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The Design and Characterization of a Prototype Wide-Size Range Aerodynamic Focusing Lens
No full textAerodynamic focusing lenses (AFLs) are used to generate highly collimated particle beams by passing particle-laden air through a series of axisymmetric contractions. The most common use for AFLs is as inlets to aerosol mass spectrometers, which allow for the in-situ and real time analysis of aerosols to understand their physical and chemical properties. However, available AFLs focus only a small fraction of particle sizes that affect human and environmental health. Currently, multiple lens systems are needed to study the entire aerosol size range of interest, which is both cost and time prohibitive. We address this challenge by designing a prototype wide-size range AFL (P-WAFL) that attempts to focus 10 nm – 10 μm particles. Computational fluid dynamic (CFD) simulations were conducted to optimize the design, and the performance of this new AFL has been characterized both in our laboratory and at the Pacific Northwest National Laboratory (PNNL). It was found that the P-WAFL had an effective focusing range of 30 nm – 700 nm. While the P-WAFL fails to successfully focus more than one order of magnitude of particle sizes, its effective focusing range is nearly double that of the standard AFL (40–400 nm) used in the miniSPLAT instrument at Pacific Northwest National Laboratory (Zelenyuk et al., 2015). Overall, the work presented in this thesis provides a foundation for the future development of AFL systems with enhanced particle transmission efficiency over a broader range of particle sizes
Shock Waves in Gas and Plasma in Strong Magnetic Fields
No full textShock waves in magnetized plasma are central to particle acceleration, high-energyradiation, and energy transport in astrophysical systems. However, direct measurements
in the MG field regime relevant to white dwarf accretions, cataclysmic variables,
and supernova remnants remain under tested. In this dissertation I develop an experimental
platform combining a 50 TW ultrafast laser and a 1-MA pulsed-power generator
to produce and diagnose laser-driven shocks propagating through gas and plasma in
externally applied megagauss magnetic fields, a strong field regime not tested before.
Experiments were performed at the Nevada Terawatt Facility(NTF). The platform
uses the approximately 30 J, 0.35 ps–0.8 ns, 1056 nm Leopard laser focused onto
1–2.5 mm Cu rod loads positioned inside the Zebra pulsed-power vacuum chamber. A
plasma piston produced by laser ablation drives a shock wave into an ambient hydrogen
or nitrogen gas. Zebra drives 0.7–1.5 MA of current, generating azimuthal magnetic
fields up to ≥ 100 T at millimeter distances from the rod surface. Magnetic fields were
directly measured using two-color Faraday rotation with TGG crystal probes.
Multi-frame optical diagnostics were developed and integrated into the Zebra chamber.
This includes 266 nm interferometry, 532 nm shadowgraphy, schlieren imaging,
4-frame side-on imaging perpendicular to the rod, and vertical imaging parallel to the
rod axis. These diagnostics enable time-resolved measurement of shock front position,
curvature, density gradients, and velocity anisotropy, with temporal resolution on the
order of several nanoseconds and μm spatial resolution. Detailed gas-jet density profiles
between 1018 and 1019 cm−3 were calculated using Abel inversion algorithms.
In shots without applied magnetic field, the shock expands quasi-spherically with
measured front velocities in the range 500–1600 km/s. In the presence of MG magnetic
fields, however, the dynamics change qualitatively. The shock front becomes
anisotropic: radial expansion (perpendicular to B) is suppressed, while azimuthal expansion
(parallel to B) remains significantly less affected. We additionally observe a
high-speed azimuthal spread of plasma consistent with magnetic channeling of charged
particles along field lines. In hydrogen, we directly measure an ionization wave ahead
of the shock creating a cylindrical plasma channel simultaneously providing both gas
and plasma shock medium.
Simulations using 1-D Lagrangian HELIOS and 2-D HYDRA codes support the
experimental interpretation and show that magnetic pressure B2/2μ0 modifies the
effective shock jump conditions, when β ≤ 1. It’s found with the tested experimental
parameters the shock velcoity anisotropy scales with the magnetic field strength. The
observed change to the shock symmetry can be explained with the inclusion of the
magnetic pressure.
This dissertation therefore presents laboratory measurements of laser-driven shocks
in gas in MG magnetic fields, providing optical measurements of magnetic-field-modified
shock geometry and velocity, and establishes a platform that can now access the field
regime of intermediate polars. These results demonstrate that the transition from
collisional to magnetically mediated shock structure can be studied in a controlled
laboratory environment, and that laboratory plasma platforms can reach the magnetization
needed to study astrophysical collisionless shock phenomena at previously unexplored field strengths
Pedestrian Safety and Level of Service at Uncontrolled Crosswalks - Advanced Data to Enhance Evaluations
No full textPedestrian safety and mobility assessment at uncontrolled crossings is often hindered by the limitations of crash-based evaluation and the inconsistent quality of high-resolution all-traffic trajectory data collected from emerging sensing technologies. As agencies increasingly rely on behavioral and surrogate measures to diagnose risk, the need for reliable, continuous pedestrian–vehicle movement data becomes critical. This dissertation develops a unified methodology structured around two major components. The first component introduces a robust trajectory data enhancement framework that addresses noise, temporal discontinuities, and structural errors inherent in raw multimodal trajectories. The proposed post-processing pipeline integrates trend-based smoothing, iterative outlier detection, and gap reconstruction to produce accurate and behaviorally consistent movement traces. The second component establishes an automated pedestrian–vehicle interaction analysis framework capable of extracting yielding behavior, compliance patterns, and pedestrian service performance directly from enhanced trajectories. This framework formalizes interaction zones, temporal alignment rules, and decision logic to ensure consistent and reproducible behavior classification. To demonstrate the applicability and scalability of the methodology, three case studies were conducted using multimodal trajectory datasets collected along a commercial corridor in midtown Reno, Nevada. These studies evaluate safety and operational performance under varying geometric designs and local traffic conditions. Results show that trajectory enhancement substantially improves data quality, enabling fine-grained, data-driven assessment of pedestrian–vehicle interactions. The integrated methodology provides transportation agencies with a rigorous analytical foundation for proactive safety evaluation and evidence-based design decisions at uncontrolled crossing
The future of fishing in Southeast Asia's largest lake: Quantifying fishing effort and harvest in Cambodia’s Tonle Sap
No full textDespite their importance for food security and livelihoods, many inland fisheries lack the spatiotemporal catch and effort data required for sustainable management. The Lower Mekong Basin supports one of the world’s most productive and biodiverse inland fisheries, but contemporary data on fishing effort and catch are largely absent. This study uses high-resolution (<80 cm) satellite imagery and unmanned aircraft systems (UAS) to map, measure, and standardize fishing-effort metrics for large, stationary arrow-shaped traps, one for the most abundant fishing gear in Cambodia’s Tonle Sap Lake. We also develop a generalized framework for using aerial technologies to assess fishing effort in data-limited, subsistence fisheries. Combining seasonal arrow trap counts from fisher reports and remote sensing with species-specific biomass data, we analyze spatiotemporal patterns in catch and effort and provide the first estimates of annual fish harvest for the Siem Reap arrow trap fishery since 1997-1998. Using satellite imagery covering 50 km of shoreline in Siem Reap Province, we mapped 1,050 traps in 2021, 1,288 in 2022, and 737 in 2023. Mean trap length was 178 ± 103 m (range: 10–700 m). Arrow trap netting density averaged 1,550 ± 1,539 m/km² (range: 1–7,290 m/km²), indicating significant spatial variation, with highest effort in Pouk district and lowest in Bakong district (p = 1.2×10⁻5). UAS imagery provided fine-scale seasonal data in 2023 and filled gaps where satellite coverage or contrast was limited. Aerial survey results corresponded with survey data, confirming reliability of remote sensing approaches while also revealing localized challenges with illegal, unreported, and unregulated fishing. These methods form a reproducible monitoring framework that assesses trap abundance, spatial distribution, and compliance with existing fishing regulations. This framework can be applied to support scalable, remote assessments of fishing effort and track long-term trends in fishing pressure in Cambodia and other marine and inland fisheries worldwide. By combining seasonal arrow trap counts from remote sensing and fisher reports with species-specific biomass data, we also analyzed spatiotemporal patterns in catch and effort. Arrow trap fishing effort and harvest in Siem Reap Province have increased approximately threefold since the last published assessment, likely driven by a shift from more vulnerable large-bodied species to small-bodied taxa and by changes in fisheries governance. More than 1,200 traps operated in 2023, producing approximately 3.0 × 10⁶ kg of harvest, compared to 327 traps and just over 920,000 kg reported in 1997-1998. Arrow trap catch was dominated by ten species, which together accounted for 51% of the total biomass. Analysis revealed strong seasonal and spatial variation in catch-per-unit-effort (CPUE) and species assemblage. Species assemblage differed significantly among fishing districts and seasons, with northern districts dominated by floodplain-resident species and the southernmost district characterized by species adapted to open-water and riverine habitats. Species richness and diversity were highest after peak inundation in December, whereas low- and rising-water periods supported fewer species. CPUE was highly variable (mean = 6.85 ± 9.23 kg/trap-day) and differed significantly by season and district (p = 0.001), peaking in March and December and declining in June and September, except in the southernmost district where catches remained consistently high. These results provide a contemporary baseline for evaluating long-term trends in catch, yield, community composition, and fishing pressure in the Tonle Sap Lake. More broadly, this study highlights the potential of remote-sensing approaches to enhance monitoring of illegal, unreported, and unregulated fishing and support sustainable fisheries management worldwide
Slit2, a Multifaceted Guidance Cue, Essential for Establishing Proper Sympathetic Innervation Architecture
No full textSympathetic innervation is essential for adipose tissue function, yet the developmental cues thatshape these neural circuits remain undefined. Here, we identify SLIT2 as a critical regulator of
sympathetic patterning in embryonic adipose tissue and demonstrate that its proteolytic
processing is required to balance axon restriction and branching. Loss of Slit2 (Slit2−/−) caused
excessive sympathetic arborization, whereas cleavage-resistant Slit2 (Slit2ΔTLS/−) produced
diminished branching and expanded gaps in innervation. Robo1/2 knockouts phenocopied Slit2
loss, establishing that Slit2 signals through ROBO receptors, while Tll1 deficiency mirrored the
Slit2ΔTLS phenotype, confirming that Slit2 proteolysis is required in vivo. Using PDGFRα-
directed deletion, we identify stromal precursors and adipocytes as a key tissue source of Slit2.
Finally, SCG neuron cultures reveal fragment-specific effects of SLIT2-FL, SLIT2-N, and
SLIT2-C on neurite morphology. Together, these findings define Slit2 cleavage as a mechanism
that sculpts sympathetic innervation of adipose tissue and suggest that altered Slit2 signaling may
influence long-term adipose metabolic function
AIEI Newsletter, January 2026
No full textFederal Highway AdministrationUnited States Department of Transportatio
Traditional Marine Management Systems in Northwest California: The Archaeology and Implications of Indigenous Stewardship Practices for Modern Marine Conservation and Restoration
No full textTraditional Marine Management Systems (TMMSs) represent deeply intertwined frameworks of ecological stewardship and cultural heritage rooted in Indigenous knowledge systems, socio-cultural practices, and socio-economic relationships within marine ecosystems. These systems have endured over generations through Traditional Ecological Knowledge tied to cultural landscapes, involving integrated strategies of resource procurement and management designed to enhance and sustain the abundance, diversity, and accessibility of marine resources. Despite California being a major focus of archaeological research over the past century – with over 12,000 years of documented coastal occupation – scholars have rarely examined how Indigenous societies have actively shaped marine ecosystems. Practices such as targeted harvesting, habitat enhancement, tenure systems, and resource governance remain largely underexplored, even with ethnographic and archaeological examples around the Pacific Coast.This dissertation explores concepts of TMMSs along California’s Lost Coast through the lens of Niche Construction Theory, by investigating specific settlement-subsistence strategies, socio-economic relationships, and marine stewardship practices that sustained or enhanced coastal productivity, promoting cultural resilience during periods of greater seasonal variability and environmental change in the Late Holocene (after 4200 cal BP). I employ a multi-scalar, interdisciplinary approach that integrates archaeological surveys, material studies, faunal analysis, remote sensing, ecological modeling, and radiocarbon dating of coastal sites.
Early Middle Period (3500-1500 cal BP) settlements were located near productive marine ecosystems, supporting diversified subsistence strategies. After 1500 cal BP, more permanent villages and a few logistical camps developed along the Lost Coast. Coastal populations increased substantially after 700 cal BP, marked by an expansion of permanent villages, logistical campsites, and food processing stations. These developments formed core residential areas near previously located productive marine ecosystems and extended into new locations along the coast. Subsistence strategies broadly focused on diversified diets with complimentary, multi-harvesting of shellfish and fish from nearshore intertidal environments, but intensive harvesting of certain species varied regionally with specialized tool kits, likely informed by cultural traditions relating to local environments. Since the earliest occupation of the Lost Coast, long-distance trade across northern California and the Great Basin was widespread and intensified after 700 cal BP with the rise of specialized craft production of shell beads and ornaments. By contextualizing these patterns within broader socio-economic networks, this research highlights the enduring social, cultural, and ecological legacies of maritime economies.
Two case studies explicitly test how Indigenous communities shaped nearshore environments over the past 2,700 years. Mussel size data from over 9,000 shells across eight archaeological sites, combined with harvesting models and ecological simulations, reveal selective, rotational harvesting that sustained and enhanced mussel populations for millennia. Isotopic analysis suggests seasonal shellfish harvesting primarily during late spring, early summer, and possibly early fall. UAV-based surveys and ecological mapping near a major ancestral village of Sεcōdañ document maricultural innovations such as abalone gardens and stone fish traps, which increased intertidal productivity and supported diverse lifeways. These findings demonstrate that culturally embedded strategies and traditional tenure systems help sustain ecosystems while supporting diverse subsistence and maritime economies. They offer valuable models for contemporary marine conservation and restoration, while supporting the cultural revitalization of Indigenous stewardship practices and foodways
Capturing Elusive Metrics in Economics
No full textThis dissertation presents three chapters that address distinct economic challenges requiring novel data sources and methodologies. Chapter 1 introduces a computational text analysis technique for historical economic texts using natural language processing. Chapter 2 employs an experimental design to examine how gendered impartial spectators evaluate credit-stealing behavior through the lens of bounded ethicality. Chapter 3 evaluates the impact of wind generation on Türkiye’s electricity system and its relationship to the country’s energy security strategy. Chapter 1 analyzes the intellectual journey of John Stuart Mill between two representative works, On Liberty and Socialism. Using pre-trained transformer models, the study applies thematic classification and semantic similarity analysis to interpret Mill's views on libertarianism, laissez-faire, socialism, and other economic concepts. These results are compared to existing scholarly debates over Mill's ideological consistency. Findings indicate that Mill maintained a consistent and positive view toward social welfare in both works and, surprisingly, a consistently negative view of laissez-faire. These results both support and challenge existing scholarly interpretations of Mill's ideology. Chapter 2 employs a quasi-spectator framework with incentivized attention to evaluate credit stealing in the workplace from a gendered impartial spectator perspective. Respondents reviewed workplace vignettes and received monetary incentives for correctly recalling key details, ensuring awareness of the scenarios. Results indicate that while male and female respondents agreed on what occurred and how credit should be allocated, they showed different assessments of the ethicality and workplace consequences of those actions. These findings are interpreted through the lens of bounded ethicality. Chapter 3 finds that wind generation in Türkiye primarily displaces natural gas, hydropower, and, to a lesser extent, imported coal. Despite uniform renewable subsidies, there is significant heterogeneity in the displacement impacts of individual wind farms across these fuel types. Given Türkiye’s large hydropower capacity and its ability to effectively store renewable energy, secondary hydropower effects were calculated and show additional displacement of natural gas. These findings align with Türkiye’s current energy security policy to reduce reliance on import-dependent fuels such as natural gas and imported coal and to prioritize renewable energy
From Pulses to Pathways: Unveiling Molecular Motion and Energy Landscapes with 2D IR Spectroscopy
No full textTwo-dimensional infrared (2D IR) spectroscopy is a powerful technique for probing vibrational dynamics, including energy transfer, molecular interactions, and hydration dynamics, with ultrafast temporal resolution. By capturing spectral diffusion, vibrational coupling, and energy dissipation mechanisms, 2D IR provides direct insights into how molecular environments and structural modifications influence energy transport on femtosecond to picosecond timescales. This dissertation investigates the mechanisms governing vibrational energy redistribution and hydration dynamics in molecular systems using 2D IR spectroscopy coupled with vibrational probe methodologies. The role of Fermi resonance, i.e. strong anharmonic coupling, in directing vibrational thermal energy flow is explored using azido and cyano vibrational probes as reporters. Structural modifications, such as π-conjugation, steric constraints, and vibrational bottlenecks, were found to either facilitate or suppress energy transport. Heavy atom substitution, i.e. isotopic labeling, act as vibrational inhibitors, disrupting anharmonic pathways and enabling through-space dipole-dipole interactions to dominate. Additionally, my work examines the role of solvent viscosity and local solvation dynamics on spectral diffusion, revealing that frequency fluctuations of vibrational probes are dictated more by hydration shell structure than bulk solvent properties. Through a combination of experimental 2D IR measurements and molecular dynamics simulations, my study shows that second-shell solvent reorganization plays a dominant role in vibrational dephasing. By leveraging 2D IR spectroscopy, this dissertation provides new insights into the regulation of vibrational energy transport, solvent-mediated coupling, and tunable molecular interactions. These insights are further applied to probe catalytic behavior in Cu–peptide complexes, demonstrating how vibrational spectroscopy can guide the design of molecular systems with improved catalytic selectivity and reduced aggregation. These findings have broad implications for biomolecular spectroscopy, materials science, and the design of molecular systems with controlled energy flow
Bringing Assent into Behavior Analysis: Qualitative, Functional, and Meaningful
No full textApplied behavior analytic (ABA) services such as Early Intensive Behavioral Interventions (EIBI) have been shown to be an evidence-based approach for supporting autistic individuals. Autistic advocates have identified that individuals who have received applied behavior analytic services have experienced traumatic experiences including an over-emphasis on compliance, diminished autonomy, and long-term challenges in self-advocacy (Anderson, 2022; Sandoval-Norton et al., 2019; Wilkenfeld & McCarthy, 2020). In response to these concerns and the gap in literature, the implementation of assent frameworks (Breaux & Smith, 2023; Flowers & Dawes, 2023; Morris et al., 2021, Morris et al., 2024) within clinical settings has been emphasized in behavior analysis. We embedded a functional behavior assessment process into current ABA services provided at a community organization to evaluate the feasibility of implementation of an assent framework and to evaluate effects the framework may have upon service delivery and client progress. Our data suggest that these procedures are feasible to add to current clinical procedures to increase adherence to child assent without negatively affecting the productivity of each session or client progress