Engineering Commons^™

Finding Least Expensive Tolerance Solutions And Least Expensive Tolerance Revisions: Algorithms And Computational Complexity, Inna Pivkina, Vladik Kreinovich

Departmental Technical Reports (CS)

For an engineering design, tolerances in design parameters are selected so that within these tolerances, we guarantee the desired functionality. Feasible algorithms are known for solving the corresponding computational problems: the problem of finding tolerances that guarantee the given functionality, and the problem of checking whether given tolerances guarantee this functionality.

In this paper, we show that in many practical problems, the problem of choosing the optimal tolerances can also be solved by a feasible algorithm. We prove that a slightly different problem of finding the optimal tolerance revision is, in contrast, computationally difficult (namely, NP-hard). We also show that …

Wavesurfer: A Tool For Sound Analysis, Ernesto Medina, Thamar Solorio

Departmental Technical Reports (CS)

Researchers in the Interactive Systems Group at UTEP have been using a research tool called Didi for some time now. It was originally designed to be easily adaptable. This tool has proven to be adaptable as it has been changed by different researchers to suit particular needs. As a result, multiple versions of the program exist. In addition to this, the tool only works in Linux and has grown quite a bit. To solve these problems, the different versions could have been consolidated into one program and modified to produce a version that worked on other platforms, or another program …

Biodiesel Related State Incentives, Josh Zahn

Industrial Agricultural Products Center: Publications and Information

Contents:

• National Perspective • Discussion of Various Forms of Incentives • Regional Incentives

Self-Assembly Of Nanoparticles In Photonic Crystal Cavities For Optoelectronic Devices, Geetha Thiruvengadam

Material Science and Engineering Theses - Archive

Photonic crystals (PhC) offer many advantages in optoelectronics field. The focus of this thesis is to investigate a self assembly process for the formation of thin film based one-dimensional PhC and the integration of nanoparticles with two-dimensional PhC. Nanoparticles like SiO2, TiO2, PolyStyrene, and PbSe (with different surface properties) were subjected to different experiments. Various techniques, such as spin coating, immersion technique, evaporation induced assembly technique, have been carried out by varying parameters like time, temperature, position of the substrate, etc.,. An optimized method for the fabrication of 1D PhC was found to be evaporation induced Self-Assembly method by varying …

Uncertainty Characterization Of Orbital Debris, Jolanta Matusewicz

Mechanical and Aerospace Engineering Theses - Archive

The increase of orbital debris in the low Earth orbit is a concern for the space industry. Spacecraft and satellites are at risk of collision with orbital debris. Collisions can damage sensitive components or result in catastrophic failure. Organizations such as the United States Space Command are responsible for tracking orbital debris using ground based sensor sites located around the world. Orbit determination techniques are used to estimate the position and velocity of the orbit using range, azimuth, and elevation measurements obtained from the sensors. Nine sensors from the Space Surveillance Network are simulated to track a debris object in …

Analysis And Design Of A Piezoelectric Micro-Actuator, Po-Shiun Chen

Mechanical and Aerospace Engineering Theses - Archive

Micro-grippers are usually fabricated of silicon using traditional semiconductor manufacturing processes and actuated based on thermal energy input causing their temperature to substantially increase and render unsuitable for certain applications such as biological tissue handling. In this research work, the design of a micro-gripper using piezoelectric ceramics (PZT) is presented as an alternative to silicon based micro gripper. The design procedure utilized ANSYS, a Finite Element Method based software tool to verify simple PZT models and subsequently evaluate the stroke for a family of configurations. The configurations were further explored and optimized considering that the fabrication would be performed using …

Mems Packaging: Fluxless Soldering And Reliability Assessment, Amit L. Patil

Mechanical and Aerospace Engineering Theses - Archive

This thesis presents process development and reliability assessment of the fluxless packaging of the MEMS devices. This packaging consists of metallized Kovar package with side wall of same material and circular holes for the optical fiber interconnect between the microstructures on the chip and the macro-environment. The back of the MEMS chip and the soldering part of the optical fiber is metallized. A thin solder perform is placed between the chip and the metallized package to attach the chip and a circular solder perform is used to attach the fiber to the metal substrate. The soldering process is fluxless hence …

Spacecraft Formation Flight: Analysis Of The Perturbed J2-Modified Hill-Clohessy-Wiltshire Equations, Jeffery Scott Ginn

Mechanical and Aerospace Engineering Theses - Archive

With the recent technological gains made in satellite design and manufacturing, there has been great interest in utilizing a cluster of satellites to perform the same tasks performed by larger satellites. Historically, this has been done utilizing the Clohessy-Wiltshire equations, or the Hill's equations, as a benchmark for understanding the physics of the relative motion between two spacecraft. A variety of different models have been derived and implemented to study the relative motion dynamics since the Hill-Clohessy-Wiltshire (HCW) equations. Some of these models, like the HCW equations, are linearized and have analytical solutions. These models make the underlying physics due …

Effect Of Crac Location On A Fixed Rack Layout Of A Data Center, Vishwas Bedekar

Mechanical and Aerospace Engineering Theses - Archive

Microprocessor driven escalation of thermal management needs has resulted in significant cooling challenges at the data center facility level, which can house thousands and tens of thousands of heat producing processors. Raised floor air ducting is the most common configuration, where chilled air from the air conditioning units is forced into the room via a under floor plenum and through perforated tiles on the floor. The hot air from the racks finds its way to the top of the air conditioning units and is then cooled and blown into the under floor plenum. The temperature at inlet of the racks …

Preparation And Characterization Of Doped Zinc Oxide, Yogeeswaran Ganesan

Material Science and Engineering Theses - Archive

Cathodic electrodeposition was used to prepare thin films of ZnO doped with Cd, from oxygenated KCl electrolyte containing ZnCl2 and CdCl2 in various molar ratios ranging from 0 mM to 5.0 mM each. Evidence for doping was obtained from X-ray powder diffraction, diffuse reflectance, chronopotentiometry, and X-ray photoelectron spectroscopy data. The Cd-doped ZnO samples showed a superior photoresponse relative to undoped ZnO. Cadmium- and indium-doped ZnO were prepared by combustion synthesis using CdCl2 and InCl3 as dopant precursors along with zinc nitrate and urea as the combustion mixture. The doped samples were compared and contrasted with undoped ZnO using scanning …

Characterization Of Cemented And Fiber-Reinforced Rap Aggregate Materials For Base/ Sub-Base Applications, Carlos A. Ordonez

Civil Engineering Theses - Archive

The engineering product known as RAP is a bonded base and sub-base material produced by the process of blending crushed recycled construction and demolition waste and debris to specified gradation requirements, and by bonding these with a fine silica Portland cement matrix at optimum moisture for compaction density. RAP has a great potential as an economically, environmentally, and structurally sound alternative to non-bonded materials conventionally used for base/sub-base applications in pavement engineering. The present work is aimed at thoroughly testing the engineering properties of RAP product in order to assess its suitability as a structurally sound and environmentally safe material, …

Flow Rate Measurement Of In Situ Perfusion Through The Aqueous Humor Outflow Network, Noel Ortiz Lawrence

Bioengineering Theses - Archive

A system was developed to measure the instantaneous perfusate flow rate through the aqueous humor outflow network of a human eye, while under constant pressure. The system monitors real-time weight changes of a perfusate reservoir associated with perfusate flow through the aqueous humor outflow network. The recorded weight changes of the reservoir are used as an indicator of flow rates. Methods to determine time and flow rate resolution and to control for evaporation were also developed. The system is capable of measuring flow on a uL/min scale; determined by the following model, which also includes a range of uncertainty (implies …

Detection Of Sleep Disordered Breathing Using Electroencephalography, Priya Xavier

Bioengineering Theses - Archive

This study investigates the application of Electroencephalography (EEG) to detect Sleep disordered breathing (SDB) using power spectral analysis. A preliminary study was performed on 13 subjects (ages: 49.08 ± 8.82) previously diagnosed with OSA. Power spectral analysis was performed and centered on apnea/hypopnea event terminations. The normalized power changes between the frequency bands delta, theta, alpha and sigma were calculated using the Welch Averaging Periodogram method between 10 s of EEG data before the event termination and 10 s of EEG data after event termination. A significant decrease in normalized delta power and a significant increase in normalized theta, alpha …

Characterization And Feasibility Study Of A Near Infrared Ccd Imager For Monitoring Tumor Hemodynamics, Manan Goel

Bioengineering Theses - Archive

Prostate cancer is one of the most common types of cancers diagnosed among North American men. Chemotherapy is generally used to target advanced metastatic prostate cancer. Near infrared spectroscopy (NIRS) has been previously investigated to monitor the hemodynamic changes in rat prostate tumors; however, the previous study with NIRS is limited by its spatial resolution. The goal of this study is to characterize an NIR, CCD imager and to explore the feasibility of using the CCD imager to non-invasively monitor hemodynamic changes in rat prostate tumors during gas intervention. Firstly, studies were conducted to characterize the CCD imager and understand …

Impact Of A Pre-Combustion Retrofit Device On Vehicular Emissions: A Case Study, Sri Harsha Kanukolanu

Civil Engineering Theses - Archive

Vehicular emissions are a major cause of air pollution in the cities worldwide. Increased numbers of vehicles and the vehicle miles traveled by them every year means that the emissions are going to have a detrimental effect on the life and environment of this planet. Various control strategies are employed by the transportation and air quality managers at the state and regional levels to improve the ambient air quality. This research was conducted as part of the North Central Texas Council of Governments' Aftermarket Technology and Fuel Additive Research Program, its effort to make the DFW region's air cleaner. The …

Effectiveness Of Signal Coordination As An Emission Reduction Measure For Vehicles, Rajashi I. Parikh

Civil Engineering Theses - Archive

Air Pollution is a significant health and environmental concern. Vehicular emissions are major contributors to many air pollution problems. There is growing interest in reducing carbon dioxide emission because of the alarming increase in the pollution caused by petroleum resulting global warming issue. Various studies have found that U.S vehicles emit half of the CO2 emitted from vehicle all over the world. Dallas Fort Worth is a non-attainment area for ozone and it is required to achieve NAAQS standards by 2010. NOx and VOCs from the automobile are a major precursor of ozone formation in the atmosphere. Traffic signal retiming …

Assessment Of Soil-Water Retention Properties Of Lime And Cement Treated Clays, Harshavardhan Reddy Thudi

Civil Engineering Theses - Archive

The soil-water characteristic curve (SWCC) of unsaturated soils has considerable importance in the analysis of geotechnical engineering problems involving soils that remain under partially saturated conditions throughout any given year. The SWCC reflects the behavior of unsaturated soils with regard to its hydraulic conductivity, shear strength, and volume change behavior. Numerous investigations have been undertaken in recent decades to extend the unsaturated soil mechanics principles into conventional engineering practice. The soil-water characteristic curve (SWCC) has become a widely used experimental means for assessing fundamental properties of unsaturated soils for a wide range of suction values. However, a limited number of …

Optimization Of Hydrogen Filling Station, Vishal Bhan

Electrical Engineering Theses - Archive

After experiencing the price hikes in the fuel and electricity, renewable energy is considered as one of the most attractive alternatives for future utility industry. Also, Hydrogen via renewable energy is of interest due to the environmental concern when compared with traditional fossil fuels. The Energy Bill of 2005 has included an authorization of $3.7 billion for hydrogen and fuel cell research and development. Further, hydrogen fuel cell vehicles (FCVs) are currently in the pre-production stage of development and the infrastructure needs to support them. Hence to overcome issues like price hike, exhaustion of crude oil and to gain appreciation …

Emulation Of Asic Based Network Processor On A Fpga Platform, Sharada Vajja

Electrical Engineering Theses - Archive

ABSTRACT Exponential increase of device sizes and complexity of ASICs mandate the need for design verification to meet timing specifications and functionality requirements. Verification techniques are broadly implemented in three categories viz., simulation, verification using commercial emulators and FPGA based prototyping. An Intel architecture based network processor, to be taped out in the near future, is being emulated on FPGA based platform. The basic blocks of the Network Processor, for instance, the Memory Controller Hub and I/O controller Hub were synthesized to be configured on FPGAs. The work involved synthesizing the design, partitioning it on multiple FPGAs and pin multiplexing …

Mitigation Of Window Effects In Inverse Synthetic Aperture Radar (Isar) Imagery Using Multi-Resolution Technique, Suman Kumar Gunnala

Electrical Engineering Theses - Archive

A method using Multi-Resolution technique for window effect mitigation in ISAR imagery, which occurs due to finite extent data, is presented in this work. Proposed method is supported with quantitative measure using both Structural Similarity (SSIM) and Mean Square Error (MSE). In addition, above index measures were used to determine the best choice of wavelet basis for window effect mitigation. Complete angular window and partial angular window are used as two cases to demonstrate the validation of above contributions. Scattering measurements of different test sets were done to validate the approach. Results which include reconstructed images and quantitative index measures …

Analysis Of Traffic Crash Data In Kentucky (2001 – 2005), Eric R. Green, Kenneth R. Agent, Jerry G. Pigman

Kentucky Transportation Center Research Report

This report documents an analysis of traffic crash data in Kentucky for the years of 2001 through 2005. A primary objective of this study was to determine average crash statistics for Kentucky highways. Average and critical numbers and rates of crashes were calculated for various types of highways in rural and urban areas. These data can be used in Kentucky’s procedure to identify locations that have abnormal rates or numbers of crashes. The other primary objective of this study was to provide data that can be used in the preparation of the problem identification portion of Kentucky’s Annual Highway Safety …

A Study Of Finite State Machine Coding Styles For Implementation In Fpgas, Nader I. Rafla, Brett L. Davis

Electrical and Computer Engineering Faculty Publications and Presentations

Finite State Machines (FSM), are one of the more complex structures found in almost all digital systems today. Hardware Description Languages are used for high-level digital system design. VHDL (VHSIC Hardware Description Language) provides the capability of different coding styles for FSMs. Therefore, a choice of a coding style is needed to achieve specific performance goals and to minimize resource utilization for implementation in a re-configurable computing environment such as an FPGA. This paper is a study of the tradeoffs that can be made by changing coding styles. A comparative study on three different FSM coding styles is shown to …

Oxidase-Coupled Amperometric Glucose And Lactate Sensors With Integrated Electrochemical Actuation System, Jongwon Park, Chang-Soo Kim, Minsu Choi

Electrical and Computer Engineering Faculty Research & Creative Works

Unpredictable baseline drift and sensitivity degradation during continuous use are two of the most significant problems of biosensors including the amperometric glucose and lactate sensors. Therefore, the capability of on-demand in situ calibration/diagnosis of biochemical sensors is indispensable for reliable long-term monitoring with minimum attendance. Another limitation of oxidase enzyme-based biosensors is the dependence of enzyme activity on the background oxygen concentration in sample solution. In order to address these issues, the electrolytic generation of oxygen and hydrogen bubbles were utilized 1) to overcome the background oxygen dependence of glucose and lactate sensors and 2) to demonstrate the feasibility of …

Analysis And Optimal Design Of Beams Using Radial Basis Function, Yung-Kang Sun

Mechanical and Aerospace Engineering Dissertations - Archive

The application of Multiquadric Radial Basis Function (MQ RBF) in the analysis and optimal design of beams are addressed in this dissertation. For static analysis, a new Least Square Collocation (LSC) method is introduced. For buckling and vibration analysis, Rayleigh-Ritz analysis procedures are presented using MQ RBF basis function. Numerical results show that LSC can provide better results than the classical collocation method when the same number of collocation points are used. In vibration analysis, MQ RBF-based Rayleigh-Ritz can be used to calculate natural frequency accurately for several hundred modes. The important question of choosing shift parameters is discussed and …

Enhancement Of Cryoinjury By Use Of Eutectic Crystallization Of An Amino Acid Adjuvant, Chuo-Li Wang

Mechanical and Aerospace Engineering Theses - Archive

Enhancement of cryoinjury by use of eutectic formation was investigated to improve the efficacy of cryosurgery. Although the enhancement of cryoinjury associated with eutectic crystallization of sodium chloride (NaCl) has been demonstrated, its advantage can be maximized with adjuvants which are biocompatible and have higher eutectic temperature than NaCl. In this study, the feasibility of glycine, which is less toxic and have higher eutectic temperature than NaCl, was tested. Two groups of MCF-7 human breast cancer cell were suspended in isotonic saline with glycine, then were frozen and thawed on a directional solidification stage in the same protocol except that …

Hourly Weather Forecast Analysis, Sothaya Rasmidatta

Electrical Engineering Theses - Archive

Today, internet becomes one of the most important resources for useful information. However, since the authentic of the information is difficult to verify, one also has to take precaution when getting information from the internet. Utility companies need to forecast their load for unit commitment scheduling and system planning. The traditional approach for neural network forecasting relies on the temperature forecasting information from a single source. The customer loads are closely correlated with the temperature. Therefore, the accuracy of the load forecasting is affected by the temperature forecasting errors. The objective of this thesis is to reduce the temperature forecasting …

Novel Techniques Of Fabricating Porous, Biodegradable Polymer Scaffolds For Sustained Drug Release, Mayur B. Uttarwar

Bioengineering Theses - Archive

Two types of porous scaffolds were made from biodegradable polymers and their drug release trends and rates were studied. In first method, the emulsion of PLLA in chloroform solution and PVA and acetaminophen in de-ionized water solution was made. The emulsion was blended with PLLA solution. The resultant emulsion was freeze vacuum dried. The drug release study was conducted in-vitro. In the second method, scaffolds had three layers. The top and bottom layers were made by blending PLLA solution with PVA solution. The middle layer was made by blending PLLA solution with a mixture of PVA and Acetaminophen in de-ionized …

Drug Loaded Polymeric Blends For Developing Vascular Stents, Anup C. Dasnurkar

Bioengineering Theses - Archive

In-stent restenosis and neo-intimal hyperplasia are long-term limitations of metallic stents. Local delivery of medications to transluminal angioplasty sites to prevent restenosis is receiving worldwide attention. Development of localized application of antiproliferative agents, and gene therapy via bio-degradable coatings on metallic substrates proved to be successful in reducing restenosis but was limited by the problems of limited drug load, etc. The presence of a foreign object for a long period of time may lead to the further narrowing of the treated lesion. The rationale for usage of bioresorbable drug eluting stents is the ability to store large quantities of drug …

Development Of An In-Vitro Assay For Neurotrophin-Induced Segregation Of Nociceptive And Proprioceptive Sensory Axons, Ebrahim Shabbir Bengali

Bioengineering Theses - Archive

Peripheral nerves have the capacity for regeneration and if properly repaired, axon extensions can regenerate even across gaps caused by peripheral nerve loss. Complete functional recovery after gap injury repair remains suboptimal due to the erroneous pathways taken by the regenerating axons leading to aberrant target innervation. A segregation of axonal types can facilitate efficient target direction and innervation leading to improved functional recovery. Novel two-dimensional and three-dimensional Y-shaped assays were developed to test whether the nociceptive and proprioceptive sensory axons from the dorsal root ganglia could be segregated through specific neurotrophin inducement; namely NGF and NT-3 respectively. A large …

Development Of Targeting Nanoparticles Mimicking The Adhesive Properties Of Platelets, Arthur Lin

Bioengineering Theses - Archive

The development of biodegradable nanoparticles as drug delivery vehicles presents an improved avenue for intracellular targeted drug delivery. Biodegradable nanoparticles have demonstrated an ability to provide controllable, sustained drug release in vitro. However, in vivo studies have shown that nanoparticles are not effective at adhering to vascular walls under shear stress. The purpose of this study was to investigate methods to improve cellular uptake and targeting of nanoparticles in activated or inflamed endothelial cells (ECs) under fluid shear stress and to determine whether the material properties of a biodegradable polymer, poly (lactic-co-glycolic) acid (PLGA), affected cellular uptake. The hypothesis for …