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Articles 2041 - 2070 of 3180

Full-Text Articles in Engineering

Sparsity Enhanced Reconstruction Algorithms For Diffuse Optical Tomography, Jixing Yao Jan 2013

Sparsity Enhanced Reconstruction Algorithms For Diffuse Optical Tomography, Jixing Yao

Electrical Engineering Dissertations - Archive

Conventional reconstruction algorithms for diffuse optical tomography (DOT) is based on Tikhonov regularization method and the simple white Gaussian noise (WGN) assumption. These approaches usually lead to the following problems: 1. The reconstructed images are blurry; 2. In 3D reconstruction problems, the reconstructed objects are usually in the wrong depths; 3. The shape of a reconstructed object might be different from its original one due to the noise.In this work, after study the nature of DOT images as well as the data acquisition process, several sparsity regularization related reconstruction methods were developed to improve the spatial resolution as well as …

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Reliability Unit Commitment In Ercot Nodal Market, Hailong Hui Jan 2013

Reliability Unit Commitment In Ercot Nodal Market, Hailong Hui

Electrical Engineering Dissertations - Archive

The Electric Reliability Council of Texas (ERCOT) is the independent system operator (ISO) that ensures a reliable electric grid and efficient electricity markets in the ERCOT region. ERCOT has successfully transited from a zonal market to an advanced nodal market since Dec. 2010. In the new ERCOT nodal wholesale market, a reliability unit commitment (RUC) process has been designed and implemented to ensure transmission system reliability and security. The main objective of RUC is to ensure that enough resource capacity, in addition to ancillary service capacity, is committed in the right locations to reliably serve the forecasted load in the …

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Nanostructured Surfaces Using Thermal Nanoimprint Lithography: Applications In Thin Membrane Technology, Piezoelectric Energy Harvesting And Tactile Pressure Sensing, Bhargav Pradip Nabar Jan 2013

Nanostructured Surfaces Using Thermal Nanoimprint Lithography: Applications In Thin Membrane Technology, Piezoelectric Energy Harvesting And Tactile Pressure Sensing, Bhargav Pradip Nabar

Electrical Engineering Dissertations - Archive

Nanoimprint lighography (NIL) is emerging as a viable contender for fabrication of large-scale arrays of 5-500 nm features. The work presented in this dissertation aims to leverage the advantages of NIL for realization of novel Nano Electro Mechanical Systems (NEMS). The first application is a nanoporous membrane blood oxygenator system. A fabrication process for realization of thin nanoporous membranes using thermal nanoimprint lithography is presented. Suspended silicon nitried membranes were fabricated by Lowe-Pressure Chemical Vapor Deposition (LPCVD) in conjunction with a potassium hydroxide-based bulk michromachining process. Nanoscale features were imprinted into a commercially available thermoplastic polymer resist using a prefabricated …

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A Low-Noise, Low-Power Cmos Amperometric Circuit For Glucose Sensing, Niranjan Karandikar Jan 2013

A Low-Noise, Low-Power Cmos Amperometric Circuit For Glucose Sensing, Niranjan Karandikar

Electrical Engineering Dissertations - Archive

Diabetes is disorder associated with an insufficiency of insulin secretion. Large number of people around the world suffers from this disorder which can result into damages to eyes, kidneys, nerves and even death. One of the most common methods to detect the diabetes is to monitor the levels of glucose is the blood stream. Other biological fluids like tear fluid can also be used to detect levels of glucose. With emergence of MEMS technology several biosensors are developed, less invasive or non-invasive, which can detect these glucose levels from blood or tear. Central idea behind the developments of these biosensors …

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Implementation Of An Adaptive Block Filter On Sub-Blocks Of A Macroblock In H.264/Avc, Bhavana Prabhakar Jan 2013

Implementation Of An Adaptive Block Filter On Sub-Blocks Of A Macroblock In H.264/Avc, Bhavana Prabhakar

Electrical Engineering Theses - Archive

Plenty of coding tools are being developed to boost the efficiency of H.264/AVC. Some of these tools are implemented in the key technical area (KTA). The adaptive interpolation filter (AIF) [3], the high precision interpolation filter [5], and the adaptive loop filter (ALF) [4] have already been introduced in order to provide a more precise reference picture. Other efficient coding methods, such as the motion vector competition [6] and the extended macro-block (MB) [7], are also implemented in the KTA [16].In order to improve the coding efficiency of H.264/AVC, an adaptive prediction block filter (APBF) based on Wiener filter is …

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Embedded And Rf Powered Implantable Medical Device For Gastric Electrical Stimulation (Ges), Guru Moorthy Ravi Jan 2013

Embedded And Rf Powered Implantable Medical Device For Gastric Electrical Stimulation (Ges), Guru Moorthy Ravi

Electrical Engineering Theses - Archive

Gastric electrical stimulation (GES) has attracted significant attention in the treatment for Gastroparesis-a common disorder caused in patients suffering from diabetes, cancer and Parkinson's disease. Symptoms include vomiting, nausea, abdominal bloating etc. due to loss of motility in the stomach muscles. GES uses electrical pulses on the stomach tissues to help regain normal motility and reduce the symptoms. Conventional gastric stimulator needs a long surgery to be implanted and it is a big pacemaker like device that runs by a non-rechargeable battery. It has to be replaced once the battery gets exhausted every 5 to 6 years. Hence another round …

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Diagnosing Wi-Fi Association Issues And Optimizing Network Performance, Suma Subbarao Jan 2013

Diagnosing Wi-Fi Association Issues And Optimizing Network Performance, Suma Subbarao

Electrical Engineering Theses - Archive

Extensive deployment of Wi-Fi networks at homes and public places has triggered research interest in several aspects of Wi-Fi technology like deployment strategies and optimization. People use Wi-Fi or 802.11 networking, to connect their computers at home or office for instant internet access and it is a common scenario to have faced association and network congestion problems. Finding appropriate solution to these issues is a challenging task. In this thesis, an attempt has been made to solve Wi-Fi related concerns through a novel approach. Diagnosing problems occurring during the association process with the network and getting better throughput from the …

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A Cmos Switched Capacitor Based Amperometric Readout Circuit For Microneedle Glucose Sensor, Sunil Govardhan Jan 2013

A Cmos Switched Capacitor Based Amperometric Readout Circuit For Microneedle Glucose Sensor, Sunil Govardhan

Electrical Engineering Theses - Archive

Accurate regulation of glucose metabolism is one of the key factors in keeping a healthy state among mammalians. Increase in failure of this natural blood glucose regulatory mechanism has propelled the research for improvements in blood glucose measurement and its regulation. Also, advancement in the research of internet of things has increased the demand for smart sensors creating a revolution in health care industry and which has inturn led to the improvement in point-of-care testing.Therefore in this thesis work a microneedle glucose sensor is chosen as it can be fabricated by MEMS process which allows it to be easily integrated …

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Swcc And Clay Mineralogy Based Models For Realistic Simulation Of Swell Behavior Of Expansive Soils, Aravind Pedarla Jan 2013

Swcc And Clay Mineralogy Based Models For Realistic Simulation Of Swell Behavior Of Expansive Soils, Aravind Pedarla

Civil Engineering Dissertations - Archive

Predicting the volume change behavior of expansive soils has been a major challenge to the engineers in the past few years, due to the intricate couple effects caused by different soil composition parameters toward swelling. Hence, the behavior of an expansive soil is better understood with its inherent composition parameters. For this research, eight natural expansive clays have been sampled from different active swell zones across The United States. Basic soil classification was performed on these soil to identify the high plasticity and low plasticity clays. The swell behavior of these clays are studied using different testing methods and initial …

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Non-Linear Finite Element-Based Material Constitutive Law For Zero Slump Steel Fiber Reinforced Concrete Pipe Structures, Alena Mikhaylova Jan 2013

Non-Linear Finite Element-Based Material Constitutive Law For Zero Slump Steel Fiber Reinforced Concrete Pipe Structures, Alena Mikhaylova

Civil Engineering Dissertations - Archive

This study presents a comprehensive investigation of performance and behavior of steel-fiber reinforced concrete pipes (SFRCP). The main goal of this study is to develop the material constitutive model for steel fiber reinforced concrete used in dry-cast application. To accomplish this goal a range of pipe sizes varying from 15 in. (400 mm) to 48 in. (1200 mm) in diameter and fiber content of 0.17%, 0.25%, 0.33%, 0.5%, 0.67% and 83% by volume were produced. The pipes were tested in three-edge bearing condition to obtain the load-deformation response and overall performance of the pipe. The pipes were also subjected to …

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Evaluation Of Quality And Sustainability Incentives To Optimize The Indonesian To The United States Crude Oil Supply Chain, Restu Purwaningtyas Sunarto-Bussey Jan 2013

Evaluation Of Quality And Sustainability Incentives To Optimize The Indonesian To The United States Crude Oil Supply Chain, Restu Purwaningtyas Sunarto-Bussey

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

The New York Times explained that the United States increased its dependence on oil from Saudi Arabia by more than 20 percent last year (Krauss 2012). The United States of Energy Information Administration (U.S. EIA) stated that oil from Saudi Arabia was accounted for 14 percent of the U.S. crude oil and petroleum products in 2012 ("Oil: Explained" 2012). This is problematic due to the fact that 14 percent of the U.S. net crude oil and petroleum products imports come from one country, Saudi Arabia. What happens to the U.S. economy when Saudi Arabia manipulates demand and possibly stops exporting …

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Gaseous Corrosion In Hard Disk Drive: A Computational Study, Hardik Shah Jan 2013

Gaseous Corrosion In Hard Disk Drive: A Computational Study, Hardik Shah

Mechanical and Aerospace Engineering Theses - Archive

HDD is the largest digitally encoded data storage device. HDD is used to store digital data in data centers, computers and laptops. A typical HDD consists of a casing, an actuator arm, actuator axis, head, platters, power connectors, and jumper pins. The platter is made up of non-magnetic material and is covered by magnetic material, which stores the data. The magnetic heads are mounted on a moving actuator arm to read and write the data. One of the modes of failure of a HDD is corrosion. The parts of the HDD are corroded by coming in contact with the contaminants. …

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Chemoelastoplastic Analysis Of A Copper-Graded Silicon Nanorod For Lithium-Ion Battery Anode Application, Chao Ji Jan 2013

Chemoelastoplastic Analysis Of A Copper-Graded Silicon Nanorod For Lithium-Ion Battery Anode Application, Chao Ji

Mechanical and Aerospace Engineering Theses - Archive

Lithium-ion batteries are currently widely used in electronics, electrical vehicles and other devices/machines. Along with the mounting demand for much improved performance in these developing technological fields, silicon was recognized to possess much higher energy capacity when used as an anode than graphite that is currently used. However, there occurs colossal volume expansion of silicon anode during the lithiation process. The material consequently suffers enormous stresses, especially, at the interface with a current collector, which deteriorate the device quickly during cycling. To prevent the active material (Si) from falling off from a current collector, nanoengineering strategies have been suggested, including …

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Application Of Phase Change Material In Sustainable Cooling Of Data Centers, Nikhil Dhiman Jan 2013

Application Of Phase Change Material In Sustainable Cooling Of Data Centers, Nikhil Dhiman

Mechanical and Aerospace Engineering Theses - Archive

The ever increasing information technology heat load and data center cooling energy are the main reasons to investigate the performance of microencapsulated phase change slurry over other heat transfer fluids. In recent years, more effort is being made on the development of a new technique to use the phase change materials as pump-able heat transfer fluid and as heat storage system.Microencapsulated phase change slurry is dispersion where the phase change material, microencapsulated by a polymeric capsule, is dispersed in water. Compared to water, these new fluids have a higher heat capacity during phase change and a possible enhancement, as a …

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Thermal Management Method For Foil Bearings In Turbine Hot Section, Tejas Devidas Patil Jan 2013

Thermal Management Method For Foil Bearings In Turbine Hot Section, Tejas Devidas Patil

Mechanical and Aerospace Engineering Theses - Archive

Recently, Air Foil Bearings (AFB) are gaining higher industrial acceptance in micro-turbo machinery. AFB show high speed operating capability and environmental friendly operation in comparison to rolling element bearings. Utilization of ambient air as a lubricant eliminates maintenance of a pressurized oil lubricating system. AFBs are therefore a feasible alternative to oil lubricated bearings in small machines. High speed operation results in thermal management issues which can be solved through a suitable cooling mechanism. Axial cooling by passing air through bearing support structure (called bump foils) is the most commonly used. In this method, cooling is achieved in the heat …

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Immersion Cooling Of High End Data Center Server And Validation Through Experiments, Harsh Patel Jan 2013

Immersion Cooling Of High End Data Center Server And Validation Through Experiments, Harsh Patel

Mechanical and Aerospace Engineering Theses - Archive

Despite recent improvements in data center cooling efficiency such as hot and cold aisle and air side economizer, air cooling may not have the capacity to cool high end racks such as from IBM's NetBAY42 (150Kw and above). Increasing computer capabilities in data center has resulted in increase in rack power density per square ft as indicated by the latest uptime. The cooling of such high powered servers and corresponding racks poses a significant challenge to thermal engineers.The use of immersion cooling is novel approach for data center cooling. In this study after some modification high powered server is fully …

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Real Time Motion Control For Natural Human Robot Interaction, Suresh Sampathkumar Jan 2013

Real Time Motion Control For Natural Human Robot Interaction, Suresh Sampathkumar

Electrical Engineering Theses - Archive

In this thesis, we present the research work performed with various robots including Android PKD, Zeno and the Atlas robot. The main focus of this thesis is to develop algorithms for vision based natural human robot interaction in real time. Zeno is a childlike robot that we use for the research related to Autism in children. Children with Autism who lack motor skills tend to shy away from humans. In this project we use the robot Zeno that is capable of facial expressions, arm and body motions to teach motor skills to them. For this purpose we developed a program …

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Transfer-Printed Photonic Crystal Nanomembrane Fano Resonance Filters And Modulators, Yi-Chen Shuai Jan 2013

Transfer-Printed Photonic Crystal Nanomembrane Fano Resonance Filters And Modulators, Yi-Chen Shuai

Electrical Engineering Dissertations - Archive

This dissertation presents the research work on photonic crystal nanomembrane Fano resonance devices based on transfer printing techniques. Ultra-compact high quality (Q) factor optical filters have been design, fabricated, and characterized based on single-layer and coupled double-layer photonic crystal slabs (PCS). Optical filters have also been designed and investigated for potentially high speed spatial lighting modulations. Fano resonance membrane reflectors with operation wavelength bands cover from near-infrared to mid and far-infrared have also been fabricated based on both reaction ion-etching and magnetic field guided metal-assisted chemical etching processes.Based on crystalline semiconductor nanomembrane transfer printing technique, we designed and experimentally demonstrated …

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Cmos Analog Correlator Based Glucose Sensor Readout Circuit, Varun K. Shenoy Jan 2013

Cmos Analog Correlator Based Glucose Sensor Readout Circuit, Varun K. Shenoy

Electrical Engineering Dissertations - Archive

Recent investigations show research and development of alternative methods of glucose sensing using electrochemical biosensors to help significantly reduce the difficulties associated with treating diabetes. The integration of microelectronic circuit technology with biosensors is generating greater research interest. The advantages of small size and less power consumption of integrated circuits (ICs) are helping with the realization of biosensors for improved performance. The major challenges involving designing of readout ICs for the electrochemical biosensors are accuracy and range. In this research work, an analog correlator based readout circuit for amperometric glucose electrochemical biosensors is designed and implemented. It is designed to …

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A Numerical Study Of Incompressible Fluid Flow Over A Forward Facing Step At Various Grades, Peter Andrew Martinez Jan 2013

A Numerical Study Of Incompressible Fluid Flow Over A Forward Facing Step At Various Grades, Peter Andrew Martinez

Mechanical and Aerospace Engineering Theses - Archive

The study of the effect of natural forces on hydraulic structures is of great concern for the accurate prediction of when a design could be at risk of failure. In recent times the use of the shallow water equations to predict the behavior of the free surface for flow over a step has proven inaccurate because only a hydrostatic pressure distribution is considered. One of the phenomena that will not be accounted for with the shallow water equations in such a setup is the formulation of undular bore type waves on the surface. In order for a more accurate representation …

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Design, Fabrication And Test Of Surface Tension-Driven Microboats And Thermally Oscillatory Bubble-Propelled Microsubmarines, Lei Qiao Jan 2013

Design, Fabrication And Test Of Surface Tension-Driven Microboats And Thermally Oscillatory Bubble-Propelled Microsubmarines, Lei Qiao

Mechanical and Aerospace Engineering Dissertations - Archive

In this work, we develop microboats and microsubmarines, which are capable of moving on and under water, respectively. The microboat is propelled due to the difference between surface tensions around stern and bow. This difference is generated by releasing a liquid with lower surface tension than water from the stern. We explore both horizontal and vertical motions of the microboats through a combination of experimental and theoretical investigations. It has a length of 8 mm and weight of 20 mg with the highest speed of 25 cm/s and travel distance of 85 cm. Moreover, we design, fabricate and test microboats …

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Effect Of Suction On Dynamic Properties Of Unsaturated Soils At Mid- To High-Shear Strain Amplitudes, Alejandro Hernan Pino Bravo Jan 2013

Effect Of Suction On Dynamic Properties Of Unsaturated Soils At Mid- To High-Shear Strain Amplitudes, Alejandro Hernan Pino Bravo

Civil Engineering Theses - Archive

This paper presents the results from an experimental study that has been designed to assess the effect of the suction and net mean stress on the dynamic properties of poorly graded sand with silt subjected to small- to mid-shear strains. The practical implication of this study includes determining the effect on soil stiffness properties of increased matric suction (transpiration of water) at different net mean stresses (or depths) in the field. The engineering analysis of earth structures subjected to static and non-static loading under unsaturated conditions requires knowing the relevant parameters of the soil, such as shear wave velocity, shear …

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Lrfd Pullout Resistance Factor Calibration For Soil Nails Incorporating Survival Analysis And Plaxis 2d, Brett Devries Jan 2013

Lrfd Pullout Resistance Factor Calibration For Soil Nails Incorporating Survival Analysis And Plaxis 2d, Brett Devries

Civil Engineering Theses - Archive

The use of soil nail walls (SNWs) in the United States has increased since their introduction in the mid-1970's, to where currently the analysis, design and construction are commonly performed (Lazarte, 2011). These SNW designs were mostly based on ASD methods and LRFD-based methodologies were lacking until the 1998 FHWA manual on SNW design (Byrne, Cotton, Porterfield, Wolschlag and Ueblacker, 1998), which provided uncalibrated resistance factors developed from ASD safety factors. As a result, little improvement was made toward a more efficient design, until fully calibrated LRFD pullout resistance factors were provided in the NCHRP Report 701 (Lazarte, 2011). These …

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Enhancing Selective Decomposition Of Ibuprofen Onto Porous Tio₂ Nanoparticles, Abolfazl Zakersalehi Jan 2013

Enhancing Selective Decomposition Of Ibuprofen Onto Porous Tio₂ Nanoparticles, Abolfazl Zakersalehi

Civil Engineering Theses - Archive

Advanced oxidation technologies have gained tremendous attention for water treatment purposes after demonstration of insufficient efficiency of conventional systems for removal of many emerging chemicals of concern. Among AOTs, a TiO2-UV system is one of the most promising approaches due to its green properties and its effectiveness in generation of extremely oxidizing species such as hydroxyl radicals. However it has been demonstrated that non-selectivity of HRs in decomposition of organic compounds results in parallel decomposing of naturally abundant organic matter (NOM) along with toxic target contaminant, which significantly decreases the decomposition rate of target contaminants. Despite a great amount of …

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Investigations To Develop Field Stabilization Methods To Mitigate Surficial Slope Failures, Minh Le Jan 2013

Investigations To Develop Field Stabilization Methods To Mitigate Surficial Slope Failures, Minh Le

Civil Engineering Dissertations - Archive

Surficial slope failures induced by rainfall have been studied for many years. Current research supported by The United States Army Corps of Engineers (USACE) is undertaken at the University of Texas at Arlington on two sites, Joe Pool Dam and Grapevine Dam located in the Fort Worth district. The objective of the project is to find the best stabilization method to mitigate those failures. A testing area of 5 sections (one control and four treated) was established on each site with used admixtures of 20% compost, 4% lime with 0.30% polypropylene fibers, 8% lime with 0.15% polypropylene fibers, and 8% …

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Hydraulic Performance Evaluation Of Different Recirculation Systems For Elr / Bioreactor Landfills, Shahed R. Manzur Jan 2013

Hydraulic Performance Evaluation Of Different Recirculation Systems For Elr / Bioreactor Landfills, Shahed R. Manzur

Civil Engineering Dissertations - Archive

The major aspect of bioreactor landfill is the addition of liquid and recirculation of collected leachate back into the waste mass through the subsurface Leachate Recirculation System (LRS). The leachate recirculation system consists of the perforated recirculation pipes placed inside horizontal trenches and the permeable beds with different orientation. The application of high permeability material (shredded tire chips, broken glass, pea gravel) in landfills is an emerging technology to distribute the moisture over a wider area in a shorter period of time. Horizontal or vertical perforated pipes are installed in bioreactor landfills as LRS with an expectation of uniform moisture …

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Large Diameter Steel Pipe Field Test Using Controlled Low Strength Material And Staged Construction Modeling Using 3-D Nonlinear Finite Element Analysis, Franciele Bellaver Jan 2013

Large Diameter Steel Pipe Field Test Using Controlled Low Strength Material And Staged Construction Modeling Using 3-D Nonlinear Finite Element Analysis, Franciele Bellaver

Civil Engineering Theses - Archive

Using finite element methods and field tests, an extensive study on selected steel pipes is devised for the Integrated Pipeline Project in Dallas-Fort Worth, Texas. The project integrates Tarrant Regional Water District (TRWD) existing pipelines to the Dallas system along 150 miles. Field test of buried pipes, monitoring the pipe in different trench conditions is extremely valuable in predicting the displacement of the pipe during construction stages and during its lifetime. The field instrumentation monitors the circular displacements and strains of a buried steel pipe with an outside diameter (O.D.) of 84 in. and 0.375 in. thickness in three different …

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Determination Of Safe Roadway Buffer Width To Protect Human Health From No2 Exposure: A Case Study For Grand Prairie, Tx, Hetal Bhatt, Melanie L. Sattler, Stephen P. Mattingly Jan 2013

Determination Of Safe Roadway Buffer Width To Protect Human Health From No2 Exposure: A Case Study For Grand Prairie, Tx, Hetal Bhatt, Melanie L. Sattler, Stephen P. Mattingly

Civil Engineering Faculty Publications - Archive

No abstract provided.

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Sustainable Slope Stabilization Using Recycled Plastic Pin In Texas, Mohammad Sadik Khan Jan 2013

Sustainable Slope Stabilization Using Recycled Plastic Pin In Texas, Mohammad Sadik Khan

Civil Engineering Dissertations - Archive

Shallow slope failures are predominant in the North Texas area and pose significant maintenance problems for the Texas Department of Transportation (TxDOT). As a cost effective alternative, the Recycled Plastic Pin (RPP) can be utilized to stabilize the shallow slope failure. RPP are fabricated from recycled plastics and waste materials (i.e. polymers, sawdust, and fly ash). It is a lightweight material and less susceptible to chemical and biological degradation than alternative reinforcing element. RPPs are driven into the slope face, which provide additional resistance along the slip surface and increase the factor of safety. The current study summarized the remediation …

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Global Optimization Of Nonconvex Piecewise Linear Regression Splines, Nadia Maria Martinez Cepeda Jan 2013

Global Optimization Of Nonconvex Piecewise Linear Regression Splines, Nadia Maria Martinez Cepeda

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Global optimization has been applied to a wide variety of science and engineering design problems. Although numerous global optimization techniques have been developed and studied for decades, when used for complex systems such as the design of an aircraft or an automobile, the results are impractical or not completely satisfactory. One of the main drawbacks is the computational CPU time required to solve these problems. The majority of design problems require a significant number of experiments or simulations in order to find a globally best solution; however a single simulation can take between seconds and days to finish. One way …

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