Engineering Commons^™

Nanomaterials For Solar Distillation Technology, Jack Warren Stoddard Cheney

UNLV Theses, Dissertations, Professional Papers, and Capstones

Water is the most important resource for mankind. Yet, 97% of the earth’s surface water is seawater in the oceans and only 3% is fresh water in ground water. Therefore, different kinds of water desalination and treatment technologies have been developed, and water distillation is a basic process of evaporating water in order to leave behind impurities such as minerals, pollutants, and other contaminants. Although distillation is known as an effective water treatment process that removes many kinds of bacteria and inorganic chemicals and heavy metals, a large amount of conventional energy and non-renewable resources are consumed for this process. …

A Distributed Processing Platform With Reconfigurable Autonomous Nodes, Grzegorz Chmaj

UNLV Theses, Dissertations, Professional Papers, and Capstones

Distributed processing is a fast growing area of interest due to the exploding popularity of Internet of Things (IoT) and Unmanned Aerial Vehicles (UAV) technologies. IoT is a distributed processing structure by nature, while UAVs evolve from single-UAV applications towards multiple-UAV (teams). The demand for processing capabilities is expanding as well. The general purpose processors (e.g. CPUs) can be used for any type of application, however this flexibility is at the cost of operational efficiency. Application Specific Integrated Circuits (ASICs) are designed for certain types of application and have great operational efficiency, but they rarely can be used for other …

The Validation And Verification Of Les Modeling Using Kiva, David Fyda

UNLV Theses, Dissertations, Professional Papers, and Capstones

In recent years, the use of large-eddy simulation (LES) has grown into new research methods. LES is preferred when compared to Reynold’s Averaged Navier Stokes (RANS), which separates velocity components into steady and fluctuating components. While RANS is relatively easy to implement, it does not fully resolve the range of turbulence eddies and has limitations that make it inaccurate in many practical circumstances. Direct numerical simulation, DNS, fully resolves all turbulent eddies to the smallest grid scale, but requires an extremely fine grid. This makes it computationally impractical to use as the computational power required to solve even the simplest …

Complex Traffic Network Modeling & Area-Wide Hierarchical Control, Saumya Gupta

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis presents a novel methodology to divide a traffic region into subregions such that in each subregion a Macroscopic Fundamental Diagram (MFD) can be used to determine the state of that subregion. The region division is based on the theory of complex networks. We exploit the inherent network characteristics through PageRank centrality algorithm to identify the most significant nodes in the traffic network. We use these significant nodes as the seeds for a Voronoi diagram based partitioning mechanism of the network. A network wide hierarchical control framework is then presented which controls these sub regions individually and the network …

Design And Implementation Of Benes/Clos On-Chip Interconnection Networks, Yikun Jiang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Networks-on-Chip (NoCs) have emerged as the key on-chip communication architecture for multiprocessor systems-on-chip and chip multiprocessors. Single-hop non-blocking networks have the advantage of providing uniform latency and throughput, which is important for cachecoherent NoC systems. Existing work shows that Benes networks have much lower transistor count and smaller circuit area but longer delay than crossbars. To reduce the delay, we propose to design the Clos network built with larger size switches. Using less than half number of stages than the Benes network, the Clos network with 4x4 switches can significantly reduce the delay. This dissertation focuses on designing high performance …

Characterization Of Impact Properties Of Forged, Layered, And Additive Manufactured Titanium Alloy, Melissa Kathryn Matthes

UNLV Theses, Dissertations, Professional Papers, and Capstones

New additive manufactured (AM) materials have the potential of optimizing the geometry and microstructure of complex components to enhance their structural integrity while creating them quickly. However, the behavior of AM materials under extreme dynamic loading conditions is not fully understood. This is especially important in many applications. For example, spacecraft components may be impacted by micrometeorites at hyper velocities of multiple kilometers per second, inducing extreme dynamic loading.

One type of AM material is created by melting and solidifying metal along a specified path. Depending on the geometry, additional streams will be deposited side-by-side. This process affects the microstructure …

Design, Fabrication And Testing Of Monolithic Low-Power Passive Sigma-Delta Analog-To-Digital Converters, Angsuman Roy

UNLV Theses, Dissertations, Professional Papers, and Capstones

Analog-to-digital converters are critically important in electronic systems. The

difficulty in meeting high performance parameters increases as integrated circuit design

process technologies advance into the deep nanometer region. Sigma-delta analog-todigital

converters are an attractive option to fulfill many data converter requirements.

These data converters offer high performance while relaxing requirements on the precision

of components within an integrated circuit. Despite this, the active integrators found within

sigma-delta analog-to-digital converters present two main challenges. These challenges are

the power consumption of the active amplifier and achieving gain-bandwidth necessary for

sigma-delta data converters in deep nanometer process technologies. Both of these

challenges …

Ionic Polymer-Metal Composite Actuators Based On Nafion Blends With Functional Polymers, Jungsoo Nam

UNLV Theses, Dissertations, Professional Papers, and Capstones

Ionic polymer metal composites (IPMCs) have been an attractive research subject for use in underwater robotic applications, biomedical and biomimetic application owing to their great potential as actuators, artificial muscles, and more. IPMC is synthetic composite nanomaterial of ion exchange membranes and metal electrode. Although both components are important, the properties of ion exchange membranes should be emphasized since it is responsible of the path for the mobile ions to migrate when voltage is applied to exhibit deformation. Most of the researches that have been done on IPMCs used commercially available Nafion as their ion exchange membranes. However, its high …

Optimizing Virtual Resource Management In Cloud Datacenters, Liuhua Chen

All Dissertations

Datacenter clouds (e.g., Microsoft's Azure, Google's App Engine, and Amazon's EC2) are emerging as a popular infrastructure for computing and storage due to their high scalability and elasticity. More and more companies and organizations shift their services (e.g., online social networks, Dropbox file hosting) to clouds to avoid large capital expenditures. Cloud systems employ virtualization technology to provide resources in physical machines (PMs) in the form of virtual machines (VMs). Users create VMs deployed on the cloud and each VM consumes resources (e.g., CPU, memory and bandwidth) from its host PM. Cloud providers supply services by signing Service Level Agreement …

Strain Energy Absorption Corresponds To Decreased Incidence Of Ventricular Fibrillation In A Commotio Cordis Model, Kayt E. Frisch, Mark S. Link, John Van Weelden

Faculty Work Comprehensive List

A healthy teenage boy is playing high school baseball, when he is struck in the chest by the ball; minutes later, his heart is experiencing ventricular fibrillation (VF) and the only way to resuscitate him is to use a defibrillator. This phenomenon, is known as Commotio Cordis (CC), and occurs as many as 20 times each year in the United States. CC most frequently occurs in sports with small balls (e.g. baseball or lacrosse) and requires a specific set of circumstances–a projectile with a certain amount of energy that impacts directly over the left ventricle of the heart during a …

Miss Lonesome: Old Boats Past Their Prime, Garth Woodruff

Faculty Publications

No abstract provided.

A Dissolution-Precipitation Mechanism Is At The Origin Of Concrete Creep In Moist Environments, Isabella Pignatelli, Aditya Kumar, R. Alizadeh, Yann Le Pape, Mathieu Bauchy, Gaurav Sant

Materials Science and Engineering Faculty Research & Creative Works

Long-term creep (i.e., deformation under sustained load) is a significant material response that needs to be accounted for in concrete structural design. However, the nature and origin of concrete creep remain poorly understood and controversial. Here, we propose that concrete creep at relative humidity ≥ 50%, but fixed moisture content (i.e., basic creep), arises from a dissolution-precipitation mechanism, active at nanoscale grain contacts, as has been extensively observed in a geological context, e.g., when rocks are exposed to sustained loads, in liquid-bearing environments. Based on micro-indentation and vertical scanning interferometry data and molecular dynamics simulations carried out on calcium-silicate-hydrate (C-S-H), …

Preface To The Special Issue On Advanced Microstructural Characterization Of Materials, Haiming Wen

Materials Science and Engineering Faculty Research & Creative Works

Microstructural characterization is a vital part in materials science, as it plays a key role in understanding the structure-property relationship in materials. Various advanced microstructural characterization techniques have emerged, for example, scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy, high resolution (scanning) transmission electron microscopy, electron backscatter diffraction, energy dispersive x-ray spectroscopy, electron energy loss spectroscopy, precession electron diffraction, energy-filtered transmission electron microscopy, and atom probe tomography. The applications of these techniques have greatly advanced the understanding of material microstructures on different scales from micrometer to atomic scale. Advanced microstructural characterization can be applied to a variety of …

Control Of Energy Density Inside A Disordered Medium By Coupling To Open Or Closed Channels, Raktim Sarma, Alexey Yamilov, Sasha Petrenko, Yaron Bromberg, Hui Cao

Physics Faculty Research & Creative Works

We demonstrate experimentally the efficient control of light intensity distribution inside a random scattering system. The adaptive wave front shaping technique is applied to a silicon waveguide containing scattering nanostructures, and the on-chip coupling scheme enables access to all input spatial modes. By selectively coupling the incident light to the open or closed channels of the disordered system, we not only vary the total energy stored inside the system by a factor of 7.4, but also change the energy density distribution from an exponential decay to a linear decay and to a profile peaked near the center. This work provides …

Stability Of The M2 Phase Of Vanadium Dioxide Induced By Coherent Epitaxial Strain, N. F. Quackenbush, Yijia Gu, For Full List Of Authors, See Publisher's Website.

Materials Science and Engineering Faculty Research & Creative Works

Tensile strain along the cR axis in epitaxial VO₂ films raises the temperature of the metal insulator transition and is expected to stabilize the intermediate monoclinic M2 phase. We employ surface-sensitive x-ray spectroscopy to distinguish from the TiO₂ substrate and identify the phases of VO₂ as a function of temperature in epitaxial VO₂/TiO₂ thin films with well-defined biaxial strain. Although qualitatively similar to our Landau-Ginzburg theory predicted phase diagrams, the M2 phase is stabilized by nearly an order of magnitude more strain than expected for the measured temperature window. Our results reveal that the …

Learning In The Real World: Constraints On Cost, Space, And Privacy, Matt J. Kusner

McKelvey School of Engineering Graduate Student Theses & Dissertations

The sheer demand for machine learning in fields as varied as: healthcare, web-search ranking, factory automation, collision prediction, spam filtering, and many others, frequently outpaces the intended use-case of machine learning models. In fact, a growing number of companies hire machine learning researchers to rectify this very problem: to tailor and/or design new state-of-the-art models to the setting at hand.

However, we can generalize a large set of the machine learning problems encountered in practical settings into three categories: cost, space, and privacy. The first category (cost) considers problems that need to balance the accuracy of a machine learning model …

Augmenting Sensorimotor Control Using “Goal-Aware” Vibrotactile Stimulation During Reaching And Manipulation Behaviors, Emmanouil Tzorakoleftherakis, Todd D. Murphey, Robert A. Scheidt

Biomedical Engineering Faculty Research and Publications

We describe two sets of experiments that examine the ability of vibrotactile encoding of simple position error and combined object states (calculated from an optimal controller) to enhance performance of reaching and manipulation tasks in healthy human adults. The goal of the first experiment (tracking) was to follow a moving target with a cursor on a computer screen. Visual and/or vibrotactile cues were provided in this experiment, and vibrotactile feedback was redundant with visual feedback in that it did not encode any information above and beyond what was already available via vision. After only 10 minutes of practice using vibrotactile …

Functional Vasodilation And Vascular Reactivity In Arteriolar Collaterals In The Spinotrapezius Of Males And Females, Britta C. Nelson

Biomedical Engineering

Peripheral arterial occlusive disease (PAOD) occurs when there is narrowing or blockage of the peripheral arteries that carry blood to the extremities, most commonly the legs. The most common symptom of PAOD is intermittent claudication, or ischemic pain during exercise. Women with PAOD experience a greater extremity functional impairment than men. Since impaired vasodilation might cause the ischemic pain from PAOD, we should evaluate vasodilation post ligation in males and females in collateral vessels, which connect two arterial segments to maintain blood flow to an otherwise hypoxic area. First, we need to examine collateral vasodilation in unoperated male and female …

A Multilingual Semi-Supervised Approach In Deriving Singlish Sentic Patterns For Polarity Detection, Siaw Ling Lo, Erik Cambria, Raymond Chiong, David Cornforth

Research Collection School Of Computing and Information Systems

Due to the huge volume and linguistic variation of data shared online, accurate detection of the sentiment of a message (polarity detection) can no longer rely on human assessors or through simple lexicon keyword matching. This paper presents a semi-supervised approach in constructing essential toolkits for analysing the polarity of a localised scarce-resource language, Singlish (Singaporean English). Corpus-based bootstrapping using a multilingual, multifaceted lexicon was applied to construct an annotated testing dataset, while unsupervised methods such as lexicon polarity detection, frequent item extraction through association rules and latent semantic analysis were used to identify the polarity of Singlish n-grams before …

Enhancing Local Search With Adaptive Operator Ordering And Its Application To The Time Dependent Orienteering Problem, Aldy Gunawan, Hoong Chuin Lau, Kun Lu

Research Collection School Of Computing and Information Systems

No abstract provided.

Value Based Methodology To Evaluate Sensors For Bridge Structural Health Monitoring Systems, Jefferson Santos De Oliveira

Theses and Dissertations

Structural health monitoring (SHM) systems have become important tools in the transportation industry to help monitor the behavior and health of civil structures. Today, there is a real concern about the health of bridges because these structures are aging, and various failure events have contributed to increase that concern. Consequently, the topic of improving the effectiveness and appropriate use of SHM systems have become the focus of various government agencies and researchers, both in industry and academia. In this context, this thesis work was developed to understand the general components of bridge SHM systems, and present a methodology to help …

Improving The Efficiency Of Ci With Uber-Commits, Matias Waterloo

School of Computing: Dissertations, Theses, and Student Research

Continuous Integration (CI) is a software engineering practice where developers break their coding tasks into small changes that can be integrated with the shared code repository on a frequent basis. The primary objectives of CI are to avoid integration problems caused by large change sets and to provide prompt developer feedback so that if a problem is detected, it can be easily and quickly resolved. In this thesis, we argue that while keeping changes small and integrating often is a wise approach for developers, the CI server may be more efficient operating on a different scale. In our approach, the …

Visualization Of Dropwise Condensation On Vertical Plate And Horizontal Tube Geometry, Blake Naccarato

UNLV Theses, Dissertations, Professional Papers, and Capstones

A droplet detection method has been developed to measure the distribution of droplet sizes on a flat plate under dropwise condensation. Dropwise condensation heat transfer may be modeled by combining an expression for the single droplet heat transfer rate with the droplet size distribution. The ability to measure this distribution is integral to the validation of such models. An example study is undertaken in which heat flux is obtained for a given surface treatment by implementing such a model and measuring the droplet size distribution. These results are compared with the heat flux measured by internal coolant temperature monitoring for …

Methamphetamine Absorption By Skin Lipids: Accumulated Mass, Partition Coefficients, And The Influence Of Fatty Acids, K. Parker, G. Morrison

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Occupants of former methamphetamine laboratories, often residences, may experience increased exposure through the accumulation of the methamphetamine in the organic films that coat skin and indoor surfaces. The objectives of this study were to determine equilibrium partition coefficients of vapor-phase methamphetamine with artificial sebum (AS-1), artificial sebum without fatty acids (AS-2), and real skin surface films, herein called skin oils. Sebum and skin oil-coated filters were exposed to vapor-phase methamphetamine at concentrations ranging from 8 to 159 ppb, and samples were analyzed for exposure time periods from 2 h to 60 days. For a low vapor-phase methamphetamine concentration range of …

Free Deterministic Equivalents For The Analysis Of Mimo Multiple Access Channel, An An Lu, Xiqi Gao, Chengshan Xiao

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, a free deterministic equivalent is proposed for the capacity analysis of the multi-input multi-output (MIMO) multiple access channel (MAC) with a more general channel model compared to previous works. In particular, a MIMO MAC with one base station (BS) equipped with several distributed antenna sets is considered. Each link between a user and a BS antenna set forms a jointly correlated Rician fading channel. The analysis is based on operator-valued free probability theory, which broadens the range of applicability of free probability techniques tremendously. By replacing independent Gaussian random matrices with operator-valued random variables satisfying certain operator-valued …

Osem : Occupant-Specific Energy Monitoring., Anand S. Kulkarni

Electronic Theses and Dissertations

Electricity has become prevalent in modern day lives. Almost all the comforts people enjoy today, like home heating and cooling, indoor and outdoor lighting, computers, home and office appliances, depend on electricity. Moreover, the demand for electricity is increasing across the globe. The increasing demand for electricity and the increased awareness about carbon footprints have raised interest in the implementation of energy efficiency measures. A feasible remedy to conserve energy is to provide energy consumption feedback. This approach has suggested the possibility of considerable reduction in the energy consumption, which is in the range of 3.8% to 12%. Currently, research …

Microfluidic Platform For Impedance Characterization Of Endothelial Cells Under Fluid Shear Stress., Vanessa Velasco

Electronic Theses and Dissertations

Endothelium dysfunction has been associated with many pathophysiological processes leading to cardiovascular diseases. Studying endothelium behavior is vital to understand the onset, prevention, and treatment of such diseases. Electrical impedance spectroscopy has been shown to provide a real-time in vitro evaluation of cell behavior including cell monolayer permeability. However, the majority of published work has been primarily with static cell culture models or macro-scale models that do not properly represent the physiological sizes, structures, and environmental conditions of human blood vessels. Within this dissertation, the design, fabrication, characterization, and application of a microfluidic impedance platform is presented for the in …

A Non-Invasive Diagnostic System For Early Assessment Of Acute Renal Transplant Rejection., Mohamed Nazih Mohamed Ibrahim Shehata

Electronic Theses and Dissertations

Early diagnosis of acute renal transplant rejection (ARTR) is of immense importance for appropriate therapeutic treatment administration. Although the current diagnostic technique is based on renal biopsy, it is not preferred due to its invasiveness, recovery time (1-2 weeks), and potential for complications, e.g., bleeding and/or infection. In this thesis, a computer-aided diagnostic (CAD) system for early detection of ARTR from 4D (3D + b-value) diffusion-weighted (DW) MRI data is developed. The CAD process starts from a 3D B-spline-based data alignment (to handle local deviations due to breathing and heart beat) and kidney tissue segmentation with an evolving geometric (level-set-based) …

2016 Safety Belt Usage Survey In Kentucky, Kenneth R. Agent, Eric R. Green, Michael A. Fields

Kentucky Transportation Center Research Report

The use of safety belts and child safety seats is a proven means of reducing injuries to motor vehicle occupants involved in traffic crashes. There have been various methods used in efforts to increase safety belt and safety seat usage. Past efforts have included public information campaigns, local and statewide legislation, and enforcement of the legislation.

The objective of the survey summarized in this report was to establish a statewide safety belt usage rate in Kentucky for 2016. This rate can be compared to those determined from previous surveys. The 2016 statewide survey documents the continued increase in usage associated …

Synthesis Of Kentucky’S Traveler Information Systems, Christopher W. Van Dyke, Jennifer R. Walton, James Ballinger

Kentucky Transportation Center Research Report

After the United States Department of Transportation (USDOT) petitioned the Federal Communications Commission (FCC) to establish a dedicated phone number for real-time travel information services, the abbreviated 511 dialing code was founded in July 2000. The FCC reasoned that 511 services could reduce traffic congestion, air pollution, and the inefficient use of fossil fuels. 511 would, in turn, improve traveler safety. In 2010, the Federal Highway Administration (FHWA) mandated a set of requirements for systems that deliver real-time traffic information to the public. States DOTs were asked to comply with this mandate by November 2014. Many states, in addition to …