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Atmospheric Water Vapor Lidar Measurements Using Analog And Photon Counting Techniques, Anuj Maheshkumar Shah

Electrical & Computer Engineering Theses & Dissertations

Atmospheric water vapor measurements are essential for the understanding of Earth's weather and radiation budget, along with the water cycle. The remote sensing Differential Absorption Lidar (DIAL) technique is a commanding method used for water vapor measurements from aircraft, spaceborne, and ground-based platforms. The new unmanned aerial vehicle (UAV) water vapor DIAL system provides great feasibility due to the weight and size limitations. The system has significantly less weight, power consumption, and noise presence, thus making it great for UAV applications.

This thesis discusses a UAV water vapor DIAL system that was designed, developed, and evaluated. The research effort was …

Piezoelectric Sensor In The Application Of Rolling Bearing Health Monitoring, Yinyin Liu

Mechanical & Aerospace Engineering Theses & Dissertations

A condition-based monitoring concept for rolling element bearings in machinery utilizing a piezoelectric load sensor is investigated in this thesis. The radially polarized cylindrical piezoelectric sensor is modeled in its specific coordinates. The sensor registers the stress occurring in all directions around it. The sensor's behavior due to several typical loads is analyzed. Based on the induced stresses in the sensor, the sensor's output as an electric charge can be obtained using the method of integration.

Considering both the normal and tangential loads distributed on the rolling beating's roller-raceway contact surface, the dynamic stress distribution in the outer raceway was …

Applicability Of Risk-Based Management And The Need For Risk-Based Economic Decision Analysis At Hazardous Waste Contaminated Sites, I. Khadam, Jagath J. Kaluarachchi

Civil and Environmental Engineering Faculty Publications

Decision analysis in subsurface contamination management is generally carried out through a traditional engineering economic viewpoint. However, new advances in human health risk assessment, namely, the probabilistic risk assessment, and the growing awareness of the importance of soft data in the decision-making process, require decision analysis methodologies that are capable of accommodating non-technical and politically biased qualitative information. In this work, we discuss the major limitations of the currently practiced decision analysis framework, which evolves around the definition of risk and cost of risk, and its poor ability to communicate risk-related information. A demonstration using a numerical example was conducted …

Study Of Geometric Effects On Local Corrosion Rates For Lbe Loop, Chao Wu

UNLV Theses, Dissertations, Professional Papers, and Capstones

Corrosion is an extremely important issue in nuclear cooling system applications. Many scientific and engineering efforts have been contributed to the research of finding an ideal material, which has resistance to corrosive Lead Bismuth Eutectic (LBE). A Delta Loop was designed and constructed in Los Alamos National Lab (LANL) to obtain the experimental data. This loop is a multi-section closed system that differs in diameter from one part to another. As a result, an intensive study on the geometry effect is hence necessary and valuable. In this thesis, this problem was simulated by commercial software STAR-CD. Results provide a good …

Analytical Ise Calculation And Optimum Control System Design, Tony Kealy, Aidan O'Dwyer

Conference papers

Abstract – In control system theory, a performance index is a quantitative measure of the performance of a system and is chosen so that emphasis is given to the important system parameters. In this paper, the authors demonstrate two methods to determine analytically the Integral of the Square of the Error (ISE) performance index value for a first-order-plus-dead-time (FOPDT) process model under PI control. The ability of proportional/integral (PI) and proportional/integral/derivative (PID) controllers to compensate most practical industrial processes has led to their wide acceptance in industrial applications. The most direct way to set up PI/PID controller parameters is the …

Progress In Spectroscopic Ellipsometry: Applications From Vacuum Ultraviolet To Infrared, James N. Hilfiker, Corey L. Bungay, Ron A. Synowicki, Thomas E. Tiwald, Craig M. Herzinger, Blaine Johs, Greg K. Pribil, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Spectroscopic ellipsometry (SE) is a noncontact and nondestructive optical technique for thin film characterization. In the past 10 yr, it has migrated from the research laboratory into the semiconductor, data storage, display, communication, and optical coating industries. The wide acceptance of SE is a result of its flexibility to measure most material types: dielectrics, semiconductors, metals, superconductors, polymers, biological coatings, and even multilayers of these materials. Measurement of anisotropic materials has also made huge strides in recent years. Traditional SE measurements cover the ultraviolet, visible, and near infrared wavelengths. This spectral range is now acquired within seconds with high accuracy …

Highway Crash Site Management, Monica L. Barrett, Jennifer R. Walton

Kentucky Transportation Center Research Report

Traveler delay is the problem most often associated with highway crashes, but by far the most serious problem is the resulting secondary crashes that occur. Another related issue is the danger posed to response personnel serving the public at the scene of a crash. The longer a crash is in place, the longer the responders are vulnerable and exposed to injury.

The Kentucky Transportation Center, in cooperation with the Kentucky Transportation Cabinet, developed a checklist and interagency workshop to address ways to secure and coordinate the resources necessary to restore the roadway’s operation in a safe and timely manner. The …

Photonic Crystals: Modeling And Simulation, Shangping Guo

Electrical & Computer Engineering Theses & Dissertations

Photonic crystals are periodic electromagnetic media in optical wavelength scale. They possess photonic band gaps (PBGs) that inhibit the existence of light within the crystals in certain wavelength range. Such band gaps produce many interesting optical phenomena. In this dissertation, the frequency (plane wave method, PWM) and time domain (finite difference time domain method, FDTD) methods are developed for their modeling and simulation.

The theory and algorithm of plane wave method are studied in detail and implemented in a unique and efficient approach. PWM is used to obtain the gap and mode information of ideal and defective photonic crystals. Several …

Optical Communications By Frequency Content Of Femtosecond Laser Pulses, Dennis Alexander, Mark L. Rohlfs

Department of Electrical and Computer Engineering: Faculty Publications

A free-space optical communications System is provided capable of transmitting data over long distances through the atmosphere. The communications System according to the present invention comprises an optical transmitter at a first location, the optical transmitter comprising a femtosecond pulsed laser Source for producing a train of femtosecond laser pulses. The optical transmitter further comprises a laser pulse width modulator to provide a pulse width modulated train of femtosecond laser pulses corresponding to the data being transmitted. The communications System further com prises an optical receiver at a Second location for receiving the modulated train of femtosecond laser pulses. The …

Identification Of Macro- And Micro-Compliant Mechanism Configurations Resulting In Bistable Behavior, Brian D. Jensen

Theses and Dissertations

The purpose of this research is to identify the configurations of several mechanism classes which result in bistable behavior. Bistable mechanisms have use in many applications, such as switches, clasps, closures, hinges, and so on. A powerful method for the design of such mechanisms would allow the realization of working designs much more easily than has been possible in the past. A method for the design of bistable mechanisms is especially needed for micro-electro-mechanical systems (MEMS) because fabrication and material constraints often prevent the use of simple, well-known bistable mechanism configurations. In addition, this knowledge allows designers to take advantage …

A Self-Retracting Fully-Compliant Bistable Micromechanism, Nathan D. Masters

Theses and Dissertations

The purpose of this research is to present a class of Self-Retracting Fully-compliant Bistable Micromechanisms (SRFBM). Fully-compliant mechanisms are needed to overcome the inherent limitations of microfabricated pin joints, especially in bistable mechanisms. The elimination of the clearances associated with pin joints will allow more efficient bistable mechanisms with smaller travel. Small travel, in a linear path facilitates integration with efficient on-chip actuators. Tensural pivots are developed and used to deal with the compressive loading to which the mechanism is subject. SRFBM are modeled using the Pseudo-Rigid-Body Model and finite element analysis. Suitable configurations of the SRFBM concept have been …

Development Of In-Plane Compliant Bistable Microrelays, Troy Alan Gomm

Theses and Dissertations

Bistable microrelays have many possible applications and have the potential to reduce the size, weight, power consumption, and cost of products in which they are used. This research outlines the current state of microrelays, presents three new compliant bistable micromechanisms, and characterizes their performance as microrelays. The characterization includes a treatment of a new force-tester, a preliminary contact resistance study, contact-force measurements, switching time measurements, insertion loss, AC isolation, breakdown voltage, and DC isolation. This document also includes recommendations for further research.

Interfacial Edge Crack Between Two Bonded Dissimilar Orthotropic Strips Under Antiplane Point Loading, Xiangfa Wu, Yuris A. Dzenis, Wen-Sheng Zou

Department of Engineering Mechanics: Faculty Publications

A closed-form solution is obtained for the interfacial edge crack between two bonded dissimilar orthotropic strips loaded by antiplane point loading in form of screw dislocation or line force. Conformal mapping and existing dislocation solutions are utilized for constructing the fundamental solution of the problem. The stress intensity factor (SIF) and the energy release rate(ERR) are obtained explicitly.

Determination Of Properties Of Composite Materials From The Lamb Wave Propagation: Probabilistic, Interval, And Fuzzy Approaches, Fariba Ansari, William Durrer, Soheil Nazarian, Vladik Kreinovich

Departmental Technical Reports (CS)

One of the most efficient non-destructive techniques for finding hidden faults in a plate is the use of ultrasonic Lamb waves. These waves are reflected by faults, and from this reflection, we can locate the faults. For that, we need to know how the Lamb waves propagate. Their propagation is determined by the dynamic elastic constants C_pq, so we must find these constants. These constants cannot be measured directly; instead, we measure the dependence of the speed of frequency c(f), and we must reconstruct C_pq from the measured values of c(f). In this paper, we show how this can be …

Experimental Investigation Of Dynamic Response Of Compacted Clayey Soils, Gokhan Inci, Nazli Yesiller, Takaaki Kagawa

Civil and Environmental Engineering

A study was conducted to determine the dynamic properties of compacted clayey soils subjected to low amplitude vibration. A fast and simple ultrasonic pulse transmission method was used. Tests were conducted on three clayey soils with low to high plasticity compacted using standard and modified Proctor effort over a range of water contents. The samples were allowed to dry after compaction and P-wave velocity, S-wave velocity, Poisson's ratio, and shear modulus were determined. The effects of soil type, compaction conditions, and degree of saturation on the dynamic response of the soils were investigated. The elastic wave velocities and the dynamic …

Qualitative And Statistical Analysis Of The Florida Photovoltaic Rebate Program, Florida Solar Energy Center, Jennifer Szaro

FSEC Energy Research Center®

The Florida Photovoltaic (PV) Rebate Program, which began in March of 1999, has led to the installation of 52 utility interactive PV systems in seven electric utility service territories. The Program offered $4 per installed DC Watt to Florida electric consumers who installed grid-connected photovoltaic equipment in accordance with a series of quality control requirements developed and administered by the Florida Solar Energy Center. All rebated installations are currently being monitored in an effort to collect statistically significant reliability, performance and cost data on grid-connected PV systems. Funding for this program was provided through a one-time grant from the Florida …

Inside Unlv, Kevin Force, Gian Galassi, Carol C. Harter, Stuart Mann

Inside UNLV

No abstract provided.

The Localized Corrosion Behavior Of 6% Mo And 316l Stainless Steels In Chloride Media And The Effect Of Applied Mechanical Stress, Houssam El-Din Sabry Ahmed

Archived Theses and Dissertations

Electrochemical techniques were applied to study the crevice corrosion resistance of two types of stainless steel alloys namely, conventional 316L and super austenitic 6% Mo in acidified 3% NaCl solution at room temperature. Potentiodynamic results showed that 6% Mo alloy possessed a remarkable resistance to crevice corrosion compared to 316L alloy when tested in the same solution. The breakdown potential at which passivity broke down for 316L alloy was 0.00 m V, SCE, the corresponding value for 6% Mo alloy could not be reached up to the potential value of 700 m V, SCE. 316L alloy suffered extremely from crevice …

Scattering Of Elastic Waves In Damaged Media, Liyong Yang, Joseph A. Turner

Nebraska Center for Materials and Nanoscience: Faculty Publications

The scattering of elastic waves in a medium with damage from microcracking is discussed. The influence of damage from penny-shaped microcracks within a homogeneous medium is considered. The microcracks are assumed to be randomly oriented and uniformly distributed. Explicit expressions are derived for the attenuation of longitudinal and shear elastic waves in terms of the damage parameter and the effective elastic moduli of the medium. A generalized tensor-based approach is used such that the results are coordinate free. The derivation is based upon diagrammatic methods. The problem is formulated in terms of the Dyson equation, which is solved for the …

Bs News

Building Services Engineering

No abstract provided.

Intelligent Transportation Systems Statewide Architecture, Joseph D. Crabtree, Jennifer R. Walton

Kentucky Transportation Center Research Report

This report describes the development of Kentucky’s Statewide Intelligent Transportation Systems (ITS) Architecture. The process began with the development of an ITS Strategic Plan in 1997-2000. A Business Plan, developed in 2000-2001, translated the goals of the Strategic Plan into specific project recommendations. To develop the Statewide Architecture, the project team first inventoried all existing and planned ITS projects in the state. A project architecture was developed for each identified project, and these project architectures were then merged to form the Statewide Architecture. This report describes the background work that set the stage for the architecture, the actual architecture development …

Understanding Market Stakeholder Perspectives: Application In The Biopharmaceutical Industry, Halvard Nystrom, Kalayanee Poon-Asawasombat

Engineering Management and Systems Engineering Faculty Research & Creative Works

New products are sometimes perceived as risky. This article contributes a process that new product development teams can use to better understand stakeholders' concerns. the stakeholder analysis process is appropriate for products that can be perceived as risky since it enables developers to address key issues of concern prior to new product introduction, mitigating market acceptance risk. It uses a stakeholder model that facilitates dialogue to understand market risks and guide the assessment process. This article includes a case study describing a successful application of introducing biopharmaceutical products, as well as some of the key findings to demonstrate usefulness. © …

The Effectiveness Of Sacp In Controlling Of Concrete Steel Reinforcement In Aggressive Environments, Hassan Ali Abubaker Al Jafri

Theses

The Arabian Gulf is considered to be one of the world's most aggressive environments for reinforced concrete. Traditional methods of corrosion protection may not be enough to provide the required level of corrosion control for the design life of concrete structures in such environments.

Cathodic protection has been found as a viable technique of inhibiting chloride induced corrosion of steel in concrete structures. As an alternative to impressed current cathodic protection ICCP a remarkable developments recently have been made in the application of sacrificial anode cathodic protection as a means of enhancing the performance of patch repair.

The main objective …

Investigation Of An Integrated Regional Environmental Watershed Methodology, Marshall R. Boggio

Dissertations

Recent public awareness of the environment has placed increased emphasis on the health and current state of the regional watershed. The watershed has been defined as that area in which water flowing across and beneath a given land surface drains into a specific stream or river, ultimately flowing through a single point or outlet on that stream or river. Since the processes involved are many and are analyzed in the literature on an individual basis, the current investigation attempts a more holistic approach by suggesting a methodology that integrates all elements of the hydrologic cycle. The investigation utilizes the area …

Direct Simulation Of Electrorheological Suspensions Subjected To Pressure Driven Flow And Spatially Non-Uniform Electric Field, Arun Thankamony John Kadaksham

Theses

A numerical method based on the distributed Lagrange Multiplier method is developed for direct simulation of electrorheological (ER) suspensions subjected to pressure driven flows and spatially non-uniform electric fields. The flow inside particle boundaries is constrained to be rigid body motion by the distributed Lagrange multiplier method and the point-dipole approximation is used to model the electrostatic forces acting on the polarized particles. Simulations show that the particles move to the regions of high electric field when the value of β, the Clausius-Mossotti factor is positive and they move to the regions of low electric field when the value of …

Intrusion Detection System For Ad Hoc Mobile Networks Using Neighborhood Watch Theory, Ramani Rajagopalan

Theses

This study describes several experiments to simulate and study temperature sensor networks. The ultimate goal of this study is to accurately predict a temperature sensor failure in a sensor network, using Network Neighborhood Watch theory. Simulated temperature measurements are used to compare the results of accuracy, and quickness in detecting a failure in a malfunctioning sensor node. This is done by changing the intervals between temperature sampling, by considering different rates of temperature raise, as well as varying the number of nodes in the network neighborhood (deployment density). The thesis studies the threshold for temperature sensor failure by computing a …

Sub-Segment Based Transport Layer Protocol For Wireless Medium, Som Sengupta

Theses

This thesis discusses the techniques to improve the TCP over wireless. The loss-intensive wireless communication results in high retransmission rates to recover lost packets and bandwidth consumption. In addition, the retransmitted segments have significant chance of being dropped. To make the retransmission process more granular, large segments at the transport layer (540 bytes, by default) can be subdivided into smaller sub-segments. This document introduces a split TCP based solution and describes how to produce a series of smaller-sized segments that share the same transport layer header. A new header format is introduced to support the transmission of smaller segments …

High Resolution Wind Retrieval For Seawinds On Quikscat, Jeremy Blaine Luke

Theses and Dissertations

An algorithm has been developed that enables improved the resolution wind estimates from SeaWinds data. This thesis presents the development of three key portions of the high resolution wind retrieval algorithm: Compositing individual σ-0 measurements and Kp, Retrieved wind bias correction, and ambiguity selection for high resolution winds. The high resolution winds produced by this algorithm are expected to become a useful resource for scientists and engineers studying the ocean winds. The high resolution wind retrieval algorithm allows wind to be retrieved much closer to land than is available from the low resolution winds estimated from the same scatterometer by …

Polar Sea Ice Mapping For Seawinds, Hyrum Spencer Anderson

Theses and Dissertations

In recent years, the scientific community has expressed interest in the ability to observe global climate indicators such as polar sea ice. Advances in microwave remote sensing technology have allowed a large-scale and detailed study of sea ice characteristics. This thesis provides the analysis and development of sea ice mapping algorithms for the SeaWinds scatterometer. First, an in-depth analysis of the Remund Long (RL) algorithm for SeaWinds is performed. From this study, several improvements are made to the RL algorithm which enhance its performance. In addition, a new method for automated polar sea ice mapping is developed for the SeaWinds …

Initial Stages Of Pd Deposition Onto Au(111) Electrodes From Pdso4, Jing Tang, Petri M., Kibler L.A., Kolb D.M.

Journal of Electrochemistry

Metal thin films have attracted considerable interest in relation to catalysis, energy, material, corrosion and environmental protection. Pd thin film is capable of proton reduction and strong hydrogen absorption, which has shown electrocatalytic activity to the oxidation of small organic molecules. In this paper, in-situ STM measurements are performed to study the deposition process and the influence of the surface structure and anion adsorption. When Pd is deposited from PdSO₄ solution on Au(111) in the UPD range, a monolayer of Pd with pseudomorphic (1×1) structure was formed on the substrate with induced (3×7) R19° SO₄^2- adsorption. With …