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Comprehensive assessment of deep reinforcement learning approaches for economic dispatch in nuclear-driven microgrids
Get PDFAs the electrical grid integrates more variable renewable energy sources such as wind and solar, the demand for distributed and flexible systems to address this increased variability becomes critical. Nuclear-driven microgrids provide a promising solution by offering stable generation to complement intermittent renewables, ensuring grid reliability and operating efficiency. This paper proposes a recurrent deep reinforcement learning framework for optimal economic dispatch in a nuclear-powered microgrid integrating renewable energy sources, small modular reactors, battery storage systems, and balance-of-plant dynamics. A three-agent control architecture is developed, where demand and renewable energy agents act as forecasters, and a reinforcement learning-based dispatch agent performs real-time energy allocation. A nonlinear programming formulation is first used to generate an optimal baseline for benchmarking. The proposed dispatch controller, based on Proximal Policy Optimization enhanced with Long Short-Term Memory networks, exploits temporal correlations in system dynamics by taking advantage of the time series used as inputs to improve policy robustness under uncertainty. Comparative analysis against established deep reinforcement learning methods, including Proximal Policy Optimization with a feedforward architecture, Soft Actor-Critic, and Twin Delayed Deep Deterministic Policy Gradient, demonstrates superior performance. Numerical results indicate that the proposed controller achieves a 0.39% cost reduction relative to the nonlinear programming benchmark and outperforms other learning-based methods by generating additional revenue of up to 0.35%. All reinforcement learning controllers compute dispatch actions in less than 0.3 s, resulting in a computational speedup of more than three orders of magnitude over the nonlinear programming baseline. The findings of this paper highlight their applicability for real-time operation and control in nuclear-integrated microgrids under volatile operating conditions.Electrical and Computer Engineerin
Urban Impacts on Water Quality and Bioretention Efficacy as a Nature-Based Solution (NbS) Under Varying Media and Construction Practices in South Central Texas
Get PDFIn this study, water quality responses to an urbanization gradient and precipitation patterns were evaluated in the Upper Leon Creek (ULW) watershed. Additionally, water quality treatment performance of four bioretention nature-based solutions (NbS) on the UT San Antonio (UTSA) campus and four biomedia mixes using a column test was assessed. E. coli and NO₃-N were significantly higher in first-flush samples from urban streams compared to rural streams, and multiple pollutants (Cr, Pb, TKN, TN, NO₃-N, NO₂-N, TSS, TOC, organic content of TOC) were significantly higher in first-flush samples compared to second-flush samples, confirming a strong first-flush signal. Only chromium and barium showed a significant dilution effect with increasing precipitation amount, while TOC and NO2-N responses to precipitation significantly differed in urban and rural areas, suggesting a shift in source contributions. Several metals, TOC, and salinity increased with increasing antecedent dry days or regional drought, suggesting significant consistent accumulation over time only for these pollutants. Two basins reduced Cu and E. coli, two showed significant reductions in nutrients and TSS, and one significantly reduced turbidity, organic content, and zinc. Ionic indicators (specific conductance, TDS, salinity, pH) were significantly higher in effluent for all NbS, reflecting media contact with solids contributed from construction. Results indicate bioretention NbS can treat multiple pollutants, though performance is impacted by deficiencies. Column comparisons of four biomedia treatments showed significantly reduced E. coli of influent to effluent in all treatments, and only one showed significantly reduced TSS over the baseline. Small departures from the specified mix produced minimal differences in treatment efficacy. Application of study results to future water quality treatment with NbS is discussed.Civil and Environmental Engineerin
AI-Enabled Sustainable Manufacturing: Intelligent Package Integrity Monitoring for Waste Reduction in Supply Chains
Get PDFDespite advances in automation, the global manufacturing sector continues to rely heavily on manual package inspection, creating bottlenecks in production and increasing labor demands. Although disruptive technologies such as big data analytics, smart sensors, and machine learning have revolutionized industrial connectivity and strategic decision-making, real-time quality control (QC) on conveyor lines remains predominantly analog. This study proposes an intelligent package integrity monitoring system that integrates waste reduction strategies with both narrow and Generative AI approaches. Narrow AI models were deployed to detect package damage at full line speed, aiming to minimize manual intervention and reduce waste. Using a synthetically generated dataset of 200 paired top-and-side package images, we developed and evaluated 10 distinct detection pipelines combining various algorithms, image enhancements, model architectures, and data processing strategies. Several pipeline variants demonstrated high accuracy, precision, and recall, particularly those utilizing a YOLO v8 segmentation model. Notably, targeted preprocessing increased top-view MobileNetV2 accuracy from chance to 67.5%, advanced feature extractors with full enhancements achieved 77.5%, and a segmentation-based ensemble with feature extraction and binary classification reached 92.5% accuracy. These results underscore the feasibility of deploying AI-driven, real-time QC systems for sustainable and efficient manufacturing operations.Mechanical, Aerospace, and Industrial Engineerin
From Academic Idea to Small Business: A Narrative Description of the Processes of a Sole-Proprietor
Get PDFAn earlier version of this paper was presented at the 36th annual conference of the International Academy of Business Disciplines, Orlando, FL, April 4, 2025.Developing an idea into a small business is no easy task, especially when that idea germinates in the mind of an academic teacher-scholar. Many professional academics may lack the experience or knowledge to start a business. Research literature on business development tends to take on a theoretical approach as in Galbraith’s (1982) description of the “stages of growth” for new business ventures. Indeed, Scott and Bruce (1987) broke down the growth process into five distinct stages for small businesses: a) inception, b) survival, c) growth, d) expansion, and e) maturity. More re-cent research (Griva, et al., 2023) demonstrates that these ideas about growth of small businesses may apply differentially to digital start-ups. As a case study, Stat Tree LLC, registered in 2021, is a digital start-up small business began by a faculty member as a project for his classes. This faculty member had to learn the process of starting a business through doing. This paper describes the process of starting a small business from idea generation to commercial production from the perspective of an academic first and sole-proprietor small business owner second.Communicatio
Special Issue: Electron Diffraction and Structural Imaging—Volume II
Get PDFFollowing the success of the first edition of our Special Issue "Electron Diffraction and Structural Imaging", we present Volume II, featuring new and innovative contributions that further expand the scope and depth of this rapidly evolving field [...]Physics and Astronom
In Vivo Comparison of Resin-Modified and Pure Calcium-Silicate Cements for Direct Pulp Capping
Get PDFIntroduction: Direct pulp capping (DPC) aims to preserve the vitality of the dental pulp by placing a protective biocompatible material over the exposed pulp tissue to facilitate healing. There are several calcium-silicate materials that have been designed to promote mineralization and the regulation of inflammation. These have strong potential for the repair and regeneration of dental pulp. Among them, Biodentine (BD) and EndoSequence RRM Putty (ES) have been found to promote in vitro and in vivo mineralization while minimizing some of the limitations of the first-generation calcium-silicate-based materials. Theracal-LC (TLC), a light-cured, resin-modified calcium-silicate material, is a newer product with potential to improve the clinical outcomes of DPC, but existing studies have reported conflicting findings regarding its biocompatibility and ability to support pulpal healing in direct contact with the pulp. A comprehensive assessment of the biocompatibility and pulpal protection provided by these three capping materials has not yet been performed. Aim: We aimed to quantify the inflammatory response, dentin bridge formation, and material adaptation following DPC using three calcium-silicate materials: ES, BD, and TLC. Materials and Methods: DPC was performed on the maxillary first molar of C57BL/6 female mice. Maxilla were collected and processed at 1 and 21 days post-DPC. The early inflammatory response was measured 24 h post-procedure using confocal imaging of anti-Lys6G6C, which indicates the extent of neutrophil and monocyte infiltration. Reparative mineralized bridge formation was assessed at 21 days post-procedure using high-resolution micro-computed tomography (micro-CT) and histology. Lastly, the homogeneity of the capping materials was evaluated by quantifying voids in calcium-silicate restorations using micro-CT. Results: DPC using TLC induced less infiltration of Lys6G6C<sup>+</sup> cells at 24 h than BD or ES. BD promoted higher volumes of tertiary dentin than TLC, but TLC and ES showed no significant differences in volume. No differences were observed in material adaptation and void spaces among the three capping materials. Conclusions: All three materials under investigation supported pulp healing and maintained marginal integrity. However, TLC induced a lower inflammatory response on day 1 and induced similar levels of tertiary dentin to ES. These observations challenge the common perception that resin-based capping materials are not suitable for direct pulp capping. Our findings underscore the need to balance biological responses with physical properties when selecting pulp capping materials to improve long-term clinical success.Endodontics, School of Dentistr
The Legacy of Civil War Repression on Galician Separatism
Get PDFThis thesis examines the relationship between Nationalist (or Francoist) repression in Galicia during the Spanish Civil War and modern support for Galician independence from Spain. ndent paragraph. This aims to contribute to a burgeoning research into legacies of political repression. By using a qualitative methods analysis, this study finds that Galician municipalities that experienced a high rate of repression during the Civil War are more likely to have a higher vote share for the pro-independence political party today. This thesis argues that modern Galicians identify parties that advocate for reduced autonomy with Franco’s regime, which espoused the same attitude and which motivated wartime repression, and, in response, reject the identity of the perpetrator by voting for independence against the perceived perpetrator’s interests. This anti-perpetrator attitude is transmitted over time through the community socialization mechanism, as demonstrated through a qualitative analysis of environmental characteristics and social networks present in a case study within the region.Global Affair
Glider-Based Observations of Physical and Biogeochemical Variability in the Gulf of Mexico
Get PDFThis dissertation presents glider-based observations of physical and biogeochemical variability in the northern Gulf of Mexico during two Fall 2015 autonomous missions. The gliders recorded high-resolution vertical profiles of temperature, salinity, chlorophyll-a, dissolved oxygen, and colored dissolved organic matter to depths of 1000 meters. The first component of the study uses thermal-wind balance combined with the glider's depth-averaged drift to compute cross-track absolute geostrophic velocities, revealing a northward-flowing Loop Current exceeding 1 m s-1 and intensifying as it approaches the shelf break. These velocity fields were validated against OSCAR satellite-derived surface currents, yielding a significant correlation coefficient of 0.74, indicating a good agreement between these two current estimates. The second component shows that upper-ocean chlorophyll variability is dominated by a persistent subsurface chlorophyll maximum, while surface concentrations respond to strong atmospheric forcing, such as wind, precipitation, waves, and Ekman pumping, which can shoal the subsurface layer and produce short-lived surface chlorophyll peaks often undetected by satellites. The third component documents a subsurface intrathermocline eddy (ITE) sampled along a glider transect. The ITE exhibited a warm, saline anticyclonic lens structure between 60-250 m depth, dynamically isolated and with suppressed stratification and depressed potential vorticity. These observations demonstrate the glider’s capability to resolve both surface and thermocline-trapped mesoscale features, supporting their role in lateral transport and ventilation in the ocean interior. Collectively, this work emphasizes the value of autonomous gliders for studying fine-scale ocean circulation and its influence on biogeochemical variability in dynamically active regions like the Gulf of Mexico.Civil and Environmental Engineerin
Assay Development for Tau-directed Therapeutics
No full textThe full text of this item is not available at this time because the author has placed this item under an embargo until February 26, 2026.Neurofibrillary tangles (NFTs) are intracellular aggregates comprised of the microtubule-associated protein tau. These insoluble aggregates are found in the brain of those affected by Alzheimer’s disease and other related tauopathies. Advancements in cryo-electron microscopy over the last few years have revealed that structures of these aggregates found in various diseases are distinct from one another. They differ in terms of the amino acids participating in the folds of the aggregates, as well as the number and positioning of the beta-sheets. In vitro induced tau filaments commonly used to screen therapeutics have also been observed to have structures which are not similar to those found in diseases. We hypothesize that screening therapeutics against tau aggregates with structures similar to those observed in disease may allow for the identification of more effective therapeutics.
In order to identify conditions to induce disease-relevant aggregates and develop assays to screen therapeutics, this study explores mechanical shaking-induced aggregation and RNA-induced aggregation, as well as the effect of a commonly observed post-translational modification in NFTs, hyperphosphorylation, on tau aggregation. We observed that mechanical shaking of various constructs of tau, which have been published to form AD-relevant structures, results in highly variable filament formation. These conditions also require extremely high concentrations of protein, which are not suitable for robust and reproducible assays to identify inhibition or disassembly of filaments. RNA-induced aggregation was investigated to induce aggregation in a reliable and reproducible manner at lower concentrations of protein. Although the formation of filaments with twists, an important characteristic of those found in disease, was observed with RNA-induced tau aggregation, extremely low filament formation with variability hinders the potential use of these conditions for tau-directed assay development. These results emphasize the need for the development of reliable assays at concentrations of protein suitable for the detection of changes in filament formation. Variants of pseudophosphorylated tau, used to mimic phosphorylation, which have been observed to form AD-relevant aggregates in vitro by others at high concentrations with shaking, generate reproducible filaments with observable twists with low-resolution microscopy, with polyphosphate-induced aggregation. Full-length pseudophosphorylated tau variants showed that the number of modified sites affects tau aggregation and microtubule stability. Incorporation of post-translational modifications in in vitro experiments may help better mimic and understand disease conditions, as well as help in identifying conditions and designing protocols for the generation of disease-relevant aggregates. These efforts may lead to a better understanding of these diseases and simultaneously lead to the identification of therapeutics for tau aggregation and help in finding a much-needed cure.Neuroscience, Developmental and Regenerative Biolog
Auditors&rsquo; Life Cycle in Clients and Auditor Independence
Get PDFThis study hypothesizes that, in client firms, audit teams or auditors go through life cycle phases&mdash;<i>entry</i>, <i>adjustment</i>, and <i>recursion</i>&mdash;that give rise to distinct patterns of independence across time. The <i>life cycle paradigm</i> depicts the auditors as facing pressures during entry to adhere strongly to their professional mandate, including the strict exercise of independence. The result is tense auditor&ndash;client relations and an increased likelihood of auditor turnover during the <i>entry</i> phase. Auditors that gain entry will &ldquo;loosen up&rdquo; and adjust their stance on independence due to the reduced entry pressures. As a result, the <i>adjustment</i> phase will witness a decline in auditor&ndash;client disagreements and a lower likelihood of auditor turnover. Over protracted periods, the audit process becomes tightly structured and recursive; the repetitive nature of the processes leads to audit fatigue, less attention to the independence mandate, and greater reliance on clients. The phenomenon portends an even further decline in auditor&ndash;client tension and a diminished likelihood of auditor turnover. These predictions are tested using auditor turnovers following auditor&ndash;client disputes as surrogates for auditor independence. The results confirm the life cycle phenomena and show that the level of auditor independence peaks during the early years of the auditors&rsquo; tenure and declines afterwards.Accountin