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Articles 5041 - 5070 of 16708

Full-Text Articles in Engineering

The Corrosion Of Stainless Steel Made By Additive Manufacturing: A Review, Gyeongbin Ko, Wooseok Kim, Kyungjung Kwon, Tae-Kyu Lee Mar 2021

The Corrosion Of Stainless Steel Made By Additive Manufacturing: A Review, Gyeongbin Ko, Wooseok Kim, Kyungjung Kwon, Tae-Kyu Lee

Mechanical and Materials Engineering Faculty Publications and Presentations

The advantages of additive manufacturing (AM) of metals over traditional manufacturing methods have triggered many relevant studies comparing the mechanical properties, corrosion behavior, and microstructure of metals produced by AM or traditional manufacturing methods. This review focuses exclusively on the corrosion property of AM-fabricated stainless steel by comprehensively analyzing the relevant literature. The principles of various AM processes, which have been adopted in the corrosion study of stainless steel, and the corrosion behaviors of stainless steel depending on the AM process, the stainless steel type, and the corrosion environment are summarized. In this comprehensive analysis of relevant literature, we extract …

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Static Fatigue Of Hi-Nicalon S Fiber Tows At 500°C In Air And In Silicic Acid-Saturated Steam, Richard J. Reinink Mar 2021

Static Fatigue Of Hi-Nicalon S Fiber Tows At 500°C In Air And In Silicic Acid-Saturated Steam, Richard J. Reinink

Theses and Dissertations

Recent developments in aerospace propulsion systems, along with emerging interest in hypersonic air vehicles has emphasized the need for materials which can withstand extreme service environments. The leading candidates for the structural components expected to operate in these environments are SiC-based ceramic matrix composites (CMCs). When a CMC component is subjected to thermomechanical loads in an aggressive environment during service, surface cracks form. As steam penetrates cracks in the SiC matrix, it becomes saturated with silicic acid, (SI(OH)4) and attacks the SiC fibers. The interaction between the Hi-Nicalon™ S SiC fibers and the (SI(OH)4)-saturated steam is …

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Comparing The Environmental Impacts Of Using Mass Timber And Structural Steel, Khang Hoang Nguyen, Steelee Knight Morgan Mar 2021

Comparing The Environmental Impacts Of Using Mass Timber And Structural Steel, Khang Hoang Nguyen, Steelee Knight Morgan

Construction Management

Although mass timber has seen a gradual rise in demand in the past, there has been a lack of extensive research on the environmental impacts of using mass timber as a primary structural framing material. This paper compares structural steel, and mass timber’s total embodied carbon emissions. Accurate estimates were made using plans and specs for different projects retrieved from semi-structured interviews. The estimates were input through the EC3 Calculator to provide extensive total carbon emissions measurements between each construction material. Using structural steel framing increased the project’s overall environmental impact by roughly 84% compared to using mass timber. The …

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Static Fatigue Of Hi-Nicalon™ S Ceramic Fiber Tows At 600°C In Air And Silicic Acid-Saturated Steam, Caleigh M. Nelson Mar 2021

Static Fatigue Of Hi-Nicalon™ S Ceramic Fiber Tows At 600°C In Air And Silicic Acid-Saturated Steam, Caleigh M. Nelson

Theses and Dissertations

Ceramic matrix composites (CMCs) have the potential to be utilized in applications such as hypersonic vehicles, aircraft leading edges, hot sections of engines, and rocket nozzles. Of particular interest are advanced SiC/SiC composites that can withstand the elevated temperatures and harsh oxidizing environments while maintaining their properties and structural integrity under an applied load. Steam, a major component of combustion environment, is one such aggressive oxidizing environment. As steam passes through the SiC/SiC composite, entering the composite interior through the cracks in the SiC matrix, it becomes saturated with silicic acid, Si(OH)4. Before incorporating SiC/SiC composites in the …

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Fatigue Of Two Oxide/Oxide Ceramic Matrix Composites At 1200°C In Air And In Steam. Effect Of Diamond Drilled Effusion Holes, Anthony R. Cabri Mar 2021

Fatigue Of Two Oxide/Oxide Ceramic Matrix Composites At 1200°C In Air And In Steam. Effect Of Diamond Drilled Effusion Holes, Anthony R. Cabri

Theses and Dissertations

The tension-tension fatigue behavior of two oxide-oxide ceramic matrix composites (CMCs) was investigated at 1200°C in laboratory air and steam. Both composites consist of a porous oxide matrix reinforced with laminated, woven mullite/alumina (NextelTM720) fibers. The first composite had an alumina matrix, while the second had an alumina-mullite matrix. First, we assessed the effects of incorporating mullite into the matrix material on fatigue performance by studying the tension-tension fatigue behavior of alumina-mullite matrix CMC. Second, we evaluated the effects of effusion holes on the alumina matrix CMC's fatigue performance. Specimens containing an array of 17 effusion holes of 0.5-mm diameter …

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On Road Coordinates For Autonomous Vehicle Guidance, Ricardo Jacome Mar 2021

On Road Coordinates For Autonomous Vehicle Guidance, Ricardo Jacome

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

A new roadmap framework is proposed to improve the guidance and trajectory prediction capabilities of connected and automated vehicles (CAVs). Independent of road shape determination through external sensors, the system serves as a backup for challenging conditions, such as low sensor visibility and adverse environmental effects (e.g., rain, fog, snow). Based on the fusion of vehicle dynamics principles, differential geometry, and road design standards, the roadmap framework provides a consolidated collection of critical reference points of roadway centerlines and information about the shape of the roadway in the vicinity of a vehicle, including curvature, optimal travel velocity, and road alignment …

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Fiber Optic Sensor Embedded Smart Helmet For Real-Time Impact Sensing And Analysis Through Machine Learning, Yiyang Zhuang, Qingbo Yang, Taihao Han, Ryan O'Malley, Aditya Kumar, Rex E. Gerald Ii, Jie Huang Mar 2021

Fiber Optic Sensor Embedded Smart Helmet For Real-Time Impact Sensing And Analysis Through Machine Learning, Yiyang Zhuang, Qingbo Yang, Taihao Han, Ryan O'Malley, Aditya Kumar, Rex E. Gerald Ii, Jie Huang

Electrical and Computer Engineering Faculty Research & Creative Works

Background: Mild traumatic brain injury (mTBI) strongly associates with chronic neurodegenerative impairments such as post-traumatic stress disorder (PTSD) and mild cognitive impairment. Early detection of concussive events would significantly enhance the understanding of head injuries and provide better guidance for urgent diagnoses and the best clinical practices for achieving full recovery. New method: A smart helmet was developed with a single embedded fiber Bragg grating (FBG) sensor for real-time sensing of blunt-force impact events to helmets. The transient signals provide both magnitude and directional information about the impact event, and the data can be used for training machine learning (ML) …

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Preparations And Electrocatalytic Ethanol Properties Of Palladium Intercalated Hydrotalcite, Shou-Xun Hu, Liang Li, Jun-Hao Yang, Liu-Qiang Li, Zhi-Hao Jin Feb 2021

Preparations And Electrocatalytic Ethanol Properties Of Palladium Intercalated Hydrotalcite, Shou-Xun Hu, Liang Li, Jun-Hao Yang, Liu-Qiang Li, Zhi-Hao Jin

Journal of Electrochemistry

High-performance electrocatalysts play a vital role in the commercial application of direct fuel cells. Current anode materials still have such problems as low activity, easy poisoning and high cost. In this study, a new type of nano- palladium (Pd) catalyst was prepared by dipping method using layered double hydroxides (LDHs) as the carrier. X-ray diffractometer, scanning electron microscope (SEM), inductively coupled plasma mass spectrometer (ICP-MS), energy spectrometer, transmission electron microscope (TEM), cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscope were used to analyze the structure and electrocatalytic performance of the catalyst. The results showed that the newly prepared Pd/Mg-Al-LDHs still maintained …

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Preparation Of Pdcoir Tetrahedron Nanocatalysts And Its Performance Toward Ethanol Oxidation Reaction, Zhi-Yuan Yu, Rui Huang, Jie Liu, Guang Li, Qian-Tong Song, Shi-Gang Sun Feb 2021

Preparation Of Pdcoir Tetrahedron Nanocatalysts And Its Performance Toward Ethanol Oxidation Reaction, Zhi-Yuan Yu, Rui Huang, Jie Liu, Guang Li, Qian-Tong Song, Shi-Gang Sun

Journal of Electrochemistry

As a new energy conversion device, direct ethanol fuel cells (DEFCs) are widely concerned because of their remarkable advantages such as high theoretical energy density and wide fuel sources. However, the rapid development of DEFCs has been severely impeded due to the sluggish kinetic process and toxic intermediates especially in their anodic reactions. Palladium (Pd)-based materials are considered to be excellent anode catalysts for DEFCs, especially under alkaline conditions. And further improving their performance is an important direction to promote the development of DEFCs. Surface structure and composition are the key factors affecting the performance of catalysts which can be …

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Preparation And Performance Investigation Of Li-Sgo Doped Semi-Ipns Porous Single Ion Conducting Polymer Electrolyte, Yun-Feng Zhang, Jia-Ming Dong, Chang Tan, Shi-Kang Huo, Jia-Ying Wang, Yang He, Ya-Ying Wang Feb 2021

Preparation And Performance Investigation Of Li-Sgo Doped Semi-Ipns Porous Single Ion Conducting Polymer Electrolyte, Yun-Feng Zhang, Jia-Ming Dong, Chang Tan, Shi-Kang Huo, Jia-Ying Wang, Yang He, Ya-Ying Wang

Journal of Electrochemistry

Herein, the lithiated sulfonated graphene oxide (Li-SGO) was successfully prepared via three steps by sulfonation of graphene oxide with 3-merraptnpropylt rimethnxysilane, oxidation of thiol into sulfonate with hydrogen peroxide and lithiation of sulfonate with aqueous lithium hydroxide. The as-prepared Li-SGO was then introduced into the semi-interpenetrating networks of single ion conducting polymer electrolyte (Li-SGO-FPAS) and poly vinylidenefluoride-hexafluoro propylene (PVDF-HFP) binder by in-situ polymerization to fabricate the porous single ion conducting polymer electrolyte membrane (Li-SGO-po-FPAS) generated from the poor compatibility between aromatic Li-SGO-FPAS and aliphatic PVDF-HFP binder. The key properties such as morphology, porosity, solvent uptake, mechanical …

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Influence Of Resveratrol On Performance Of Long-Term Storage’S Lithium-Ion Battery Electrolyte, Lei Zhang, Xu-Ping Zhang, Si-Wei Zhang, Quan-Chao Zhuang Feb 2021

Influence Of Resveratrol On Performance Of Long-Term Storage’S Lithium-Ion Battery Electrolyte, Lei Zhang, Xu-Ping Zhang, Si-Wei Zhang, Quan-Chao Zhuang

Journal of Electrochemistry

Electrolyte of lithium-ion battery usually goes through processes of filling, transportation and storage from the completion of manufacture to the use. Understanding the influence of long-term storage process on performance of lithium-ion battery electrolyte is of theoretical significance for production of lithium-ion battery. Scanning electron microscope (SEM) images showed that the solid electrolyte interface (SEI) film formed on the surface of the graphite electrode was thicker in the base electrolyte after 6 months of storage. The charge/discharge test results showed that the reversible cycle capacity and cycle stability (capacity retention rate) of graphite electrode decreased significantly after 6 months of …

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Research Progress In Electrodeposition Technology Of Titanium-Based Iridium Oxide Electrode, Dan-Dan Wu, Xu Wu Feb 2021

Research Progress In Electrodeposition Technology Of Titanium-Based Iridium Oxide Electrode, Dan-Dan Wu, Xu Wu

Journal of Electrochemistry

Titanium-based iridium oxide electrode has been widely used in various fields, such as electrocatalytic oxidation, biomedical applications, hydrometallurgical metal recovery, electro-osmotic dewatering, etc. At present, it is mainly prepared by traditional thermal decomposition method, however, which has high cost, cumbersome process, mainly relying on manual labor and cannot be mass-produced yet. It is, therefore, urgently necessary to explore new preparation technologies by focusing on electrodeposition technology, with technological characteristics such as eco-friendly and sustainable development. This article systematically discusses the research progress in iridium oxide electrodeposition preparation technology from the aspects of deposition solution formulation, base material selection and treatment, …

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Preparations And Electrochemical Properties Of Bc/Coni2S4@Ppy Flexible Composites For Supercapacitors, Si-Yuan Peng, Shi-Run Yang, Jing-Hong Zhou, Zhi-Jun Sui, Tao Zhang, Yi Shi, Xing-Gui Zhou Feb 2021

Preparations And Electrochemical Properties Of Bc/Coni2S4@Ppy Flexible Composites For Supercapacitors, Si-Yuan Peng, Shi-Run Yang, Jing-Hong Zhou, Zhi-Jun Sui, Tao Zhang, Yi Shi, Xing-Gui Zhou

Journal of Electrochemistry

Flexible supercapacitor is one of the most promising energy storage devices for portable and wearable electronic products due to its advantages of high power density, fast charging and long cycle life. Therefore, self-supporting flexible electrode materials with high performance have attained more and more attention both in academia and in industry recently. In this work, using bacterial cellulose (BC) as a flexible substrate, the bacterial cellulose/nickel-cobalt sulfide@polypyrrole (BC/CoNi2S4@PPy) flexible composites with three-dimensional porous network and good conductivity were prepared by a combined solvothermal-in-situ polymerization-vacuum filtration method. The samples were characterized by X-ray diffraction, …

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Syntheses Of Na3V2(Po4)2O2F As A Cathode For Sodium Ion Battery Application, Kai Wu Feb 2021

Syntheses Of Na3V2(Po4)2O2F As A Cathode For Sodium Ion Battery Application, Kai Wu

Journal of Electrochemistry

High-temperature solid-state method, hydro-thermal method and solvo-thermal method have been mainly employed to synthesize Na3V2(PO4)2O2F (NVPF) cathode materials. However, these methods are energy consuming and complicated, which is not applicable for a large scale industrial production. In this study, a rather low-temperature (70℃) co-precipitation strategy was proposed to synthesize NVPF cathode materials. The as-prepared NVPF cathode materials showed a spherical shape with a diameter of 400 ~ 500 nm, and exhibited a sodium storage of 105.6 mAh·g-1 and an efficiency of 90.06%. After a simple thermal process, the specific …

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Research Progress Of Sio2 Regrowth During Selective Etching Process In 3d Nand Manufacture Procedure, Zi-Han Zhou, Yun-Wen Wu, Ming Li, Su Wang Feb 2021

Research Progress Of Sio2 Regrowth During Selective Etching Process In 3d Nand Manufacture Procedure, Zi-Han Zhou, Yun-Wen Wu, Ming Li, Su Wang

Journal of Electrochemistry

As one of the most significant memory chips in semiconductor market, NAND has been developed from two-dimension (2D) to three-dimension (3D). Due to the three-dimensional memory structure of 3D NAND, the capacity density, read-write speed and reliability of memory chips have been greatly improved, as well as the reduction of power dissipation. It is by nitride-oxide selective etching process in the alternate stacked structure of 3D NAND that the inter-dielectric layers can be obtained. The more stack layers, the better performance of chips will be. Meanwhile, however, silicon dioxide (SiO2) would regrow on the corner of oxide layers, …

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Research Progress On Transition State Of Organic Electrode Materials, Xue-Qian Zhang, Zhou-Guang Lu, Wei-Wei Huang Feb 2021

Research Progress On Transition State Of Organic Electrode Materials, Xue-Qian Zhang, Zhou-Guang Lu, Wei-Wei Huang

Journal of Electrochemistry

With the increasing requirements for high energy density, long lifetime, high safety, environmentally friendly fabrication, and sustainable development of large energy storage devices, the society calls for new electrode materials in rechargeable batteries beyond traditional inorganic materials which are limited by specific capacity. Organic electrode materials have been widely used in rechargeable batteries due to their advantages of large theoretical capacity, designable structures and environmentally friendly fabrications. In this review, the radical intermediates of organic electrode materials produced in the charging-discharging process (redox reaction) and their types are systematically reviewed. The stability of radical intermediates controlled by changing the structure …

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Initial Assessment Of Liquefied Scrap Tire Concrete, Abdulkareem Kuaryouti, Christopher D. Eamon Feb 2021

Initial Assessment Of Liquefied Scrap Tire Concrete, Abdulkareem Kuaryouti, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

A new approach to incorporate scrap tire material into concrete was investigated, where two reclaimed waste tire components, carbon black and fuel oil, were used to replace a portion of water. The effect of “liquid tire” content to water ratios from 5-40% on an otherwise typical concrete mix were assessed, where compressive and flexural strength, flexural toughness, modulus of elasticity, and several fresh concrete properties were determined. Results were compared to typically expected results of traditional shredded tire mixes with equivalent tire content. It was found that the liquid tire mixes experienced significantly less losses of compressive strength and workability …

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Development Of Preparations Based On Local Components For Dust Suppression On Quarry Roads, Olikulov Fakhriyor, Mukhiddinov Bakhоdir, Vapoev Khusniddin, Zhurayev Shokhruh Feb 2021

Development Of Preparations Based On Local Components For Dust Suppression On Quarry Roads, Olikulov Fakhriyor, Mukhiddinov Bakhоdir, Vapoev Khusniddin, Zhurayev Shokhruh

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the work is to develop dust-collecting preparations based on local raw materials for the suppression of man-made dust formed on quarry paths. For this purpose, 4 types of the drug were created in the laboratory on the basis of domestic raw materials for dust suppression. The dependence of the viscosity and density of the created preparations on the concentration of components and temperature is studied. For the preparation of the solution of the created drug, a semi-industrial installation is created, which presents the general view and the process of preparing the solution. The spray of the prepared …

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Synthesis And Research Of Chelate Forming Sorbent Based On Carbamide, Formaldehyde, Ditizone, Chorieva Nigora, Ermuratova Nilufar, Turaev Khayit, Kasimov Sherzod Feb 2021

Synthesis And Research Of Chelate Forming Sorbent Based On Carbamide, Formaldehyde, Ditizone, Chorieva Nigora, Ermuratova Nilufar, Turaev Khayit, Kasimov Sherzod

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this study is the synthesis and study of a chelating sorbent for the extraction of ions of non-ferrous and noble metals. To achieve this goal, a sulfur-containing chelating sorbent based on carbamide, formaldehyde, and dithizone was synthesized and studied. The optimal conditions for the synthesis of the sorbent have been determined and studies have been carried out on the influence of the molar ratios of the starting materials on the composition, and physicochemical properties of the synthesized sorbent. The optimum temperature of polycondensation was taken as 90 °C, the reaction time is 2.5-3 hours, as a result, …

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Synthesis And Spectroscopic Study Of Complex Compounds Of Mn(Ii), Co(Ii), Ni(Ii), Cu(Ii) And Zn(Ii) Acetates With 2-Aminobenzimidazole, Gapurova Lobar, Kadirova Shakhnoza, Rakhmonоva Dilnoza, Olimova Manzura Feb 2021

Synthesis And Spectroscopic Study Of Complex Compounds Of Mn(Ii), Co(Ii), Ni(Ii), Cu(Ii) And Zn(Ii) Acetates With 2-Aminobenzimidazole, Gapurova Lobar, Kadirova Shakhnoza, Rakhmonоva Dilnoza, Olimova Manzura

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the work is to develop a synthesis procedure and obtain new complex compounds of transition metal acetates with 2-aminobenzimidazole (L), to study the composition and structure of the synthesized compounds by elemental, thermal, X-ray phase analysis and IR spectroscopy. A procedure for the synthesis of new complex compounds of Mn(II), Cо(II), Ni(II), Cu(II) and Zn acetates with 2-aminobenzimidazole was developed and the composition and structure of the synthesized complex compounds were studied using modern physicochemical methods. Coordination competing donor centers, electronic and geometric structures of the ligand molecule were studied on the basis of a quantum-chemical calculation …

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Effect Of Light On The Resistance Of Bi/Pb Superconductors Synthesized By Solar Energy, Gulamova Dilbara, Echonkulov Elyor, Jalilov Dilshod, Bobokulov Sirojiddin Feb 2021

Effect Of Light On The Resistance Of Bi/Pb Superconductors Synthesized By Solar Energy, Gulamova Dilbara, Echonkulov Elyor, Jalilov Dilshod, Bobokulov Sirojiddin

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the work is to expand the capabilities of solar technologies and areas of practical use of superconductors. The effect of white light on the interaction of superconducting ceramics with a magnet at room temperature was investigated. It has been established that the magnet is “ejected” by ceramic samples of nominal Bi1,7Pb0,3Sr2Ca(n-1)CunOy, (n = 5-20) under the influence of white light and there is no effect in the dark. The resistance of Bi/Pb superconducting ceramics is reduced by exposure to light compared to resistance in the dark. The resistance of ceramics containing higher superconducting higher superconducting phases Tc …

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Spectrophotometric Color Determination Of Ceramic Pigments For Construction Ceramics And Regional Innovation System, Kadyrova Dilorom, Mansurov Yulbarskhon, Abdusattarov Shakirjan Feb 2021

Spectrophotometric Color Determination Of Ceramic Pigments For Construction Ceramics And Regional Innovation System, Kadyrova Dilorom, Mansurov Yulbarskhon, Abdusattarov Shakirjan

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of this work is the spectrophotometric determination of the color of ceramic pigments for the development of technology for the production of high-quality ceramic paints of a wide color palette for decorating building ceramics, porcelain and faience products. In this regard, using the principles of heterovalent isomorphic substitution of atoms in crystals, the compositions of ceramic pigments were designed on the basis of the anorthite derivatives containing transition elements with the general formula Са1-хMexAl2+xSi2-xО8, where calcium and silicon ions were replaced by aluminum and transition element, Ме – Cо, Ni, Fe, Cr. The color characteristics were taken on …

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Characterization, Immobilization, And Polymer Related Applications Of Watermelon Seed Powder, A Practical Source Of Urease Enzyme, Anthony Quan Quoc Mai Feb 2021

Characterization, Immobilization, And Polymer Related Applications Of Watermelon Seed Powder, A Practical Source Of Urease Enzyme, Anthony Quan Quoc Mai

LSU Doctoral Dissertations

Urease enzyme was crystallized almost a century ago, and to this day its intrinsic stability is not ideal for everyday applications. This work introduces a new process by which a naturally encapsulated material, watermelon seed powder (WMSP), is characterized for its stability and activity. WMSP enzymatic activity has been measured for over a year at various storage conditions—exposed to ambient atmosphere for a year, WMSP retained above 90% activity. In aqueous conditions, the enzyme maintained above 60% activity after two months; with the addition of a preservative that number stays at about 90%. There is a pH shift of the …

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Fluid Separation And Network Deformation In Wetting Of Soft And Swollen Surfaces, Zhuoyun Cai, Artem Skabeev, Svetlana Morozova, Jonathan T. Pham Feb 2021

Fluid Separation And Network Deformation In Wetting Of Soft And Swollen Surfaces, Zhuoyun Cai, Artem Skabeev, Svetlana Morozova, Jonathan T. Pham

Chemical and Materials Engineering Faculty Publications

When a water drop is placed onto a soft polymer network, a wetting ridge develops at the drop periphery. The height of this wetting ridge is typically governed by the drop surface tension balanced by elastic restoring forces of the polymer network. However, the situation is more complex when the network is swollen with fluid, because the fluid may separate from the network at the contact line. Here we study the fluid separation and network deformation at the contact line of a soft polydimethylsiloxane (PDMS) network, swollen with silicone oil. By controlling both the degrees of crosslinking and swelling, we …

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Scale Model Test To Estimate Thermal Damage By Fire In Aircraft Cargo, Jian Gao, Tsuneyoshi Matsuoka, Yuji Nakamura Feb 2021

Scale Model Test To Estimate Thermal Damage By Fire In Aircraft Cargo, Jian Gao, Tsuneyoshi Matsuoka, Yuji Nakamura

Progress in Scale Modeling, an International Journal

The Federal Aviation Administration (FAA) requires fire detectors to alarm within one minute of the start of a fire in cargo compartments of airplanes. To determine whether such alarm timing works, investigations of the thermal damage to ceilings and other structures during the early stage of a fire were accomplished to demonstrate compliance with these FAA regulations. The objective was to test the feasibility of predicting convective heat transfer in early stage of a cargo compartment fire by conducting reduced scale (lab scale) experiments. First, the scaling laws was derived and validated. Then, full-scale and half-scale experiments were performed with …

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Under Pressure: Hydrogel Swelling In A Granular Medium, Jean François Louf, Nancy B. Lu, Margaret G. O'Connell, H. Jeremy Cho, Sujit S. Datta Feb 2021

Under Pressure: Hydrogel Swelling In A Granular Medium, Jean François Louf, Nancy B. Lu, Margaret G. O'Connell, H. Jeremy Cho, Sujit S. Datta

Mechanical Engineering Faculty Research

Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). Hydrogels hold promise in agriculture as reservoirs of water in dry soil, potentially alleviating the burden of irrigation. However, confinement in soil can markedly reduce the ability of hydrogels to absorb water and swell, limiting their widespread adoption. Unfortunately, the underlying reason remains unknown. By directly visualizing the swelling of hydrogels confined in three-dimensional granular media, we demonstrate that the extent of hydrogel swelling is …

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International Journal Of Electrical And Computer Engineering, Fred Lacy Feb 2021

International Journal Of Electrical And Computer Engineering, Fred Lacy

Faculty Publications

A superconductor has the ability to conduct electricity perfectly and exclude magnetic fields from its interior. In order to understand electromagnetic characteristics of superconductors, their material properties need to be examined. To facilitate this understanding, a theoretical model based on concepts of electromagnetics is presented to explain the electrical and magnetic properties of superconductors. The permittivity response is the key aspect of the model and it describes the electrical resistance response and why it vanishes at the material’s critical temperature. The model also explains the behavior of magnetic fields and why they cannot exist inside superconducting materials. The theoretical concepts …

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Discrete Element Modeling Of Hydrogel Extrusion, Rohit Boddu Feb 2021

Discrete Element Modeling Of Hydrogel Extrusion, Rohit Boddu

Theses and Dissertations

Hydrogels are widely used in extrusion bioprinting as bioinks. Understanding how the hydrogel microstructure affects the bioprinting process aids researchers in predicting the behavior of biological components. Current experimental tools are unable to measure internal forces and microstructure variations during the bioprinting process. In this work, discrete element modeling was used to study the internal interactions and the elastic deformation of the molecular chains within hydrogel networks during the extrusion process. Two-dimensional models of hydrogel extrusions were created in Particle Flow Code (PFC; Itasca Co., Minneapolis, MN). For our model's calibration, hydrogel compression testing was used in which a cluster …

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Photoinduced Trapping Of Charge At Sulfur Vacancies And Copper Ions In Photorefractive Sn2P2S6 Crystals, Timothy D. Gustafson, Eric M. Golden, Elizabeth M. Scherrer, Nancy C. Giles, A. A. Grabar, Sergey A. Basun, Jonathan E. Slagle [*], Larry E. Halliburton Feb 2021

Photoinduced Trapping Of Charge At Sulfur Vacancies And Copper Ions In Photorefractive Sn2P2S6 Crystals, Timothy D. Gustafson, Eric M. Golden, Elizabeth M. Scherrer, Nancy C. Giles, A. A. Grabar, Sergey A. Basun, Jonathan E. Slagle [*], Larry E. Halliburton

Faculty Publications

Electron paramagnetic resonance (EPR) is used to monitor photoinduced changes in the charge states of sulfur vacancies and Cu ions in tin hypothiodiphosphate. A Sn2P2S6 crystal containing Cu+ (3d10) ions at Sn2+ sites was grown by the chemical vapor transport method. Doubly ionized sulfur vacancies (V2+S) are also present in the as-grown crystal (where they serve as charge compensators for the Cu+ ions). For temperatures below 70 K, exposure to 532 or 633 nm laser light produces stable Cu2+ (3d9) ions, as electrons move from Cu+ ions to …

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Impact Of Grain Orientation And Phase On Volta Potential Differences In An Additively Manufactured Titanium Alloy, Jake T. Benzing, Olivia O. Maryon, Nik Hrabe, Paul H. Davis, Michael F. Hurley, Frank W. Delrio Feb 2021

Impact Of Grain Orientation And Phase On Volta Potential Differences In An Additively Manufactured Titanium Alloy, Jake T. Benzing, Olivia O. Maryon, Nik Hrabe, Paul H. Davis, Michael F. Hurley, Frank W. Delrio

Materials Science and Engineering Faculty Publications and Presentations

This work introduces a method for co-localized multi-modal imaging of sub-μm features in an additively manufactured (AM) titanium alloy. Ti-6Al-4V parts manufactured by electron beam melting powder bed fusion were subjected to hot isostatic pressing to seal internal porosity and machined to remove contour–hatch interfaces. Electron microscopy and atomic force microscopy-based techniques (electron backscatter diffraction and scanning Kelvin probe force microscopy) were used to measure and categorize the effects of crystallographic texture, misorientation, and phase content on the relative differences in the Volta potential of α-Ti and β-Ti phases. Given the tunability of additive manufacturing processes, …

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