UTSA Runner Research Press (Univ. of Texas at San Antonio)
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Stabilization of a Compression Ramp-Induced Shock-Wave/Boundary-Layer Interaction with a Phononic Metamaterial at Mach 7.2
Full text linkThe unsteady nature of shock-wave/boundary-layer interactions (SWBLIs) impose dynamic loading detrimental to flight vehicles in hypersonic flight. Phononic metamaterials (PMs) are materials with frequency-canceling capabilities that have been shown through experiments at UTSA to stabilize cylinder-induced SWBLIs [1]. To observe the PM’s performance on an interaction with potentially more outboard flow separation, a bilayer PM was placed underneath the centerline shock foot of a wall-to-wall compression ramp SWBLI in Mach 7.2 flow. Conventional Z-type schlieren, and surface pressure measurements were taken to study the PM’s band gap (364 - 900 Hz) attenuation performance on the interaction unsteadiness.
Spectral proper orthogonal decomposition (SPOD) of the snapshots was performed to pull SWBLI spatial modes with spectral content. The most dominant mode showed an average attenuation of 11% across the band gap with a 36% peak for the PM test. A Kulite pressure transducer placed centerline, 5.53 upstream of the ramp’s leading edge, captured pressure oscillations upstream of the centerline separation shock and showed an average attenuation of 70% across the band gap for the PM configuration. The difference in attenuation between both analyses is most likely attributed to the fully path-wise integrated nature of the schlieren that can include sidewall interactions and off-centerline shock motion unaffected by the PM. Additionally, a shock foot tracking algorithm was used for a direct dynamic signal representative of the separation shock motion. Due to the complexity of the interaction and the path-wise integrated nature of the snapshots, these results are considered less reliable.Mechanical Engineerin
Siempre Nos Ayudamos: Community Care and Chronic Disaster in Puerto Rico
Full text linkThis dissertation examines how care is practiced, adapted, and sustained among older adults in Aguadilla, Puerto Rico, and within the Boricua diaspora in San Antonio, Texas. Drawing on twelve months of ethnographically informed qualitative research across both sites, it explores how older adults and their families responded to Hurricane María and the COVID-19 pandemic through care, and how these responses contrast with colonial policies that create systemic needs. Centering the lived experiences of older adults, this study highlights how care is negotiated across generations, geographies, and histories of neglect.
Findings reveal that older adults in Aguadilla are often overlooked by the local government systems and instead rely on their community to meet material and emotional needs. I argue that a framework of social connectedness is the foundation of these community responses to disaster, reflecting deeply rooted cultural values of communal responsibility and interdependence. This framework illuminates how care is enacted informally, intergenerationally, and across geographic distance, with older adults both receiving and providing care through reciprocal relationships with their family and community, including those in the diaspora.
Participants consistently described the territorial government as a barrier to recovery, citing a lack of responsiveness and accountability. Their critiques underscore the need for disaster management strategies that move beyond short-term aid and address broader systemic issues such as infrastructure, housing, food security, and healthcare. This dissertation contributes to broader conversations on aging, colonialism, and care by offering a relational, historically grounded perspective on how older Boricuas navigate chronic precarity through community-based care.Anthropolog
Cooperative Control of Multi-Agent Systems and Swarms Moving Towards Large-Scale Control of Vehicles
Full text linkMulti-agent systems (MAS) and swarm control have become one of the most active areas of advanced control research in recent years. MAS and swarm control encompass a broad range of mathematics and disciplines, with applications ranging from military to civilian, from network analysis to energy storage systems to search and rescue. Disciplines from mathematics, engineering, and computer science equally contribute to, and benefit from, the research in MAS and swarm control. The work presents a novel MAS control strategy designed to minimize communication in vehicle-based cooperative MAS (VC-MAS), along with a review of the mathematical necessities of contemporary MAS and swarm control, and of fundamental algorithms for VC-MAS.Along with the review, selected models from the literature are presented, representing both common methodologies of MAS and swarm control, as well as interesting, novel avenues in the research. The first is a technique called relation-invariable persistent formation (RIPF) control, which dynamically generates a rigid formation structure. The second is distributed containment control, a specialized leader-follower strategy. The third is a brief presentation of multi-layer topologies in leader-follower strategies. The last is a brief overview of event-triggered protocols.Finally, a novel algorithm based on a hybrid-approach, designed to reduce computational complexity of the network, is presented. This algorithm is inspired by several conditions proved in the literature to reduce computational complexity of the MAS/swarm network and guarantee consistency of behavior. It also presents a method of designing MAS/swarm control by separating task management and behavior dynamics of the system. A simulation of the algorithm is presented to verify the utility of the model.Mathematic
Feasibility Analysis of Entanglement-Based Quantum Communication Networks
Full text linkLong-distance quantum communication over optical fiber is limited by exponential attenuation.
Quantum repeaters mitigate this by segmenting the link, creating heralded entanglement
on elementary segments, storing it in quantum memories, and performing entanglement
swapping. In this paper, foundational results on DLCZ-style repeaters and successors are
synthesized, quantify feasibility levers (per-link success, swap success, heralding latency,
multiplexing), and prioritize quantum memory decoherence as the main bottleneck. This
framework was implemented on and is accompanied by a program that uses Gaussian Copula
and Monte Carlo simulations to accurately simulate the system according to set parameters.
Producing a full feasibility report of defined system set to a target throughput rate R.Electrical and Computer Engineerin
The Role of Neighborhood Satisfaction in Urban Tree Planting and Survival: Insights from the EquiTree Program in San Antonio, Texas
Full text linkMunicipal urban tree planting programs play a critical role in enhancing environmental justice, yet the influence of residents’ neighborhood perceptions on program participation remains understudied. This study investigates the role of neighborhood satisfaction in tree planting decisions and long-term survival outcomes within the EquiTree program in the City of San Antonio, USA. Using survey data from 306 respondents and logistic regression models, we find that higher neighborhood satisfaction significantly increases both participation in San Antonio’s tree planting program and the likelihood of tree survival. While neighborhood and property tree canopy coverage influence initial participation, they do not significantly impact survival rates, suggesting that personal commitment and community sentiment play a stronger role in tree survival efforts. These findings underscore the importance of neighborhood environment and community-based engagement strategies, including resident education on tree care, to enhance participation and survival efforts.Architecture and Plannin
Leaf Developmental Stages Strongly Modulate Indole Emissions in Response to Simulated Insect Herbivory
Full text linkMaize plants challenged by insect herbivores activate an array of defense measures, all aimed to reduce damage and repel the attacker . Among those are the activation of proteins that interfere with the digestion of consumed plant material in the herbivore (proteinase inhibitors), the production of toxic compounds like benzoxazinoids, and the biosynthesis and emission of herbivore-induced plant volatiles (HIPVs). Among those HIPVs are mainly a variety of terpenoids, green leaf volatiles (GLVs), and indole. While often serving as attractants for natural enemies of the attacking herbivores, many of those volatiles have also been found to induce defense responses in neighboring plants and/or prime them against future menace. Indole is of particular interest since it can be involved in a variety of biosynthetic pathways including those leading to auxin, benzoxazinoids, and tryptophan. Here, we demonstrate that indole emissions in response to simulated insect herbivory by treatment with an insect elicitor (N-linolenoyl glutamine) strongly depend on the developmental status of the affected leaf in maize. Outgrown leaves emit significantly higher amounts of indole compared to the next younger, still growing leaves, distinguishing indole from other HIPVs, which are typically released at higher levels by young leaves. As a central and flexible metabolic intermediate, indole emissions appear to be mediated through variable allocation between growth-related processes and defense-associated outcomes, depending on the developmental stage of the damaged leaf. These findings highlight the importance of considering plants as inherently dynamic organisms
A Regulatory-Aligned, Risk-Aware Supplier Selection Framework for Medical Device Manufacturing Using MCDM/A-LP Hybrid Model
Full text linkSupplier selection in small-to-medium manufacturing, particularly in the medical device sector presents a unique challenge since it requires balancing regulatory compliance, functional performance, and operational efficiency. Traditional Multi-Criteria Decision-Making and Analysis (MCDM/A) approaches often overlook the eliminatory role of regulations that determine supplier eligibility before evaluation. This study develops a two-stage framework that embeds regulatory and functional eliminatory criteria as a prerequisite to supplier evaluation. The first stage filters suppliers based on compliance, functionality, and essential operational constraints. The second stage integrates Analytic Hierarchy Process (AHP), Fuzzy-TOPSIS, Hierarchical Clustering, and Linear Programming (LP) to weight, rank, and optimize supplier choice under uncertainty. The framework incorporates international regulatory considerations to address variations across bodies such as the FDA and EMA. A case study on compressor supplier selection for a Class II medical device demonstrates how the model effectively narrows the supplier pool while maintaining regulatory and operational alignment. The results show that integrating eliminatory criteria with advanced MCDM/A methods enables a structured, regulation-aware, and globally adaptable supplier selection process suited to small and mid-scale manufacturers.Mechanical Engineerin
An Immunoinformatics-Based Multi-Peptide Vaccine Provides Antibody-Mediated Protection Against Acinetobacter baumannii Infection
Full text linkBackground/Objectives: <i>Acinetobacter baumannii</i> is an opportunistic nosocomial pathogen characterized by its multidrug-resistant (MDR) phenotype, increasing patient mortality and healthcare costs as a result. Previously, we constructed an immunoinformatics-based <i>Acinetobacter</i> Multi-Epitope Vaccine (AMEV2) candidate and demonstrated robust protection against this MDR pathogen. In this study, we delineate the mechanisms of AMEV2-mediated protective immunity. Methods: In vivo passive immunization with AMEV2 antisera and in vitro opsonophagocytic killing assays (OPKAs) were used to assess the critical role of antibody-mediated protection induced by AMEV2 vaccination. Results: The passive transfer of AMEV2 immune sera to na&iuml;ve mice afforded 67% protection in a pulmonary challenge mouse model. Although AMEV2 sera reacts with bacterial antigens, it is not bactericidal on its own and does not enhance the complement-mediated direct killing of <i>A. baumannii</i>. However, OPKAs demonstrate AMEV2 sera enhancement of the killing of <i>A. baumannii</i> in the presence of primary bone marrow-derived macrophages. This killing occurs via complement and Fc gamma receptor-mediated phagocytosis. A highly immunogenic AMEV2 component peptide, pTonB, elicits pTonB-specific antibodies and protection in vivo. The depletion of pTonB antibodies from AMEV2 immune sera by pTonB absorption significantly reduced the opsonophagocytic killing of <i>A. baumannii</i> in vitro. Conclusions: The data presented here demonstrate the importance of humoral immunity and its protective mechanisms against <i>A. baumannii</i>. These findings further expand the in vivo evaluation of in silico-designed vaccines as a viable alternative to combat the current global MDR pathogen health crisis.Molecular Microbiology and Immunolog
Commutative Quaternion Algebra with Quaternion Fourier Transform-Based Alpha-Rooting Color Image Enhancement
No full textIn this paper, we describe the associative and commutative algebra or the (2,2)-model of quaternions with application in color image enhancement. The method of alpha-rooting, which is based on the 2D quaternion discrete Fourier transform (QDFT) is considered. In the (2,2)-model, the aperiodic convolution of quaternion signals can be calculated by the product of their QDFTs. The concept of linear convolution is simple, that is, it is unique, and the reduction of this operation to the multiplication in the frequency domain makes this model very attractive for processing color images. Note that in the traditional quaternion algebra, which is not commutative, the convolution can be chosen in many different ways, and the number of possible QDFTs is infinite. And most importantly, the main property of the traditional Fourier transform that states that the aperiodic convolution is the product of the transform in the frequency domain is not valid. We describe the main property of the (2,2)-model of quaternions, the quaternion exponential functions and convolution. Three methods of alpha-rooting based on the 2D QDFT are presented, and illustrative examples on color image enhancement are given. The image enhancement measures to estimate the quality of the color images are described. Examples of the alpha-rooting enhancement on different color images are given and analyzed with the known histogram equalization and Retinex algorithms. Our experimental results show that the alpha-rooting method in the quaternion space is one of the most effective methods of color image enhancement. Quaternions allow all colors in each pixel to be processed as a whole, rather than individually as is done in traditional processing methods.Electrical and Computer Engineerin
Insights into Persian Gulf Beach Sand Mycobiomes: Promises and Challenges in Fungal Diversity
Full text linkBeach Sand Mycobiome is currently among the most important health challenges for viticulture in the world. Remarkably, the study of fungal communities in coastal beach sand and recreational waters remains underexplored despite their potential implications for human health. This research aimed to assess the prevalence of fungal species and the antifungal susceptibility profiles of fungi recovered from the beaches of the Persian Gulf and the Sea of Oman. Sand and seawater samples from 39 stations distributed within 13 beaches along the coastline were collected between May and July 2023. The grown isolates were identified at the species level based on morphological characteristics and DNA sequencing. Antifungal susceptibility testing was performed according to the Clinical Laboratory Standards Institute guidelines. Of 222 recovered isolates, 206 (92.8%) filamentous fungi and 16 (7.2%) yeast strains were identified. Sand-recovered fungi comprised 82.9%, while water-originated fungi accounted for 17.1%. The DNA sequencing technique categorized 191 isolates into 13 genera and 26 species. The most recovered genus was <i>Aspergillus</i> (68.9%), and <i>Aspergillus terreus sensu stricto</i> was the commonly identified species (26.14%). Voriconazole was the most effective antifungal drug against <i>Aspergillus</i> species. Research on fungal contamination levels at these locations could provide a foundation for establishing regulatory frameworks to diminish fungal risks, thereby enhancing public health protection. The ecological significance of fungal communities in sandy beaches to human infections remains to be explored, and earlier reports in the literature may motivate researchers to focus on detecting this mycobiome in natural environments where further investigation is warranted. Ultimately, our discovery serves as a reminder that much remains to be learned about pathogenic fungi and underscores the need for vigilance in areas where emerging pathogens have not yet been identified.Molecular Microbiology & Immunolog