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Articles 13711 - 13740 of 198025

Full-Text Articles in Engineering

Green-Synthesized Yttrium-Doped Cerium Oxide Nanoparticles: A Promising Optical Material, Sasmita Sarangi, Nibedita Nayak, Binita Nanda, Tapas Sahoo Jan 2025

Green-Synthesized Yttrium-Doped Cerium Oxide Nanoparticles: A Promising Optical Material, Sasmita Sarangi, Nibedita Nayak, Binita Nanda, Tapas Sahoo

Journal of Metals, Materials and Minerals

This work focuses on the green synthesis, characterization, and optical properties of yttrium-doped cerium dioxide (CeO2) nanoparticles. A green approach was adopted using Acacia concinna fruit extract as surfactant and stabilizing agent. Their structural, morphological, and physical-chemical properties were characterized using different analytical techniques, like XRD, FE-SEM, FTIR, PL, Raman, UV-Visible Spectroscopy. XRD study validated the structure of cubic fluorite-type structure of CeO2 nanoparticles, with the average crystallite size ranging between 7-15 nm. Raman spectroscopy validated this structure with F2g band observed at 463 cm−1. FESEM images showed irregular spherical morphologies with grain sizes in the range of 50-60 nm. …

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Pyrolysis And Modification Of Coconut Shell Into Sulfonated Biochar And Its Catalytic Activity On Cellobiose Conversion, Addy Rachmat, Yessi Eka Wahyu, Poedji Loekitowati Hariani, Fahma Riyanti, Fatma Fatma Jan 2025

Pyrolysis And Modification Of Coconut Shell Into Sulfonated Biochar And Its Catalytic Activity On Cellobiose Conversion, Addy Rachmat, Yessi Eka Wahyu, Poedji Loekitowati Hariani, Fahma Riyanti, Fatma Fatma

Journal of Metals, Materials and Minerals

Coconut shell was successfully valorized into sulfonated biochar through carbonization in various temperatures and duration. This work aims to provide suitable solid acid carbonaceous catalyst for cellobiose conversion into valuable product. Sulfonated biochar is characterized to evaluate its crystallinity, sulfonate, and oxygenated functional groups by XRD method and FTIR spectroscopy. The resulting solid acid carbonaceous material was tested toward cellobiose hydrolysis to assess its catalytic activity in various time, temperature, and catalyst weight. FTIR spectra reveals some of the biochar product has sulfonate group as indicated by absorbance band at 1234 cm‒1, 1070 cm‒1 and 1180 cm‒1, which belongs to …

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Macro-Encapsulation Of Polyethylene Glycol And Magnetite (Fe3o4) In Concrete As Phase Change Materials For Building Thermal Management, Muhammad Fauzi, Budhy Kurniawan, Anggito Pringgo Tetuko, Timbangen Sembiring, Fanna Nilam, Amdy Fachredzy, Perdamean Sebayang Jan 2025

Macro-Encapsulation Of Polyethylene Glycol And Magnetite (Fe3o4) In Concrete As Phase Change Materials For Building Thermal Management, Muhammad Fauzi, Budhy Kurniawan, Anggito Pringgo Tetuko, Timbangen Sembiring, Fanna Nilam, Amdy Fachredzy, Perdamean Sebayang

Journal of Metals, Materials and Minerals

Thermal management technology is a crucial strategy for reducing energy consumption in buildings by utilizing stored solar energy. This study developed a polyethylene glycol (PEG)-based phase-change material (PCM), selected for its superior physicochemical stability, high latent enthalpy, and environmental compatibility. To enhance thermal conductivity, 20 vol% magnetite (Fe₃O₄) was incorporated into the PEG matrix. The composite was synthesized via an ultrasonic-assisted method (37 kHz, 80°C, 1 h). X-ray diffraction (XRD) confirmed the crystalline structure of PEG and the cubic phase of Fe3O4, while Fourier-transform infrared spectroscopy (FTIR) validated the synthesis by identifying Fe–O, C–H, and O–H functional groups. Scanning electron …

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The Effect Of Pt And Pd Decoration On Sno2 Slant Nanorods Fabricated Using Dc Magnetron Sputtering With Oad Technique For Co Gas Sensing Applications, Nampueng Pangpaiboon, Thitiporn Kaewyou, Sethavut Duangchan, Kata Jaruwongrungsee, Manatsawee Srirak, Tossaporn Lertvanithphol, Viyapol Patthanasettakul, Tawee Pogfay, Mati Horprathum, Saksorn Limwichean Jan 2025

The Effect Of Pt And Pd Decoration On Sno2 Slant Nanorods Fabricated Using Dc Magnetron Sputtering With Oad Technique For Co Gas Sensing Applications, Nampueng Pangpaiboon, Thitiporn Kaewyou, Sethavut Duangchan, Kata Jaruwongrungsee, Manatsawee Srirak, Tossaporn Lertvanithphol, Viyapol Patthanasettakul, Tawee Pogfay, Mati Horprathum, Saksorn Limwichean

Journal of Metals, Materials and Minerals

This research investigates the effect of Pt and Pd decoration on the structure of SnO2 slant nanorods (SNRs) films produced using DC magnetron sputtering with Oblique Angle Deposition (OAD), as well as their impact on the films' physical properties and gas sensing applications. Pt and Pd were deposited onto the SnO2 SNRs for the same duration of 20 s each. Following deposition, all the films were heat-treated temperature at 400℃ for 2 h. The characterization of both as-deposited and annealed films involved analyzing the physical morphology using FE-SEM and the crystal structure using GI-XRD. It was observed that the structure …

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Microwave Absorption Properties Of Porous Activated Carbon/Nickel Oxide Composites Derived From Coconut Husks, Mohamad Zul Aqiman Shukeri, Nor Zakiah Yahaya, Ezzan Afifah Zainuddin, Nazri Mahmud, Liyana Zahid, Hasliza A. Rahim Jan 2025

Microwave Absorption Properties Of Porous Activated Carbon/Nickel Oxide Composites Derived From Coconut Husks, Mohamad Zul Aqiman Shukeri, Nor Zakiah Yahaya, Ezzan Afifah Zainuddin, Nazri Mahmud, Liyana Zahid, Hasliza A. Rahim

Journal of Metals, Materials and Minerals

Porous Activated Carbon (AC) is a promising material for microwave absorbing materials, showing potential in communication and modern warfare. The study explores the process of creating porous AC from coconut husks using hydrochloric acid and carbonization at varying temperatures, followed by doping AC with nickel oxide to create an AC/NiO polymer composite with varying thicknesses. These composites are compared to AC composites loaded in a paraffin matrix. The dielectric and microwave (MW) properties of the AC/NiO and AC polymer composites at various thicknesses were analyzed using a Performance (PNA)-X Network Analyzer. The study also examines the carbon content and porosity …

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Improvement In Electrical And Energy Storage Properties Of Lead-Free Bnkt-Bt Piezoceramics, Manlika Kamnoy, Supalak Manotham, Pichitchai Butnoi, Sukum Eitssayeam, Piewpan Parjansri Jan 2025

Improvement In Electrical And Energy Storage Properties Of Lead-Free Bnkt-Bt Piezoceramics, Manlika Kamnoy, Supalak Manotham, Pichitchai Butnoi, Sukum Eitssayeam, Piewpan Parjansri

Journal of Metals, Materials and Minerals

The electrical characteristics and energy storage performance of BNKT-BT lead-free piezoceramics were examined. All ceramics were produced via the mixed oxide technique. The findings indicated that the density of this ceramic system varied between 5.61 and 5.83 g/cm3. Conditions with 2.0 mol% (BT=0.02) and 6.0 mol% (BT=0.06) exhibited the largest dielectric constant (er) at both ambient temperature and elevated temperature, with values of 1307 and 4272, respectively. The ceramic sample with BT = 0.06 exhibited the highest values of %strain ~0.13 and a d*33 ~179.65 pm/V. Furthermore, BT-doped ceramics yielded optimal energy storage densities compared to undoped BNKT ceramics. The …

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Optimization Of Indigo Dyeing On Modal Fabrics Using Thiourea Dioxide As An Environmentally Friendly Reducing Agent, Monthon Nakpathom, Buppha Somboon, Nootsara Narumol, Rattanaphol Mongkholrattanasit, Pisutsaran Chitichotpanya, Nattaya Vuthiganond Jan 2025

Optimization Of Indigo Dyeing On Modal Fabrics Using Thiourea Dioxide As An Environmentally Friendly Reducing Agent, Monthon Nakpathom, Buppha Somboon, Nootsara Narumol, Rattanaphol Mongkholrattanasit, Pisutsaran Chitichotpanya, Nattaya Vuthiganond

Journal of Metals, Materials and Minerals

This investigation examines the potential of thiourea dioxide as an environmentally reducing agent for dyeing of natural indigo on modal fabrics. Although traditional sodium dithionite is effective, its sulfur by-products generate environmental concerns. Thiourea dioxide, which provides a more environmentally friendly alternative, was studied under various dyeing conditions. In this study, six dyeing parameters, including thiourea dioxide and sodium hydroxide concentrations, reduction temperature, reduction duration, dyeing time, and reduction-oxidation cycles, were optimized to enhance color strength. Results indicated that the most favorable reduction conditions were achieved when 80 g/L of thiourea dioxide and 2 g/L of sodium hydroxide were heated …

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Eco-Friendly Synthesis Of Flower-Like Hierarchical Structure Of Cuo Nps For Advancing Photocatalytic Efficiency And Antibacterial Applications, Yodchai Tangjaideborisut, Shanmugam Shanmugam, Supakorn Boonyuen, Govindasamy Siva, Prema Yugala, Joon Ching Juan, Choowin Phanawansombat, Atchariya Pitintharangkul, Seerangaraj Vasantharaj, Pornpan Pungpo, Pariya Na Nakorn Jan 2025

Eco-Friendly Synthesis Of Flower-Like Hierarchical Structure Of Cuo Nps For Advancing Photocatalytic Efficiency And Antibacterial Applications, Yodchai Tangjaideborisut, Shanmugam Shanmugam, Supakorn Boonyuen, Govindasamy Siva, Prema Yugala, Joon Ching Juan, Choowin Phanawansombat, Atchariya Pitintharangkul, Seerangaraj Vasantharaj, Pornpan Pungpo, Pariya Na Nakorn

Journal of Metals, Materials and Minerals

In recent decades, environmental pollution caused by organic dyes and pathogenic microorganisms has posed significant challenges to both ecological and public health. Therefore, the development of multifunctional materials capable of simultaneously degrading dyes and exhibiting antibacterial properties is crucial for effective environmental remediation. Combining photocatalytic dye degradation with antibacterial activity offers a promising approach to address these dual concerns in a single process. The present study investigates the copper oxide nanparticles (CuNPs) were prepared by green synthetic method using bamboo extract for degradation of methylene blue and in inactivation of biological pathogens. The green synthesized CuONPs were characterized various spectroscopic …

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Enhancing Efficiency And Productivity Of Microbial Fuel Cells For Optimization Of Wastewater Treatment With Bioenergy Production, Diptimayee Pradhan, Krishna Pada Bauri, Debarpita Ghosal, Satchidananda Mishra, Abhijeet Das, Aditya Raj Singh, Akhil Gedela, Kumbhakarna Mallik, Mohammed Hassan Ali Hbag Jan 2025

Enhancing Efficiency And Productivity Of Microbial Fuel Cells For Optimization Of Wastewater Treatment With Bioenergy Production, Diptimayee Pradhan, Krishna Pada Bauri, Debarpita Ghosal, Satchidananda Mishra, Abhijeet Das, Aditya Raj Singh, Akhil Gedela, Kumbhakarna Mallik, Mohammed Hassan Ali Hbag

Journal of Metals, Materials and Minerals

The primary objective is to remove the pollutants from the wastewater streams and reintegrate them into the water cycle, therefore safeguarding the environment and promoting public health. The utilization of membrane fuel cells (MFCs) enables the conversion of organic molecules present in wastewater into electrical energy, while concurrently generating potable water. To optimize the process, it is essential to understand the parameters that affect the performance and the relevant techniques such as electrode materials, microbial collectives, and operating settings to improve the efficiency and performance of MFC. Thus, it aims to present novel ideas that support the real-world deployment of …

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A Review On Recent Progress In Supported Magnetic Nanoparticles: From Synthetic Methods To Applications, Khushboo Dhiman, Ayashkanta Nanda, Navneet Kaur, Manvinder Kaur, Harvinder Singh Sohal, Himanshi Sharma, Meenakshi Verma Jan 2025

A Review On Recent Progress In Supported Magnetic Nanoparticles: From Synthetic Methods To Applications, Khushboo Dhiman, Ayashkanta Nanda, Navneet Kaur, Manvinder Kaur, Harvinder Singh Sohal, Himanshi Sharma, Meenakshi Verma

Journal of Metals, Materials and Minerals

Magnetic nanoparticles supported on various materials have recently gained significant attention due to their wide range of applications across multiple fields such as catalysis, biomedicine, environmental remediation, and magnetic separation. The support materials are essential for stabilizing magnetic nano-particles and enhancing their properties, thereby improving their performance and versatility. This review presents a comprehensive summary of recent advancements and key developments in supported magnetic nanoparticles, focusing on various support materials including silica, alumina, cellulose, charcoal, polymeric materials, and carbon nanotubes. We also discussed why we needed a shift from conventional nanoparticles to magnetic nanoparticles and from magnetic nanoparticles to supported …

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Comprehensive Study On The Structural And Optical Properties Of Bismuth Manganese Oxide Composite Ceramic For Optoelectronic Applications, P. P. Nayak, B. Swain, R. R. Patro, S. S. Hota, O. P. Das, S. Bhuyan Jan 2025

Comprehensive Study On The Structural And Optical Properties Of Bismuth Manganese Oxide Composite Ceramic For Optoelectronic Applications, P. P. Nayak, B. Swain, R. R. Patro, S. S. Hota, O. P. Das, S. Bhuyan

Journal of Metals, Materials and Minerals

This work assessed the potential of bismuth manganese oxide composite ceramic for optoelectronic applications by methodically examining its structural, vibrational, and optical characteristics. X-ray diffraction (XRD) spectroscopy provided the coexistence of Bi12MnO20 (sillenite-type) and Bi2Mn4O10 (mullite-type) phases, indicating a deviation from the ideal perovskite structure and suggesting a complex crystallographic nature influencing its functional properties. Fourier transform infrared (FTIR) spectroscopy confirmed the modes of vibration of Bi–O and Mn–O bonds that were contained, supporting the structural composition. UV-Vis-NIR spectroscopy demonstrated strong optical absorption in the 300 nm to 800 nm range, affirming the suitability of the material for optoelectronic applications. …

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Fem Modeling And Comparative Study Of Graphite Lubricants In The Hot Forging Of Aisi 1045 Medium Carbon Steel, Raschanan Poungprasert, Nattarawee Siripath, Naiyanut Jantepa, Surasak Suranuntchai Jan 2025

Fem Modeling And Comparative Study Of Graphite Lubricants In The Hot Forging Of Aisi 1045 Medium Carbon Steel, Raschanan Poungprasert, Nattarawee Siripath, Naiyanut Jantepa, Surasak Suranuntchai

Journal of Metals, Materials and Minerals

This study investigates the performance of water-based and oil-based graphite lubricants in the hot forging of AISI 1045 medium carbon steel, aiming to enhance product quality while minimizing die wear. Utilizing Finite Element Method (FEM) simulations and experimental analysis, we examined key factors including flow lines, dimensional accuracy, forging load, and die wear. Results indicate that oil-based graphite lubricants significantly outperform water-based options, achieving a lower average error of 0.26% in dimensional accuracy compared to 0.99% for water-based lubricants. Additionally, oil-based lubricants resulted in reduced forming loads, leading to improved energy efficiency and longer die life. Microstructural analysis revealed that …

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Effect Of Compaction Pressure On The Structure And Mechanical Properties Of Functionally Graded Aluminium-Glass Microsphere (Fgagm) Foams Produced By Powder Metallurgy Process, Vicheka Moeun, Seksak Asavavisithchai Jan 2025

Effect Of Compaction Pressure On The Structure And Mechanical Properties Of Functionally Graded Aluminium-Glass Microsphere (Fgagm) Foams Produced By Powder Metallurgy Process, Vicheka Moeun, Seksak Asavavisithchai

Journal of Metals, Materials and Minerals

Functionally graded aluminium-glass microsphere (FGAGM) foams were successfully fabricated via powder metallurgy. The influence of compaction pressure on the structural and mechanical properties of the foams was systematically investigated. The study observed that increasing compaction pressure enhanced the green (pre-sintering) density of FGAGM foam, while post-sintering densities exhibited a decreasing trend with higher compaction pressures. The mechanical examination indicated that mechanical properties improved significantly with higher compaction pressures. While higher compaction pressures generally improve mechanical properties, the study identified that excessive pressures could lead to the fracture of GM particles, introducing defects that compromise the foam's structural integrity. Therefore, determining …

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Structural Tuning Of Bioi Toward Bi O /Agi Heterostructures Via Room-Temperature Ion Exchange For Improved Photocatalytic Activity, Varunya Atimayulerd, Sorawit Thueanbangyang, Kittiyaporn Singsumphan, Ganyaporn Wongwaen, Cheewita Suwanchawalit, Montri Aiempanakit Jan 2025

Structural Tuning Of Bioi Toward Bi O /Agi Heterostructures Via Room-Temperature Ion Exchange For Improved Photocatalytic Activity, Varunya Atimayulerd, Sorawit Thueanbangyang, Kittiyaporn Singsumphan, Ganyaporn Wongwaen, Cheewita Suwanchawalit, Montri Aiempanakit

Journal of Metals, Materials and Minerals

In this work, a bismuth oxide/silver iodide (Bi2O3/AgI) heterojunction photocatalyst was successfully fabricated via a room-temperature ion exchange process using bismuth oxyiodide (BiOI) as a morphology-directing precursor. Building upon our previous work on solvent-modulated BiOI nanostructures, this study employs a chemical transformation route to develop interfacially connected heterostructures while preserving key morphological features. Structural, morphological, and optical characterizations, including X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and ultraviolet–visible diffuse reflectance spectroscopy, provided supporting evidence for the successful formation of Bi2O3/AgI heterojunctions with likely close interfacial contact. The optimized Bi2O3/AgI composite with a 50:50 mass ratio …

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Optically Stimulated Luminescence Dating Of Earthenware From The Nam Tok Khao Pang Archaeological Site, Kanchanaburi, Thailand, Thananan Phetkongtong, Peerasak Klubket, Santi Pailoplee, Pichet Limsuwan, Voranuch Thongpool Jan 2025

Optically Stimulated Luminescence Dating Of Earthenware From The Nam Tok Khao Pang Archaeological Site, Kanchanaburi, Thailand, Thananan Phetkongtong, Peerasak Klubket, Santi Pailoplee, Pichet Limsuwan, Voranuch Thongpool

Journal of Metals, Materials and Minerals

The Nam Tok Khao Pang archaeological site, located in Tha Sao subdistrict, Sai Yok district, Kanchanaburi province, Thailand, is a limestone cave where numerous artifacts, including black-burnished earthenware fragments with in-curving rims, out-curving rims, and carinated bodies, have been discovered. Mineralogical and microstructural analyses using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) identified quartz (SiO₂) as the dominant mineral phase within a partially sintered silicate matrix. The absence of vitrification and the presence of mineral impurities indicate that the earthenware was fired at temperatures between 900°C and 1000°C. To determine the age of these ceramics, …

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Facile Bio-Synthesis Of Cerium Oxide Nanoparticles, Characterization And Their Photocatalytic Potential In The Degradation Of Real Tannery Wastewater, Ganeshkumar Govindasamy, A. Babu Ponnusami Jan 2025

Facile Bio-Synthesis Of Cerium Oxide Nanoparticles, Characterization And Their Photocatalytic Potential In The Degradation Of Real Tannery Wastewater, Ganeshkumar Govindasamy, A. Babu Ponnusami

Journal of Metals, Materials and Minerals

The sustainable metal oxide photocatalysts using plant extract presents a viable alternative to conventional chemical synthesis techniques. In this study, spherical shaped cerium oxide nanoparticles were synthesized using ammonium ceric nitrate and Peepal Leaves (PL) extracted and used as a photocatalyst to remove hexavalent chromium and chemical oxygen demand from actual tannery wastewater. The characterization of cerium oxide nanoparticles was carried out using UV-Visible spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, Brunauer-Emmett-Teller surface area analysis, Field Emission-Scanning Electron Microscopy with energy-dispersive X-ray spectroscopy, Raman analysis, High Resolution-Transmission Electron Microscopy and Zeta potential analysis. The band gap energy of 3.25 eV was …

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Influence Of Deck Area And Average Daily Traffic On The Deterioration Of Bridge Superstructures., Faysal Ahamed Jan 2025

Influence Of Deck Area And Average Daily Traffic On The Deterioration Of Bridge Superstructures., Faysal Ahamed

Graduate Theses, Dissertations, and Problem Reports (ETD)

State Departments of Transportation (DOTs) are responsible for maintaining approximately 623,000 bridges across the United States. Effective bridge management requires a comprehensive understanding of the factors influencing structural deterioration. Numerous studies have explored the effects of average daily traffic (ADT) and deck area (DA) on bridge deck deterioration. Given the interdependence between bridge decks and superstructures, it is plausible that ADT and DA significantly influence superstructure condition ratings and deterioration trends. However, their impact on superstructures remains insufficiently studied. In addition, existing studies primarily focus on overall bridge deterioration without adequately differentiating between superstructure designs and materials and maintenance authorities. …

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Multitec: A Data-Driven Multimodal Short Video Detection Framework For Healthcare Misinformation On Tiktok, Lanyu Shang, Yang Zhang, Yawen Deng, Dong Wang Jan 2025

Multitec: A Data-Driven Multimodal Short Video Detection Framework For Healthcare Misinformation On Tiktok, Lanyu Shang, Yang Zhang, Yawen Deng, Dong Wang

Computer Science Faculty Works

With the prevalence of social media and short video sharing platforms (e.g., TikTok, YouTube Shorts), the proliferation of healthcare misinformation has become a widespread and concerning issue that threatens public health and undermines trust in mass media. This paper focuses on an important problem of detecting multimodal healthcare misinformation in short videos on TikTok. Our objective is to accurately identify misleading healthcare information that is jointly conveyed by the visual, audio, and textual content within the TikTok short videos. Three critical challenges exist in solving our problem: i) how to effectively extract information from distractive and manipulated visual content in …

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Development And Evaluation Of Machine Learning Models For Early Pediatric Sepsis Prediction, Ancita M. Andrade Jan 2025

Development And Evaluation Of Machine Learning Models For Early Pediatric Sepsis Prediction, Ancita M. Andrade

Browse all Theses and Dissertations

Sepsis is a leading cause of pediatric mortality, claiming more lives in the United States annually than all childhood cancers combined. Early identification in Emergency Departments (EDs) remains challenging, as the current Phoenix criteria establishes an updated international consensus definition for sepsis, however is not designed for use as a screening tool. This study aimed to develop predictive models identifying pediatric patients at risk of sepsis within 24 hours of admission. Multiple tree-based and deep learning models were trained utilizing clinical and laboratory data from the initial four hours of presentation. Both the LightGBM and LSTM architectures demonstrated superior performance, …

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Cellular Mechanisms Of Spinal Motoneuron Hypoexcitability Underlying Dynapenia In Aging, Ibrahim Abdul Halim Jan 2025

Cellular Mechanisms Of Spinal Motoneuron Hypoexcitability Underlying Dynapenia In Aging, Ibrahim Abdul Halim

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Age-related weakness remains poorly understood as the underlying mechanisms remain unclear. While synaptic input and muscular changes have been investigated with age, intrinsic motoneuron excitability alterations are often overlooked. This thesis provides the first direct assessment of intrinsic excitability and ion channel properties of spinal α-MNs from male and female mice across three ages: young, middle aged, and old. Our findings reveal a decline in intrinsic excitability of motoneurons with age in both sexes. Mechanistic analysis shows sex specific differences: female motoneurons exhibit increased dendritic size, hyperpolarized RMP, and SK channel overactivation, whereas males show only SK overactivation with age. …

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Wearable Sensor Data Analysis For Machine Learning-Based Detection Of Posture And Autonomic Responses, Chaitanya Vardhini Anumula Jan 2025

Wearable Sensor Data Analysis For Machine Learning-Based Detection Of Posture And Autonomic Responses, Chaitanya Vardhini Anumula

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This study investigates how Iyengar yoga postures influence autonomic nervous system (ANS) activity by analyzing multimodal physiological signals collected via wearable sensors. The physiological mechanisms underlying Iyengar yoga’s therapeutic effects remain under-explored at the granular, pose-level. Using data collected from 16 participants, this research evaluates whether machine learning models can distinguish between baseline, parasympathetic-dominant, and sympathetic-dominant states based on wrist-worn sensor data. The goals were to explore whether subtle postural variations elicit measurable autonomic responses and to identify which sensor features most effectively capture these changes. Participants performed a sequence of yoga poses while wearing synchronized sensors measuring electrodermal activity …

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Impact Of Graph Structures For Rag Outcomes In Llms, Chris Davis Jaldi Jan 2025

Impact Of Graph Structures For Rag Outcomes In Llms, Chris Davis Jaldi

Browse all Theses and Dissertations

Explainability, interpretability and adaptability (EIA) remain three central motivations for next-generation Artificial Intelligence (AI), especially as Large Language Models (LLMs) continue to engage with ever-increasing knowledge bodies. As the landscape pushes toward controllable agentic Retrieval-Augmented Generation (RAG) systems where AI agents engage in iterative, guided reasoning, a critical question arises as to the extent to which the knowledge design itself shapes these models' reasoning behavior. This work conducts a systematic evaluation of how different conceptualizations and representation of the identical knowledge affect an LLM's path-based reasoning capabilities. Through the introduction of controlled variations along graph structural complexity, linguistic and semantic …

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Re-Parameterizing Adversarial Reprogramming In Low-Dimensional Subspace For Efficient Software Vulnerability Detection, Hootan Alavizadeh Jan 2025

Re-Parameterizing Adversarial Reprogramming In Low-Dimensional Subspace For Efficient Software Vulnerability Detection, Hootan Alavizadeh

Browse all Theses and Dissertations

Software vulnerabilities are a major cause of security breaches, making effective detection critical. Traditional learning-based methods require large datasets and significant computational resources, which are often impractical due to high annotation costs and data scarcity. To address this, we propose an innovative system, RearVul, which Re-parameterizes adversarial reprogramming in a low-dimensional subspace for software vulnerability detection. Unlike conventional approaches, RearVul repurposes a pre-trained classification model using adversarial reprogramming, enabling detection with minimal modifications. It learns a universal perturbation applied to program representations, preserving the original model’s feature extraction capabilities while adapting it to a new domain. Furthermore, we introduce a …

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Subjective Readiness Forecasting Using Supervised Machine Learning And Wearable Device Data, Nathaniel Michael Weiland Jan 2025

Subjective Readiness Forecasting Using Supervised Machine Learning And Wearable Device Data, Nathaniel Michael Weiland

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Recent advances in wearable technology allow continuous monitoring of physiological and behavioral data, opening new opportunities for real-time assessments of readiness and well-being. However, creating predictive models that generalize across diverse users remains challenging, especially in high-stakes settings like the military, where preventable injuries, illnesses, and stress-related performance declines are frequent. This research assesses the feasibility of using supervised machine learning models trained on wearable device data to predict subjective readiness indicators—recovery, stress, injury, and illness. Data from over 10,000 users in the OHWS (Optimizing the Human Weapons System) program combined daily check ins with physiological metrics from Garmin, Polar, …

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Computational Assessment Of Vitrimers Self-Healing For Renewable Energy And Aerospace Structures, Walaaeldin Mohamed Ahmed Derbala Jan 2025

Computational Assessment Of Vitrimers Self-Healing For Renewable Energy And Aerospace Structures, Walaaeldin Mohamed Ahmed Derbala

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Self-healing polymers, particularly vitrimers, are emerging as promising candidates in the development of advanced materials for renewable energy and aerospace structures. These materials exhibit dynamic covalent bond exchange mechanisms that enable reprocess ability, damage repair, and extended operational lifetime under harsh conditions. This study presents a density functional theory (DFT)-based computational investigation of the mechanistic pathways and energetics of bond exchange reactions in model vitrimer systems. We explore transition states, energy barriers, and thermodynamic features corresponding to associative and dissociative self-healing reactions in vitrimers. The study focuses on Diaminodiphenyl disulfide (AFD), a bifunctional molecule composed of two para-substituted aminophenyl rings …

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Ab Initio Simulations For Oxidation Of An Ultra-High Temperature Ceramic (Hfb2), Wesley I. Black Jan 2025

Ab Initio Simulations For Oxidation Of An Ultra-High Temperature Ceramic (Hfb2), Wesley I. Black

Browse all Theses and Dissertations

Ultra-High Temperature Ceramics are a class of ceramics that possess high strength and melting points in excess of 3000°C. These ceramics are promising for aerospace applications, where materials need to endure high-temperature and high-stress environments. Utilizing ab initio simulations, this thesis research focuses on the atomistic details of oxidation for a typical ultra-high temperature ceramic material, namely hafnium diboride. The simulations provide energy barriers for transition from the initial to final structures via transition states on the (0 0 0 1) surface. These result in estimates for reaction rates and other thermodynamic features that are essential for assessing applicability under …

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Reinforcement Learning For Adversarial Environments: Multi-Agent Hide And Seek With Multi-Modal Sensing, Christian Alejandro Carrizales Jan 2025

Reinforcement Learning For Adversarial Environments: Multi-Agent Hide And Seek With Multi-Modal Sensing, Christian Alejandro Carrizales

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The development of intelligent and competitive agents in AI versus AI adversarial environments was explored through the utilization of reinforcement learning techniques with sensing modalities. A Hide-and-Seek simulation environment was developed using the Unity game engine along with the ML-Agents Toolkit. An engagement test campaign with a set of performance metrics was designed. Four AI versus AI adversarial scenarios were considered using the Proximal Policy Optimization (PPO) and Soft Actor-Critic (SAC) multi-agent reinforcement learning algorithms. Furthermore, the impact of sensing modalities on competing agents’ learning performance was investigated by varying the sensing capabilities of the hider and seeker, respectively. Experiments …

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Dataset Generation For Routing Policy Study In Ad Hoc Wireless Networks, Vishnu Vishnu Priya Jan 2025

Dataset Generation For Routing Policy Study In Ad Hoc Wireless Networks, Vishnu Vishnu Priya

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Ad Hoc wireless networks, with their decentralized architecture and dynamic topology, present challenges in reliable and energy-efficient routing. While machine learning (ML) and reinforcement learning (RL) offer promising solutions, progress is limited by the lack of realistic, high-fidelity datasets. This research introduces a simulation-based framework for generating four diverse datasets representing combinations of node mobility (mobile vs. static) and spatial distribution (random vs. clustered). Each dataset captures critical metrics such as Signal-to-Interference-plus-Noise Ratio (SINR), bottleneck rate, and power consumption across multi-hop paths. A lookahead-based greedy routing algorithm with scenario-aware power control is implemented to emulate practical behavior. Supervised ML models, …

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Isometric Centroid Encoder (Ice) And Synthetic Data Generation Approaches For Biological Datasets, Prathyusha Kanakamalla Jan 2025

Isometric Centroid Encoder (Ice) And Synthetic Data Generation Approaches For Biological Datasets, Prathyusha Kanakamalla

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This thesis addressed two main challenges in biological data analysis: structure-preserving dimensionality reduction and synthetic data generation for small sample datasets. I proposed the Isometric Centroid Encoder (ICE), a supervised dimensionality reduction method that preserves pairwise distances between class centroids during dimension reduction. Unlike existing methods like Centroid Encoder and Super Encoder, ICE explicitly maintains geometric relationships between biological classes, achieving nearly perfect structure preservation at C dimensions (where C equals the number of classes) with strong performance even in 2D and 3D spaces. Additionally, I compared three generative models (VAE, LSH-GAN, and scDiffusion) for synthetic data generation on small …

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Hydrogen Storage Density And Adsorption Energy Barriers On Li-Decorated Bc3 Nanosheet, Sri Venkat Pavan Upasi Jan 2025

Hydrogen Storage Density And Adsorption Energy Barriers On Li-Decorated Bc3 Nanosheet, Sri Venkat Pavan Upasi

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Hydrogen is considered an emerging carrier of clean energy with renewable capabilities. Widespread hydrogen energy utilization necessitates efficient storage strategies. Functionalized nanomaterials, such as Li-decorated BC3 nanosheets, are among the primary candidate materials for hydrogen storage. This research investigates the feasibility of hydrogen storage by estimating energy barriers and their dependence on storage density on Li-decorated BC3 nanosheet. Density functional theory (DFT) simulations provide estimates of adsorption energies and saddle points for hydrogen storage and compare corresponding reaction rates. The results are expected to help us understand the advantages and possible shortcomings of hydrogen storage on such nanomaterials.

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