch, Jake
Zhu, Ni
Blair, Matthew F.
Arango-Argoty, Gustavo
Maile-Moskowitz, Ayella
Li, An-dong
Flach, Carl-Fredrik
Aga, Diana S.
Nambi, Indumathi M.
Larsson, D. G. Joakim
Bürgmann, Helmut
Zhang, Tong
Pruden, Amy
Vikesland, Peter J.
Antibiotic resistance
Microbiome
Wastewater-based surveillance
Sewage
Resistome
Metagenomics
Wastewater-based surveillance (WBS) for disease monitoring is highly promising but requires consistent methodologies that incorporate predetermined objectives, targets, and metrics. Herein, we describe a comprehensive metagenomics-based approach for global surveillance of antibiotic resistance in sewage that enables assessment of 1) which antibiotic resistance genes (ARGs) are shared across regions/communities; 2) which ARGs are discriminatory; and 3) factors associated with overall trends in ARGs, such as antibiotic concentrations. Across an internationally sourced transect of sewage samples collected using a centralized, standardized protocol, ARG relative abundances (16S rRNA gene-normalized) were highest in Hong Kong and India and lowest in Sweden and Switzerland, reflecting national policy, measured antibiotic concentrations, and metal resistance genes. Asian versus European/US resistomes were distinct, with macrolide-lincosamide-streptogramin, phenicol, quinolone, and tetracycline versus multidrug resistance ARGs being discriminatory, respectively. Regional trends in measured antibiotic concentrations differed from trends expected from public sales data. This could reflect unaccounted uses, captured only by the WBS approach. If properly benchmarked, antibiotic WBS might complement public sales and consumption statistics in the future. The WBS approach defined herein demonstrates multisite comparability and sensitivity to local/regional factors.
2022-06-29T12:51:59Z
2022-06-29T12:51:59Z
2022-06-27
Article - Refereed
http://hdl.handle.net/10919/110975
https://doi.org/10.1021/acs.est.1c08673
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
ACS
oai:vtechworks.lib.vt.edu:10919/751052023-11-29T00:22:43Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539com_10919_24215com_10919_23759com_10919_111113col_10919_70873col_10919_23748col_10919_24289col_10919_24352col_10919_111114
Disciplinary Influences on the Professional Identity of Civil Engineering Students: Starting the Conversation
Groen, Cassandra J.
Simmons, Denise Rutledge
McNair, Elizabeth D.
Civil and Environmental Engineering
Engineering Education
Institute for Creativity, Arts, and Technology (ICAT)
The Myers-Lawson School of Construction
As the discipline of civil engineering has evolved from an apprentice-based trade to a socially-engaged profession, the role of the civil engineer has responded to shifts within the ever-changing culture of society. These shifts and historical events have directly influenced what is considered to be valued civil engineering knowledge, behaviors, and practices that we teach to students during their undergraduate careers.
As part of a larger grounded theory study that is currently being conducted by the authors, the purpose of this paper is two-fold. First, we present the topic of professional identity formation as heavily influenced by unique historical events that shape the civil engineering discipline. . To establish the connection between identity formation and the history of civil engineering, we interpret historical events as constituents that create a disciplinary identity that is communicated to and subjectively applied by students during their undergraduate careers. Second, we hope to promote and invoke conversations surrounding the relevancy of civil engineering professional identity formation in engineering education among our colleagues within the technical disciplines.
Through this paper, we add to ongoing research exploring the professional formation of engineering identities and promote discussions surround this topic at the disciplinary level. While most research conducted on identity formation has been generalized to include all or most engineering disciplines, we focus our discussion solely on professional identity formation within the civil engineering discipline. To reinforce the relationship between the history of the civil engineering profession and students’ professional identity formation, we review the literature on these two areas of inquiry. In particular, we will frame our paper using the following key discussion points: 1) providing a brief overview of key historical events of civil engineering in the United States; 2) discussing the influence of this history on instructor pedagogies and student learning within civil engineering education; and 3) conceptualizing this learning process as a means of professional identity formation.
From this work, we will begin to understand how major historical shifts within our discipline maintain the potential to impact its future as we educate the next generation of civil engineering students. To conclude this paper, we will introduce current research that is being conducted by the authors to further understand the nuances of professional identity formation in undergraduate civil engineering students and how instructors may help or hinder that development.
2017-02-21T01:42:02Z
2017-02-21T01:42:02Z
2016-06
Conference proceeding
http://hdl.handle.net/10919/75105
en
American Society for Engineering Education Annual Conference
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
oai:vtechworks.lib.vt.edu:10919/1034522021-05-25T07:12:21Zcom_10919_78629com_10919_78628com_10919_23747com_10919_5539col_10919_78630col_10919_23748
Natural Organic Matter, Orthophosphate, pH, and Growth Phase Can Limit Copper Antimicrobial Efficacy for Legionella in Drinking Water
Song, Yang
Pruden, Amy
Edwards, Marc A.
Rhoads, William J.
Civil and Environmental Engineering
copper
Legionella pneumophila
corrosion control
natural organic matter
premise plumbing
Copper (Cu) is a promising antimicrobial for premise plumbing, where ions can be dosed directly via copper silver ionization or released naturally via corrosion of Cu pipes, but Cu sometimes inhibits and other times stimulates Legionella growth. Our overarching hypothesis was that water chemistry and growth phase control the net effect of Cu on Legionella. The combined effects of pH, phosphate concentration, and natural organic matter (NOM) were comprehensively examined over a range of conditions relevant to drinking water in bench-scale pure culture experiments, illuminating the effects of Cu speciation and precipitation. It was found that cupric ions (Cu2+) were drastically reduced at pH > 7.0 or in the presence of ligand-forming phosphates or NOM. Further, exponential phase L. pneumophila were 2.5x more susceptible to Cu toxicity relative to early stationary phase cultures. While Cu2+ ion was the most effective biocidal form of Cu, other inorganic ligands also had some biocidal impacts. A comparison of 33 large drinking water utilities' field-data from 1990 and 2018 showed that Cu2+ levels likely decreased more dramatically (>10x) than did the total or soluble Cu (2x) over recent decades. The overall findings aid in improving the efficacy of Cu as an actively dosed or passively released antimicrobial against L. pneumophila.
2021-05-24T14:24:11Z
2021-05-24T14:24:11Z
2021-02-02
Article - Refereed
0013-936X
http://hdl.handle.net/10919/103452
https://doi.org/10.1021/acs.est.0c06804
55
3
33428375
1520-5851
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
oai:vtechworks.lib.vt.edu:10919/1116332023-02-22T19:11:26Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78882col_10919_23748
Assessing and Validating the Ability of Machine Learning to Handle Unrefined Particle Air Pollution Mobile Monitoring Data Randomly, Spatially, and Spatiotemporally
Alazmi, Asmaa
Rakha, Hesham A.
Many epidemiological studies have evaluated the accuracy of machine learning models in predicting levels of particulate number (PN) and black carbon (BC) pollutant concentrations. However, few studies have investigated the ability of machine learning to predict the pollutant concentration with using unrefined mobile measurement data and explore the reliability of the prediction models. Additionally, researchers are moving away from using fixed-site data in favor of using mobile monitoring data in a variety of locations to develop hourly empirical models of particulate air pollution. This study compared the differences between long-term (daily average) and short-term (hourly average and 1 s unrefined data) model performance in three different classes of cross validation: randomly, spatially, and spatially temporally. This study used secondary data describing BC and PN pollutant levels in the rural location of Blacksburg (VA). Our results show that the model based on unrefined data was able to detect the pollutant hot spot areas with similar accuracy compared to the aggregated model. Moreover, the performance was found to improve when temporal data added to the model: the 10-fold MAE for the BC and PN were 0.44 μg/m<sup>3</sup> and 3391 pt/cm<sup>3</sup>, respectively, for the unrefined data (one second data) model. The findings detailed here will add to the literature on the correlation between data (pre)processing and the efficacy of machine learning models in predicting pollution levels while also enhancing our understanding of more reliable validation strategies.
2022-08-25T12:22:05Z
2022-08-25T12:22:05Z
2022-08-16
2022-08-25T11:18:07Z
Article - Refereed
Alazmi, A.; Rakha, H. Assessing and Validating the Ability of Machine Learning to Handle Unrefined Particle Air Pollution Mobile Monitoring Data Randomly, Spatially, and Spatiotemporally. Int. J. Environ. Res. Public Health 2022, 19, 10098.
http://hdl.handle.net/10919/111633
https://doi.org/10.3390/ijerph191610098
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/1111942022-07-12T07:31:45Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_18629col_10919_23748
Review of regulation techniques of asphalt pavement high temperature for climate change adaptation
Gong, Zhenlong
Zhang, Letao
Wu, Jiaxi
Xiu, Zhao
Wang, Linbing
Miao, Yinghao
Asphalt pavement is vulnerable to the temperature rising and extremely high-temperature weather caused by climate change. The regulation techniques of asphalt pavement high temperature have become a growing concern to adapt to climate change. This paper reviewed the state of the art on regulating asphalt pavement high temperature. Firstly, the influencing factors and potential regulation paths of asphalt pavement temperature were summarized. The regulation techniques were categorized into two categories. One is to regulate the heat transfer process, including enhancing reflection, increasing thermal resistance, and evaporation cooling. The other is to regulate through heat collection and transfer or conversion, including embedded heat exchange system, phase change asphalt pavement, and thermoelectric system. Then, the regulation techniques in the literature were reviewed one by one in terms of cooling effects and pavement performance. The issues that still need to be improved were also discussed. Finally, the regulation techniques were compared from the perspectives of theoretical cooling effects, construction convenience, and required maintenance. It can provide reference for understanding the development status of asphalt pavement high temperature regulation techniques and technique selection in practice.
2022-07-11T14:28:24Z
2022-07-11T14:28:24Z
2022-07-03
2022-07-10T03:19:29Z
Article - Refereed
Journal of Infrastructure Preservation and Resilience. 2022 Jul 03;3(1):9
http://hdl.handle.net/10919/111194
https://doi.org/10.1186/s43065-022-00054-5
en
http://creativecommons.org/licenses/by/4.0/
The Author(s)
Creative Commons Attribution 4.0 International
oai:vtechworks.lib.vt.edu:10919/1095662022-04-08T04:37:40Zcom_10919_23747com_10919_5539col_10919_23748
Growing farms and groundwater depletion in the Kansas High Plains
Ao, Yufei Z.
Hendricks, Nathan P.
Marston, Landon T.
farm size
farm structure
rebound effect
groundwater
aquifer
irrigation efficiency
High Plains
The average farm size has more than doubled within the United States over the last three decades, transforming the agricultural industry and rural farming communities. It is unclear, however, how this ubiquitous trend has affected and is affected by the environment, particularly groundwater resources critical for food production. Here, we leverage a unique multi-decadal dataset of well-level groundwater withdrawals for crop irrigation over the Kansas High Plains Aquifer to determine the interactions between groundwater depletion and growing farms. Holding key technological, management, and environmental variables fixed, we show that doubling a farm's irrigated cropland decreases groundwater extractions by 2%-5% depending on the initial farm size. However, a corresponding shift by larger farms to different irrigation technologies offsets this reduction in groundwater use, leading to a slight increase in overall groundwater use. We find groundwater depletion increases the likelihood farmland is sold to a larger farm, amplifying the cycle of groundwater depletion and the consolidation of farmland.
2022-04-06T12:17:42Z
2022-04-06T12:17:42Z
2021-08
Article - Refereed
1748-9326
84065
https://doi.org/10.1088/1748-9326/ac1816
16
8
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Kansas
United States
oai:vtechworks.lib.vt.edu:10919/1120692023-11-29T16:17:29Zcom_10919_23747com_10919_5539com_10919_5524col_10919_23748col_10919_89575
Policy and industry implications of the potential market penetration of electric vehicles with eco-cooperative adaptive cruise control
Bas, Javier
Zofio, Jose L.
Cirillo, Cinzia
Chen, Hao
Rakha, Hesham A.
Eco-CACC
Electric vehicle
Fuel savings
Market share
The Eco-Cooperative Adaptive Cruise Control (Eco-CACC) makes use of an algorithm to compute energy-optimized speed profiles within the vicinity of signalized intersections. We conduct a stated choice experiment to unveil the inclination of drivers towards the Eco-CACC and to calculate its potential market share. To do so, we consider the performance of the system in field and simulated tests, as well as different types of drivers. Models of discrete choice are used to identify key elements in the adoption of this technology and its market penetration. The study has been performed for gasoline and electric vehicles, as well as for different categories of roads (arterial, highways and both), separately, exploring the effect of the advantages that the Eco-CACC features bring to both. Our results demonstrate, for the gasoline-powered, that potential purchasers perceive a clear trade-off between the cost of the system and the fuel savings that it provides. This is not the case for potential electric vehicles purchasers, for whom the cost-benefit analysis is adverse, mainly due to the low cost of electricity compared to gasoline. Nevertheless, the market shares resulting from the estimated models give a significant quota to the alternatives that include the Eco-CACC, resulting from favorable attitudes towards environmentally friendly technological innovations.
2022-10-04T16:46:23Z
2022-10-04T16:46:23Z
2022-10
Article - Refereed
0965-8564
http://hdl.handle.net/10919/112069
https://doi.org/10.1016/j.tra.2022.08.007
164
1879-2375
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Pergamon-Elsevier
oai:vtechworks.lib.vt.edu:10919/963822021-10-08T16:43:29Zcom_10919_78629com_10919_78628com_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78630col_10919_78882col_10919_23748
Occurrence of Free Amino Acids in the Source Waters of Zhejiang Province, China, and Their Removal and Transformation in Drinking Water Systems
Yang, Yulong
Yu, Qi
Zhou, Ruonan
Feng, Jiao
Zhang, Kejia
Li, Xueyan
Ma, Xiaoyan
Dietrich, Andrea M.
Civil and Environmental Engineering
solid phase extraction
disinfection byproduct precursor
free amino acids
C-DBP
N-DPB
Free amino acids (FAAs) are key components of the global nitrogen cycle and important disinfection byproduct (DBP) precursors. The knowledge gap of FAA occurrence in source and engineered water is discussed in this paper. Solid phase extraction and post column derivatization was combined with gas chromatography–mass spectrometry to simultaneously detect μg/L concentrations of FAAs. This method efficiently detects alanine (Ala), threonine (Thr), serine (Ser), valine (Val), leucine (Leu), isoleucine (Ile), proline (Pro), aspartic (Asp), phenylalanine (Phe), and glutamic acid (Glu) with good linearity, accuracy, and precision. An investigation of FAAs in surface waters in Zhejiang Province found concentrations of 1.48–14.73 μg/L Ala, 0.20–2.39 μg/L Thr, 0.41–7.84 μg/L Val, 0.21–6.86 μg/L Ser, 0.11–4.16 μ;g/L Leu, 0.57–1.54 μg/L Ile, 0.24–8.06 μg/L Pro, 0.42–4.73 μg/L Asp, 0.30–3.01 μg/L Phe, and 0.12–3.83 μg/L Glu. Phe and tyrosine (Tyr) exhibited higher trichloromethane (TCM) formation (1029–1148 μg/mmolAA) than dichloroacetonitrile (DCAN) formation (333–347 μg/mmolAA). Asp and Glu demonstrated the opposite trend: higher DCAN (570–1106 μg/mmolAA) formation than TCM (137–506 μg/mmolAA).
2020-01-10T14:38:08Z
2020-01-10T14:38:08Z
2019-12-24
2020-01-10T09:02:09Z
Article - Refereed
Yang, Y.; Yu, Q.; Zhou, R.; Feng, J.; Zhang, K.; Li, X.; Ma, X.; Dietrich, A.M. Occurrence of Free Amino Acids in the Source Waters of Zhejiang Province, China, and Their Removal and Transformation in Drinking Water Systems. Water 2019, 12, 73.
http://hdl.handle.net/10919/96382
https://doi.org/10.3390/w12010073
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/1040382023-06-23T15:22:50Zcom_10919_23747com_10919_5539col_10919_23748
The impact of hazard-consistent ground motion scenarios selection on structural seismic risk estimation
Zaker Esteghamati, Mohsen
Bahrampouri, Mahdi
Rodriguez-Marek, Adrian
Monte Carlo seismic hazard analysis
Hazard deaggregation
Performance-based earthquake engineering
Seismic scenario selection
Structural risk-based evaluation requires a large number of time-history analyses at different ground motion (GM) intensity levels, where the scenarios (e.g. magnitude and distance) of the GMs used in the time-history analyses should be consistent with the site's hazard. The current practice of GM selection typically simplifies the choice of scenario to either an average scenario or the modal scenarios based on the site's hazard deaggregation results. This paper investigates the impact of hazard deaggregation and scenario selection on estimating structural seismic risk. For a hypothetical site in the Eastern US, a Monte Carlo seismic hazard analysis is performed to derive a site-consistent GM suite that captures 1,000,000 years of the site's seismic activity. The complete GM suite consisting of 99,917 records is then used to perform nonlinear dynamic analyses on a mid-rise concrete office building to derive a benchmark seismic demand curve. Subsequently, four GM sets are selected based on average and modal scenarios from two different hazard deaggregation formulation, and the resulting demand curves are compared to the benchmark. The results show that the hazard deaggregation method and scenario choice impacts the demand curve estimation. When deaggregation is performed on IM exceedance, GMs that were selected based on both methods agree well with the benchmark up to higher damage states where mode-based records outperform average-based records. On the other hand, when deaggregation is formulated based on IM occurrence, average scenario-based GMs better match the benchmark, except for higher damage states where again modal scenario-based GMs are in better agreement with the benchmark.
2021-06-27T03:46:51Z
2021-06-27T03:46:51Z
2021
Conference proceeding
http://hdl.handle.net/10919/104038
en
Geotechnical Engineering for Extreme Events (Geo-Extreme2021)
http://creativecommons.org/licenses/by-nc/4.0/
Attribution-NonCommercial 4.0 International
The Geo-Institute of ASCE
oai:vtechworks.lib.vt.edu:10919/978592022-02-25T02:39:53Zcom_10919_23747com_10919_5539col_10919_23748
Listeria monocytogenes in Retail Delicatessens: An Interagency Risk Assessment-Risk Mitigations
Gallagher, Daniel L.
Pouillot, Regis
Hoelzer, Karin
Tang, Jia
Dennis, Sherri B.
Kause, Janell R.
Civil and Environmental Engineering
Listeria monocytogenes
Retail
Risk assessment
Scenario analysis
Virtual retail deli
Cross-contamination, improper holding temperatures, and insufficient sanitary practices are known retail practices that may lead to product contamination and growth of Listeria monocytogenes. However, the relative importance of control options to mitigate the risk of invasive listeriosis from ready-to-eat (RTE) products sliced or prepared at retail is not well understood. This study illustrates the utility of a quantitative risk assessment model described in a first article of this series (Pouillot, R., D. Gallagher, J. Tang, K. Hoelzer, J. Kause, and S. B. Dennis, J. Food Prot. 78: 134-145, 2015) to evaluate the public health impact associated with changes in retail deli practices and interventions. Twenty-two mitigation scenarios were modeled and evaluated under six different baseline conditions. These scenarios were related to sanitation, worker behavior, use of growth inhibitors, cross-contamination, storage temperature control, and reduction of the level of L. monocytogenes on incoming RTE food products. The mean risk per serving of RTE products obtained under these scenarios was then compared with the risk estimated in the baseline condition. Some risk mitigations had a consistent impact on the predicted listeriosis risk in all baseline conditions (e.g. presence or absence of growth inhibitor), whereas others were greatly dependent on the initial baseline conditions or practices in the deli (e.g. preslicing of products). Overall, the control of the bacterial growth and the control of contamination at its source were major factors of listeriosis risk in these settings. Although control of cross-contamination and continued sanitation were also important, the decrease in the predicted risk was not amenable to a simple solution. Findings from these predictive scenario analyses are intended to encourage improvements to retail food safety practices and mitigation strategies to control L. monocytogenes in RTE foods more effectively and to demonstrate the utility of quantitative risk assessment models to inform risk management decisions.
2020-04-21T18:12:39Z
2020-04-21T18:12:39Z
2016-07
Article - Refereed
0362-028X
http://hdl.handle.net/10919/97859
https://doi.org/10.4315/0362-028X.JFP-15-336
79
7
27357026
1944-9097
en
http://creativecommons.org/publicdomain/zero/1.0/
Creative Commons CC0 1.0 Universal Public Domain Dedication
oai:vtechworks.lib.vt.edu:10919/1144712023-04-12T07:12:58Zcom_10919_23747com_10919_5539col_10919_23748
The field of human building interaction for convergent research and innovation for intelligent built environments
Becerik-Gerber, Burcin
Lucas, Gale
Aryal, Ashrant
Awada, Mohamad
Berges, Mario
Billington, Sarah
Boric-Lubecke, Olga
Ghahramani, Ali
Heydarian, Arsalan
Hoelscher, Christoph
Jazizadeh, Farrokh
Khan, Azam
Langevin, Jared
Liu, Ruying
Marks, Frederick
Mauriello, Matthew Louis
Murnane, Elizabeth
Noh, Haeyoung
Pritoni, Marco
Roll, Shawn
Schaumann, Davide
Seyedrezaei, Mirmahdi
Taylor, John E.
Zhao, Jie
Zhu, Runhe
Personalized thermal comfort
energy-efficiency
social practice
design
impact
framework
behavior
systems
information
strategies
Human-Building Interaction (HBI) is a convergent field that represents the growing complexities of the dynamic interplay between human experience and intelligence within built environments. This paper provides core definitions, research dimensions, and an overall vision for the future of HBI as developed through consensus among 25 interdisciplinary experts in a series of facilitated workshops. Three primary areas contribute to and require attention in HBI research: humans (human experiences, performance, and well-being), buildings (building design and operations), and technologies (sensing, inference, and awareness). Three critical interdisciplinary research domains intersect these areas: control systems and decision making, trust and collaboration, and modeling and simulation. Finally, at the core, it is vital for HBI research to center on and support equity, privacy, and sustainability. Compelling research questions are posed for each primary area, research domain, and core principle. State-of-the-art methods used in HBI studies are discussed, and examples of original research are offered to illustrate opportunities for the advancement of HBI research.
2023-04-11T16:56:09Z
2023-04-11T16:56:09Z
2022-12-21
Article - Refereed
22092
http://hdl.handle.net/10919/114471
https://doi.org/10.1038/s41598-022-25047-y
12
1
36543830
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Nature Portfolio
oai:vtechworks.lib.vt.edu:10919/1087612022-04-08T04:37:40Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539col_10919_70873col_10919_23748
Environmental Impact Bonds: a common framework and looking ahead
Brand, M. W.
Quesnel, K.
Saksa, P.
Ulibarri, N.
Bomblies, A.
Mandle, L.
Allaire, M.
Wing, O.
Tobin-de la Puente, J.
Parker, E. A.
Nay, J.
Sanders, Brett F.
Rosowsky, D.
Lee, J.
Johnson, K.
Gudino-Elizondo, N.
Ajami, N.
Wobbrock, N.
Adriaens, P.
Grant, Stanley B.
Wright, S.
Gartner, T.
Knight, Z.
Gibbons, J. P.
A frequent barrier to addressing some of our world’s most pressing environmental challenges is a lack of funding. Currently, environmental project funding largely comes from philanthropic and public sources, but this does not meet current needs. Increased coordination and collaboration between multiple levels and sectors of government, in addition to private sector funding, can help address the environmental funding challenge. New financial tools and strategies can enable this transition and facilitate uptake of innovative solutions. One such mechanism, the Environmental Impact Bond (EIB), is an emerging financial tool with the potential to transformthe environmental funding landscape. However, these financial instruments are not well understood or recognized beyond those actively involved in EIB projects or in the field of conservation finance. As EIBs gain momentum, there is a clear need for a common framework, including definitions and nomenclature, research needs, and outlook for the future. In this paper, we define EIB mechanics, elucidate the difference between EIBs and Green Bonds, and propose a common vocabulary for the field. Drawing on first-hand experience with the few EIBs which have been deployed, we review and assess lessons learned, trends, and paths for the future. Finally, we propose a set of future targets and discuss research goals for the field to unify around. Through this work, we identify a concrete set of research gaps and objectives, providing evidence for EIBs as one important tool in the environmental finance toolbox.
2022-02-19T16:40:23Z
2022-02-19T16:40:23Z
2021-07-27
2022-02-19T16:40:12Z
Article - Refereed
http://hdl.handle.net/10919/108761
https://doi.org/10.1088/2634-4505/ac0b2c
1
2
Grant, Stanley [0000-0001-6221-7211]
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
oai:vtechworks.lib.vt.edu:10919/1140702023-03-11T08:33:21Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78882col_10919_23748
A Meso-Scale Petri Net Model to Simulate a Massive Evacuation along the Highway System
Qabaja, Hamzeh
Ashqer, Mujahid I.
Bikdash, Marwan
Ashqar, Huthaifa I.
Natural disasters may require that the residents of the affected area be evacuated immediately using a potentially damaged infrastructure. In this paper, we developed a mesoscopic simulation modeling approach for modeling traffic flow over a large geographic area and involving many people and vehicles. This study proposed a novel model, namely, Colored Deterministic and Stochastic Petri Net (CDSPN), which can mesoscopically provide an individual vehicular traffic dynamic. Each vehicle has a unique identifier, speed, distance to go, assigned target, and a specific route. It also proposed a method to automatically construct a Petri net model that represents the evacuation of Guilford County (GC), North Carolina, from standard Geographic Information Systems (GIS) shapefiles. We showed that this model could successfully simulate the dynamics of hundreds of thousands of vehicles moving on the highway system towards pre-specified safe targets such as medical facilities, exit points, or designated shelters. The vehicles are assumed to obey traffic laws, and the model reflects the complexities of the actual highway systems. The developed software can be used to analyze in reasonable detail the evacuation process, such as identifying bottlenecks and estimating efficiency and the time needed. An explicit list of 18 assumptions is stated and discussed. The Petri net for GC evacuation is reasonably massive, consisting of 35,476 places and 43,540 transitions with 531,595 colored tokens, where each token represents a vehicle in GC. We simulate the evacuation, develop statistics, and evaluate patterns of evaluation. We found that the evacuation took about 8.7 h.
2023-03-10T14:08:15Z
2023-03-10T14:08:15Z
2023-03-02
2023-03-10T14:01:42Z
Article - Refereed
Qabaja, H.; Ashqer, M.I.; Bikdash, M.; Ashqar, H.I. A Meso-Scale Petri Net Model to Simulate a Massive Evacuation along the Highway System. Future Transp. 2023, 3, 311-328.
http://hdl.handle.net/10919/114070
https://doi.org/10.3390/futuretransp3010019
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/848462023-06-23T15:22:55Zcom_10919_78629com_10919_78628com_10919_23747com_10919_5539col_10919_78630col_10919_23748
Survival of the Enveloped Virus Phi6 in Droplets as a Function of Relative Humidity, Absolute Humidity, and Temperature
Prussin, Aaron J. II
Schwake, David Otto
Lin, Kaisen
Gallagher, Daniel L.
Buttling, Lauren G.
Marr, Linsey C.
Civil and Environmental Engineering
Influenza
Coronavirus
SARS
MERS
Humidity
Infectious diseases caused by enveloped viruses, such as influenza, severe acute respiratory syndrome (SARS), and Middle East respiratory syndrome (MERS), cause thousands of deaths and billions of dollars of economic losses per year. Studies have found a relationship among temperature, humidity, and influenza virus incidence, transmission, or survival; however, there are contradictory claims about whether absolute humidity (AH) or relative humidity (RH) is most important in mediating virus infectivity. Using the enveloped bacteriophage Phi6, which has been suggested as a surrogate for influenza viruses and coronaviruses, we designed a study to discern whether AH, RH, or temperature is a better predictor of virus survival in droplets. Our results show that Phi6 survived best at high (>85%) and low (<60%) RHs, with a significant decrease in infectivity at mid-range RHs (~60 to 85%). At an AH of less than 22 g · m⁻³, the loss in infectivity was less than 2 orders of magnitude; however, when the AH was greater than 22 g · m⁻³, the loss in infectivity was typically greater than 6 orders of magnitude. At a fixed RH of 75%, infectivity was very sensitive to temperature, decreasing two orders of magnitude between 19°C and 25°C. We used random forest modeling to identify the best environmental predictors for modulating virus infectivity. The model explained 83% of variation in Phi6 infectivity and suggested that RH is the most important factor in controlling virus infectivity in droplets. This research provides novel information about the complex interplay between temperature, humidity, and the survival of viruses in droplets.
2018-08-16T18:26:01Z
2018-08-16T18:26:01Z
2018-04-06
Article - Refereed
http://hdl.handle.net/10919/84846
https://doi.org/10.1128/AEM.00551-18
84
12
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
American Society for Microbiology
oai:vtechworks.lib.vt.edu:10919/987922021-07-15T19:26:44Zcom_10919_78629com_10919_78628com_10919_23747com_10919_5539col_10919_78630col_10919_23748
Can indoor sports centers be allowed to re-open during the COVID-19 pandemic based on a certificate of equivalence?
Blocken, B.
van Druenen, T.
van Hooff, T.
Verstappen, P. A.
Marchal, T.
Marr, Linsey C.
Civil and Environmental Engineering
Corona virus
Sports club
Gym
Fitness
Aerodynamics
Building ventilation
Filters
Face masks
COVID-19
Within a time span of only a few months, the SARS-CoV-2 virus has managed to spread across the world. This virus can spread by close contact, which includes large droplet spray and inhalation of microscopic droplets, and by indirect contact via contaminated objects. While in most countries, supermarkets have remained open, due to the COVID-19 pandemic, authorities have ordered many other shops, restaurants, bars, music theaters and indoor sports centers to be closed. As part of COVID-19 (semi)lock-down exit strategies, many government authorities are now (May-June 2020) allowing a gradual re-opening, where sometimes indoor sport centers are last in line to be permitted to re-open. This technical note discusses the challenges in safely re-opening these facilities and the measures already suggested by others to partly tackle these challenges. It also elaborates three potential additional measures and based on these additional measures, it suggests the concept of a certificate of equivalence that could allow indoor sports centers with such a certificate to re-open safely and more rapidly. It also attempts to stimulate increased preparedness of indoor sports centers that should allow them to remain open safely during potential next waves of SARS-CoV-2 as well as future pandemics. It is concluded that fighting situations such as the COVID-19 pandemic and limiting economic damage requires increased collaboration and research by virologists, epidemiologists, microbiologists, aerosol scientists, building physicists, building services engineers and sports scientists.
2020-06-09T12:00:20Z
2020-06-09T12:00:20Z
2020-05-31
Article - Refereed
http://hdl.handle.net/10919/98792
https://doi.org/10.1016/j.buildenv.2020.107022
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Elsevier
oai:vtechworks.lib.vt.edu:10919/867762023-11-29T12:17:29Zcom_10919_5com_10919_25799com_10919_24227com_10919_5532com_10919_23747com_10919_5539com_10919_23967com_10919_5557col_10919_70873col_10919_24302col_10919_23748col_10919_24279
Effects of Large Wood on Floodplain Connectivity in a Headwater Mid-Atlantic Stream
Keys, Tyler A.
Governer, Heather
Jones, C. Nathan
Hession, W. Cully
Hester, Erich T.
Scott, Durelle T.
Civil and Environmental Engineering
Biological Systems Engineering
Forest Resources and Environmental Conservation
04 Earth Sciences
05 Environmental Sciences
09 Engineering
Environmental Engineering
Large wood (LW) plays an essential role in aquatic ecosystem health and function. Traditionally, LW has been removed from streams to minimize localized flooding and increase conveyance efficiency. More recently, LW is often added to streams as a component of stream and river restoration activities. While much research has focused on the role of LW in habitat provisioning, geomorphic stability, and hydraulics at low to medium flows, we know little about the role of LW during storm events. To address this question, we investigated the role of LW on floodplain connectivity along a headwater stream in the Mid-Atlantic region of the United States. Specifically, we conducted two artificial floods, one with and one without LW, and then utilized field measurements in conjunction with hydrodynamic modeling to quantify floodplain connectivity during the experimental floods and to characterize potential management variables for optimized restoration activities. Experimental observations show that the addition of LW increased maximum floodplain inundation extent by 34%, increased floodplain inundation depth by 33%, and decreased maximum thalweg velocity by 10%. Model results demonstrated that different placement of LW along the reach has the potential to increase floodplain flow by up to 40%, with highest flooding potential at cross sections with high longitudinal velocity and shallow depth. Additionally, model simulations show that the effects of LW on floodplain discharge decrease as storm recurrence interval increases, with no measurable impact at a recurrence interval of more than 25 years.
2019-01-18T19:48:32Z
2019-01-18T19:48:32Z
2018-05-08
2019-01-18T19:48:31Z
Article - Refereed
http://hdl.handle.net/10919/86776
118
Scott, Durelle [0000-0002-5792-789X]
Hession, William [0000-0002-6323-3827]
Hester, Erich [0000-0002-7510-5136]
en
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
oai:vtechworks.lib.vt.edu:10919/1032872023-11-29T19:07:26Zcom_10919_78629com_10919_78628com_10919_8195com_10919_25799com_10919_5540com_10919_23747com_10919_5539col_10919_78630col_10919_78882col_10919_71752col_10919_23748
Air Quality in Southeast Brazil during COVID-19 Lockdown: A Combined Satellite and Ground-Based Data Analysis
Brandao, Rayssa
Foroutan, Hosein
Civil and Environmental Engineering
air quality
OMI
NO2
PM2.5
São Paulo
Rio de Janeiro
With the current COVID-19 pandemic being spread all over the world, lockdown measures are being implemented, making air pollution levels go down in several countries. In this context, the air quality changes in the highly populated and trafficked Brazilian states of São Paulo (SP) and Rio de Janeiro (RJ) were addressed using a combination of satellite and ground-based daily data analysis. We explored nitrogen dioxide (NO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula>) and fine particulate matter (PM<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mrow><mn>2.5</mn></mrow></msub></semantics></math></inline-formula>) daily levels for the month of May from 2015–2020. Daily measurements of NO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> column concentrations from the Ozone Monitoring Instrument (OMI) aboard NASA’s Aura satellite were analyzed and decreases of 42% and 49.6% were found for SP and RJ, respectively, during the year 2020 compared to the 2015–2019 average. Besides NO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> column retrievals, ground-based data measured by the Brazilian States Environmental Institutions were analyzed and correlated with satellite retrievals. Correlation coefficients between year-to-year changes in satellite column and ground-based concentrations were 77% and 53% in SP and RJ, respectively. Ground-based data showed 13.3% and 18.8% decrease in NO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> levels for SP and RJ, respectively, in 2020 compared to 2019. In SP, no significant change in PM<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mrow><mn>2.5</mn></mrow></msub></semantics></math></inline-formula> was observed in 2020 compared to 2019. To further isolate the effect of emissions reduction due to the lockdown, meteorological data and number of wildfire hotspots were analyzed. NO<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mn>2</mn></msub></semantics></math></inline-formula> concentrations showed negative and positive correlations with wind speed and temperature, respectively. PM<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mrow></mrow><mrow><mn>2.5</mn></mrow></msub></semantics></math></inline-formula> concentration distributions suggested an influence by the wildfires in the southeast region of the country. Synergistic analyses of satellite retrievals, surface level concentrations, and weather data provide a more complete picture of changes to pollutant levels.
2021-05-14T13:14:19Z
2021-05-14T13:14:19Z
2021-05-01
2021-05-13T14:34:44Z
Article - Refereed
Brandao, R.; Foroutan, H. Air Quality in Southeast Brazil during COVID-19 Lockdown: A Combined Satellite and Ground-Based Data Analysis. Atmosphere 2021, 12, 583.
http://hdl.handle.net/10919/103287
https://doi.org/10.3390/atmos12050583
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
São Paulo; Rio de Janeiro
MDPI
oai:vtechworks.lib.vt.edu:10919/750302024-03-12T15:59:27Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539col_10919_70873col_10919_23748
Effects of current generation and electrolyte pH on reverse salt flux across thin film composite membrane in osmotic microbial fuel cells
Qin, Mohan
Abu-Reesh, Ibrahim M.
He, Zhen
Civil and Environmental Engineering
Technology
Engineering, Environmental
Environmental Sciences
Water Resources
Engineering
Environmental Sciences & Ecology
Osmotic microbial fuel cells
Reverse salt flux
Electricity generation
Catholyte pH
Ion transport
WASTE-WATER TREATMENT
BIOELECTROCHEMICAL SYSTEMS
ELECTRICITY-GENERATION
OSMOSIS MEMBRANE
BIOELECTRICITY GENERATION
DRAW SOLUTIONS
DESALINATION
PERFORMANCE
RECOVERY
BIOREACTOR
2017-02-14T21:46:31Z
2017-02-14T21:46:31Z
2016-11-15
Article - Refereed
0043-1354
http://hdl.handle.net/10919/75030
https://doi.org/10.1016/j.watres.2016.09.028
105
en
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000385902000060&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=930d57c9ac61a043676db62af60056c1
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
Pergamon-Elsevier
oai:vtechworks.lib.vt.edu:10919/1181552024-03-15T13:19:06Zcom_10919_5com_10919_25799com_10919_98410com_10919_25796com_10919_23747com_10919_5539col_10919_70873col_10919_98411col_10919_23748
Freshwater salinization syndrome limits management efforts to improve water quality
Maas, Carly M.
Kaushal, Sujay S.
Rippy, Megan A.
Mayer, Paul M.
Grant, Stanley B.
Shatkay, Ruth R.
Malin, Joseph T.
Bhide, Shantanu V.
Vikesland, Peter
Krauss, Lauren
Reimer, Jenna E.
Yaculak, Alexis M.
freshwater salinization
chemical cocktails
urban streams pollution
riparian buffer
temporal monitoring
longitudinal monitoring
restoration
Freshwater Salinization Syndrome (FSS) refers to groups of biological, physical, and chemical impacts which commonly occur together in response to salinization. FSS can be assessed by the mobilization of chemical mixtures, termed “chemical cocktails”, in watersheds. Currently, we do not know if salinization and mobilization of chemical cocktails along streams can be mitigated or reversed using restoration and conservation strategies. We investigated 1) the formation of chemical cocktails temporally and spatially along streams experiencing different levels of restoration and riparian forest conservation and 2) the potential for attenuation of chemical cocktails and salt ions along flowpaths through conservation and restoration areas. We monitored high-frequency temporal and longitudinal changes in streamwater chemistry in response to different pollution events (i.e., road salt, stormwater runoff, wastewater effluent, and baseflow conditions) and several types of watershed management or conservation efforts in six urban watersheds in the Chesapeake Bay watershed. Principal component analysis (PCA) indicates that chemical cocktails which formed along flowpaths (i.e., permanent reaches of a stream) varied due to pollution events. In response to winter road salt applications, the chemical cocktails were enriched in salts and metals (e.g., Na+, Mn, and Cu). During most baseflow and stormflow conditions, chemical cocktails were less enriched in salt ions and trace metals. Downstream attenuation of salt ions occurred during baseflow and stormflow conditions along flowpaths through regional parks, stream-floodplain restorations, and a national park. Conversely, chemical mixtures of salt ions and metals, which formed in response to multiple road salt applications or prolonged road salt exposure, did not show patterns of rapid attenuation downstream. Multiple linear regression was used to investigate variables that influence changes in chemical cocktails along flowpaths. Attenuation and dilution of salt ions and chemical cocktails along stream flowpaths was significantly related to riparian forest buffer width, types of salt pollution, and distance downstream. Although salt ions and chemical cocktails can be attenuated and diluted in response to conservation and restoration efforts at lower concentration ranges, there can be limitations in attenuation during road salt events, particularly if storm drains bypass riparian buffers.
2024-02-26T14:49:16Z
2024-02-26T14:49:16Z
2023-09-22
Article - Refereed
2296-665X
https://hdl.handle.net/10919/118155
https://doi.org/10.3389/fenvs.2023.1106581
11
Rippy, Megan [0000-0002-0575-8342]
Grant, Stanley [0000-0001-6221-7211]
Vikesland, Peter [0000-0003-2654-5132]
37841559
2296-665X
en
https://www.ncbi.nlm.nih.gov/pubmed/37841559
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Frontiers
oai:vtechworks.lib.vt.edu:10919/793422021-10-08T16:43:30Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78882col_10919_23748
Using a Molecular Dynamics Simulation to Investigate Asphalt Nano-Cracking under External Loading Conditions
Hou, Yue
Wang, Linbing
Wang, Dawei
Qu, Xin
Wu, Jiangfeng
Civil and Environmental Engineering
MD simulation
asphalt
nano-cracking
low temperature
Recent research shows that macro-scale cracking in asphalt binder may originate from its intrinsic defects at the nano-scale. In this paper, a molecular dynamics (MD) simulation was conducted to evaluate the nucleation of natural defects in asphalt. The asphalt microstructure was modeled using an ensemble of three different types of molecules to represent a constituent species: asphaltenes, naphthene aromatics and saturates, where the weight proportion of 20:60:20 was used to create an asphalt-like ensemble of molecules. Tension force was then applied on the molecular boundaries to study the crack initiation and propagation. It was discovered that the natural distribution of atoms at microscale would affect the intrinsic defects in asphalt and further influence crack initiation and propagation in asphalt.
2017-09-20T18:34:05Z
2017-09-20T18:34:05Z
2017-07-28
2017-09-20T18:34:05Z
Article - Refereed
Hou, Y.; Wang, L.; Wang, D.; Qu, X.; Wu, J. Using a Molecular Dynamics Simulation to Investigate Asphalt Nano-Cracking under External Loading Conditions. Appl. Sci. 2017, 7, 770.
http://hdl.handle.net/10919/79342
https://doi.org/10.3390/app7080770
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/932582020-10-08T18:34:33Zcom_10919_23747com_10919_5539col_10919_23748
Light-driven nitrous oxide production via autotrophic denitrification by self-photosensitized Thiobacillus denitrificans
Chen, Man
Zhou, Xiao-Fang
Yu, Yu-Qing
Liu, Xing
Zeng, Raymond Jian-Xiong
Zhou, Shun-Gui
He, Zhen
Civil and Environmental Engineering
Biohybrid system
Autotrophic denitrification
Semiconductors
Cadmium sulfide
Nitrous oxide
N2O (Nitrous oxide, a booster oxidant in rockets) has attracted increasing interest as a means of enhancing energy production, and it can be produced by nitrate (NO3-) reduction in NO3--loading wastewater. However, conventional denitrification processes are often limited by the lack of bioavailable electron donors. In this study, we innovatively propose a self-photosensitized nonphototrophic Thiobacillus denitrificans (T. denitrificans-CdS) that is capable of NO(3)(-)reduction and N2O production driven by light. The system converted > 72.1 +/- 1.1% of the NO3--N input to N2O-N, and the ratio of N2O-N in gaseous products was > 96.4 +/- 0.4%. The relative transcript abundance of the genes encoding the denitrifying proteins in T. denitrificans-CdS after irradiation was significantly upregulated. The photoexcited electrons acted as the dominant electron sources for NO(3)(-)reduction by T. denitrificans-CdS. This study provides the first proof of concept for sustainable and low-cost autotrophic denitrification to generate N2O driven by light. The findings also have strong implications for sustainable environmental management because the sunlight-triggered denitrification reaction driven by nonphototrophic microorganisms may widely occur in nature, particularly in a semiconductive mineral-enriched aqueous environment.
2019-08-26T14:19:50Z
2019-08-26T14:19:50Z
2019-06
Article - Refereed
0160-4120
http://hdl.handle.net/10919/93258
https://doi.org/10.1016/j.envint.2019.03.045
127
30954721
1873-6750
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
oai:vtechworks.lib.vt.edu:10919/1181572024-03-15T13:35:58Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539col_10919_70873col_10919_23748
The sanitary sewer unit hydrograph model: A comprehensive tool for wastewater flow modeling and inflow-infiltration simulations
Perez, Gabriel
Gomez-Velez, Jesus D.
Grant, Stanley B.
Base wastewater flow
Groundwater infiltration
Runoff derived infiltration and inflow
Sewer network
Unit hydrograph
Weighted width function
Sanitary sewer systems are critical urban water infrastructure that protect both human and environmental health. Their design, operation, and monitoring require novel modeling techniques that capture dominant processes while allowing for computationally efficient simulations. Open water flow in sewers and rivers are intrinsically similar processes. With this in mind, we formulated a new parsimonious model inspired by the Width Function Instantaneous Unit Hydrograph (WFIUH) approach, widely used to predict rainfall-runoff relationships in watersheds, to a sanitary sewer system consisting of nearly 10,000 sewer conduits and 120,000 residential and commercial sewage connections in Northern Virginia, U.S.A. Model predictions for the three primary components of sanitary flow, including Base Wastewater Flow (BWF), Groundwater Infiltration (GWI), and Runoff Derived Infiltration and Inflow (RDII), compare favorably with the more computationally demanding industry-standard Storm Water Management Model (SWMM). This novel application of the WFIUH modeling framework should support a number of critical water quality endpoints, including (i) sewer hydrograph separation through the quantification of BWF, GWI, and RDII outflows, (ii) evaluation of the impact of new urban developments on sewage flow dynamics, (iii) monitoring and mitigation of sanitary sewer overflows, and (iv) design and interpretation of wastewater surveillance studies.
2024-02-26T14:51:53Z
2024-02-26T14:51:53Z
2023-12-08
Article - Refereed
0043-1354
S0043-1354(23)01437-9 (PII)
https://hdl.handle.net/10919/118157
https://doi.org/10.1016/j.watres.2023.120997
249
Grant, Stanley [0000-0001-6221-7211]
38091697
1879-2448
en
https://www.ncbi.nlm.nih.gov/pubmed/38091697
http://creativecommons.org/licenses/by-nc/4.0/
Creative Commons Attribution-NonCommercial 4.0 International
Elsevier
oai:vtechworks.lib.vt.edu:10919/1031912023-06-23T15:22:49Zcom_10919_23747com_10919_5539com_10919_79468com_10919_78628col_10919_23748col_10919_79481
Experimental Investigation of Sound Transmission Loss in Concrete Containing Recycled Rubber Crumbs
Chalangaran, Navid
Farzampour, Alireza
Paslar, Nima
Fatemi, Hadi
Civil and Environmental Engineering
Concrete
Recycled Rubber Crumbs
Sound transmission Loss
Mix Design
Impedance Tube
This study represents procedures and material to improve sound transmission loss through concrete without having any significant effects on mechanical properties. To prevent noise pollution damaging effects, and for reducing the transmission of the noises from streets to residential buildings, sound absorbing materials could be effectively produced. For this purpose, a number of several mixture designs have been investigated in this study to reduce the sound transmission through concrete, including control sample and three mixtures with recycled rubber with sizes of from 1mm up to 3 mm to limit the sound transmission. The rubber is used as a replacement of 5, 10, and 15 percent of sand aggregates. First, 7, 14 and 28-day strengths of the concrete have been measured. Subsequently, the sound transmission losses through the samples have been measured at the range of 63 Hz up to 6300 Hz by using impedance tube and the transfer function. The results show specimens containing 15% fine-grained crumbs, the loss of sound transmission were up to 190%, and for samples with 15% coarse-grained rubber, the loss of sound transmission were up to 228%, respectively. It is shown that concrete with recycled rubber crumbs could effectively improve environmental noise absorption.
2021-05-05T13:56:47Z
2021-05-05T13:56:47Z
2021-05-15
Article
http://hdl.handle.net/10919/103191
en
Technopress
oai:vtechworks.lib.vt.edu:10919/958252021-11-10T15:17:19Zcom_10919_23747com_10919_5539col_10919_23748
Urban influence on the concentration and composition of submicron particulate matter in central Amazonia
de Sa, Suzane S.
Palm, Brett B.
Campuzano-Jost, Pedro
Day, Douglas A.
Hu, Weiwei
Isaacman-VanWertz, Gabriel
Yee, Lindsay D.
Brito, Joel
Carbone, Samara
Ribeiro, Igor O.
Cirino, Glauber G.
Liu, Yingjun
Thalman, Ryan
Sedlacek, Arthur
Funk, Aaron
Schumacher, Courtney
Shilling, John E.
Schneider, Johannes
Artaxo, Paulo
Goldstein, Allen H.
Souza, Rodrigo A. F.
Wang, Jian
McKinney, Karena A.
Barbosa, Henrique M. J.
Alexander, M. Lizabeth
Jimenez, Jose L.
Martin, Scot T.
Civil and Environmental Engineering
An understanding of how anthropogenic emissions affect the concentrations and composition of airborne particulate matter (PM) is fundamental to quantifying the influence of human activities on climate and air quality. The central Amazon Basin, especially around the city of Manaus, Brazil, has experienced rapid changes in the past decades due to ongoing urbanization. Herein, changes in the concentration and composition of submicron PM due to pollution downwind of the Manaus metropolitan region are reported as part of the GoAmazon2014/5 experiment. A high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a suite of other gas-and particle-phase instruments were deployed at the "T3" research site, 70 km downwind of Manaus, during the wet season. At this site, organic components represented 79 +/- 7% of the non-refractory PM1 mass concentration on average, which was in the same range as several upwind sites. However, the organic PM1 was considerably more oxidized at T3 compared to upwind measurements. Positive-matrix factorization (PMF) was applied to the time series of organic mass spectra collected at the T3 site, yielding three factors representing secondary processes (73 +/- 15% of total organic mass concentration) and three factors representing primary anthropogenic emissions (27 +/- 15 %). Fuzzy c-means clustering (FCM) was applied to the afternoon time series of concentrations of NOy, ozone, total particle number, black carbon, and sulfate. Four clusters were identified and characterized by distinct air mass origins and particle compositions. Two clusters, Bkgd-1 and Bkgd2, were associated with background conditions. Bkgd-1 appeared to represent near-field atmospheric PM production and oxidation of a day or less. Bkgd-2 appeared to represent material transported and oxidized for two or more days, often with out-of-basin contributions. Two other clusters, Pol-1 and Pol-2, represented the Manaus influence, one apparently associated with the northern region of Manaus and the other with the southern region of the city. A composite of the PMF and FCM analyses provided insights into the anthropogenic effects on PM concentration and composition. The increase in mass concentration of submicron PM ranged from 25% to 200% under polluted compared with background conditions, including contributions from both primary and secondary PM. Furthermore, a comparison of PMF factor loadings for different clusters suggested a shift in the pathways of PM production under polluted conditions. Nitrogen oxides may have played a critical role in these shifts. Increased concentrations of nitrogen oxides can shift pathways of PM production from HO2-dominant to NO-dominant as well as increase the concentrations of oxidants in the atmosphere. Consequently, the oxidation of biogenic and anthropogenic precursor gases as well as the oxidative processing of preexisting atmospheric PM can be accelerated. This combined set of results demonstrates the susceptibility of atmospheric chemistry, air quality, and associated climate forcing to anthropogenic perturbations over tropical forests.
2019-11-21T14:35:33Z
2019-11-21T14:35:33Z
2018-08-23
Article - Refereed
1680-7316
http://hdl.handle.net/10919/95825
https://doi.org/10.5194/acp-18-12185-2018
18
16
1680-7324
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
European Geophysical Union
oai:vtechworks.lib.vt.edu:10919/994562023-06-23T15:22:48Zcom_10919_78629com_10919_78628com_10919_23747com_10919_5539col_10919_78630col_10919_23748
Transmission of SARS-CoV-2 by inhalation of respiratory aerosol in the Skagit Valley Chorale superspreading event
Miller, Shelly
Nazaroff, William W.
Jimenez, Jose L.
Boerstra, Atze
Buonnano, Giorgio
Dancer, Stephanie J.
Kurnitski, Jarek
Marr, Linsey C.
Morawska, Lidia
Noakes, Catherine
Civil and Environmental Engineering
aerosol transmission
infectious disease
ventilation
virus
pandemic
risk
During the 2020 COVID-19 pandemic, an outbreak occurred following attendance of a symptomatic index case at a regular weekly rehearsal on 10 March of the Skagit Valley Chorale (SVC). After that rehearsal, 53 members of the SVC among 61 in attendance were confirmed or strongly suspected to have contracted COVID-19 and two died. Transmission by the airborne route is likely. It is vital to identify features of cases such as this so as to better understand the factors that promote superspreading events. Based on a conditional assumption that transmission during this outbreak was by inhalation of respiratory aerosol, we use the available evidence to infer the emission rate of airborne infectious quanta from the primary source. We also explore how the risk of infection would vary with several influential factors: the rates of removal of respiratory aerosol by ventilation; deposition onto surfaces; and viral decay. The results indicate an emission rate of the order of a thousand quanta per hour (mean [interquartile range] for this event = 970 [680-1190] quanta per hour) and demonstrate that the risk of infection is modulated by ventilation conditions, occupant density, and duration of shared presence with an infectious individual.
2020-07-31T13:33:54Z
2020-07-31T13:33:54Z
2020-06-15
Article
http://hdl.handle.net/10919/99456
https://doi.org/10.1101/2020.06.15.20132027
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
medRxiv
oai:vtechworks.lib.vt.edu:10919/930092023-11-29T16:17:30Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539com_10919_5524col_10919_78882col_10919_23748col_10919_89575
Feasibility Study for Using Piezoelectric-Based Weigh-In-Motion (WIM) System on Public Roadway
Xiong, Haocheng
Zhang, Yinning
Civil and Environmental Engineering
Virginia Tech Transportation Institute
Weigh-in-Motion
Piezoelectricity
Pavement Performance
Pavement Monitoring
Weigh-in-Motion system has been the primary selection of U.S. government agencies as the weighing enforcement for decades to protect the road pavement. In recent years, the number of trucks has increased by about 40% and in 2017, they travel 25% more annually than in 2016. The lack of the budget has slowed down the expansion of weighing enforcement to catch up with the growing workload of vehicle weighing. Unsupervised pavement section suffers more pavement damage and increased repairing cost. In this work, a piezoelectric material based WIM system (P-WIM) is developed. Such a system consists of several piezoelectric material disks that are capable of generating characteristic voltage output from passing vehicles. The axle loading of the vehicle can be determined by analyzing the voltage generated from the P-WIM. Compared to traditional WIM system, P-WIM requires nearly zero maintenance and costs 80% less on capital investment and less labor and effort to integrate. To evaluate the feasibility of this technology to serve as weighing enforcement on public roadways, prototype P-WIMs are fabricated and installed at a weigh station. The vehicle loading information provided by the weigh station is used to determine the force transmission percentage of the installed P-WIMs, which is an important parameter to determine the vehicles’ axle loading by generated voltage.
2019-08-09T12:23:21Z
2019-08-09T12:23:21Z
2019-07-31
2019-08-09T08:01:22Z
Article - Refereed
Xiong, H.; Zhang, Y. Feasibility Study for Using Piezoelectric-Based Weigh-In-Motion (WIM) System on Public Roadway. Appl. Sci. 2019, 9, 3098.
http://hdl.handle.net/10919/93009
https://doi.org/10.3390/app9153098
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/998412020-10-15T20:33:58Zcom_10919_78629com_10919_78628com_10919_23747com_10919_5539col_10919_78630col_10919_23748
Tracking reduction of water lead levels in two homes during the Flint Federal Emergency
Mantha, Anurag
Tang, Min
Pieper, Kelsey J.
Parks, Jeffrey L.
Edwards, Marc A.
Civil and Environmental Engineering
Sequential sampling
Profiling
Lead in water
Corrosion control
Premise plumbing
A Federal Emergency was declared in Flint, MI, on January 16, 2016, 18-months after a switch to Flint River source water without phosphate corrosion control. Remedial actions to resolve the corresponding lead in water crisis included reconnection to the original Lake Huron source water with orthophosphate, implementing enhanced corrosion control by dosing extra orthophosphate, a "Flush for Flint" program to help clean out loose leaded sediment from service lines and premise plumbing, and eventually lead service line replacement. Independent sampling over a period of 37 months (January 2016eFebruary 2019) was conducted by the United States Environmental Protection Agency and Virginia Tech to evaluate possible human exposure via normal flow (2e3 L/min) sampling at the cold kitchen tap, and to examine the status of loose deposits from the service line and the premise plumbing via high-velocity flushing (12e13 L/min) from the hose bib. The sampling results indicated that high lead in water persisted for more than a year in two Flint homes due to a large reservoir of lead deposits. The effects of a large reservoir of loose lead deposits persisted until the lead service line was completely removed in these two anomalous homes. As water conservation efforts are implemented in many areas of the country, problems with mobile lead reservoirs in service lines are likely to pose a human health risk.
2020-08-25T12:35:36Z
2020-08-25T12:35:36Z
2020-05-01
Article - Refereed
UNSP 100047
http://hdl.handle.net/10919/99841
https://doi.org/10.1016/j.wroa.2020.100047
7
32195459
2589-9147
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
oai:vtechworks.lib.vt.edu:10919/803922023-06-23T15:22:54Zcom_10919_78629com_10919_78628com_10919_23747com_10919_5539col_10919_79980col_10919_23748
Dynamic Travel Time Prediction using Pattern Recognition
Chen, Hao
Rakha, Hesham A.
McGhee, Catherine C.
Civil and Environmental Engineering
Travel-time information is an essential part of Advanced Traveler Information Systems (ATISs) and Advanced Traffic Management Systems (ATMSs). A key component of these systems is the prediction of travel times. From the perspective of travelers such information may assist in making better route choice and departure time decisions. For transportation agencies these data provide criteria with which to better manage and control traffic to reduce congestion. This study proposes a dynamic travel time prediction algorithm that matches current traffic patterns to historical data. Unlike previous approaches that use travel time as the control variable, the approach uses the temporal-spatial traffic state evolution to match traffic states and predict travel times. The approach first identifies candidate historical time intervals by matching real-time traffic state data against historical data for use in prediction purposes. Subsequently, the selected candidates are used to predict the temporal-spatial evolution of traffic. Lastly, dynamic travel times are constructed using the identified candidate historical data. The proposed algorithm is tested on a 37-mile freeway segment from Newport News to Virginia Beach along the I-64 and I-264 freeways using historical INRIX data. The prediction results indicate that the proposed method produces predictions that are more accurate than the state-of-the-art K-Nearest Neighbor methods reducing the prediction error by 15 percent to less than 3 minutes on a 50-minute trip.
2017-11-15T15:35:16Z
2017-11-15T15:35:16Z
2013
Conference proceeding
http://hdl.handle.net/10919/80392
en
20th World Congress on Intelligent Transportation Systems
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
TU Delft
oai:vtechworks.lib.vt.edu:10919/973452020-10-15T20:34:49Zcom_10919_78629com_10919_78628com_10919_23747com_10919_5539col_10919_78630col_10919_23748
Water Resources Adaptation to Climate and Demand Change in the Potomac River
Stagge, James H.
Moglen, Glenn E.
Civil and Environmental Engineering
Water resources management
Optimization
Climate change adaptation
Drought
The effects of climate change are increasingly considered in conjunction with changes in water demand and reservoir sedimentation in forecasts of water supply vulnerability. Here, the relative effects of these factors are evaluated for the Washington, DC metropolitan area water supply for the near (2010-2039), intermediate (2040-2069), and distant (2070-2099) future by repeated water resources model simulations. This system poses water management challenges because of long water-delivery travel times that increase uncertainty, multiple water jurisdictions that constrain potential decisions, and future scenarios that simultaneously increase demand and decrease water supply during the critical summer period. Adaptation strategies were developed for the system using a multiobjective evolutionary algorithm. Optimized reservoir management policies were compared using six distinct objectives ranging from reservoir storage to environmental and recreational benefits. Simulations of future conditions show water stress increasing with time. Reservoir sedimentation is projected to more than double (114% increase) the severity of reservoir storage failures by 2040. Increases in water demand and climate change are projected to further stress the system, causing longer periods of low flow and a loss of recreational reservoir storage. The adoption of optimized rules mitigates some of these effects, most notably returning simulations of 2070-2099 climate to near historical levels. Modifying the balance between upstream and downstream reservoirs improved storage penalties by 20.7% and flowby penalties by 50%. Changing triggers for shifting load to off-line reservoirs improved flowby (8.3%) and environmental (4.1%) penalties slightly, whereas changing demand restriction triggers provided only moderate improvements, but with few adverse effects. (C) 2017 American Society of Civil Engineers.
2020-03-18T12:10:28Z
2020-03-18T12:10:28Z
2017-11
Article - Refereed
1084-0699
4017050
http://hdl.handle.net/10919/97345
https://doi.org/10.1061/(ASCE)HE.1943-5584.0001579
22
11
1943-5584
en
http://creativecommons.org/publicdomain/zero/1.0/
Creative Commons CC0 1.0 Universal Public Domain Dedication
oai:vtechworks.lib.vt.edu:10919/1097472022-04-27T07:11:45Zcom_10919_23747com_10919_5539col_10919_23748
The environmental footprint of data centers in the United States
Siddik, Md Abu Bakar
Shehabi, Arman
Marston, Landon T.
water scarcity
data center
water footprint
carbon footprint
water-energy nexus
Much of the world's data are stored, managed, and distributed by data centers. Data centers require a tremendous amount of energy to operate, accounting for around 1.8% of electricity use in the United States. Large amounts of water are also required to operate data centers, both directly for liquid cooling and indirectly to produce electricity. For the first time, we calculate spatially-detailed carbon and water footprints of data centers operating within the United States, which is home to around one-quarter of all data center servers globally. Our bottom-up approach reveals one-fifth of data center servers direct water footprint comes from moderately to highly water stressed watersheds, while nearly half of servers are fully or partially powered by power plants located within water stressed regions. Approximately 0.5% of total US greenhouse gas emissions are attributed to data centers. We investigate tradeoffs and synergies between data center's water and energy utilization by strategically locating data centers in areas of the country that will minimize one or more environmental footprints. Our study quantifies the environmental implications behind our data creation and storage and shows a path to decrease the environmental footprint of our increasing digital footprint.
2022-04-26T12:55:32Z
2022-04-26T12:55:32Z
2021-06
Article - Refereed
1748-9326
64017
http://hdl.handle.net/10919/109747
https://doi.org/10.1088/1748-9326/abfba1
16
6
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
United States
oai:vtechworks.lib.vt.edu:10919/1121222022-10-11T07:13:55Zcom_10919_23747com_10919_5539col_10919_23748
Effects of Shell Hash on Friction Angles of Surficial Seafloor Sediments near Oysters
Consolvo, Samuel T.
Stark, Nina
Castellanos, Bernardo
Castro-Bolinaga, Celso F.
Hall, Steven
Massey, Grace
shear-strength
particle-shape
quartz sand
scour
consequences
prediction
delta-c-13
signatures
stability
density
Oysters are hypothesized to affect the shear strength of nearby surficial seafloor sediment as fragments of oyster shells (shell hash) are typically more angular relative to sand particles alone, among other differences. Resistance to shearing is well characterized by the friction angle, which is estimated in this study from vacuum triaxial laboratory and portable free-fall penetrometer field tests. Friction angles of sediment with shell hash were higher relative to those of sediment without shell hash (via hydrochloric acid treatment) on average by about 19% (36.0 degrees-30.2 degrees, respectively). Triaxial confining pressures ranged between 2.1 and 49.0 kPa to simulate subtidal and intertidal aquatic conditions. Regularity (average of particle roundness and sphericity) values of sediment samples with shell hash were found to be less than those of samples without by about 6% (0.66 and 0.70, respectively), which indicates the particle shapes of the former are, overall, more angular and less spherical. Further study and methodology improvements are needed to decrease the approximate 9 degrees friction angle discrepancy estimated from field- and laboratory-based tests. Knowing oysters have the potential to increase sediment shearing resistance helps establish a pathway of how shellfish colonies may contribute to mitigating surficial erosion around coastal infrastructure.
2022-10-10T15:00:10Z
2022-10-10T15:00:10Z
2022-09-01
Article - Refereed
0733-950X
4022015
http://hdl.handle.net/10919/112122
https://doi.org/10.1061/(ASCE)WW.1943-5460.0000716
148
5
1943-5460
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
ASCE
oai:vtechworks.lib.vt.edu:10919/1052872022-04-08T04:37:40Zcom_10919_78629com_10919_78628com_10919_23747com_10919_5539com_10919_24251com_10919_5555col_10919_78630col_10919_23748col_10919_24320
How did we get here: what are droplets and aerosols and how far do they go? A historical perspective on the transmission of respiratory infectious diseases
Randall, Katherine
Ewing, E. Thomas
Marr, Linsey C.
Jiminez, J. L.
Bourouiba, Lydia
respiratory diseases
public health
aerosols
droplets
historical
transmission
The COVID-19 pandemic has exposed major gaps in our understanding of the transmission of viruses through the air. These gaps slowed recognition of airborne transmission of the disease, contributed to muddled public health policies and impeded clear messaging on how best to slow transmission of COVID-19. In particular, current recommendations have been based on four tenets: (i) respiratory disease transmission routes can be viewed mostly in a binary manner of ‘droplets’ versus ‘aerosols’; (ii) this dichotomy depends on droplet size alone; (iii) the cut-off size between these routes of transmission is 5 µm; and (iv) there is a dichotomy in the distance at which transmission by each route is relevant. Yet, a relationship between these assertions is not supported by current scientific knowledge. Here, we revisit the historical foundation of these notions, and how they became entangled from the 1800s to today, with a complex interplay among various fields of science and medicine. This journey into the past highlights potential solutions for better collaboration and integration of scientific results into practice for building a more resilient society with more sound, far-sighted and effective public health policies.
2021-10-13T16:34:22Z
2021-10-13T16:34:22Z
2021-10-12
Article - Refereed
Randall K, Ewing ET, Marr LC, Jimenez JL, Bourouiba L. 2021 How did we get here: what are droplets and aerosols and how far do they go? A historical perspective on the transmission of respiratory infectious diseases. Interface Focus 11: 20210049. https://doi.org/10.1098/rsfs.2021.0049
http://hdl.handle.net/10919/105287
https://doi.org/10.1098/rsfs.2021.0049
11
6
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Royal Society
oai:vtechworks.lib.vt.edu:10919/1156862023-07-09T07:12:17Zcom_10919_23747com_10919_5539col_10919_23748
Investigations on The Structural Behavior of Steel Plate Shear Walls with Partially Interconnected Infill Plates
Paslar, Nima
Farzampour, Alireza
Chalangaran, Navid
Mansouri, Iman
Wan Hu, Jong
Structural fuses, Finite element analysis, Computational programming, New generation of lateral resisting systems
Steel plate shear walls are considered an effective lateral load-resisting system widely used in space-constrained high-rise buildings. Steel plate shear walls could improve several structural parameters such as strength, energy absorption, and stiffness. Recently, there is a tendency to have limited connection between the infill plate and boundary elements to prevent significant direct demands on columns, and possible brittle modes of behavior leading to the economical design of various structural elements. However, previous studies showed that the absence of the interconnection between infill plate and columns in steel plate shear walls with beam-connected systems could reduce the performance of the system significantly. In the present study, procedures to improve the performance of the steel plate shear walls with limited infill plate interconnections with the boundary elements are provided. Subsequently, computational steel plate shear wall models, with and without boundary infill plate stiffeners and different widths of the infill plate have been investigated after fully validating the computational modeling methodology to find efficient procedures for eliminating the lack of interconnections. The results show that utilizing boundary stiffeners increased ultimate strength, energy dissipation and stiffness by 15%, 20%, and 24% on average. Although boundary stiffeners cannot fully control the out-of-plane displacements of the infill plate, they would be useful in improving the formation of tension field actions. Furthermore, it is shown that the width of the infill plate and boundary stiffeners are the key factors in the performance of the system.
2023-07-08T14:57:03Z
2023-07-08T14:57:03Z
2023-07-08
Article
http://hdl.handle.net/10919/115686
12th International Symposium on Steel Structures, November 8-11, 2023, Jeju, Korea
oai:vtechworks.lib.vt.edu:10919/735282023-06-23T15:22:56Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539col_10919_70873col_10919_23748
Energy consumption of water recovery from wastewater in a submerged forward osmosis system using commercial liquid fertilizer as a draw solute
Xiang, Xiaoxue
Zou, Shiqiang
He, Zhen
Civil and Environmental Engineering
2016-11-29T16:05:36Z
2016-11-29T16:05:36Z
2017-03-01
Article - Refereed
1383-5866
http://hdl.handle.net/10919/73528
https://doi.org/10.1016/j.seppur.2016.10.052
174
en
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
oai:vtechworks.lib.vt.edu:10919/1080372022-02-26T15:58:37Zcom_10919_78629com_10919_78628com_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78630col_10919_18629col_10919_23748
Long-read metagenomic sequencing reveals shifts in associations of antibiotic resistance genes with mobile genetic elements from sewage to activated sludge
Dai, Dongjuan
Brown, Connor L.
Bürgmann, Helmut
Larsson, D. G. J.
Nambi, Indumathi
Zhang, Tong
Flach, Carl-Fredrik
Pruden, Amy
Vikesland, Peter J.
Background
There is concern that the microbially rich activated sludge environment of wastewater treatment plants (WWTPs) may contribute to the dissemination of antibiotic resistance genes (ARGs). We applied long-read (nanopore) sequencing to profile ARGs and their neighboring genes to illuminate their fate in the activated sludge treatment by comparing their abundance, genetic locations, mobility potential, and bacterial hosts within activated sludge relative to those in influent sewage across five WWTPs from three continents.
Results
The abundances (gene copies per Gb of reads, aka gc/Gb) of all ARGs and those carried by putative pathogens decreased 75–90% from influent sewage (192-605 gc/Gb) to activated sludge (31-62 gc/Gb) at all five WWTPs. Long reads enabled quantification of the percent abundance of ARGs with mobility potential (i.e., located on plasmids or co-located with other mobile genetic elements (MGEs)). The abundance of plasmid-associated ARGs decreased at four of five WWTPs (from 40–73 to 31–68%), and ARGs co-located with transposable, integrative, and conjugative element hallmark genes showed similar trends. Most ARG-associated elements decreased 0.35–13.52% while integrative and transposable elements displayed slight increases at two WWTPs (1.4–2.4%). While resistome and taxonomic compositions both shifted significantly, host phyla for chromosomal ARG classes remained relatively consistent, indicating vertical gene transfer via active biomass growth in activated sludge as the key pathway of chromosomal ARG dissemination.
Conclusions
Overall, our results suggest that the activated sludge process acted as a barrier against the proliferation of most ARGs, while those that persisted or increased warrant further attention.
2022-01-31T12:44:51Z
2022-01-31T12:44:51Z
2022-01-29
2022-01-30T04:14:47Z
Article - Refereed
Microbiome. 2022 Jan 29;10(1):20
http://hdl.handle.net/10919/108037
https://doi.org/10.1186/s40168-021-01216-5
en
http://creativecommons.org/licenses/by/4.0/
The Author(s)
Creative Commons Attribution 4.0 International
oai:vtechworks.lib.vt.edu:10919/1143522023-04-07T07:12:00Zcom_10919_11363com_10919_5539com_10919_23747com_10919_91436com_10919_5532col_10919_23164col_10919_23748col_10919_97229
Sensing atmospheric flows in aquatic environments using a multirotor small uncrewed aircraft system (sUAS)
Gonzalez-Rocha, Javier
Bilyeu, Landon
Ross, Shane D.
Foroutan, Hosein
Jacquemin, Stephen J.
Ault, Andrew P.
Schmale, David G. III
Unmanned aircraft
wind estimation
New wind sensing technologies are needed to measure atmospheric flows in aquatic environments where hazardous agents may be present and conventional atmospheric sensors are difficult to deploy. Here, we present the application of model-based multirotor sUAS (small uncrewed aircraft system) wind estimation to measure atmospheric flow variations in aquatic environments. Thirty-two sUAS flights were conducted at Grand Lake St. Marys (GLSM), Ohio in August, 2019 to characterize differences in wind profiles (wind speed and wind direction) across onshore and offshore (over the lake) locations 80 m apart. A harmful algal bloom was present in GLSM during the experiment. Fourteen calibration flights were conducted at the same site to validate multirotor sUAS wind estimates hovering next to a sonic anemometer (SA) installed 13 m above ground level. Forty-seven calibration profiles were performed in Blacksburg, Virginia on June 30th, 2020 to validate multirotor sUAS wind estimates obtained in steady ascending vertical flight next to a SoDAR wind profiler. Differences between onshore and offshore wind speed measurements at GLSM increased from morning to afternoon on each day of experiments. Flights performed next to SA and SoDAR instruments also demonstrated multirotor sUAS estimates of wind velocity components u and v to have mean absolute error values of 0.4 m s(-1) and 0.3 m s(-1) (hovering) and 1.2 m s(-1) and 1.5 m s(-1) (ascending), respectively. Overall, our findings support further development of multirotor sUAS capabilities for resolving atmospheric flows in aquatic environments.
2023-04-06T17:27:06Z
2023-04-06T17:27:06Z
2023-01
Article - Refereed
http://hdl.handle.net/10919/114352
https://doi.org/10.1039/d2ea00042c
2634-3606
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Royal Society Chemistry
oai:vtechworks.lib.vt.edu:10919/1137102023-02-08T08:12:46Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539col_10919_70873col_10919_23748
Seasonal Fluctuations in Nitrate Levels Can Trigger Lead Solder Corrosion Problems in Drinking Water
Lopez, Kathryn G.
Xiao, Jinghua
Crockett, Christopher
Lytle, Christian
Grubbs, Haley
Edwards, Marc A.
After a utility switched its source water from ground to surface water in 2017, first draw water lead levels spiked due to increased lead solder corrosion that could not be explained by existing knowledge. When lead release was not adequately reduced with a 90:10 orthophosphate/polyphosphate corrosion inhibitor blend or even high levels of 100% orthophosphate, an in-depth investigation of possible causes revealed a strong correlation between 90th percentile lead and seasonal fluctuations in surface water nitrate levels. Complementary bench-scale studies that tested new copper coupons with lead solder and harvested pipes from a worst case home verified a strong relationship between nitrate and elevated lead. Lead release in the presence of nitrate became increasingly erratic with time, resulting in the spalling of large lead solder particulates up to 7 mm in length into the water. Lead levels were occasionally >1000 ppb in homes and >100000 ppb in the bench experiments with harvested pipe. Orthophosphate was unable to sufficiently reduce lead levels below the action level during periods with high nitrate levels in the bench studies. Water utilities and regulators should proactively consider possible unintended consequences of higher nitrate levels on lead release when changing source waters or during seasonal runoff events.
2023-02-07T19:30:55Z
2023-02-07T19:30:55Z
2023-01-10
2023-02-07T17:20:08Z
Article - Refereed
2328-8930
PMC9835880
http://hdl.handle.net/10919/113710
https://doi.org/10.1021/acs.estlett.2c00581
10
1
Edwards, Marc [0000-0002-1889-1193]
36643386
2328-8930
en
https://www.ncbi.nlm.nih.gov/pubmed/36643386
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
American Chemical Society
oai:vtechworks.lib.vt.edu:10919/943342022-02-25T02:39:53Zcom_10919_23747com_10919_5539col_10919_23748
An integrated shear-wave velocity model for the Groningen gas field, The Netherlands
Kruiver, Pauline P.
van Dedem, Ewoud
Romijn, Remco
de Lange, Ger
Korff, Mandy
Stafleu, Jan
Gunnink, Jan L.
Rodriguez-Marek, Adrian
Bommer, Julian J.
van Elk, Jan
Doornhof, Dirk
Civil and Environmental Engineering
Shear-wave velocity
Site response analysis
Geology
Randomisation
Surface-wave inversion
Microzonation
A regional shear-wave velocity (V-S) model has been developed for the Groningen gas field in the Netherlands as the basis for seismic microzonation of an area of more than 1000 km(2). The V-S model, extending to a depth of almost 1 km, is an essential input to the modelling of hazard and risk due to induced earthquakes in the region. The detailed V-S profiles are constructed from a novel combination of three data sets covering different, partially overlapping depth ranges. The uppermost 50 m of the V-S profiles are obtained from a high-resolution geological model with representative V-S values assigned to the sediments. Field measurements of V-S were used to derive representative V-S values for the different types of sediments. The profiles from 50 to 120 m are obtained from inversion of surface waves recorded (as noise) during deep seismic reflection profiling of the gas reservoir. The deepest part of the profiles is obtained from sonic logging and V-P-V-S relationships based on measurements in deep boreholes. Criteria were established for the splicing of the three portions to generate continuous models over the entire depth range for use in site response calculations, for which an elastic half-space is assumed to exist below a clear stratigraphic boundary and impedance contrast encountered at about 800 m depth. In order to facilitate fully probabilistic site response analyses, a scheme for the randomisation of the V-S profiles is implemented.
2019-10-03T12:37:21Z
2019-10-03T12:37:21Z
2017-09
Article - Refereed
1570-761X
http://hdl.handle.net/10919/94334
https://doi.org/10.1007/s10518-017-0105-y
15
9
1573-1456
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
oai:vtechworks.lib.vt.edu:10919/649782023-11-29T19:08:00Zcom_10919_78629com_10919_78628com_10919_5540com_10919_23747com_10919_5539col_10919_79524col_10919_71752col_10919_23748
Patterns and Limitations of Urban Human Mobility Resilience under the Influence of Multiple Types of Natural Disaster
Wang, Qi
Taylor, John E.
Braunstein, Lidia Adriana
Civil and Environmental Engineering
Human mobility
Natural disasters
Twitter
Urban areas
Cell phones
Telecommunications
Wildfires
Behavior
Natural disasters pose serious threats to large urban areas, therefore understanding and predicting human movements is critical for evaluating a population’s vulnerability and resilience and developing plans for disaster evacuation, response and relief. However, only limited research has been conducted into the effect of natural disasters on human mobility. This study examines how natural disasters influence human mobility patterns in urban populations using individuals’ movement data collected from Twitter. We selected fifteen destructive cases across five types of natural disaster and analyzed the human movement data before, during, and after each event, comparing the perturbed and steady state movement data. The results suggest that the power-law can describe human mobility in most cases and that human mobility patterns observed in steady states are often correlated with those in perturbed states, highlighting their inherent resilience. However, the quantitative analysis shows that this resilience has its limits and can fail in more powerful natural disasters. The findings from this study will deepen our understanding of the interaction between urban dwellers and civil infrastructure, improve our ability to predict human movement patterns during natural disasters, and facilitate contingency planning by policymakers.
2016-03-23T17:00:03Z
2016-03-23T17:00:03Z
2016-01-28
Article - Refereed
Wang Q, Taylor JE. (2016). Patterns and Limitations of Urban Human Mobility Resilience under the Influence of Multiple Types of Natural Disaster. PLoS ONE 11(1): e0147299. doi:10.1371/journal.pone.0147299
1932-6203
Grant No. 1142379
http://hdl.handle.net/10919/64978
https://doi.org/10.1371/journal.pone.0147299
11
1
en
http://dx.doi.org/10.5061/dryad.88354
http://creativecommons.org/licenses/by/3.0/us/
Wang, Qi
Taylor, John E.
© 2016 Wang, Taylor. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Creative Commons Attribution 3.0 United States
Public Library of Science
oai:vtechworks.lib.vt.edu:10919/958272022-02-25T02:39:53Zcom_10919_23747com_10919_5539col_10919_23748
Secondary organic aerosol formation from ambient air in an oxidation flow reactor in central Amazonia
Palm, Brett B.
de Sa, Suzane S.
Day, Douglas A.
Campuzano-Jost, Pedro
Hu, Weiwei
Seco, Roger
Sjostedt, Steven J.
Park, Jeong-Hoo
Guenther, Alex B.
Kim, Saewung
Brito, Joel
Wurm, Florian
Artaxo, Paulo
Thalman, Ryan
Wang, Jian
Yee, Lindsay D.
Wernis, Rebecca A.
Isaacman-VanWertz, Gabriel
Goldstein, Allen H.
Liu, Yingjun
Springston, Stephen R.
Souza, Rodrigo
Newburn, Matt K.
Alexander, M. Lizabeth
Martin, Scot T.
Jimenez, Jose L.
Civil and Environmental Engineering
Secondary organic aerosol (SOA) formation from ambient air was studied using an oxidation flow reactor (OFR) coupled to an aerosol mass spectrometer (AMS) during both the wet and dry seasons at the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) field campaign. Measurements were made at two sites downwind of the city of Manaus, Brazil. Ambient air was oxidized in the OFR using variable concentrations of either OH or O-3, over ranges from hours to days (O-3) or weeks (OH) of equivalent atmospheric aging. The amount of SOA formed in the OFR ranged from 0 to as much as 10 mu g m(-3), depending on the amount of SOA precursor gases in ambient air. Typically, more SOA was formed during nighttime than daytime, and more from OH than from O-3 oxidation. SOA yields of individual organic precursors under OFR conditions were measured by standard addition into ambient air and were confirmed to be consistent with published environmental chamber-derived SOA yields. Positive matrix factorization of organic aerosol (OA) after OH oxidation showed formation of typical oxidized OA factors and a loss of primary OA factors as OH aging increased. After OH oxidation in the OFR, the hygroscopicity of the OA increased with increasing elemental O : C up to O : C similar to 1.0, and then decreased as O : C increased further. Possible reasons for this decrease are discussed. The measured SOA formation was compared to the amount predicted from the concentrations of measured ambient SOA precursors and their SOA yields. While measured ambient precursors were sufficient to explain the amount of SOA formed from O-3, they could only explain 10-50% of the SOA formed from OH. This is consistent with previous OFR studies, which showed that typically unmeasured semivolatile and intermediate volatility gases (that tend to lack C=C bonds) are present in ambient air and can explain such additional SOA formation. To investigate the sources of the unmeasured SOA-forming gases during this campaign, multilinear regression analysis was performed between measured SOA formation and the concentration of gas-phase tracers representing different precursor sources. The majority of SOA-forming gases present during both seasons were of biogenic origin. Urban sources also contributed substantially in both seasons, while biomass burning sources were more important during the dry season. This study enables a better understanding of SOA formation in environments with diverse emission sources.
2019-11-21T14:35:34Z
2019-11-21T14:35:34Z
2018-01-17
Article - Refereed
1680-7316
http://hdl.handle.net/10919/95827
https://doi.org/10.5194/acp-18-467-2018
18
1
1680-7324
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
European Geophysical Union
oai:vtechworks.lib.vt.edu:10919/775512023-06-23T15:22:54Zcom_10919_23747com_10919_5539col_10919_23748
Aggregation and sedimentation of magnetite nanoparticle clusters
Vikesland, Peter J.
Rebodos, R. L.
Bottero, J. Y.
Rose, J.
Masion, A.
Civil and Environmental Engineering
Institute for Critical Technology and Applied Science (ICTAS)
Duke University. Center for the Environmental Implications of Nanotechnology (CEINT)
International Center for the Environmental Implications of Nanotechnology (iCEINT)
Magnetite nanoparticles are redox active constituents of subsurface and corrosive environments. In this study, we characterized the aggregation and sedimentation behavior of well characterized magnetite nanoparticle clusters using dynamic light scattering (DLS), UV-vis-NIR spectroscopy, and small angle X-ray scattering (SAXS). Both unfunctionalized (NaOH-magnetite) and tetramethylammonium hydroxide (TMAOH-magnetite) surface functionalized nanoparticle clusters were employed. TMAOH-magnetite has a slightly smaller primary nanoparticle radius as determined by TEM (4 ± 0.7 nm vs. 5 ± 0.8 for NaOH-magnetite) and a smaller initial DLS determined cluster radius (<30 nm vs. 100–200 nm for NaOH-magnetite). Interestingly, in spite of its smaller initial nanoparticle cluster size, TMAOH-magnetite undergoes sedimentation more rapidly than NaOH-magnetite. This behavior is consistent with the more rapid aggregation of the smaller TMAOH-magnetite clusters as well as their lower fractal dimension, as determined by SAXS. This study illustrates that both nanoparticle cluster size and fractal dimension should be carefully considered when considering the environmental transport and fate of highly aggregated nanoparticles.
2017-05-01T06:42:17Z
2017-05-01T06:42:17Z
2016-03-24
Article - Refereed
2051-8153
http://hdl.handle.net/10919/77551
https://doi.org/10.1039/c5en00155b
3
3
2051-8161
en
Royal Society of Chemistry Gold Open Access - 2016
http://creativecommons.org/licenses/by-nc/3.0/
Vikesland, Peter J.
Rebodos, R. L.
Bottero, J. Y.
Rose, J.
Masion, A.
Creative Commons Attribution-NonCommercial 3.0 Unported
Royal Society of Chemistry
oai:vtechworks.lib.vt.edu:10919/1050682021-09-28T14:47:03Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78882col_10919_23748
Acoustic Emission Wave Velocity Measurement of Asphalt Mixture by Arbitrary Wave Method
Li, Jianfeng
Liu, Huifang
Wang, Wentao
Zhao, Kang
Ye, Zhoujing
Wang, Linbing
Civil & Environmental Engineering
The wave velocity of acoustic emission (AE) can reflect the properties of materials, the types of AE sources and the propagation characteristics of AE in materials. At the same time, the wave velocity of AE is also an important parameter in source location calculation by the time-difference method. In this paper, a new AE wave velocity measurement method, the arbitrary wave (AW) method, is proposed and designed to measure the AE wave velocity of an asphalt mixture. This method is compared with the pencil lead break (PLB) method and the automatic sensor test (AST) method. Through comparison and analysis, as a new wave velocity measurement method of AE, the AW method shows the following advantages: A continuous AE signal with small attenuation, no crosstalk and a fixed waveform can be obtained by the AW method, which is more advantageous to distinguish the first arrival time of the acoustic wave and calculate the wave velocity of AE more accurately; the AE signal measured by the AW method has the characteristics of a high frequency and large amplitude, which is easy to distinguish from the noise signal with the characteristics of a low frequency and small amplitude; and the dispersion of the AE wave velocity measured by the AW method is smaller, which is more suitable for the measurement of the AE wave velocity of an asphalt mixture.
2021-09-27T12:25:04Z
2021-09-27T12:25:04Z
2021-09-13
2021-09-25T23:33:01Z
Article - Refereed
Li, J.; Liu, H.; Wang, W.; Zhao, K.; Ye, Z.; Wang, L. Acoustic Emission Wave Velocity Measurement of Asphalt Mixture by Arbitrary Wave Method. Appl. Sci. 2021, 11, 8505.
http://hdl.handle.net/10919/105068
https://doi.org/10.3390/app11188505
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/1116712023-11-29T11:25:11Zcom_10919_23747com_10919_5539com_10919_19035com_10919_25796col_10919_23748col_10919_24290col_10919_25797
mobileOG-db: a Manually Curated Database of Protein Families Mediating the Life Cycle of Bacterial Mobile Genetic Elements
Brown, Connor L.
Mullet, James
Hindi, Fadi
Stoll, James E.
Gupta, Suraj
Choi, Minyoung
Keenum, Ishi M.
Vikesland, Peter J.
Pruden, Amy
Zhang, Liqing
Bacterial mobile genetic elements (MGEs) encode functional modules that perform both core and accessory functions for the element, the latter of which are often only transiently associated with the element. The presence of these accessory genes, which are often close homologs to primarily immobile genes, incur high rates of false positives and, therefore, limits the usability of these databases for MGE annotation. To overcome this limitation, we analyzed 10,776,849 protein sequences derived from eight MGE databases to compile a comprehensive set of 6,140 manually curated protein families that are linked to the “life cycle” (integration/excision, replication/recombination/repair, transfer, stability/transfer/defense, and phage-specific processes) of plasmids, phages, integrative, transposable, and conjugative elements. We overlay experimental information where available to create a tiered annotation scheme of high-quality annotations and annotations inferred exclusively through bioinformatic evidence. We additionally provide an MGE-class label for each entry (e.g., plasmid or integrative element), and assign to each entry a major and minor category. The resulting database, mobileOG-db (for mobile orthologous groups), comprises over 700,000 deduplicated sequences encompassing five major mobileOG categories and more than 50 minor categories, providing a structured language and interpretable basis for an array of MGE-centered analyses. mobileOG-db can be accessed at mobileogdb.flsi.cloud.vt.edu/, where users can select, refine, and analyze custom subsets of the dynamic mobilome.
2022-08-30T17:07:25Z
2022-08-30T17:07:25Z
2022-08-29
Article - Refereed
http://hdl.handle.net/10919/111671
https://doi.org/10.1128/aem.00991-22
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
American Society for Microbiology
oai:vtechworks.lib.vt.edu:10919/959852023-06-23T15:22:48Zcom_10919_23747com_10919_5539col_10919_23748
Inventory of Seismic Structural Evaluations, Performance Functions and Taxonomies for Buildings (INSSEPT)
Zaker Esteghamati, Mohsen
Lee, Jeonghyun
Musetich, Matthew
Flint, Madeleine M.
Sharifi Mood, Mahyar
Civil and Environmental Engineering
Seismic
Earthquake
PBEE
Fragility
Performance
Building
Structure
PSDA
Relational database of published performance-based earthquake engineering and probabilistic seismic demand analysis results for mid-rise buildings. The database schema is organized based on building taxonomy information and prioritizes structural engineering use cases including comparison of alternative structural systems in early building design and regional seismic portfolio risk analysis. Data provenance, use cases, and sample queries are available in the accompanying manual, as well as two interactive Jupyter notebooks. A full description of the data provenance and schema design is provided in a related manuscript: Zaker Esteghamati, M., Lee J., Musetich M., Flint M. M., `INSSEPT: An open-source relational database of seismic performance estimation to aid with early design of buildings.'
2019-12-13T21:23:35Z
2019-12-13T21:23:35Z
2019-11-25
Dataset
Manual
http://hdl.handle.net/10919/95985
https://doi.org/10.17603/ds2-k1g7-vg97
en
http://creativecommons.org/licenses/by-nc-sa/3.0/us/
Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States
DesignSafe-CI
oai:vtechworks.lib.vt.edu:10919/1180752024-03-15T15:26:55Zcom_10919_5com_10919_25799com_10919_102756com_10919_5532com_10919_23747com_10919_5539com_10919_18738com_10919_24230col_10919_70873col_10919_102757col_10919_23748col_10919_23145col_10919_24305
Portable, low-cost samplers for distributed sampling of atmospheric gases
Hurley, James
Caceres, Alejandra
McGlynn, Deborah
Tovillo, Mary
Pinar, Suzanne
Schuerch, Roger
Onufrieva, Ksenia
Isaacman-VanWertz, Gabriel
Volatile organic compounds (VOCs) contribute to air pollution both directly, as hazardous gases, and through their reactions with common atmospheric oxidants to produce ozone, particulate matter, and other hazardous air pollutants. There are enormous ranges of structures and reaction rates among VOCs, and consequently a need to accurately characterize the spatial and temporal distribution of individual identified compounds. Current VOC measurements are often made with complex, expensive instrumentation that provides high chemical detail, but is limited in its portability and requires high expense (e.g., mobile labs) for spatially resolved measurements. Alternatively, periodic collection of samples on cartridges is inexpensive but demands significant operator interaction that can limit possibilities for time-resolved measurements or distributed measurements across a spatial area. Thus, there is a need for simple, portable devices that can sample with limited operator presence to enable temporally and/or spatially resolved measurements. In this work, we describe new portable and programmable VOC samplers that enable simultaneous collection of samples across a spatially distributed network, validate their reproducibility, and demonstrate their utility. Validation experiments confirmed high precision between samplers as well as the ability of miniature ozone scrubbers to preserve reactive analytes collected on commercially available adsorbent gas sampling cartridges, supporting simultaneous field deployment across multiple locations. In indoor environments, 24-hour integrated samples demonstrate observable day-to-day variability, as well as variability across very short spatial scales (meters). The utility of the samplers was further demonstrated by locating outdoor point sources of analytes through the development of a new mapping approach that employs a group of the portable samplers and back projection techniques to assess a sampling area with higher resolution than stationary sampling. As with all gas sampling, the limits of detection depend on sampling times and the properties of sorbent and analyte. Limit of detection of the analytical system used in this work is on the order of nanograms, corresponding to mixing ratios of 1-10 pptv after one hour of sampling at the programmable flow rate of 50-250 sccm enabled by the developed system. The portable VOC samplers described and validated here provide a simple, low-cost sampling solution for spatially and/or temporally variable measurements of any organic gases that are collectable on currently available sampling media.
2024-02-21T14:49:12Z
2024-02-21T14:49:12Z
2023-10-13
Article - Refereed
https://hdl.handle.net/10919/118075
16
19
Schuerch, Roger [0000-0001-9075-8912]
Onufrieva, Ksenia [0000-0002-8424-850X]
Isaacman-VanWertz, Gabriel [0000-0002-3717-4798]
en
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
oai:vtechworks.lib.vt.edu:10919/750362023-06-23T15:22:58Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539col_10919_70873col_10919_23748
Effects of electron acceptors on removal of antibiotic resistant Escherichia coli, resistance genes and class 1 integrons under anaerobic conditions
Yuan, Heyang
Miller, Jennifer H.
Abu-Reesh, Ibrahim M.
Pruden, Amy
He, Zhen
Civil and Environmental Engineering
Environmental Sciences
Environmental Sciences & Ecology
Antibiotic resistant bacteria
Antibiotic resistant genes
Bioelectrochemical systems
Electron acceptors
WASTE-WATER TREATMENT
MICROBIAL FUEL-CELLS
TETRACYCLINE RESISTANCE
MOLECULAR SIGNATURES
DESALINATION CELLS
TREATMENT PLANTS
GROWTH-RATE
TECHNOLOGY
SYSTEMS
RIVER
Anaerobic biotechnologies can effectively remove antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs), but there is a need to better understand the mechanisms. Here we employ bioelectrochemical systems (BES) as a platform to investigate the fate of a native tetracycline and sulfonamide-resistant Escherichia coli strain and its ARGs. The E. coli strain carrying intI1, sulI and tet(E) was isolated from domestic wastewater and dosed into a tubular BES. The BES was first operated as a microbial fuel cell (MFC), with aeration in the cathode, which resulted in enhanced removal of E. coli and ARGs by ~ 2 log (i.e., order of magnitude) when switched from high current to open circuit operation mode. The BES was then operated as a microbial electrolysis cell (MEC) to exclude the effects of oxygen diffusion, and the removal of E. coli and ARGs during the open circuit configuration was again 1–2 log higher than that at high current mode. Significant correlations of E. coli vs. current (R2 = 0.73) and ARGs vs. E. coli (R2 ranged from 0.54 to 0.87), and the fact that the BES substrate contained no electron acceptors, implied that the persistence of the E. coli and its ARGs was determined by the availability of indigenous electron acceptors in the BES, i.e., the anode electrode or the electron shuttles generated by the exoelectrogens. Subsequent experiments with pure-culture tetracycline and sulfonamide-resistant E. coli being incubated in a two-chamber MEC and serum bottles demonstrated that the E. coli could survive by respiring anode electrode and/or electron shuttles released by exoelectrogens, and ARGs persisted with their host E. coli.
2017-02-14T21:52:18Z
2017-02-14T21:52:18Z
2016-11-01
Article - Refereed
0048-9697
http://hdl.handle.net/10919/75036
https://doi.org/10.1016/j.scitotenv.2016.07.002
569
en
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000382269000154&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=930d57c9ac61a043676db62af60056c1
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
Elsevier
oai:vtechworks.lib.vt.edu:10919/1009602023-11-29T19:08:07Zcom_10919_78629com_10919_78628com_10919_8195com_10919_25799com_10919_5540com_10919_23747com_10919_5539col_10919_78630col_10919_78882col_10919_71752col_10919_23748
Critical Review: Propensity of Premise Plumbing Pipe Materials to Enhance or Diminish Growth of Legionella and Other Opportunistic Pathogens
Cullom, Abraham C.
Martin, Rebekah L.
Song, Yang
Williams, Krista
Williams, Amanda
Pruden, Amy
Edwards, Marc A.
Civil and Environmental Engineering
non-tuberculous mycobacteria
Pseudomonas
Acinetobacter
amoebae
copper
iron
PEX
PVC
drinking water
disinfection
Growth of <i>Legionella pneumophila</i> and other opportunistic pathogens (OPs) in drinking water premise plumbing poses an increasing public health concern. Premise plumbing is constructed of a variety of materials, creating complex environments that vary chemically, microbiologically, spatially, and temporally in a manner likely to influence survival and growth of OPs. Here we systematically review the literature to critically examine the varied effects of common metallic (copper, iron) and plastic (PVC, cross-linked polyethylene (PEX)) pipe materials on factors influencing OP growth in drinking water, including nutrient availability, disinfectant levels, and the composition of the broader microbiome. Plastic pipes can leach organic carbon, but demonstrate a lower disinfectant demand and fewer water chemistry interactions. Iron pipes may provide OPs with nutrients directly or indirectly, exhibiting a high disinfectant demand and potential to form scales with high surface areas suitable for biofilm colonization. While copper pipes are known for their antimicrobial properties, evidence of their efficacy for OP control is inconsistent. Under some circumstances, copper’s interactions with premise plumbing water chemistry and resident microbes can encourage growth of OPs. Plumbing design, configuration, and operation can be manipulated to control such interactions and health outcomes. Influences of pipe materials on OP physiology should also be considered, including the possibility of influencing virulence and antibiotic resistance. In conclusion, all known pipe materials have a potential to either stimulate or inhibit OP growth, depending on the circumstances. This review delineates some of these circumstances and informs future research and guidance towards effective deployment of pipe materials for control of OPs.
2020-11-30T12:48:49Z
2020-11-30T12:48:49Z
2020-11-17
2020-11-26T14:08:10Z
Article - Refereed
Cullom, A.C.; Martin, R.L.; Song, Y.; Williams, K.; Williams, A.; Pruden, A.; Edwards, M.A. Critical Review: Propensity of Premise Plumbing Pipe Materials to Enhance or Diminish Growth of Legionella and Other Opportunistic Pathogens. Pathogens 2020, 9, 957.
http://hdl.handle.net/10919/100960
https://doi.org/10.3390/pathogens9110957
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/1006922023-06-23T15:22:48Zcom_10919_23747com_10919_5539col_10919_23748
Seismic behavior investigation of the steel multi-story moment frames with steel plate shear walls
Mansouri, Iman
Arabzadeh, Ali
Farzampour, Alireza
Hu, Jong Wan
steel plate shear wall
deflection amplification factor (cd)
moment frame
multi-story buildings
hysteretic behavior
Steel plate shear walls are recently used as efficient seismic lateral resisting systems. These lateral resistant structures are implemented to provide more strength, stiffness and ductility in limited space areas. In this study, the seismic behavior of the multi-story steel frames with steel plate shear walls are investigated for buildings with 4, 8, 12 and 16 stories using verified computational modeling platforms. Different number of steel moment bays with distinctive lengths are investigated to effectively determine the deflection amplification factor for low-rise and high-rise structures. Results showed that the dissipated energy in moment frames with steel plates are significantly related to the inside panel. It is shown that more than 50% of the dissipated energy under various ground motions is dissipated by the panel itself, and increasing the steel plate length leads to higher energy dissipation capability. The deflection amplification factor is studied in details for various verified parametric cases, and it is concluded that for a typical multi-story moment frame with steel plate shear walls, the amplification factor is 4.93 which is less than the recommended conservative values in the design codes. It is shown that the deflection amplification factor decreases if the height of the building increases, for which the frames with more than six stories would have less recommended deflection amplification factor. In addition, increasing the number of bays or decreasing the steel plate shear wall length leads to a reduction of the deflection amplification factor.
2020-10-25T12:38:14Z
2020-10-25T12:38:14Z
2020-10
Article
http://hdl.handle.net/10919/100692
10.12989/scs.2020.37.1.091
37
1
en
http://creativecommons.org/licenses/by-sa/4.0/
Creative Commons Attribution-ShareAlike 4.0 International
Techno Press
oai:vtechworks.lib.vt.edu:10919/1054132022-02-25T02:39:53Zcom_10919_5com_10919_25799com_10919_23829com_10919_5553com_10919_23747com_10919_5539col_10919_70873col_10919_23830col_10919_23748
Interference of manganese removal by biologically-mediated reductive release of manganese from MnO<sub>x(s)</sub> coated filtration media
Swain, Lindsay E.
Knocke, William R.
Falkinham, Joseph O. III
Pruden, Amy
Drinking water treatment
Manganese oxides
Manganese removal
Manganese-reducing bacteria
Media filtration
Discontinuing application of pre-filter chlorine is a common water treatment plant practice to permit a bioactive filtration process for the removal of soluble Mn. However, soluble Mn desorption has sometimes been observed following cessation of chlorine addition, where filter effluent Mn concentration exceeds the influent Mn concentration. In this paper it is hypothesized that Mn-reducing bacteria present in a biofilm on the filter media may be a factor in this Mn-release phenomenon. The primary objective of this research was to assess the role of Mn-reducing microorganisms in the release of soluble Mn from MnOx(s)-coated filter media following interruption of pre-filtration chlorination. Bench-scale filter column studies were inoculated with Shewanella oneidensis MR-1 to investigate the impacts of a known Mn-reducing bacterium on release of soluble Mn from MnOx(s) coatings. In situ vial assays were developed to gain insight into the impacts of MnOx(s) age on bioavailability to Mn-reducing microorganisms and a quantitative polymerase chain reaction (qPCR) method was developed to quantify gene copies of the mtrB gene, which is involved in Mn-reduction. Results demonstrated that microbially-mediated Mn release was possible above a threshold equivalent of 2 × 102 S. oneidensis MR-1 CFU per gram of MnOx(s) coated media and that those organisms contributed to Mn desorption and release. Further, detectable mtrB gene copies were associated with observed Mn desorption. Lastly, MnOx(s) age appeared to play a role in Mn reduction and subsequent release, where MnOx(s) solids of greater age indicated lower bioavailability. These findings can help inform means of preventing soluble Mn release from drinking water treatment plant filters.
2021-10-19T12:20:45Z
2021-10-19T12:20:45Z
2018-12-01
2021-10-19T12:20:42Z
Article - Refereed
2589-9147
PMC6549940
100009 (PII)
http://hdl.handle.net/10919/105413
https://doi.org/10.1016/j.wroa.2018.100009
1
31194072
2589-9147
en
https://www.ncbi.nlm.nih.gov/pubmed/31194072
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Elsevier
oai:vtechworks.lib.vt.edu:10919/1093142022-03-12T08:09:01Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78882col_10919_23748
Pictures Matter: How Images of Projected Sea-Level Rise Shape Long-Term Sustainable Design Decisions for Infrastructure Systems
Milovanovic, Julie
Shealy, Tripp
Klotz, Leidy
Johnson, Eric J.
Weber, Elke U.
Community input matters in long-term decisions related to climate change, including the development of public infrastructure. In order to assess the effect of different ways of informing the public about infrastructure projects, a sample of people in the United States (<i>n</i> = 630) was provided with a case study concerning the redevelopment of the San Diego Airport. Participants received the same written information about the projected future condition of the airport. In addition, participants received images either portraying current conditions or portraying conditions in 2100 based on NOAA (National Oceanic and Atmospheric Administration) sea-level rise data. Participants were asked to choose 7 out of 21 design options to implement in the redevelopment project. The framework used for the design options stemmed from the Envision rating system. We analyzed the participants’ selection of the credits using generalized linear mixed models. Those that received the images portraying the future were significantly more likely to select design options that would reduce the risk of climate change and flooding. Images portraying sea-level rise had different effects depending on participant demographics. Such images increased the selection of design elements related to the climate and risk for participants identifying as female or as Democrat. For participants identifying as male or as Republican, the same images increased their selection of design elements to enhance community public space. The results demonstrate the positive effects of portraying the future in terms of encouraging focus on long-term sustainable design decisions for infrastructure systems.
2022-03-11T13:34:26Z
2022-03-11T13:34:26Z
2022-03-04
2022-03-10T14:18:30Z
Article - Refereed
Milovanovic, J.; Shealy, T.; Klotz, L.; Johnson, E.J.; Weber, E.U. Pictures Matter: How Images of Projected Sea-Level Rise Shape Long-Term Sustainable Design Decisions for Infrastructure Systems. Sustainability 2022, 14, 3007.
http://hdl.handle.net/10919/109314
https://doi.org/10.3390/su14053007
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/749372023-06-23T15:22:55Zcom_10919_5com_10919_25799com_10919_78629com_10919_78628com_10919_8195com_10919_23747com_10919_5539col_10919_70873col_10919_78630col_10919_18629col_10919_23748
Sources of airborne microorganisms in the built environment
Prussin, Aaron J. II
Marr, Linsey C.
Civil and Environmental Engineering
Microbiology
Microbiome
Microbes
Indoors
Bioaerosols
Emissions
Review
INDOOR-OUTDOOR RELATIONSHIPS
HOUSE-DUST
PARTICLE NUMBER
HOME DAMPNESS
MICROBIOLOGICAL HAZARDS
BACTERIAL COMMUNITIES
PULMONARY HEMORRHAGE
SIZE DISTRIBUTIONS
PARTICULATE MATTER
STACHYBOTRYS-ATRA
Each day people are exposed to millions of bioaerosols, including whole microorganisms, which can have both beneficial and detrimental effects. The next chapter in understanding the airborne microbiome of the built environment is characterizing the various sources of airborne microorganisms and the relative contribution of each. We have identified the following eight major categories of sources of airborne bacteria, viruses, and fungi in the built environment: humans; pets; plants; plumbing systems; heating, ventilation, and air-conditioning systems; mold; dust resuspension; and the outdoor environment. Certain species are associated with certain sources, but the full potential of source characterization and source apportionment has not yet been realized. Ideally, future studies will quantify detailed emission rates of microorganisms from each source and will identify the relative contribution of each source to the indoor air microbiome. This information could then be used to probe fundamental relationships between specific sources and human health, to design interventions to improve building health and human health, or even to provide evidence for forensic investigations.
2017-02-05T01:56:00Z
2017-02-05T01:56:00Z
2015-12-22
Article - Refereed
2049-2618
http://hdl.handle.net/10919/74937
https://doi.org/10.1186/s40168-015-0144-z
3
1
en
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000367061200001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=930d57c9ac61a043676db62af60056c1
http://creativecommons.org/licenses/by/4.0/
The Author(s)
Creative Commons Attribution 4.0 International
Biomed Central
oai:vtechworks.lib.vt.edu:10919/1067292023-06-23T15:22:50Zcom_10919_23747com_10919_5539col_10919_23748
Combined portable free fall penetrometer and chirp sonar measurements of three Texas river sections post hurricane Harvey
Jaber, Reem
Stark, Nina
Jafari, Navid
Ravichandran, Nadarajah
Portable free fall penetrometer
Chirp sonar
Site characterization
Fluvial sediment dynamics
Sediment strength
The US Gulf of Mexico coastal region has repeatedly been subjected to major flood events. Local geotechnical site characteristics and geomorphology can change due to sediment transport processes during such events. However, field measurements during extreme conditions are challenging. This paper discusses initial attempts at a combined geotechnical and geophysical site investigation of the uppermost layers of riverbeds following severe flooding events at three different rivers in Texas: the Guadalupe, Brazos, and Colorado Rivers in terms of sediment strength derived from a portable free fall penetrometer, backscatter intensity recorded by a chirp sonar, and soil sample characterization. Results show low strength sediments (<40 kPa) along the investigated sections of the Guadalupe and Brazos riverbanks. Although sediments in the center of the Brazos River were characterized with higher strength (>50 kPa) and larger grain sizes (d(50) similar to 0.3 mm), sediment strength of the Guadalupe and Colorado Rivers displayed more variations around bridge piers. The spatial variations likely resulted from sediment remobilization processes and local scour under severe hydrodynamic conditions. Both, geotechnical and geophysical results, reflected the observed variations in the riverbed sediments; nonetheless, a quantitative correlation among the rivers was impeded by challenges primarily related to limitations of spatial accuracy and the significant riverbed heterogeneity, as well as shallow water limitations of the chirp sonar.
2021-11-24T14:12:21Z
2021-11-24T14:12:21Z
2021-12-05
Article - Refereed
0013-7952
106324
http://hdl.handle.net/10919/106729
https://doi.org/10.1016/j.enggeo.2021.106324
294
1872-6917
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
Texas
United States
oai:vtechworks.lib.vt.edu:10919/1018072023-11-29T16:17:34Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539com_10919_5524col_10919_78882col_10919_23748col_10919_89575
Adaptive Traffic Signal Control: Game-Theoretic Decentralized vs. Centralized Perimeter Control
Elouni, Maha
Abdelghaffar, Hossam M.
Rakha, Hesham A.
Virginia Tech Transportation Institute
Civil and Environmental Engineering
perimeter control
NFD
adaptive control
game theory
DNB
This paper compares the operation of a decentralized Nash bargaining traffic signal controller (DNB) to the operation of state-of-the-art adaptive and gating traffic signal control. Perimeter control (gating), based on the network fundamental diagram (NFD), was applied on the borders of a protected urban network (PN) to prevent and/or disperse traffic congestion. The operation of gating control and local adaptive controllers was compared to the operation of the developed DNB traffic signal controller. The controllers were implemented and their performance assessed on a grid network in the INTEGRATION microscopic simulation software. The results show that the DNB controller, although not designed to solve perimeter control problems, successfully prevents congestion from building inside the PN and improves the performance of the entire network. Specifically, the DNB controller outperforms both gating and non-gating controllers, with reductions in the average travel time ranging between <inline-formula><math display="inline"><semantics><mrow><mn>21</mn><mo>%</mo></mrow></semantics></math></inline-formula> and <inline-formula><math display="inline"><semantics><mrow><mn>41</mn><mo>%</mo></mrow></semantics></math></inline-formula>, total delay ranging between <inline-formula><math display="inline"><semantics><mrow><mn>40</mn><mo>%</mo></mrow></semantics></math></inline-formula> and <inline-formula><math display="inline"><semantics><mrow><mn>55</mn><mo>%</mo></mrow></semantics></math></inline-formula>, and emission levels/fuel consumption ranging between <inline-formula><math display="inline"><semantics><mrow><mn>12</mn><mo>%</mo></mrow></semantics></math></inline-formula> and <inline-formula><math display="inline"><semantics><mrow><mn>20</mn><mo>%</mo></mrow></semantics></math></inline-formula>. The results demonstrate statistically significant benefits of using the developed DNB controller over other state-of-the-art centralized and decentralized gating/adaptive traffic signal controllers.
2021-01-08T15:51:30Z
2021-01-08T15:51:30Z
2021-01-03
2021-01-08T14:48:33Z
Article - Refereed
Elouni, M.; Abdelghaffar, H.M.; Rakha, H.A. Adaptive Traffic Signal Control: Game-Theoretic Decentralized vs. Centralized Perimeter Control. Sensors 2021, 21, 274.
http://hdl.handle.net/10919/101807
https://doi.org/10.3390/s21010274
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/1126572023-03-06T15:16:15Zcom_10919_23747com_10919_5539col_10919_23748
Antimicrobial Resistance Monitoring of Water Environments: A Framework for Standardized Methods and Quality Control
Liguori, Krista
Keenum, Ishi M.
Davis, Benjamin C.
Calarco, Jeanette
Milligan, Erin
Harwood, Valerie J.
Pruden, Amy
antibiotic resistance
surveillance
standardization
wastewater
recycled water
surface water
Antimicrobial resistance (AMR) is a grand societal challenge with important dimensions in the water environment that contribute to its evolution and spread. Environmental monitoring could provide vital information for mitigating the spread of AMR; this includes assessing antibiotic resistance genes (ARGs) circulating among human populations, identifying key hotspots for evolution and dissemination of resistance, informing epidemiological and human health risk assessment models, and quantifying removal efficiencies by domestic wastewater infrastructure. However, standardized methods for monitoring AMR in the water environment will be vital to producing the comparable data sets needed to address such questions. Here we sought to establish scientific consensus on a framework for such standardization, evaluating the state of the science and practice of AMR monitoring of wastewater, recycled water, and surface water, through a literature review, survey, and workshop leveraging the expertise of academic, governmental, consulting, and water utility professionals.
2022-11-17T13:55:15Z
2022-11-17T13:55:15Z
2022-06
Article - Refereed
0013-936X
http://hdl.handle.net/10919/112657
https://doi.org/10.1021/acs.est.1c08918
35732277
1520-5851
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
American Chemical Society
oai:vtechworks.lib.vt.edu:10919/1081362022-02-07T14:22:08Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539col_10919_70873col_10919_23748
Assessing the Impact of Land Cover, Soil, and Climate on the Storage Potential of Dryland Sand Dams
Eisma, Jessica A.
Saksena, Siddharth
Merwade, Venkatesh
Sand dams, a water-harvesting structure employed by rural communities in drylands have an inconsistent record of effectiveness. While many sand dams are highly functioning, improper siting, siltation, seepage, and high rates of evaporation from shallow sand reservoirs inhibit the water storage capacity of some sand dams. This study examines large-scale drivers of sand dam storage potential through analysis of an integrated surface and subsurface flow model. Multiple simulations were run, and comparative simulation analyses consider the effect of geomorphological factors, intraseasonal rainfall variability, and future climate conditions on sand dam performance criteria. The analyses revealed that a watershed highly cultivated with low water crops actually reduces evapotranspiration below that of natural vegetation and supports higher groundwater recharge. Additionally, intraseasonal variation and volume of rainfall impact sand dam performance less than the prevailing pattern and duration of dry and rainy seasons. Sand dams constructed in watersheds with sandier soils may experience greater connectivity with the stream margins and thus provide additional groundwater recharge. Lastly, climate change may improve some conditions desirable for sand dam performance, such as extending the duration of the rainy season and reducing overall evapotranspiration. However, the interactions between the expected climate change conditions and other geomorphological factors may result in a net decline in sand dam performance. The results of this study may help identify watersheds that are likely to support a sand dam with high potential for capturing and storing water throughout the dry season.
2022-02-04T19:08:54Z
2022-02-04T19:08:54Z
2021-07-02
2022-02-04T19:08:51Z
Article - Refereed
2624-9375
http://hdl.handle.net/10919/108136
https://doi.org/10.3389/frwa.2021.671455
3
Saksena, Siddharth [0000-0003-3746-6368]
2624-9375
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Frontiers
oai:vtechworks.lib.vt.edu:10919/1141722023-03-25T07:12:19Zcom_10919_23747com_10919_5539col_10919_23748
A frequency-velocity CNN for developing near-surface 2D vs images from linear-array, active-source wavefield measurements
Abbas, Aser
Vantassel, Joseph P.
Cox, Brady R.
Kumar, Krishna
Crocker, Jodie
Machine learning
CNN
Subsurface imaging
Surface waves
Insitu testing
Geophysical testing
This paper presents a frequency-velocity convolutional neural network (CNN) for rapid, non-invasive 2D shear wave velocity (VS) imaging of near-surface geo-materials. Operating in the frequency-velocity domain allows for significant flexibility in the linear-array, active-source experimental testing configurations used for generating the CNN input, which are normalized dispersion images. While normalized dispersion images retain the most important aspects of near-surface wavefields, they are relatively insensitive to the exact experimental testing configuration used to generate and record the wavefields, accommodating various source types, source offsets, numbers of receivers, and receiver spacings. We demonstrate the effectiveness of the frequency-velocity CNN by applying it to a common near-surface geophysics problem, namely, imaging a two-layer, undulating, soil-over -bedrock interface. The frequency-velocity CNN was trained and tested using 100,000 synthetic near-surface models with variable soil-over-bedrock conditions. Then, the ability of the frequency-velocity CNN to gener-alize across various acquisition configurations was rigorously tested using thousands of synthetic near-surface models with different acquisition configurations from that of the training set. Lastly, it was applied to experi-mental field data collected at the Hornsby Bend site in Austin, Texas, USA and found to produce a subsurface 2D image that was in great agreement with ground truth from invasive site characterization data.
2023-03-24T18:52:12Z
2023-03-24T18:52:12Z
2023-04
Article - Refereed
105305
http://hdl.handle.net/10919/114172
https://doi.org/10.1016/j.compgeo.2023.105305
156
1873-7633
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Elsevier
oai:vtechworks.lib.vt.edu:10919/1180612024-03-18T13:21:24Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539com_10919_24209com_10919_5553col_10919_70873col_10919_23748col_10919_24267
Morphodynamic and modeling insights from global sensitivity analysis of a barrier island evolution model
Hoagland, Steven
Irish, Jennifer L.
Weiss, Robert
Recently developed models of coastal barrier morphodynamics include marsh and lagoon processes that have been shown to impact barrier island evolution. To gain additional insights into the simulated barrier-backbarrier system dynamics, this study explores the parameter space of a barrier evolution model using global sensitivity analysis. Influential parameters, their interactions with one another, and regions of sensitivity within the parameter space were identified using Sobol indices and factor mapping techniques for model results through the end of the century. The results of this study highlight an important relationship between initial and critical barrier island geometries and suggest that narrow and low-relief barriers are most vulnerable to be eroded away (width drowning) or overtaken by sea level rise (height drowning), respectively. Width drowning was also strongly associated with other model input parameters such as toe depth, sea level rise rate, and backbarrier critical bed shear stress, which suggests that sub-centennial drowning is dependent on a unique combination of input parameter values and may be averted (or delayed) with a single input parameter change. Barrier dynamics were significantly influenced by the backbarrier marsh platform, which was more impacted by sediment transport parameters such as critical bed shear stress and ocean sediment concentration than maximum annual overwash flux. This suggests that inorganic sediment deposition through tidal inlet dispersion is much more significant to the backbarrier marsh and lagoon system than overwash over sub-centennial timescales and can help to reduce the risk of width drowning.
2024-02-20T14:21:43Z
2024-02-20T14:21:43Z
2024-02
Article - Refereed
0169-555X
https://hdl.handle.net/10919/118061
https://doi.org/10.1016/j.geomorph.2024.109087
Irish, Jennifer [0000-0002-2429-5953]
Hoagland, Steven [0000-0002-1133-0799]
Weiss, Robert [0000-0002-7168-5401]
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Elsevier
oai:vtechworks.lib.vt.edu:10919/1010672021-10-08T16:43:33Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78882col_10919_23748
Multiscale Analytical Method and Its Parametric Study for Lining Joint Leakage of Shield Tunnel
Wang, Yajian
Yang, Yuyou
Su, Fei
Wang, Linbing
Civil & Environmental Engineering
shield tunnel
leakage model
critical leakage pressure
EPDM gasket
service time
Understanding the underlying processes of lining joint leakage is essential for predicting its waterproofing performance, improving the design, and assessing its operational health in shield tunnels. There is little literature reported on a leakage model that can reflect various influencing factors. This article introduced an analytical method for predicting joint leakage based on recently developed multi-scale contact mechanics: the Persson model. In addition, the critical leakage state and the self-sealing effect were defined, and an approach to calculate the critical leakage pressure, as well as self-sealing stress, were deduced. Then, taking the second Dapu Road Tunnel in Shanghai as a case study, the influence of various factors, including the gap and offset of joints, the roughness of sealing materials, the service time, and groundwater pressure on the lining joint leakage, was calculated. The applicability of the model was verified by comparing the calculated results with the experimental data and monitoring data in the literature. This research could contribute to understanding the development process of seepage in sealing engineering and provide a reference for waterproof design and the performance assessment of shield tunnels’ lining joints.
2020-12-10T19:43:23Z
2020-12-10T19:43:23Z
2020-11-28
2020-12-10T14:11:11Z
Article - Refereed
Wang, Y.; Yang, Y.; Su, F.; Wang, L. Multiscale Analytical Method and Its Parametric Study for Lining Joint Leakage of Shield Tunnel. Appl. Sci. 2020, 10, 8528.
http://hdl.handle.net/10919/101067
https://doi.org/10.3390/app10238528
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/1145262023-04-18T07:12:02Zcom_10919_23747com_10919_5539col_10919_23748
Quantification of class 1 integrons and characterization of the associated gene cassettes in the high Arctic - Interplay of humans and glaciers in shaping the aquatic resistome
Makowska-Zawierucha, Nicoletta
Mokracka, Joanna
Malecka, Marcelina
Balazy, Piotr
Chelchowski, Maciej
Ignatiuk, Dariusz
Zawierucha, Krzysztof
Integrons
Antibiotic-resistant bacteria
Metagenome
Wastewater
Cryosphere
Anthropocene
The Arctic is one of the regions most affected by global climate change, and is subjected to changes linked with a melting cryosphere and increasing anthropopressure. Although antibiotic resistance is a global problem, the diversity and spread of antibiotic-resistant bacteria (ARB), antibiotic resistance genes (ARGs) and integrons in the Arctic are strongly understudied. Therefore, the main aims of this study are the (1) determination of the type and frequency of integron-integrase genes and characterization of incorporated gene cassettes in the genomes of culturable bacteria and (2) quantitative analysis of class 1 integron-integrase gene and human mitochondrial DNA (Hmt-DNA) in the metagenome as markers of anthropogenic impact on the high Arctic environments of the Svalbard Archipelago. Samples of ice, water and sediments were collected in the most populated area of Svalbard, Longyearbyen and its vicinity. Sampling was conducted along an environmental gradient with varying levels of human activity. The environmental gradient started from glaciers, following the proglacial river, the seashore, and the fjord bottom water, including untreated wastewater outflow to the sea. Class 1 integrons were detected in ARB isolated from glacial environments, freshwater and seawater, including wastewater outflow. Moreover, in the variable regions of integrons, genes determining different functions, including antibiotic resistance, virulence and physiological traits were found. These genes play crucial roles in the adaptation of bacteria to cold and dynamic environments. The relative abundance of intI1 genes were reported in metagenomes with different relationships to human activity (ice cores vs wastewater outflow), with the highest mean values observed in the wastewater outflow, and was positively correlated with abundance of the Hmt gene, revealing both natural and human roles in shaping the polar aquatic resistome.
2023-04-17T15:05:49Z
2023-04-17T15:05:49Z
2022-12
Article - Refereed
http://hdl.handle.net/10919/114526
https://doi.org/10.1016/j.ecolind.2022.109633
145
1872-7034
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Elsevier
oai:vtechworks.lib.vt.edu:10919/854092023-04-14T17:49:39Zcom_10919_23747com_10919_5539col_10919_23748
Convenient, Rapid and Accurate Measurement of SVOC Emission Characteristics in Experimental Chambers
Liu, Cong
Liu, Zhe
Little, John C.
Zhang, Yinping
Civil and Environmental Engineering
Chamber tests are usually used to determine the source characteristics of semi-volatile organic compounds (SVOCs) which are critical to quantify indoor exposure to SVOCs. In contrast to volatile organic compounds (VOCs), the sorption effect of SVOCs to chamber surfaces usually needs to be considered due to the much higher surface/air partition coefficients, resulting in a long time to reach steady state, frequently on the order of months, and complicating the mathematical analysis of the resulting data. A chamber test is also complicated if the material-phase concentration is not constant. This study shows how to design a chamber to overcome these limitations. A dimensionless mass transfer analysis is used to specify conditions for (1) neglecting the SVOC sorption effect to chamber surfaces, (2) neglecting the convective mass transfer resistance at sorption surfaces if the sorption effect cannot be neglected, and (3) regarding the material-phase concentration in the source as constant. Several practical and quantifiable ways to improve chamber design are proposed. The approach is illustrated by analyzing available data from three different chambers in terms of the accuracy with which the model parameters can be determined and the time needed to conduct the chamber test. The results should greatly facilitate the design of chambers to characterize SVOC emissions and the resulting exposure.
2018-10-18T16:58:14Z
2018-10-18T16:58:14Z
2013-08-28
Article - Refereed
e72445
http://hdl.handle.net/10919/85409
https://doi.org/10.1371/journal.pone.0072445
8
8
24015246
1932-6203
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
PLOS
oai:vtechworks.lib.vt.edu:10919/1108132023-11-29T19:08:35Zcom_10919_5540com_10919_23747com_10919_5539com_10919_19035col_10919_71752col_10919_23748col_10919_24290
Two-Stage Clustering of Household Electricity Load Shapes for Improved Temporal Pattern Representation
Afzalan, Milad
Jazizadeh, Farrokh
Eldardiry, Hoda
Clustering methods
energy segmentation
demand response
smart meters
energy management
two-stage clustering
With the widespread adoption of smart meters in buildings, an unprecedented amount of high-resolution energy data is released, which provides opportunities to understand building consumption patterns. Accordingly, research efforts have employed data analytics and machine learning methods to segment customers based on their load profiles, which help utilities and energy providers promote customized/ personalized targeting for energy programs. Existing energy consumption segmentation techniques use assumptions that could reduce clusters' quality in representing their members. Therefore, in this paper, we investigated a two-stage clustering method for capturing more representative load shape temporal patterns and peak demands through a cluster merging approach. In the first stage, load shapes are clustered (using classical clustering algorithms) by allowing a large number of clusters to accurately capture variations in energy use patterns, and cluster centroids are extracted by accounting for limited shape misalignment within the range of Demand Response (DR) timeframes. In the second stage, clusters with similar centroids and power magnitude ranges are merged using Complexity-Invariant Dynamic Time Warping. We used three datasets consisting of ~250 households (~15000 profiles) to demonstrate the efficacy of the framework, compared to baseline methods, and discuss the impact on energy management. The proposed investigated merging-based clustering also increased correlation between cluster centroids and the corresponding members by 3-9% for different datasets.
2022-06-16T20:44:45Z
2022-06-16T20:44:45Z
2021-11-16
Article - Refereed
http://hdl.handle.net/10919/110813
https://doi.org/10.1109/access.2021.3122082
9
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
IEEE
oai:vtechworks.lib.vt.edu:10919/1144462023-04-08T07:12:53Zcom_10919_23747com_10919_5539col_10919_23748
NSF Fellows’ perceptions about incentives, research misconduct, and scientific integrity in STEM academia
Roy, Siddhartha
Edwards, Marc A.
Academic integrity
Academic incentives
Research misconduct
Survey
National Science Foundation Fellows
There is increased concern about perverse incentives, quantitative performance metrics, and hyper-competition for funding and faculty positions in US academia. Recipients of the prestigious National Science Foundation Graduate Research Fellowships (n = 244) from Civil and Environmental Engineering (45.5%) and Computer Science and Engineering (54.5%) were anonymously surveyed to create a baseline snapshot of their perceptions, behaviors and experiences. NSF Fellows ranked scientific advancement as the top metric for evaluating academics followed by publishing in high-impact journals, social impact of research, and publication/citation counts. The self-reported rate of academic cheating was 16.7% and of research misconduct was 3.7%. Thirty-one percent of fellows reported direct knowledge of graduate peers cheating, and 11.9% had knowledge of research misconduct by colleagues. Only 30.7% said they would report suspected misconduct. A majority of fellows (55.3%) felt that mandatory ethics trainings left them unprepared for dealing with ethical issues. Fellows stated academic freedom, flexible schedules and opportunity to mentor students were the most positive aspects of academia, whereas pressures for funding, publication, and tenure were cited as the most negative aspects. These data may be useful in considering how to better prepare STEM graduate trainees for academic careers.
2023-04-07T17:49:49Z
2023-04-07T17:49:49Z
2023-04-07
Article - Refereed
Roy, S., Edwards, M.A. NSF Fellows’ perceptions about incentives, research misconduct, and scientific integrity in STEM academia. Sci Rep 13, 5701 (2023). https://doi.org/10.1038/s41598-023-32445-3
http://hdl.handle.net/10919/114446
https://doi.org/10.1038/s41598-023-32445-3
13
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Springer Nature
oai:vtechworks.lib.vt.edu:10919/895542022-03-29T18:27:49Zcom_10919_78629com_10919_78628com_10919_8195com_10919_25799com_10919_11363com_10919_5539com_10919_24216com_10919_23747com_10919_91436com_10919_5532col_10919_79980col_10919_78882col_10919_23164col_10919_24286col_10919_23748col_10919_97229
Intercomparison of Small Unmanned Aircraft System (sUAS) Measurements for Atmospheric Science during the LAPSE-RATE Campaign
Barbieri, Lindsay
Kral, Stephan T.
Bailey, Sean C. C.
Frazier, Amy E.
Jacob, Jamey D.
Reuder, Joachim
Brus, David
Chilson, Phillip B.
Crick, Christopher
Detweiler, Carrick
Doddi, Abhiram
Elston, Jack
Foroutan, Hosein
González-Rocha, Javier
Greene, Brian R.
Guzman, Marcelo I.
Houston, Adam L.
Islam, Ashraful
Kemppinen, Osku
Lawrence, Dale
Pillar-Little, Elizabeth A.
Ross, Shane D.
Sama, Michael P.
Schmale, David G. III
Schuyler, Travis J.
Shankar, Ajay
Smith, Suzanne W.
Waugh, Sean
Dixon, Cory
Borenstein, Steve
de Boer, Gijs
Civil and Environmental Engineering
Aerospace and Ocean Engineering
Biomedical Engineering and Mechanics
School of Plant and Environmental Sciences
sUAS
unmanned aircraft systems
unmanned aerial vehicles
Drone aircraft
sensor intercomparison
atmospheric measurements
Small unmanned aircraft systems (sUAS) are rapidly transforming atmospheric research. With the advancement of the development and application of these systems, improving knowledge of best practices for accurate measurement is critical for achieving scientific goals. We present results from an intercomparison of atmospheric measurement data from the Lower Atmospheric Process Studies at Elevation—a Remotely piloted Aircraft Team Experiment (LAPSE-RATE) field campaign. We evaluate a total of 38 individual sUAS with 23 unique sensor and platform configurations using a meteorological tower for reference measurements. We assess precision, bias, and time response of sUAS measurements of temperature, humidity, pressure, wind speed, and wind direction. Most sUAS measurements show broad agreement with the reference, particularly temperature and wind speed, with mean value differences of 1.6 <inline-formula> <math display="inline"> <semantics> <mrow> <mo>±</mo> <mn>2.6</mn> <msup> <mspace width="3.33333pt"></mspace> <mo>∘</mo> </msup> </mrow> </semantics> </math> </inline-formula>C and 0.22 <inline-formula> <math display="inline"> <semantics> <mrow> <mo>±</mo> <mspace width="3.33333pt"></mspace> <mn>0.59</mn> </mrow> </semantics> </math> </inline-formula> m/s for all sUAS, respectively. sUAS platform and sensor configurations were found to contribute significantly to measurement accuracy. Sensor configurations, which included proper aspiration and radiation shielding of sensors, were found to provide the most accurate thermodynamic measurements (temperature and relative humidity), whereas sonic anemometers on multirotor platforms provided the most accurate wind measurements (horizontal speed and direction). We contribute both a characterization and assessment of sUAS for measuring atmospheric parameters, and identify important challenges and opportunities for improving scientific measurements with sUAS.
2019-05-17T14:43:55Z
2019-05-17T14:43:55Z
2019-05-10
2019-05-16T20:03:44Z
Article - Refereed
Barbieri, L.; Kral, S.T.; Bailey, S.C.C.; Frazier, A.E.; Jacob, J.D.; Reuder, J.; Brus, D.; Chilson, P.B.; Crick, C.; Detweiler, C.; Doddi, A.; Elston, J.; Foroutan, H.; González-Rocha, J.; Greene, B.R.; Guzman, M.I.; Houston, A.L.; Islam, A.; Kemppinen, O.; Lawrence, D.; Pillar-Little, E.A.; Ross, S.D.; Sama, M.P.; Schmale, D.G.; Schuyler, T.J.; Shankar, A.; Smith, S.W.; Waugh, S.; Dixon, C.; Borenstein, S.; de Boer, G. Intercomparison of Small Unmanned Aircraft System (sUAS) Measurements for Atmospheric Science during the LAPSE-RATE Campaign. Sensors 2019, 19, 2179.
http://hdl.handle.net/10919/89554
https://doi.org/10.3390/s19092179
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/1047032022-06-16T17:38:38Zcom_10919_5com_10919_25799com_10919_78629com_10919_78628com_10919_23747com_10919_5539col_10919_70873col_10919_78630col_10919_23748
Evaluation of Metagenomic-Enabled Antibiotic Resistance Surveillance at a Conventional Wastewater Treatment Plant
Majeed, Haniyyah J.
Riquelme, Maria V.
Davis, Benjamin C.
Gupta, Suraj
Angeles, Luisa F.
Aga, Diana S.
Garner, Emily
Pruden, Amy
Vikesland, Peter J.
Civil and Environmental Engineering
Life Sciences & Biomedicine
Microbiology
shotgun sequencing
resistome
microbiome
antibiotics
antibiograms
resistome (ARGs and MGEs)
ESCHERICHIA-COLI
GENES
PREVALENCE
BACTERIA
HOTSPOTS
SEWAGE
0502 Environmental Science and Management
0503 Soil Sciences
0605 Microbiology
Wastewater treatment plants (WWTPs) receive a confluence of sewage containing antimicrobials, antibiotic resistant bacteria, antibiotic resistance genes (ARGs), and pathogens and thus are a key point of interest for antibiotic resistance surveillance. WWTP monitoring has the potential to inform with respect to the antibiotic resistance status of the community served as well as the potential for ARGs to escape treatment. However, there is lack of agreement regarding suitable sampling frequencies and monitoring targets to facilitate comparison within and among individual WWTPs. The objective of this study was to comprehensively evaluate patterns in metagenomic-derived indicators of antibiotic resistance through various stages of treatment at a conventional WWTP for the purpose of informing local monitoring approaches that are also informative for global comparison. Relative abundance of total ARGs decreased by ∼50% from the influent to the effluent, with each sampling location defined by a unique resistome (i.e., total ARG) composition. However, 90% of the ARGs found in the effluent were also detected in the influent, while the effluent ARG-pathogen taxonomic linkage patterns identified in assembled metagenomes were more similar to patterns in regional clinical surveillance data than the patterns identified in the influent. Analysis of core and discriminatory resistomes and general ARG trends across the eight sampling events (i.e., tendency to be removed, increase, decrease, or be found in the effluent only), along with quantification of ARGs of clinical concern, aided in identifying candidate ARGs for surveillance. Relative resistome risk characterization further provided a comprehensive metric for predicting the relative mobility of ARGs and likelihood of being carried in pathogens and can help to prioritize where to focus future monitoring and mitigation. Most antibiotics that were subject to regional resistance testing were also found in the WWTP, with the total antibiotic load decreasing by ∼40–50%, but no strong correlations were found between antibiotics and corresponding ARGs. Overall, this study provides insight into how metagenomic data can be collected and analyzed for surveillance of antibiotic resistance at WWTPs, suggesting that effluent is a beneficial monitoring point with relevance both to the local clinical condition and for assessing efficacy of wastewater treatment in reducing risk of disseminating antibiotic resistance.
2021-08-25T12:02:24Z
2021-08-25T12:02:24Z
2021-05-13
2021-08-25T12:02:20Z
Article - Refereed
1664-302X
http://hdl.handle.net/10919/104703
https://doi.org/10.3389/fmicb.2021.657954
12
Vikesland, Peter [0000-0003-2654-5132]
34054755
1664-302X
en
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000655038000001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=930d57c9ac61a043676db62af60056c1
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Frontiers
oai:vtechworks.lib.vt.edu:10919/1172062023-12-16T03:01:51Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539com_10919_19035com_10919_111086com_10919_5532com_10919_91436col_10919_70873col_10919_23748col_10919_24290col_10919_111087col_10919_97229
ARGem: a new metagenomics pipeline for antibiotic resistance genes: metadata, analysis, and visualization
Liang, Xiao
Zhang, Jingyi
Kim, Yoonjin
Ho, Josh
Liu, Kevin
Keenum, Ishi M.
Gupta, Suraj
Davis, Benjamin
Hepp, Shannon L.
Zhang, Liqing
Xia, Kang
Knowlton, Katharine F.
Liao, Jingqiu
Vikesland, Peter J.
Pruden, Amy
Heath, Lenwood S.
antibiotic resistance genes
workflow
metagenomics
bioinformatics
genome annotation
Antibiotic resistance is of crucial interest to both human and animal medicine. It has been recognized that increased environmental monitoring of antibiotic resistance is needed. Metagenomic DNA sequencing is becoming an attractive method to profile antibiotic resistance genes (ARGs), including a special focus on pathogens. A number of computational pipelines are available and under development to support environmental ARG monitoring; the pipeline we present here is promising for general adoption for the purpose of harmonized global monitoring. Specifically, ARGem is a user-friendly pipeline that provides full-service analysis, from the initial DNA short reads to the final visualization of results. The capture of extensive metadata is also facilitated to support comparability across projects and broader monitoring goals. The ARGem pipeline offers efficient analysis of a modest number of samples along with affordable computational components, though the throughput could be increased through cloud resources, based on the user’s configuration. The pipeline components were carefully assessed and selected to satisfy tradeoffs, balancing efficiency and flexibility. It was essential to provide a step to perform short read assembly in a reasonable time frame to ensure accurate annotation of identified ARGs. Comprehensive ARG and mobile genetic element databases are included in ARGem for annotation support. ARGem further includes an expandable set of analysis tools that include statistical and network analysis and supports various useful visualization techniques, including Cytoscape visualization of co-occurrence and correlation networks. The performance and flexibility of the ARGem pipeline is demonstrated with analysis of aquatic metagenomes. The pipeline is freely available at https://github.com/xlxlxlx/ARGem.
2023-12-15T17:52:11Z
2023-12-15T17:52:11Z
2023-09-15
Article - Refereed
1664-8021
PMC10558085
1219297 (PII)
https://hdl.handle.net/10919/117206
https://doi.org/10.3389/fgene.2023.1219297
14
Vikesland, Peter [0000-0003-2654-5132]
Pruden-Bagchi, Amy [0000-0002-3191-6244]
Knowlton, Katharine [0000-0002-7181-4410]
Heath, Lenwood [0000-0003-1608-431X]
Zhang, Liqing [0000-0003-4660-9199]
37811141
1664-8021
en
https://www.ncbi.nlm.nih.gov/pubmed/37811141
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Frontiers
oai:vtechworks.lib.vt.edu:10919/843852023-06-23T15:22:55Zcom_10919_23747com_10919_5539col_10919_23748
Evaluating Water Lead Levels During the Flint Water Crisis
Pieper, Kelsey J.
Martin, Rebekah L.
Tang, Min
Walters, LeeAnne
Parks, Jeffrey L.
Roy, Siddhartha
Devine, Christina
Edwards, Marc A.
Civil and Environmental Engineering
In April 2014, the drinking water source in Flint, Michigan was switched from Lake Huron water with phosphate inhibitors to Flint River water without corrosion inhibitors. The absence of corrosion control and use of a more corrosive source increased lead leaching from plumbing. Our city-wide citizen science water lead results contradicted official claims that there was no problem– our 90th percentile was 26.8 μg/L, which was almost double the Lead and Copper Rule action level of 15 μg/L. Back calculations of a LCR sampling pool with 50% lead pipes indicated an estimated 90th percentile lead value of 31.7 μg/L (±4.3 μg/L). Four subsequent sampling efforts were conducted to track reductions in water lead after the switch back to Lake Huron water and enhanced corrosion control. The incidence of water lead varied by service line material. Between August 2015 and November 2016, median water lead reduced from 3.0 to <1 μg/L for homes with copper service lines, 7.2–1.9 μg/L with galvanized service lines, and 9.9–2.3 μg/L with lead service lines. As of summer 2017, our 90th percentile of 7.9 μg/L no longer differed from official results, which indicated Flint’s water lead levels were below the action level.
2018-07-25T12:52:54Z
2018-07-25T12:52:54Z
2018-06-22
Article - Refereed
http://hdl.handle.net/10919/84385
https://doi.org/10.1021/acs.est.8b00791
en
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
ACS
oai:vtechworks.lib.vt.edu:10919/1007802023-11-29T12:27:20Zcom_10919_52249com_10919_5557com_10919_23747com_10919_5539com_10919_23965com_10919_23966com_10919_24236com_10919_5538com_10919_111116com_10919_5555com_10919_79468com_10919_78628col_10919_52250col_10919_23748col_10919_24280col_10919_24330col_10919_24310col_10919_111120col_10919_79480
Catawba Sustainability Center and Catawba Hospital Renewable Energy Site Planning Process Study
Meyers, Ron
Carstensen, Laurence W.
Ford, W. Mark
Grant, Elizabeth J.
Klopfer, Scott D.
Schenk, Todd
Taylor, Adam
The transdisciplinary Renewable Energy Facilities Siting Project produced a white paper outlining their proof-of-concept using a case study from the Catawba Valley.
2020-11-03T15:14:39Z
2020-11-03T15:14:39Z
2020-09-29
Report
http://hdl.handle.net/10919/100780
https://www.provost.vt.edu/content/dam/provost_vt_edu/da-assets/docs/policy/VT-REFS%20Catawba%20Sustainability%20Center%20and%20Catawba%20Hospital%20Renewable%20Energy%20Site%20Planning%20Study%202020.pdf
en
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
Virginia Tech
oai:vtechworks.lib.vt.edu:10919/1177942024-02-01T10:13:07Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78882col_10919_23748
Relating Geotechnical Sediment Properties and Low Frequency CHIRP Sonar Measurements
Jaber, Reem
Stark, Nina
Sarlo, Rodrigo
McNinch, Jesse E.
Massey, Grace
Low frequency acoustic methods are a common tool for seabed stratigraphy mapping. Due to the efficiency in seabed mapping compared to geotechnical methods, estimating geotechnical sediment properties from acoustic surveying is attractive for many applications. In this study, co-located geotechnical and geoacoustic measurements of different seabed sediment types in shallow water environments (<5 m of water depth) are analyzed. Acoustic impedance estimated from sediment properties based on laboratory testing of physical samples is compared to acoustic impedance deduced from CHIRP sonar measurements using an inversion approach. Portable free fall penetrometer measurements provided in situ sediment strength. The results show that acoustic impedance values deduced from acoustic data through inversion fall within a range of ±25% of acoustic impedance estimated from porosity and bulk density. The acoustic measurements reflect variations in shallow sediment properties such as porosity and bulk density (~10 cm below seabed surface), even for very soft sediments (<i>s<sub>u</sub></i> < 3 kPa) and loose sands (~20% relative density). This is a step towards validating the ability of acoustic methods to capture geotechnical properties in the topmost seabed layers.
2024-02-01T14:31:20Z
2024-02-01T14:31:20Z
2024-01-08
2024-01-26T14:10:36Z
Article - Refereed
Jaber, R.; Stark, N.; Sarlo, R.; McNinch, J.E.; Massey, G. Relating Geotechnical Sediment Properties and Low Frequency CHIRP Sonar Measurements. Remote Sens. 2024, 16, 241.
https://hdl.handle.net/10919/117794
https://doi.org/10.3390/rs16020241
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/1000802023-11-29T19:08:45Zcom_10919_8195com_10919_25799com_10919_5540com_10919_23747com_10919_5539col_10919_78882col_10919_71752col_10919_23748
Stabilization of a Clayey Soil with Ladle Metallurgy Furnace Slag Fines
Brand, Alexander S.
Singhvi, Punit
Fanijo, Ebenezer O.
Tutumluer, Erol
Civil and Environmental Engineering
steel furnace slag (SFS)
ladle metallurgy furnace (LMF) slag
soil stabilization
unconfined compressive strength
dynamic modulus
slag characterization
The research study described in this paper investigated the potential to use steel furnace slag (SFS) as a stabilizing additive for clayey soils. Even though SFS has limited applications in civil engineering infrastructure due to the formation of deleterious expansion in the presence of water, the free CaO and free MgO contents allow for the SFS to be a potentially suitable candidate for clayey soil stabilization and improvement. In this investigation, a kaolinite clay was stabilized with 10% and 15% ladle metallurgy furnace (LMF) slag fines by weight. This experimental study also included testing of the SFS mixtures with the activator calcium chloride (CaCl<sub>2</sub>), which was hypothesized to accelerate the hydration of the dicalcium silicate phase in the SFS, but the results show that the addition of CaCl<sub>2</sub> was not found to be effective. Relative to the unmodified clay, the unconfined compressive strength increased by 67% and 91% when 10% and 15% LMF slag were utilized, respectively. Likewise, the dynamic modulus increased by 212% and 221% by adding 10% and 15% LMF slag, respectively. Specifically, the LMF slag fines are posited to primarily contribute to a mechanical rather than chemical stabilization mechanism. Overall, these findings suggest the effective utilization of SFS as a soil stabilization admixture to overcome problems associated with dispersive soils, but further research is required.
2020-09-28T12:40:10Z
2020-09-28T12:40:10Z
2020-09-24
2020-09-25T13:30:50Z
Article - Refereed
Brand, A.S.; Singhvi, P.; Fanijo, E.O.; Tutumluer, E. Stabilization of a Clayey Soil with Ladle Metallurgy Furnace Slag Fines. Materials 2020, 13, 4251.
http://hdl.handle.net/10919/100080
https://doi.org/10.3390/ma13194251
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/1063632021-10-28T07:11:29Zcom_10919_23747com_10919_5539col_10919_23748
Innovative Lateral Resisting Systems with Seismic Protective Dampers and Guideline Design Procedures
Farzampour, Alireza
Mansouri, Iman
Hu, Jong Wan
Lateral Resisting System
Damper
Shear link
Eccentrically braced frame
Several conventional structures are in need of proper design and construction to resist seismic loads without experiencing a significant amount of damages. Sufficient strength and stiffness of seismic protective devices would eventually reduce the structural vulnerabilities due to the serious damage under seismic loading. There are variations of structural elements with adequate ductility and energy dissipating capability, which could be implemented as structural fuses to reduce the seismic effects, especially for high-rise buildings. For this purpose, dampers are typically used for improving the seismic energy dissipation, the concentration of the damages in a specific part of the system, proving more ductility, and reducing the unpredictable high plastic strains within the structures. In this study, the widely used conventional eccentrically braced systems are considered for further investigations, and the effects of the implementation of the seismic links in multi-story structures are analyzed for multi-story prototype structures by using verified computational models. Subsequently, innovative seismic protective dampers consist of several butterfly-shaped shear links with a linearly varying width between larger ends, and a smaller middle section is introduced. Ultimately, guideline design procedures are developed for redesigning the conventional eccentrically braced frame (EBF) systems with innovative seismic protective dampers, and backbone curves are derived and compared accordingly.
2021-10-27T13:28:56Z
2021-10-27T13:28:56Z
2022-01-01
Conference proceeding
http://hdl.handle.net/10919/106363
en
11th International Symposium on Steel Structures, November 3-6, 2021, Jeju, Korea
oai:vtechworks.lib.vt.edu:10919/648212023-11-29T19:08:46Zcom_10919_5540com_10919_23747com_10919_5539col_10919_71752col_10919_23748
Quantifying Human Mobility Perturbation and Resilience in Hurricane Sandy
Wang, Qi
Taylor, John E.
Wu, Ye
Civil and Environmental Engineering
Human movement
Hurricanes
Natural disasters
Twitter
Geographic distribution
New York
Storms
Urban areas
Human mobility is influenced by environmental change and natural disasters. Researchers have used trip distance distribution, radius of gyration of movements, and individuals' visited locations to understand and capture human mobility patterns and trajectories. However, our knowledge of human movements during natural disasters is limited owing to both a lack of empirical data and the low precision of available data. Here, we studied human mobility using high-resolution movement data from individuals in New York City during and for several days after Hurricane Sandy in 2012. We found the human movements followed truncated power-law distributions during and after Hurricane Sandy, although the β value was noticeably larger during the first 24 hours after the storm struck. Also, we examined two parameters: the center of mass and the radius of gyration of each individual's movements. We found that their values during perturbation states and steady states are highly correlated, suggesting human mobility data obtained in steady states can possibly predict the perturbation state. Our results demonstrate that human movement trajectories experienced significant perturbations during hurricanes, but also exhibited high resilience. We expect the study will stimulate future research on the perturbation and inherent resilience of human mobility under the influence of hurricanes. For example, mobility patterns in coastal urban areas could be examined as hurricanes approach, gain or dissipate in strength, and as the path of the storm changes. Understanding nuances of human mobility under the influence of such disasters will enable more effective evacuation, emergency response planning and development of strategies and policies to reduce fatality, injury, and economic loss.
2016-02-16T08:03:29Z
2016-02-16T08:03:29Z
2014-11-19
2016-02-12
Article - Refereed
Wang Q, Taylor JE (2014) Quantifying Human Mobility Perturbation and Resilience in Hurricane Sandy. PLoS ONE 9(11): e112608. doi:10.1371/journal. Pone.0112608
1932-6203
http://hdl.handle.net/10919/64821
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0112608
https://doi.org/10.1371/journal.pone.0112608
9
11
en
http://creativecommons.org/licenses/by/4.0/
Wang, Qi
Taylor, John E
Creative Commons Attribution 4.0 International
Public Library of Science
oai:vtechworks.lib.vt.edu:10919/884352023-06-23T15:22:59Zcom_10919_23747com_10919_5539col_10919_23748
Shotgun Metagenomics Reveals Taxonomic and Functional Shifts in Hot Water Microbiome Due to Temperature Setting and Stagnation
Dai, Dongjuan
Rhoads, William J.
Edwards, Marc A.
Pruden, Amy
Civil and Environmental Engineering
Hot water premise plumbing has emerged as a critical nexus of energy, water, and public health. The composition of hot water microbiomes is of special interest given daily human exposure to resident flora, especially opportunistic pathogens (OPs), which rely on complex microbial ecological interactions for their proliferation. Here, we applied shotgun metagenomic sequencing to characterize taxonomic and functional shifts in microbiomes as a function of water heater temperature setting, stagnation in distal pipes, and associated shifts in water chemistry. A cross-section of samples from controlled, replicated, pilot-scale hot water plumbing rigs representing different temperature settings (39, 42, and 51 degrees C), stagnation periods (8 h vs. 7 days), and time-points, were analyzed. Temperature setting exhibited an overarching impact on taxonomic and functional gene composition. Further, distinct taxa were selectively enriched by specific temperature settings (e.g., Legionella at 39 degrees C vs. Deinococcus at 51 degrees C), while relative abundances of genes encoding corresponding cellular functions were highly consistent with expectations based on the taxa driving these shifts. Stagnation in distal taps diminished taxonomic and functional differences induced by heating the cold influent water to hot water in recirculating line. In distal taps relative to recirculating hot water, reads annotated as being involved in metabolism and growth decreased, while annotations corresponding to stress response (e.g., virulence disease and defense, and specifically antibiotic resistance) increased. Reads corresponding to OPs were readily identified by metagenomic analysis, with L. pneumophlla reads in particular correlating remarkably well with gene copy numbers measured by quantitative polymerase chain reaction. Positive correlations between L. pneumophila reads and those of known protozoan hosts were also identified. Elevated proportions of genes encoding metal resistance and hydrogen metabolism were noted, which was consistent with elevated corrosion-induced metal concentrations and hydrogen generation. This study provided new insights into real-world factors influencing taxonomic and functional compositions of hot water microbiomes. Here metagenomics is demonstrated as an effective tool for screening for potential presence, and even quantities, of pathogens, while also providing diagnostic capabilities for assessing functional responses of microbiomes to various operational conditions. These findings can aid in informing future monitoring and intentional control of hot water microbiomes.
2019-03-13T18:34:27Z
2019-03-13T18:34:27Z
2018-11-13
Article - Refereed
1664-302X
2695
http://hdl.handle.net/10919/88435
https://doi.org/10.3389/fmicb.2018.02695
9
30542327
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Frontiers
oai:vtechworks.lib.vt.edu:10919/735292024-03-12T15:59:27Zcom_10919_5com_10919_25799com_10919_23747com_10919_5539col_10919_70873col_10919_23748
Bioelectricity inhibits back diffusion from the anolyte into the desalinated stream in microbial desalination cells
Ping, Qingyun
Porat, Oded
Dosoretz, Carlos G.
He, Zhen
Civil and Environmental Engineering
Technology
Engineering, Environmental
Environmental Sciences
Water Resources
Engineering
Environmental Sciences & Ecology
Microbial desalination cells
Back diffusion
Wastewater treatment
Donnan effect
Molecular transport
WASTE-WATER TREATMENT
ELECTRICITY-GENERATION
SEAWATER DESALINATION
PERFORMANCE
2016-11-29T16:08:46Z
2016-11-29T16:08:46Z
2016-01-01
Article - Refereed
0043-1354
http://hdl.handle.net/10919/73529
https://doi.org/10.1016/j.watres.2015.10.018
88
en
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000367276500026&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=930d57c9ac61a043676db62af60056c1
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
Pergamon-Elsevier
oai:vtechworks.lib.vt.edu:10919/1120832022-10-06T07:18:54Zcom_10919_23747com_10919_5539col_10919_23748
Kaolinite deposition from moving suspensions: The roles of flocculation, salinity, suspended sediment concentration and flow velocity/bed shear
Schieber, Juergen
Li, Zhiyang
Yawar, Zalmai
Cao, Xiaomeng
Ashley, Thomas
Wilson, Ryan
Depositional environment
evaporite
Gale Crater
geochemistry
Mars
mudstone
provenance
sequence stratigraphy
Understanding how mud moves and deposits is essential for conceptualizing the dynamic nature of surface environments and their ancient counterparts. Experimental study has largely been pursued by civil engineers, using kaolinite as an active ingredient. Yet, applying their data to the physical comprehension of mudstone sedimentology is hampered by multiple flume configurations between labs, and data sets tailored to specific engineering needs. The need for a better grasp of underlying processes is acute, given recent flume studies that show that moving suspensions form large bedload floccules, migrating floccule ripples and bed accretion under currents capable of moving sand grains. To advance mudstone sedimentology, integrated study of suspended sediment concentration, salinity and bed shear stress on the deposition of floccules is crucial. Described here is a set of tightly controlled experiments that explored suspended sediment concentrations from 70 to 900 mg/l, freshwater, brackish and marine salinities, flow velocities in the 5 to 50 cm/s range (equivalent to 0.01 to 0.58 Pa bed shear), measured the size of in-flow and bedload floccules, and the critical velocity of sedimentation that marks the onset of sustained bedload accumulation. The critical velocity of sedimentation of kaolinite clays is in the 26 to 28 cm/s flow velocity range (0.22 to 0.25 Pa), appears insensitive to a wide range of suspended sediment concentrations and salinities, and coincides with the formation of sand-size bedload floccules. Further decrease of flow velocity/bed shear stress is accompanied by a steady increase in the size of bedload floccules. Large bedload floccules appear to form in the high-shear basal part of the flow, a phenomenon requiring further investigation. Better understanding of the mechanisms that facilitate mud deposition from moving suspensions is critical for more realistic assessments of the depositional conditions of mud and mudstones, as well as for refining predictive models for the flux of fine-grained sediments across the Earth's surface.
2022-10-05T17:04:58Z
2022-10-05T17:04:58Z
2022-08
Article - Refereed
0037-0746
http://hdl.handle.net/10919/112083
https://doi.org/10.1111/sed.13034
1365-3091
en
http://creativecommons.org/licenses/by-nc/4.0/
Creative Commons Attribution-NonCommercial 4.0 International
Wiley
oai:vtechworks.lib.vt.edu:10919/730522023-11-29T19:08:52Zcom_10919_5com_10919_25799com_10919_5540com_10919_23747com_10919_5539com_10919_24231com_10919_5532col_10919_70873col_10919_71752col_10919_23748col_10919_24306
Analysis of salivary fluid and chemosensory functions in patients treated for primary malignant brain tumors
Mirlohi, Susan
Duncan, Susan E.
Harmon, M.
Case, D.
Lesser, G.
Dietrich, Andrea M.
Civil and Environmental Engineering
Food Science and Technology
Dentistry, Oral Surgery & Medicine
Metallic flavor
Oral lipid oxidation
Cancer
Brain tumor
Chemotherapy
Saliva
Taste and smell
QUALITY-OF-LIFE
METALLIC FLAVOR
CANCER-PATIENTS
NECK-CANCER
RECEIVING CHEMOTHERAPY
LIPID OXIDATION
TASTE DISORDERS
BREAST-CANCER
ZINC-SULFATE
FOOD-INTAKE
Objectives The frequency and causes of chemosensory (taste and smell) disorders in cancer patients remain under-reported. This study examined the impact of cancer therapy on taste/ smell functions and salivary constituents in brain tumor patients. Materials and methods Twenty-two newly diagnosed patients with primary malignant gliomas underwent 6 weeks of combined modality treatment (CMD) with radiation and temozolomide followed by six monthly cycles of temozolomide. Chemosensory functions were assessed at 0, 3, 6, 10, 18, and 30 weeks with paired samples of saliva collected before and after an oral rinse with ferrous-spiked water. Iron (Fe)- induced oxidative stress was measured by salivary lipid oxidation (SLO); salivary proteins, electrolytes, and metals were determined. Parallel salivary analyses were performed on 22 healthy subjects. Results Chemosensory complaints of cancer patients increased significantly during treatment (p=0.04) except at 30 weeks. Fe-induced SLO increased at 10 and 18 weeks. When compared with healthy subjects, SLO, total protein, Na, K, Cu, P, S, and Mg levels, as averaged across all times, were significantly higher (p<0.05), whereas salivary Zn, Fe, and oral pH levels were significantly lower in cancer patients (p<0.05). Neither time nor treatment had a significant impact on these salivary parameters in cancer patients. Conclusions Impact of CMT treatment on chemosensory functions can range from minimal to moderate impairment. Analysis of SLO, metals, and total protein do not provide for reliable measures of chemosensory dysfunctions over time. Clinical relevance Taste and smell functions are relevant in health and diseases; study of salivary constituents may provide clues on the causes of their dysfunctions.
2016-09-28T18:18:33Z
2016-09-28T18:18:33Z
2015-01-01
Article - Refereed
1432-6981
http://hdl.handle.net/10919/73052
https://doi.org/10.1007/s00784-014-1211-8
19
1
en
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000348981100015&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=930d57c9ac61a043676db62af60056c1
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Springer
oai:vtechworks.lib.vt.edu:10919/1063622021-10-28T07:11:28Zcom_10919_78629com_10919_78628com_10919_23747com_10919_5539col_10919_78630col_10919_23748
EMBRACE-WATERS statement: Recommendations for reporting of studies on antimicrobial resistance in wastewater and related aquatic environments
Hassoun-Kheir, Nasreen
Stabholz, Yoav
Kreft, Jan-Ulrich
de la Cruz, Roberto
Dechesne, Arnaud
Smets, Barth F.
Romalde, Jesus L.
Lema, Alberto
Balboa, Sabela
Garcia-Riestra, Carlos
Torres-Sangiao, Eva
Neuberger, Ami
Graham, David
Quintela-Baluja, Marcos
Stekel, Dov J.
Graham, Jay
Pruden, Amy
Nesme, Joseph
Sorenson, Soren Johannes
Hough, Rupert
Paul, Mical
antimicrobial resistance
reporting
recommendations
aquatic
environment
one health
Background: A One Health approach requires integrative research to elucidate antimicrobial resistance (AMR) in the environment and the risks it poses to human health. Research on this topic involves experts from diverse backgrounds and professions. Shortcomings exist in terms of consistent, complete, and transparent reporting in many environmental studies. Standardized reporting will improve the quality of scientific papers, enable meta-analyses and enhance the communication among different experts. In this study, we aimed to generate a consensus of reporting standards for AMR research in wastewater and related aquatic environments.
Methods: Based on a risk of bias assessment of the literature in a systematic review, we proposed a set of study quality indicators. We then used a multistep modified Delphi consensus to develop the EMBRACE-WATERS statement (rEporting antiMicroBial ResistAnCE in WATERS), a checklist of recommendations for reporting in studies of AMR in wastewater and related aquatic environments.
Findings: Consensus was achieved among a multidisciplinary panel of twenty-one experts in three steps. The developed EMBRACE-WATERS statement incorporates 21 items. Each item contains essential elements of high-quality reporting and is followed by an explanation of their rationale and a reporting-example. The EMBRACE-WATERS statement is primarily intended to be used by investigators to ensure transparent and comprehensive reporting of their studies. It can also guide peer-reviewers and editors in evaluation of manuscripts on AMR in the aquatic environment. This statement is not intended to be used to guide investigators on the methodology of their research.
Interpretation: We are hopeful that this statement will improve the reporting quality of future studies of AMR in wastewater and related aquatic environments. Its uptake would generate a common language to be used among researchers from different disciplines, thus advancing the One Health approach towards understanding AMR spread across aquatic environments. Similar initiatives are needed in other areas of One Health research.
2021-10-27T12:18:32Z
2021-10-27T12:18:32Z
2021-12
Article - Refereed
http://hdl.handle.net/10919/106362
https://doi.org/10.1016/j.onehlt.2021.100339
13
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Elsevier
oai:vtechworks.lib.vt.edu:10919/1167282023-12-05T01:59:59Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539com_10919_18738col_10919_105038col_10919_23748col_10919_23145
TUNEOPT: An Evolutionary Reinforcement Learning HVAC Controller For Energy-Comfort Optimization Tuning
Meimand, Mostafa
Khattar, Vanshaj
Yazdani, Zahra
Jazizadeh, Farrokh
Jin, Ming
HVAC systems account for the majority of energy consumption in buildings. Efficient control of HVAC systems can reduce energy consumption and enhance occupants’ comfort. In the existing literature, energy-comfort or cost-comfort co-optimization frameworks commonly involve manual tuning of the balancing coefficient between energy and comfort through parameter tuning by an expert. Nevertheless, achieving the optimal balance between energy usage and occupant comfort remains challenging. This limitation restricts the generalizability of different formulations across various scenarios or testing on different environments. In this paper, we propose an implicit evolutionary Reinforcement Learning (RL) approach to learn and adapt the trade-off parameter of an energy-comfort optimization formulation. We have developed a predictive comfortenergy co-optimization formulation for controlling the setpoint of a building. The RL agent utilizes a novel guidance-induced random search method to learn the energy-comfort trade-off coefficient and guide the optimization formulation. The reward function of the RL model is energy productivity (comfort over energy consumption). To evaluate the feasibility of our proposed approach, we conducted experiments on a real-world testbed - i.e., an apartment unit. Our feasibility study shows that the proposed approach can learn an optimal control parameter and reduce energy consumption by 24.3% while decreasing comfort by only 1% compared to the baseline.
2023-12-04T18:14:17Z
2023-12-04T18:14:17Z
2023-11-15
2023-12-01T08:51:56Z
Article - Refereed
https://hdl.handle.net/10919/116728
https://doi.org/10.1145/3600100.3623751
en
http://creativecommons.org/licenses/by/4.0/
The author(s)
Creative Commons Attribution 4.0 International
ACM
oai:vtechworks.lib.vt.edu:10919/793122021-10-08T16:43:34Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78882col_10919_23748
Characterization of Bitumen Micro-Mechanical Behaviors Using AFM, Phase Dynamics Theory and MD Simulation
Hou, Yue
Wang, Linbing
Wang, Dawei
Guo, Meng
Liu, Pengfei
Yu, Jianxin
Civil and Environmental Engineering
Atomic Force Microscopy
bitumen
micro-mechanical behaviors
Phase Dynamics Theory
MD simulation
Fundamental understanding of micro-mechanical behaviors in bitumen, including phase separation, micro-friction, micro-abrasion, etc., can help the pavement engineers better understand the bitumen mechanical performances at macroscale. Recent researches show that the microstructure evolution in bitumen will directly affect its surface structure and micro-mechanical performance. In this study, the bitumen microstructure and micro-mechanical behaviors are studied using Atomic Force Microscopy (AFM) experiments, Phase Dynamics Theory and Molecular Dynamics (MD) Simulation. The AFM experiment results show that different phase-structure will occur at the surface of the bitumen samples under certain thermodynamic conditions at microscale. The phenomenon can be explained using the phase dynamics theory, where the effects of stability parameter and temperature on bitumen microstructure and micro-mechanical behavior are studied combined with MD Simulation. Simulation results show that the saturates phase, in contrast to the naphthene aromatics phase, plays a major role in bitumen micro-mechanical behavior. A high stress zone occurs at the interface between the saturates phase and the naphthene aromatics phase, which may form discontinuities that further affect the bitumen frictional performance.
2017-09-20T18:30:00Z
2017-09-20T18:30:00Z
2017-02-21
2017-09-20T18:30:00Z
Article - Refereed
Hou, Y.; Wang, L.; Wang, D.; Guo, M.; Liu, P.; Yu, J. Characterization of Bitumen Micro-Mechanical Behaviors Using AFM, Phase Dynamics Theory and MD Simulation. Materials 2017, 10, 208.
http://hdl.handle.net/10919/79312
https://doi.org/10.3390/ma10020208
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/253022023-06-23T15:22:51Zcom_10919_23747com_10919_5539com_10919_23261col_10919_23748col_10919_23262
Entrainment of coarse particles in turbulent flows: An energy approach
Valyrakis, Manousos
Diplas, Panayiotis
Dancey, Clinton L.
Civil and Environmental Engineering
Mechanical Engineering
Bed-load transport
Incipient motion
Sediment entrainment
Pickup probability
Natural rivers
Gravel
Threshold
Water
Movement
Protrusion
The entrainment of coarse sediment particles under the action of fluctuating hydrodynamic forces is investigated from an energy perspective. It is demonstrated that the entrainment of a grain resting on the channel boundary is possible when the instantaneous flow power transferred to it exceeds a critical level. Its complete removal from the bed matrix occurs only if the impinging flow events supply sufficient mechanical energy. The energy-based criterion is formulated theoretically for entrainment of individual spherical particles in both saltation and rolling modes. Out of the wide range of flow events that can perform mechanical work on a coarse grain, only those with sufficient power and duration or equivalent energy density and characteristic length scale may accomplish its complete dislodgement. The instantaneous velocity upstream of a mobile particle is synchronously recorded with its position, enabling the identification of the flow events responsible for grain entrainment by rolling at near incipient motion flow conditions. For each of the entrainment events, the energy transfer coefficient defined as the ratio of the mechanical work performed on the particle to the mean energy of the flow event responsible for its dislodgement obtains values ranging from 0.04 to 0.10. At the examined low-mobility flow conditions, the majority (about 80%) of the energetic structures leading to complete particle entrainment have a characteristic length of about two to four particle diameters.
2014-02-05T14:20:22Z
2014-02-05T14:20:22Z
2013-03-01
2014-01-31
Article - Refereed
Valyrakis, M., P. Diplas, and C. L. Dancey (2013), Entrainment of coarse particles in turbulent flows: An energy approach, J. Geophys. Res. Earth Surf., 118, 42-53, doi:10.1029/2012JF002354.
0148-0227
http://hdl.handle.net/10919/25302
http://onlinelibrary.wiley.com/doi/10.1029/2012JF002354/pdf
https://doi.org/10.1029/2012jf002354
en
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
American Geophysical Union
oai:vtechworks.lib.vt.edu:10919/1142472023-04-05T07:13:19Zcom_10919_23747com_10919_5539col_10919_23748
Minor contributions of daytime monoterpenes are major contributors to atmospheric reactivity
McGlynn, Deborah F.
Frazier, Graham
Barry, Laura E. R.
Lerdau, Manuel T.
Pusede, Sally E.
Isaacman-VanWertz, Gabriel
Volatile organic-compounds
gas-phase reactions
positive matrix factorization
rate constants
de-novo
emissions
isoprene
light
sesquiterpenes
oh
Emissions from natural sources are driven by various external stimuli such as sunlight, temperature, and soil moisture. Once biogenic volatile organic compounds (BVOCs) are emitted into the atmosphere, they rapidly react with atmospheric oxidants, which has significant impacts on ozone and aerosol budgets. However, diurnal, seasonal, and interannual variability in these species are poorly captured in emissions models due to a lack of long-term, chemically speciated measurements. Therefore, increasing the monitoring of these emissions will improve the modeling of ozone and secondary organic aerosol concentrations. Using 2 years of speciated hourly BVOC data collected at the Virginia Forest Research Lab (VFRL) in Fluvanna County, Virginia, USA, we examine how minor changes in the composition of monoterpenes between seasons are found to have profound impacts on ozone and OH reactivity. The concentrations of a range of BVOCs in the summer were found to have two different diurnal profiles, which, we demonstrate, appear to be driven by light-dependent versus light-independent emissions. Factor analysis was used to separate the two observed diurnal profiles and determine the contribution from each emission type. Highly reactive BVOCs were found to have a large influence on atmospheric reactivity in the summer, particularly during the daytime. These findings reveal the need to monitor species with high atmospheric reactivity, even though they have low concentrations, to more accurately capture their emission trends in models.
2023-04-04T15:06:25Z
2023-04-04T15:06:25Z
2023-01-04
Article - Refereed
http://hdl.handle.net/10919/114247
https://doi.org/10.5194/bg-20-45-2023
20
1
1726-4189
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Copernicus
oai:vtechworks.lib.vt.edu:10919/817862023-06-23T15:22:55Zcom_10919_5com_10919_25799com_10919_78629com_10919_78628com_10919_23747com_10919_5539col_10919_70873col_10919_78630col_10919_23748
Tracking of a Fluorescent Dye in a Freshwater Lake with an Unmanned Surface Vehicle and an Unmanned Aircraft System
Powers, Craig W.
Schmale, David G. III
Hanlon, Regina
Civil and Environmental Engineering
Recent catastrophic events in our oceans, including the spill of toxic oil from the explosion of the Deepwater Horizon drilling rig and the rapid dispersion of radioactive particulates from the meltdown of the Fukushima Daiichi nuclear plant, underscore the need for new tools and technologies to rapidly respond to hazardous agents. Our understanding of the movement and aerosolization of hazardous agents from natural aquatic systems can be expanded upon and used in prevention and tracking. New technologies with coordinated unmanned robotic systems could lead to faster identification and mitigation of hazardous agents in lakes, rivers, and oceans. In this study, we released a fluorescent dye (fluorescein) into a freshwater lake from an anchored floating platform. A fluorometer (fluorescence sensor) was mounted underneath an unmanned surface vehicle (USV, unmanned boat) and was used to detect and track the released dye in situ in real-time. An unmanned aircraft system (UAS) was used to visualize the dye and direct the USV to sample different areas of the dye plume. Image processing tools were used to map concentration profiles of the dye plume from aerial images acquired from the UAS, and these were associated with concentration measurements collected from the sensors onboard the USV. The results of this project have the potential to transform monitoring strategies for hazardous agents, enabling timely and accurate exposure assessment and response in affected areas. Fast response is essential in reacting to the introduction of hazardous agents, in order to quickly predict and contain their spread.
2018-01-15T18:55:14Z
2018-01-15T18:55:14Z
2018-01-09
Article - Refereed
Powers, C.; Hanlon, R.; Schmale, D.G., III. Tracking of a Fluorescent Dye in a Freshwater Lake with an Unmanned Surface Vehicle and an Unmanned Aircraft System. Remote Sens. 2018, 10, 81.
http://hdl.handle.net/10919/81786
https://doi.org/10.3390/rs10010081
10 (1)
81
Schmale, DG [0000-0002-7003-7429]
en
http://www.mdpi.com/2072-4292/10/1/81
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
oai:vtechworks.lib.vt.edu:10919/1087802022-02-22T08:12:02Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_18629col_10919_23748
Demonstrating a systems approach for integrating disparate data streams to inform decisions on children’s environmental health
Hubal, Elaine A. C.
DeLuca, Nicole M.
Mullikin, Ashley
Slover, Rachel
Little, John C.
Reif, David M.
Background
The use of systems science methodologies to understand complex environmental and human health relationships is increasing. Requirements for advanced datasets, models, and expertise limit current application of these approaches by many environmental and public health practitioners.
Methods
A conceptual system-of-systems model was applied for children in North Carolina counties that includes example indicators of children’s physical environment (home age, Brownfield sites, Superfund sites), social environment (caregiver’s income, education, insurance), and health (low birthweight, asthma, blood lead levels). The web-based Toxicological Prioritization Index (ToxPi) tool was used to normalize the data, rank the resulting vulnerability index, and visualize impacts from each indicator in a county. Hierarchical clustering was used to sort the 100 North Carolina counties into groups based on similar ToxPi model results. The ToxPi charts for each county were also superimposed over a map of percentage county population under age 5 to visualize spatial distribution of vulnerability clusters across the state.
Results
Data driven clustering for this systems model suggests 5 groups of counties. One group includes 6 counties with the highest vulnerability scores showing strong influences from all three categories of indicators (social environment, physical environment, and health). A second group contains 15 counties with high vulnerability scores driven by strong influences from home age in the physical environment and poverty in the social environment. A third group is driven by data on Superfund sites in the physical environment.
Conclusions
This analysis demonstrated how systems science principles can be used to synthesize holistic insights for decision making using publicly available data and computational tools, focusing on a children’s environmental health example. Where more traditional reductionist approaches can elucidate individual relationships between environmental variables and health, the study of collective, system-wide interactions can enable insights into the factors that contribute to regional vulnerabilities and interventions that better address complex real-world conditions.
2022-02-21T12:34:05Z
2022-02-21T12:34:05Z
2022-02-15
2022-02-20T04:19:28Z
Article - Refereed
BMC Public Health. 2022 Feb 15;22(1):313
http://hdl.handle.net/10919/108780
https://doi.org/10.1186/s12889-022-12682-3
en
http://creativecommons.org/licenses/by/4.0/
The Author(s)
Creative Commons Attribution 4.0 International
oai:vtechworks.lib.vt.edu:10919/1108272022-06-18T07:12:28Zcom_10919_23747com_10919_5539col_10919_23748
Ozone disinfection of waterborne pathogens and their surrogates: A critical review
Morrison, Christina M.
Hogard, Samantha
Pearce, Robert
Gerrity, Daniel
Wert, Eric C.
von Gunten, Urs
Ozone
Disinfection
Cryptosporidium
Giardia
Virus
Pathogen
Viruses, Giardia cysts, and Cryptosporidium parvum oocysts are all major causes of waterborne diseases that can be uniquely challenging in terms of inactivation/removal during water and wastewater treatment and water reuse. Ozone is a strong disinfectant that has been both studied and utilized in water treatment for more than a century. Despite the wealth of data examining ozone disinfection, direct comparison of results from different studies is challenging due to the complexity of aqueous ozone chemistry and the variety of the applied approaches. In this systematic review, an analysis of the available ozone disinfection data for viruses, Giardia cysts, and C. parvum oocysts, along with their corresponding surrogates, was performed. It was based on studies implementing procedures which produce reliable and comparable datasets. Datasets were compiled and compared with the current USEPA Ct models for ozone. Additionally, the use of non-pathogenic surrogate organisms for prediction of pathogen inactivation during ozone disinfection was evaluated. Based on second-order inactivation rate constants, it was determined that the inactivation efficiency of ozone decreases in the following order: Viruses >> Giardia cysts > C. parvum oocysts. The USEPA Ct models were found to be accurate to conservative in predicting inactivation of C. parvum oocysts and viruses, respectively, however they overestimate inactivation of Giardia cysts at ozone Ct values greater than ~1 mg min L-1. Common surrogates of these pathogens, such as MS2 bacterio-phage and Bacillus subtilis spores, were found to exhibit different inactivation kinetics to mammalian viruses and C. parvum oocysts, respectively. The compilation of data highlights the need for further studies on disinfection kinetics and inactivation mechanisms by ozone to better fit inactivation models as well as for proper selection of surrogate organisms.
2022-06-17T12:48:55Z
2022-06-17T12:48:55Z
2022-05-01
Article - Refereed
0043-1354
118206
http://hdl.handle.net/10919/110827
https://doi.org/10.1016/j.watres.2022.118206
214
35276607
1879-2448
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Pergamon-Elsevier
oai:vtechworks.lib.vt.edu:10919/1137132023-11-29T16:13:45Zcom_10919_5com_10919_25799com_10919_5524com_10919_23747com_10919_5539col_10919_70873col_10919_113712col_10919_23748
NeTrainSim: A Network Freight Train Simulator for Estimating Energy/Fuel Consumption
Aredah, Ahmed
Fadhloun, Karim
Rakha, Hesham A.
List, George
Although train simulation research is vast, most available network simulators do not track the instantaneous movements and interactions of multiple trains for the computation of energy/fuel consumption. In this paper, we introduce the NeTrainSim simulator for heavy long-haul freight trains on a network of multiple intersecting tracks. Trains are modeled as a series of moving mass points (each car/locomotive is modeled as a point mass) while ensuring safe following distances between them. The simulator considers the motion of the train as a whole and neglects the relative movements between the train cars/locomotives. Furthermore, the powers of the different locomotives are transferred to the first locomotive as such a simplification result in a reduced simulation time without impacting the accuracy of energy consumption estimates. While the different tractive forces are combined, the resistive forces are calculated at their corresponding locations. The output files of the simulator contain pertaining information to the train trajectories and the instantaneous energy consumption levels. A summary file is also provided with the total energy consumed for the full trip and the entire network of trains. Two case studies are conducted to demonstrate the performance of the simulator. The first case study validates the model by comparing the output of NeTrainSim to empirical trajectory data using a basic single-train network. The results confirm that the simulated trajectory is precise enough to estimate the electric energy consumption of the train. The second case study demonstrates the train-following model considering six trains following each other. The results showcase the model’s ability in relation to maintaining safe-following distances between successive trains. Finally, the NeTrainSim is demonstrated to be scalable with computational times of O(n) for less than 50 trains (n) and O(n2) for higher number of trains.
2023-02-07T20:03:29Z
2023-02-07T20:03:29Z
2023-01-10
2023-02-07T18:57:19Z
Conference proceeding
http://hdl.handle.net/10919/113713
Rakha, Hesham [0000-0002-5845-2929]
en
102nd Transportation Research Board Annual Meeting
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
oai:vtechworks.lib.vt.edu:10919/1111572022-07-08T07:13:24Zcom_10919_23747com_10919_5539col_10919_23748
Derivation of a near-surface damping model for the Groningen gas field
Ruigrok, E.
Rodriguez-Marek, Adrian
Edwards, B.
Kruiver, P. P.
Dost, B.
Bommer, J.
Downhole methods
Induced seismicity
Seismic attenuation
Seismic interferometry
Site effects
Wave scattering and diffraction
Seismic damping of near-surface deposits is an important input to site-response analysis for seismic hazard assessment. In Groningen, the Netherlands, gas production from a reservoir at 3 km depth causes seismicity. Above the gas field, an 800 m thick layer of unconsolidated sediments exist, which consists of a mixture of sand, gravel, clay and peat strata. Shear waves induced at 3 km depth experience most of their anelastic attenuation in these loose sediments. A good estimate of damping is therefore crucial for modelling realistic ground-motion levels. In Groningen, we take advantage of a large network of 200 m deep vertical arrays to estimate damping from recordings of the induced events. As a first step, we apply seismic interferometry by deconvolution to estimate local transfer functions over these vertical arrays. Subsequently, two different methods are employed. The first is the 'upgoing' method, where the amplitude decay of the retrieved upgoing wave is used. The second is the 'up-down' method, where the amplitude difference between retrieved up- and downgoing waves is utilized. For the upgoing method, the amplitude of the upgoing direct wave is affected by both elastic and anelastic effects. In order to estimate the anelastic attenuation, it is necessary to remove the elastic amplification first. Despite the fact that elastic compensation could be determined quite accurately, non-physical damping values were estimated for a number of boreholes. Likely, the underlying cause was small differences in effective response functions of geophones at different depths. It was found that the up-down method is more robust. With this method, elastic propagation corrections are not needed. In addition, small differences in in situ geophone response are irrelevant because the up- and downgoing waves retrieved at the same geophone are used. For the 1-D case, we showed that for estimating the local transfer function, the complex reverberations need to be included in the interferometric process. Only when this is done, the transfer function does not contain elastic transmission loss and Q estimation can be made without knowing the soil profile in detail. Uncertainty in the estimated damping was found from the signal-to-noise ratio of the estimated transfer function. The Q profiles estimated with the up-down method were used to derive a damping model for the top 200 m of the entire Groningen field. A scaling relation was derived by comparing estimated Q profiles with low-strain damping profiles that were constructed using published models for low-strain damping linked to soil properties. This scaling relation, together with the soil-property-based damping model, allowed up-scaling of the model to each grid-cell in the Groningen field. For depths below 200 m, damping was derived from the attenuation of the microseism over Groningen. The mean damping model, over a frequency band between 2 and 20 Hz, was estimated to be 2.0 per cent (0-50 m depth), 1.3 per cent (50-100 m), 0.66 per cent (100-150 m), 0.57 per cent (150-200 m) and 0.5 per cent (200-580 m).
2022-07-07T14:51:06Z
2022-07-07T14:51:06Z
2022-04-13
Article - Refereed
0956-540X
http://hdl.handle.net/10919/111157
https://doi.org/10.1093/gji/ggac069
230
2
1365-246X
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
Oxford University Press
oai:vtechworks.lib.vt.edu:10919/799162023-06-23T15:22:49Zcom_10919_78629com_10919_78628com_10919_23747com_10919_5539col_10919_79524col_10919_23748
Forecasting Model for Air Taxi, Commercial Airline, and Automobile Demand in the United States
Baik, Hojong
Trani, Antonio A.
Hinze, Nicolas
Swingle, Howard
Ashiabor, Senanu
Seshadri, Anand
Civil and Environmental Engineering
A nationwide model predicts the annual county-to-county person roundtrips for air taxi, commercial airline, and automobile at 1-year intervals through 2030. The transportation systems analysis model (TSAM) uses the four-step transportation systems modeling process to calculate trip generation, trip distribution, and mode choice for each county origin–destination pair. Network assignment is formulated for commercial airline and air taxi demand. TSAM classifies trip rates by trip purpose, household income group, and type of metropolitan statistical area from which the round-trip started. A graphical user interface with geographic information systems capability is included in the model. Potential applications of the model are nationwide impact studies of transportation policies and technologies, such as those envisioned with the introduction of extensive air taxi service using very light jets, the next-generation air transportation system, and the introduction of new aerospace technologies.
2017-11-02T13:44:08Z
2017-11-02T13:44:08Z
2008
Article - Refereed
http://hdl.handle.net/10919/79916
https://doi.org/10.3141/2052-02
2052
en
http://rightsstatements.org/vocab/InC/1.0/
In Copyright
Transportation Research Board of the National Academies
oai:vtechworks.lib.vt.edu:10919/937402022-02-25T02:39:53Zcom_10919_23747com_10919_5539col_10919_23748
Characterisation of the Groningen subsurface for seismic hazard and risk modelling
Kruiver, Pauline P.
Wiersma, Ane
Kloosterman, Fred H.
de Lange, Ger
Korff, Mandy
Stafleu, Jan
Busschers, Freek S.
Harting, Ronald
Gunnink, Jan L.
Green, Russell A.
van Elk, Jan
Doornhof, Dirk
Civil and Environmental Engineering
geology
liquefaction
microzonation
site response
soil properties
The shallow subsurface of Groningen, the Netherlands, is heterogeneous due to its formation in a Holocene tidal coastal setting on a periglacially and glacially inherited landscape with strong lateral variation in subsurface architecture. Soft sediments with low, small-strain shear wave velocities (VS30 around 200ms(-1)) are known to amplify earthquake motions. Knowledge of the architecture and properties of the subsurface and the combined effect on the propagation of earthquake waves is imperative for the prediction of geohazards of ground shaking and liquefaction at the surface. In order to provide information for the seismic hazard and risk analysis, two geological models were constructed. The first is the ` Geological model for Site response in Groningen' (GSG model) and is based on the detailed 3D GeoTOP voxel model containing lithostratigraphy and lithoclass attributes. The GeoTOP model was combined with information from boreholes, cone penetration tests, regional digital geological and geohydrological models to cover the full range from the surface down to the base of the North Sea Supergroup (base Paleogene) at similar to 800m depth. The GSG model consists of a microzonation based on geology and a stack of soil stratigraphy for each of the 140,000 grid cells (100m x 100 m) to which properties (VS and parameters relevant for nonlinear soil behaviour) were assigned. The GSG model serves as input to the site response calculations that feed into the Ground Motion Model. The second model is the ` Geological model for Liquefaction sensitivity in Groningen' (GLG). Generally, loosely packed sands might be susceptible to liquefaction upon earthquake shaking. In order to delineate zones of loosely packed sand in the first 40m below the surface, GeoTOP was combined with relative densities inferred from a large cone penetration test database. The marine Naaldwijk and Eem Formations have the highest proportion of loosely packed sand (31% and 38%, respectively) and thus are considered to be the most vulnerable to liquefaction; other units contain 5-17% loosely packed sand. The GLG model serves as one of the inputs for further research on the liquefaction potential in Groningen, such as the development of region-specific magnitude scaling factors (MSF) and depth-stress reduction relationships (r(d)).
2019-09-17T19:20:04Z
2019-09-17T19:20:04Z
2017-12
Article - Refereed
0016-7746
http://hdl.handle.net/10919/93740
https://doi.org/10.1017/njg.2017.11
96
5
1573-9708
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
oai:vtechworks.lib.vt.edu:10919/1116022022-08-24T07:13:46Zcom_10919_23747com_10919_5539col_10919_23748
Sustainable treatment of nitrate-containing wastewater by an autotrophic hydrogen-oxidizing bacterium
Chen, Yi-Zhen
Zhang, Li-Juan
Ding, Ling-Yun
Zhang, Yao-Yu
Wang, Xi-Song
Qiao, Xue-Jiao
Pan, Bao-Zhu
Wang, Zhi-Wu
Xu, Nan
Tao, Hu-Chun
Wastewater
Nitrate
Hydrogen-oxidizing bacteria
Autotrophic assimilation
Aerobic denitrification
Bacteria are key denitrifiers in the reduction of nitrate (NO3--N), which is a contaminant in wastewater treatment plants (WWTPs). They can also produce carbon dioxide (CO2) and nitrous oxide (N2O). In this study, the autotrophic hydrogen-oxidizing bacterium Rhodoblastus sp. TH20 was isolated for sustainable treatment of NO3--N in wastewater. Efficient removal of NO3--N and recovery of biomass nitrogen were achieved. Up to 99% of NO3--N was removed without accumulation of nitrite and N2O, consuming CO2 of 3.25 mol for each mole of NO3--N removed. The overall removal rate of NO3--N reached 1.1 mg L-1 h(-1) with a biomass content of approximately 0.71 g L-1 within 72 h. TH20 participated in NO3--N assimilation and aerobic denitrification. Results from N-15-labeled-nitrate test indicated that removed NO3--N was assimilated into organic nitrogen, showing an assimilation efficiency of 58%. Seventeen amino acids were detected, accounting for 43% of the biomass. Nitrogen loss through aerobic denitrification was only approximately 42% of total nitrogen. This study suggests that TH20 can be applied in WWTP facilities for water purification and production of valuable biomass to mitigate CO2 and N2O emissions. (C) 2022 Published by Elsevier B.V. on behalf of Chinese Society for Environmental Sciences, Harbin Institute of Technology, Chinese Research Academy of Environmental Sciences.
2022-08-23T13:48:39Z
2022-08-23T13:48:39Z
2022-01
Article - Refereed
2666-4984
100146
http://hdl.handle.net/10919/111602
https://doi.org/10.1016/j.ese.2022.100146
9
en
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Elsevier
oai:vtechworks.lib.vt.edu:10919/1112342022-07-14T07:12:38Zcom_10919_23747com_10919_5539com_10919_24215col_10919_23748col_10919_24289
Using Learning Analytics and Student Perceptions to Explore Student Interactions in an Online Construction Management Course
West, Paige
Paige, Frederick
Lee, Walter C.
Watts, Natasha
Scales, Glenda R.
Engineering education
Online courses
Learning analytics
Student interaction
The expansion of online learning in higher education has both contributed to researchers exploring innovative ways to develop learning environments and created challenges in identifying student interactions with course material. Learning analytics is an emerging field that can identify student interactions and help make data-informed course design decisions. In this case study, learning analytics were collected from 113 students in three course sections of an online construction management course in the Canvas learning management system (LMS). Surveys were used to collect students’ perceptions of the course design and materials to correlate with the students’ interactions with the course materials. The survey findings showed the students found watching the lecture videos and reading the lecture slides to be the most helpful aspects of the course materials in their learning. Findings from the learning analytics showed that students’ interactions with the course decreased after the midterm exam. Based on the results, online course instructors can leverage their learning analytics to understand student interactions and make data-informed course design changes to improve their online learning environments.
2022-07-13T18:31:51Z
2022-07-13T18:31:51Z
2022-10
Article - Refereed
http://hdl.handle.net/10919/111234
https://doi.org/10.1061/(ASCE)EI.2643-9115.0000066
148
4
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
ASCE
oai:vtechworks.lib.vt.edu:10919/1028772021-10-08T16:43:34Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539col_10919_78882col_10919_23748
Finite Element Modeling and Performance Evaluation of Piezoelectric Energy Harvesters with Various Piezoelectric Unit Distributions
Du, Cong
Liu, Pengfei
Yang, Hailu
Jiang, Gengfu
Wang, Linbing
Oeser, Markus
Civil and Environmental Engineering
piezoelectric energy harvester
finite element simulation
piezoelectric unit distributions
electrical potential and energy
von Mises stress
The piezoelectric energy harvester (PEH) is a device for recycling wasted mechanical energy from pavements. To evaluate energy collecting efficiency of PEHs with various piezoelectric unit distributions, finite element (FE) models of the PEHs were developed in this study. The PEH was a square of 30 cm × 30 cm with 7 cm in thickness, which was designed according to the contact area between tire and pavement. Within the PEHs, piezoelectric ceramics (PZT-5H) were used as the core piezoelectric units in the PEHs. A total of three distributions of the piezoelectric units were considered, which were 3 × 3, 3 × 4, and 4 × 4, respectively. For each distribution, two diameters of the piezoelectric units were considered to investigate the influence of the cross section area. The electrical potential, total electrical energy and maximum von Mises stress were compared based on the computational results. Due to the non-uniformity of the stress distribution in PEHs, more electrical energy can be generated by more distributions and smaller diameters of the piezoelectric units; meanwhile, more piezoelectric unit distributions cause a higher electrical potential difference between the edge and center positions. For the same distribution, the piezoelectric units with smaller diameter produce higher electrical potential and energy, but also induce higher stress concentration in the piezoelectric units near the edge.
2021-03-30T12:39:31Z
2021-03-30T12:39:31Z
2021-03-14
2021-03-26T14:06:08Z
Article - Refereed
Du, C.; Liu, P.; Yang, H.; Jiang, G.; Wang, L.; Oeser, M. Finite Element Modeling and Performance Evaluation of Piezoelectric Energy Harvesters with Various Piezoelectric Unit Distributions. Materials 2021, 14, 1405.
http://hdl.handle.net/10919/102877
https://doi.org/10.3390/ma14061405
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/983962023-11-29T16:17:37Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539com_10919_5524col_10919_78882col_10919_23748col_10919_89575
Battery Electric Vehicle Eco-Cooperative Adaptive Cruise Control in the Vicinity of Signalized Intersections
Chen, Hao
Rakha, Hesham A.
Civil and Environmental Engineering
Virginia Tech Transportation Institute
eco-driving
battery electric vehicles
signalized intersections
energy-optimized vehicle trajectories
vehicle dynamics model
This study develops a connected eco-driving controller for battery electric vehicles (BEVs), the BEV Eco-Cooperative Adaptive Cruise Control at Intersections (Eco-CACC-I). The developed controller can assist BEVs while traversing signalized intersections with minimal energy consumption. The calculation of the optimal vehicle trajectory is formulated as an optimization problem under the constraints of (1) vehicle acceleration/deceleration behavior, defined by a vehicle dynamics model; (2) vehicle energy consumption behavior, defined by a BEV energy consumption model; and (3) the relationship between vehicle speed, location, and signal timing, defined by vehicle characteristics and signal phase and timing (SPaT) data shared under a connected vehicle environment. The optimal speed trajectory is computed in real-time by the proposed BEV eco-CACC-I controller, so that a BEV can follow the optimal speed while negotiating a signalized intersection. The proposed BEV controller was tested in a case study to investigate its performance under various speed limits, roadway grades, and signal timings. In addition, a comparison of the optimal speed trajectories for BEVs and internal combustion engine vehicles (ICEVs) was conducted to investigate the impact of vehicle engine types on eco-driving solutions. Lastly, the proposed controller was implemented in microscopic traffic simulation software to test its networkwide performance. The test results from an arterial corridor with three signalized intersections demonstrate that the proposed controller can effectively reduce stop-and-go traffic in the vicinity of signalized intersections and that the BEV Eco-CACC-I controller produces average savings of 9.3% in energy consumption and 3.9% in vehicle delays.
2020-05-14T17:49:58Z
2020-05-14T17:49:58Z
2020-05-12
2020-05-14T13:56:25Z
Article - Refereed
Chen, H.; Rakha, H.A. Battery Electric Vehicle Eco-Cooperative Adaptive Cruise Control in the Vicinity of Signalized Intersections. Energies 2020, 13, 2433.
http://hdl.handle.net/10919/98396
https://doi.org/10.3390/en13102433
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
oai:vtechworks.lib.vt.edu:10919/1152112023-05-27T07:14:32Zcom_10919_8195com_10919_25799com_10919_23747com_10919_5539com_10919_19035com_10919_111113col_10919_78882col_10919_23748col_10919_24290col_10919_111114
A Mycorrhizal Model for Transactive Solar Energy Markets with Battery Storage
Gould, Zachary Michael Isaac
Mohanty, Vikram
Reichard, Georg
Saad, Walid
Shealy, Tripp
Day, Susan
Distributed market structures for local, transactive energy trading can be modeled with ecological systems, such as mycorrhizal networks, which have evolved to facilitate interplant carbon exchange in forest ecosystems. However, the complexity of these ecological systems can make it challenging to understand the effect that adopting these models could have on distributed energy systems and the magnitude of associated performance parameters. We therefore simplified and implemented a previously developed blueprint for mycorrhizal energy market models to isolate the effect of the mycorrhizal intervention in allowing buildings to redistribute portions of energy assets on competing local, decentralized marketplaces. Results indicate that the applied mycorrhizal intervention only minimally affects market and building performance indicators—increasing market self-consumption, decreasing market self-sufficiency, and decreasing building weekly savings across all seasonal (winter, fall, summer) and typological (residential, mixed-use) cases when compared to a fixed, retail feed-in-tariff market structure. The work concludes with a discussion of opportunities for further expansion of the proposed mycorrhizal market framework through reinforcement learning as well as limitations and policy recommendations considering emerging aggregated distributed energy resource (DER) access to wholesale energy markets.
2023-05-26T14:26:14Z
2023-05-26T14:26:14Z
2023-05-13
2023-05-26T13:20:35Z
Article - Refereed
Gould, Z.M.I.; Mohanty, V.; Reichard, G.; Saad, W.; Shealy, T.; Day, S. A Mycorrhizal Model for Transactive Solar Energy Markets with Battery Storage. Energies 2023, 16, 4081.
http://hdl.handle.net/10919/115211
https://doi.org/10.3390/en16104081
en
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International
MDPI
rdf///col_10919_23748/100