Engineering Commons^™

The Oxidation And Decoration Chemistry Of Platinum And Palladium Nanoparticles On Carbon Supports, Ritubarna Banerjee

Theses and Dissertations

Ultrasmall platinum and palladium nanoparticles supported on carbon are used in a wide variety of industrial catalytic processes including hydrogenation-dehydrogenation reactions, isomerization of hydrocarbons, ammonia and formic acid decomposition, the oxidation of carbon monoxide, alcohols and ammonia, and fuel cells. This dissertation covers three aspects of the chemistry of these ultrasmall, carbon supported nanoparticles.

In the first vein of work, the oft-observed discrepancy in Pd nanoparticle size estimation between chemisorption and other methods such as STEM and XRD is explored. It is demonstrated that lower-than-expected chemisorption uptake can stem from not only residual chloride, but also from the decoration of …

Modeling Embankment Breach Due To Overtopping, Ali Asghari Tabrizi

Theses and Dissertations

Despite numerous embankment failures around the world, in-depth assessments as well as reliable, comprehensive sets of data of such failures are limited. Detailed understanding of the earthen embankment failure process and the dominant parameters affecting the failure are needed to predict and model the breach process precisely. Therefore, a series of laboratory experiments on embankment (i.e., dam and levee) overtopping as well as erodibility measurements using the Submerged Jet test are conducted. Also, to study the influence of different model parameters (e.g., turbulence model, bedload formula), one of the dam embankment experiments is simulated. The main goal of this research …

Two-Stage Psa System For Co2 Removal And Concentration During Closed-Loop Human Space Exploration Missions, Hanife Erden

Theses and Dissertations

A novel two-stage pressure swing adsorption (PSA) system has been developed to remove metabolic CO2 removal from the spacecraft cabin air of the International Space Station (ISS). This PSA system enriches and recovers the CO2 to make it suitable for use in a Sabatier reactor (CO2 reduction). This two-stage PSA process utilizes Stage 1 to concentrate metabolic CO2 from about 0.2667 vol% to about 40 to 60 vol% and Stage 2 to further enrich the CO2 product from Stage 1 up to > 97 vol% CO2, while recovering at least 95% of it, which corresponds to removing 4.0 kg/day of CO2. …

System Level Analysis And Design For Wireless Inter-Chip Interconnection Communication Systems By Applying Advanced Wireless Communication Technologies, Xin Zheng

Theses and Dissertations

As the dramatic development of high speed integrated circuits has progressed, the 60 GHz silicon technology has been introduced to enable much faster computer systems and their corresponding applications. However, when signals are propagating at 60 GHz or higher frequencies on a PCB (Printed Circuit Board), the crosstalk among signal buses and devices, trace losses, and introduced parasitic capacitance and inductance between high density traces, become significant and may be severe enough such that the inter-chip communications will not be able to meet computer system signal specifications. High speed circuit signal integrity researchers in both electronic industries and academia have …

Numerical Studies Of Arterial Tissue Failure, Xiaochang Leng

Theses and Dissertations

Arterial tissue failure leads to a number of potentially life-threatening clinical conditions, such as atherosclerotic plaque rupture and aortic dissection which develop unpredictably and rapidly in vivo. Thus, a full understanding of the two conditions will provide a solid basis for medical advances in the intervention and prevention of the occurrence of this life-threatening event. The present work aims to develop a cohesive zone model (CZM) approach for analysis and simulation of arterial tissue failure, such as plaque and fibrous cap delamination and tearing, and to validate simulation predictions with experimental results.

To characterize the hysteresis phenomenon of diseased aortic …

Nano Oil Additives And Their Effect On Uh-60 Auxiliary Power Unit Performance, James Patrick Folk

Theses and Dissertations

This study is designed to research the tribological properties of nano oils developed by NanoPro MT and to determine their effects on fuel consumption in an UH-60 Blackhawk Auxiliary Power Unit (APU). For this work, two different nano oils were tested and compared against the performance of conventional oil. The first nano oil mixture contains proprietary nanodiamond particles and the second nano oil contains a mix of zinc sulfide, boron nitride, and graphene particles. Aeroshell 560 was used as the conventional oil and was blended with the nano particles to create both nano oils. This oil meets the military specifications …

Studies Of Asphalt Roofing Sealant Failure For Shingle Systems Subjected To High Wind Conditions For Both Elastic And Viscoelastic Sealant Material Response, Artem Aleshin

Theses and Dissertations

It has been documented that the sealant between asphalt roof shingles may delaminate at significantly lower wind speeds than those for which they are rated, with major consequences on safety and repair costs. In perspective, developing more resilient material systems and devising more effective installation procedures are sensible strategies to mitigate this problem. A practical approach may also entail adding a second self-sealing strip. In the first portion of this thesis, the elastic structural response of an asphalt roof shingle-sealant system consisting of individual three-tab shingles, which are bonded to the underlying shingles with two sealant strips and are subjected …

Estimation Of Basic And Mission Benefit Of Condition-Based Maintenance Deployment In Hums Equipped Ah-64 Aircraft Using Nlp And Regression Analysis, Tanzina Zaman

Theses and Dissertations

Condition-based maintenance (CBM) is a maintenance practice that involves regular monitoring of the mechanical condition of components of interest, processing of information collected, and then decision-making to ensure both maximizing the time interval between repairs and minimizing the number of unscheduled failures. CBM also offers early detection of failure which can prevent major breakdowns and repairs. Vibration monitoring is one of the effective techniques for condition monitoring. Health and Usage Monitoring System (HUMS) is a powerful tool for aviation industry which monitors health status and trending data. Vibration Monitoring Unit (VMU) and Modernized Signal Processing Unit (MSPU) are two forms …

Investigation And Development Of Friction Stir Welding Process For Unreinforced Polyphenylene Sulfide And Reinforced Polyetheretherketone, Hossain Ahmed

Theses and Dissertations

The joining of thermoplastics through welding, a specific form of fusion bonding, offers numerous advantages over mechanical joining. It eliminates the use of costly fasteners and has only a limited effect on the strength of the parts being joined since it does not require the introduction of holes and loading pins, and it does not create significant stress concentrations. A specific form of welding, Friction Stir Welding, was investigated for the creation of butt joints of unreinforced polyphenylene sulfide (PPS) and short carbon fiber reinforced polyetheretherketone (PEEK) plates. Friction stir welding requires a rotating pin, a shoulder arrangement, relative movement …

Solving Atomic Structures Using Statistical Mechanical Searches On X-Ray Scattering Derived Potential Energy Surfaces, Christopher James Wright

Theses and Dissertations

Engineering the next generation of materials, especially nanomaterials, requires a detailed understanding of the material’s underlying atomic structure. These structures give us better insight into structure-property relationships, allowing for property driven material design on the atomic level. Even more importantly, understanding structures in-situ will translate stimuli and responses on the macroscopic scale to changes on the nanoscale. Despite the importance of precise atomic structures for materials design, solving atomic structures is difficult both experimentally and computationally. Atomic pair distribution functions (PDFs) provide information on atomic structure, but the difficulty of extracting the PDF from x-ray total scattering measurements limits their …

Uncertainty Quantification In Computational Catalysis, Eric Alan Walker

Theses and Dissertations

This dissertation augments the field of computational catalysis with uncertainty quantification. An efficient tool to describe the energetics and structure of atomistic systems is density functional theory (DFT). DFT may be used to understand how catalysts work although DFT is inexact in nature due to approximations necessary for computational tractability. These approximations in DFT cause uncertainty in microkinetic model results for catalytic systems. Therefore, reliable model results gained from DFT include a quantification of uncertainty. The case study to examine a systematic framework for uncertainty quantification is water-gas shift (WGS CO+H2O⇌CO2+H2) reaction by Pt/TiO2 catalyst.

Uncertainties are represented with probabilities …

Positive Feedforward Control Design For Stabilization Of A Single-Bus Dc Power Distribution System Using An Improved Impedance Identification Technique, Silvia Arrúa

Theses and Dissertations

Due to recent advances in power electronics technology, DC power distribution systems offer distinct advantages over traditional AC systems for many applications such as electric vehicles, more electric aircrafts and industrial applications. For example, for the All-Electric ship proposed by the U.S. Navy the preferred design option is the adoption of a Medium Voltage DC power distribution system, due to the high power level required on board and the highly dynamic nature of the electric loads.

These DC power distribution systems consist of generation units, energy storage systems and different loads connected to one or more DC busses through switching …

Life-Cycle Analysis Of A Cement Manufacturing Plant Co-Firing Hazardous Waste In The Usa, Stephen P. Holt

Theses and Dissertations

The purpose of this work was to determine the overall environmental impacts associated with the co-firing hazardous waste by burning in a cement kiln to replace the use of coal in the cement manufacturing process. This environmental assessment was conducted using LCA methodology. Understanding the environmental impacts associated with burning hazardous waste in a cement factory could help shape national environmental policy, regulations and the need for site specific human health risk assessments in the environmental regulatory permitting processes. Accordingly, the primary objective of this study was to evaluate the environmental impacts from the hazardous waste burning for energy recovery …

Methane Separation And Purification Via Pressure Swing Adsorption, Lutfi Erden

Theses and Dissertations

Investigations on alternative energy sources have gained increasing attention due to significant shortage in the fossil fuel reserves and increase on the usage of internal combustion engines. Natural gas which mainly consists of Methane has a significant role in short term solution of this issue. Although methane as a greenhouse gas is over 20 times more potent by weight than carbon dioxide, if released directly into the atmosphere, it is a valuable energy source. However, methane is not extracted % 100 pure from the source. Natural gas generally contains many other contaminants such as water, other hydrocarbons, Carbon dioxide, Nitrogen, …

Automated Tool Selection And Tool Path Planning For Free-Form Surfaces In 3-Axis Cnc Milling Using Highly Parallel Computing Architecture, Andrey Balabokhin

Theses and Dissertations

This research presents a methodology to automatically select cutters and generate tool paths for all stages in 3-axis CNC Milling of free-form surfaces. Tools are selected and tool paths are planned in order to minimize the total machining time. A generalized cutter geometry model is used to define available cutters and an arbitrary milling surface is initially defined by a triangular mesh.

The decisions made by process engineers in selecting cutting geometry and generating tool paths for milling dramatically influence the final result. Often, the resulting tool path is non-optimal, because the engineers cannot consider all the available information. However, …

Dosimetry, Activation, And Robotic Instrumentation Damage Modeling Of The Holtec Hi-Storm 100 Spent Nuclear Fuel System, C. Ryan Priest

Theses and Dissertations

The Holtec HI-STORM 100 spent fuel storage system is an intermediate storage mechanism for SNF assemblies. Long term licensing and storage requires consideration of material degradation of the stainless steel multi-purpose canister holding the spent fuel. This material degradation is predicted to take the form of environmentally assisted cracking on weld interfaces of the stainless steel cylinder. Several of these spent fuel storage arrays are located in coastal environments. These sites include both the Hope Creek and Diablo Canyon nuclear power stations. A multi-sensory robotic package is being designed for non-destructive assay of the cask annular environment. It will be …

Guided Wave Inspection Of Cracks In The Rivet Hole Of An Aerospace Lap Joint Using Analytical-Fem Approach, Md Yeasin Bhuiyan

Theses and Dissertations

Ultrasonic guided waves are very attractive for the inspection of large structures using nondestructive evaluation (NDE) and structural health monitoring (SHM) technique. Combined analytical and finite element analysis (CAFA) has been introduced for the detection of butterfly cracks in the rivet hole of the aerospace lap joint. Finite element analyses have been performed on the local damage area in spite of the whole large structure. Fundamental Lamb wave modes (S0 and A0) have been strike on the local damage from multiple directions to analyze the cracks of multiple-rivet-hole lap joint. The rivet hole cracks (damage) in the plate structure gives …

Physics Based Modeling Of Guided Waves For Detection And Characterization Of Structural Damage In Nde And Shm, Banibrata Poddar

Theses and Dissertations

Guided waves based damage detection techniques are popular for their ease of generation and detection along with their ability to travel long distances. Accurate and efficient modeling is a key for successful implementation of guided waves for NDE/SHM. However, efficient prediction of scattering from various damage is challenging due to the complex nature of these guided waves.

This dissertation presents as physics based efficient and accurate modeling techniques to predict ultrasonic wave propagation and their interaction with various damage. Detection and characterization of damage in structures can typically be divided into two categories, active and passive. This research is aimed …

Positioning Commuters And Shoppers Through Sensing And Correlation, Rufeng Meng

Theses and Dissertations

Positioning is a basic and important need in many scenarios of human daily activities. With position information, multifarious services could be vitalized to benefit all kinds of users, from individuals to organizations. Through positioning, people are able to obtain not only geo-location but also time related information. By aggregating position information from individuals, organizations could derive statistical knowledge about group behaviors, such as traffic, business, event, etc.

Although enormous effort has been invested in positioning related academic and industrial work, there are still many holes to be filled. This dissertation proposes solutions to address the need of positioning in people’s …

Investigation Of Wide Bandgap Semiconductor Devices For Radiation Detection Applications, Rahmi Orhon Pak

Theses and Dissertations

Radioactive materials, as they decay, generate different high-frequency electromagnetic radiation such as alpha particles, beta particles, x-rays, gamma-rays, and neutrons. Nuclear detectors could stop these high-energy ionizing radiations, collect and transport the charges generated to an external circuit, and produce an electrical signal which is amplified by readout electronics to measure the energy of nuclear interaction. Thus, nuclear detectors are important tools for accounting of radioactive materials and have widespread applications in nuclear power plants, nuclear waste management, in national security, in medical imaging such as x-ray mammography, digital chest radiography, CT scan, and in high energy astronomy for NASA …

Ndt And Shm Methods Of Damage Detection In Welded Structures, Saad Mohammed

Theses and Dissertations

There has been an increasing demand for Nondestructive Testing (NDT) and Structural Health Monitoring (SHM) techniques to continuously monitor during all processes of a structure to prevent catastrophic failure and reduce maintenance costs. NDT and SHM are inspection processes which form part of the quality assurance/quality control (QA/QC) scheme. Among NDT and SHM methods, ultrasonic and guided wave techniques are the most commonly and widely used in industry. Ultrasonic methods provide the advantage of accurately locating and dimensioning defects within structures. Most of these structures consist of welded joints because welding is an economical and efficient method for obtaining a …

Implementation Of Agile Project Management In The Classroom, Michael Jerrod Myers

Theses and Dissertations

The world of engineering and engineering practices is advancing rapidly. In response to this rapid change, engineering education practices have to advance to ensure students are properly trained for the workforce. The purpose of this report is to address and substantiate the hypothesis that if engineering instruction incorporated Agile project management methods, then students will be challenged by professors to accomplish course objectives with a systematic and timely approach that will improve assessment performance metrics and present the framework of how agile methods of project management can be integrated into the classroom. The agile methods incorporated will also encourage the …

Effects Of Process Variants On Metallurgical And Mechanical Properties In Friction Stir Welding Of Aluminum Alloys, Xiaomin Huang

Theses and Dissertations

Conventional shoulder friction stir welding (CSFSW) produces uneven heat input through welded material thickness: higher close to the top and lower close to the bottom. When CSFSW is applied on certain aluminum alloys, such as 7xxx and 2xxx series high strength aluminum alloys which contain low melting point intermetallic, overheating and local melting may happen close to weld crown. Stationary shoulder friction stir welding (SSFSW) may generate much more uniform heat input through plate thickness than CSFSW due to the non-rotating shoulder and rotating pin. Therefore, overheating and local melting are expected to be avoided in SSFSW. Furthermore, local properties …

Evaluation Of Concrete Degradation Using Acoustic Emission: Data Filtering And Damage Detection, Marwa A. Abdelrahman

Theses and Dissertations

The prevalence of aging and deteriorating infrastructure in the U.S. has raised concerns regarding its level of serviceability, reliability, and vulnerability to natural disasters. This issue has gained attention recently and efforts are being conducted to accelerate the delivery of enhanced nondestructive testing (NDT) and structural health monitoring (SHM) methods. Acoustic emission (AE) is a strong candidate for these applications due to its high sensitivity and potential for damage detection in different materials. However, several challenges associated with the technique hinder the development of automated, reliable, real-time SHM using AE.

This study aims to advance the use of AE for …

Interest Detection In Image, Video And Multiple Videos: Model And Applications, Yuewei Lin

Theses and Dissertations

Interest detection is detecting an object, event, or process that draws attention. In this dissertation, we focus on interest detection in images, video and multiple videos. Interest detection in an image or a video is closely related to visual attention. However, the interest detection in multiple videos needs to consider all the videos as a whole rather than considering the attention in each single video independently.

Visual attention is an important mechanism of human vision. The computational model of visual attention has recently attracted a lot of interest in the computer vision community mainly because it helps find the objects …

Development Of A Pressure Swing Adsorption (Psa) Cycle For Co2 Capture From Flue Gas Using A 4-Bed Psa Apparatus, Joshua White

Theses and Dissertations

Pressure swing adsorption is an effective way to capture CO2 from flue gases in energy plants. Pressure swing adsorption utilizes an adsorbent’s selectivity to a specific compound to remove it from a feed stream. Zeolite 13X was used for this research to obtain a high purity and recovery of CO2 at a higher feed flow than previous research. The first part of the work was to use in house FORTRAN based Dynamic Adsorption Process Simulator (DAPS) that uses the finite difference method and the time adaptive Differential- Algebraic Equation (DAE) solver called DASPK to narrow down appropriate experiment criteria for …

Rational Design And Synthesis Of Pt/Silica-Alumina Metal-Acid Bifunctional Catalysts, Jadid Ettaz Samad

Theses and Dissertations

In the domain of rational catalyst design and synthesis, Strong Electrostatic Adsorption (SEA) has been applied with tremendous potential and use. In this study, SEA method has been advanced to thick slurries as well as to mixed oxide systems with a view to synthesizing stable, active and selective catalysts fine-tuned for specific applications.

The main objective was to synthesize metal-acid bifunctional catalysts with controlled ratio and proximity between metal and acid sites in order to analyze their effects on a bifunctional reaction. At first, the difference in charging behavior of silica and alumina in solution was used to selectively deposit …

Techno Economical Analysis Of Solid Oxide Iron-Air Redox Battery For Power Generation And Energy Storage, Farzana Yasmeen

Theses and Dissertations

The largest source of greenhouse gas emissions in the United States is from burning fossil fuels for electricity, heat, and transportation. Due to increasing environmental constraints associated with greenhouse gas emissions and uncertainty in the supply of fossil fuels, power systems of the future will become more reliable on renewable power source. To overcome the intermittency issue of renewable power, a promising cost effective electricity-storage systems is vital. The U.S. Department of Energy (DOE) has established detailed cost targets for energy storage system. One of the targets is capital cost which should be under $150/kWh for new technology. Another target …

Rational Synthesis To Optimize Ruthenium-Based Biomass Conversion Catalysts, Shuo Cao

Theses and Dissertations

With worldwide petroleum resources dwindling and greenhouse gas emissions rising, it is urgent to find renewable replacements for petroleum-derived products. A biomass-derived chemical with high potential as a platform intermediate, γ-valerolactone (GVL) can be readily synthesized by hydrogenation of levulinic acid (LA), itself a common biomass intermediate, using supported Ru catalysts. Overall, vapor phase hydrogenation is more energy sensitive as the higher boiling point of LA (~245°C) and requires a high energy input, comparable to liquid phase hydrogenation, which is more economical. To date the literature on many novel biomass conversion processes such as the hydrogenation of LA to GVL …

Improved Assessment Of The Magnitude And Acceleration Of Prehistoric Earthquakes In The South Carolina Coastal Plain, Emad Gheibi

Theses and Dissertations

Seismically-induced soil liquefaction is one the most hazardous geotechnical phenomenon that can cause loss of life and devastating damage to infrastructure. Proper estimation of critical ground motion parameters (e.g. peak ground acceleration and earthquake magnitude) is vital for seismic design of new structures and retrofit of existing structures, especially in regions such as the South Carolina Coastal Plain (SCCP) where the frequency of re-occurrence of large earthquakes is low (studies of paleoliquefaction features have revealed seven, large, prehistoric earthquakes occurring within the last 6000 years) and the locations of potential sources are not exactly known. Moreover, due to mechanical and …