Engineering Commons^™

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 …

Electrochemical Reduction Of Carbon Dioxide On Carbon Nanostructures: Defect Structures & Electrocatalytic Activity, Pranav Parag Sharma

Theses and Dissertations

The advantages of the electrochemical conversion of carbon dioxide to fuels using renewable energy sources are two-fold: (1) it has the potential to accomplish a carbon-neutral energy cycle and (2) it can provide an approach to tackle the environmental challenges caused by anthropogenic carbon dioxide emissions. Although thermodynamically possible, the kinetics of carbon dioxide reduction to fuels remains challenging and therefore, an efficient and robust electrocatalyst is needed to promote the reaction. The ideal catalyst for the electrochemical CO2 reduction must be capable of mediating multiple proton-coupled electron transfer reactions at low overpotentials, suppressing the concurrent hydrogen evolution reaction, converting …

Deposits Emplaced In Upper Regime, Ricardo Rafael Hernández Moreira

Theses and Dissertations

Relatively common to the submarine setting are depositional sequences that begin with a lower erosional boundary, followed in ascending order by a either a graded or an inherently massive basal unit, a relatively coarse parallel laminated unit, a cross laminated unit, a relatively fine parallel laminated unit, and a capping layer of massive mud. These sequences are present in turbidity current, coastal storm and tsunami deposits, and their study is the key to understanding the physical processes governing sediment transport, erosion and deposition in submarine settings, to the reconstruction of global paleoclimate and paleoflow, to the exploration of hydrocarbon reservoirs …

Hydro-Geological Flow Analysis Using Hidden Markov Models, Chandrahas Raj Venkat Gurram

Theses and Dissertations

Hidden Markov Models a class of statistical models used in various disciplines for understanding speech, finding different types of genes responsible for cancer and much more. In this thesis, Hidden Markov Models are used to obtain hidden states that can correlate the flow changes in the Wakulla Spring Cave. Sensors installed in the tunnels of Wakulla Spring Cave have recorded huge correlated changes in the water flows at numerous tunnels. Assuming the correlated flow changes are a consequence of system being in a set of discrete states, a Hidden Markov Model is calculated. This model comprising all the sensors installed …

Biodegradable Hybrid Tissue Engineering Scaffolds For Reconstruction Of Large Bone Defects, Danial Barati

Theses and Dissertations

Complex skeletal injuries and large bone fractures are still a significant clinical problem in US. Approximately 1.5 million Americans (veterans, their families, and civilians) every year suffer from bone loss due to traumatic skeletal injuries, infection, and resection of primary tumors that require extensive grafting to bridge the gap. The US bone graft market is over $2.2 billion a year. Due to insufficient mechanical stability, lack of vascularity, and inadequate resorption of the graft, patients with traumatic large skeletal injuries undergo multiple costly operations followed by extensive recovery steps to maintain proper bone alignment and length. Current strategies for repairing …

Regular Expression Synthesis For Blast Two-Hit Filtering, Jordan Bradshaw

Theses and Dissertations

Genomic databases are exhibiting a growth rate that is outpacing Moore's Law, which has made database search algorithms a popular application for use on emerging processor technologies. NCBI BLAST is the standard tool for performing searches against these databases, which operates by transforming each database query into a filter that is subsequently applied to the database. This requires a database scan for every query, fundamentally limiting its performance by I/O bandwidth. In this dissertation we present a functionally-equivalent variation on the NCBI BLAST algorithm that maps more suitably to an FPGA implementation. This variation of the algorithm attempts to reduce …

Efficient Partitioning And Allocation Of Data For Workflow Compositions, Annamaria Victoria Kish

Theses and Dissertations

Our aim is to provide efficient partitioning and allocation of data for web service compositions. Web service compositions are represented as partial order database transactions. We accommodate a variety of transaction types, such as read-only and write-oriented transactions, to support workloads in cloud environments. We introduce an approach that partitions and allocates small units of data, called micropartitions, to multiple database nodes. Each database node stores only the data needed to support a specific workload. Transactions are routed directly to the appropriate data nodes. Our approach guarantees serializability and efficient execution.

In Phase 1, we cluster transactions based on data …

Assessment, Prevention And Remediation Of Corrosion In Weathering Steel Transmission Line Poles, Matthew Bruce Barragan

Theses and Dissertations

Electric utilities routinely use weathering steel (WS) in transmission line structures, capitalizing on corrosion resistance and associated cost savings. The formation of a protective iron-oxide patina on uncoated above-ground WS surfaces depends on the operating environment and exposure conditions. In fact, exposure to common aggressive environments, such as those found in sulfate-contaminated industrial areas and chloride-laden coastal areas, may dramatically hinder the corrosion resistance of WS transmission line structures.

To assess the corrosion behavior of WS transmission line poles, field inspections were conducted at five test sites comprising diverse operating environments and pole designs. These sites included three locations in …

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 …

Applications Of Impedance Identification To Electric Ship System Control And Power Hardware-In-The-Loop Simulation, Jonathan Siegers

Theses and Dissertations

Recent advances in semiconductor technology, controls, and switching converter topologies have resulted in the increasing application of power electronics in power distribution systems. Power electronic enabled distribution systems have inspired a renewed interest in DC distribution architectures as an appealing alternative to traditional AC methods due to the significant performance and efficiency gains they offer. However, the notional power electronic based DC distribution system is a complex and extensively interconnected system consisting of multiple power converters. As a result, a number of system-level challenges related to stability arise due to interaction among multiple power converters. In addition, the power distribution …

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, …

Miniaturized Rf Components With A Novel Tunable Engineered Substrate For Wireless Communication Systems, Yujia Peng

Theses and Dissertations

There is an increasing demand for reliable sensor system capable of remote sensing and measuring interesting data. Although large communication range can be achieved, active wireless communication systems are still suboptimal in longtime applications due to their harmful battery supply. Inductively coupled passive devices, with the advantages in safe long-term implanting, structural simplicity, small fabrication footprint and low-cost production, are preferred in chronic monitoring, but little work has been done to optimize the performance of these systems, especially under some design constraints.

The model and optimization of an inductively coupled wireless pressure sensor system is presented in this dissertation. With …

A Comparison Of Fpga Implementation Of Latency-Based Solvers For Power Electronic System Real-Time Simulation, Matthew Aaron Milton

Theses and Dissertations

In the design of power systems, real-time simulation is a powerful tool to evaluate and validate designs before dedicating resources to develop such systems. Through use of real-time simulation, one can study the behavior of a power system in interaction with real, physical elements, all while avoiding the cost and risk in constructing and testing such systems before a design is finalized. In recent decades, effort has been made in the industry and academia to apply real-time simulation to that of switching power converters through use of high-speed digital signal processors (DSPs) and field programmable gate array (FPGA) devices. With …

Mathematical Modeling Of Transport And Corrosion Phenomenon Inside High Temperature Molten Salt Systems, Bahareh Alsadat Tavakoli Mehrabadi

Theses and Dissertations

In today's world, alternative clean methods of energy are needed to meet growing energy demands. Concentrating solar thermal power, more commonly referred to as CSP, is unique among renewable energy generators because even though it is variable, like solar photovoltaic and wind, it can easily be coupled with thermal energy storage as well as conventional fuels, making it highly dispatchable. One challenge with concentrated solar power (CSP) systems is the potential corrosion of the alloys in the receivers and heat exchangers at high-temperature (700-1000 °C), which leads to a reduction of heat transfer efficiency and influences the systems durability. The …

Wireless Channel Modeling For Networks On Chips, William Rayess

Theses and Dissertations

The advent of integrated circuit (chip) multiprocessors (CMPs) combined with the continuous reduction in device physical size (technology scaling) to the sub-nanometer regime will result in an exponential increase in the number of processing cores that can be integrated within a single chip. Today’s CMPs already support tens to low hundreds of cores and both industry and academic roadmaps project that future chips will have thousands of cores. Therefore, while there are open questions on how to harness the computing power offered by CMPs, the design of power-efficient and compact on-chip interconnection networks that connects cores, caches and memory controllers …

Detection Of Periodic Error And Structure Change Using Wavelet Analysis, Chao Lu

Theses and Dissertations

Heterodyne displacement measuring interferometry provides important metrology for applications requiring high resolution and accuracy. Heterodyne Michelson interferometers use a two-frequency laser source and separate the two optical frequencies into one fixed length and one variable length path via polarization. Ideally these two beams are linearly polarized and orthogonal so that only one frequency is directed toward each path. An interference signal is obtained by recombining the light from the two paths; this results in a measurement signal at the heterodyne (split) frequency of the laser source. This measurement signal is compared to the optical reference signal. Motion in the measurement …

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 …

The Application Of Lean Six Sigma To Improve A Business Process: A Study Of The Order Processing Process At An Automobile Manufacturing Facility, Sherrian Francina Ellis

Theses and Dissertations

The objective of this study is to explore the application of Lean Six Sigma to determine root causes of process inefficiency and make recommendations for improving the order processing process at an automobile manufacturing facility. State of the art process quality improvement initiatives Lean, Six Sigma, and Lean Six Sigma are used to explore literature and provide a strong theoretical background for this study. Since the study utilizes both quantitative and qualitative data, the study’s methodological approach is classified as mixed methodology. The study is empirical in nature, and single case study is strategy chosen to complete the study. The …

Use Of Biochar-Ultrafiltration Membrane Processes For Removal Of Humic Acid, Vaibhavi Shankar

Theses and Dissertations

The performance of an ultrafiltration (UF)-biochar process was evaluated in comparison with a UF membrane process for the removal of humic acid (HA). Bench-scale UF experiments were conducted to study the rejection and flux trends under various hydrodynamic, pH, conductivity, and pressure conditions. The resistance-in-series model was used to evaluate the processes and it showed that unlike stirred conditions, where low fouling resistance was observed, comparable trends were obtained for UF-biochar and UF alone for unstirred conditions. Thus, the processes were further evaluated under unstirred conditions. Additionally, total fouling resistance was decreased in the presence of biochar, indicating that HA …

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 …

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 …

Synthesis Of Well Dispersed Supported Metal Catalysts By Strong Electrostatic Adsorption And Electroless Deposition, John Meynard Macasero Tengco

Theses and Dissertations

Enhancing the catalytic performance of heterogeneous catalysts can be done by increasing active site count as well as modification of the physico-chemical characteristics of the catalyst material. For supported metal nanoparticles this can be achieved by decreasing particle size, thus increasing dispersion or metal utilization on the surface of the particles, while modification of metal properties can be attained by addition of a secondary metal that has a strong interaction to the primary metal, beneficial for a given reaction. In addition, the accessibility of the metal surface is necessary for reliable performance of catalysts. For carbon supported catalysts, Temperature Programmed …

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 …

Computational Doping For Fuel Cell Material Design Based On Genetic Algorithms And Genetic Programming, Emrah Atilgan

Theses and Dissertations

Developing new materials have historically been time-consuming. Computational material discovery can search large design space to identify promising candidates for experimental verification. Recently, Density Functional Theory (DFT) based first principle calculation has been able to calculate many electrical and physical properties of materials, making them suitable for computational doping based material discovery. In material doping, given a base material, one can change its properties by substituting some elements with new ones or adding additional elements. In computational doping, we have a grid of atoms in a supercell, some of which can be substituted with dopant atoms. There are many possible …

Age-Related Liquefaction Resistance Of Pleistocene Coastal Plain Sands In South Carolina, Michael J. Hasek

Theses and Dissertations

Soils of Pleistocene age in the South Carolina Coastal Plain have experienced liquefaction due to historic and pre-historic earthquakes. Numerous field and laboratory studies have shown that aged soil deposits maintain a greater resistance to liquefaction than younger soil deposits. The currently available methods for assessing liquefaction potential are based on cases in which soils are of Holocene age or younger (< 10,000 yrs). The Pleistocene age soils that were tested and characterized varied in age from about 200,000 years old to 1,400,000 years old. Several sites were investigated using field methods that included the seismic cone penetration test, cone penetration test, standard penetration test, and flat plate dilatometer. Piezometers were installed at the sites. Undisturbed soil samples were retrieved from the subsurface and frozen ex situ to minimize sample disturbance during transportation and laboratory handling. The undisturbed samples were used for cyclic triaxial testing in the laboratory and were tested for shear wave velocity and compression wave velocity using in-cell transducers. Laboratory tests were performed to determine the specific gravity, grain size distribution, moisture content, unit weight, Atterberg limits, Unified Soil Classification, and visual-manual description. Optical petrography and scanning electron microscopy were used to determine the mineral content of the soils, to view grain characteristics, and to view microscopic features that were part of the soil aging process.

Laboratory index tests showed that Pleistocene soils consisted predominately of poorly-graded fine sands, silty sands, and clayey sands. Shear wave velocities from the cyclic triaxial test specimens were comparable to the in situ shear wave velocities measured using …

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 …

Distributed Sparse Signal Recovery In Networked Systems, Puxiao Han

Theses and Dissertations

In this dissertation, two classes of distributed algorithms are developed for sparse signal recovery in large sensor networks. All the proposed approaches consist of local computation (LC) and global computation (GC) steps carried out by a group of distributed local sensors, and do not require the local sensors to know the global sensing matrix. These algorithms are based on the original approximate message passing (AMP) and iterative hard thresholding (IHT) algorithms in the area of compressed sensing (CS), also known as sparse signal recovery. For distributed AMP (DiAMP), we develop a communication-efficient algorithm GCAMP. Numerical results demonstrate that it outperforms …

Modeling Radionuclide Diffusion Using Moose A Multiscale, Multiphysics Platform, Jonathon Gardner

Theses and Dissertations

Very durable ceramic waste forms have been proposed which offer longterm stability by binding certain radionuclides in their specific crystalline network. Moreover, multiple such ceramic phases can be tailored to contain specific radionuclides generated in the fuel cycle. Many such candidate ceramic forms are in the early stages of development with limited data. Modeling and simulation including modeling of diffusion can inform and provide direction to ongoing fabrication and experimental efforts. Material properties important in modeling can be obtained through laboratory measurement where available and atomistic simulation. Since diffusion occurs over multiple scales and follows multiple pathways, multiscale modeling is …

Distributed Optimization And Control Of Islanded Microgrids, Md Rishad Hossain

Theses and Dissertations

A microgrid may have numerous multi-functional power electronic converters connecting sources, loads, and storage to the system. Systems where converters are the interface between many of the main sources of energy and load centers have the ability to direct the flow of energy if the control of the converters is coordinated. The influence of energy flow in a microgrid by coordinated action of converters is referred to here as ‘energy routing’. Energy routing allows for reduction of systems losses by optimizing source operating points and reducing transmission and distribution path losses. Energy ramp rates at various points in the system …

Development Of Novel High-Throughput Methodologies To Evaluate The Thermal Stability Of High-Temperature Thin-Film Crystals For Energy Applications, Jonathan Kenneth Bunn

Theses and Dissertations

High temperature materials are used in a variety of energy applications such as jet turbines, high temperature sensors, and solid oxide fuel cells (SOFCs). Discovery of new materials and their optimization represents a difficult engineering challenge, as the materials have to be designed to have a high figure of merit during intense high temperature operations.

The large number of engineering considerations involved in the identification and optimization of such materials makes traditional one-by-one material investigations prohibitively time consuming. The time needed to explore large parameter domains can be significantly decreased through the use of high-throughput experimentation (HTE). HTE is an …