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Articles 3451 - 3480 of 16790

Full-Text Articles in Materials Science and Engineering

Development Of Advanced Germanium Detectors For Rare Event Physics, Sanjay Bhattarai Jan 2023

Development Of Advanced Germanium Detectors For Rare Event Physics, Sanjay Bhattarai

Dissertations and Theses

High Purity Germanium (HPGe) detectors are widely used in rare-event physics searches for dark matter, neutrinoless double-beta decay, and solar neutrinos. This dissertation fo- cuses on improving crystal quality by controlling the impurity concentration, dislocation density, and growth environment as well as developing advanced Ge detectors for various physics applications. The dissertation presents experimental investigations of electrical conduction mechanisms in p-type amorphous germanium (a-Ge), which is used as an elec- trical contact material in HPGe detectors. By measuring the surface leakage current from three high-purity planar Ge detectors, we determine the localization length and hopping parameters in a-Ge. The dissertation …

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A Thermal, Mechanical, And Materials Framework For A Shape Memory Alloy Heat Engine For Thermal Management And Energy Recovery, Maria Chikhareva Jan 2023

A Thermal, Mechanical, And Materials Framework For A Shape Memory Alloy Heat Engine For Thermal Management And Energy Recovery, Maria Chikhareva

Electronic Theses and Dissertations, 2020-2023

Shape memory alloy (SMA) heat engines possess an inherent property of sensing a change in temperature, performing work, and rejecting heat through the shape memory effect resulting from a temperature-induced phase transformation. This work presents a framework for the design and implementation of an SMA-based Stirling heat engine for maximum power or speed incorporating and combining mechanical, thermal, and material aspects. The motivation for this work comes from the growing need for reliable thermal management and energy recovery in both ground and space applications of interest to NASA and commercial space companies. In future lunar and Mars missions, an SMA …

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Investigation Of Fiber Orientation And Mechanical Properties Of Pyrolysis Recycled Carbon-Fiber Reinforced Thermoset Composite, Reva N. Simmons, Harry Lee, Garam Kim Jan 2023

Investigation Of Fiber Orientation And Mechanical Properties Of Pyrolysis Recycled Carbon-Fiber Reinforced Thermoset Composite, Reva N. Simmons, Harry Lee, Garam Kim

Discovery Undergraduate Interdisciplinary Research Internship

With increasing demand of carbon fiber reinforced fiber thermoset composites, establishing a sustainable cycle for these materials becomes crucial. Pyrolysis is a process of reclaiming carbon fiber from thermoset composites by thermally degrading the polymer at high temperatures allowing the fibers to be extracted. Carbon fiber reclaimed through current pyrolysis processes for thermoset composites typically loses its original shape and orientation, making it difficult to reorganize the fibers. This study investigated the feasibility of maintaining the fiber orientations for continuous fiber reinforced thermoset composite during pyrolysis by stitching the carbon fiber layup to a conformable copper mesh during the manufacturing …

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Laser Powder Bed Fusion Of Bimetallic Structures, Asif Mahmud Jan 2023

Laser Powder Bed Fusion Of Bimetallic Structures, Asif Mahmud

Graduate Thesis and Dissertation 2023-2024

Laser powder bed fusion (LPBF) is a popular additive manufacturing (AM) technique that has demonstrated the capability to produce sophisticated engineering components. This work reports the crack-free fabrication of an SS316L/IN718 bimetallic structure via LPBF, along with compositional redistribution, phase transformations and microstructural development, and nanohardness variations. Constituent intermixing after LPBF was quantitatively estimated using thermo-kinetic coefficients of mass transport and compared with the diffusivity of Ni in the austenitic Fe-Ni system. The intermixing of primary solvents (Ni and Fe) in SS316L/IN718 bimetallic structures was observed for an intermixing zone of approximately 800 µm, and their intermixing coefficient was estimated …

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Exposure To Pcb126 During The Nursing Period Reversibly Impacts Early-Life Glucose Tolerance, Brittany B. Rice, Keegan W. Sammons, Sara Y. Ngo Tenlep, Madeline T. Weltzer, Leryn J. Reynolds, Cetewayo S. Rashid, Hollie I. Swanson, Kevin J. Pearson Jan 2023

Exposure To Pcb126 During The Nursing Period Reversibly Impacts Early-Life Glucose Tolerance, Brittany B. Rice, Keegan W. Sammons, Sara Y. Ngo Tenlep, Madeline T. Weltzer, Leryn J. Reynolds, Cetewayo S. Rashid, Hollie I. Swanson, Kevin J. Pearson

Human Movement Studies & Special Education Faculty Publications

Polychlorinated biphenyls (PCBs) are persistent environmental organic pollutants known to have detrimental health effects. Using a mouse model, we previously demonstrated that PCB126 exposure before and during pregnancy and throughout the perinatal period adversely affected offspring glucose tolerance and/or body composition profiles. The purpose of this study was to investigate the glucose tolerance and body composition of offspring born to dams exposed to PCB126 during the nursing period only. Female ICR mice were bred, and half of the dams were exposed to either vehicle (safflower oil) or 1 µmole PCB126 per kg of body weight via oral gavage on postnatal …

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Nanostructured Alloy Thin Film Fabrication And Application For Zinc-Air Battery And Lithium-Ion Battery, Guanzhi Wang Jan 2023

Nanostructured Alloy Thin Film Fabrication And Application For Zinc-Air Battery And Lithium-Ion Battery, Guanzhi Wang

Electronic Theses and Dissertations, 2020-2023

The depletion of unsustainable fossil fuels and growing environmental issues have given rise to scientific challenges and research interests in the development of renewable energy technologies to meet the rising global energy demand. Electrochemical energy storage and conversion technologies (ESCTs), such as lithium-ion batteries, metal-air batteries, supercapacitors, and fuel cells, etc., offer a clean and sustainable strategy for utilizing energy. As the core components, the electrode materials, including anodes, cathodes, and catalysts, play a direct decisive role in the device's performance in practical application. Therefore, the development of high-performance and low-cost electrode materials is critical for the success of these …

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Electroanalytical Investigations Of Microrna-Conjugated Cerium Oxide Based Nanomaterials For Biomedical Applications, Chaimae El Ghzaoui Jan 2023

Electroanalytical Investigations Of Microrna-Conjugated Cerium Oxide Based Nanomaterials For Biomedical Applications, Chaimae El Ghzaoui

Electronic Theses and Dissertations, 2020-2023

Diabetes patients are increasingly suffering from wound-healing impairments coupled with other severe medical conditions. High levels of oxidative stress and proinflammatory cytokines are predominant pathologic characteristics of diabetic wounds. Applying microRNA (miRNA) in gene therapy often successfully treats various disorders by generating highly specific bio-responses. Studies revealed that microRNA146a (miR146a), a regulator of inflammation, is downregulated in diabetic wounds. However, miR203 is found to be highly-expressed in diabetic foot ulcers in positive correlation with disease severity. We have synthesized Cerium oxide nanoparticles (CNPs) since they are used in various biomedical applications due to their high enzyme-mimetic activities and reactive oxygen …

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Intragranular Tungsten-Titanium Carbide Composite Ceramics Via Gas-Solid Displacement Reactions, Ryan Daniel Dempsey Jan 2023

Intragranular Tungsten-Titanium Carbide Composite Ceramics Via Gas-Solid Displacement Reactions, Ryan Daniel Dempsey

Doctoral Dissertations

"Research presented herein details the synthesis and characterization of nanocomposite ceramics featuring novel heterogeneous microstructures of potential interest in a variety of electrical and structural applications. Specifically, W-TiCy composite ceramics featuring tungsten nanoprecipitates located primarily within TiCy grains have been produced via sintering of intragranular nanocomposite powders produced via reaction processing-based techniques. This dissertation details the thermodynamic basis and applied kinetics of a processing scheme for fabricating nanocomposite ceramics whose morphological heterogeneity reflects that originally developed in the powder state. The first study in this series overviews the motivation for applying metallothermic displacement reactions, conducted through gaseous intermediates, to solid …

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Phosphate And Borophosphate Glasses For Optical And Biomedical Applications, Parker Tracy Freudenberger Jan 2023

Phosphate And Borophosphate Glasses For Optical And Biomedical Applications, Parker Tracy Freudenberger

Doctoral Dissertations

"The goal of this work was to connect the network structures of phosphate and borophosphate glasses to the compositional dependence of properties related to biomedical applications. The glasses were characterized by a variety of techniques, including phosphate ion chromatography, Raman spectroscopy, and 11B and 31P Magic Angle Spinning Nuclear Magnetic Resonance spectroscopy, which provide qualitative and quantitative information about the phosphate and borate moieties that constitute the network structures. The systematic addition of borate to a phosphate glass initially creates tetrahedral borate sites that replace P-O-P linkages with B-O-P linkages, and the properties of the resulting borophosphate glasses …

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Size Distribution, Elemental Composition And Morphology Of Nanoparticles Separated From Respirable Coal Mine Dust, Shoeleh Assemi, Lei Pan, Xuming Wang, Titilayo Akinseye, Jan D. Miller Jan 2023

Size Distribution, Elemental Composition And Morphology Of Nanoparticles Separated From Respirable Coal Mine Dust, Shoeleh Assemi, Lei Pan, Xuming Wang, Titilayo Akinseye, Jan D. Miller

Michigan Tech Publications, Part 1

Nanoparticles, defined as particles with one dimension below 100 nm, contribute little to the total mass concentration in respirable coal mine dust (RCMD) toxicological studies, but they could have a considerable part in the adverse health effects by RCMD inhalation. It has been shown that inhaled nanoparticles can penetrate deep into the lung and could plausibly contribute to acute and chronic pulmonary diseases by triggering oxidative stress formation and inducing inflammation. RCMD nanoparticles from samples collected in an underground mine in the United States were analyzed by a particle separation technique, field-flow fractionation (FFF), for size, morphology, and elemental composition. …

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Temperature Monitoring In The Refractory Lining Of A Continuous Casting Tundish Using Distributed Optical Fiber Sensors, Muhammad Roman, Hanok Tekle, Dinesh Reddy Alla, Farhan Mumtaz, Jeffrey D. Smith, Laura Bartlett, Ronald J. O'Malley, Rex E. Gerald, Jie Huang Jan 2023

Temperature Monitoring In The Refractory Lining Of A Continuous Casting Tundish Using Distributed Optical Fiber Sensors, Muhammad Roman, Hanok Tekle, Dinesh Reddy Alla, Farhan Mumtaz, Jeffrey D. Smith, Laura Bartlett, Ronald J. O'Malley, Rex E. Gerald, Jie Huang

Materials Science and Engineering Faculty Research & Creative Works

This Article Explores the Prospects of using Spatially Distributed Optical Fiber Temperature Sensors based on Rayleigh Optical Frequency Domain Reflectometry (OFDR) Technology in the Continuous Casting of Molten Steel. the Measurement Capability of the Optical Fiber Sensors in a Simulated Steelmaking Environment Was Demonstrated using a Mock Refractory-Lined Tundish, Which Was Fabricated In-House. Single-Mode Optical Fibers, Contained in Protective Stainless-Steel Tubing, Were Embedded in the Refractory Lining of the Mock Tundish. the Instrumented Tundish Was Preheated Up to a Temperature of 960 °C (Recorded at the Surface of the Working Lining) Before the Molten Steel Pour. a Low-Alloy Steel (AISI …

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Constructing A Fine Dispersion And Chemical Interface Based On An Electrostatic Self-Assembly And Aqueous Phase Compound In Go/Sio2/Sbr Composites To Achieve High-Wear Resistance In Eco-Friendly Green Tires, Rui Zhang, Jiaye Li, Stephen Jerrams, Shui Hu, Shipeng Wen, Ligun Zhang Jan 2023

Constructing A Fine Dispersion And Chemical Interface Based On An Electrostatic Self-Assembly And Aqueous Phase Compound In Go/Sio2/Sbr Composites To Achieve High-Wear Resistance In Eco-Friendly Green Tires, Rui Zhang, Jiaye Li, Stephen Jerrams, Shui Hu, Shipeng Wen, Ligun Zhang

Articles

The hazard to the ecosystem caused by rubber microparticles generated from tire abrasion has been a constant concern. Therefore, to protect this ecosystem, the development of a tire tread with high abrasion resistance is especially significant. Herein, γ-aminopropyltriethoxysilane (APTES) was used to modify graphene oxide (GO) and silica (SiO2) to obtain GO and SiO2 with positive charges (NG and NS). Furthermore, NG and NS were electrostatically self-assembled by using maleic anhydride (MAH) hydrolysis, thereby obtaining composite particles (NG-NS) with “bridged structures”. Also, the NG-NS/styrene butadiene rubber (SBR) compounds possessing fine dispersion of NG-NS were prepared by the aqueous compounding method. …

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Hydrogen-Wettability Alteration Of Indiana Limestone In The Presence Of Organic Acids And Nanofluid, Mirhasan Hosseini, Rossen Sedev, Mujahid Ali, Muhammad Ali, Jalal Fahimpour, Alireza Keshavarz, Sefan Iglauer Jan 2023

Hydrogen-Wettability Alteration Of Indiana Limestone In The Presence Of Organic Acids And Nanofluid, Mirhasan Hosseini, Rossen Sedev, Mujahid Ali, Muhammad Ali, Jalal Fahimpour, Alireza Keshavarz, Sefan Iglauer

Research outputs 2022 to 2026

This study focuses on the wettability alteration (changing from a hydrophobic state to a hydrophilic state) of Indiana limestone for hydrogen (H2) geological storage. We examine the effect of hexanoic acid C6, lauric acid C12, and stearic acid C18, on the wettability of Indiana limestone at ambient (298 K and 0.1 MPa) and reservoir (323 K and 8.27 MPa) conditions. The effects of silica nanofluids (silica with deionized water) at various concentrations (0.1 wt%, 0.25 wt%, and 0.5 wt%) on the wettability reversal of stearic-aged samples were tested at ambient and reservoir …

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Effect Of Mechanical Activation On Carbothermal Synthesis And Densification Of Zrc, Nina Obradović, Lun Feng, Suzana Filipović, Miljana Mirković, Darko Kosanović, Jelena Rogan, William Fahrenholtz Jan 2023

Effect Of Mechanical Activation On Carbothermal Synthesis And Densification Of Zrc, Nina Obradović, Lun Feng, Suzana Filipović, Miljana Mirković, Darko Kosanović, Jelena Rogan, William Fahrenholtz

Materials Science and Engineering Faculty Research & Creative Works

Zirconium carbide ceramics were prepared by carbothermal reduction of ZrO2 and C that were mixed by high-energy ball milling. Powders were milled for times from 0 to 120 min in air. As milling time increased, the surface area of the powders increased, indicating significant particle size reduction. Milled powders were reacted at 1600 °C and then densified by spark plasma sintering at 2000 °C, which was sufficient to convert the starting powders to zirconium carbide. Unmilled powders did not reach full density. Milled powders reached full density, but ZrO2 impurities were found for specimens prepared from powders milled …

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Effect Of Annealing Time On Texture Evolution Of Fe–3.4 Wt% Si Nonoriented Electrical Steel, Yizhou Du, Ronald J. O'Malley, Mario F. Buchely, Paul Kelly Jan 2023

Effect Of Annealing Time On Texture Evolution Of Fe–3.4 Wt% Si Nonoriented Electrical Steel, Yizhou Du, Ronald J. O'Malley, Mario F. Buchely, Paul Kelly

Materials Science and Engineering Faculty Research & Creative Works

Herein, the Effect of Annealing Time on the Texture Evolution in Fe–3.4 Wt.% Si Non-Oriented Electrical Steel is Investigated. Strip Samples Are Cast using a Vacuum Sampling Method, Which Simulate the Solidification Conditions of an Industrial Twin Roll Thin Strip Casting (TRSC) Process. As-Cast Samples with Different Carbon and Sulfur (C&S) Levels Are Hot Rolled (HR) with Varying Levels of Hot Deformation, Cold Rolled (CR) to 0.35 Mm Thickness, and Then Annealed at 1050 °C for Different Holding Times (1, 6, 24 H). to Fe–3.4 Wt.% Si Non oriented Electrical Steel, the Observed Texture Evolution Can Be Divided into Different …

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Advancing Aluminum Casting Optimization With Real-Time Temperature And Gap Measurements Using Optical Fiber Sensors At The Metal-Mold Interface, Bohong Zhang, Abhishek Prakash Hungund, Dinesh Reddy Alla, Deva Prasaad Neelakandan, Muhammad Roman, Ronald J. O'Malley, Laura Bartlett, Rex E. Gerald, Jie Huang Jan 2023

Advancing Aluminum Casting Optimization With Real-Time Temperature And Gap Measurements Using Optical Fiber Sensors At The Metal-Mold Interface, Bohong Zhang, Abhishek Prakash Hungund, Dinesh Reddy Alla, Deva Prasaad Neelakandan, Muhammad Roman, Ronald J. O'Malley, Laura Bartlett, Rex E. Gerald, Jie Huang

Materials Science and Engineering Faculty Research & Creative Works

Accurate measurement of interfacial heat transfer during casting solidification is crucial for optimizing metal solidification processes. The gap between the mold wall and the casting surface plays a significant role in heat transfer and cooling rates. In this study, two innovative fiber-optic sensors are employed to measure real-time mold gaps and thermal profiles during the solidification of A356 aluminum in a permanent mold casting. The experimental setup consists of a specially designed mold system made of unheated, uncoated tool steel, which facilitates easy installation of the fiber-optic sensors. An Extrinsic Fabry-Perot interferometric (EFPI) sensor is utilized to monitor the evolving …

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Microstructure Evolution And Austenitic Grain Refinement Of Ti-Modified High Mn Steels During Solution Annealing Heat Treatment, Abhinav Karanam, Arnab Sarkar, Erik Nenzen, Viraj Ashok Athavale, Mark Watson, Laura Nicole Bartlett, Lukas Bichler Jan 2023

Microstructure Evolution And Austenitic Grain Refinement Of Ti-Modified High Mn Steels During Solution Annealing Heat Treatment, Abhinav Karanam, Arnab Sarkar, Erik Nenzen, Viraj Ashok Athavale, Mark Watson, Laura Nicole Bartlett, Lukas Bichler

Materials Science and Engineering Faculty Research & Creative Works

Austenitic high manganese (Mn) steels are often used in harsh environments due to their high toughness and wear resistance. Heat treatments are performed to engineer the microstructure of the steels and optimize their performance for the desired service conditions. This study investigated the effect of titanium (Ti) and heat treatment on the microstructure of cast high Mn steel (HMS) alloys. The results reveal that Ti addition contributed to grain refinement in the as cast and heat-treated conditions. In-situ observation of microstructure evolution up to 1125 °C confirmed the stability of precipitated TiC particles, while revealing a new mechanism of grain …

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In Situ High-Temperature Raman Spectroscopy Via A Remote Fiber-Optic Raman Probe, Bohong Zhang, Hanok Tekle, Ronald J. O'Malley, Jeffrey D. Smith, Rex E. Gerald, Jie Huang Jan 2023

In Situ High-Temperature Raman Spectroscopy Via A Remote Fiber-Optic Raman Probe, Bohong Zhang, Hanok Tekle, Ronald J. O'Malley, Jeffrey D. Smith, Rex E. Gerald, Jie Huang

Materials Science and Engineering Faculty Research & Creative Works

This Study Demonstrated for the First Time an in Situ High-Temperature Fiber-Optic Raman Probe to Study the Structure of Glass and Slag Samples at Temperatures Up to 1400 °C. a Customized External Telescope Was Integrated into a Portable Fiber-Optic Raman Probe to Extend the Optical Working Distance to Allow the Probe to Work in a High-Temperature Environment. Three Samples Were Evaluated to Demonstrate the Functionality of the High-Temperature Fiber-Optic Raman Probe. Room Temperature and High-Temperature Raman Spectra Were Successfully Collected and Analyzed. in Addition, a Deconvolution Algorithm Was Used to Identify Peaks in the Spectrum that Could Then Be Related …

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High Temperature Confocal Scanning Laser Microscopy Analysis Of Dead-Burned Magnesia Aggregates, Tyler Richards, Viraj Athavale, Jeffrey D. Smith, Ronald J. O'Malley Jan 2023

High Temperature Confocal Scanning Laser Microscopy Analysis Of Dead-Burned Magnesia Aggregates, Tyler Richards, Viraj Athavale, Jeffrey D. Smith, Ronald J. O'Malley

Materials Science and Engineering Faculty Research & Creative Works

Dead-Burned Magnesia is a Commonly Used Material in the Manufacturing of Refractories for the Steelmaking Industry. Aggregates of Dead-Burned Magnesia Contain Secondary Phases Due to the Impurities within the Magnesite Rock Used in its Production. While These Phases Can Aid in Sintering Magnesia, They May Have Some Impact on the High-Temperature Performance of the Refractory Product. High-Temperature Confocal Scanning Laser Microscopy Was Utilized to Observe the Behavior of Dead-Burned Magnesia Aggregates at Elevated Temperatures (Up to 1550°C). Liquid Formation Was Detected Even at Temperatures Below 1350°C. in Some Cases, This Liquid Quickly Exuded from the Aggregate Surface. This Liquid Phase …

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Additive Manufacturing Of Sic-Sialon Refractory With Excellent Properties By Direct Ink Writing, Ruoyu Chen, Saisai Li, Xinxin Jin, Haiming Wen Jan 2023

Additive Manufacturing Of Sic-Sialon Refractory With Excellent Properties By Direct Ink Writing, Ruoyu Chen, Saisai Li, Xinxin Jin, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

Additive manufacturing of SiC-Sialon refractory with complex geometries was achieved using direct ink writing processes, followed by pressure less sintering under nitrogen. The effects of particle size of SiC powders, solid content of slurries and additives on the rheology, thixotropy and viscoelasticity of ceramic slurries were investigated. The optimal slurry with a high solid content was composed of 81 wt% SiC (3.5 µm+0.65 µm), Al2O3 and SiO2 powders, 0.2 wt% dispersant, and 2.8 wt% binder. Furthermore, the accuracy of the structure of specimens was improved via adjustment of the printing parameters, including nozzle size, extrusion pressure, and layer height. The …

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Reduction Of Iron-Ore Pellets Using Different Gas Mixtures And Temperatures, Yuri Korobeinikov, Amogh Meshram, Christopher Harris, Olexandr Kovtun, Joe Govro, Ronald J. O'Malley, Olena Volkova, Seetharaman Sridhar Jan 2023

Reduction Of Iron-Ore Pellets Using Different Gas Mixtures And Temperatures, Yuri Korobeinikov, Amogh Meshram, Christopher Harris, Olexandr Kovtun, Joe Govro, Ronald J. O'Malley, Olena Volkova, Seetharaman Sridhar

Materials Science and Engineering Faculty Research & Creative Works

Direct reduction of iron ore (DRI) is gaining an increased attention due to the growing need to decarbonize industrial processes. The current industrial DRI processes are performed using reformed natural gas, which results in CO2 emission, although it is less than carbothermic reduction in the blast furnace. Carbon-free reduction may be realized through the utilization of green H2 as a reducing agent, in place of natural gas. Herein, the effects of various gas mixtures and temperature on the reduction kinetics of the hematite iron-ore pellets are focused on in this work. Pellets are reduced at 700, 800, 850, …

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Development Of Interatomic Potential Of High Entropy Diborides With Artificial Intelligence Approach To Simulate The Thermo-Mechanical Properties, Nur Aziz Octoviawan Jan 2023

Development Of Interatomic Potential Of High Entropy Diborides With Artificial Intelligence Approach To Simulate The Thermo-Mechanical Properties, Nur Aziz Octoviawan

Graduate Theses/Dissertations

The interatomic potentials designed for binary/high entropy diborides and ultra-high temperature composites (UHTC) have been developed through the implementation of deep neural network (DNN) algorithms. These algorithms employed two different approaches and corresponding codes; 1) strictly local & invariant scalar-based descriptors as implemented in the DEEPMD code and 2) equivariant tensor-based descriptors as included in the ALLEGRO code. The samples for training and validation sets of the forces, energy, and virial data were obtained from the ab-initio molecular dynamics (AIMD) simulations and Density Functional Theory (DFT) calculations, including the simulation data from the ultra-high temperature region (> 2000K). The study …

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Machine Learning Strategies For Potential Development In High-Entropy Driven Nickel-Based Superalloys, Marium Mostafiz Mou Jan 2023

Machine Learning Strategies For Potential Development In High-Entropy Driven Nickel-Based Superalloys, Marium Mostafiz Mou

Graduate Theses/Dissertations

In this study, I developed Deep Learning interatomic potentials to model a multi-phase and multi-component system of Ni-based Superalloys. The system has up to three major phase constituents, namely Gamma, Gamma Prime, and Transition-metal rich Carbide. I utilized invariant scalar-based and/or equivariant, tensor-based neural network (NN) approach as implemented in DEEPMD, NEQUIP/ALLEGRO codes, respectively, and Moment Tensor Potential (MTP). For the training and validation sets, I employed the ab-initio molecular dynamics (AIMD) trajectory results and ground state DFT calculations, including the energy, force, and virial database from highly diverse compositions, temperatures, and pressures following a “High Entropy Strategy.” The Deep …

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Defect State Study And Surface Patching In Zno Nanoparticles Via Nano- Bio Interaction With Dna Bases, Ummay Honey Jan 2023

Defect State Study And Surface Patching In Zno Nanoparticles Via Nano- Bio Interaction With Dna Bases, Ummay Honey

Graduate Theses/Dissertations

First, this thesis investigates the structural and optical properties of hydrothermally synthesized ZnO nanostructures, focusing on the effects of varying annealing temperatures on their properties. Structural characterizations using micro-Raman spectroscopy, X-ray diffraction (XRD), and morphological study called scanning electronic microscopy (SEM) show changes in crystallinity and intensity with different annealing temperatures. Optoelectronic characterization using photoluminescence spectroscopy reveals changes in luminescence properties near the ultraviolet region with temperature variation and in the visible emission area region. These results provide insights into how annealing temperature can affect the surface layer of ZnO nanostructures and can be applied to improve performance in electronic …

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A Study Of Synthesis And Characterization Of Naxmno2-Δ As A Cathode Material For Sodium-Ion Battery, Zia Uddin Mahmud Jan 2023

A Study Of Synthesis And Characterization Of Naxmno2-Δ As A Cathode Material For Sodium-Ion Battery, Zia Uddin Mahmud

Graduate Theses/Dissertations

The proliferation of renewable energy sources and the promising market for net-scale battery applications immediately increases the need for electrochemical energy storage technology. Sodium (Na) components are more accessible and less expensive than lithium. Being a sodium-based material with a high-power density provided by Na-ion diffusion, NaxMnO2- δ is a strong contender for large-scale Sodium-ion-battery (SIB) applications. In the current study, NaxMnO2- δ is created using a solid-state reaction technique, and investigated structural, electrical, and electrochemical properties of materials were investigated using X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), UV-VIS spectroscopy, and …

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Synthesis And Characterization Of Cage-Structured Compounds As Promising Thermoelectric Materials, Nusrat Yasmin Jan 2023

Synthesis And Characterization Of Cage-Structured Compounds As Promising Thermoelectric Materials, Nusrat Yasmin

Graduate Theses/Dissertations

The development of new thermoelectric materials is of great interest due to their potential to convert waste heat into useful electricity. The primary problem is that the physical factors that are utilized to assess thermoelectric performance conflict with one another. One way to improve their performance is to hinder the lattice from conducting heat through its vibrations while maintaining the heat conduction via the electrons. This can be done by creating cage structures that allow heavy atoms to jiggle. In this study, we report the synthesis of a group of such compounds, using the self-flux method. They all belong to …

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Modification Of Natural Fibrous Materials For Sar-Cov-2 Diagnostic And Ph-Simulated Theranostic Applications, Pornchanok Punnoy Jan 2023

Modification Of Natural Fibrous Materials For Sar-Cov-2 Diagnostic And Ph-Simulated Theranostic Applications, Pornchanok Punnoy

Chulalongkorn University Theses and Dissertations (Chula ETD)

This dissertation investigates the development of colorimetric sensors utilizing natural fibrous materials modified by nanomaterials to enhance the performance of chemical sensors and theranostic devices for healthcare applications. The work is divided into two main sections. The first section, cellulose is utilized as a dual-function platform for qualitative screening of SAR-CoV-2 for COVID-19 diagnosis by colorimetric sensor and quantitative detection by mass spectrometry. The cellulose is modified with gold nanoparticles conjugated to monoclonal antibodies, enabling the specific detection of viral protein antigens through colorimetric changes resulting from nanoparticle aggregation. This platform demonstrates a detection range from 0.01 to 1 µg·mL−1 …

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อิทธิพลของการเติมแมงกานีสต่อสมบัติทางไฟฟ้าและแม่เหล็กของเพอรอฟสไกต์ออกไซด์เอนโทรปีสูง, พีระพัศ เมลืองศิลป์ Jan 2023

อิทธิพลของการเติมแมงกานีสต่อสมบัติทางไฟฟ้าและแม่เหล็กของเพอรอฟสไกต์ออกไซด์เอนโทรปีสูง, พีระพัศ เมลืองศิลป์

Chulalongkorn University Theses and Dissertations (Chula ETD)

ในงานวิจัยนี้ได้ศึกษาผลของการเจือแมงกานีสเข้าไปในตำแหน่งบีของเซรามิกเพอรอฟสไกต์เอนโทรปีสูง (Na0.2Bi0.2Ba0.2Sr0.2Ca0.2)Ti1-xMnxO3 (NBBSCT) ต่อสมบัติทางด้านไฟฟ้าและแม่เหล็ก โดยเจือแมงกานีสที่ความเข้นข้น x เท่ากับ 0, 0.05, 0.10, 0.15 และ 0.20 การเตรียมผงเซรามิกนั้นเตรียมด้วยวิธีปฎิกิริยาสถานะของแข็งซึ่งเผาแคลไซน์ที่อุณหภูมิ 975 องศาเซลเซียส เป็นระยะเวลา 1 ชั่วโมงด้วยอัตราการให้ความร้อน 5 องศาเซลเซียสต่อนาที และทำการเผาผนึกภายในถ้วยอะลูมินาที่อุณหภูมิ 1275 องศาเซลเซียส เป็นระยะเวลา 2 ชั่วโมงด้วยอัตราการให้ความร้อน 2 องศาเซลเซียสต่อนาที โครงสร้างผลึกและเฟสของ NBBSCT เซรามิกหลังจากเผาผนึกแล้วพบว่าทุกปริมาณการเจือพบโครงสร้างผลึกรูปแบบคิวบิกของเพอรอฟสไกต์และไม่พบเฟสทุติยภูมิ ขนาดเกรนเฉลี่ยลดลงเมื่อปริมาณการเจือแมงกานีสสูงขึ้น โดยขนาดเกรนเฉลี่ยอยู่ในช่วง 8.07 ถึง 11.08 ไมโครเมตร ความหนาแน่นเฉลี่ยเท่ากับ 5.13 กรัมต่อลูกบาศก์เซนติเมตร เมื่อวิเคราะห์สมบัติทางไฟฟ้าพบว่าเซรามิก NBBSCT ที่ไม่ได้เจือแมงกานีสแสดงพฤติกรรมเป็นแบบรีแลกเซอร์เฟอโรอิเล็กทริก แต่เมื่อเจือแมงกานีสพบการสูญเสียพฤติกรรมแบบรีแลกเซอร์เฟอโรอิเล็กทริก อีกทั้งเมื่อปริมาณการเจือแมงกานีสสูงขึ้นค่าการสูญเสียไดอิเล็กทริกมีค่าสูงเพิ่มขึ้นตาม ประสิทธิภาพของการกักเก็บพลังงานของเซรามิก NBBSCT มีประสิทธิภาพลดลงเมื่อเพิ่มปริมาณการเจือแมงกานีสสูงมากขึ้น การศึกษาสมบัติแม่เหล็กพบว่าการเจือแมงกานีสเข้าไปในโครงสร้างทำให้เซรามิกแสดงพฤติกรรมแม่เหล็กแบบพาราแมกเนติก และเมื่อเพิ่มปริมาณการเจือแมงกานีสที่สูงมากขึ้นส่งผลให้ค่าแม่เหล็กอิ่มตัวมีค่าสูงเพิ่มขึ้นตาม

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Developing Mesoporous Silica Nanoparticle-Based Stimuli-Responsive Nanocarriers For Delivery Of Small Molecule Therapeutics Against Colon Cancer Cells, Nisitha Lakmal Wellala Wijewantha Jan 2023

Developing Mesoporous Silica Nanoparticle-Based Stimuli-Responsive Nanocarriers For Delivery Of Small Molecule Therapeutics Against Colon Cancer Cells, Nisitha Lakmal Wellala Wijewantha

Dissertations and Theses

This dissertation delves into the innovative application of mesoporous silica nanoparticles (MSNs) for targeted drug delivery in colorectal cancer (CRC), one of the most prevalent and deadly forms of cancer worldwide. The initial focus of the research is on developing enzyme-responsive MSNs loaded with veratridine (VTD), an alkaloid derived from natural sources that demonstrates potent anticancer activity. The nanoparticles have been engineered to deliver VTD selectively to CRC cells, releasing the payload upon being exposed to specific enzymes primarily secreted by these cells. This strategy has dual advantages of amplifying the anticancer effects while minimizing potential side effects on healthy …

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Silver Doped Nanoceria (Agcnp) Integrated Silk Scaffold For Chronic Wound Healing, Architha K. Venkatesan Jan 2023

Silver Doped Nanoceria (Agcnp) Integrated Silk Scaffold For Chronic Wound Healing, Architha K. Venkatesan

Honors Undergraduate Theses

Chronic wound healing can be seriously impeded by the formation of biofilms, infections, peri-wound edema, hematoma, osteomyelitis, and the formation of reactive oxidative species (ROS). We hypothesize that a scaffold created from Silver-Doped Nanoceria (AgCNP) embedding silk can be beneficial to aid the wound healing process, inhibit inflammation and prevent microorganisms from forming a biofilm over the wound. Current wound healing methods such as intradermal injections are not advantageous to use since they can cause unwanted responses elsewhere in the body other than the wound site. Silk, however, has a positive impact on the wound healing effect and can be …

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