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Articles 3031 - 3060 of 3180

Full-Text Articles in Engineering

Hourly Weather Forecast Analysis, Sothaya Rasmidatta Aug 2006

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 Aug 2006

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 Aug 2006

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 Aug 2006

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 Aug 2006

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 …


General Response Of Kneading-Compacted Unsaturated Silty Sand Under Drained And Undrained True Triaxial Testing, Sangchul Pyo Aug 2006

General Response Of Kneading-Compacted Unsaturated Silty Sand Under Drained And Undrained True Triaxial Testing, Sangchul Pyo

Civil Engineering Theses - Archive

A comprehensive series of 36 drained and 36 undrained true triaxial tests was accomplished to investigate the stress-strain-strength behaviour of kneading-compacted unsaturated silty sand (SP-SM) under multi-axial stress states. Test specimens were prepared at three different initial moist contents (6, 8, 10%) to achieve different compaction-induced suction conditions prior to testing. All samples were then subjected to either a drained or undrained multi-axial stress paths, including conventional triaxial compression (CTC), triaxial compression (TC), triaxial extension (TE), or simple shear (SS) stress path. Initial compaction-induced matric suction was assessed via the SWCC of test soil. The experimental program focuses on soil …


Photocatalytic Degradation Of Vocs, Toxics And Odors From Air Emissions Of Wastewater Treatment Plants And Municipal Solid Waste Landfills, Mita Suresh Upadhyay Aug 2006

Photocatalytic Degradation Of Vocs, Toxics And Odors From Air Emissions Of Wastewater Treatment Plants And Municipal Solid Waste Landfills, Mita Suresh Upadhyay

Civil Engineering Theses - Archive

The 1990 Clean Air Act Amendments (CAAA) require more stringent controls of sources of volatile organic compounds (VOCs) and hazardous air pollutants (HAPs). Air quality managers at the state level are responsible for developing State Implementation Plans (SIPs) to improve regional air quality. Both wastewater treatment and landfills facilities are sources of VOCs, HAPs and odors. This research examines the effectiveness of photocatalytic oxidation (PCO) in treating emissions from wastewater and landfill facilities. PCO rate constants of compounds such as methane, o-xylene, m-xylene, p-xylene and carbonyl sulfide are determined over titanium dioxide (TiO2) catalyst in a continuous mixed-batch reactor. The …


Evaluation Of Resilient Modulus Of Cement And Cement-Fiber Treated Reclaimed Asphalt Pavement (Rap) Aggregates, Ajay Potturi Aug 2006

Evaluation Of Resilient Modulus Of Cement And Cement-Fiber Treated Reclaimed Asphalt Pavement (Rap) Aggregates, Ajay Potturi

Civil Engineering Theses - Archive

Natural aggregates derived from a variety of source rocks have been used as a road base material. But the extraction of natural aggregates resources is increasingly being constrained by urbanization, increased costs and environmental concerns. Thus, increased amounts of reclaimed materials are being used to supplement natural aggregates in road construction. The 1993 EPA report mentioned that approximately 73 million tons of asphalt pavement material was recycled annually, which amounts to about 80% of the asphalt removed from pavements each year. The use of Reclaimed Asphalt Pavement (RAP) materials in road construction reduces both the amount of construction debris disposed …


Recirculating Loop Testbed For All Optical 2r Regeneration, Pallavi Govind Patki Aug 2006

Recirculating Loop Testbed For All Optical 2r Regeneration, Pallavi Govind Patki

Electrical Engineering Theses - Archive

This Master's thesis deals with building a recirculating loop testbed intended for proof-of-principle demonstration of multichannel all-optical 2R regenerator proposed in [1]. The proposed multichannel 2R regeneration scheme uses multiple highly-nonlinear-fiber (HNLF) sections separated by dispersion-compensating periodic-group-delay devices (PGDDs). The high cost and limited availability of these devices restrict us to working with just one PGDD, instead of 16 required by the scheme. Thus, for the proof-of-principle demonstration of the regenerator we have to put a single PGDD and a piece of HNLF into a recirculating loop through which light will circulate for required number of times. In this thesis, …


Optimization Models For Leishmaniasis Control: A Case For Bihar, India, Kaushik Gorahava Aug 2006

Optimization Models For Leishmaniasis Control: A Case For Bihar, India, Kaushik Gorahava

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Leishmaniasis, is a family of infectious diseases, which mostly affects poor and developing countries. The highest prevalence and mortality rate of Visceral Leishmaniasis (VL) the world over occurs in Bihar state of India. Many disease control methods are available; however, procedures aimed at reducing sandfly population by spraying insecticide have been the most effective for controlling VL in Bihar. In this dissertation, optimization models for the control of Leishmaniasis are developed and analyzed. Novel optimization models are built and analyzed to identify the optimal amount of insecticide allocated for controlling the spread of VL in Bihar. Since the vector (disease …


Rf Mems And Integrated Manufacturing For Miniaturized Millimeter-Wave Systems, Ying Cai Aug 2006

Rf Mems And Integrated Manufacturing For Miniaturized Millimeter-Wave Systems, Ying Cai

Electrical Engineering Dissertations - Archive

Recently millimeter-wave systems have attracted more attentions in applications owing to their short wavelengths, high resolutions, broad bandwidths and high environmental tolerance. However, the great challenges of high fabrication and assembly costs, bulky volume, and heavy weight of millimeter-wave systems call for new integrated manufacturing techniques and novel architectures. The micro hot embossing technique integrated with other microfabrication techniques could address these challenges. In this dissertation, the micro plastic hot embossing technique was presented for the fabrication of miniaturized millimeter-wave systems. The micro hot embossing on plastic materials demonstrated its advantages on significant costs, volume, and weight reduction, while maintaining …


Electromagnetic Wave Scattering From Vegetation, Xiaoyan Huang Aug 2006

Electromagnetic Wave Scattering From Vegetation, Xiaoyan Huang

Electrical Engineering Dissertations - Archive

This dissertation contains the theoretical study of microwave scattering from vegetated media and the development of microwave scattering models with applications to these media. A vegetation canopy may consist of deciduous or coniferous leaves, branches, and trunks with certain size and orientation distributions. The formulation of the scattering model for each element of the canopy is carried out and its scatter patterns versus its size and orientation for like and cross polarizations are computed and presented. In particular, an extension is made where vegetation with a compound-leaf pattern is considered. For this type of vegetation, several leaves that form a …


Device Level Vacuum Packaged Microbolometers On Flexible Substrates, Aamer Mahmood Aug 2006

Device Level Vacuum Packaged Microbolometers On Flexible Substrates, Aamer Mahmood

Electrical Engineering Dissertations - Archive

Micromachined microbolometers on flexible substrate have been fabricated and characterized. Liquid polyimide PI5878G made by HD Microsystems has been used to form the flexible substrate. Semiconducting Yttrium-Barium-Copper-Oxide (commonly referred to as YBCO) is the temperature sensitive material. These detectors are supported by thin micromachined layers of silicon nitride on flexible polyimide PI5878G. The devices were characterized for temperature dependent resistance (R(T)), the temperature coefficient of resistance (TCR, ), responsivity , detectivity (D*) and thermal conductance (Gth). A typical device had a resistance of 3.76 MI and a TCR of -2.63 %/K at 301 K. The measured thermal conductance was W/K. …


Nonlinear Control Of Microelectromechanical Systems (Mems) Devices, Kwadwo Osei Owusu Aug 2006

Nonlinear Control Of Microelectromechanical Systems (Mems) Devices, Kwadwo Osei Owusu

Electrical Engineering Theses - Archive

Different actuation principles have been developed for MEMS but electrostatic actuators are the most common. A significant drawback in the use of electrostatic actuators for some applications is their nonlinear voltage to position characteristics. Analog operation of these devices requires the use of feedback to stabilize and linearize them. Controlling and optimizing the operation of electrostatic controllers using feedback requires the establishment of the complete and accurate dynamical model of the device. In this thesis, we show how an optical switch driven by a MEMS electrostatic comb drive is controlled to guarantee its performance, stability and reliability for use in …


3d Interconnects For Die And Wafer Stacks, Rachita Dewan Aug 2006

3d Interconnects For Die And Wafer Stacks, Rachita Dewan

Electrical Engineering Theses - Archive

3D integration results from the ever demanding trend towards smaller and lower-profile, lighter and lower cost packaged devices requires further package miniaturization. With the present System-on-chip (SOC) technology reaching its limitation in terms of functionality and cost, effort are being concentrated on exploring the third dimension, i.e. 3D integration. It provides a volumetric packaging solution for higher integration and performance and results in size and weight reduction. Approaches to achieve 3D integration are die and wafer stacking. A key technology to realize the potential of stacking is implementation of vertical electrical interconnects between die and wafer stacks. This thesis discusses …


The Design And Analysis Of Optical Scanners For Optical Coherence Tomography, Naresh Dhaubanjar Aug 2006

The Design And Analysis Of Optical Scanners For Optical Coherence Tomography, Naresh Dhaubanjar

Electrical Engineering Theses - Archive

A miniature fiber optic scanner capable of two-dimensional scanning for medical imaging is designed and developed. The scanner is actuated externally using an electromagnet. Nickel gel, a soft ferromagnetic material, is coated on the optical fiber. The performance of the scanner is characterized. Finite element analysis is performed to validate the theoretical and experimental results. A design and analysis of a cantilever type electrostatic zipping actuator and a bidirectional vertical thermal actuator are presented. The actuation principle, lumped modeling analysis, experimental results, and finite element analysis of both actuators are presented. The actuators are characterized statically and dynamically using the …


Modeling And Performance Evaluation Of A Power Electronic-Based Controlled Fuel Cell System, Yashar Ehsan Kenarangui Aug 2006

Modeling And Performance Evaluation Of A Power Electronic-Based Controlled Fuel Cell System, Yashar Ehsan Kenarangui

Electrical Engineering Theses - Archive

In fuel cell applications, design of an appropriate controller and selection of an Ultra-Capacitor require a suitable model of fuel-cell-systems that can adequately represent the significant characteristics of the system. Such a model, using lumped circuit elements, was developed in this thesis via a simple method without requiring fuel cell design parameters. To validate the model, simulation results from the model were compared against the results from experimental setups and satisfactory results were obtained. Later, this model was used in order to design a controller that meets the control objectives, namely, regulation of output voltage and attenuation of load current …


Experimental Investigations On Small-Strain Stiffness Properties Of Partially Saturated Soils Via Resonant Column And Bender Element Testing, Phayak Takkabutr Aug 2006

Experimental Investigations On Small-Strain Stiffness Properties Of Partially Saturated Soils Via Resonant Column And Bender Element Testing, Phayak Takkabutr

Civil Engineering Dissertations - Archive

A comprehensive series of resonant column (ASTM D 2325-68), bender element (ASTM C 778), pressure plate (ASTM D 4015-92), and filter paper (ASTM D 5298) tests were conducted on compacted specimens of poorly graded sand (SP) and high plasticity clay (CH) in order to assess the influence of key environmental factors, namely compaction-induced matric suction and Ko stress state, on small-strain stiffness properties of partially saturated soils. Compaction-induced matric suction in all test specimens was estimated via soil-water characteristic curves (SWCC) for each type of soil. The research work was accomplished in six broad stages. During Stage I, a modified …


Mode Choice Models For Long Distance Travel In Usa, Isaradatta Rasmidatta Aug 2006

Mode Choice Models For Long Distance Travel In Usa, Isaradatta Rasmidatta

Civil Engineering Dissertations - Archive

The influences of technology and economic development on human activity are increasingly taking place on larger spatial scales. As a consequence, complementary interactions between urban regions are getting stronger, which causes urban regions to change. In order to stimulate the integration between regions and states level, policy makers need increased knowledge of the factors that influence long distance travel. From an environmental perspective, long distance trips can be very important because most of the trips are made in personal vehicles or airplanes that affect emissions and fuel consumption. Mode choice alternatives for long distance travel include: personal vehicle, air, and …


Statistical Modeling Approach To Airline Revenue Management With Overbooking, Sheela Siddappa Aug 2006

Statistical Modeling Approach To Airline Revenue Management With Overbooking, Sheela Siddappa

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

A Revenue Management (RM) method in the airline industry plays a very important role in maximizing revenue under various uncertainty issues, like customer demand, the number of seats to be maintained in inventory, the number of seats to be overbooked, etc. In this dissertation, a Markov decision process (MDP) based approach using statistical modeling is presented. Prior versions of this statistical modeling approach have employed remaining seat capacity ranges from zero to the capacity of the aircraft. In reality, actual remaining capacities are near capacity when the booking process begins and near zero when the flights depart. Thus, our modified …


Parameters Affecting Critical Heat Flux Of Nanofluids: Heater Size, Pressure Orientation And Anti-Freeze Addition, Madhav Rao Kashinath Aug 2006

Parameters Affecting Critical Heat Flux Of Nanofluids: Heater Size, Pressure Orientation And Anti-Freeze Addition, Madhav Rao Kashinath

Mechanical and Aerospace Engineering Theses - Archive

This research aims at investigating the effect, heater size, pressure, heater orientation and effect of anti-freeze addition on critical heat flux of nanofluids which have shown large potentials as coolants for high power generating uses. Nanofluids have shown about ~180 - 200% enhancement in the critical heat flux values. The effect of heater size employing three different sized heaters yielded about ~180% enhancement over pure water. The effect of pressure on critical heat flux investigated by testing nanofluids at three pressures showed ~240% increase in critical heat flux. Surface orientation effect on critical heat flux carried out for a 2 …


Development Of Three Block Thermal Compact Model And Verification Of Modified Linear Superposition Technique For Stacked Die, Suresh G. Nikalaje Aug 2006

Development Of Three Block Thermal Compact Model And Verification Of Modified Linear Superposition Technique For Stacked Die, Suresh G. Nikalaje

Mechanical and Aerospace Engineering Theses - Archive

Over the last few years an impressive amount of progress has been achieved in the field of compact modeling of chip packages. But available compact modeling methods could not address the issue of limitation on the mesh statistics which is major concern while modeling in FEM softwares with limited number of nodes and elements. It is not possible to attain convergence of solution for thermal simulation of detailed model with the constraint on the number of nodes and elements. In this thesis, a simple and straight forward three block (3B) compact modeling method is developed. 3B compact modeling method has …


Investigation Of Bamboo As Reinforcement In Concrete, Youngsi Jung Aug 2006

Investigation Of Bamboo As Reinforcement In Concrete, Youngsi Jung

Civil Engineering Theses - Archive

This study investigated the feasibility of using bamboo as a reinforcement alternative to steel in concrete structural members. The specifications studied were the bamboo's tensile strength and its pullout characteristics in concrete. Two types of bamboo, Solid and Moso, were used for tensile testing. The tensile test specimens were prepared with different lengths, 6 in (152 mm) and 12 in (304 mm), and different physical characteristics (with and without nodes). Tensile test specimens were tested to failure and their load deformation characteristics are reported. The failures of the test specimens were identified as: (1) node failure; (2) splitting failure; and …


Novel Preparation Of Polymeric Scaffolds For Tissue Engineering Using Phase Separation With Protein Microbubble Incorporation, Ashwin Nair Aug 2006

Novel Preparation Of Polymeric Scaffolds For Tissue Engineering Using Phase Separation With Protein Microbubble Incorporation, Ashwin Nair

Bioengineering Theses - Archive

Poly (lactic-co-glycolic acid) (PLGA) has been extensively used as a biodegradable and porous tissue scaffold due to their biocompatibility and degradability. Several techniques have been developed for the fabrication of polymeric scaffolds but they all have some limitation or the other which has in turn hampered the growth of cells seeded on them. Salt leached scaffolds have good porosity and large pores but poor mechanical strength and the problem of residual salt even after leaching. Similarly gas foaming scaffolds have shown large pores but poor interconnection with residual ammonium salts. Other methods like thermally induced phase separation and fiber bonding …


Use Of Near Infrared And Visible Spectroscopies To Determine Optical Properties Of Rat Nervous System, Harsha Radhakrishnan Aug 2006

Use Of Near Infrared And Visible Spectroscopies To Determine Optical Properties Of Rat Nervous System, Harsha Radhakrishnan

Bioengineering Theses - Archive

Changes to the anatomical or physiological structure of the neuronal circuitry are known to produce a change in the optical properties of the tissue under investigation. The goal of this thesis is to determine changes in the light scattering and hemoglobin oxygen saturation in three cases: (i) a normal spinal cord, (ii) demyelinated sciatic nerve, and (iii) spinal cord under neuronal activity induced by peripheral electrical stimulation. We hypothesize that (i) nerve demyelination or degeneration would result in a decrease in light scattering and hemoglobin oxygen saturation and (ii) peripheral electrical stimulation would show an increase in light scattering and …


Analysis Of Electromagnetic Field In A Switched Reluctance Machine From An Energy Conversion Perspective, Wei Jiang Jul 2006

Analysis Of Electromagnetic Field In A Switched Reluctance Machine From An Energy Conversion Perspective, Wei Jiang

Electrical Engineering Theses - Archive

With the recent advancement in power electronics and digital signal processors, switched reluctance machine (SRM) attracts more attention in high speed and harsh environment applications due to its rugged and robust structure. Despite considerable progress in the development of power electronics based control of the SRM, relatively small changes in the magnetic design has been observed. A physically insightful analysis of the electromechanical energy conversion process, origins and spatial distribution of electromagnetic field quantities at a microscopic level can shed light on the process of SRM design, which in turn could create new opportunities for substantial improvement of SRM performance …


Crashworthiness Design Optimization Using Surrogate Models, Cheng-Ho Tho Jul 2006

Crashworthiness Design Optimization Using Surrogate Models, Cheng-Ho Tho

Mechanical and Aerospace Engineering Dissertations - Archive

Despite the advances in computer technology, the enormous computational cost associated with the large-scale and complex nonlinear crashworthiness simulations renders it to be impractical to rely exclusively on computer simulations for crashworthiness design optimization. A preferable strategy is to employ the computational efficient surrogate model in lieu of the expensive simulations to facilitate the optimization process and design concept exploration. An added advantage of the surrogate models is that they tends to eliminate the high-frequency numerical noise which may hinder the performance of the direct gradient-based optimization technique by constructing smooth crash responses in the crashworthiness analysis. Even thought the …


Nonlinear Finite Element-Based Investigation Of The Effect Of Bedding Thickness On Underground Pipe, Anupong Kararam Jul 2006

Nonlinear Finite Element-Based Investigation Of The Effect Of Bedding Thickness On Underground Pipe, Anupong Kararam

Civil Engineering Theses - Archive

The pipe-soil interaction is studied by using the finite element software, ABAQUS/CAE Version 6.5-1 as a symmetric model of embankment installation to study the effect of bedding property and thickness on pipe-soil interaction with increase in the height of fill. A three-dimensional finite element model (FEM) of the concrete pipe and surrounding soil is developed. The FEM is capable of simulating material, geometric, and contact nonlinearities which employs a nonlinear incremental solution algorithm. Several different element types and mesh size were tested to obtain the optimum converged mesh. These elements were eight-noded linear brick (C3D8R) and six-noded linear triangular prism …


Web-Based Real-Time Monitoring System To Enhance The Participation Of An Industrial Power System In A Restructured Utility Industry, Shun-Hsien Huang Jul 2006

Web-Based Real-Time Monitoring System To Enhance The Participation Of An Industrial Power System In A Restructured Utility Industry, Shun-Hsien Huang

Electrical Engineering Dissertations - Archive

The opening of the Electric Reliability Council of Texas (ERCOT) grid to wholesale competition began in 1996 that initiated the first stage of deregulation in Texas. In order to relieve generation and transmission constraints, load reduction is considered as a form of available energy and spinning reserve. Afterward, power system becomes more dynamic and creates more opportunities for both electricity suppliers and consumers. Currently, both power supplier and demand consumer can participate in the energy and ancillary services (AS) markets to bid/offer for their energy, capacity, and demand in the ERCOT markets. In order to act as an effective market …


An Emission Model For Lunar Regolith Surfaces Based On Matrix Doubling Method, Darshan Shrestha Jul 2006

An Emission Model For Lunar Regolith Surfaces Based On Matrix Doubling Method, Darshan Shrestha

Electrical Engineering Theses - Archive

An emission model based on Matrix Doubling Method is implemented for the calculation of emission signatures from the lunar regolith surfaces. The matrix doubling method is used to solve the radiative transfer equations which encompass the volume and surface scattering properties of the medium. The layer and surface are characterized by their corresponding phase matrices which contain adequate information on how the amplitude, phase and polarization of the incident Stokes vector change on being incident in that medium. Emissivity signatures are calculated by solving the transfer equations using matrix doubling method and taking these phase matrices as "boundary conditions". The …