VTechWorks
VTechWorks provides global access to Virginia Tech scholarship, including journal articles, books, theses, dissertations, conference papers, slide presentations, technical reports, working papers, administrative documents, videos, images, and more by faculty, students, and staff. Faculty can deposit items to VTechWorks from Elements, including journal articles covered by the University open access policy. Email vtechworks@vt.edu for help.
Open Access Policy
Virginia Tech's open access policy enables researchers to deposit the accepted version of scholarly articles with no embargo.
Theses and Dissertations
Virginia Tech was first in the world to require ETDs in 1997, and continues to add scans of older theses and dissertations.
Open Textbooks
More than 50 freely available and openly licensed textbooks are among our most downloaded items.
Communities in VTechWorks
Select a community to browse its collections.
Recent Submissions
Conserving Water in Agricultural and Forestry Industries: Methods for Improving Water Use Efficiency
Thomas, Kaede; Friefeld, Julia; Thesmar, Cooper; Pondugula, Aniketh; Miah, Mohammed (Virginia Governor's School for Agriculture, 2025-07-19)
This paper aims to explore three common water conservation techniques used to conserve water and increase water use efficiency in the agriculture and forestry industries. Global water scarcity has increased substantially in recent decades, and the agricultural industry is the greatest consumer of freshwater resources throughout the world. In the United States specifically, the agricultural industry, along with forestry, is responsible for roughly 40% of national water stress. Because of this, there have been significant efforts to improve water use efficiency within the industry; improved irrigation methods, exploration of different water collection methods, and the development of water-conserving landscape designs are just some of the different techniques. These practices are being further researched in conjunction with the United Nations’ Sustainable Development Goal Six, to ensure the availability and sustainable management of water and sanitation for all, and Goal Twelve, to ensure responsible consumption and production patterns. The specific practices explored in this paper are rainwater harvesting, the creation of riparian buffers, and drip irrigation. Using these techniques, this paper aims to answer the question: What are the benefits and drawbacks of three different techniques of improving water efficiency in agriculture, and how are the techniques best applied? This paper strives to provide background on each practice and discuss the strengths and limitations of each one. This will help provide information on which types of practices should be used in specific situations. The practices vary in a number of ways, from how the systems are designed to where they work best, but there is a significant amount of overlap when it comes to the overarching goals and the problems they face. As such, an overview of each is provided along with the benefits and challenges of their utilization. This is followed by a comparative analysis of all the methods discussed and in what situations each would be best utilized.
Agriculture and Water Management: Strategies for Precision On-Farm Water Management
Chee, John Y.; Korunka, Aurora W.; Tagge, Kent W.; Woo, Amy H. (Virginia Governor's School for Agriculture, 2025-07-19)
Water is a foundational component of supporting ecosystems, the climate, and all living organisms. Fresh water drives all global systems, but most specifically agriculture and livestock. Agricultural industries’ consumption of water accounts for 70% of all water that is consumed annually. Of the 2 quadrillion gallons of water that are used, upwards of 40% is lost due to water inefficiency and waste. Such losses contribute to rises in poverty levels, food insecurity, GDP declines by as much as 6%, and water shortages. With the global population expected to reach almost 10 billion by 2050, there is a clear need to optimize agricultural production by enhancing water use efficiency. These alarming statistics emphasize the need to transition to more sustainable water management systems. The objective of this review is to identify and evaluate three precision on-farm water management strategies to improve water use efficiency and reduce waste in agriculture. In doing so, this research aims to support sustainable agricultural practices, meet USDA AFRI (Agriculture and Food Research Initiative) priority area “Agriculture Systems and Technology”, and reach UN Sustainability Goal 6 (Clean Water and Sanitation), Goal 9 (Industry, Innovation, and Infrastructure), and Goal 12 (Responsible Consumption and Production). In this paper, the precision irrigation techniques, drip irrigation and variable-rate irrigation (VRI) systems will be discussed. Next, drought-resistant crops (DRCs) and their benefits to farmers when relation to waste prevention will be investigated. Lastly, the study will explore modular floating covers as a form of dam evaporation control. Although these methods of preserving water and increasing water efficiency are extremely beneficial while already having been implemented for on-farm systems, there is room for further technological improvements.
Age-Dependent Determinants of Blood-Derived Monocytes Influence Neuroinflammatory Milieu at the TBI Injury Site
Willison, Andrew Wayne (Virginia Tech, 2025-11-25)
Traumatic brain injury is a leading cause of neurologic injury. Excess and prolonged neuroinflammation post-injury negatively influences recovery outcomes. Blood-derived monocytes are capable of performing efferocytosis, the immunologically silent engulfment of cellular debris, which is critical for removing hazardous cellular corpses and concurrently resolving inflammation. Age-at-injury profoundly effects TBI recovery outcomes also. The phenotypic and functional plasticity of blood-derived monocytes (BDMs), as well as prior studies relating age and BDM activity, place BDMs at the crossroads these two advantageous elements, making them a promising potential therapeutic option for TBI. In this thesis, we assess how juvenile and adult BDMs differ in their response to TBI, hypothesizing that juvenile BDMs will take greater action to discourage neuroinflammation and promote tissue recovery. We performed passive injections of juvenile BDMs into CCI injured adult mice. We immunohistochemically stained the tissue for cell type and polarization state markers, then visualized the injured cortex and hippocampus with fluorescence microcopy probes and 3D reconstruction of confocal images. We quantified the lesion volume, IgG deposition and the infiltration, polarization, engulfment activity, distribution, and morphology of BDMs and resident mononuclear phagocytes during the acute phase of injury. We also looked at the population and polarization of resident mononuclear phagocytes during the chronic phase of TBI. We found an overall reduction in tissue damage in juvenile injected mice, and the injected BDMs acted in a manner that suggests the resolution of harmful inflammation after TBI.
The effects of complex I deficiency on neurogenesis and white matter development in a mouse model of Leigh Syndrome (LS)
Biswas, Sahitya Ranjan (Virginia Tech, 2025-11-25)
Leigh syndrome (LS) is one of the most prevalent inherited mitochondrial disorders in pediatric population, typically presenting in early childhood with psychomotor regression and progressive neurological decline. Current understanding suggests that pathogenic variants affecting mitochondrial respiratory-chain complexes impair oxidative phosphorylation (OXPHOS), leading to bioenergetic failure in vulnerable brain regions resulting in the characteristic bilateral, symmetric deep gray matter lesions observed on MRI. While this neuron-centric perspective helps explain regional vulnerability in LS, it overlooks the substantial mitochondrial demand of neural stem/progenitor cells (NSCs), which generate the majority of the brain cells during the embryonic and early postnatal periods. However, the in vivo consequences of sustained mitochondrial dysfunction during early neurogenesis remain poorly characterized. We leveraged the NDUFS4 knockout (KO) mouse, a well-established model of Complex I (CI) deficiency that recapitulates key clinical and neuropathological features of LS, to test whether sustained CI loss during early development disrupts NSC proliferation and lineage progression and secondarily impairs white matter maturation. Gross neuroanatomical analysis revealed reduced brain weight and decreased hemispheric width. Immunohistochemistry showed an early reduction at postnatal day 14 (P14) in NSC and neuroblast populations within the SVZ, with the neurogenic defect progressing at later timepoints to impaired lineage advancement. To resolve cell type–specific effects of CI deficiency, single-cell RNA sequencing (scRNA-seq) was conducted on the SVZ, which revealed a proliferation deficit in NSCs and intermediate progenitors. This finding was independently validated using neurosphere assays. Transcriptional programs and pathways linked to neurogenesis and oligodendrogenesis were significantly downregulated in KO neural progenitors. Although abundance of oligodendrocyte progenitors in the SVZ was not significantly altered, early and late myelin gene/protein expression was reduced, accompanied by decreased corpus callosum thickness. Together, these early neurodevelopmental defects in neurogenesis and callosal growth offer a potential mechanistic explanation for the developmental delays observed in LS. This work encourages future research into neurogenesis in other primary mitochondrial disorders and neurodegenerative disorders, especially those where developmental delays are a key feature.
Process-morphology-property Relationships in Strut-like Poly(ether ether ketone) Aerogels Prepared through Thermally Induced Phase Separation
Spiering, Glenn Allen (Virginia Tech, 2025-11-25)
Poly(ether ether ketone) (PEEK) aerogels resulting from gelation in 1,3-diphenyl acetone (DPA) were prepared for the first time. The phase separation mechanism was determined to be solid-liquid phase separation which resulted in the formation of aerogels consisting of crystalline axialites. These axialites formed a strut-like network that had superior compressive properties compared to the globular aerogels previous prepared from the gelation of PEEK in 4-chlorophenol and dichloroacetic acid. It was also found that strut-like PEEK or poly(phenylene sulfide) (PPS) aerogels prepared from gelation in DPA were mechanically robust such that they could resist the forces imposed on the gel during drying. Monolithic strut-like PEEK or PPS aerogels were prepared with vacuum-drying, freeze-drying, and supercritical CO2 extraction with minimal shrinkage and deformation. The weaker globular PEEK aerogel morphologies suffered from considerable shrinkage due to capillary forces or ice crystal growth induced on vacuum-drying or freeze-drying, respectively. Determining the gelation mechanism of PEEK in DPA allowed for effective manipulation of the processing parameters. It was found that changing the gelation temperature improved the mechanical properties of PEEK aerogels. Dissolution temperature can also be lowered to improve the nucleation density of PEEK aerogels.