Engineering Commons^™

Asphaltene As Light Harvesting Material In Dye Sensitized Solar Cell, Rajab Emhemed Abujnah

Open Access Theses & Dissertations

This Dissertation characterizes the first asphaltene DSSC (dye-sensitized solar cell), in which light to electricity conversion efficiency has improved from 0 % to 1.8 %. Four natural organic asphaltene factions, namely, un-fractionated asphaltene, Fr. 1 Asphaltene, Fr.2 asphaltene, Fr.3 and Fr.4 were extracted and tested for various solar cell parameters of TiO2 based dye-sensitized solar cell DSSC. DSSCs were fabricated using the four individual asphaltene dyes. The photovoltaic performance of the cells was examined by determining the various parameters such as open-circuit voltage, short-circuit current, fill factor, and series resistance. The overall energy conversion efficiency was also measured to correlate …

Adaptation Of Low Impact Design To The Desert Southwest, Abubaker Ali Alamailes

Open Access Theses & Dissertations

A low Impact Development (LID) practices were used to design an Integrated Management Practices (IMP) system for a residential lot .The design was adapted to the Desert Southwest region based on twenty years of climate data including precipitation and temperature for three representative cities: El Paso, TX, Albuquerque, NM, and Phoenix, AZ. In order to capture stormwater runoff close to its source and to provide as much stored water as possible for plants, LID practices including bioretention cells and vegetated swales were applied throughout the lawn. The purpose of the design is to maintain the pre-development hydrologic characteristics of the …

Software And Hardware Techniques To Aid In Automating And Troubleshooting Hybrid Systems That Fabricate Three-Dimensional Electronics, Mohammed Alawneh

Open Access Theses & Dissertations

Various issues in automating the fabrication of three dimensional electronics were addressed in this thesis. The three dimensional electronics were fabricated by a stereolithoraphy and direct print hybrid system. Hardware and software limitations were discussed and possible solutions were implemented. Various automation software tools were developed, specifically a computer aided design to printed electronics conversion software compatible with various stages.

Automated Detection Of Dust Clouds, Sources, And Direction From Noaa-Avhrr Satellite Imagery, Mohammed Qassim Alkhatib

Open Access Theses & Dissertations

This research is mainly focused on automatically locating dust sources and estimating their transport direction in NOAA-AVHRR images. Applications of AVHRR images may include agricultural assessment, producing maps of large area, and to retrieve various geophysical parameters. The AVHRR simultaneously records five bands of data, in our research, we focused on bands four and five since these wavelengths highlight the absorption and subsequent emission of thermal radiation by the silicate particles in the dust storms.

In this research, we propose a new method to detect dust clouds on satellite images. The approach we propose involves the use of an image …

Combustion Of Lunar Regolith Mixed With Energetic Additives: Thermodynamic Calculations And Experimental Studies, Francisco Alvarez

Open Access Theses & Dissertations

The future of space exploration will require longer missions in order to better understand the conditions of near-Earth celestial objects, like the Moon or Mars. Future space missions will require the development of goods, such as propulsion fuel and structural materials, produced using the extraterrestrial resources available. The area that develops these technologies is called In-Situ Resource Utilization (ISRU). ISRU allows reducing the payload, and as a consequence reduces the energy consumption and cost of space travel. The production of structural materials on the Moon can be accomplished using Self-Propagating High-Temperature Synthesis (SHS). This work describes the combination of ISRU …

Effects Of The Usage Of Parallel Hardware Architectures In The Simulation Of Artificial Neural Networks Training Process, Carlos Beas

Open Access Theses & Dissertations

Long training times and non-ideal performance have been a big impediment in further continuing the use of Artificial Neural Networks for real world applications. Current research is currently focused on two areas of study that aim to address this problem. The first approach seeks to overcome large training times by devising faster learning algorithms where a set of interconnection weights for which the network produces negligible error takes a less amount of computation to find [Sun98]. The second approach aims to address the impediment by implementing existing training algorithms but on parallel hardware architectures.

While both approaches provide promising advances …

Design And Cfd Optimization Of Methane Regenerative Cooled Rocket Nozzles, Christopher Linn Bradford

Open Access Theses & Dissertations

Liquid rocket engines benefit in life cycle from the active regenerative cooling method which passes the fuel as the coolant through channels surrounding the combustion chamber. These channels are designed and optimized using structural considerations as well as heat transfer theory, then CFD simulations with the software FLUENT are performed for the final analysis. The difficulty in using methane as the fuel/coolant is addressed, and requires the use of the ideal gas numerical model in preliminary CFD simulations. Comparison to real gas numerical models is made, and results also given for one channel design. The techniques utilized herein allow the …

2d Gaussian Object Motion Detection, Miguel Angel Chaidez

Open Access Theses & Dissertations

Dr. John Moya, and associated research assistants, have previously created an image-change recognition algorithm (JESSE) to mark changes within an image. The focus of this thesis is to present a physical application and modification of this algorithm in order to detect a surgeon's hand and verify chip placement on a printed circuit board.

There are different techniques in implementing visual recognition and motion detection with smart systems but the high cost and complicated calibration of these systems make them impractical. The goal was to create a system that is simple, inexpensive and applicable to multiple applications that will allow the …

Experimental And Numerical Investigation Of The Effect Of Fuel Composition On Flame Stability On A Gas Turbine Combustor, Gilberto Corona

Open Access Theses & Dissertations

Gas turbines are used for power generation and aviation all over the world. Fossil fuels remain the main source of energy for the operation of gas turbines but the recent increase in environmental awareness has influenced government agencies to impose stringent limits on pollutant emissions from power generation plants. Pollutant emissions control is one of the major challenges for gas turbine designers. In this study, experimental methods and computational fluid dynamics (CFD) technologies are used to study the problems that arise when coal derived fuels are used in Gas Turbine Combustors.

Gas turbine designers need both experimental data and combustion …

Improved Joining Method For Segmental Prestressed Structures, Ralph Warren Jensen

Open Access Theses & Dissertations

This dissertation addresses the need for more robust and materially efficient structures, specifically structures that absorb higher levels of energy, can self-erect and which have variable reaction capabilities. These structures can take much higher levels of strain and loading compared to current technologies in reinforced concrete and carbon fiber composites. These structures are made using a novel method of joining segmental elements. A great advantage with this segmental structural system is it's survivability under overloaded conditions. During an impact, or concentrated pressure load, the structure will wrap around the impact zone thereby widely distributing the contact stresses. This function or …

Development Of A Gis Fiber Optics Assetmanagement System For The City Of El Paso, Luis Fernando Quintana

Open Access Theses & Dissertations

The GIS Fiber Optics Asset Management System (GFOAMS) was developed for the City of El Paso, to manage the public fiber optics infrastructure. Using a map-driven interface, the GFOAMS is composed of three modules: inventory, documents, and images. Its interactive multilayer data structure contains information for Junction Boxes, Conduit Runs, and Cables for twelve fiber optic systems across the city. The fiber optics network stored in the GFOAMS connects city buildings and facilities such as police departments, fire departments, municipal courts, health administration building, public transportation facilities/Sun Metro, libraries and others. Applications of the GFOAMS include tools to easy access …

Development And Characterization Of The Oxidation Behavior Of Various High Temperature Niobium Based Alloys, Benedict Isabel Portillo

Open Access Theses & Dissertations

The oxidation response of various niobium based refractory alloys from the Nb-Mo-Si-B-X alloy system has been examined at temperatures between 700 and 1400°C in air. The development of these alloys was part of an ongoing effort to develop and discover a new materials system capable of replacing nickel based super alloys. Additions of titanium were found to provide limited oxidation resistance. A discontinuous layer of TiO2 was observed to from at temperatures above 1100°C. Alloys containing titanium additions were observed to suffer from pest oxidation at low and intermediate temperatures due to the development of Nb2O5. Poor oxidation resistance at …

Development Of Load Balancing Algorithm Based On Analysis Of Multi-Core Architecture On Beowulf Cluster, Damian Valles

Open Access Theses & Dissertations

In this work, analysis, and modeling were employed to improve the Linux Scheduler for HPC use. The performance throughput of a single compute-node of the 23 node Beowulf cluster, Virgo 2.0, was analyzed to find bottlenecks and limitations that affected performance in the processing hardware where each compute-node consisted of two quad-core processors with eight gigabytes of memory. The analysis was performed using the High Performance Linpack (HPL) benchmark.

In addition, the processing hardware of the compute-node was modeled using an Instruction per Cycle (IPC) metric that was estimated using linear regression. Modeling data was obtained by using the Tuning …

Utepcam: A Scalable Wireless Vision Sensor Architecture For Computational, Power And Bandwidth Constrained Scenarios, Ricardo Zepeda

Open Access Theses & Dissertations

UTEPcam is a low cost and power vision sensor node system. UTEPcam is composed of an Atmel atmega32 8-bit microcontroller, a CY7C09099V static RAM chip, an OV6620 CMOS image sensor, a XBEE transceiver and a SD Flash memory card, and four logic gates. UTEPcam's simple yet efficiently architecture enables it to capture video at one frame per second. At its absolute highest, it is estimated that UTEPcam consumes only 1.321 Amps. When in standby, UTEPcam consumes 21 microamps. Furthermore, UTEPcam's program takes up only 1Kbyte of memory space.

UTEPcam's CPU, a simple 8-bit MCU, is unlike most vision sensor node …

An Ultra Low Power Subthreshold Delta Sigma Digital To Analog Converter, Ricardo Baca

Open Access Theses & Dissertations

Abstract

In the last four decades the incorporation of analog, digital and mixed-signal integrated circuits (IC) using Complementary Metal Oxide Semiconductor (CMOS) technology has been dramatically increasing and is improving almost every aspect of modern life. Furthermore, the continuous advances in CMOS Very Large System Integration (VLSI) technology allow higher integration densities and the increasing number of subsystems in a single chip results in higher speed execution and lower power consumption. Therefore, the increasing digitalization in electronic circuits across a wide range of battery-operated applications where reliability and power dissipation are critical requires Digital to Analog Converters (DACs) with higher …

Analysis Of Endocrine Disrupting Compounds In Wastewater Treatment Plants: A Perspective Of Trans-Boundary Waterborne Pollution, Roberto De La Torre

Open Access Theses & Dissertations

Recent decades have brought an increasing concern of potential adverse human and ecological health effects resulting from Endocrine Disruptor Compounds (EDCs). In particular from new emerging compounds such as natural estrogens (e.g., 17©¬-estradiol, estrone), synthetic estrogens (e.g., 17Â¥á-ethynylestradiol), bisphenol A (BPA), nonylphenol ethoxylates (NPEOS), and nonylphenol (NP). These chemicals which are also known as organic wastewater contaminants are released directly to the environment after passing through wastewater treatment plants (WWTPs), which often are not designed to remove them from the effluent. The occurrence of the aforementioned compounds in surface water is becoming of increasing concern worldwide, and has led to …

Tin Dioxide Memristors On Glass And Plastic Substrates, Oscar Del Real

Open Access Theses & Dissertations

NanoMIL has studied and developed SnO2-based memristors, while the W.M Keck Center has been a research leader in printed silver inks. The focus of this thesis is to take the previous generation of memristors on glass and develop a process for creating memristors on flexible Kapton film for the first time. Moreover, collaborative work between the two UTEP laboratories produced memristors with printed silver top electrode contacts, also for the first time. These approaches may enable inexpensive flexible memory.

Maturation of the process was achieved by understanding important process parameters and subtle differences between glass and Kapton substrates. Moreover, electrical …

Development Of A New Mix Design Method And Specification Requirements For Asphalt Treated Bases, Hector Antonio Hernandez

Open Access Theses & Dissertations

Asphalt stabilized bases in Texas are usually designed and constructed as per Item 292, "Asphalt Treatment (Plant Mixed)," of the 2004 Standard Specification book. This specification is a hybrid of base and hot mix asphalt concrete procedures and requirements, which are sometimes incompatible. In addition, this Item uses a specific Texas Gyratory compactor that is not readily available to all districts. Some districts have started using test method Tex-204-F, Part III, `Mix Design for Large Stone Mixtures Using the Superpave Gyratory Compactor." However, this procedure was originally developed to design Type A and Type B hot mix at 96% density …

Estimating Mean Under Interval Uncertainty And Variance Constraint, Ali Jalal-Kamali, Luc Longpre, Misha Kosheleva

Departmental Technical Reports (CS)

Universal Approximation With Uninorm-Based Fuzzy Neural Networks, Andre Lemos, Vladik Kreinovich, Walmir Caminhas, Fernando Gomide

Departmental Technical Reports (CS)

Fuzzy neural networks are hybrid models capable to approximate functions with high precision and to generate transparent models, enabling the extraction of valuable information from the resulting topology. In this paper we will show that the recently proposed fuzzy neural network based on weighted uninorms aggregations uniformly approximates any real functions on any compact set. We will describe the network topology and inference mechanism and show that the universal approximation property of this network is valid for a given choice of operators.

Testing Shock Absorbers: Towards A Faster Parallelizable Algorithm, Christian Servin

Departmental Technical Reports (CS)

Cars are equipped with shock absorbers, which are designed to smooth out the shocks on the road. In practice, there is a need to test them. To test the shock absorbers, we need to estimate the values of the shock absorber's parameters. If we did not have any measurement errors, then two measurements would be sufficient to determine the parameters. However, in reality, there are measurement errors. Usually, in engineering practice, it is assumed that the errors are normally distributed with 0 mean, so we can use least squares method to test it. In practice, we often only know the …

Fundamental Physical Equations Can Be Derived By Applying Fuzzy Methodology To Informal Physical Ideas, Eric Gutierrez, Vladik Kreinovich

Departmental Technical Reports (CS)

Fuzzy methodology transforms expert ideas -- formulated in terms of words from natural language -- into precise rules and formulas. In this paper, we show that by applying this methodology to intuitive physical ideas, we can get fundamental physical equations. This fact provides an additional justification for the fuzzy methodology.

From Single To Double Use Expressions, With Applications To Parametric Interval Linear Systems: On Computational Complexity Of Fuzzy And Interval Computations, Joseph A Lorkowski

Departmental Technical Reports (CS)

In many practical problems, we need to estimate the range of a given expression f(x1, ..., xn) when each input xi belongs to a known interval [xi] -- or when each input xi is described by a known fuzzy set. It is known that this problem is easy to solve when we have a Single Use Expression, i.e., an expression in which each variable xi occurs only once. In this paper, we show that for similarly defined Double Use Expressions, the corresponding range estimation problem is NP-hard. Similar problems are analyzed for the problem of solving linear systems under interval …

Reducing Over-Conservative Expert Failure Rate Estimates In The Presence Of Limited Data: A New Probabilistic/Fuzzy Approach, Carlos M. Ferregut, F. Joshua Campos, Vladik Kreinovich

Departmental Technical Reports (CS)

Unique highly reliable components are typical for aerospace industry. For such components, due to their high reliability and uniqueness, we do not have enough empirical data to make statistically reliable estimates about their failure rate. To overcome this limitation, the empirical data is usually supplemented with expert estimates for the failure rate. The problem is that experts tend to be -- especially in aerospace industry -- over-cautious, over-conservative; their estimates for the failure rate are usually much higher than the actual observed failure rate. In this paper, we provide a new fuzzy-related statistically justified approach for reducing this over-estimation.

Least Sensitive (Most Robust) Fuzzy "Exclusive Or" Operations, Jesus E. Hernandez, Jaime Nava

Departmental Technical Reports (CS)

In natural language, "or" sometimes means "inclusive or" and sometimes means "exclusive or". To adequately describe commonsense and expert knowledge, it is therefore important to have not only t-conorms describing fuzzy "inclusive or" operations, but also fuzzy "exclusive or" operations f(a,b). Since the degrees of certainty are only approximately defined, it is reasonable to require that the corresponding operation be the least sensitive to small changes in the inputs. In this paper, we show that the least sensitive fuzzy "exclusive or" operation has the form f(a,b)=min(max(a,b),max(1-a,1-b)).

Adding Constraints -- A (Seemingly Counterintuitive But) Useful Heuristic In Solving Difficult Problems, Olga Kosheleva, Martine Ceberio, Vladik Kreinovich

Departmental Technical Reports (CS)

Intuitively, the more constraints we impose on a problem, the more difficult it is to solve it. However, in practice, difficult-to-solve problems sometimes get solved when we impose additional constraints and thus, make the problems seemingly more complex. In this methodological paper, we explain this seemingly counter-intuitive phenomenon, and we show that, dues to this explanation, additional constraints can serve as a useful heuristic in solving difficult problems.

Mamdani Approach To Fuzzy Control, Logical Approach, What Else?, Samuel Bravo, Jaime Nava

Departmental Technical Reports (CS)

In fuzzy control, two approaches are mainly used: Mamdani's approach, in which we represent the knowledge base as a disjunction of statements Ai(x) & Bi(u) corresponding to individual rules, and logical approach, in which the knowledge base is represented as a conjunction of the rules themselves Ai(x) --> Bi(u). Both approaches are known not to be perfect, so a natural question arises: what other approaches are possible? In this paper, we describe all possible approaches; alternative approaches use an "exclusive or" operation and correspond, e.g., to the fuzzy transform idea.

From Program Synthesis To Optimal Program Synthesis, Joaquin Reyna

Departmental Technical Reports (CS)

Fusing Continuous And Discrete Data, On The Example Of Merging Seismic And Gravity Models In Geophysics, Omar Ochoa, Aaron Velasco, Vladik Kreinovich

Departmental Technical Reports (CS)

Towards Optimal Placement Of Bio-Weapon Detectors, Chris Kiekintveld, Octavio Lerma

Departmental Technical Reports (CS)

Biological weapons are difficult and expensive to detect. Within a limited budget, we can afford a limited number of bio-weapon detector stations. It is therefore important to find the optimal locations for such stations. A natural idea is to place more detectors in the areas with more population -- and fewer in desert areas, with fewer people. However, such a commonsense analysis does not tell us how many detectors to place where. To decide on the exact placement of bio-weapon detectors, we formulate the placement problem in precise terms, and come up with an (almost) explicit solution to the resulting …