Engineering Commons^™

Microstructural Characterization And Heat Treatment Of A-286 Turbine Buckets, Christopher Michael Bradley

Open Access Theses & Dissertations

A-286 is an iron-based superalloy used extensively in land-based gas turbines for 2nd stage (low pressure) buckets and 1st and 2nd stage wheels. Although A-286 may appear to some as just another austenitic stainless steel, its elevated temperature properties are attributed to ' precipitate structures, effective distributions of alloy carbides in the forms of M23C6, M6C and MC, and solid solution strengthening. Unfortunately over the course of these components service lives microstructural degradation develops in the form of η-phase formation. The presence of η-phase, especially in large quantities, can have a negative effect on stress rupture properties. Resistance to creep …

Autonomous Vehicle Navigation: A Comparative Study Of Classical Logic And Neural Network Technique, Javier Alejandro Flores

Open Access Theses & Dissertations

Today is an era in which humans need the help of automated machines to facilitate their hectic lives. Over the past few decades, robotics has been one of the most researched areas in the world. One area of this research is obstacle avoidance for autonomous vehicles. In order to avoid an obstacle, the system may include two important characteristics: obstacle detection and avoidance control. In this Thesis a classical logic system and artificial neural network approach is presented. With the help of an Integrated Development Environment, a virtual robot was able to negotiate a maze and avoid obstacles according to …

Novel Approach To Predict The Crash Testing Data Using Multiple Regression Analysis And Principal Component Analysis, Ravi Lochan Kallur

Open Access Theses & Dissertations

In the design process of vehicles, crash tests are very critical to determine the safety measures. Every motor manufacturing company has to maintain certain standards for their autos. This will lead to the design optimization of safety measures utilizing the data available from crash tests. The engineers perform various experiments to generate data from crash testing of vehicles in their manufacturing facility. With the help of simulators; they create a virtual environment to perform design changes. Hence the data obtained from the crash tests is vital in design optimization of safety systems. The present study deals with the technologies involved …

Nondestructive Testing For Finding Out The Displacement Of Crack In Silicon Nitride, Sriharsha Kurra

Open Access Theses & Dissertations

Nondestructive testing (NDT) has become an increasingly vital factor in the effective conduct of research, development, design and manufacturing. Only with the appropriate use of nondestructive testing techniques, the benefits of advanced materials science can be fully realized. NDT has a wide range of industrial applications and various methods and techniques are employed to perform the nondestructive testing. The current work aims to demonstrate the nondestructive testing technique applied to determine the damage in silicon nitride. Ceramics are brittle materials and non destructive evaluation methods are required to assess the quality and reliability of them. A nondestructive evaluation technique has …

Finite Element Modeling Of Nondestructive Test Methods Used For Detection Of Delamination In Hot Mix Asphalt Pavements, Dante Mejia Munoz

Open Access Theses & Dissertations

For the simulation of detection of delamination this study focus on three NDT methods: Impact Echo, Impulse Response and Ultrasonic Surface Waves. The was evaluated and then a parametric study was elaborated.

An Enhanced Method For The Existing Bluetooth Pairing Protocol To Avoid Impersonation Attacks, Patricia Aidee Mendoza

Open Access Theses & Dissertations

As the use of the Bluetooth technology in wireless technologies such as computers, cell phones, personal digital assistants (PDAs), printers, digital cameras, PC peripherals, and headphones, among others, has enormously increased during this decade, it has also increased the need of employing a more secure and robust pairing protocol that protects the transfer of information between Bluetooth devices.

The existing Bluetooth pairing protocol starts when a Bluetooth device is set to be in discoverable mode and it is found by another device. After this step is completed, it initiates the pairing procedure by sharing some important device information, then by …

Semi-Automated Frame Transformations Using Fft Analysis On 2-D Images, Francisco Javier Osuna

Open Access Theses & Dissertations

Cassini entered Saturn's orbit on July 1, 2004 beginning a four-year exploration of Saturn. In 2008 the mission was extended, and Cassini continues to collect and transmit images and data collected during its mission. In order to accurately interpret images, it is necessary to know the location and orientation of the camera provided the field of view when the image was collected. While the mission managers provide initial estimates of this orientation, scientific analysis requires better estimates than the initial data provided. Navigation is a process for improving the estimation of the true camera pointing vector as determined by features …

Hybrid Ftth Optical Network Using Incoherent Optical Code Division Multiple Access, Joel Quintana

Open Access Theses & Dissertations

Over the past 20 years there has been extensive research on the application of spread spectrum multiplexing techniques for communications via optical fiber. Optical Code Division Multiplexing (OCDMA) is the technique that has exhibited the most promise as a primary multiplexing vehicle for the transition into all-optical processing of data, and as a supplement to other techniques such as Time Division Multiplexing (TDM) and Wave Division Multiplexing (WDM). OCDMA can be classified into incoherent OCDMA, where coding and detection is done on the basis of optical power, and coherent OCDMA where coding is done on a field amplitude basis. The …

Aluminum Hydride Compunds: A Theoretical And Experimental Spectroscopic Study, Layra E. Reza

Open Access Theses & Dissertations

None

Analysis Of Cluster Compute Nodes With Varying Memory Hierarchy Distributions, Jon Valentin Ramirez

Open Access Theses & Dissertations

This Thesis compares a Compute Node, a cluster compute node that can completely contain smaller processes within, but not larger ones, with a Memory Node, a cluster compute node that can fully contain large processes within main memory. The Compute Node and Memory Node are tested by executing matrix multiplication programs that range in size from small processes similar to jobs that can be run on a single workstation to large processes that would only fit entirely within a Memory Node. Memory was allocated using four types of memory allocation: static, external, dynamic, and automatic. This analysis provides a measure …

Optimization Of Flow For Plastic Pbt With 45% Glass And Mineral Fiber Reinforcement In An Injection Over Mold Process Using Taguchi, Cpk And Mold Flow Simulation Software Approaches, Israel Sanchez

Open Access Theses & Dissertations

This Thesis analyze the plastic injection molding parameters in order to identify which parameters significantly affects the flow properties of Polibuthylen Thereptalate with 45% glass/mineral reinforcement, and which levels are the best to use for those parameters. With the purpose of optimizing the plastic flow conditions in an injection mold to obtain parts free from short shots (term used to describe a plastic part that is incomplete due to the poor plastic flow in the mold runners and cavities).

The used approach is Taguchi design of experiments to define which parameters have significant effect on the response variable, and the …

Transition Metal Catalysts For Hydrodesulfurization Reactions Applied To Petroleum Industry, Brenda Torres

Open Access Theses & Dissertations

Catalysis plays a fundamental role in petroleum refining and basic petrochemical industries creating new routes in the development of industrial processes. Moreover, catalysis has become indispensable to the solution of environmental pollution problems and therefore on public health. World wide concerns for preservation of the environment has motivated the development of "Green" catalyst based technologies, to achieve a better utilization of petroleum resources and demands for cleaner transportation fuels. These environmental concerns have led to increasingly drastic regulations on sulfur, nitrogen and aromatics content in fuels. Sulfur content in the motor and diesel fuels is continuously reduced by regulations to …

Temperature-Induced Phenomena In Systems Of Magnetic Nanoparticles, Abdul Wazed Bhuiya

Open Access Theses & Dissertations

Magnetic nanoparticle ensembles have received a lot of attention, stemming in part from their current and potential applications in biomedicine and in the development of high-density magnetic storage media. Key to the functionality of these systems are microscopic structures and mechanisms that make them exhibit unique properties and behave differently from their bulk counterparts.

We studied microscopic structures and processes that dictate macroscopic properties, behavior and functionality of magnetic nanoparticle ensembles. As the temperature T strongly influences the magnetic behavior of these systems, we studied temperature dependent magnetic properties using AC-susceptibility and DC-magnetization measurements carried out over a broad range …

Experimental Investigation Of A Meso-Scale Axial Flow Pump, Jonathon Ray Bice

Open Access Theses & Dissertations

The scope of this work involves the testing of an experimental meso-scale axial flow pump intended for use in micro-spacecraft and micro-satellites. A setup was implemented to test pressure and flow characteristics at different velocities for three configurations of the pump. In addition, an alternate setup was used to test torque and efficiency. Computational fluid dynamics simulations were also conducted. The results are presented and analyzed to determine whether the pump is a viable alternative for the space industry.

Gis-Based Tool For Assessing Hydraulic Performance Of Drainage Infrastructure System In El Paso, Gema L. Camacho

Open Access Theses & Dissertations

Maintaining a city's storm-water drainage infrastructure system can be an overwhelming effort, especially when data is inaccurate, incomplete, or located in disparate sources. This was the case for the City of El Paso. This research was part of a project funded by the City of El Paso to enhance their GIS storm drainage infrastructure system. For the first task of the project, the GIS software was used to store stormwater drainage data into one convenient GIS file. A GIS framework was created during the first phase of the project. This GIS database contained drainage data (such as location, material, dimensions, …

Health Prognisis Of Electronics Via Power Profiling, Jonathan Amilcar Cervantes

Open Access Theses & Dissertations

The objective of this research is to investigate a new approach for the early detection of latent defects in electronic devices in the field. Reliability is assessed through the non-traditional approach of recording and evaluating the power profile of electronic devices within a deterministic state of operation. Traditionally, measuring the quiescent current (Iddq) of a device has been employed in manufacturing tests to detect defective parts prior to deployment to the field. However, the monitoring of the deterministic power signature (i.e. boot up or during a self-test routine) has never been exploited to monitor the health of a device in …

Characterization Of A Mems Accelerometer For A Highway Health Monitoring Ultra-Low Power Sensor, Karla Cecilia Enriquez

Open Access Theses & Dissertations

With the 2009 American Recovery and Reinvestment Act, government officials recognized the need to implement automated methods that reduce the cost of assessment projects and provide a long-term solution to monitor the structural health of bridges and highways. Although important research exists in the area of non-destructive evaluation, current road health monitoring efforts continue to be costly and time consuming. This Thesis focuses on the characterization of a MEMS accelerometer intended to be the basis of a novel ultra-low power sensing system to remotely asses the condition of highways. The architecture of a sensor prototype built to validate an algorithm …

Sustainable Development Extension Plan (Sudex): Community Mobilization Through Proactive Participation And Synergistic Alliance To Alliviate Poverty And Achieve Sustainable Self Sufficiency, Stephen Forbes

Open Access Theses & Dissertations

This Dissertation describes a sustainable development extension plan (Sudex Plan) to help communities in developing countries achieve Goal 1 of the United Nation's Millennium Development Goals (MDG). Goal 1 focuses on reducing poverty and hunger by 50% by the year 2015, but all the MDG are interrelated and one can not be achieved without considering the others, and to attain any is an empty accomplishment without ways to ensure that they can be sustained and continuously improved with the means to pass on the information, knowledge and lessons learned from community to community, generation to generation. The Sudex Plan is …

Insight Into The Physics Of Rupture: Dynamic Triggering Seismicity, Hector Gonzalez-Huizar

Open Access Theses & Dissertations

Seismic waves can trigger earthquakes and tremor at large distances from the causable event. Dynamic triggering occurs when the surface waves from large earthquakes change the stresses conditions on previously overstressed faults, promoting failure. To understand the causative stresses and environments behind dynamic triggering, we model the change in the stress field that the passing of Rayleigh and Love waves cause on a fault plane of arbitrary orientation relative to the direction of propagation of the waves, and apply a Coulomb failure criterion to calculate the potential of these stress changes to trigger seismicity. We apply our model to three …

Identification Of Human Gait Using Genetic Algorithm Tuned Fuzzy Logic, Abdallah Abdel-Rahman Hassan Mahmoud

Open Access Theses & Dissertations

Data mining is concerned with the discovery of useful hidden information in large databases. Classification is a data mining task producing rules in which a set of attributes in data predict the value of a class attribute. Classifiers usually produce a large number of rules, most of which are not interesting to the user. Rule interestingness is a decisive factor. However, evaluating rule interestingness is challenging as it involves both objective (data-driven) and subjective (user-driven) aspects.

In this research, a fuzzy genetic algorithm is proposed to discover classification rules that are both accurate and interesting. Continuous attributes are fuzzified so …

Comparison Of Older Mexican American Upper Extremity Reach Capabilities To Older Anglo Americans, Odi Mike Ikpe

Open Access Theses & Dissertations

The study aimed to investigate if there are upper extremity reach capability differences in older Mexican Americans and older Anglo Americans. The subjects were recruited and corresponded to the 2000 census track. Upper extremity reach capability was determined by analysis of 20 range of motion variables. A MANOVA analysis utilizing SPSS software was performed with age, gender and ethnicity as independent variables while height and 20 range of motion anthropometric measurements servings as dependent variables (responses). Ethnicity as a function of age was found to be significant in height, horizontal distance from buttock to hand, rotation of head to the …

Directional Analysis And Filtering For Dust Storm Detection In Noaa-Avhrr Imagery, Swapna Janugani

Open Access Theses & Dissertations

In this research, we propose spatio-spectral processing techniques for the detection of dust storms in 5-band NOAA-AVHRR imagery. The research is mainly focused on locating the dust sources and automatically finding the transport direction of the dust storm. Previous methods that use simple band math analysis have produced promising results but have some drawback in producing consistent results when low SNR images are used. Moreover, in seeking to automate the dust storm detection, the presence of clouds in the vicinity of the dust storm creates a challenge in being able to distinguish these two types of image texture. Our research …

Reduced Dimensionality Hyperspectral Classification Using Finite Mixture Models, Vikram Jayaram

Open Access Theses & Dissertations

Classification of HSI data is a challenging problem for two main reasons. First, with limited spatial resolution of HSI sensors and/or the distance of the observed scene, the images invariably contain pixels composed of several materials. It is desirable to resolve the contributions of the constituents from the observed image without relying on high spatial resolution images. Remote sensing cameras have been designed to capture a wide spectral range motivating the use of post-processing techniques to distinguish materials via their spectral signatures. Secondly, available training data for most pattern recognition problems in HSI processing is severely inadequate. Under the framework …

Spatio-Temporal Ecg Analysis For Localization Of Arrhythmias Using Precordial Ecg Leads And 128-Lead Systems, Eduardo Morales

Open Access Theses & Dissertations

A novel and state-of-the-art approach for the analysis of cardiac arrhythmias is proposed. Currently, the analysis of the electrocardiogram is only performed in the time-domain. The proposed method improves the electrocardiogram analysis by adding spatial properties. The spatial properties added to the electrocardiogram allow for the analysis of specific regions inside the human heart where cardiac arrhythmias are suspected to have occurred. In this Dissertation, the concept of electrocardiography was extended using advanced bioelectromagnetism theory. In concrete, the multiple dipole model of the human heart was used to extend the concept of electrocardiography from a temporal analysis to a spatial-temporal …

Effects Of Build Orientation, Aging, And Pre-Conditioning On Mechanical Properties For Stereolithography-Manufactured Astm Type I Specimens Using A Design Of Experiments Approach, Karina Puebla

Open Access Theses & Dissertations

With industry's growing focus on the rapid manufacturing (RM) of end-use products, rapid prototyping (RP) or layered manufacturing (LM) machines that were originally designed to build prototypes may now be required to build functional end-use products. To successfully accomplish the transition, the available materials utilized in RP must provide the performance required for RM. The specific technology used must also be capable of producing repeatable and reproducible parts in regards to mechanical and dimensional properties.

A design of experiments approach was performed to determine the effects of build orientation, aging, and pre-conditioning on the mechanical properties. To perform the investigations, …

Optimization Of A Strapdown Inertial Navigation System, Mario Ruiz

Open Access Theses & Dissertations

The focus of this Thesis is to find 21 error parameters in a Strapdown Inertial Navigation System (SINS) that would minimize objective functions or error functions to increase accuracy utilizing an optimization algorithm. The algorithm used is goal attainment by Gembiki which is a multi-objective optimization algorithm proven to outperform other optimization methods in terms of efficiency and accuracy over large numbers of problems. Simulations of a noise-free SINS mounted on an aircraft were done in a stationary and on the move scenario to simulate two conditions in which alignment could become necessary. The error parameters to find were sensor …

Computational Modeling Studies Of The Structures And Properties Of Organotin(Iv) And Stannyl-Thioether Systems With Comparisons To X-Ray Crystallography, Michelle R. Stem Joseph

Open Access Theses & Dissertations

Controlling the toxic effects of organotin(IV) compounds involves engineering the structure of the molecules to optimize their properties. Molecular engineering, coupled with improved capabilities to generate reliable computational optimization models (COMs), will enable researchers to have greater success at harnessing the highly specific cytotoxicity of organotins. For example, as the thio_n ligand phenyl groups were replaced with Cl atoms, the S-Sn intramolecularity was strengthened, the bond distance decreased, and the stannyl tetrahedral structure was deformed from its triphenyl conformation. With each substitution, conformation deformations lowered the damaging bioactivity levels of thio_n. Bonding various ligands to organotin(IV) compounds …

Experimental Study Of The Response Of Semiconductor Detectors For Edxrf Analysis., Sunil Kumar Valaparla

Open Access Theses & Dissertations

This present work relates to the study and characterization of the response function of an energy-dispersive x-ray spectrometer. The problems of energy, efficiency and resolution calibration of the system operating in the energy (5-60 keV) range are discussed. We present the operation characteristics of the portable pyro-electric x-ray generator (COOL-X) and the application of the calibrated response spectrum in the elemental analysis using X-ray Fluorescence (XRF).

We study the response of the Si(Li)-Pin XR-100CR semiconductor detector to low energy photons. The photopeak efficiency was determined experimentally by using radioisotopes and compared against a theoretical efficiency curve. The efficiency for gamma …

Characterization Of High Resolution Range And Doppler Chaotic Ladar, Berenice Verdin

Open Access Theses & Dissertations

Compared to high range resolution radar systems, chaotic LADAR (laser detection and ranging) has the potential of providing an increase in range-Doppler resolution by several orders of magnitude.

The purpose of this project is to determine system parameters and signal processing schemes required to build a high resolution chaotic LADAR. Specifically, the LADAR is based on a semiconductor laser that generates a wideband chaotic signal via optical feedback. The behavior of the laser output is modeled by changing the control parameters of the delay differential equations that dictate the behavior of the laser output. Depending on the feedback level and …

Exploring Poly(Ethylene Glycol) As A Suitable Material For Peripheral Nerve Regeneration Scaffolds Manufactured By Stereolithography, Nubia Zuverza

Open Access Theses & Dissertations

One of the challenges in tissue engineering is to have spatial and temporal control over the biological elements within a scaffold used to guide regeneration for example of transected nerves. Some of the physical and chemical characteristics to regulate include incorporation of bioactive domains and release of chemical signals. This study presents the use of stereolithography (SL) to incorporate localized domains for cell adhesion in addition to include releasable nerve growth factor (NGF) in the process of building poly(ethylene glycol)diacrylate (PEGda) hydrogel scaffolds. Besides providing sites for cell attachment, an ideal nerve guidance conduit (NGC) should be able to release …