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Articles 1951 - 1980 of 2844

Full-Text Articles in Engineering

Eveleth, Minnesota: A Portrait Of My Home Town, Judith I. Luna Dec 2016

Eveleth, Minnesota: A Portrait Of My Home Town, Judith I. Luna

Graduate Theses and Dissertations

This 30-minute documentary film provides snapshots of the small northeastern iron mining town of Eveleth, Minnesota, on the Mesabi Iron Range. It uses a two-pronged approach: 1) a first-person return to the town by the filmmaker almost 50 years after graduating from high school to see how the town may have changed, 2) a look at some historical and cultural factors which made the town what it was when the filmmaker was growing up and what continues to animate the town in the face of iron mining’s decline and rebirth. The latter include the immigrant experience and influence as the …


Wells Fargo, Samsung And Spacex: The Dos And Don’Ts Of Today’S Quality Environment, Jim Burgin Nov 2016

Wells Fargo, Samsung And Spacex: The Dos And Don’Ts Of Today’S Quality Environment, Jim Burgin

Operations Management Presentations

Quality is everywhere, and is so critical to your success. This webinar will use Toyota’s 14 Principles as the springboard to discuss teach points from my Quality Management class. The title mentions a few companies where good practices or challenging activities provide a road map to success or failure. Rest assured there are many more. Burgin uses stories and experiences from class to illustrate quality concepts.


The Role Of Organic Matter In The Fate And Transport Of Antibiotic Resistance, Metals, And Nutrients In The Karst Of Northwest Arkansas, Victor Lee Roland Ii Aug 2016

The Role Of Organic Matter In The Fate And Transport Of Antibiotic Resistance, Metals, And Nutrients In The Karst Of Northwest Arkansas, Victor Lee Roland Ii

Graduate Theses and Dissertations

Organic matter (OM) in the environment acts as a nutrient, but may also act as a transport vector for harmful chemical compounds and bacteria. Acetate is a labile form of OM produced during fermentation in anaerobic lagoons used to store animal fecal-waste from concentrated animal feeding operations (CAFOs). Dry and liquid fertilizers from CAFOs pose a threat to groundwater by introducing excessive amounts of nutrients (e.g. OM, nitrate and ammonia), metals, and antibiotic compounds. In the epikarst of Northern Arkansas in the Buffalo River watershed additional input of labile dissolved organic carbon (DOC) from liquid CAFO waste-fertilizers was hypothesized to …


Asbestos Cement Pipe Condition Assessment And Remaining Service Life Prediction, Abiy Melles Ghirmay Aug 2016

Asbestos Cement Pipe Condition Assessment And Remaining Service Life Prediction, Abiy Melles Ghirmay

Graduate Theses and Dissertations

This research details a condition assessment of asbestos cement (AC) pipe within in the Bella Vista Village Property Owners Association water distribution system. Bella Vista Village contains appropriately 300 miles of AC pipe with nominal diameters from 6-14 inch. The goal of the research is to determine the current condition of AC pipe within the system and predict future performance of the pipes. AC pipe samples were obtained from 23 locations disturbed across the distribution system with nominal pipe diameters of 6-8 inch. Estimates of current level of degradation were obtained using phenolphthalein staining and hardness measurements of each sample. …


4d Printing Dielectric Elastomer Actuator Based Soft Robots, Jiyu Cai Aug 2016

4d Printing Dielectric Elastomer Actuator Based Soft Robots, Jiyu Cai

Graduate Theses and Dissertations

4D printing is an emerging technology that prints 3D structural smart materials that can respond to external stimuli and change shape over time. 4D printing represents a major manufacturing paradigm shift from single-function static structures to dynamic structures with highly integrated functionalities. Direct printing of dynamic structures can provide great benefits (e.g., design freedom, low material cost) to a wide variety of applications, such as sensors and actuators, and robotics. Soft robotics is a new direction of robotics in which hard and rigid components are replaced by soft and flexible materials to mimic mechanisms that works in living creatures, which …


Essays On Optimization And Modeling Methods For Reliability And Reliability Growth, Thomas Paul Talafuse Aug 2016

Essays On Optimization And Modeling Methods For Reliability And Reliability Growth, Thomas Paul Talafuse

Graduate Theses and Dissertations

This research proposes novel solution techniques in the realm of reliability and reliability growth. We first consider a redundancy allocation problem to design a system that maximizes the reliability of a complex series-parallel system comprised of components with deterministic reliability. We propose a new meta-heuristic, inspired by the behavior of bats hunting prey, to find component allocation and redundancy levels that provide optimal or near-optimal system reliability levels. Each component alternative has an associated cost and weight and the system is constrained by cost and weight factors. We allow for component mixing within a subsystem, with a pre-defined maximum level …


Investigation Of Cnt-Induced Escherichia Coli Lysis And Protein Release, Abdollah Mosleh Aug 2016

Investigation Of Cnt-Induced Escherichia Coli Lysis And Protein Release, Abdollah Mosleh

Graduate Theses and Dissertations

This research investigated the use of carbon nanotubes (CNTs) as a treatment to increase the permeability of a bacterial cell wall. Recombinant Escherichia coli BL21 (DE3) containing a plasmid that expressed Green Fluorescent Protein (GFP) and -lactamase were exposed to CNTs under various levels of agitation for different times. Fluorescence assay for GFP, optical absorbance for -lactamase activity, and Transmission Electron Microscopy (TEM) were used to determine the amount of released protein, and visually examine the permeability enhancement of the cells, respectively. It was found that more -lactamase was present in the culture fluid after treatment with CNTs in a …


Photoluminescence Measurement On Low-Temperature Metal Modulation Epitaxy Grown Gan, Yang Wu Aug 2016

Photoluminescence Measurement On Low-Temperature Metal Modulation Epitaxy Grown Gan, Yang Wu

Graduate Theses and Dissertations

A low-temperature photoluminescence (PL) study was conducted on low-temperature metal modulation epitaxy (MME) grown GaN. By comparing the PL signal from high temperature grown GaN buffer layers, and MME grown cap layers on top of the buffer layers, it was found that MME grown GaN cap has a significantly greater defect-related emission. The band edge PL from MME grown GaN found to be 3.51eV at low temperature. The binding energy of the exciton in GaN is determined to be 21meV through temperature dependence analysis. A PL peak at 3.29eV was found in the luminescence of the MME grown cap layer, …


Modeling And Simulation Of 1700 V 8 A Genesic Superjunction Transistor, Staci E. Brooks Aug 2016

Modeling And Simulation Of 1700 V 8 A Genesic Superjunction Transistor, Staci E. Brooks

Graduate Theses and Dissertations

The first-ever 1.7kV 8A SiC physics-based compact SPICE model is developed for behavior prediction, modeling and simulation of the GeneSiC “Super” Junction Transistor. The model implements Gummel-Poon based equations and adds a quasi-saturation collector series resistance representation from a 1.2 kV, 6 A SiC bipolar junction transistor model developed in Hangzhou, China. The model has been validated with the GA08JT17-247 device data representing both static and dynamic characteristics from GeneSiC. Parameter extraction was performed in IC-CAP and results include plots showing output characteristics, capacitance versus voltage (C-V), and switching characteristics for 25 °C, 125 °C, and 175 °C temperatures.


Chlorine Demand Shows Thresholds And Hierarchy With Source Water Quality At Beaver Lake, Arkansas, Jaime M. Gile Aug 2016

Chlorine Demand Shows Thresholds And Hierarchy With Source Water Quality At Beaver Lake, Arkansas, Jaime M. Gile

Graduate Theses and Dissertations

This study investigated the effects of source water quality in Beaver Lake on the amount of chlorine (Cl) needed to develop decision support system to help guide chlorination practices in pre-treatment of source water. Chlorine demand assays were performed on water samples from Beaver Lake collected from the intake structure at Beaver Water District from March 2014 through August 2015, and using data from these assays, the two points of interest in this study were the Cl dose at which Cl residuals began to accumulate and the mean Cl demand occurring after that dose. Three methods of analysis were used …


Asynchronous Data Processing Platforms For Energy Efficiency, Performance, And Scalability, Liang Men Aug 2016

Asynchronous Data Processing Platforms For Energy Efficiency, Performance, And Scalability, Liang Men

Graduate Theses and Dissertations

The global technology revolution is changing the integrated circuit industry from the one driven by performance to the one driven by energy, scalability and more-balanced design goals. Without clock-related issues, asynchronous circuits enable further design tradeoffs and in operation adaptive adjustments for energy efficiency. This dissertation work presents the design methodology of the asynchronous circuit using NULL Convention Logic (NCL) and multi-threshold CMOS techniques for energy efficiency and throughput optimization in digital signal processing circuits. Parallel homogeneous and heterogeneous platforms implementing adaptive dynamic voltage scaling (DVS) based on the observation of system fullness and workload prediction are developed for balanced …


Design And Analysis Of An Asynchronous Microcontroller, Michael Hinds Aug 2016

Design And Analysis Of An Asynchronous Microcontroller, Michael Hinds

Graduate Theses and Dissertations

This dissertation presents the design of the most complex MTNCL circuit to date. A fully functional MTNCL MSP430 microcontroller is designed and benchmarked against an open source synchronous MSP430. The designs are compared in terms of area, active energy, and leakage energy. Techniques to reduce MTNCL pipeline activity and improve MTNCL register file area and power consumption are introduced. The results show the MTNCL design to have superior leakage power characteristics. The area and active energy comparisons highlight the need for better MTNCL logic synthesis techniques.


Trend Analysis Of Water Quality In Northwest Arkansas Streams Reflects Changes In The Watershed, Zachary Paul Simpson Aug 2016

Trend Analysis Of Water Quality In Northwest Arkansas Streams Reflects Changes In The Watershed, Zachary Paul Simpson

Graduate Theses and Dissertations

Watershed export of nutrients, sediments, and chemicals impacts receiving waters. Changes within the watershed (e.g., anthropogenic or climatic) can alter the transport of constituents in streams. Stream monitoring is crucial for understanding these effects. This study developed a potential improvement to flow-adjusting constituent concentrations in streams, an important step of analyzing monitoring data in lotic systems for trends. The method incorporates a K-fold cross-validation procedure to optimize a model explaining the relationship between the concentration and streamflow, thus providing a valuable tool to researchers in water quality. Additionally, two case studies were conducted on watersheds located in northwest Arkansas using …


Evaluating A Measure-Calculate Method For Determining Sediment Oxygen Demand In Lakes, Adrian Beirise Aug 2016

Evaluating A Measure-Calculate Method For Determining Sediment Oxygen Demand In Lakes, Adrian Beirise

Graduate Theses and Dissertations

A steady-state mass diffusion model used with simple measurable and calculable inputs for determining sediment oxygen demand (SOD) is compared to an intact core incubation (ICI) SOD method using samples from three lakes. The mass diffusion model coupled with inputs is known as the measure-calculate method (M-C) and is a potential alternative to existing methods for measuring SOD which are more complex, time-consuming, and costly. The M-C method requires inputs for volumetric sediment oxygen uptake (Ṅsed), sediment density and porosity, and water properties. Ṅsed was determined by suspending sediment in oxygen-saturated water with a DO probe and determining the steady …


Study Of Plasmonic Properties Of The Gold Nanorods In The Visible To Near Infrared Light Regime, Pijush Kanti Ghosh Aug 2016

Study Of Plasmonic Properties Of The Gold Nanorods In The Visible To Near Infrared Light Regime, Pijush Kanti Ghosh

Graduate Theses and Dissertations

Nanostructures of noble metals show unique plasmonic behavior in the visible to near-infrared light range. Gold nanostructures exhibit a particularly strong plasmonic response for these wavelengths of light. In this study we have investigated optical enhancement and absorption of gold nanorods with different thickness using finite element method simulations. This study reports on the resonance wavelength of the sharp-corner and round-corner rectangles of constant length 100 nm and width 60 nm. The result shows that resonance wavelength depends on the polarization of the incident light; there also exists a strong dependence of the optical enhancement and absorption on the thickness …


Electrodeionization Versus Electrodialysis: A Clean-Up Of Produced Water In Hydraulic Fracturing, Brigitte Marie Rodgers Aug 2016

Electrodeionization Versus Electrodialysis: A Clean-Up Of Produced Water In Hydraulic Fracturing, Brigitte Marie Rodgers

Graduate Theses and Dissertations

Electrodeionization (EDI) is a widely studied process ranging from applications in wastewater clean-up in the food and beverage industry to purifying organic compounds. To date, there are no apparent studies on applying this technology to produced wastewater recovered from hydraulic fracking sites. Water consumption within hydraulic fracturing sites can reach in the upwards of millions of gallons per site, so a need for a water recycling process becomes necessary within areas where water requirements are scarce. Implementation of an EDI module that is capable of handling high salt solutions from produced wastewater in subsequent fracturing practices will decrease overall water …


Initial Structural Subsidence As Reflected In Morrowan And Atokan (Pennsylvanian) Subsurface Stratigraphy, Northern Arkoma Basin, North-Central Arkansas, Fatimah Taher Nahi Al Asadi Aug 2016

Initial Structural Subsidence As Reflected In Morrowan And Atokan (Pennsylvanian) Subsurface Stratigraphy, Northern Arkoma Basin, North-Central Arkansas, Fatimah Taher Nahi Al Asadi

Graduate Theses and Dissertations

The Arkoma Basin is a carboniferous foreland basin that is known for its prolific gas production. The objective of this research is to study the initial subsidence of the basin by analyzing the strati-graphic and structural features of the study area. This was accomplished through IHS Petra, Surf-er 13, and Win-Tensor software. Field work studies comprised a large part of this study. Also, a seismic profile and Google earth elevation profiles are among the methods used to study the initial subsidence of the Arkoma Basin. The study area within the basin represents a transitional zone from the shelf into the …


Modeling Economic Impacts Of The Inland Waterway Transportation System, Furkan Oztanriseven Aug 2016

Modeling Economic Impacts Of The Inland Waterway Transportation System, Furkan Oztanriseven

Graduate Theses and Dissertations

The inland waterway transportation system of the United States (U.S.) handles 11.7 billion tons of freight annually and connects the heartland of the U.S. with the rest of the world by providing a fuel-efficient and environmentally friendly mode of transportation. This dissertation aims to create decision support tools for maritime stakeholders to measure the economic impacts of the inland waterway transportation systems under real world scenarios including disruptions, demand changes, port expansion decisions, and channel deepening investments. Monte Carlo simulation, system dynamics, discrete-event simulation, agent-based modeling, and multiregional input-output modeling techniques are utilized to analyze the complex relationships between inland …


Channel Estimation Overhead Reduction For Downlink Fdd Massive Mimo Systems, Abderrahmane Mayouche Aug 2016

Channel Estimation Overhead Reduction For Downlink Fdd Massive Mimo Systems, Abderrahmane Mayouche

Graduate Theses and Dissertations

Massive multiple-input multiple-output (MIMO) is the concept of deploying a very large number of antennas at the base stations (BS) of cellular networks. Frequency-division duplexing (FDD) massive MIMO systems in the downlink (DL) suffer significantly from the channel estimation overhead. In this thesis, we propose a minimum mean square error (MMSE)-based channel estimation framework that exploits the spatial correlation between the antennas at the BS to reduce the latter overhead. We investigate how the number of antennas at the BS affects the channel estimation error through analytical and asymptotic analysis. In addition, we derive a lower bound on the spectral …


Incorporating A New Class Of Uncertainty In Disaster Relief Logistics Planning, Emre Kirac Aug 2016

Incorporating A New Class Of Uncertainty In Disaster Relief Logistics Planning, Emre Kirac

Graduate Theses and Dissertations

In recent years, there has been a growing interest among emergency managers in using Social data in disaster response planning. However, the trustworthiness and reliability of posted information are two of the most significant concerns, because much of the user-generated data is initially not verified. Therefore, a key tradeoff exists for emergency managers when considering whether to incorporate Social data in disaster planning efforts. By considering Social data, a larger number of needs can be identified in a shorter amount of time, potentially enabling a faster response and satisfying a class of demand that might not otherwise be discovered. However, …


Compact Modeling Of Sic Insulated Gate Bipolar Transistors, Sonia Perez Aug 2016

Compact Modeling Of Sic Insulated Gate Bipolar Transistors, Sonia Perez

Graduate Theses and Dissertations

This thesis presents a unified (n-channel and p-channel) silicon/silicon carbide Insulated Gate Bipolar Transistor (IGBT) compact model in both MAST and Verilog-A formats. Initially, the existing MAST model mobility equations were updated using recently referenced silicon carbide (SiC) data. The updated MAST model was then verified for each device tested. Specifically, the updated MAST model was verified for the following IGBT devices and operation temperatures: n-channel silicon at 25 ˚C and at 125 ˚C; n-channel SiC at 25 ˚C and at 175 ˚C; and p-channel SiC at 150 ˚C and at 250 ˚C. Verification was performed through capacitance, DC output …


Go With The Flow –Thermoelectric Energy, Shawn Bell Jul 2016

Go With The Flow –Thermoelectric Energy, Shawn Bell

Middle School Lesson Plans

In this unit, students will learn how thermal energy be transferred and transformed. They will carry out investigations to gather evidence to support an explanation about direct conversion of heat into electrical energy. They will develop a model that shows the components of the system and changes in the system being investigated, and they will use evidence from the investigation to construct an explanation for how the energy flows.


Bluetooth Low Energy Platform With Simblee, Calvin W. Freeman May 2016

Bluetooth Low Energy Platform With Simblee, Calvin W. Freeman

Computer Science and Computer Engineering Undergraduate Honors Theses

Bluetooth Low Energy provides a platform for many developers to implement low power communication for a wide range of applications. The Internet of Things (IoT) is an emerging concept that is gaining traction in the world of embedded systems. Bluetooth Low Energy is one of the latest enablers of this movement and the Simblee module improves BLE accessibility. This thesis provides an evaluation of the average power consumption the Simblee uses in different use cases. By leveraging one of the Simblee’s most notable features, the Ultra Low Power mode, very low power consumption can be achieved, potentially increasing battery life …


Using Value-Focused Thinking For Engineered Resilient Systems, Colin A. Small May 2016

Using Value-Focused Thinking For Engineered Resilient Systems, Colin A. Small

Industrial Engineering Undergraduate Honors Theses

The DoD needs their systems to be resilient in the face of an ever changing world. To increase resilience in future systems the DoD has created a program called Engineered Resilient Systems. Resilience can be broken down into two parts, mission and platform resilience. Mission resilience is the ability of a system to repel, resist, absorb, and recover from environments and threats that occur on planned missions. Platform resilience is the ability of a system platform to adapt to new missions and new threats.

The University of Arkansas department of Industrial Engineering is working for the ERS program researching resilience. …


Smart Gate Driver Design For Silicon (Si) Igbts And Silicon-Carbide (Sic) Mosfets, Abdulaziz Alghanem May 2016

Smart Gate Driver Design For Silicon (Si) Igbts And Silicon-Carbide (Sic) Mosfets, Abdulaziz Alghanem

Electrical Engineering Undergraduate Honors Theses

The design of an efficient and smart gate driver for a Si IGBT and SiC MOSFET is addressed in thesis. First, the main IGBT parameters are evaluated thoroughly in order to understand their effects in the design of the gate driver. All known consequences of previously designed gate drivers are studied in order to achieve an optimum gate driver. As a result of this assessment, the designer is able to determine whether adding or removing components from the gate driver circuit are beneficial or not. Then, exhaustive research is done to identify suitable integrated circuits to use for the power …


Multiphoton Imaging Of Labeled Breast Cancer Cells To Quantify Intra And Extracellular Receptors, Sydney C. Wiggins May 2016

Multiphoton Imaging Of Labeled Breast Cancer Cells To Quantify Intra And Extracellular Receptors, Sydney C. Wiggins

Biomedical Engineering Undergraduate Honors Theses

Every year 200,000 women in the United States are diagnosed with breast cancer. Of the cases diagnosed, 10% -15% are classified as triple negative breast cancer (TNBC) due to the absence of estrogen, progesterone, and HER-2/Neu receptors. This breast cancer sub-type is markedly more aggressive and twice as likely to develop in premenopausal women. TNBC is resistant to endocrine therapies and current targeted agents, making clinical need for the development of validated therapeutics for TNBC a pressing matter. To initiate drug development, the internalization of directly immunolabeled epidermal growth factor receptors (EGFR) in SK-BR-3 human breast adenocarcinoma cells was quantitated …


Design Of Smartseat Car Seat Safety System To Prevent Child Vehicular Heat Stroke, Alexis D. Lamott May 2016

Design Of Smartseat Car Seat Safety System To Prevent Child Vehicular Heat Stroke, Alexis D. Lamott

Electrical Engineering Undergraduate Honors Theses

Child vehicular heatstroke deaths continue to be a preventable accident seen yearly. As such, a proposed safety system has been designed to monitor environmental temperatures and weight in an infant seat, to alert guardians that a young child is at risk of child vehicular heatstroke death or serious heatstroke related injury. The SmartSeat system is comprised of three separate printed circuit boards that work in unison to form the overall system.


Validation Of An Internal Camera Based Volume Determination System For Triaxial Testing, Leah D. Miramontes May 2016

Validation Of An Internal Camera Based Volume Determination System For Triaxial Testing, Leah D. Miramontes

Civil Engineering Undergraduate Honors Theses

Accurate strain and volume measurements are critical to phase relationships and strength determination for saturated and unsaturated soils. In recent years, laboratory-based photographic techniques of monitoring soil specimens have become more common. These techniques have been used to reconstruct 3D models and to determine strain and volumetric changes of triaxial specimens. A new technique that utilized digital photographs of the soil specimen, captured from within a triaxial testing cell, was utilized. Photographs were processed using photogrammetry software to reconstruct 3D models of the soil specimens. By placing camera equipment within the cell, the technique eliminated the need to account for …


Inferring Intrinsic Beliefs Of Digital Images Using A Deep Autoencoder, Seok H. Lee May 2016

Inferring Intrinsic Beliefs Of Digital Images Using A Deep Autoencoder, Seok H. Lee

Computer Science and Computer Engineering Undergraduate Honors Theses

Training a system of artificial neural networks on digital images is a big challenge. Often times digital images contain a large amount of information and values for artificial neural networks to understand. In this work, the inference model is proposed in order to absolve this problem. The inference model is composed of a parameterized autoencoder that endures the loss of information caused by the rescaling of images and transition model that predicts the effect of an action on the observation. To test the inference model, the images of a moving robotic arm were given as the data set. The inference …


Design Of Processing Circuitry For An Rf Energy Harvester, Brett Schauwecker May 2016

Design Of Processing Circuitry For An Rf Energy Harvester, Brett Schauwecker

Electrical Engineering Undergraduate Honors Theses

Significant advancements in technology and the use of low power sensors in both commercial and industrial applications have made it essential to develop wireless solutions for low power devices. Once such solution, which has generated attention in university and R&D environments, is radio frequency (RF) energy harvesting. RF energy harvesting seeks to capture ambient RF energy by means of an antenna and convert this energy to useable DC power. The presence of ambient RF energy in the environment is a result of numerous high-frequency technologies including Wi-Fi, cell phones, microwave ovens, and radio broadcasting, as well as many others. The …