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Mechanical and microstructural characterization of nuclear grade PCEA graphite
No full textThis thesis presents a comprehensive experimental characterization of PCEA (Petroleum Coke Extruded and Annealed) nuclear-grade graphite with emphasis on its density uniformity, elastic and strength properties, and microstructural fracture mechanisms. Bulk density measurements showed that PCEA graphite exhibits excellent homogeneity, with no measurable anisotropy between with-grain and against-grain orientations. A slight radial density gradient was identified, with marginally higher densities at the billet periphery, a trend consistently reflected in the mechanical properties. Dynamic Young’s and shear moduli obtained from fundamental frequency resonance testing revealed minor elastic anisotropy and narrow data scatter, indicating high structural uniformity. Comparison of static and dynamic modulus values demonstrated that microcrack closure and frictional effects strongly influence stiffness during static loading, while dynamic measurements capture the intrinsic crystalline elastic response. Flexural, tensile, and compressive strength tests confirmed that the edge region of the billet exhibits slightly higher mechanical performance than the center, correlating with local density variations. Tensile and split-disk tests produced comparable strength values, with the split-disk method showing reduced variability and thus offering a reliable, space-efficient alternative for irradiation studies. Weibull statistical analysis across all mechanical tests verified predictable quasi-brittle behavior and provided representative reliability parameters.
Digital Image Correlation (DIC) revealed fundamentally different deformation mechanisms under tension and compression. Tensile loading produced linear elastic behavior followed by abrupt fracture initiated at microstructural flaws, whereas compression induced non-linear stress–strain response governed by pore collapse, crack closure, shear banding, and progressive damage accumulation. Microstructural observations using SEM identified the heterogeneous filler–binder–pore network characteristic of PCEA graphite and linked fracture behavior to mechanisms such as crack deflection, branching, and ligament bridging. Collectively, these results establish a robust understanding structure and properties of PCEA graphite, confirming its mechanical reliability and providing essential baseline data for its potential application in high-temperature nuclear reactor components.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-12-01The student, Tamim Hossain, accepted the attached license on 2025-12-10 at 15:14.The student, Tamim Hossain, submitted this Thesis for approval on 2025-12-10 at 15:26.This Thesis was approved for publication on 2025-12-11 at 13:26.DSpace SAF Submission Ingestion Package generated from Vireo submission #23128 on 2026-02-19 at 20:10:1
Investigation of mechanical behavior and microstructural characteristics of diffusion bonded 316H stainless steel for compact heat exchanger applications
No full textCompact heat exchangers (CHX) are key components for advanced energy systems that require high heat-transfer capacity at elevated temperatures. Diffusion bonding has been an effective technique for the fabrication of joints in heat exchanger applications. However, the structural integrity of the diffusion bonded joints is critical. Type 316H austenitic stainless steel has been a candidate material for CHX applications for their creep resistance and high temperature mechanical performances.
In this study, nine different diffusion bonding conditions for 316H stainless steel have been investigated using mechanical testing and microstructural analysis. Tensile tests and microtensile tests were performed at room temperature and 760℃ on the diffusion bonded and wrought 316H SS specimens to analyze the bond strengths in comparison to the wrought samples. The room temperature tests showed promising results for several trials including CompRex Trial 5 and Trial 6. However, the elevated temperature results showed that the CompRex Trial 6 (bonding carried out at 1150℃ with 8 MPa pressure and 4 hours of holding time) displayed the best combination of strength and ductility among all the bonding conditions. The microtensile tests performed at room temperature also showed ductile failures and the failures did not occur on the bond interfaces. Digital Image Correlation (DIC) was also used to characterize the material deformation over time. Creep test was performed on the CompRex Trial 6 316H SS at 760℃ with 75 MPa stress, and results showed good fraction of secondary creep before moving to tertiary creep regime. Microhardness tests conducted on the different regions of the gauge section of creep sample showed that the brittle failure mode resulted from the creep strain hardening in the bulk region rather than weak debonding of the bond interfaces. Along with that, shear punch tests performed at room temperature and 760℃ showed that no bond delamination occurred under shear stress. Dye penetrant tests were also helpful in identifying some weaker bonds in the gauge section.
The SEM fracture surfaces of the tensile tests showed that the CompRex Trial 6 underwent ductile fracture at elevated temperature which is more comparable to the wrought fracture surface. EBSD performed in the region across the bond interfaces have shown signs of grain growth in CompRex Trial 5 and Trial 6. For the other trials, the tensile results were not promising enough as they showed brittle debonding on the bond interfaces. TEM and STEM EDS were performed to identify any precipitate or cavities across the bond interfaces. The CompRex Trial 6 316H SS did not show any signs of precipitates on the bond interfaces, while STEM EDS of the CompRex Trial 5 showed small presence of Al2O3 (alumina) particle near the bond interfaces. In addition to that, optical microscopy and MIPAR analysis was also carried out on CompRex Trial 4, 5 and 6 bonds. MIPAR results showed higher percentage of grains penetrating the bond interfaces for CompRex Trial 6 in comparison with other trials.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2027-12-01The student, Intisher Al-Tahmid Omi, accepted the attached license on 2025-12-10 at 20:25.The student, Intisher Al-Tahmid Omi, submitted this Thesis for approval on 2025-12-10 at 20:47.This Thesis was approved for publication on 2025-12-11 at 13:18.DSpace SAF Submission Ingestion Package generated from Vireo submission #23132 on 2026-02-19 at 20:10:1
Русская церковь и европейское Просвещение: новый взгляд
Get PDFРецензия на: A. V. Ivanov, A Spiritual Revolution: The Impact of Reformation and Enlightenment in Orthodox Russia. Madison, WI: The University of Wisconsin Press, 2020. 353 p. ISBN 9780299327903
Русские в Париже XVIII века под бдительным оком полиции
Get PDFРецензия на: Dzianis Kandakou, Alexandre Stroev. Les Russes à Paris au XVIIIe siècle sous l’oeil de la police. Paris: L’Harmattan, 2024. 736 p. ISBN: 9782336406572
Новая точка входа в изучение ранненововременной квир-истории России
Get PDFReview of: Hanna Filiopova. Male Same-Sex Relations and the Court of Peter I: Turning Muscovite. Cham: Palgrave Macmillan, 2025. 134 p. ISBN: 9783031954801
Sulle strade del teatro: l’epico viaggio della compagnia teatrale di Giovanni Battista Locatelli verso San Pietroburgo attraverso il “Racconto breve” di Angelo Carboni
Get PDFThis article is dedicated to the journey undertaken by the Bolognese painter Angelo Carboni from Italy to Saint Petersburg in the mid-eighteenth century, together with the theatrical company led by Giambattista Locatelli. At the centre of the study is the Racconto breve del lungo viaggio intrapreso, proseguito e terminato sino a Peterburgh dal signor Angelo Carboni cittadino bolognese, pittore, written by Carboni and presented in transcription in the second part of the contribution. The source provides valuable information on eighteenth-century travel practices, including the duration of the journey, the itinerary followed, the costs involved, as well as the dangers that travellers might encounter, such as a violent storm in the Baltic Sea or arrest on charges of espionage. Alongside these practical aspects, the testimony offers reflections on how an eighteenth-century artist perceived relocation abroad. The transcription is accompanied by an apparatus of notes and an introductory essay aimed at contextualising the journey within the framework of the European activity of Giambattista Locatelli’s theatrical company. A central element of the contribution is the systematic comparison between Carboni’s account and contemporary documentary sources, which has made it possible to clarify the historical context and assess the degree of reliability of the testimony. In this way, the article contributes to the study of artistic mobility, travel practices, and the cultural networks linking Italy and Russia in the eighteenth century
Blank slate characters: Gateways to affect and emotion in Itō Junji’s manga
No full textThis article explores the function of characters as emotional conduits in the horror manga of Itô Junji, defining and analyzing his use of what this paper terms the “Blank Slate Character.” Aligned with the realistic gekiga style that emerged as a counterpoint to mainstream manga, Itô’s aesthetic deliberately employs archetypal figures with generic features rather than psychologically complex protagonists. This article argues that these intentionally simple characters, serve as ideal vessels for reader projection, affective mimicry, and somatic empathy, precisely because of their visual and psychological neutrality. Drawing on philosophical frameworks from horror theory and film studies, this article analyzes how dynamics like asymmetrical identification and sympathy are amplified through such characterization. Through extensive close readings of extracts of Itô’s seminal works like Gyo and one of the stories from the series Tomie, this article demonstrates how specific visual strategies, particularly the cinematic use of extreme close-ups, transform these simplistic figures into a focal point of intense emotion, thereby heightening the reader’s immersion. This work further proves that somatic empathy is fundamental to Itô’s brand of horror, contending that the vulnerability of a deliberately underdeveloped protagonist makes the depiction of bodily harm more universally resonant. Ultimately, this character-building philosophy reflects Itô’s acknowledged focus on the central horror phenomenon over his protagonists. Consequently, what might be perceived as a narrative weakness—the lack of deep characterization—is actually strategic, repurposed to bypass complex psychological identification in order to instead forge a direct and powerful somatic engagement with the reader
Tezuka’s literary robot: Instrumentalism, sentimentalism, and mech-aesthesis in Mighty Atom
No full textThis article investigates how the robot literature of Unno Jûza and Karel Čapek establishes the legibility of Osamu Tezuka’s most influential robot character: the "child of science" Atom from the manga series Mighty Atom (Astro Boy). While critics have noted specific allusions to Unno and Čapek in Tezuka’s work, this article posits that the influence of these authors exceeds limited sources of reference material. Instead, it argues that through Mighty Atom Tezuka performs a strong misreading of Unno’s fiction by re-interpreting themes and motifs of technoscientific autonomy sourced from Unno through a form of humanism derived from Čapek’s Rossum’s Universal Robots (1920). The first section discusses how Unno’s robot fiction entangles technoscientific autonomy and nationalistic instrumentalism. The second section demonstrates how Tezuka transforms this discourse through reading Tezuka's Doctor Mars (1947) and Mighty Atom (1952-1968) alongside the Unno novel Chikyû yôsai (1941, transl. Earth Fortress). The third section establishes how Čapek furnishes a model for the reorientation of technoscientific autonomy toward the sensitive heroism of Atom. The article concludes by reflecting on how this revision of Unno through Čapek inheres within robot science fiction comics and animation succeeding Mighty Atom
Abstraction and application: complementary perspectives on sociotechnical systems
Get PDFAlgorithmic and technological systems are often developed using abstract models and objectives, but are ultimately used for specialized real-world applications; the gap between these levels of design and use often leads to unmet user needs or amplified harms at scale. Addressing this gap benefits from examining the two ends of the methodological spectrum for adapting generalized technologies to specific real-world contexts, namely abstraction-first and application-first approaches. This dissertation examines these perspectives through two parts, each comprising three projects that share a common methodological lens and research focus. While each part explores a different problem space, they offer complementary insights into how generalized technologies can be adapted to specific real-world settings.
The first part examines the abstraction-first perspective, in which algorithms are developed according to abstract models that are modified to capture potential realities of actual use. It begins with classical metric clustering problems such as k-center and facility location, which often underpin machine learning and resource allocation algorithms where real-world concerns such as fairness have become especially relevant. The first two chapters develop constant-factor approximation algorithms for clustering formulations that aim to ensure fairness for each individual point being clustered, later extending these results to address fairness at the group level as well. The final chapter broadens the scope to the more general class of covering problems, analyzing fairness-constrained formulations under assumptions motivated by real-world applications. These results yield constant-factor approximations in settings where no such bounds were previously known and, in some cases, improve existing guarantees. While this perspective contributes flexible results that can be applied across a wide variety of contexts, it does not provide guidance for practical use; rather, it demonstrates the feasibility of incorporating practical considerations into classical models without prescribing how they should be applied in real-world settings.
The second part takes an application-first perspective that explores real-world contexts to identify opportunities for technological abstraction or intervention, focusing on the domain of online community moderation. The first chapter in this part examines the broad landscape of platforms and the technological features that shape their governance structures, and the following two chapters focus on a specific platform and feature: Reddit’s moderation queue, which enables community-specific human review of reported content. This perspective illustrates how technological abstractions can emerge from studying real-world practices and highlights the factors that shape the design and use of moderation tools. While it offers insights into the mechanics of sociotechnical systems and informs design and policy interventions, these insights are inherently limited in generalizability and longevity as applications and user practices continue to evolve in ways that can transcend existing abstractions.
Placing these two bodies of work side by side, each grounded in a distinct methodological paradigm, underscores how each frames, constrains, and enables different kinds of progress within sociotechnical research. This dissertation concludes with broader reflections on abstraction- versus application-first perspectives and emphasizes that neither perspective is sufficient on its own; effective inquiry depends on feedback loops between them, where abstractions are continually grounded in real-world contexts and empirical insights inform new abstractions. It also outlines avenues for integrating these methodological perspectives and highlights the importance of addressing the tradeoffs inherent in building technologies and theories that are both principled and aligned with the complexities of use.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2026-02-19 without embargo termsThe student, Tanvi Bajpai, accepted the attached license on 2025-11-17 at 19:34.The student, Tanvi Bajpai, submitted this Dissertation for approval on 2025-11-17 at 19:42.This Dissertation was approved for publication on 2025-11-19 at 15:42.DSpace SAF Submission Ingestion Package generated from Vireo submission #22879 on 2026-02-19 at 18:24:5
Acies-OS: a twin-assisted systems architecture for edge intelligence
Get PDFThe rapid proliferation of Artificial Intelligence (AI) within the Internet of Things (IoT) and Cyber-Physical Systems (CPS) has created new opportunities for intelligent sensing, perception, and control at the network edge. However, deploying deep learning-based intelligence on embedded platforms introduces fundamental challenges, including limited computational resources, thermal constraints, and unreliable network connectivity. Addressing these challenges requires system-level innovation that spans from performance modeling and resource optimization to workflow orchestration and adaptive learning.
This dissertation introduces Acies-OS, a twin-assisted, content-centric middleware framework designed to enhance the efficiency and robustness of distributed edge intelligence systems. Acies-OS unifies data, computation, and control under a structured namespace abstraction, allowing distributed nodes to coordinate seamlessly through declarative data and control interfaces. Its design combines efficient latency and thermal modeling for performance optimization, a digital twin mechanism for cross-layer monitoring and failover recovery, and an extensible control plane for implementing runtime optimization services such as model selection and workflow reconfiguration. Together, these mechanisms enable dynamic, data-driven management of complex sensing-to-decision workflows in resource-constrained environments.
The dissertation further introduces an unsupervised collaborative adaptation framework that enables in-situ model refinement at runtime without labeled data. By leveraging spatial and temporal correlations across distributed sensors, this approach improves model robustness against domain shifts encountered in real deployments. The system is implemented and evaluated using a multi-modal, multi-node vehicle classification testbed that has supported numerous research efforts and produced the largest publicly available dataset of its kind. Finally, the dissertation outlines a design for extending Acies-OS toward agentic edge intelligence, integrating large language model (LLM)-based agents with cyber-physical systems through standardized control interfaces.
Overall, this work presents an integrated architecture that advances the efficiency, adaptability, and resilience of edge AI systems. By connecting AI optimization, system middleware, and digital twinning within a unified framework, Acies-OS offers a practical step toward enabling intelligent and self-managing IoT and CPS deployments.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2026-02-19 without embargo termsThe student, Jinyang Li, accepted the attached license on 2025-11-25 at 16:20.The student, Jinyang Li, submitted this Dissertation for approval on 2025-11-25 at 16:28.This Dissertation was approved for publication on 2025-11-26 at 10:17.DSpace SAF Submission Ingestion Package generated from Vireo submission #22955 on 2026-02-19 at 18:25:2