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Articles 97111 - 97140 of 197998

Full-Text Articles in Engineering

Analyzing Irrigation District Water Productivity By Benchmarking Current Operations Using Remote Sensing And Simulation Of Alternative Water Delivery Scenarios, Jonna D. Van Opstal May 2016

Analyzing Irrigation District Water Productivity By Benchmarking Current Operations Using Remote Sensing And Simulation Of Alternative Water Delivery Scenarios, Jonna D. Van Opstal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The competition for fresh water is vastly increasing particularly in semi-arid areas. Agricultural irrigation areas are urged to decrease their water use, being the largest consumer of fresh water in these areas. Improvements in irrigation management aim at increasing crop production whilst maintaining or decreasing water use. The analysis of water productivity at the irrigation district scale is challenging due to spatial heterogeneity between fields and temporal variability between growing seasons.

This dissertation makes use of satellite-based remote sensing imagery and an irrigation system simulation model to determine the water management at different spatial scales from field scale to the …


Benchmark Experiments For Natural Convection In Nuclear Fuel Rod Bundles, Kyle L. Jones May 2016

Benchmark Experiments For Natural Convection In Nuclear Fuel Rod Bundles, Kyle L. Jones

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Buoyancy is the mechanism through which heated air causes fluid motion due to a difference in temperature between a body and the surrounding fluid. This fluid motion can be very erratic and unstable, which creates a difficult problem when attempting to simulate this fluid motion. Using high performance computational power the capability of simulating these complex interactions is available but requires assessment to determine the accuracy of these difficult flow scenarios. This study provides experimental data that can be used to assess the simulation’s accuracy and to ensure the computational models are achieving the correct solution. The Rotatable Buoyancy Tunnel …


Urban Agriculture And Small Farm Irrigation: Case Studies From Cache Valley, Utah, Tyler Pratt May 2016

Urban Agriculture And Small Farm Irrigation: Case Studies From Cache Valley, Utah, Tyler Pratt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The socioeconomic landscape of water in Utah is rapidly changing due to population growth, conversion of agricultural land to urban development, and increasing awareness of future water scarcity. The Utah Division of Water Resources (DWRe) forecasts that the currently developed water supplies will not be enough to provide for Utah’s future population, and is pursuing conservation and new development to be able to meet the state’s needs.

Along with the urban growth Utah is experiencing a quickly growing sector of urban and small farm agriculture, but knowledge of water use and current practices in this area is limited. Further research …


A Risk-Based Assessment Of Agricultural Water Scarcity Under Climate Change In A Semi-Arid And Snowmelt-Dominated River Basin, Hossam Moursi May 2016

A Risk-Based Assessment Of Agricultural Water Scarcity Under Climate Change In A Semi-Arid And Snowmelt-Dominated River Basin, Hossam Moursi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Water shortage is a crucial concern in the semi-arid areas that have relatively low precipitation. Given the current situation in semi-arid areas where the water supply
already does not meet the water demand, climate change is one of the important factors that is expected to exacerbate the water shortage problem and make the situation even worse in the future. There are many indicators that prove climate change is happening, like the increasing land temperature, sea level rise and decreasing snow cover. Therefore, studying climate change impacts is a vital issue, especially its impacts on water resources systems.

In this research, …


Throttleable Gox/Abs Launch Assist Hybrid Rocket Motor For Small Scale Air Launch Platform, Zachary S. Spurrier May 2016

Throttleable Gox/Abs Launch Assist Hybrid Rocket Motor For Small Scale Air Launch Platform, Zachary S. Spurrier

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The ability for an aircraft-based launch platform to place an orbital payload onto a nominal launch trajectory at a higher energy state -- altitude, velocity, flight path angle, and azimuth --using highly-efficient air breathing propulsion instead of a much lower-efficiency rocket system, offers the potential for a significantly smaller launch vehicle. An airborne platform also provides the ability to launch from multiple locations and allows for significantly increased "system responsiveness." The NASA Armstrong Flight Research Center’s Towed Glider Air-Launch System (TGALS) is a small-scale flight research project investigating the feasibility for a remotely-piloted, towed, glider system to act as a …


Optimizing The Advanced Metering Infrastructure Architecture In Smart Grid, Alireza Ghasempour May 2016

Optimizing The Advanced Metering Infrastructure Architecture In Smart Grid, Alireza Ghasempour

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The gathered data from smart meters in current advanced metering infrastructure (AMI) of smart grid is huge. This much data causes serious challenges for reliability, performance, and scalability of smart grid. Therefore, we have investigated the scalability of different AMI architectures and proposed a scalable hybrid AMI architecture. We formulated deployment cost of different AMI architecture and used a genetic-based algorithm to minimize the deployment cost for the proposed architecture. We simulated different AMI architectures for five demographic regions and the results proved that our proposed AMI hybrid architecture has a better scalability compared to other AMI architectures.


Lateral Resistance Of H-Piles And Square Piles Behind An Mse Wall With Ribbed Strip And Welded Wire Reinforcements, Andrew I. Luna May 2016

Lateral Resistance Of H-Piles And Square Piles Behind An Mse Wall With Ribbed Strip And Welded Wire Reinforcements, Andrew I. Luna

Theses and Dissertations

Bridges often use pile foundations behind MSE walls to help resist lateral loading from seismic and thermal expansion and contraction loads. Overdesign of pile spacing and sizes occur owing to a lack of design code guidance for piles behind an MSE wall. However, space constraints necessitate the installation of piles near the wall. Full scale lateral load tests were conducted on piles behind an MSE wall. This study involves the testing of four HP12X74 H-piles and four HSS12X12X5/16 square piles. The H-piles were tested with ribbed strip soil reinforcement at a wall height of 15 feet, and the square piles …


Model Validation And Transition To Turbulence In Orbiting Culture Dishes., Jonathan Michael D. Thomas May 2016

Model Validation And Transition To Turbulence In Orbiting Culture Dishes., Jonathan Michael D. Thomas

Electronic Theses and Dissertations

Wall shear stress (WSS) is commonly accepted as the primary influence affecting characteristics of anchored endothelial cells when subjected to fluid flow. Orbital shakers are commonly used to study cellular responses due to their ease of use, ability to run several experiments simultaneously, and since they exert physiologically relevant oscillatory shear. These studies require comprehensive resolution of WSS, however the fluid dynamics inside orbiting culture dishes has not yet been well described since the flow is complex and difficult to quantify analytically. A computational fluid dynamics (CFD) model of flow in an orbiting dish has been developed that yields detailed …


Design Of An Assistive Technology Adaptive Switch Using An Inertial Measurement Unit, Ethan Storm Williams May 2016

Design Of An Assistive Technology Adaptive Switch Using An Inertial Measurement Unit, Ethan Storm Williams

Graduate Theses and Dissertations

A new assistive technology switch for people with disabilities was developed utilizing an Inertial Measurement Unit (IMU) as the sensor technology. The hardware can be customized through firmware to provide custom switch activations on a person by person basis. The firmware is customized to recognize specific data features in the IMU data which identify the desired switch activation movement performed by the user. In this way, the switch can be adapted to activate based on the movements of the user. During this research, the generic hardware platform, including the IMU sensor technology and Bluetooth communications, was designed and tested. An …


Computing Research In Academia: Classifications, Keywords, Perceptions, And Connections, Sung Han Kim May 2016

Computing Research In Academia: Classifications, Keywords, Perceptions, And Connections, Sung Han Kim

Theses and Dissertations

The Association for Computing Machinery (ACM) recognizes five computing disciplines: Computer Science (CS), Computer Engineering (CE), Information Technology (IT), Information Systems (IS), and Software Engineering (SE). Founded in 1947 the ACM is the world's largest society for computing educators, researchers, and professionals. While Computer Science has been a degree program since 1962, the other four are relatively new. This research focuses on understanding the graduate research in four of the five ACM disciplines (CS, CE, IT, and IS) using a large body of thesis and dissertation metadata. SE is not found in the metadata and graduate work in SE is …


Roadway Safety Analysis Methodology, Samuel Thomas Mineer May 2016

Roadway Safety Analysis Methodology, Samuel Thomas Mineer

Theses and Dissertations

The Utah Department of Transportation (UDOT) Traffic and Safety Division continues to advance the safety of the state roadway network through network screening and decision making tools. In an effort to aid UDOT in meeting this goal, the Department of Civil and Environmental Engineering at Brigham Young University (BYU) has worked with the Statistics Department in developing analysis tools for highway safety, specifically the Utah Crash Prediction Model (UCPM) and the Utah Crash Severity Model (UCSM). Additional tools and methodologies, such as the "Hot Spot Identification and Analysis," have been created to summarize the roadway characteristics, crash data, and possible …


Implementation Of Bim In The Municipal Plan Review Process, Liz Shantalle Ricardo Belliard May 2016

Implementation Of Bim In The Municipal Plan Review Process, Liz Shantalle Ricardo Belliard

Theses and Dissertations

Obtaining a building permit is an important step for any construction project. Whether it is for a new construction or a remodel job, the process involves a plan review performed by building officials. The purpose of this research was to explore ways in which Building Information Modeling (BIM) could be used to aid code officials during the plan review process. The objectives of the study were to determine if the level of detail in BIM was complete enough to allow a plan review to be perform accurately, to identify the extent to which architects are comfortable with using their models …


Removal Of High And Low Levels Of Ammonium From Industrial Wastewaters, Gregory Bock May 2016

Removal Of High And Low Levels Of Ammonium From Industrial Wastewaters, Gregory Bock

UNLV Theses, Dissertations, Professional Papers, and Capstones

Over 2×10^11 kilograms of ammonia are produced globally per year by the Haber-Bosch process which combines molecular hydrogen and nitrogen to synthesize ammonia. Most is used for fertilizer and agriculture while the remaining is used for other purposes including industrial processes and explosives. Explosives used in the mining industry are commonly ammonium nitrate (����4����3)-based. Excess ammonia and nitrate which can be dissolve into mine runoff water during blasting. Ammonia in mine and mineral wastewater can range from 20-110 mg/L. Ammonia is also present in several types of industrial wastewater such as caustic soda solutions used in the oil re-refining industry …


On The Scattering Of An Acoustic Plane Wave By A Soft Prolate Spheroid, Joseph Michael Borromeo May 2016

On The Scattering Of An Acoustic Plane Wave By A Soft Prolate Spheroid, Joseph Michael Borromeo

UNLV Theses, Dissertations, Professional Papers, and Capstones

This thesis solves the scattering problem in which an acoustic plane wave of propagation number K1 is scattered by a soft prolate spheroid. The interior field of the scatterer is characterized by a propagation number K2, while the field radiated by the scatterer is characterized by the propagation number K3. The three fields and their normal derivatives satisfy boundary conditions at the surface of the scatterer. These boundary conditions involve six complex parameters depending on the propagation numbers. The scattered wave also satisfies the Sommerfeld radiation condition at infinity. Through analytical methods, series representations are constructed for the interior field …


A Study On Automated Process For Extracting White Blood Cellular Data From Microscopic Digital Injured Skeletal Muscle Images, Bibek Karki May 2016

A Study On Automated Process For Extracting White Blood Cellular Data From Microscopic Digital Injured Skeletal Muscle Images, Bibek Karki

UNLV Theses, Dissertations, Professional Papers, and Capstones

Skeletal muscle injury is one of the common injuries caused by high-intensity sports activities, military related works, and natural disasters. In order to discover better therapies, it is important to study muscle regeneration process. Muscle regeneration process tracking is the act of monitoring injured tissue section over time, noting white blood cell behavior and cell-fiber relations. A large number of microscopic images are taken for tracking muscle regeneration process over multiple time instances. Currently, manual approach is widely used to analyze a microscopic image of muscle cross section, which is time consuming, tedious and buggy.

Automation of this research methodology …


Solar Energy Storage In Molten Salt Shell Structures, Nathan David Tyrrell Loyd May 2016

Solar Energy Storage In Molten Salt Shell Structures, Nathan David Tyrrell Loyd

UNLV Theses, Dissertations, Professional Papers, and Capstones

Molten salts (MS) in the 580°C range could be used to store excess energy from solar power stations and possibly from nuclear or coal. The energy can be stored up to a week in large containers at elevated temperature to generate eight hours of electricity to be used at night or during peak demand hours. This helps to reduce the fluctuation experienced at thermal solar power stations due to weather conditions. Our research supported by Office of Naval Research (ONR), presents a survey of salts to be used in molten salt technology and the design of large steel and hybrid …


Portable High Throughput Digital Microfluidics And On-Chip Bacteria Cultures, Yiyan Li May 2016

Portable High Throughput Digital Microfluidics And On-Chip Bacteria Cultures, Yiyan Li

UNLV Theses, Dissertations, Professional Papers, and Capstones

An intelligent, portable, and high throughput digital microfluidic (DMF) system is developed. Chapter 1 introduces microfluidics and DMF systems. In Chapter 2, a low-cost and high resolution capacitive-to-digital converter integrated circuit is used for droplet position detection. A field-programmable gate array FPGA is used as the integrated logic hub of the system for highly reliable and efficient control of the circuit. In this chapter a fast-fabricating PCB (printed circuit board) substrate microfluidic system is proposed. Smaller actuation threshold voltages than those previously reported are obtained. Droplets (3 µL) are actuated using 200 V, 500 Hz DC pulses. Droplet positions can …


Efficient Algorithms For Clustering Polygonal Obstacles, Sabbir Kumar Manandhar May 2016

Efficient Algorithms For Clustering Polygonal Obstacles, Sabbir Kumar Manandhar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Clustering a set of points in Euclidean space is a well-known problem having applications in pattern recognition, document image analysis, big-data analytics, and robotics. While there are a lot of research publications for clustering point objects, only a few articles have been reported for clustering a given distribution of obstacles. In this thesis we examine the development of efficient algorithms for clustering a given set of convex obstacles in the 2D plane. One of the methods presented in this work uses a Voronoi diagram to extract obstacle clusters. We also consider the implementation issues of point/obstacle clustering algorithms.


Ozonation In Water Reuse: Formation And Mitigation Of N-~Nitrosodimethylamine, Erica J. Marti May 2016

Ozonation In Water Reuse: Formation And Mitigation Of N-~Nitrosodimethylamine, Erica J. Marti

UNLV Theses, Dissertations, Professional Papers, and Capstones

Formation of N-nitrosodimethylamine (NDMA) is a substantial concern for drinking water and water reuse. NDMA, a probable human carcinogen, is formed when water is disinfected with chloramines and ozone. This research focused on three issues regarding NDMA formation and mitigation. The first issue involved understanding the compounds (i.e., precursors) present in water and wastewater that react with ozone to form NDMA. Model precursors were identified and molar yields for NDMA formation were determined. The model precursors form high amounts of NDMA with ozone, but form very little NDMA with chloramines, which means there are two distinct groups of NDMA precursors: …


Effect Of Thermal Treatment On High Temperature Deformation Of Alloy Ep-~823, Martin Milburn Lewis May 2016

Effect Of Thermal Treatment On High Temperature Deformation Of Alloy Ep-~823, Martin Milburn Lewis

UNLV Theses, Dissertations, Professional Papers, and Capstones

The objective of this research topic is to determine mechanical properties of Alloy EP-823 and to provide a mechanistic understanding of its sensitivity to both thermal treatment and performance temperature. EP-823 is a leading target material for accelerator-driven waste transmutation applications. Overall, the tensile test results of Alloy EP-823 indicated a general trend of decreasing mechanical performance with an increase in tempering time. An increase in tempering time had a statistically significant inverse relationship with ultimate tensile strength (UTS) and yield strength (YS). An increase in tempering time did not have a significant effect on elongation and reduction in area. …


Development Of Solar Experiments With Remote Laboratory Capability For Engineering Education Of The Future, Otto Kyle Neidert May 2016

Development Of Solar Experiments With Remote Laboratory Capability For Engineering Education Of The Future, Otto Kyle Neidert

UNLV Theses, Dissertations, Professional Papers, and Capstones

Educating future engineers will be handled differently as this modern society has various methods of doing so and a plethora of knowledge to pursue. The availability of computers and internet has changed many things. A subject that is relevant in today’s world but not common to most people and some engineers is solar energy. As part of a grant from the National Science Foundation that was awarded to Louisiana State University (LSU), Florida State University (FSU), and the University of Nevada, Las Vegas (UNLV), the UNLV Center for Energy Research partnered with them to create solar application based learning modules. …


Laboratory Evaluation Of Geogrid-Reinforced Flexible Pavements, Mohammadreza Sharbaf May 2016

Laboratory Evaluation Of Geogrid-Reinforced Flexible Pavements, Mohammadreza Sharbaf

UNLV Theses, Dissertations, Professional Papers, and Capstones

An experimental laboratory program to assess the effectiveness of biaxial and triaxial geogrid-reinforced flexible pavements to reduce roadway section was carried out. Six laboratory tests were conducted using a steel cylindrical mold with dimensions of 1.8 m (6 ft) in diameter and 2.1 m (7 ft) in height. The studied reinforced and unreinforced (without geogrid) sections consisted of a locally-obtained subgrade with a minimum thickness of 1.5 m (5 ft) and an asphaltic surface course of 7.6 cm (3 in). The base thickness of three tests was 30.5 cm (12 in) while for the other three tests used base thickness …


Causes Of Change Orders And Its Impact On Road Maintenance Contracts, Kabindra Kumar Shrestha May 2016

Causes Of Change Orders And Its Impact On Road Maintenance Contracts, Kabindra Kumar Shrestha

UNLV Theses, Dissertations, Professional Papers, and Capstones

Change orders (CO) commonly generate cost-growth, schedule-growth or both, in construction as well as in maintenance contracts. Literature reviews revealed that the causes and impact of CO on new construction contracts had been comprehensively studied, but the causes and impact of CO in maintenance contracts remained neglected. This study collected CO data on road maintenance contracts to determine the amount of CO and the most frequent and high-risk road maintenance activities that had CO. A Delphi study was conducted with 33 maintenance engineers from the state Department of Transportation (DOT) to identify causes of CO and its impact on cost …


Perchlorate Bioremediation: Controlling Media Loss In Ex-Situ Fluidized Bed Reactors And In-Situ Biological Reduction By Slow-Release Electron Donor, Sichu Shrestha May 2016

Perchlorate Bioremediation: Controlling Media Loss In Ex-Situ Fluidized Bed Reactors And In-Situ Biological Reduction By Slow-Release Electron Donor, Sichu Shrestha

UNLV Theses, Dissertations, Professional Papers, and Capstones

The main concern of perchlorate exposure through drinking water is its effects on the production of thyroid hormone, which is important for human metabolism and child’s brain development. The US Environmental Protection Agency (EPA) has listed perchlorate in the contaminant list as well as in the Unregulated Contaminant Monitoring rule.

The extent of perchlorate contamination can be categorized by the level of contamination into parts per million (ppm) levels, typically in locations where perchlorate was manufactured, and parts per billion (ppb) levels where perchlorate was used for various purposes. Ion-exchange is generally adopted for treating ppb levels of perchlorate while …


Synthesis And Characterization Of Graphene, Ashok Em Sudhakar May 2016

Synthesis And Characterization Of Graphene, Ashok Em Sudhakar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Graphene is an important nanoscale material with unique electronic and optical properties. Due to its many potential applications, grapheme was the subject of a Nobel Prize in physics 2010; Andre Geim and Kostya Novoselov of Manchester University received the Nobel Prize for demonstrating the ability to create single atom thick graphene layers from bulk graphite. Since then, many alternative synthesis techniques and device applications of graphene have been explored. An important and unique property of graphene is its excellent thermal properties. Graphene has a two dimensional structure and the thermal properties are significantly different than three dimensional bulk materials. Using …


Biosignatures In Mars Analog Acid Salt Lakes, Sarah Stewart Johnson, M. L. Soni, D. J. Collins, Kathleen C. Benison, Melanie R. Mormile, M. G. Chevrette, B. L. Ehlmann May 2016

Biosignatures In Mars Analog Acid Salt Lakes, Sarah Stewart Johnson, M. L. Soni, D. J. Collins, Kathleen C. Benison, Melanie R. Mormile, M. G. Chevrette, B. L. Ehlmann

Biological Sciences Faculty Research & Creative Works

Paleolake sites on Mars, particularly buried deposits that have been shielded from surface radiation, serve as intriguing targets for the search for life. Mars-like ephemeral playa lakes here on Earth can offer insights and perspectives on the possibilities for physical, metabolic, and biomolecular biosignature recovery from similar environments on Mars.


Low Cost, Carbon-Based Micro- And Nano-Structured Electrodes For High Performance Supercapacitors, Kryssia Pamela Díaz Orellana May 2016

Low Cost, Carbon-Based Micro- And Nano-Structured Electrodes For High Performance Supercapacitors, Kryssia Pamela Díaz Orellana

All Dissertations

Advances in the development of sustainable, low-cost, and reliable energy storage technologies have become a high priority as the demand for high power, and high energy storage devices has risen with emerging technologies in electronics, transportation, and renewable energy systems. Supercapacitors, due to their relatively high energy density and power density, provide an attractive alternative to bridge the gap between conventional batteries and capacitors. Materials ranging from high surface area, inert carbons to Faradaic metal oxides and conducting polymers have been used to achieve a range of performance properties in supercapacitors. However, the development of new technologies faces many challenges, …


A Backend Framework For The Efficient Management Of Power System Measurements, Benjamin Mccamish, Rich Meier, Jordan Landford, Robert B. Bass, David Chiu, Eduardo Cotilla-Sanchez May 2016

A Backend Framework For The Efficient Management Of Power System Measurements, Benjamin Mccamish, Rich Meier, Jordan Landford, Robert B. Bass, David Chiu, Eduardo Cotilla-Sanchez

Electrical and Computer Engineering Faculty Publications and Presentations

Increased adoption and deployment of phasor measurement units (PMU) has provided valuable fine-grained data over the grid. Analysis over these data can provide insight into the health of the grid, thereby improving control over operations. Realizing this data-driven control, however, requires validating, processing and storing massive amounts of PMU data. This paper describes a PMU data management system that supports input from multiple PMU data streams, features an event-detection algorithm, and provides an efficient method for retrieving archival data. The event-detection algorithm rapidly correlates multiple PMU data streams, providing details on events occurring within the power system. The event-detection algorithm …


2016 Maintenance Customer Survey, R. Clark Graves, David L. Allen May 2016

2016 Maintenance Customer Survey, R. Clark Graves, David L. Allen

Kentucky Transportation Center Research Report

The Kentucky Transportation Center, with the assistance of the University of Kentucky’s Survey Research Center, administered a telephone survey to 1,221 licensed drivers throughout the state to gauge their opinion of the Kentucky Transportation Cabinet’s (KYTC) maintenance activities. Survey respondents were distributed throughout KYTC’s 12 highway districts. The survey focused on five areas of highway maintenance: roadside features, pavement surfaces, shoulders, drainage and signs/markings. Respondents indicated they were most satisfied with the current maintenance of signs, guardrail, and striping. Pavement surfaces and potholes, and shoulders and roadway drainage, received the lowest rankings — given that the driving public is very …


Lesion Identification And The Effect Of Lesion On Motor Mapping After Stroke, Ruixi Zhou May 2016

Lesion Identification And The Effect Of Lesion On Motor Mapping After Stroke, Ruixi Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

Stroke is the most common cause of long-term severe disability and the motor system that is most commonly affected in stroke. One of the mechanisms that underlies recovery of motor deficits is reorganization or remapping of functional representations around the motor cortex. This mechanism has been shown in monkeys, but results in human subjects have been variable. In this thesis, I used a database that includes longitudinal behavioral and multimodal imaging data in both stroke patients and healthy controls for two research projects. Firstly, I improved an automatic lesion segmentation method to aid in the identification of the location and …