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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.

Recent Submissions

Participant-driven gathering: the ‘un-meeting’ way to engage agricultural producers with the sustainable livelihoods framework (SLF)

Adebayo, Bolanle; Kaufman, Eric K.; Olowoyo, Olamide; Poudel, Sonika; Seibel, Megan M.; Parrella, Jean A.; Spence, Jessica R.; Tyler-Mackey, Crystal; Grove, Ben; Zhu, Stephanie; Gutter, Mike (Taylor & Francis, 2026-06-12)

Sustainable agricultural livelihoods are foundational to achieving sustainable food systems, yet contemporary agricultural actors face interconnected challenges – including climate change, labor constraints, land-use pressures, and policy misalignment – that are insufficiently addressed by earlier livelihood frameworks. This communication paper introduces the 21st-century Sustainable Livelihoods Framework (SLF) as a conceptual lens for understanding agricultural livelihoods, emphasizing the relational dynamics among diverse livelihood actors and the structural processes shaping access, agency, and outcomes. Drawing on data from a participant-driven, participatory convening of agricultural stakeholders (a.k.a. “un-meeting”), this study examines how such methods can surface shared priorities and map livelihood dynamics across heterogeneous agricultural contexts. Qualitative analysis of 313 participant notecards, observers’ field notes, and summit planning documents revealed themes strongly aligned with components of the 21st-century SLF, including environmental dynamics, assets, relational power, and pathways to livelihood sustainability. Findings demonstrate that unconventional meetings like this provide an effective participatory mechanism for bringing together producers, Extension professionals, researchers, and industry actors to deliberate challenges, identify opportunities, and align priorities across diverse agricultural livelihoods. The results further highlight the central role of the Cooperative Extension system as a forerunner in facilitating grassroots producer engagement, strengthening relational connections among stakeholders, and enabling the transformation of structures and processes – such as policy development, research agendas, workforce preparation, and education – necessary for sustainable agricultural livelihoods. Overall, this study contributes empirically and conceptually by illustrating how participatory un-meetings can operationalize the 21st-century SLF in practice and by reinforcing the importance of Extension-led, bottom-up approaches to advancing sustainable agricultural livelihoods in support of sustainable food systems.

Design and Characterization of Cold-Spot-Free Interconnects for Modular Micro Gas Chromatography Enabling C₃₀ Elution

Dewanjee, Suman (Virginia Tech, 2026-04-24)

Semi-volatile organic compounds (SVOCs) such as long-chain n-alkanes, polycyclic aromatic hydrocarbons (PAHs), phthalates, and pesticides are widespread environmental pollutants. They possess low vapor pressures and boiling points typically exceeding 300 oC. These compounds partition across air, soil, water, and particulate matter, posing persistent risks to human health and ecosystems. The atmosphere spans nearly 15 orders of magnitude in organic vapor pressure, underscoring the need for analytical platforms capable of resolving the full volatility range from volatile organic compounds (VOCs) to intermediate- and semi-volatile species (I/SVOCs). Gas chromatography (GC) combined with flame ionization detection (FID) or mass spectrometry (MS) continues to be the reference method for SVOC analysis. However, conventional benchtop systems are bulky, power-intensive, and unsuitable for field-deployable or real-time monitoring. Microfabricated gas chromatography (µGC) has emerged as a compelling miniaturized alternative, leveraging microelectromechanical systems (MEMS) fabrication to integrate micropreconcentrators (µPC), microseparation columns (µSC), and detectors within compact, low-power platforms. Modern μGC platforms separate complex mixtures in seconds to minutes at part-per-billion levels and support applications in environmental monitoring, industrial control, medical diagnostics, and security screening. Despite these improvements, the majority of μGC instruments are still tuned for highly volatile analytes; many portable versions cannot handle semi-volatile species above a certain threshold. Higher-boiling compounds tend to broaden dramatically or disappear because they condense or adsorb on cooler surfaces. This limitation is especially pronounced in modular µGC architectures, where discrete MEMS components such as µPC, µSC, and detectors are physically interconnected through transfer lines and chip-to-chip junctions. These inter-device interfaces are inherently susceptible to heat loss via conduction into mounting structures and convection to the ambient environment, producing non-isothermal regions known as cold spots. Even over distances as short as a few millimeters, cold spots induce analyte condensation, severe peak broadening, and irreversible sample loss for high-boiling SVOCs, effectively imposing a hard upper boiling-point limit on modular µGC platforms. Conventional remedies like bulky convection ovens or fully monolithic device ii integration address cold-spot formation at the expense of increased volume, power consumption, and fabrication complexity, undermining the core advantages of miniaturized chromatography. The study overcomes these constraints by developing and experimentally validating a cold-spot-free interconnect approach for modular μGC systems. The strategy builds on the Fluidic and Electrical Modular Interfacing (FEMI-GC) platform previously introduced by the VTMEMS group. Although FEMI GC provided swappable, gas-tight, low-dead-volume connections, it was limited to analytes lighter than C₁₂ because the junctions themselves acted as unheated cold spots. This present work addresses these thermal management challenges by developing and validating a cold-spot-free interconnect strategy within the FEMI-GC. Actively heated transfer line was integrated between a MEMS µPC and a 2-meter ionic-liquid-coated MEMS µSC. Macor® machinable glass-ceramic spacers were employed at the junctions to provide thermal isolation, protect adjacent 3D-printed polymeric components, ensure precise alignment, and maintain gas-tight sealing. A dual-modality thermal characterization approach combining two-dimensional finite element analysis (FEA) in COMSOL Multiphysics® and high-resolution infrared (IR) micro-thermography was used to guide and validate the design. FEA simulations revealed severe axial temperature gradients, with the center of the unheated 16 mm transfer line dropping to ~43 oC while adjacent components exceeded 200 oC. Active heating successfully eliminated cold spots, establishing a near-isothermal analyte flow path at the micropreconcentrator, transfer line, and separation column. Chromatographic performance was evaluated using C7–C30 n-alkane standards, with the µPC operated at 275 oC in heated pass-through (bypass) mode. Due to the lack of preconcentration and focusing for the lightest analytes, C7–C12 peaks appeared broad in both configurations. In the unheated setup, only C13–C19 showed acceptable peak shapes, while compounds ≥C20 suffered severe broadening and near complete loss. With active transfer-line heating, the full C13–C30 series was recovered with sharp, symmetric, and well-resolved peaks, that were undetectable without heating. The system demonstrated excellent stability across five replicate injections (40 ng each), with retention time RSDs of 0.11–0.14%, peak area RSDs of 6.4–14.8% (n=5), and asymmetry factors averaging 1.63 for C20–C30. No carryover was detected after high-mass injections of C26 (68 ng) and C28 (96 ng).

Analyzing an Avian Influenza model with probable human to human transmission

Lang, Casey T. (Virginia Tech, 2026-04-22)

Understanding the disease dynamics of avian influenza is crucial for proper outbreak response. In this study, we develop a model for avian influenza with probable human to human transmission, including a bird handler class and the concentration of the virus in the environment. We assess virus dynamics and behavior at equilibrium solutions. Additionally, we perform a simulation for a potential real world outbreak of the disease using population data from Dawes County, Nebraska, and we perform sensitivity analysis for parameters in the model, calculating Partial Rank Correlation Coefficient values as well as elasticities. We also perform identifiability analysis on the model. We find that an outbreak of such a mutation could lead to a large percentage of the human population becoming infected, and in such an outbreak, determining the true parameters of the corresponding model may prove to be difficult, with only the true value of the death rate of the mutated disease being obtainable given that prevalence data and data for the populations of each susceptible class is collected and the true values are known for every parameter in the model not related to the mutation.

Satellite Geodetic Constraints on Managed Aquifer Recharge Effectiveness for Subsidence Hazard Mitigation

Onyike, Florence (Virginia Tech, 2026-03-23)

Accelerating groundwater depletion driven by rising water demand and climate variability poses mounting challenges to global water security. As aquifers are overexploited and compacted, widespread land subsidence threatens communities, infrastructure stability, and ecosystem sustainability. Managed Aquifer Recharge (MAR), by artificially replenishing groundwater storage and alleviating effective stress within aquifer systems, offers a promising pathway to restore balance and enhance long-term resilience. However, empirical evidence for MAR's effectiveness in mitigating subsidence across diverse geological and climatic settings remains limited. Here, we present a multi-continental synthesis of MAR performance for land subsidence mitigation at 12 high-volume sites across 10 countries, based on satellite radar observations. Average vertical land motion (VLM) rates varied across MAR sites, ranging from +4.0 mm/year uplift (Orange County, USA) to -2.4 mm/year subsidence (El Carracillo, Spain). Four sites exhibited net uplift, three showed mixed deformation responses, and five continued to experience net subsidence despite ongoing recharge operations. Spatio-temporal analysis reveals moderate to strong correlations (r = 0.5–0.9) between land elevation changes and variations in groundwater levels, drought severity, and regional terrestrial water storage variations. We distinguish aquifer compaction trends from elastic loading signals using independent component analysis (ICA), highlighting that both local aquifer pressurization and broader basin-scale hydrological processes influence MAR effectiveness. We show that MAR effectiveness is governed by a hierarchy of controls, where aquifer architecture constrains the potential for recovery, hydroclimatic forcing sets regional boundary conditions, and operational intensity modulates local response. Sites with responsive geological conditions achieved measurable uplift even under water stress, while unfavorable geology limited effectiveness regardless of recharge intensity. These findings provide empirical evidence for the strategic implementation of MAR and highlight the importance of integrated watershed-scale management under intensifying climate pressures and water demands.

If Heaven Had a Color

Raveen, Ifreen (Virginia Tech, 2026-06-17)

If Heaven Had a Color is a multigenerational novel following a family across eight decades, from the 1920s to the 1990s. Set in a time where Kashmir moves through various forms of oppression — the begar system, partition, and insurgency — the novel traces the impact of prolonged conflict on the people of the valley through the experience of one family. It is a novel about the women who remained behind, who had to navigate the war from within the walls of their homes, who had to do fundamental things like go to college even as the conflict rewrote the world around them. If Heaven Had a Color also explores how ecological trauma mirrors human trauma. For a place like Kashmir where identity is inseparable from its springs, mountains, and trees, conflict does not only wound people. It wounds the land. To lose your basic rights is also to lose access to the places that have always held you: springs barricaded, mountains occupied, forests closed off by army camps. The land you grew up on, the nag your grandmother prayed beside, the hill you walked to as a child are seized, fenced, forbidden. In Kashmir, the occupation of land and the occupation of a people are the same violence. The folklores passed down through generations reflects the rich and layered culture of Kashmir. In times of war, these stories also become acts of preservation of an identity and history that the occupation seeks to erase.

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