Scholarly Works, Sustainable Biomaterials
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- Efficacy of a Rose Bengal-Embedded Antimicrobial Packaging Film in Inactivating Escherichia coli under Visible Light IrradiationJohnson, Andrea; Wu, Jian; Zhou, Zhe; Li, Yilin; Yin, Yun; Ponder, Monica A.; Kim, Young-Teck; Shuai, Danmeng; Huang, Haibo (American Chemical Society, 2024-02-24)Antimicrobial packaging reduces the extent of microbial contamination; however, conventional antimicrobial packaging, which releases antimicrobial agents into food, may experience rapid agent depletion and can adversely affect food flavors. In this study, a novel photocatalytic antimicrobial nanofiber film embedded with Rose Bengal (RB) dye that generates reactive oxygen species (ROS) in visible light was designed for inactivating microorganisms. The film’s antimicrobial properties under various light intensities and exposure times were evaluated, using Escherichia coli as a test microorganism. The results demonstrated that RB generates singlet oxygen as its principal ROS and has potent antimicrobial effects when incorporated into a film, achieving a 4.4 ± 0.1 log CFU reduction in E. coli after 45 h under a light intensity of 6500 lx. The film’s antimicrobial efficacy was dependent on light intensity, with significant E. coli inactivation occurring above 2000 lx. Overall, the RB-incorporated film effectively inactivates E. coli, providing a promising alternative to conventional antimicrobial packaging methods.
- Prediction of equilibrium moisture content and swelling of thermally modified hardwoods by Artificial Neural NetworksMasoumi, Abasali; Bond, Brian H. (North Carolina State University, 2024)In this study artificial neural network (ANN) models were developed for predicting the effects of wood species, density, modifying time, and temperature on the equilibrium moisture content (EMC) and swelling of six different thermally modified hardwood species, as previously published by the authors. Lumber of Yellow-poplar (Liriodendron tulipifera), red oak (Quercus borealis), white ash (Fraxinus americana), red maple (Acer rubrum), hickory (Carya glabra), and black cherry (Prunus serotina) were selected. Treatment type, species, temperature, time, and density were used as inputs for the models. Using Keras and Pytorch libraries in Python, different feed forward and back propagation multilayer ANN models were created and tested. The best prediction models, determined based on the errors in training iterations, were selected and used for testing. Based on the performance analysis, the prediction ANN models were accurate, reliable, and effective tools in terms of time and cost-effectiveness, for predicting the EMC and swelling characteristics of thermally modified wood. The multiple-input model was more accurate than the single-input model and it provided a prediction with R² of 0.9975, 0.92, and MAPE of 1.36, 7.77 for EMC and swelling.
- Impacts of cycles of a novel low-pressure homogenization process on cellulose nanofibrils (CNF) as a sustainable packaging film materialLovely, Belladini; Kim, Young-Teck; Huang, Haibo; Zink-Sharp, Audrey; Roman, Maren (Elsevier, 2025-03-04)Cellulose nanofibrils (CNF) have been among the most researched materials for their myriad advantages, yet are still facing challenges toward advanced developments due to their natural hydrophilicity affecting a broad range of properties. A simple, mildly-conditioned (low pressure at 7 MPa, for 0–25 cycles) homogenization approach was explored, and its effects on the Northern bleached softwood based-CNF films’ functional properties were investigated. Post-homogenization, promoted hydrogen bonding and fibrillation were evidenced by FTIR and surface SEM, respectively. A maintained high crystallinity (64 %) and smoother surface of homogenized CNF films (Sa, 2.64 from 4.73 μm) compared to the untreated CNF films was also achieved. The resulting decrease in oxygen permeability (0.25 from 0.48 cc.μm/m2.day.kPa, at 50 %RH) is comparable to the reference values of the commercial oxygen barrier resin brand of ethylene-vinyl alcohol (EVOH). Significant improvements in mechanical (tensile strength, 157 from 94 MPa; Young’s modulus, 3843 from 2630 MPa; and elongation-at-break, 7.59 from 5.69 %) and thermal (elastic modulus, loss modulus, damping factor, and degradation temperature) properties were confirmed. Contact angle improvement (0–60 s) was also obtained. With varying optimum homogenization cycles, this work demonstrates the prospect of a straightforward, cheap, and environmentally friendly approach in modifying CNF with enhanced processability and applicability for diverse applications.
- Exploring Backcasting as a Tool to Co-create a Vision for a Circular Economy: A Case Study of the Polyurethane Foam IndustryAbadian, Mona; Russell, Jennifer D. (DSRPT GbR, 2024-05-21)The pursuit of Circular Economy (CE) principles in industrial activities is crucial for mitigating environmental impacts, particularly in relation to plastic consumption and waste. While desirable, such a transition is incredibly challenging for many industries. Using the polyurethane (PU) foam industry as a starting point, a participatory planning process called backcasting was used to engage diverse stakeholders and explore the potential for CE implementation and transition. Usually applied in policy-making contexts, this study used a particular approach (“ABCD-method”) to facilitate a workshop of industry representatives from across the PU foam value chain: recyclers, chemical suppliers, manufacturers, academia, and governments. Through the process, participants discussed, developed and agreed upon 78 CE Pathways, categorizing these as short-, mid-, and/or long-term priorities, and assigning them to respective and appropriate PU foam value chain members. These co-created CE Pathway priorities, such as the development of industry-wide material specifications, simplified chemical formulations, and innovation in feedstock sourcing, may contribute to increased industry awareness about potential opportunities for transition to the CE within PU foam value chain. CE Pathway priorities from this work are informing the strategic roadmap for the PU foam industry’s transition to CE. Further, this work suggests the efficacy of participatory backcasting as a potential method for facilitating voluntary industry discussion and visioning across diverse sectors and value-chains.
- Optimizing Lumber Densification for Mitigating Rolling Shear Failure in Cross-Laminated Timber (CLT)Pradhan, Suman; Mohammadabadi, Mostafa; Seale, Roy Daniel; Thati, Manikanta; Entsminger, Edward D.; Nkeuwa, William Nguegang (MDPI, 2024-04-04)Rolling shear in cross-laminated timber (CLT) has been identified as the governing factor influencing design value. Likewise, densification has been found to be an effective method of enhancing the rolling shear strength of lumber and in turn, CLT. In this study, utilizing knowledge of material properties, optimization of the compression ratio for densification has been presented. Three-layered CLT beams made from non-densified lumber, grade #1 loblolly pine (Pinus taeda L.), were subjected to a bending load at a span-to-depth ratio of eight and had a rolling shear failure at the mid-layer with a shear strength of 3 MPa. Assuming the same modulus of rupture (MOR) for both lumber and CLT made from the same species and grade, the MOR of lumber was used to calculate the minimum required shear strength (MRSS) of the transverse mid-layer to change the failure mode of the CLT beam from rolling shear to tensile failure. Using the relationship between the compression ratio and the increase in rolling shear strength, the optimized compression ratio for densification was calculated. This procedure resulted in a compression ratio of 16.67% for densification of the mid-layer to avoid rolling shear in the case of CLT beams with a span-to-depth ratio of eight. To verify this process, CLT beams with mid-layers densified at 16.67% were fabricated and submitted to a bending test. Rolling shear failure was mitigated and densified CLT beams failed in tension with a MOR similar to that of lumber, 47.45 MPa. Likewise, rolling shear strength was observed to increase by 48% for CLT that had a densified mid-layer at 16.67%.
- Measurement and Analysis of the Shock and Drop Levels Experienced by Small and Medium Packages in the Korean Parcel Delivery SystemKim, Saewhan; Horvath, Laszlo; Lee, Sangwook (MDPI, 2024-05-08)South Korea is one of the leading markets for the e-commerce industry. In line with the rapid growth of the e-commerce industry, the parcel delivery volume in Korea has also proliferated. Despite the developments in the Korean e-commerce and courier industries, consumers still experience a high package damage rate. In response, many packaging engineers in Korea have raised the need for new parcel shipping environment tests that reflect the Korean ground shipping environment in order to properly optimize packages. However, only limited information on the Korean parcel shipping environment is currently available. Therefore, this study focused on measuring and analyzing the shock and drop levels that parcels experience during ground shipping in Korea. Shock data were collected from a total of sixty one-way shipments for small, lightweight packages and medium, mid-weight packages. The findings revealed that the two types of boxes do not experience significantly different numbers of shock events or drop heights in the Korean parcel delivery environment. Furthermore, the number of shock events that occur in Korea is substantially less than the international testing standard and less than in previous studies conducted in both Europe and the USA. In contrast, however, the drop heights are higher than those in the international testing standard and previous studies. Shock events were found to occur most frequently on the edges and to be concentrated around the bottoms of the packages. Most shock events happen while packages are loaded and unloaded at hub terminals and sub terminals.
- Analysis of Deformation Fixation of Thermally Compressed Scots Pine (Pinus sylvestris L.)Li, Lili; Shan, Xiaofei; Luo, Zhiying; Liu, Wenwen; Liu, Jianxia; Yu, Jianfang; Chen, Zhangjing; Wang, Ximing (MDPI, 2024-05-11)Heat treatment effectively inhibits the water absorption recovery of compressed wood. To elucidate this phenomenon, we prepared compressed pine and thermally compressed pine (heartwood and sapwood) using the hot pressing method at 160 °C, 180 °C, 200 °C, and 220 °C. The effects of chemical components, swelling stresses, and monosaccharides on modified wood recovery were investigated using regression analyses. Notably, the recovery of both compressed heartwood and sapwood during water absorption declined from 18.89% to 2.66% and from 58.40% to 1.60%, respectively, after heat treatment. Similarly, the swelling stresses of the compressed heartwood and sapwood at 220 °C, respectively, ranged from 0.693 MPa to 0.275 MPa and from 0.783 MPa to 0.330 MPa. These were close to the values of untreated heartwood (0.175 MPa) and sapwood (0.225 MPa). Regression functions indicated that the recovery of compressed wood is chemically dependent on hemicellulose and mechanically related to swelling stress. For monosaccharides, regression functions indicated that modified heartwood recovery primarily relied on mannose, whereas modified sapwood recovery was remarkably affected by mannose and xylose. This confirmed that the pyrolytic monosaccharides in hemicellulose promoted stress relaxation, which induced the deformation fixation of thermally compressed wood.
- Measurement and Analysis of Last-Mile Parcel Delivery Truck Vibration Levels in KoreaKim, Saewhan; Horvath, Laszlo; Lee, Soohyung; Lee, Sangwook (MDPI, 2024-04-12)South Korea has one of the largest e-commerce markets in the world. The last-mile delivery segment of e-commerce often causes critical damage to products in protective packages. Despite the rapid growth of the e-commerce market in Korea, the last-mile distribution environment has not yet been thoroughly investigated. The main aim of this study was to provide an understanding of the vibration levels that were measured from various parcel delivery routes within Seoul, Korea, using common types of parcel delivery trucks. Vibration levels of ten delivery trucks were measured and analyzed in terms of power spectral densities (PSDs) and presented as PSD spectra. The last-mile delivery vehicle vibration levels in Korea were found to be consistently lower (in the 1 to 200 Hz frequency range) than those recommended by international standards and lower than the vibration levels of parcel delivery vehicles in the U.S. and Hungary. The results also revealed that the highest intensity peak of the PSD spectrum for Korea was located in the lower frequency range (1.5 to 2 Hz) compared to the ISTA 3A pickup and delivery test profile (3 to 4 Hz) and the test profile recommended for Hungary (13 to 16 Hz). A smoothed composite spectrum was also provided to support Korean packaging engineers in optimizing their packages by simulating proper last-mile truck delivery vibration levels in lab conditions.
- Realizing a dream: linking sustainable enterprise development with sound forest management – the case for Black Walnut SyrupHammett, A. L. (Tom) (New River Symposium, 2024-04-12)Virginia Tech and Future Generations University have been collaborating on projects in the region that foster sustainable nature-based enterprises. For several years, the focus has been on maple syrup, a product with a deep heritage in the New River Valley and surrounding areas. Recently, we have built on the experience with sugar maple, and have conducted research and outreach with another tree syrup – black walnut. Black walnut is plentiful and well suited to many sites in the region. The tapping process ensures that the tree is not harmed and will continue to provide ecological benefits. Well known in other regions for its timber quality, the species is not well known for producing tree syrup. But black walnut syrup is not well-known but is fetching higher prices than maple syrup and is popular among bakers, especially in the New York City area. The author won first prize for his black walnut syrup at the 2022 New River Valley Fair! Our outreach and research projects have focused on tree syrup and non-timber forest products. Many in the area request assistance to assess the potential for tree saps. Our team has developed demonstration sites and conducted outreach activities with landowners at several sites including Tazewell, Montgomery, and Giles Counties. Research is needed to gather input from landowners, evaluate the potential for sustainable economic development, and incorporate black walnut in forest management plans. We will discuss black walnut syrup’ potential to foster sustainable development, build community resilience, and ensure sustainable land management.
- Reflecting on East Africa: Incorporating Sustainable Development Goals into Curriculum in VirginiaHammett, A. L. (Tom) (2023-11-14)Organized, presented, and moderated; for International Education Week
- Branching Out: Alternative Tree Saps Integrated with AgroforestryHammett, A. L. (Tom) (2023)
- Understory Botanicals and Eatables: A Guide to Educational Resources for Appalachian Agroforestry by the Livelihoods Knowledge Exchange NetworkHammett, A. L. (Tom) (2023)The purpose of this series is to describe particular production systems for small holdings in Appalachian cove forests. In this scenario, we will describe how to use the forest understory to grow forest botanicals for nutrition and health uses, and as a source of income. There are numerous examples of understory plants that can be grown in the region - each of which can contribute to income and nutrition and sustain the landscape. Agroforesters recognize and celebrate the historical legacy these plants represent for residents in the region.
- Agroforestry in Appalachia-Laurel Fork SapsuckersHammett, A. L. (Tom) (2023)
- Making Maple Syrup in VirginiaHammett, A. L. (Tom) (2023-03-14)Invited presentation to the Lifelong Learning Institute.
- Linking Agriculture and Sustainable Natural Resource Management: Opportunities for Social ChangeHammett, A. L. (Tom) (2023-11-13)
- SDGs in East Africa-Centered Education: Lessons from a Fulbright-Hays InstituteCranwell, Lindy; Emmett, Robert; Fitzgerald, Rachel; Hammett, A. L. (Tom) (2023-11)
- Commercial products derived from plants: Maple SyrupHammett, A. L. (Tom) (2023-02-13)An invited lecture to biology students at Radford University.
- East African History, Geography, and Sustainability: Tanzania and KenyaCoffee, Frances; Hammett, A. L. (Tom); Gibson, Lisa (2023-11-30)
- Engaging Students in NTFPs- Opportunities for Experiential LearningHammett, A. L. (Tom); Hindman, Daniel (2023-06-07)