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Theses/Dissertations

2017

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Full-Text Articles in Other Engineering Science and Materials

Computational Studies Of Structure–Function Relationships Of Supported And Unsupported Metal Nanoclusters, Hongbo Shi Nov 2017

Computational Studies Of Structure–Function Relationships Of Supported And Unsupported Metal Nanoclusters, Hongbo Shi

Doctoral Dissertations

Fuel cells have been demonstrated to be promising power generation devices to address the current global energy and environmental challenges. One of the many barriers to commercialization is the cost of precious catalysts needed to achieve sufficient power output. Platinum-based materials play an important role as electrocatalysts in energy conversion technologies. In order to improve catalytic efficiency and facilitate rational design and development of new catalysts, structure–function relationships that underpin catalytic activity must be understood at a fundamental level. First, we present a systematic analysis of CO adsorption on Pt nanoclusters in the 0.2-1.5 nm size range with the aim …


Numerical Simulation Of Multi-Phase Core-Shell Molten Metal Drop Oscillations, Kaushal Sumaria Oct 2017

Numerical Simulation Of Multi-Phase Core-Shell Molten Metal Drop Oscillations, Kaushal Sumaria

Masters Theses

The surface tension of liquid metals is an important and scientifically interesting parameter which affects many metallurgical processes such as casting, welding and melt spinning. Conventional methods for measuring surface tension are difficult to use for molten metals above temperatures of 1000 K. Containerless methods are can be used to measure the surface tension of molten metals above 1000 K. Oscillating drop method is one such method where a levitated droplet is allowed to undergo damped oscillations. Using the Rayleigh’s theory for the oscillation of force-free inviscid spherical droplets, surface tension and viscosity of the sample can be calculated from …


3d Printing Of 316l Stainless Steel And Its Effect On Microstructure And Mechanical Properties, Rawn Penn Oct 2017

3d Printing Of 316l Stainless Steel And Its Effect On Microstructure And Mechanical Properties, Rawn Penn

Graduate Theses & Non-Theses

Laser powder bed fusion or 3D printing is a potential candidate for net shape forming and manufacturing complex shapes. Understanding of how various parameters affect build quality is necessary. Specimens were made from 316L stainless steel at 0°, 30°, 60°, and 90° angles measured from the build plate. Three tensile and four fatigue specimens at each angle were produced. Fracture morphology investigation was performed to determine the fracture mode of specimens at each build angle. Microstructural analysis was performed on one of each orientation. The average grain size of the samples was marginally influenced by the build angle orientation. Tensile …


Correlating Long-Term Lithium Ion Battery Performance With Solid Electrolyte Interphase (Sei) Layer Properties, Seong Jin An Aug 2017

Correlating Long-Term Lithium Ion Battery Performance With Solid Electrolyte Interphase (Sei) Layer Properties, Seong Jin An

Doctoral Dissertations

This study was conducted to understand effects of some of key factors (i.e., anode surface properties, formation cycling conditions, and electrolyte conditions) on solid electrolyte interphase (SEI) formation in lithium ion batteries (LIBs) and the battery cycle life. The SEI layer passivates electrode surfaces and prevents electron transfer and electrolyte diffusion through it while allowing lithium ion diffusion, which is essential for stable reversible capacities. It also influences initial capacity loss, self-discharge, cycle life, rate capability and safety. Thus, SEI layer formation and electrochemical stability are primary topics in LIB development. This research involves experiments and discussions on key factors …


Bear Minimum: Ultralight Composite Bear Canister, Rama B. Adajian, Adam C. Eisenbarth Jun 2017

Bear Minimum: Ultralight Composite Bear Canister, Rama B. Adajian, Adam C. Eisenbarth

Mechanical Engineering

The ultralight backpacking community needs a strong, easy to use, safe bear canister that is lighter than current market products for trekking in the backcountry. A full design of the lid for the bear canister is to be completed. This includes the locking mechanism to ensure it is bear proof, the interface between the lid and the canister, and the structure of the lid so it passes the strength and weight specifications. The lid, along with the already designed canister body, is to be manufactured with formal documentation. The lid will initially be tested separately and then with the canister …


The Development Of A Vacuum Forming System For Kydex® And Other Thermoplastic Sheet, Andrew G. Smith May 2017

The Development Of A Vacuum Forming System For Kydex® And Other Thermoplastic Sheet, Andrew G. Smith

Electronic Theses and Dissertations

Vacuum forming is a popular, cost effective method amongst large and small scale applications. The method is used to mold a material to the surface of a mold/pattern in order to create a negative copy for reproduction or an object in positive form. The prototype vacuum forming system developed and documented herein is of a membrane-seal type that consists of three (3) principle parts: radial platen, Hinged Frame and Platen Support Assembly, and a PVC surge tank. Each part is described in detail through design, manufacturing, and testing processes. The design supports functional versatility, small scale molding, and uses readily …


Data Driven Discovery Of Materials Properties., Fadoua Khmaissia May 2017

Data Driven Discovery Of Materials Properties., Fadoua Khmaissia

Electronic Theses and Dissertations

The high pace of nowadays industrial evolution is creating an urgent need to design new cost efficient materials that can satisfy both current and future demands. However, with the increase of structural and functional complexity of materials, the ability to rationally design new materials with a precise set of properties has become increasingly challenging. This basic observation has triggered the idea of applying machine learning techniques in the field, which was further encouraged by the launch of the Materials Genome Initiative (MGI) by the US government since 2011. In this work, we present a novel approach to apply machine learning …


Adsorption Of Salicylhydroxamic Acid On Selected Rare Earth Oxides And Carbonates, Greer Galt Apr 2017

Adsorption Of Salicylhydroxamic Acid On Selected Rare Earth Oxides And Carbonates, Greer Galt

Graduate Theses & Non-Theses

Adsorption behavior of the anionic collector salicylhydroxamic acid (SHA) on a selected group of rare earth oxides (REOs) and carbonates (RECs) was studied via experimental methods and modelling software. Synthetic oxide and carbonate powders of the rare earth elements cerium (Ce), praseodymium (Pr), europium (Eu), and terbium (Tb) were tested for this research. Studies were conducted at different pH levels to analyze the kinetics of collector adsorption onto the oxide and carbonate surfaces in attempts to optimize recovery parameters for commercial flotation processes using SHA. In addition, thermodynamic software StabCal was implemented to compare theoretical adsorption behavior of collectors SHA …


High Performance Silver Diffusive Memristors For Future Computing, Rivu Midya Mar 2017

High Performance Silver Diffusive Memristors For Future Computing, Rivu Midya

Masters Theses

Sneak path current is a significant remaining obstacle to the utilization of large crossbar arrays for non-volatile memories and other applications of memristors. A two-terminal selector device with an extremely large current-voltage nonlinearity and low leakage current could solve this problem. We present here a Ag/oxide-based threshold switching (TS) device with attractive features such as high current-voltage nonlinearity (~1010), steep turn-on slope (less than 1 mV/dec), low OFF-state leakage current (~10-14 A), fast turn ON/OFF speeds (<75/250 ns), and good endurance (>108 cycles). The feasibility of using this selector with a typical memristor has been demonstrated by physically integrating them …


Developing An Insider Threat Experimental Environment, Eric Ortiz Jan 2017

Developing An Insider Threat Experimental Environment, Eric Ortiz

Electronic Theses and Dissertations

Simulated, 3D gaming environments have been used for a wide-range of applications including training, entertainment, and experimentation in an assortment of domains for some time. This can be attributed to their unique ability to emulate multifaceted situations that may be difficult to control, while affording participants the opportunity to operate in a relatively safe environment. In cybersecurity research, investigation of insider threat behavior is an endeavor that has received little attention in terms of available environments and resources for experimental manipulation. This research effort aimed to close this gap. A simulated, 3D gaming environment and accompanying scenarios were developed for …


The Impact Of Active Aerodynamics On Motorcycles Using Computational Fluid Dynamics Simulations, Aditya Sripathi Jan 2017

The Impact Of Active Aerodynamics On Motorcycles Using Computational Fluid Dynamics Simulations, Aditya Sripathi

All Graduate Theses, Dissertations, and Other Capstone Projects

Motorcycles are mostly utilized by commuters whose requirements are cheap and affordable transportation from point A to point B. Motorcycles also provide means to tour various places and have a leisure time for the majority of motorcyclists. Unfortunately, with pros also come cons such as accidents which are disabling or life-taking. According to motorcycle crash statistics produced every year, the majority of motorcycle crashes are caused due to facing unexpected obstacles in the path causing collisions due to insufficient braking time. Thus, this thesis serves as a mean to overcome this issue and provide a technological solution to the world …