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2004

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Articles 2041 - 2070 of 2785

Full-Text Articles in Engineering

Swarm Intelligence For Digital Circuits Implementation On Field Programmable Gate Arrays Platforms, Ganesh K. Venayagamoorthy, Venu Gopal Gudise Jan 2004

Swarm Intelligence For Digital Circuits Implementation On Field Programmable Gate Arrays Platforms, Ganesh K. Venayagamoorthy, Venu Gopal Gudise

Electrical and Computer Engineering Faculty Research & Creative Works

Field programmable gate arrays (FPGAs) are becoming increasingly important implementation platforms for digital circuits. One of the necessary requirements to effectively utilize the FPGA's resources is an efficient placement and routing mechanism. This paper presents an optimization technique based on swarm intelligence for FPGA placement and routing. Mentor graphics technology mapping netlist file is used to generate initial FPGA placements and routings which are then optimized by particle swarm optimization (PSO). Results for the implementation of a binary coded decimal bidirectional counter and an arithmetic logic unit on a Xilinx FPGA show that PSO is a potential technique for solving …

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Mixing Electromagnetic And Electrical Circuit Simulations, W. C. Chew, Y. H. Chu, L. (Lijun) J. Jiang, I. T. Chiang, Y. C. Pan, J. S. Zhao Jan 2004

Mixing Electromagnetic And Electrical Circuit Simulations, W. C. Chew, Y. H. Chu, L. (Lijun) J. Jiang, I. T. Chiang, Y. C. Pan, J. S. Zhao

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Metal Transfer In Arc Welding, Hai-Lung Tsai, P.-C. Wang Jan 2004

Metal Transfer In Arc Welding, Hai-Lung Tsai, P.-C. Wang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A double pulse welding current method is disclosed for the generation and transfer of droplets of welding metal from an electrode wire to a workpiece in an arc welding process. A suitable background direct current level is specified to deliver a desired number of droplets to the weld site. During each cycle of droplet formation and transfer, a first increased current pulse is applied to the electrode and arc to generate a droplet on the tip of and electrode and then a second further increased current pulse is applied to timely separate the droplet from the electrode for transport in …

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Optical Characterization Of Ceramic Thin Films: Applications In Low-Temperature Solid Oxide Fuel-Cell Materials Research, B. P. Gorman, V. Petrovsky, Harlan U. Anderson, T. Petrovsky Jan 2004

Optical Characterization Of Ceramic Thin Films: Applications In Low-Temperature Solid Oxide Fuel-Cell Materials Research, B. P. Gorman, V. Petrovsky, Harlan U. Anderson, T. Petrovsky

Materials Science and Engineering Faculty Research & Creative Works

Characterization of thin film solid oxide fuel-cell materials can be difficult due to the range of porosities in electrodes and electrolytes as well as the nano-sized pores and particles. in this study, optical characterization techniques such as ultraviolet-visible transmission and reflection spectrophotometry are illustrated as methods for achieving information about the film density from the film refractive index as well as the film thickness. These techniques were used to investigate the sintering process of colloidal CeO2 on sapphire substrates and polymeric precursor-derived ZrO2:16%Y (YSZ) thin films on silicon over the temperature range 400-1000 °C, and the results …

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Airframe Noise Modeling Appropriate For Multidisciplinary Design And Optimization, Serhat Hosder, Bernard Grossman, Joseph A. Schetz, William H. Mason Jan 2004

Airframe Noise Modeling Appropriate For Multidisciplinary Design And Optimization, Serhat Hosder, Bernard Grossman, Joseph A. Schetz, William H. Mason

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A Trailing Edge Noise Metric has been developed for constructing response surfaces that may be used for optimization problems involving aerodynamic noise from a clean wing. The modeling approach includes a modified version of a theoretical trailing edge noise prediction and utilizes a high fidelity CFD (RANS) code with a two-equation turbulence model to obtain the characteristic velocity and length scales used in the noise model. The noise metric is not the absolute value of the noise intensity, but an accurate relative noise measure as shown in the validation studies. Parametric studies were performed to investigate the effect of the …

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Automatic Feedback Control Of Mechanical Gas Face Seals Via Clearance Control, Sachin S. Yelma, Robert G. Landers, Brad A. Miller Jan 2004

Automatic Feedback Control Of Mechanical Gas Face Seals Via Clearance Control, Sachin S. Yelma, Robert G. Landers, Brad A. Miller

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An approach based on proper orthogonal decomposition and Galerkin projection is presented for developing low-order nonlinear models of the gas film pressure within mechanical gas face seals. A technique is developed for determining an optimal set of global basis functions for the pressure field using data measured experimentally or obtained numerically from simulations of the seal motion. The reduced-order gas film models are shown to be computationally efficient compared to full-order models developed using the conventional semidiscretization methods. An example of a coned mechanical gas face seal in a flexibly mounted stator configuration is presented. Axial and tilt modes of …

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Characterization And Modeling Of Local Electromechanical Response In Stress-Biased Piezoelectric Actuators, N. Navapan-Traiphol, Robert W. Schwartz, Daniel S. Stutts, J. Wood Jan 2004

Characterization And Modeling Of Local Electromechanical Response In Stress-Biased Piezoelectric Actuators, N. Navapan-Traiphol, Robert W. Schwartz, Daniel S. Stutts, J. Wood

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Numerous investigators have explored the factors that contribute to the high electromechanical performance of stress-biased actuators with particular attention being given to the importance of the extrinsic (domain wall translation) response mechanism. Based on the variation in lateral stress through the thickness of the piezoelectric layer within these devices, it has been suggested that the piezoelectric coefficient varies as a function of position within the layer, though no direct evidence has been previously presented. In this study, the results of Moire interferometry investigations of local strains within these devices are reviewed. The technique permits effective depth-profiling of local deformations at …

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Development And Implementation Of New Nonlinear Control Concepts For A Ua, Vijayakumar Janardhan, Derek Schmitz, S. N. Balakrishnan Jan 2004

Development And Implementation Of New Nonlinear Control Concepts For A Ua, Vijayakumar Janardhan, Derek Schmitz, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A reconfigurable flight control method is developed to be implemented on an Unmanned Aircraft (UA), a thirty percent scale model of the Cessna 150. This paper presents the details of the UAV platform, system identification, reconfigurable controller design, development, and implementation on the UA to analyze the performance metrics. A Crossbow Inertial Measurement Unit provides the roll, pitch and yaw accelerations and rates along with the roll and pitch. The 100400 mini-air data boom from spaceage control provides the airspeed, altitude, angle of attack and the side slip angles. System identification is accomplished by commanding preprogrammed inputs to the control …

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Development And Analysis Of A Feedback Treatment Strategy For Parturient Paresis Of Cows, Radhakant Padhi, S. N. Balakrishnan Jan 2004

Development And Analysis Of A Feedback Treatment Strategy For Parturient Paresis Of Cows, Radhakant Padhi, S. N. Balakrishnan

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An intelligent on-line feedback treatment strategy based on nonlinear optimal control theory is presented for the parturient paresis of cows. A limitation in the development of an existing nonlinear mathematical model for the homogeneous system is addressed and further modified to incorporate a control input. A neural network based optimal feedback controller is synthesized for the treatment of the disease. Detailed studies are used to analyze the effectiveness of a feedback medication strategy and it is compared with the current "impulse" strategy. The results show that while the current practice may fail in some cases, especially if it is carried …

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Solid State Aircraft Concept Overview, M. Shahinpoor, P. Jenkins, C. Smith, Kakkattukuzhy M. Isaac, T. Dalbello, Anthony Colozza Jan 2004

Solid State Aircraft Concept Overview, M. Shahinpoor, P. Jenkins, C. Smith, Kakkattukuzhy M. Isaac, T. Dalbello, Anthony Colozza

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Due to recent advances in polymers, photovoltaics, and batteries a unique type of aircraft may be feasible. This is a "solid-state" aircraft, with no conventional mechanical moving parts. Airfoil, propulsion, energy production, energy storage and control are combined in an integrated structure. The key material of this concept is an ionic polymeric-metal composite (IPMC) that provides source of control and propulsion. This material has the unique capability of deforming in an electric field and returning to its original shape when the field is removed. Combining the IPMC with thin-film batteries and thin-film photovoltaics provides both energy source and storage in …

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Discrete-Time Neural Network Output Feedback Control Of Nonlinear Systems In Non-Strict Feedback Form, P. He, Sarangapani Jagannathan Jan 2004

Discrete-Time Neural Network Output Feedback Control Of Nonlinear Systems In Non-Strict Feedback Form, P. He, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

An adaptive neural network (NN) -Based output feedback controller is proposed to deliver a desired tracking performance for a class of discrete-time nonlinear systems, which is represented in non-strict feedback form. the NN backstepping approach is utilized to design the adaptive output feedback controller consisting of 1) a NN observer to estimate the system states with the input-output data, and 2) two NNs to generate the virtual and actual control inputs, respectively. the non-causal problem in the discrete time backstepping design is avoided by using the universal NN approximator. the persistence excitation (PE) condition is relaxed both in the NN …

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Prediction Of Rotor Position At Standstill And Flying Shaft Conditions In Switched Reluctance Machines, M. Krishnamurthy, C. S. Edrington, Babak Fahimi Jan 2004

Prediction Of Rotor Position At Standstill And Flying Shaft Conditions In Switched Reluctance Machines, M. Krishnamurthy, C. S. Edrington, Babak Fahimi

Electrical and Computer Engineering Faculty Research & Creative Works

Development of a reliable, smooth, and precise position sensor less startup routine is an integral part of the Switched Reluctance Machine (SRM) control. the proposed sensor less startup method presented in this paper represents high grade performance and does not require additional hardware or memory. Further, the proposed sensor less technique is extended to flying shaft conditions. These capabilities are highly demanded by automotive applications such as starter/alternator and electric power steering systems. an assessment of the impact of motor parameters and diagnostic signal measurement on the quality of the sensor less startup method is also included. This will help …

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Reinforcement Learning-Based Output Feedback Control Of Nonlinear Systems With Input Constraints, P. He, Sarangapani Jagannathan Jan 2004

Reinforcement Learning-Based Output Feedback Control Of Nonlinear Systems With Input Constraints, P. He, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

A novel neural network (NN) -Based output feedback controller with magnitude constraints is designed to deliver a desired tracking performance for a class of multi-input-multi-output (MIMO) discrete-time strict feedback nonlinear systems. Reinforcement learning in discrete time is proposed for the output feedback controller, which uses three NNs: 1) a NN observer to estimate the system states with the input-output data; 2) a critic NN to approximate certain strategic utility function; and 3) an action NN to minimize both the strategic utility function and the unknown dynamics estimation errors. the magnitude constraints are manifested as saturation nonlinearities in the output feedback …

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An Improved Optimal Elemental Method For Updating Finite Element Models, Zhongdong Duan, B. F. Spencer, Guirong Yan, Jinping Ou Jan 2004

An Improved Optimal Elemental Method For Updating Finite Element Models, Zhongdong Duan, B. F. Spencer, Guirong Yan, Jinping Ou

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Optimal Matrix Method and Optimal Elemental Method Used to Update Finite Element Models May Not Provide Accurate Results. This Situation Occurs When the Test Modal Model is Incomplete, as is Often the Case in Practice. an Improved Optimal Elemental Method is Presented that Defines a New Objective Function, and as a Byproduct, Circumvents the Need for Mass Normalized Modal Shapes, Which Are Also Not Readily Available in Practice. to Solve the Group of Nonlinear Equations Created by the Improved Optimal Method, the Lagrange Multiplier Method and Matlab Function Fmincon Are Employed. to Deal with Actual Complex Structures, the Float-Encoding …

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Deformation Analysis Of Missouri Bridge Approach Embankments, Jonathan L. Robison, Ronaldo Luna Jan 2004

Deformation Analysis Of Missouri Bridge Approach Embankments, Jonathan L. Robison, Ronaldo Luna

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Missouri has recently experienced below expectation performance or "the bump-at-the-end of the bridge" phenomena at bridge approach slab transitions. Information on approach slab performance was collected state wide to assess if the problem was limited to regional or geological distribution. Finite element analysis was then used to explore the soil embankment-bridge structure differential settlement in two Missouri bridges; MoDOT Bridge A6031 in Livingston County, and MoDOT Bridge A5834 in Pulaski County. These two cases are indicative of the types of soil conditions encountered in the Northern Glaciated Plains region (deeper compressible foundation soils) and the Southern Ozarks region (shallow rocky …

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A Theoretical And Numerical Study Of Thin Film Delamination Using The Pull-Off Test, Zuo Sun, Kai-Tak Wan, David A. Dillard Jan 2004

A Theoretical And Numerical Study Of Thin Film Delamination Using The Pull-Off Test, Zuo Sun, Kai-Tak Wan, David A. Dillard

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An accurate closed-form analytical solution for the strain energy release rate for a thin rectangular film loaded by a central line force using the pull-off test is derived in the presence of a tensile residual stress. the theoretical constitutive relation and the strain energy release rate agree very well with two-dimensional nonlinear finite element analysis for the entire deformation regime ranging from bending plate to stretching membrane. Fracture modes for this pull-off test are also investigated based upon the finite element analysis, offering additional insights to the interfacial delamination. © 2003 Elsevier Ltd. All rights reserved.

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Adjusting The Low Energy Threshold For Large Bodies In Pet, John W. Wilson, Timothy G. Turkington, James G. Colsher Jan 2004

Adjusting The Low Energy Threshold For Large Bodies In Pet, John W. Wilson, Timothy G. Turkington, James G. Colsher

Mining Engineering Faculty Research & Creative Works

The performance of a PET scanner on three different phantom sizes was studied as a function of low energy threshold (LET). Phantom cross sections ranged from 20 cm diameter circular to 28 cm x 43 cm oval and LET''s ranged from 350 keV to 475 keV, in 25 keV increments. System sensitivity, scatter fraction, and NEC were measured over a wide range of radioactivity levels. Increasing the low energy threshold lowered both sensitivity and scatter fraction. The statistical quality of the raw data was maximized for the 425 keV setting for all three phantoms. System stability and uniformity of response …

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Characterization Of Human Metal Esd Reference Discharge Event And Correlation Of Generator Parameters To Failure Levels-Part Ii: Correlation Of Generator Parameters To Failure Levels, Kai Wang, David Pommerenke, Ramachandran Chundru, Thomas Van Doren, Jiu Sheng Huang, Federico Centola Jan 2004

Characterization Of Human Metal Esd Reference Discharge Event And Correlation Of Generator Parameters To Failure Levels-Part Ii: Correlation Of Generator Parameters To Failure Levels, Kai Wang, David Pommerenke, Ramachandran Chundru, Thomas Van Doren, Jiu Sheng Huang, Federico Centola

Electrical and Computer Engineering Faculty Research & Creative Works

Most electrostatic discharge (ESD) generators are built in accordance with the IEC 61000-4-2 specifications. It is shown, that the voltage induced in a small loop correlates with the failure level observed in an ESD failure test on the systems comprised of fast CMOS devices, while rise time and derivative of the discharge current did not correlate well. The electric parameters of typical ESD generators and ESD generators that have been modified to reflect the current and field parameters of the human metal reference event are compared and the effect on the failure level of fast CMOS electronics is investigated. The …

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Distributed Power Control Of Cellular Networks In The Presence Of Channel Uncertainties, Maciej Jan Zawodniok, Q. Shang, Jagannathan Sarangapani Jan 2004

Distributed Power Control Of Cellular Networks In The Presence Of Channel Uncertainties, Maciej Jan Zawodniok, Q. Shang, Jagannathan Sarangapani

Electrical and Computer Engineering Faculty Research & Creative Works

A novel distributed power control (DPC) scheme for cellular networks in the presence of radio channel uncertainties such as path loss shadowing, and Rayleigh fading is presented. Since these uncertainties can attenuate the received signal strength and can cause variations in the received Signal-to-lnterference ratio (SIR), the proposed DPC scheme maintains a target SIR at the receiver provided the uncertainty is slowly varying with time. The DPC estimates the time varying nature of the channel quickly and uses the information to arrive at a suitable transmitter power value . Further, the standard assumption of a constant interference during a link's …

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Jecp/Sp: A Computer Program For Generating Stereographic Projections, Applicable To Specimen Orientation Adjustment In Tem Experiments, Xingzhong Li Jan 2004

Jecp/Sp: A Computer Program For Generating Stereographic Projections, Applicable To Specimen Orientation Adjustment In Tem Experiments, Xingzhong Li

Nebraska Center for Materials and Nanoscience: Faculty Publications

In the present work, a computer program was written for generating stereographic projections and was also extended as an application for specimen orientation adjustment in TEM experiments. JECP/SP is a fully functional tool for generating stereographic projections in direct and reciprocal space. JECP/SP has been extended as an application for specimen orientation adjustment using a TEM holder. JECP/SP can be used as a teaching aid for students in crystallography as well as a practical tool for scientists performing TEM experiments.

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Fee -Based Online Services : Exploring Consumers’ Willingness To Pay, L. Richard Ye, Yue Zhang, Dat-Dao Nguyen, James Chiu Jan 2004

Fee -Based Online Services : Exploring Consumers’ Willingness To Pay, L. Richard Ye, Yue Zhang, Dat-Dao Nguyen, James Chiu

Journal of International Technology and Information Management

Many online service businesses are beginning to charge fees for services that they used to provide for free. It is unclear whether consumers are ready to embrace this practice. This study explores consumer attitudes toward fee-based online services. The results of the study indicate that consumers’ willingness to pay for online services is likely to be influenced by their perceived value of convenience these services provide, and by the extent to which they utilize these services. While consumers appear more willing to pay for services that are qualitatively better than free services, there is also indication that the belief remains …

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Information Systems Service Quality Measurement: The Evolution Of The Servqual Instrument, Dwayne Whitten Jan 2004

Information Systems Service Quality Measurement: The Evolution Of The Servqual Instrument, Dwayne Whitten

Journal of International Technology and Information Management

Due to the increasing service component of information technology, service quality measurement has become increasingly important as IS practitioners attempt to increase service quality to customers. The measurement of service quality in IS evolved from the research done in the marketing literature. The SERVQUAL instrument has evolved to become the most commonly used measurement instrument in both IS and marketing. Although commonly used, the SERVQUAL instrument is not without criticism. This paper describes the SERVQUAL instrument, its criticisms and support, and finally the SERVPERF instrument, a variation of the SERVQUAL instrument which is an attempt at improving upon the SERVQUAL …

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Empirical Evidence Of Diminishing Payoff From Successive Generations Of Information Systems, Gerald E. Evans, Neil Morton Jan 2004

Empirical Evidence Of Diminishing Payoff From Successive Generations Of Information Systems, Gerald E. Evans, Neil Morton

Journal of International Technology and Information Management

Previous research has focused on a number of important variables that can influence the observed payoffs from information systems investments. In the current investigation conducted in the spring of 2002, personal, on-site interviews were conducted in 138 small and medium sized businesses. Vendor involvement in systems development was less related to systems cost than previously. Unfortunately, vendor involvement was unrelated to any of the four measures of systems success in the entire sample. Further analysis revealed a strong relationship between information system generation and payoffs. Specifically, there appeared to be a point of diminishing return with subsequent generations of information …

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Online Reverse Auctions: An Overview, Ching-Chung Kuo, Pamela Rogers, Richard E. White Jan 2004

Online Reverse Auctions: An Overview, Ching-Chung Kuo, Pamela Rogers, Richard E. White

Journal of International Technology and Information Management

Electronic commerce (e-commerce) is the fastest growing area in the U.S. economy with electronic procurement (e-procurement) being a major component, and online reverse auctions (ORAs) have emerged as a key e-procurement tool. Since the mid-1990s, ORAs have been gaining in popularity because of their potentially significant positive impact on the profitability of both the buyers and the sellers. Much has been written about the new purchasing paradigm and numerous stories have been reported recently. This paper is aimed at providing a critical review of ORAs by examining their historical developments, different forms, advantages, and disadvantages. In addition, 10 important factors …

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Modeling The Hydrologic And Particulate Loadings From Paved Urban Surfaces, Chad Michael Cristina Jan 2004

Modeling The Hydrologic And Particulate Loadings From Paved Urban Surfaces, Chad Michael Cristina

LSU Doctoral Dissertations

This dissertation details the results of recent investigations concerning non-colloidal particulate matter found in urban rainfall-runoff and urban snowmelt. Three forms of the power law model (PLM) were used to model particle number density. It was found that significant model error could be introduced into PLMs when the median diameter particle was used to estimate the number of particles per interval, but the SSE of continuous PLMs could be significantly reduced through the use of correction factors when the sieve interval was large (P<0.05). Additionally, a multiple PLM analysis may be more appropriate than a single PLM analysis when changes in particle population occur within a single gradation. PLMs were also used to model the relationship between cumulative granulometric mass and cumulative particulate-bound metal mass. The use of such calibrated PLMs provided considerable cost reduction when compared to conventional direct measurements of particulate-bound metal mass. A first flush analysis indicated that only events with average volumetric flow rates approaching 1 L/min/m of drainage width exhibit a rapid depletion of particulate matter consistent with the concentration-based definition of the first flush. An analysis of particle separation mechanisms indicated that 90% of these particles, by mass, could be removed from the discharge with detention times of 30 min and 120 min for snowmelt and rainfall-runoff, respectively, in a typical roadside drainage system. It was also found that the kinematic wave model could accurately model significant aspects of rainfall-runoff events in traffic-impacted watersheds provided that abstractions were incorporated into the modeling process. For this watershed the source of abstraction was attributable to vehicular traffic. For high-intensity events with more than 10 vehicles per runoff volume (VPV) the runoff coefficient varied between 0.6 and 0.9 while for low-intensity events with fewer than 10 VPV the coefficient ranged between 0.2 and 0.4.

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Processing, Microstructure And Mechanical Behavior Of Nanocomposite Multilayers, Zuqiang Qi Jan 2004

Processing, Microstructure And Mechanical Behavior Of Nanocomposite Multilayers, Zuqiang Qi

LSU Doctoral Dissertations

Nanoscale multilayer coatings have high potential for numerous engineering applications because they can exhibit enhanced properties due to nanoscale effects and combine different properties from individual components. At present, scale effects on the mechanical behavior of multilayers are not well understood. Three multilayer nanocomposite systems, namely Al/Al2O3, Ti/TiN, and Cr/a-C, have been synthesized by using a dual-gun e-beam physical vapor deposition, to investigate the effect of layer thickness, the nature of components and their microstructures on the mechanical behavior. The deposited Al and Ti nanolayers were found to have polycrystalline fcc and hcp structure, respectively, the Cr and TiN layers …

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Kentucky Traffic Collision Facts 2004 Report, Kentucky Transportation Center, Kentucky State Police Jan 2004

Kentucky Traffic Collision Facts 2004 Report, Kentucky Transportation Center, Kentucky State Police

Kentucky Transportation Center Research Report

KENTUCKY’S TRAFFIC COLLISION FACTS report for 2004 is based on collision reports submitted to the Kentucky State Police Records Branch. As required by Kentucky Revised Statutes 189.635, “every law enforcement agency whose officers investigate a vehicle accident of which a report must be made...shall file a report of the accident...within ten days after investigation of the accident upon forms supplied by the bureau.” The stated purpose of this requirement is to utilize data on traffic collisions for such purposes as will improve the traffic safety program in the Commonwealth. Data contained in this report are based solely on the observations …

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Excimer Emission From Cathode Boundary Layer Discharges, Mohamed Moselhy, Karl H. Schoenbach Jan 2004

Excimer Emission From Cathode Boundary Layer Discharges, Mohamed Moselhy, Karl H. Schoenbach

Bioelectrics Publications

The excimer emission from direct current glow discharges between a planar cathode and a ring-shaped anode of 0.75 and 1.5 mm diameter, respectively, separated by a gap of 250 μm, was studied in xenon and argon in a pressure range from 75 to 760 Torr. The thickness of the “cathode boundary layer” plasma, in the 100 μm range, and a discharge sustaining voltage of approximately 200 V, indicates that the discharge is restricted to the cathode fall and the negative glow. The radiant excimer emittance at 172 nm increases with pressure and reaches a value of 4 W/cm2 for …

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Microscopic Analysis For Water Stressed By High Electric Fields In The Prebreakdown Regime, R. P. Joshi, J. Qian, K. H. Schoenbach, E. Schamiloglu Jan 2004

Microscopic Analysis For Water Stressed By High Electric Fields In The Prebreakdown Regime, R. P. Joshi, J. Qian, K. H. Schoenbach, E. Schamiloglu

Bioelectrics Publications

Analysis of the electrical double layer at the electrode-water interface for voltages close to the breakdown point has been carried out based on a static, Monte Carlo approach. It is shown that strong dipole realignment, ion-ion correlation, and finite-size effects can greatly modify the electric fields and local permittivity (hence, leading to optical structure) at the electrode interface. Dramatic enhancements of Schottky injection, providing a source for electronic controlled breakdown, are possible. It is also shown that large pressures associated with the Maxwell stress tensor would be created at the electrode boundaries. Our results depend on the ionic density, and …

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The Frequency Distribution Of Quantization Error In Digitizers For Coherent Sampling, Sol Neeman Ph.D. Jan 2004

The Frequency Distribution Of Quantization Error In Digitizers For Coherent Sampling, Sol Neeman Ph.D.

Engineering Studies Faculty Publications and Creative Works

In this paper the frequency distribution of quantization error in coherent sampling of digitizers will be investigated. As the distribution of the quantization error affects the values of THD and SNR, it is relevant for a correct interpretation of THD and SNR of sine waves in coherent sampling. The distribution of the quantization error will be analyzed as a function of N, total number of samples and M, number of cycles in the sample set and it will be proved that for certain cases, the quantization error falls on odd harmonics only of the frequency of the sampled sine wave.

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