Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Engineering Science and Materials

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 1681 - 1710 of 5708

Full-Text Articles in Engineering

Common Pool Resource Management: Assessing Water Resources Planning For Hydrologically Connected Surface And Groundwater Systems, Francisco Munoz-Arriola, Tarik Abdel-Monem, A. Amaranto Mar 2021

Common Pool Resource Management: Assessing Water Resources Planning For Hydrologically Connected Surface And Groundwater Systems, Francisco Munoz-Arriola, Tarik Abdel-Monem, A. Amaranto

Department of Mechanical and Materials Engineering: Faculty Publications

Common pool resource (CPR) management has the potential to overcome the collective action dilemma, defined as the tendency for individual users to exploit natural resources and contribute to a tragedy of the commons. Design principles associated with effective CPR management help to ensure that arrangements work to the mutual benefit of water users. This study contributes to current research on CPR management by examining the process of implementing integrated management planning through the lens of CPR design principles. Integrated management plans facilitate the management of a complex common pool resource, ground and surface water resources having a hydrological connection. Water …

Go to article

Part-Scale Thermal Simulation Of Laser Powder Bed Fusion Using Graph Theory: Effect Of Thermal History On Porosity, Microstructure Evolution, And Recoater Crash, Reza Yavari, Ziyad Smoqi, Alex Riensche, Ben Bevans, Humaun Kobir, Heimdall Mendoza, Hyeyun Song, Kevin Cole, Prahalada Rao Mar 2021

Part-Scale Thermal Simulation Of Laser Powder Bed Fusion Using Graph Theory: Effect Of Thermal History On Porosity, Microstructure Evolution, And Recoater Crash, Reza Yavari, Ziyad Smoqi, Alex Riensche, Ben Bevans, Humaun Kobir, Heimdall Mendoza, Hyeyun Song, Kevin Cole, Prahalada Rao

Department of Mechanical and Materials Engineering: Faculty Publications

Flaw formation in laser powder bed fusion (LPBF) is influenced by the spatiotemporal temperature distribution – thermal history – of the part during the process. Therefore, to prevent flaw formation there is a need for fast and accurate models that can predict the thermal history as a function of the part shape and processing parameters. In previous work, a thermal modeling approach based on graph theory was used to predict the thermal history in LPBF parts in less-than 20% of the time required by finite element-based models with error within 10% of experimental measurements. The present work transitions toward the …

Go to article

Shock Migration On An Oscillating Straked Delta Wing Using An Unsteady Euler Solver, Alexander J. Brown Mar 2021

Shock Migration On An Oscillating Straked Delta Wing Using An Unsteady Euler Solver, Alexander J. Brown

Theses and Dissertations

This research contributes to the understanding of Shock Induced Trailing Edge Separation (SITES) as a driver of Limit Cycle Oscillation (LCO) by performing a computational investigation of nonlinear aerodynamic phenomena on a straked delta wing in transonic flow, oscillating in pitch. ZEUS, an Euler-based aeroelastic solver with a boundary layer coupling scheme meant to capture viscous flow effects within the boundary layer, was used to analyze aerodynamic flow around the wing for various mean incidence angles, oscillation amplitudes, and Mach numbers within the transonic region. The dynamic characteristics of the airflow around the wing were investigated in order to characterize …

Go to article

Me-Em Enewsbrief, March 2021, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University Mar 2021

Me-Em Enewsbrief, March 2021, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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 …

Go to article

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, …

Go to article

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, …

Go to article

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 …

Go to article

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, …

Go to article

Chilling And Heat Accumulation Of Fruit And Nut Trees And Flower Bud Vulnerability To Early Spring Low Temperatures In New Mexico: Meteorological Approach, Koffi Djaman, Komlan Koudahe, Murali Darapuneni, Suat Irkmak Feb 2021

Chilling And Heat Accumulation Of Fruit And Nut Trees And Flower Bud Vulnerability To Early Spring Low Temperatures In New Mexico: Meteorological Approach, Koffi Djaman, Komlan Koudahe, Murali Darapuneni, Suat Irkmak

Department of Mechanical and Materials Engineering: Faculty Publications

Fruit and nut trees production is an important activity across the southwest United States and this production is greatly impacted by the local climate. Temperature is the main environmental factor influencing the growth and the productivity of the fruit and nut trees as it affects the trees’ physiology and the vulnerability of flower bud, flowers, and young fruit and nut to the low temperatures or spring frost. The objective of the present study is to estimate the chilling and heat accumulation of fruit and nut trees across New Mexico. Three study sites as Fabian Garcia, Los Lunas, and Farmington were …

Go to article

Fingering Behavior Of Flame Spread Over Solid Combustibles, Tsuneyoshi Matsuoka, Kentaro Nakashima, Takuma Kajimoto, Akihiro Yoshimasa, Yuji Nakamura Feb 2021

Fingering Behavior Of Flame Spread Over Solid Combustibles, Tsuneyoshi Matsuoka, Kentaro Nakashima, Takuma Kajimoto, Akihiro Yoshimasa, Yuji Nakamura

Progress in Scale Modeling, an International Journal

In this study, the fingering pattern formation and the following flamelet spreading over three different kinds of thick combustibles, i.e., Poly methacrylate (PMMA), Poly ethylene (PE) and Poly carbonate (PC) were observed and the effective Lewis number correlation was validated. Experiments were performed with a narrow channel apparatus. In addition to the kinds of solid fuel materials, the channel height and the oxidizer velocity were varied as experimental parameters. An image analysis method was developed to quantify the number, diameter and spread rate of the flamelets. Replacing the fuel thickness into the thermal thickness, the effective Lewis number which is …

Go to article

Characterization Of The Strain-Rate–Dependent Mechanical Response Of Single Cell–Cell Junctions, Amir Monemian Esfahani, Jordan Rosenbohm, Bahareh Tajvidi Safa, Nickolay V. Lavrik, Grayson Minnick, Quan Zhou, Fang Kong, Xiaowei Jin, Eunju Kim, Ying Liu, Yongfeng Lu, Jung Yul Lim, James K. Wahl Iii, Ming Dao, Changjin Huang, Ruiguo Yang Feb 2021

Characterization Of The Strain-Rate–Dependent Mechanical Response Of Single Cell–Cell Junctions, Amir Monemian Esfahani, Jordan Rosenbohm, Bahareh Tajvidi Safa, Nickolay V. Lavrik, Grayson Minnick, Quan Zhou, Fang Kong, Xiaowei Jin, Eunju Kim, Ying Liu, Yongfeng Lu, Jung Yul Lim, James K. Wahl Iii, Ming Dao, Changjin Huang, Ruiguo Yang

Department of Mechanical and Materials Engineering: Faculty Publications

Cell–cell adhesions are often subjected to mechanical strains of different rates and magnitudes in normal tissue function. However, the rate-dependent mechanical behavior of individual cell– cell adhesions has not been fully characterized due to the lack of proper experimental techniques and therefore remains elusive. This is particularly true under large strain conditions, which may potentially lead to cell–cell adhesion dissociation and ultimately tissue fracture. In this study, we designed and fabricated a single-cell adhesion micro tensile tester (SCAμTT) using twophoton polymerization and performed displacement-controlled tensile tests of individual pairs of adherent epithelial cells with a mature cell–cell adhesion. Straining the …

Go to article

Irrigation Management In Potato (Solanum Tuberosum L.) Production: A Review, Koffi Djaman, Suat Irkmak, Komlan Koudahe, Samuel Allen Feb 2021

Irrigation Management In Potato (Solanum Tuberosum L.) Production: A Review, Koffi Djaman, Suat Irkmak, Komlan Koudahe, Samuel Allen

Department of Mechanical and Materials Engineering: Faculty Publications

Limited water resources coupled with the increase of the human population calls for more efficient use of water in irrigated agriculture. Potato (Solanum tuberosum L.) is one of the most widely grown crops worldwide and is very sensitive to water stress due to its shallow rooting system. With the dilemma of potato sensitivity to drought and limited available water resources restricting crop production, researchers and crop growers have been investigating different approaches for optimizing potato yield and improving crop water use efficiency under different irrigation methods. While potato response to water is affected by other management practices such as fertilizer …

Go to article

Ultrasonic Mapping Of Hybrid Additively Manufactured 420 Stainless Steel, Luz D. Sotelo, Haitham Hadidi, Cody S. Pratt, Michael P. Sealy, Joseph A. Turner Feb 2021

Ultrasonic Mapping Of Hybrid Additively Manufactured 420 Stainless Steel, Luz D. Sotelo, Haitham Hadidi, Cody S. Pratt, Michael P. Sealy, Joseph A. Turner

Department of Mechanical and Materials Engineering: Faculty Publications

Metal hybrid additive manufacturing (AM) processes are suitable to create complex structures that advance engineering performance. Hybrid AM can be used to create functionally graded materials for which the variation in microstructure and material properties across the domain is created through a synergized combination of fully coupled manufacturing processes and/or energy sources. This expansion in the engineering design and manufacturing spaces presents challenges for nondestructive evaluation, including the assessment of the sensitivity of nondestructive measurements to functional gradients. To address this problem, linear ultrasound measurements are used to interrogate 420 stainless steel coupons from three manufacturing methods: wrought, AM, and …

Go to article

Unveiling Precipitation Behavior In Mg-Y Based Alloys, Qingchun Zhu, Yangxin Li, Zhigang Ding, Jian Wang, Yuxuan Liu, Huan Zhang, Tian Xie, Mingxu Wang, Hong Zhu, Tao Ying, Wei Liu, Xiaoquin Zeng Feb 2021

Unveiling Precipitation Behavior In Mg-Y Based Alloys, Qingchun Zhu, Yangxin Li, Zhigang Ding, Jian Wang, Yuxuan Liu, Huan Zhang, Tian Xie, Mingxu Wang, Hong Zhu, Tao Ying, Wei Liu, Xiaoquin Zeng

Department of Mechanical and Materials Engineering: Faculty Publications

Mg-Y based alloys exhibit a promising combination of strength and deformability through tuning precipitation and solute strengthening mechanisms and tailoring the activity of non-basal dislocations. Understanding the precipitation sequence of Mg-Y based alloys and its dependence on Yttrium concentration in the matrix will provide a guideline for fine tuning structure, morphology and distribution of precipitates in Mg-Y based alloys. In this paper, we explore the precipitation behaviors of Mg-11Y (wt%) and Mg-11Y-1Al (wt%) alloys using aberration-corrected scanning transmission electron microscopy, and rationalize the experimental observations based on first-principles density functional theory calculations. The precipitation sequence during ageing at 225 °C …

Go to article

A Single-Stage Passive Vibration Isolation System For Scanning Tunneling Microscopy, Toan T. Le Feb 2021

A Single-Stage Passive Vibration Isolation System For Scanning Tunneling Microscopy, Toan T. Le

Master's Theses

Scanning Tunneling Microscopy (STM) uses quantum tunneling effect to study the surfaces of materials on an atomic scale. Since the probe of the microscope is on the order of nanometers away from the surface, the device is prone to noises due to vibrations from the surroundings. To minimize the random noises and floor vibrations, passive vibration isolation is a commonly used technique due to its low cost and simpler design compared to active vibration isolation, especially when the entire vibration isolation system (VIS) stays inside an Ultra High Vacuum (UHV) environment. This research aims to analyze and build a single-stage …

Go to article

A Computational Study Of Cocrfeniti High Entropy Alloys: Phase Diagrams, Thermodynamics, And Mechanical Properties From Calphad And First Principles, Geraldine Anis Jan 2021

A Computational Study Of Cocrfeniti High Entropy Alloys: Phase Diagrams, Thermodynamics, And Mechanical Properties From Calphad And First Principles, Geraldine Anis

Theses and Dissertations

High entropy alloys (HEAs) are multi-component alloys, which are often defined as those consisting of at least 5 principal elements with concentrations ranging between 5 and 35 atomic weight percent (at.%). Since their introduction by Yeh et al. and Cantor et al. in 2004, HEAs have been found to possess many important properties and have become prime candidates for several high-performance applications such as high-temperature and biomedical applications. Despite their multi-principal element nature, many HEAs favor the formation of solid solution phases as opposed to the intermetallic phases expected for such systems. This was originally only attributed to their high …

Go to article

The Role Of Microenvironmental Cues And Mechanical Loading Milieus In Breast Cancer Cell Progression And Metastasis, Brandon D. Riehl, Eunju Kim, Tasneem Bouzid, Jung Yul Lim Jan 2021

The Role Of Microenvironmental Cues And Mechanical Loading Milieus In Breast Cancer Cell Progression And Metastasis, Brandon D. Riehl, Eunju Kim, Tasneem Bouzid, Jung Yul Lim

Department of Mechanical and Materials Engineering: Faculty Publications

Cancer can disrupt the microenvironments and mechanical homeostatic actions in multiple scales from large tissue modification to altered cellular signaling pathway in mechanotransduction. In this review, we highlight recent progresses in breast cancer cell mechanobiology focusing on cell-microenvironment interaction and mechanical loading regulation of cells. First, the effects of microenvironmental cues on breast cancer cell progression and metastasis will be reviewed with respect to substrate stiffness, chemical/topographic substrate patterning, and 2D vs. 3D cultures. Then, the role of mechanical loading situations such as tensile stretch, compression, and flow-induced shear will be discussed in relation to breast cancer cell mechanobiology and …

Go to article

Quantification Of Nitric Oxide Concentration Using Single-Walled Carbon Nanotube Sensors, Jakob Meier, Joseph Stapleton, Eric M. Hofferber, Abigail Haworth, Stephen D. Kachman, Nicole M. Iverson Jan 2021

Quantification Of Nitric Oxide Concentration Using Single-Walled Carbon Nanotube Sensors, Jakob Meier, Joseph Stapleton, Eric M. Hofferber, Abigail Haworth, Stephen D. Kachman, Nicole M. Iverson

Department of Mechanical and Materials Engineering: Faculty Publications

Nitric oxide (NO), a free radical present in biological systems, can have many detrimental effects on the body, from inflammation to cancer. Due to NO’s short half-life, detection and quantification is difficult. The inability to quantify NO has hindered researchers’ understanding of its impact in healthy and diseased conditions. Single-walled carbon nanotubes (SWNTs), when wrapped in a specific single-stranded DNA chain, becomes selective to NO, creating a fluorescence sensor. Unfortunately, the correlation between NO concentration and the SWNT’s fluorescence intensity has been difficult to determine due to an inability to immobilize the sensor without altering its properties. Through the use …

Go to article

Optimal Nonlinear Pid Speed Control Based On Harmony Search For An Electric Vehicle, Mohamed Shamseldin, Mohamed Abdel Ghany, Yahia Hendawey Jan 2021

Optimal Nonlinear Pid Speed Control Based On Harmony Search For An Electric Vehicle, Mohamed Shamseldin, Mohamed Abdel Ghany, Yahia Hendawey

Future Engineering Journal

the paper presents an efficient scheme for a Nonlinear PID (NPID) controller to improve the dynamic response of the Electric Vehicle (EV). The objective of the proposed controller is to track accurately the reference speed selected by the driver of the EV. A MATLAB/Simulink model is established and validated for the considered EV to study the system performance. The proposed NPID controller has been investigated by comparing it with the traditional PID controller. The optimal parameters of Both the NPID and PID controllers were obtained using the Harmony Search (HS) optimization technique based on a cost function. The desired rise …

Go to article

Mechanical Behavior Of Al–Al2cu–Si And Al–Al2cu Eutectic Alloys, Qian Lei, Jian Wang, Amitava Mitra Jan 2021

Mechanical Behavior Of Al–Al2cu–Si And Al–Al2cu Eutectic Alloys, Qian Lei, Jian Wang, Amitava Mitra

Department of Mechanical and Materials Engineering: Faculty Publications

In this study, laser rapid solidification technique was used to refine the microstructure of ternary Al–Cu–Si and binary Al–Cu eutectic alloys to nanoscales. Micropillar compression testing was performed to measure the stress–strain response of the samples with characteristic microstructure in the melt pool regions. The laser-remelted Al–Al2Cu–Si ternary alloy was observed to reach the compressive strength of 1.59 GPa before failure at a strain of 28.5%, which is significantly better than the as-cast alloy with a maximum strength of 0.48 GPa at a failure strain of 4.8%. The laser-remelted Al–Cu binary alloy was observed to reach the compressive …

Go to article

Multifunctional Polydopamine Nanomaterials For Biomedical And Environmental Applications, Hamed Gholami Derami Jan 2021

Multifunctional Polydopamine Nanomaterials For Biomedical And Environmental Applications, Hamed Gholami Derami

McKelvey School of Engineering Graduate Student Theses & Dissertations

Polydopamine (PDA), a synthetic and organic material, has emerged as a promising materialplatform for various applications in energy, environmental, and biomedical fields. PDA, formed by self-polymerization of dopamine, is rich in catechol and amine groups, which facilitate covalent conjugation and/or other non-covalent interactions with organic and inorganic materials. It is highly biocompatible, biodegradable, has broadband light absorption spectrum and excellent light-to-heat conversion efficiency. Also, it is easy to synthesize and functionalize. The combination of excellent characteristics of polydopamine-based nanomaterials, make them a promising adsorbent agent for environmental wastewater treatment and photothermal agent for biomedical applications. In the first half of …

Go to article

Mechanical Strength Of Germanium Doped Low Oxygen Concentration Czochralski Silicon And The Effect Of Oxygen On Nitrogen Dissociation In Silicon, Junnan Wu Jan 2021

Mechanical Strength Of Germanium Doped Low Oxygen Concentration Czochralski Silicon And The Effect Of Oxygen On Nitrogen Dissociation In Silicon, Junnan Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

During the Czochralski growth of silicon, it is inevitable for oxygen to be incorporated into the silicon crystal from the quartz crucible. Interstitial oxygen improves the mechanical strength of silicon by pinning and locking dislocations, but also generates thermal donors during device processes, shifting the electrical resistivity. For silicon wafers used in radio frequency (RF) applications, it is important to ensure the high resistivity of the substrates for good RF characteristics. Therefore, the oxygen level in these high resistivity silicon wafers is kept very low (< 2.5 × 1017 atoms/cm3) by carefully controlling the Czochralski growth conditions, in order to reduce the thermal donor concentration to an acceptable level. Silicon on insulator (SOI) substrates made from high resistivity wafers have been widely used for RF applications. SOI manufacturing includes multiple high temperature thermal cycles (1000 – 1100 °C), during which the high resistivity wafers are prone to slip and warpage. Therefore, it is technologically important to recover some of the lost mechanical strength due to the lack of oxygen by introducing electrically inactive impurities to suppress the dislocation generation and mobility in silicon. Germanium (Ge) as an isovalent impurity is 4% larger in size and forms a solid solution with silicon in the entire concentration range. Previous works have shown Ge doping at high concentrations above 6 × 1019 atoms/cm3 increased mechanical strength of silicon with high oxygen concentration (~ 1 × 1018 atoms/cm3). In this work, we explore the effect of Ge doping (7 - 9 × 1019 atoms/cm3) on the mechanical strength of low oxygen concentration (< 2 × 1017 atoms/cm3) silicon, where the oxygen associated dislocation locking and pinning are very low. A mechanical bending test was used to study the average dislocation migration velocity and the critical shear stress of dislocations motion at 600 – 750 °C for Ge doped, nitrogen doped, and undoped low oxygen samples, as well as nitrogen doped float-zone and un-doped high oxygen concentration samples. Next, we fabricated SOI substrates using these high resistivity wafers and compared their slip generation rates and the slip-free epitaxial grow temperature windows after the high temperature thermal cycles (> 1000 °C). Our results indicate at lower temperature Ge doesn’t affect the dislocation mobility …

Go to article

Nanoscale Enhancement Of Photosensitized Radionuclide Stimulated Therapy, Daniel Douglas Lane Jan 2021

Nanoscale Enhancement Of Photosensitized Radionuclide Stimulated Therapy, Daniel Douglas Lane

McKelvey School of Engineering Graduate Student Theses & Dissertations

Photodynamic therapy (PDT) provides efficient tumor killing through the generation of reactive oxygen species (ROS) from the optical excitation of a photosensitizer (PS). Furthermore, this mechanism is highly immune stimulating, providing systemic tumor immunity with a reduction in metastasis. However, these materials had previously been limited by their dependence upon external light sources, allowing treatment of only laser-accessible malignancy. With the recent development of photosensitized radiation stimulated therapy (PRaST) this depth dependence is broken through co-localization of radionuclides and semiconducting photosensitizers. This dissertation focuses on the enhancement of titanium dioxide (TiO2) based PRaST agents through understanding of TiO2 material parameters …

Go to article

Research Trend Of Metal Matrix Composites Reinforced With Silica Extracted By Green Route: A Bibliometric Analysis, Rinku Datkhile, Meena Laad, Babaji Ghule Jan 2021

Research Trend Of Metal Matrix Composites Reinforced With Silica Extracted By Green Route: A Bibliometric Analysis, Rinku Datkhile, Meena Laad, Babaji Ghule

Library Philosophy and Practice (e-journal)

Metal Matrix Composites have acquired an important place in the engineering applications due to their distinctive characteristics such as high specific strength, lower specific gravity, improved material stiffness, better durability, enhanced creep and fatigue strength etc. Worldwide scientists are working on the improvement of mechanical properties of composite materials. The present work attempts to summarise all the research carried out on metal matrix composites reinforced with silica extracted by green route and provides up-to-date research material for researchers who are interested in the field of composites with metal matrices. Scopus databases and software such as Gephi Vos Viewer and Table2Net …

Go to article

Sensitive X-Ray And Gamma-Ray Detectors Including Perovskite Single Crystals, Jinsong Huang, Haotong Wei Jan 2021

Sensitive X-Ray And Gamma-Ray Detectors Including Perovskite Single Crystals, Jinsong Huang, Haotong Wei

Department of Mechanical and Materials Engineering: Faculty Publications

Perovskite single crystal X-ray and gamma-ray radiation detector devices include an X-ray and gamma-ray wavelength responsive active layer including a perovskite single crystal. The perovskite single crystal is a perovskite single crystal having a structure of ABX3 , wherein A is methyl ammonium ( CH2NH2+), CS+, formamidinum ( H2NCHNH2+) , or Rb+ or a mixture thereof, B is Pb2+ which can be partially or completely replaced by other ions including Bi3+, Sb3+, Sn2+ or a mixture thereof, and X is a halide …

Go to article

Mini Rc Baja Car, Jason Schindler Jan 2021

Mini Rc Baja Car, Jason Schindler

All Undergraduate Projects

Incorporating each aspect of engineering incorporated into a senior project is difficult. That is why an RC Baja car is a great senior project for Mechanical Engineering students. The approach that students must take to design, construct, and test the car is to set parameters, and to make overall goals that can be easily measured. These goals include, but not limited to things like a $700 budget and the ability to withstand a 1-foot drop to a flat surface on all four wheels simultaneously. First, the design must meet the specifications and rules that are set previously. This ensures that …

Go to article

First Prev Next Last