Engineering Commons^™

High-Order Central Finite-Volume Schemes For Atmospheric Modeling, Kiran Kumar Katta

Open Access Theses & Dissertations

Atmospheric numerical modeling has been going through drastic changes over the past decade, mainly to utilize the massive computing capability of the petascale systems. This obliges the modelers to develop grid systems and numerical algorithms that facilitate exceptional level of scalability on these systems. The numerical algorithms that can address these challenges should have the local properties such as the high on-processor operation count and minimum parallel communication i.e., high parallel efficiency. They should also satisfy the following properties such as inherent local and global conservation, high-order accuracy, geometric flexibility, non-oscillatory advection and positivity preservation properties. The goal of this …

Analysis Of Isolated Traffic Signal Control Systems, Petr Malina

Open Access Theses & Dissertations

Intelligent Transportation Systems (ITS) are implemented for increase of efficiency and safety in transportation. This thesis focuses on the area of traffic signal timing operations which is one of ITS components. The first objective is to compare the Czech and the U.S. methods for isolated fixed time traffic signal control, using an intersection in El Paso, Texas, as the test site. The second objective of this thesis is to evaluate the U.S. actuated isolated timing plan and compare it against the Czech and U.S. fixed time controls. A microscopic traffic simulation model of the selected intersection is coded in VISSIM …

Video Mosaicing Using Inertial Sensors, Arturo Maya Pereyra

Open Access Theses & Dissertations

A method to reduce the process complexity of Video Mosaicing could rely on information concerning the orientation of the camera instead of image feature tracking. Inertial sensors (e.g. accelerometers and gyros) could form part of a low cost motion based technology which can be used in this case and this thesis details an approach for Video Mosaicing based on such technology that requires non-computationally intensive algorithms.

Water Mass Balances For The Rio Grande/Bravo From Fort Quitman, Texas To Foster Ranch Near Langtry, Texas: An Assessment Of Factors, Ramiro Lujan

Open Access Theses & Dissertations

ABSTRACT

Water availability is declining in many regions of the planet, particularly in arid and semi-arid regions. Water bodies located in these regions, like the Rio Grande/Bravo at the U.S. - Mexico border, are subjected to high water demands. This research project makes an assessment of the spatial and temporal variability of elements intervening in the water mass balance for the section of the Rio Grande/Bravo between Fort Quitman and Langtry, Texas during the time period extending from January 1990 through December 2005. This document mentions the main Rio Grande/Bravo stakeholders from the U.S. and Mexico, and describes issues related …

Multi-Objective System Design Optimization Considering Environmental Emissions, Olivia Carolina Moreno

Open Access Theses & Dissertations

The well-known reliability optimization problem, the redundancy allocation problem (RAP) involves the simultaneous selection of system components and a design level configuration that can meet several design constraints in order to optimize the predefined objective function(s). The RAP has been predominantly solved as a single objective optimization problem with the reliability of the system to be maximized or system design cost to be minimized. When considered as a multiple objective reliability optimization problem, the system reliability is maximized and the cost and weight of the system are minimized. In this work, the RAP was formulated as a multiple objective optimization …

Evaluation Of A Cash Award Program For Water Conservation, Robert Moss

Open Access Theses & Dissertations

This document is the final report of a water conservation study funded by the U.S. Bureau of Reclamation and The University of Texas at El Paso with cooperation from El Paso Water Utilities. The study period was from September, 1997 through January, 2000.

Development Of A High Pressure Optically Accessible Combustor And Shear Co Axial Injector, Christopher David Navarro

Open Access Theses & Dissertations

A trend in the last decade in the field of propulsion and rocketry is leaning toward the use of the combination of Liquid Methane and Liquid Oxygen as propellant fuels. This is in contrast with the earlier trend of using Hydrogen systems and toxic hypergolic systems. The Multi-Purpose Optically Accessible Combustor (MOAC) and Shear Coaxial injectors have been developed to investigate injector design and combustion research involving Oxygen and Methane propellants. The MOAC is intended for the experimentation and research of combustion of liquid and gaseous propellants. Development of the MOAC system and versatility to use a number of injector …

Development Of Models To Estimate Modulus And Permanent Deformation Of Texas Bases, Eric Navarro

Open Access Theses & Dissertations

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Use Of Environmental Isotope Tracer And Gis Techniques To Estimate Basin Recharge, Abdulganiu A.A. Odunmbaku

Open Access Theses & Dissertations

The extensive use of ground water only began with the advances in pumping technology at the early portion of 20th Century. Groundwater provides the majority of fresh water supply for municipal, agricultural and industrial uses, primarily because of little to no treatment it requires. Estimating the volume of groundwater available in a basin is a daunting task, and no accurate measurements can be made. Usually water budgets and simulation models are primarily used to estimate the volume of water in a basin.

Precipitation, land surface cover and subsurface geology are factors that affect recharge; these factors affect percolation which invariably …

Nanoprobe I-V Characterization Of Cdte/Cds Micro And Nano-Patterned Solar Cells, Heber Prieto

Open Access Theses & Dissertations

This thesis presents a novel way to characterize micro and nano patterned cadmium telluride thin film solar cells via a nano-probe system. A historical review of CdTe-based solar cells is presented first followed by review of the technology developed to produce the patterned CdTe cells. A detailed presentation is then provided on the use of a Zyvex nanoprobing system to characterize the patterned solar cells. The I-V response of micro- and nano-patterned solar cells stimulated under different e-beam conditions is presented and analyzed. Suggestions of how to improve the technique are provided. This work documents, for the first time, the …

The Influence Of Build Parameters On The Microstructure During Electron Beam Melting Of Ti6al4v, Karina Puebla

Open Access Theses & Dissertations

With the demand of devices to replace or improve areas, such as: electronic, biomedical and aerospace industries. Improvements in these areas of engineering have been in need due to the customer’s needs for product properties requirements. The design of components must exhibit better material properties (mechanical or biocompatible) close to those of any given product. Rapid prototyping (RP) technologies that were originally designed to build prototypes may now be required to build functional end-use products. To carry out the transition, from RP to rapid manufacturing (RM), the available materials utilized in RP must provide the performance required for RM. The …

Position Sensitive Device With Gaussian Response, Sinohe Rodriguez

Open Access Theses & Dissertations

Much work has been done in improving the linearization of position sensitive devices, PSDs. However, a novel way of position detection using Gaussian filters has recently been developed. An obvious extension of this approach is possible via the electro-optical implementation of the Gaussian filters. This thesis proposes a PSD that has such a Gaussian output response to an incident light spot moving across its surface. The proposed device is based on a simple and inexpensive p-n junction. The device is simulated using finite-difference frequency-domain numerical analysis within Matlab.

Low Energy Disruption Of Lipid Containing Biomass, Joaquin Rodriguez

Open Access Theses & Dissertations

Lipid containing biomass from microalgae has received recent research interest as a renewable and sustainable feedstock for biofuel production. Algae is known to offer as much as 30 times the energy density than corn based ethanol, the current world standard for biomass based liquid transportation fuels. The development of large scale systems and methods of extracting lipids from microalgae is still in the early stages of development and significant increases in efficiency and reduction in costs are necessary to substantiate algae as a feasible alternative source of fuel. Traditional conversion of algae feedstock into a refineable feedstock for biofuel can …

Oxidation Of Borides And Carbides With Y2o3 And Ta Additions, Salvador Manuel Rodriguez

Open Access Theses & Dissertations

The study presented here describes an investigation of an oxidation scale of a fully-sintered Y2O3-ZrB2-TiC composite exposed in air at 1173K. Upon oxidation of the boride/carbide, a ZrO2-TiO2 was expected to form similar to the ZrO2-SiO2 dual scale of an oxidized ZrB2-SiC. The 47wt% Y2O3-38wt%ZrB2-16wt%TiC composite formed a dual scale consisting primarily of an Y2O3-ZrO2-TiC inner scale with an outer scale of ZrO2-TiO2-Y2O3.

The samples oxidized with a parabolic layer growth allowing the calculation of the effective diffusion coefficient indicating that the oxidation was controlled by oxygen ingress through primarily the ZrO2-Y2O3 phase. The oxygen potential between the inner layer …

Identification Of Rework Station Location To Enhance Reworkability Using Design For Disassembly, Juan Alejandro Saavedra

Open Access Theses & Dissertations

Rework stations are commonly established as part of each assembly stations causing the material flow of the process to be constantly interrupted. Another option is to place the rework station at the end of the production, but this is not cost effective. This breakeven point between reworkability and cost methodology has been proposed in this thesis to identify the location of a single rework station in an assembly line in order to enhance reworkability using the Design for Disassembly (DfD) principles. The methodology uses the 17 guidelines of DfD in a manufacturing scenario in order to propose a reworkability index …

Determination Of The Dynamic Behavior Of Subjects With Diabetic Neuropathy, Luis G. Sagarnaga Lopez

Open Access Theses & Dissertations

The diabetic foot is one of the most feared complications of diabetes [3]. Causes of a diabetic foot come from many disorders including diabetic neuropathy, peripheral vascular disease, charcot's neuropathy, foot ulceration, and limb amputation [4]. Statistics have revealed that 8.3 percent of population in the U.S. is affected by diabetes in 2010, i.e., 25.8 million people. About 60 percent to 70 percent of people with diabetes have mild to severe forms of nervous system damage [13]. There is an enormous impact on the physical and mental health of patients who suffer from diabetes.

This research was to determine the …

Investigation On A Gas-Solid Fluidized Bed Hydrodynamics Using A Non-Intrusive Technology To Visualize Flow Field, Md Rashedul Hasan Sarker

Open Access Theses & Dissertations

The biggest challenge for 21st century is to fulfill global energy demand and at the same time reduce detrimental impact on environment. Gasification technology can meet the requirement and also reduce emission without compromising its performance. In coal gasification, instead of burning coal completely a partial combustion takes place with presence of steam and limited amount of oxygen. In this controlled environment a chemical reaction takes place and produces a mixture of clean synthetic gas. Gas-solid fluidized bed is one type of gasification technology. During gasification mixing behavior of solid (coal) and gas and their flow pattern very complicated to …

Evaluation Of Non-Nuclear Devices In Measuring Moisture Content And Density Of Soils, Martin Jesus Sotelo

Open Access Theses & Dissertations

The objective of this report was to assess the ability of several different devices to measure moisture content and dry density of various compacted geomaterials. The experimental research involved the testing of different subgrade soils and one base material. More than a dozen specimens, 2 ft in height and 1.5 ft in diameter, were constructed to evaluate the Transtech SDG 200, Purdue TDR, and the Decagon 10 HS moisture content sensor. The Speedy Moisture Tester and DOT600 Roadbed Water Content Meter were also evaluated using individual soil samples. All materials were tested at five different moisture contents, but at their …

Control Of A Robotic Prototype Multi-Axis Synergistic System, Julio A. Torres

Open Access Theses & Dissertations

Balance is an ability that every person has and uses in normal daily life, to walk, run, stand, dance, etc. However, there are people who suffer a kind of balance impairment. The Computerized Dynamic Posturography (CDP) is technique in balance rehabilitation, where the patient is asked to stand on a moving platform that is equipped with sensors that measure how well you maintain your balance. In this thesis, a new CDP mechatronic system, the Multi-Axis Synergistic System (MASS), for balance assessment is being developed.

As a first stage and as the objective of this research work the transferable control algorithm …

Development Of An Electronic Vehicle Miles Travelled Toll Model, Marketa Vavrova

Open Access Theses & Dissertations

This thesis presents the reasons why the fuel tax is no longer a viable source of revenues and suggests new sources of funding. One possibility is to replace the fuel tax with a distance-based toll applied nationwide. Vehicle miles travelled (VMT) fee is compared to the fuel tax, and the relationship between road infrastructure spending and fuel taxation in the United States (U.S.) and the European Union (EU) is explored. Also the European approach to taxation and tolling is described and compared to the situation in Texas.

The development of a statewide distance-based toll model to estimate the feasibility of …

A Study Of International Wastewater Challenges And Policy In The Tijuana River Watershed, Gloria Ann Villaverde

Open Access Theses & Dissertations

Since the 1930s, untreated and undertreated sewage from Tijuana, Baja California, México has been released into the Tijuana River Watershed causing contamination of the water supply, crops, the Tijuana Estuary and California beaches. Passage of the North American Free Trade Agreement (NAFTA) has exacerbated the problem by causing population and industrial growth explosions for which there have been insufficient services to meet the needs of the people. The waters of the Tijuana River flow (from México) north over the International Border, into the Tijuana Estuary, discharge out to the Pacific Ocean and often flow north, up the California Coast; therefore, …

Implementation Of Evolutionary Algorithms On The Power Industry And Aviation Security, Anuar Jesus Aguirre

Open Access Theses & Dissertations

The main objective of the power electric power grid is to supply reliable electricity to all the customers. Customers could be industrial, commercial, household, transportation and others. The power grid is a complex and large, and it formed by the conjunction of the generation, transmission and distribution system. The present research is focused in power distribution system. A new component replacement analysis method to solve component replacement problems for complex electricity distribution systems using Genetic Algorithms is developed. In the present model a Taylor series expansion is used to approximate the associated opportunity cost for each component in the system. …

Microscopic And Spectroscopic Analysis Of Wo3 And Ti-Doped Wo3 Thin Films, Young Taek Yun

Open Access Theses & Dissertations

Tungsten oxide (WO3) has been a subject of high interest for its unique properties, and recently for its importance in different types of industrial applications which ranges from non-emissive displays, optical, microelectronic, catalytic/photocatalytic, humidity, temperature, gas, and biosensor devices. In this study, WO3 and Ti doped thin films were prepared using radio frequency magnetron reactive sputtering at different substrate temperatures ranging from room temperature to 500 ºC in increments of 100 ºC. After forming a hypothesis based on knowledge of established WO3 properties, we attempt in this work to investigate how the doping influences the roughness and the mean grain …

Efficient Approximation For Security Games With Interval Uncertainty, Chris Kiekintveld, Vladik Kreinovich

Departmental Technical Reports (CS)

There are an increasing number of applications of security games. One of the key challenges for this field going forward is to address the problem of model uncertainty and the robustness of the game-theoretic solutions. Most existing methods for dealing with payoff uncertainty are Bayesian methods which are NP-hard and have difficulty scaling to very large problems. In this work we consider an alternative approach based on interval uncertainty. For a variant of security games with interval uncertainty we introduce a polynomial-time approximation algorithm that can compute very accurate solutions within a given error bound.

Assessment Of Functional Impairment In Human Locomotion: A Fuzzy-Motivated Approach, Murad Alaqtash, Thompson Sarkodie-Gyan, Vladik Kreinovich

Departmental Technical Reports (CS)

Many neurological disorders result in disordered motion. The effects of a disorder can be decrease by an appropriate rehabilitation. To make rehabilitation efficient, we need to monitor the patient and check how well he or she improves. In our previous papers, we proposed a fuzzy-based semi-heuristic method of gauging how well a patient improved. Surprisingly, this semi-heuristic method turned out to be more efficient that we expected. In this paper, we provide a justification for this efficiency.

In the future, it is desirable to combine this fuzzy-assessment approach with results by Alavarez-Alvarez, Trivino, and Cordon who use fuzzy techniques …

Constraint Optimization: From Efficient Computation Of What Can Be Achieved To Efficient Computation Of A Way To Achieve The Corresponding Optimum, Ali Jalal-Kamali, Martine Ceberio, Vladik Kreinovich

Departmental Technical Reports (CS)

In many practically useful cases, we know how to efficiently compute the exact range of a function over given intervals (and, possibly, under additional constraints). In other words, we know how to efficiently compute the minimum and maximum of a given function f(x₁, ..., x_n) on any box. From the practical viewpoint, it is important not only to find the value of the corresponding maximum or minimum, but also to know for what values of the parameters x_i this optimum is attained. We prove a general result: that if we can efficiently compute the optimum, …

Why Bernstein Polynomials Are Better: Fuzzy-Inspired Justification, Jaime Nava, Olga Kosheleva, Vladik Kreinovich

Departmental Technical Reports (CS)

It is well known that an arbitrary continuous function on a bounded set -- e.g., on an interval [a,b] -- can be, with any given accuracy, approximated by a polynomial. Usually, polynomials are described as linear combinations of monomials. It turns out that in many computational problems, it is more efficient to represent a polynomial as Bernstein polynomials -- e.g., for functions of one variable, a linear combination of terms (x-a)^k * (b-x)^n-k. In this paper, we provide a simple fuzzy-based explanation of why Bernstein polynomials are often more efficient, and we show how this informal explanation …

Semi-Heuristic Poverty Measures Used By Economists: Justification Motivated By Fuzzy Techniques, Karen Villaverde, Nagwa Albehery, Tonghui Wang, Vladik Kreinovich

Departmental Technical Reports (CS)

To properly gauge the extent of poverty in a country or in a region, economists use semi-heuristic poverty measures such as the Foster-Greer-Thorbecke (FGT) metric. These measures are used because it was empirically shown that they capture the commonsense meaning of the extent of poverty better than previously proposed measures. However, the fact that these measures are better then a few earlier proposed ones does not necessarily mean that these measures are the best possible; so, it is desirable to look for optimal poverty measures. In this paper, we first use fuzzy techniques to provide a commonsense interpretation of FGT …

In The Beginning Was The Word, And The Word Was Fuzzy, Vladik Kreinovich

Departmental Technical Reports (CS)

No abstract provided.

Estimating Correlation Under Interval Uncertainty, Ali Jalal-Kamali, Vladik Kreinovich

Departmental Technical Reports (CS)

In many engineering situations, we are interested in finding the correlation ρ between different quantities x and y based on the values x_i and y_i of these quantities measured in different situations i. Measurements are never absolutely accurate; it is therefore necessary to take this inaccuracy into account when estimating the correlation ρ. Sometimes, we know the probabilities of different values of measurement errors, but in many cases, we only know the upper bounds Δ_xi and Δ_yi on the corresponding measurement errors. In such situations, after we get the measurement results X_i and Y_{i …}