Engineering Commons^™

Designing Framework For The Computer Aided Design Of Silicon Carbide Jfet Circuits In Bleo Environments, Venkata Vinay Naidugari

Electronic Theses and Dissertations

Abstract: circuit design and testing are two essential processes to synthesis of an efficient and reliable circuit. Real-time testing of a circuit through circuit fabrication and development is an expensive and a risky procedure whereas testing the circuit by modelling and simulating is more efficient and inexpensive. Silicon-based semiconductors are the basic components of any modern day electronic devices, and their usage has dominated the marketplace. But these conventional cmos devices cannot exist in an environment consisting of harsh radiation, high temperature and many other environmental conditions, such as venus or mars. However, 6h-sic jfets, which are basic logic gate …

Phase Stability In Cobalt-Based L12 Quaternary Intermetallics From Density Functional Theory, William Earwood

Electronic Theses and Dissertations

The effects of higher order alloying additions (Mo, Ti, Ta, Hf, Fe, V) on the phase stability of L12 (γ’) intermetallics have been studied via first-principles. A 32 atom special-quasi-random structure was used to mimic the experimentally observed solid solution sublattice. Density of states distributions were generated in order to directly observe the impact of alloying additions on the position of the pseudogap and number of states at the Fermi level. Charge density differences across the supercell were visualized to analyze changes in bonding behavior. The results indicate that substitutions of Ti, Ta, and Hf in place of the central …

Extreme Weather Disaster Resilient Port And Waterway Infrastructure For Sustainable Global Supply Chain, Quang Van Nguyen

Electronic Theses and Dissertations

Global supply chain is largely dependent on seaports and marine terminals. Ports serve international cargo traffic for imports and exports. About 90% of the world’s goods are transported by sea and over 70% as containerized cargo ships. Coastal hurricanes/cyclones and rainfall flood disasters cause major disruptions for sea shipping traffic, disruptions of port infrastructure, and adverse impacts on coastal communities each year. Additionally, these weather related disasters threaten millions of people, damage infrastructure, and cost billions of dollars in global supply chain disruptions. Sustainable global supply chains, port infrastructure, and coastal community impact by these extreme weather disasters are the …

Geospatial Assessment Of Port Infrastructure And Computational Modeling Of Coastal Disasters, William Tucker Stafford

Electronic Theses and Dissertations

The research began with a review of recent natural disasters in the U.S. that shothere was an average of 121 federally declared disasters per year. Ports are critical to every country because they allow for the transport of commodities through that country and even internationally. If a natural disaster were to strike a port that was not properly prepared, the port would not only suffer, but the commodities that transported through there would be affected as well. The major motivation for this thesis was to address the risk of coastal disasters posed to people and critical infrastructure for port cities. …

Graphene Nano-Composites For Hypervelocity Impact Applications, Alharith Manasrah

Electronic Theses and Dissertations

The Low Earth Orbit (LEO) is a harsh environment cluttered with natural meteoroids and man-made debris, which can travel at velocities approaching 15 km/s. Most space activities within the LEO will encounter this environment. Thus, the spacecraft and its hardware must be designed to survive debris impact. This research introduces new procedures to produce a nano-composite material with mortar-brick nano-structure inspired from nacre. Nacre-like composites were successfully manufactured, based on three host polymers, with a wide range of graphene concentrations. The manufactured exfoliated graphene nano-platelet, embedded in a host polymer, provided good potential for enhancement of the hypervelocity impact (HVI) …

Comparing The Depositional Environment Of The Upper Smackover Formation In Southwestern Clarke County, Mississippi And Brooklyn/ Little Cedar Creek Field, Alabama, Elsie Ekene Okoye

Electronic Theses and Dissertations

This research evaluated the depositional settings of the upper Smackover formation in southwestern Clarke County (scc), Mississippi and compared its facies to those of the Brooklyn and little cedar creek fields (bf/lcc) in Conecuh and Escambia Counties, Alabama. The Smackover formation has been a prolific oil producing formation in the Gulf of Mexico since its discovery in Union County, Arkansas in 1937. The discovery of the lcc in 1994 and the bf in 2007 has generated additional interest in the Smackover. The bf/ lcc occur near the updip limit of the upper Jurassic (Oxfordian) Smackover formation. These fields produce from …

Analyses Of Pultruded Polyester/ E-Glass Composites Subjected To Environmental Degradation, Cameron Bosley

Electronic Theses and Dissertations

This paper evaluates the response of experimental mold releases for a pultruded glass fiber reinforced polymer (gfrp). The initial assessment criteria include comparisons between pull forces and surface appearances for each mold release. Composites fabricated using experimental mold releases that exhibited acceptable properties for both were used for further mechanical characterization that included environmental aging for two different exposure lengths (500 hours and 1000 hours) in five different environments: UV, bleach, hydrochloric acid, distilled water at 125â°f, and room temperature salt water. Three-point flexural bending and short beam strength tests were undertaken to determine the effects these environments would have …

Mechanical And Computational Evaluation Of Cementitious Materials With Hollow Glass Microsphere Inclusions, Zachary J. Wallace

Electronic Theses and Dissertations

The effect of volumetric replacement of cementitious materials by an inert filler known as hollow glass microspheres on elastic properties is evaluated in this study through a combined computational and experimental approach. This approach considered the variation in properties of type I Portland cement for 0, 5, 10, and 15% volume fractions of two kind of glass microspheres; one was high density with high crushing strength, and the other with a relative lower density. Using a suite of software called Virtual Cement and Concrete Testing Laboratory (VCCTL), the microstructural details were determined for 80% degree of hydration of the cement …

A Regional Study Of Wilcox Reservoirs In The Deepwater Northern Gulf Of Mexico, Margaret Elizabeth Dice

Electronic Theses and Dissertations

The Deepwater Wilcox trend covers more than 34,000 mi2, extending from the northwestern block, Alaminos Canyon, to Keathley Canyon, and to the north-central block, Walker Ridge. The Wilcox trend is widely studied in the oil and gas industry as it has significant proven hydrocarbons, but has considerable economic challenges due to the reservoir characteristics. The purpose of this study is to provide a regional study of the Wilcox reservoir economics and quality. Great white field is the most successful Wilcox field located in the northwestern Gulf of Mexico and Jack and St. Malo are the most successful Wilcox fields located …

Maximizing Cache Value For Distributing Content Via Small Cells In 5g, Ibrahim Khalaf Freewan

Electronic Theses and Dissertations

The objective of this thesis is to develop an algorithm for distributing content at small cells in 5G, wherein small cells (SCs) are set up instead of macro cells to serve mobile users. Users may simultaneously access between one and some maximum number of SCs, the actual number of SCs being drawn from a distribution. The source library is located away from these sites, and it stores files as a collection of RaptorQ-encoded symbols. By using RaptorQ symbols a very large number of distinct encoding symbols can be generated and a collection of received encoded symbols slightly larger than the …

Biphasic Cellulose Acetate/Rtil Membranes And Functionalized Graphene Adsorbents For Natural Gas Processing: Experimental And Molecular Simulation Studies, Amir Khakpay

Electronic Theses and Dissertations

In this dissertation, gas separation using membranes is investigated for natural gas upgrading. The main objectives of this study are separation of high value hydrocarbons such as propane (c3h8) from natural gas and carbon dioxide (co2) separation from light gases such as nitrogen (n2) and methane (ch4). To achieve these goals, supported ionic liquid membranes (silms), biphasic membranes, and nanoporous graphene (npg) and graphene oxide (npgo) membranes are studied. Biphasic membranes are proposed to overcome silms issues for gas separation. The major issues with silms are low room temperature ionic liquid (rtil) content and instability at high cross-membrane pressure. For …

Geospatial Analysis Of The Global Supply Chain And Transportation Infrastructure Considering Extreme Weather, Climate, And Sustainable Energy Policies, Craig Freeman Davis

Electronic Theses and Dissertations

The basis of this research is an investigation into the demand, costs, and emissions of a container freight shipping route from South America to the Port of Charleston, South Carolina. Ports and shipping routes play the most crucial role in the global supply chain, allowing people to maintain their standard of living. Once ashore, the delivery routes to five major metropolitan market cities were optimized for the lowest shipping costs for road and freight rail. The costs of transportation are a major factor in the ultimate price of consumer goods and thus must be minimized in the transportation process. Increasing …

Dynamic Analysis For Characterization Of Novel Biomass Based Composities, Aarsh Jigish Shah

Electronic Theses and Dissertations

Resources from forests constitute a significant asset of Mississippi State. Forests cover around 19.7 million acres (65%) of the total land area of Mississippi. Total annual economic impact of Mississippi’s forest products is about $17 billion. Creation of high-value products will lead to a number of economic benefits to the region. This work focuses on the study of bio-composite. Bio-composite materials are a ‘Green’ alternative to conventional materials which are readily recyclable and biodegradable. Taylor made properties are achievable in bio-composites, this being one of the significant advantages. Producing biodegradable products has become a necessity due to petroleum-based products being …

Effect Of Vibration Of Unconsolidated Sand On The Performance Of Interferometric Vibration Sensors, Cody Berrey

Electronic Theses and Dissertations

Interferometric vibration sensors are widely used for ground vibration measurements where traditional contact sensors are not desired. Laser Doppler vibrometers (LDV) and digital speckle pattern interferometers are studied in this thesis. The working principle of laser Doppler vibrometry and digital shearography is described. The effect of vibration of the unconsolidated sand on the performance of both sensors is experimentally investigated.

The vibration of unconsolidated sand can cause an increase of noise in the laser Doppler vibrometer output and cause speckle decorrelation in digital speckle pattern interferometry (referred to as digital shearography). An experimental investigation of the effect of varying the …

Band Gap Engineering Of Titania Systems Purposed For Photocatalytic Activity, Cameron Robert Thurston

Electronic Theses and Dissertations

Ab initio computer aided design drastically increases candidate population for highly specified material discovery and selection. These simulations, carried out through a first-principles computational approach, accurately extrapolate material properties and behavior. Titanium dioxide (tio2) is one such material that stands to gain a great deal from the use of these simulations. In its anatase form, titania (tio2) has been found to exhibit a band gap nearing 3.2 ev. If titania is to become a viable alternative to other contemporary photoactive materials exhibiting band gaps better suited for the solar spectrum, then the band gap must be subsequently reduced. To lower …