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Articles 2401 - 2430 of 2904

Full-Text Articles in Engineering

Material Flow Control In A Sequence Dependent Job Shop Via Order Release And Dispatching Mechanisms, Francesco Gentile Aug 2008

Material Flow Control In A Sequence Dependent Job Shop Via Order Release And Dispatching Mechanisms, Francesco Gentile

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Material flow control on the shop floor involves the release and dispatching of orders to meet customer due dates, while minimizing operating costs. The early release of orders to the shop floor does not necessarily ensure delivery performance and often results in unnecessary shop congestion and excessive cost. Thus, determining when order release should occur and how dispatching should be accomplished is critical to the success of a manufacturing organization. Although there has been a significant amount of research in the material flow control literature regarding the job shop environment, there exists a significant void with respect to order release …


Independent Study On Infinite Graph Theory, Martin Zimmermann Jul 2008

Independent Study On Infinite Graph Theory, Martin Zimmermann

Technical Reports

In this paper we will prove some results about infinite graphs. We show that for every linear order there is a graph with a distinguished vertex such that the edges adjacent to that vertex have the given order in any plane drawing. The other results are concerned with connectivity. We prove a generalization of a characterization of 2-­connected graphs and prove that k-­connectedness does not imply the existence of finite k­connected subgraphs for k > 2.


Comparison Of Cooling Performance Of Overhead And Underfloor Supply With Rear Door Heat Exchanger In High Density Data Center Clusters, Ravi K. Udakeri Jul 2008

Comparison Of Cooling Performance Of Overhead And Underfloor Supply With Rear Door Heat Exchanger In High Density Data Center Clusters, Ravi K. Udakeri

Mechanical and Aerospace Engineering Theses - Archive

The power trend for server systems continues to grow thereby making thermal management of Data centers a very challenging task. Although various configurations exist, the raised floor plenum with Computer Room Air Conditioners (CRACs) providing cold air is a popular operating strategy. In prior work, numerous data center layouts employing raised floor plenum and the impact of design parameters such as plenum depth, ceiling height, cold isle location, tile openings and others on thermal performance of data center was presented. The air cooling of data center however, may not address the situation where more energy is expended in cooling infrastructure …


Thermo-Mechanical Solutions In Electronic Packaging: Component To System Level, Aalok Trivedi Jul 2008

Thermo-Mechanical Solutions In Electronic Packaging: Component To System Level, Aalok Trivedi

Mechanical and Aerospace Engineering Theses - Archive

Since the advent of the transistor and integrated circuit, the performance of electronic equipment has increased significantly while footprint of systems at all levels continues to decrease. Recently, the number of transistors on a high end microprocessor has exceeded a billion. All of the above has necessitated considerable improvement in cooling technology and associated reliability. In this era of high heat fluxes, air cooling still remains the primary cooling solution mainly due to its cost and ease of installation and operation. The primary goal of a good thermal design is to ensure that the chip can function at its rated …


Structural Optimization Using Matlab Partial Differential Equation Toolbox And Radial Basis Function Based Response Surface Model, Faisal Tanveer Mosharrof Jul 2008

Structural Optimization Using Matlab Partial Differential Equation Toolbox And Radial Basis Function Based Response Surface Model, Faisal Tanveer Mosharrof

Mechanical and Aerospace Engineering Theses - Archive

As a decision making tool, optimization has become an inseparable part of the modern design process. However, in spite of the advances in computer capacity and speed, the computational time for some complex problems is too high to use conventional solution approach. In order to reduce the computational effort and the cost associated with such type of problems, approximation methods such as response surface methodology (RSM) along with design of experiments (DOE) are used in engineering design optimization. The main idea involves replacing the expensive simulation model during the design and optimization process with a simplified mathematical approximation of the …


Design Of Analog Correlator For 22-29ghz Uwb Vehicular Radar Systems In Ibm 90nm Cmos Process, Niranjan Karandikar Jul 2008

Design Of Analog Correlator For 22-29ghz Uwb Vehicular Radar Systems In Ibm 90nm Cmos Process, Niranjan Karandikar

Electrical Engineering Theses - Archive

In this thesis analog correlator is designed for UWB vehicular radar system. Operating frequency of the correlator is 22-29GHz. IBM 90nm CMOS process is used for the design, Simulation are done in CADENCE Spectre and SpectreRF. UWB signal of 22-29GHz is generated in ADS. Gaussian mono-pulse is shaped with band-pass filter to meet FCC mask. Simulations are done by using this signal. Typical receiver of UWB system consists of LNA, analog correlator and ADC. Analog correlator is the matched filter which is a part of receiver. It is used to detect the incoming RF signal by maximizing signal to noise …


Simulation Of Tetrahedral Mesh Based Organ Deformation Using Parameter Optimized Spring Constants, Koyel Mukherjee Jul 2008

Simulation Of Tetrahedral Mesh Based Organ Deformation Using Parameter Optimized Spring Constants, Koyel Mukherjee

Electrical Engineering Theses - Archive

Virtual reality based surgical simulators are becoming increasingly popular for training doctors on minimally invasive surgery. For these simulators, it is necessary to generate 3D organ models and create virtual environments depicting visually realistic deformation response by tissues and organs to manipulations by surgical tools. For creating a 3D model, several different approaches have been used by the computer graphics community, among which polygonal/polyhedral meshes have gained popularity for real time virtual reality applications. This work investigates two problems in 3D organ modeling for virtual reality simulators. Firstly, we consider the use of unstructured 3D meshes for generation of organ …


Implementation And Evaluation Of Residual Color Transform For 4:4:4 Rgb Lossless Coding, Pooja Vasant Agawane Jul 2008

Implementation And Evaluation Of Residual Color Transform For 4:4:4 Rgb Lossless Coding, Pooja Vasant Agawane

Electrical Engineering Theses - Archive

The 4:4:4 video sampling format promises an excellent quality video. It is gaining a lot of attention due to its significance in the professional applications of multimedia processing. The use of the RGB color space for video processing is attracting, both, the industry and the academia. Extensive research is being undertaken to achieve better compression efficiency and high coding gain in the RGB (red, green, blue) color space. In contrast to typical consumer applications, high quality video is demanded in areas such as professional digital video recording, video post production and digital cinema. These latter applications demand all three color …


Diagnosis And Prognosis Of Electrical And Mechanical Faults Using Wireless Sensor Networks And A Two-Stage Neural Network Classifier, Akarsha Ramani Jul 2008

Diagnosis And Prognosis Of Electrical And Mechanical Faults Using Wireless Sensor Networks And A Two-Stage Neural Network Classifier, Akarsha Ramani

Electrical Engineering Theses - Archive

Diagnosis and isolation of electrical and mechanical problems in induction motors has always been a very challenging task. Some of the common problems in induction motors are: bearing, stator winding, and rotor bar failures. This thesis has three phases: The first one pertains to development of low-cost test-beds for simulating bearing faults and short circuit stator winding faults in a motor. Bearing fault is due to the failure of any of the components of the bearing and the stator winding fault is due to the failure of insulation between the windings. Bearing faults can be identified from the motor vibration …


Theoretical And Experimental Study Of Wide-Band Quasi-Planar Conical Antennas, Tsungyin Wu Jul 2008

Theoretical And Experimental Study Of Wide-Band Quasi-Planar Conical Antennas, Tsungyin Wu

Electrical Engineering Theses - Archive

Conical antennas are widely used in many applications because of their broad input impedance bandwidth and omni-directional radiation pattern. However, conical antennas usually have three-dimensional structures and are, hence, relatively difficult to fabricate and integrate. In this thesis, a quasi-planar conical antenna is proposed, where the simulation and measurement results indicate that dielectric loading could mechanically stabilize the antenna while keeping the input impedance invariant within a broad band. Also, the proposed antenna keeps the original wide-band and omni-directional properties. Specifically, a few configurations of the quasi-planar conical antenna are simulated, fabricated, and tested. The simulation and measurement results show …


Biodegradable Fluorescent Polymers, Santosh Gautam Jul 2008

Biodegradable Fluorescent Polymers, Santosh Gautam

Bioengineering Theses - Archive

Most of the works done on fluorescent polymers are focused on their potential applications in lighting industries. Much less interest has been paid for their potential application in the field of biology and biomedical engineering. Although multiple biological uses of green fluorescent proteins (GFPs) have been addressed by different groups, their potential for biomedical applications is hampered by their tendency to photobleach rapidly and their short fluorescence lifetime. Quantum dots have emerged as a potential substitute for those applications, but their cytotoxicity and lack of biodegradability restrict their use in a biological system. An ideal fluorescent material that could be …


Decision And Control In Distributed Cooperative Systems, Prasanna Mohan Ballal Jul 2008

Decision And Control In Distributed Cooperative Systems, Prasanna Mohan Ballal

Electrical Engineering Dissertations - Archive

This dissertation presents novel matrix-based approaches for decision and control in distributed cooperative systems such as wireless sensor networks. A novel matrix-based Discrete Event Controller has been implemented for task planning and resource dispatching in a network consisting of stationary ground sensors and mobile agents also known in the literature as mobile wireless sensor networks. The use of shared resources in such systems can sometimes cause a phenomenon called system deadlock, where all the processes in the system come to a standstill. This work presents a new matrix-based algorithm that has been implemented for deadlock avoidance in a system with …


Hardware Platform For Research In Helicopter Uav Control, Petru Emanuel Stingu Jul 2008

Hardware Platform For Research In Helicopter Uav Control, Petru Emanuel Stingu

Electrical Engineering Theses - Archive

The topic discussed in this work addresses the current research being conducted at the Automation & Robotics Research Institute in the areas of UAV helicopter instrumentation targeted towards aerobatic flight control and heterogenous multi-vehicle cooperation. A modular electronic control system is designed which includes sensors communicating over a CAN bus and an on-board computer that runs a special real-time Linux kernel. The majority the electronics is developed by the author, including the electronic schematics, PCB design, component soldering and the supporting software. Commercially available modules are used for the radio transceivers or the on-board computer. The same control system is …


Novel Algorithms For Medium/Low-Voltage Arcing Faults In Switchgear & Motor Coils: From Concept To Realization, Mandhir Singh Sahni Jul 2008

Novel Algorithms For Medium/Low-Voltage Arcing Faults In Switchgear & Motor Coils: From Concept To Realization, Mandhir Singh Sahni

Electrical Engineering Dissertations - Archive

Switchgear arcing faults have been a primary cause for concern for the manufacturing industry and safety personnel alike. The deregulation of the power industry being in full swing and ever-growing competitiveness in the distribution sector calls for the transition from preventive to predictive maintenance. Switchgear forms an integral part of the distribution system in any power system set-up. Keeping in mind the switchgear arcing faults, the transition mentioned above applies most of all to the switchgear industry. Apart from the fact that it is the primary cause of serious injuries to electrical workers worldwide, switchgear arcing faults directly affect the …


Image Mirroring, Rotation And Interpolation In The Wavelet Domain, Theju Isabelle Jacob Jul 2008

Image Mirroring, Rotation And Interpolation In The Wavelet Domain, Theju Isabelle Jacob

Electrical Engineering Theses - Archive

JPEG2000, the international standard for still image compression, uses the wavelet transform. The filters used in JPEG2000 for transformation are the 9/7 Daubechies filters and the 5/3 Le Gall filters. At present, to achieve image mirroring or rotation for images, one has to convert them back to spatial domain and proceed. This thesis presents methods by which it can be implemented in the wavelet domain, without extra computational complexity. To do so, one manipulates the transform domain coefficients so that the condition of perfect reconstruction still holds true. The thesis also discusses a method to achieve image interpolation, which would …


Performance Analysis And Effect Of Multi-User Interference For Ultra Wideband Communications, Mukta Athavale Jul 2008

Performance Analysis And Effect Of Multi-User Interference For Ultra Wideband Communications, Mukta Athavale

Electrical Engineering Theses - Archive

Ultra-Wideband (UWB) is an upcoming technology for short-range high data rate applications like Wireless Personal Area Networks or medium/long-range low data rate applications like sensor networks. UWB has many captivating characteristics such as very short duration pulses (order of nanoseconds), multipath channel, large instantaneous bandwidth and time hopping pulse trains resulting in coexistence with the existing narrow band users. The Ultra Wideband communication systems employ the technique of Impulse radio of transmitting short duration pulses which result in extremely wide bandwidth and many performance benefits. Since UWB systems operate in dense multipath environments, RAKE receiver is the optimum choice for …


Design Evaluation Of A Low-Tension Cable Guardrail End Terminal System, Cody S. Stolle, Karla A. Polivka, Ronald K. Faller, John R. Rohde, Dean L. Sicking, Rebecca A. Hitz, Kirk J. Molacek, John D. Reid Jul 2008

Design Evaluation Of A Low-Tension Cable Guardrail End Terminal System, Cody S. Stolle, Karla A. Polivka, Ronald K. Faller, John R. Rohde, Dean L. Sicking, Rebecca A. Hitz, Kirk J. Molacek, John D. Reid

Nebraska Department of Transportation: Research Reports

No abstract provided.


Generation Of Monthly Precipitation Under Limited Data And Climate Change: An Example From The Upper Blue Nile River Basin, U. Kim, Jagath J. Kaluarachchi, V. Smakhtin Jul 2008

Generation Of Monthly Precipitation Under Limited Data And Climate Change: An Example From The Upper Blue Nile River Basin, U. Kim, Jagath J. Kaluarachchi, V. Smakhtin

Civil and Environmental Engineering Faculty Publications

This work develops a methodology to project the future precipitation in large river basins under limited data and climate change while preserving the historical temporal and spatial characteristics. The computationally simple and reliable conditional generation method (CGM) is presented and applied to generate reliable monthly precipitation data in the upper Blue Nile River Basin of Ethiopia where rain-fed agriculture is prevalent. The results showed that the temporal analysis with the CGM performs better to reproduce the historical long-term characteristics than other methods, and the spatial analysis with the CGM reproduced the historical spatial structure accurately. A 100-year time series analysis …


Magnetic Drug Targeting: Development Of A Novel Drug Delivery System For Prostate Cancer Therapy, Maham Rahimi Jun 2008

Magnetic Drug Targeting: Development Of A Novel Drug Delivery System For Prostate Cancer Therapy, Maham Rahimi

Bioengineering Dissertations - Archive

Magnetic nanoparticles (MNPs) have been attracting a great amount of attention because of their numerous applications including contrast agents in magnetic resonance imaging (MRI), magnetic targeted drug carriers, and hyperthermia treatments for cancer. However, complications, including aggregation of MNPs, have limited their use in drug delivery applications. To overcome these limitations, several methods have been developed to coat magnetic particles. One method includes coating them with polymers to produce polymer/MNPs for increasing the MNP dispersion and stability. This method also increases the efficiency of loading and releasing drugs to specific locations for the treatment of various diseases including prostate cancer. …


Particle Composition And Size Distributions In And Around A Deep Pit Swine Operation, Randy S. Martin, P. J. Silva, Kori D. Moore, M. Erupe, V. S. Doshi May 2008

Particle Composition And Size Distributions In And Around A Deep Pit Swine Operation, Randy S. Martin, P. J. Silva, Kori D. Moore, M. Erupe, V. S. Doshi

Civil and Environmental Engineering Faculty Publications

The contribution of emissions from agricultural facilities is rapidly becoming a major concern for local and regional air quality. Characterization of particle properties such as physical size distribution and chemical composition can be valuable in understanding the processes contributing to emissions and ultimate fate of particulate matter from agricultural facilities. A measurement campaign was conducted at an Iowa, deep-pit, three-barn swine finishing facility to characterize near-source ambient particulate matter. Size-specific mass concentrations were determined using minivol samplers, with additional size distribution information obtain using optical particle counters. Particulate composition was determined via ion chromatographic analysis of the collected filters. A …


Tribological And Antiwear Mechanisms Of Fluorinated Zinc Dialkyl Dithiophosphate In Comparison To Zinc Dialkyl Dithiophosphate In Engine Oils, Ramoun Mourhatch May 2008

Tribological And Antiwear Mechanisms Of Fluorinated Zinc Dialkyl Dithiophosphate In Comparison To Zinc Dialkyl Dithiophosphate In Engine Oils, Ramoun Mourhatch

Material Science and Engineering Dissertations - Archive

Tribofilms generated in wear tests using lubricants containing fluorinated ZDDP and ZDDP were studied. Fluorinated ZDDP demonstrated superior wear performance compared to ZDDP under tribological conditions even at lower phosphorus levels. Chemical properties and the molecular structure of the fluorinated ZDDP were examined and presented in a previous companion study by Parekh and Aswath [1] using techniques such as NMR and DSC while this study examines the tribological behavior of this compound and the characteristics of the tribofilms formed by it. Ball on cylinder tribological tests were conducted with lubricants containing this new fluorinated thiophosphate compound and compared to lubricants …


A Study Of The Antiwear Behavior And Oxidation Stability Of Fluorinated Zinc Dialkyl Dithio Phosphate In The Presence Of Antioxidants, Anuradha Somayaji May 2008

A Study Of The Antiwear Behavior And Oxidation Stability Of Fluorinated Zinc Dialkyl Dithio Phosphate In The Presence Of Antioxidants, Anuradha Somayaji

Material Science and Engineering Dissertations - Archive

The antiwear additive Zinc dialkyl dithio phosphate (ZDDP) is one of the most important components of engine-oil additives and a major source of phosphorus. Phosphorus plays a crucial part in mitigating engine wear, yet has been proven harmful to modern catalytic converters. Progressive regulatory caps on phosphorus content in automotive lubricants have led to widespread efforts to reduce its levels. A new fluorinated ZDDP (F-ZDDP) complex developed at the University of Texas at Arlington has found to breakdown at lower temperatures compared to ZDDP and has showed better wear performance than ZDDP alone. This would allow the possibility of further …


Trajectory Optimization Using Collocation And Evolutionary Programming For Constrained Nonlinear Dynamical Systems, Brandon Merle Shippey May 2008

Trajectory Optimization Using Collocation And Evolutionary Programming For Constrained Nonlinear Dynamical Systems, Brandon Merle Shippey

Mechanical and Aerospace Engineering Theses - Archive

Trajectory design and optimization has a broad variety of applications in fields such as aerospace and electrical engineering. The solution of a trajectory that minimizes a cost function subject to nonlinear differential equations of motion and various types of constraints may be obtained by the methods of optimal control theory. A framework is presented for numerical solution of the optimal control problem. The solution is converted to that of a constrained discrete parameter optimization problem. Direct collocation and nonlinear programming are used to perform a local gradient-based search for the optimal solution. A genetic algorithm combined with a shooting method …


Regenerative Peripheral Neurointerfacing Of Upper Extremity Prostheses, Kshitija Garde May 2008

Regenerative Peripheral Neurointerfacing Of Upper Extremity Prostheses, Kshitija Garde

Bioengineering Theses - Archive

Current robotic prosthetic devices provide limited functionality to the user as they rely on gross myogenic control and lack critical sensory feedback needed for fine movement control. Interfacing the nervous system with the robotic prosthesis would facilitate amputees to control them naturally, in resemblance to the human hand. Functional neuro-electrode connections have been demonstrated in the brain and peripheral nervous system; however, gliosis, micro hemorrhages, axonopathy and excessive inflammation limit their long-term use. We evaluated the possibility of enticing peripheral nerve regeneration through a multi-electrode array with an open architecture as an alternative to enhance longevity of nerve-electrode interface. Regenerative …


Design For Reliability In Microoptelectromechanical Systems (Moems), Abiodun Abiodun Fasoro May 2008

Design For Reliability In Microoptelectromechanical Systems (Moems), Abiodun Abiodun Fasoro

Mechanical and Aerospace Engineering Dissertations - Archive

Microelectromechanical systems (MEMS) is an enabling technology for miniaturization. MEMS consist of micron sized moving mechanical structures and electronics fabricated on a suitable substrate such as silicon. MEMS has found applications in virtually every aspect of human life, ranging from the automobile to the aerospace, and from the telecommunications to the consumer electronic industries. Technology integration has led to several subsets of MEMS e.g. microoptoelectromechanical systems (MOEMS), radio-frequency MEMS (RF MEMS), etc. Together with these added functionalities, by way of technology integration come additional issues and challenges never before experienced by packaging engineers. MEMS and MOEMS package requirements vary widely …


Dynamic Modeling, Control And Optimization Of Pem Fuel Cell System For Automotive And Power System Applications, Woon Ki Na May 2008

Dynamic Modeling, Control And Optimization Of Pem Fuel Cell System For Automotive And Power System Applications, Woon Ki Na

Electrical Engineering Dissertations - Archive

This dissertation is focusing on fuel cell dynamic modeling and control, the optimization design of fuel cell systems, power electronics interface designs, and control for the fuel cell based hybrid system. First, a dynamic PEM fuel cell model is proposed as a nonlinear, multiple-input, multiple-output (MIMO) system so that feedback linearization can be directly utilized and the PEM fuel cells can be protected through the controller. For the design of the dynamic model PEM fuel cells, all possible water effects are considered, and the anode and cathode gas pressures, as well as the fuel cell voltage are defined as the …


Biaxial Mechanical Characterization Of Porcine Periosteum, Phillip Daniel Warren May 2008

Biaxial Mechanical Characterization Of Porcine Periosteum, Phillip Daniel Warren

Bioengineering Theses - Archive

Periosteum is multipotent tissue responsible for cortical bone deposition and is important in fracture repair. Research indicates the periosteum is mediated by similar mechanical signals to those that mediate bone growth and remodeling. Therefore, biaxial mechanical characterization of periosteum can be very informative, indeed. This paper presents the results of the first such examination. The porcine periosteum herein has at least three distinct layers - a cellular layer, an elastin-rich layer, and a collagen-rich layer - the latter two providing structural integrity. Not surprisingly then, the general biaxial mechanical characteristics of periosteum resemble those of other collagen and/or elastin-rich membranes. …


Composition - Microstructure - Property Relationships In Dual Phase Bulk Magnetoelectric Composite, Rashed Adnan Islam May 2008

Composition - Microstructure - Property Relationships In Dual Phase Bulk Magnetoelectric Composite, Rashed Adnan Islam

Material Science and Engineering Dissertations - Archive

The coexistence of coupled electrical and magnetic properties in the “magnetoelectric” material has led to the possibility of developing smarter and smaller electronic components. In order to make this possibility a reality, significant efforts are required to understand the science of magnetoelectric (ME) behavior and apply this understanding to develop higher sensitivity material. The primary aims of this thesis are to identify the role of composition, microstructural variables, composite geometry, texturing, post sintering heat treatment, and nanoscale assembly on ME coefficient. The overall objective is to synthesize, characterize and utilize a high ME coefficient composite. The desired range of ME …


Voltage Profile Estimation And Reactive Power Control Of Distribution Feeders, David Timothy Chessmore May 2008

Voltage Profile Estimation And Reactive Power Control Of Distribution Feeders, David Timothy Chessmore

Electrical Engineering Dissertations - Archive

Distribution systems are important transportation links for the delivery of electric power. Understanding the system conditions of distribution feeders is vital for controlling power systems and maintaining electricity flow on power grids. With better knowledge of the system conditions on distribution feeders, a deliberate and systematic approach can be taken to achieve more efficient and reliable power delivery. Furthermore, better understanding of system conditions can be useful in reducing operation and maintenance costs in various power system applications such as voltage control and capacitor bank switching. This dissertation presents a novel method for estimating the voltage profile of a radial …


Simultaneous Robot Localization And Mapping Of Parameterized Spatio-Temporal Fields Using Multi-Scale Adaptive Sampling, Muhammad Faizan Mysorewala May 2008

Simultaneous Robot Localization And Mapping Of Parameterized Spatio-Temporal Fields Using Multi-Scale Adaptive Sampling, Muhammad Faizan Mysorewala

Electrical Engineering Dissertations - Archive

This dissertation presents a Multi-scale Adaptive Sampling (AS) framework for combining measurements arriving from mobile robotic sensors of different scales, rates and accuracies, in order to reconstruct a parametric spatio-temporal field. The proposed sampling algorithm, "EKF-NN-GAS", is based on the Extended Kalman Filter (EKF), Radial Basis Function (RBF) Neural Networks and Greedy Search Heuristics. This novel AS algorithm responds to real-time measurements by continuously directing robots to locations most likely to yield maximum information about the sensed field. EKF is used to derive quantitative information measures for sampling locations. In addition, the localization uncertainty of the robots is minimized by …