Engineering Commons^™

Resonant Tank Motor Model For Voltage Reflection Simulations With Pwm Drives, Davia W. Schlegel, Glenn T. Wrate, Russ Kerkman, Gary Skibinski

Conference Papers in Published Proceedings

Reflected wave transient voltages that are impressed on drive output cables and low voltage AC induction motors are normally simulated with steep fronted dv/dt pulse waveforms from PWM voltage source inverters. System simulation arises from a need to correlate reflected wave peak voltage and risetime with the dielectric insulation capability of both the motor and cable. To obtain reasonable results, accurate models of each component must be employed. This investigation concentrates on parameter identification for a high frequency resonant tank motor model from fractional to several hundred horsepower.

Variable Angle Of Incidence Analysis Of Magneto-Optic Multilayers, William A. Mcgahan, Liang-Yao Chen, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

We have applied the technique of variable angle of incidence spectroscopic ellipsometry (VASE) to the analysis of multilayered magneto-optic structures. With this instrument we measure the complete pseudodielectric tensor (diagonal and off-diagonal elements) for the sample of interest at variable angles of incidence. We have also developed computer software to perform a best-fit analysis of the measured data, providing optical constants, Voigt parameters, and layer thicknesses for the individual layers in the sample. Additionally, given an estimate of the material parameters, this software will provide an estimate of the optimum spectral range and angles of incidence for accurate characterization of …

Chu Spaces - A New Approach To Diagnostic Information Fusion, Hung T. Nguyen, Vladik Kreinovich, Berlin Wu

Departmental Technical Reports (CS)

This paper is rather theoretical. Its aim is to describe a general algebraic framework, known as Chu spaces, in which different type of information can be transformed into the same form, so that fusion procedures can be investigated in a single general framework.

Weber Basin Water Quality Optimization, P. Wayne Hale Ii, Elizabeth Hales, Kade Moncur, Jonathan Oldham

Undergraduate Honors Capstone Projects

Salt Lake City, after evaluating its projected water needs for the next 25 years, has proposed to route 300 MGD of water via pipeline from the Bear River to Salt Lake's culinary water system. According to Weber Basin Water Conservancy District officials, this water will be available between October and March (the irrigation off-season). En route to the system, the water will pass through an area known as the "Slaterville Diversion" subsequent to water treatment at a new plant. The Diversion is currently the mixing point for several water sources. These waters need to be managed and mixed appropriately with …

Water Resource Potential Of The Rio-Grande River Basin In Bolivia, José Luis Chávez Egüez

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

The exploiting of water resources in developing countries is fundamental for stabilizing population growth, and promoting efficient agriculture. The development of water resources allows the utilization of modern irrigation systems and methodologies.

Recently developed methods to predict runoff from rainfall data are applied to a Bolivian watershed. A study in Honduras yielded a good response to the method that utilizes Moisture Availability Index (MAI) to predict runoff, but the coefficients of that relation could not be related to MAI or to the difference between average weather station elevation and average basin elevation in the Rio Grande Upper Basin in Bolivia. …

Acuta Enews May 1999, Vol. 28, No. 5

ACUTA Newsletters

In This Issue

Board Approves Slate of Nominees

Moderators & Monitors Needed in Nashville!

Board Report

Who Pays for Cellular Calls?

DC at a Glance

Positions Available

Welcome New Members

Directivity Patterns Of Acoustic Radiation From Bowed Violins, Lily M. Wang, Courtney B. Burroughs

Durham School of Architectural Engineering and Construction: Faculty Publications

Directivity patterns of acoustic radiation have been measured in the far-field of a violin, excited with an open-frame mechanical bowing machine. Analysis of the directivity patterns confirms that, at frequencies below 600 Hz, the violin radiates omnidirectionally, while above 600 Hz, certain trends are apparent as the patterns become increasingly complex. It is noted that when different strings are excited, the far-field radiation patterns observed at nearly the same frequency are similar, even in higher frequency ranges where modal overlap is high. When the difference in frequency between two directivity patterns exceeds some fraction of a semitone, though, the measured …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 5, May 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Reversal Flow In Fixed-Bed Reactors Operating Under Reaction-Regeneration Cycles, Daniel O. Borio, Noemi S. Schbib, Jorge E. Gatica

Chemical & Biomedical Engineering Faculty Publications

The unsteady state simulation of a set of industrial fixed-bed reactors is presented. The catalytic dehydrogenation of 1-butene into 1-3-butadiene is selected as case study. These reactors operate under reaction-regeneration cycles. Each stage of the process, i.e., dehydrogenation (deactivation by coking), steam purge, oxidative regeneration and evacuation, is simulated by means of the corresponding dynamic model. The kinetic parameters used in the dehydrogenation and regeneration stages for a Cr₂O₃/Al₂O₃ catalyst are taken from the literature. The performance of the reactors is investigated for two different operation modes: conventional …

Bicycle Cordon Count Pilot Study, Lisa Aultman-Hall

Kentucky Transportation Center Research Report

The Kentucky State Bicycle Coordinator is tasked with a difficult problem: planning for and supporting the needs of Kentucky cyclists. Unfortunately, very little quantitative information on the number of cyclists or their travel patterns has been collected in Kentucky. There is a pressing need to develop an efficient and low cost means to collect broad and useful data to support the bicycle program in Kentucky. Although some other jurisdictions include bicycles as vehicles in their traffic counting programs, Kentucky does not. Several complications make counting bicycles difficult: they cannot easily be detected by automatic counting devices, they travel in different …

Ultrasonic Enhancement Of Antibiotic Action On Escherichia Coli Biofilms: An In Vivo Model, Andrea M. Rediske, Beverly L. Roeder, Maren K. Brown, Jared L. Nelson, Rachel L. Robison, David O. Draper, G. Bruce Schaalje, Richard A. Robison, William G. Pitt

Faculty Publications

Biofilm infections are a common complication of prosthetic devices in humans. Previous in vitro research has determined that low-frequency ultrasound combined with aminoglycoside antibiotics is an effective method of killing biofilms. We report the development of an in vivo model to determine if ultrasound enhances antibiotic action. Two 24-h-old Escherichia coli (ATCC 10798) biofilms grown on polyethylene disks were implanted subcutaneously on the backs of New Zealand White female rabbits, one on each side of the spine. Low-frequency (28.48-kHz) and low-power-density (100- and 300-mW/cm2) continuous ultrasound treatment was applied for 24 h with and without systemic administration of gentamicin. The …

Postlaunch Sensor Verification And Calibration Of The Nasa Scatterometer, David G. Long, Wu-Yang Tsai, James E. Graf, Carroll Winn, James N. Huddleston, R. Scott Dunbar, Michael H. Freilich, Frank J. Wentz, W. Linwood Jones

Faculty Publications

Scatterometer instruments are active microwave sensors that transmit a series of microwave pulses and measure the returned echo power to determine the normalized radar backscattering cross section (sigma-0) of the ocean surface from which the speed and direction of near-surface ocean winds are derived. The NASA Scatterometer (NSCAT) was launched on board the ADEOS spacecraft in August 1996 and returned ten months of high-quality data before the failure of the ADEOS spacecraft terminated the data stream in June 1997. The purpose of this paper is to provide an overview of the NSCAT instrument and sigma-0 computation and to describe the …

Solving An Inverse Control Problem Using Predictive Methods, Chad J. Davis

Theses and Dissertations

Model Predictive Control is the class of control methods that optimizes a specified performance index in order to minimize the weighted future output deviations from a setpoint trajectory. This thesis applies MPC in the inverse sense -- known aircraft outputs are applied in the performance index as setpoints in an attempt to determine what control histories caused those outputs. Using this method, aircraft mishap investigators could then have a means of determining what the control surface deflections were throughout an incident since Flight Data Recorder data does not include control surface deflections. The actual Flight Data Recorder data from aircraft …

Close Formation Flight Control, Andrew W. Proud

Theses and Dissertations

In this research the close formation flight control problem is addressed. The formation consists of a lead and wing aircraft, where the wing flies in close formation with the lead, such that the lead's vortices produce aerodynamic coupling effects, and a reduction in the formation's drag is achieved. A controller, i.e., a formation-hold autopilot for the wing aircraft, is designed such that the formation's geometry is maintained in the face of lead aircraft maneuvers. In the formation flight control system, the wing and lead aircraft dynamics are coupled due to kinematic effects, and, in the case of close formations, additional …

Positive Anisotropic Group Scattering Cross Sections For Radiation Transport, J. Mark Delgrande

Theses and Dissertations

In solving the Boltzmann transport equation, most discrete ordinates codes calculate the source term by first approximating the scattering cross section using a Legendre polynomial expansion. Such expansions are insufficient when scattering is anisotropic and the Legendre expansion is truncated prematurely. This can lead to nonphysical negative cross sections, negative source terms and negative angular fluxes. While negative sources are problematic for standard discrete ordinates methods leading to poor convergence or convergence to incorrect results, they are of particular concern to exponential methods, causing such calculations to fail. We've developed and tested a new technique to solve this problem called …

Cryosphere Applications Of Nscat Data, David G. Long, Mark R. Drinkwater

Faculty Publications

Though designed to measure vector winds over the ocean, new imaging techniques facilitate the use of NASA scatterometer data (NSCAT) in cryosphere studies. NSCAT provides data of unprecedented coverage, resolution, and quality which, when coupled with the scatterometer image reconstruction with filtering (SIRF) algorithm, enables images of O at resolutions approaching 8 km over stationary targets. Such images are useful in ice mapping and classification, and multidecadal studies are possible by comparison with Seasat Scatterometer (SASS) data. The utility of NSCAT data in polar ice studies is illustrated through a review of two cryosphere applications of NSCAT data: (1) sea-ice …

Structural Disorder And The Origin Of High-Tc Suppression In La1.875ba0.125cuo4−Δ, Daniel Haskins, Edward A. Sterns, Fatih Dogan, Arnie R. Moodenbaugh

Materials Science and Engineering Faculty Research & Creative Works

Polarized x-ray absorption fine structure (XAFS) measurements at all La, Ba and Cu sites were used to study local structural features that accompany the strong T_c suppression at x ~ 1/8 in La_2-xBa_xCuO₄. Two critical parameters regulating the strength of hole-lattice coupling in this material were determined, i.e., the di- rection and magnitude of CuO₆ octahedra local tilts. Our findings include the existence of large disorder in the magnitude of the tilt angle about its average value < 0>, with a rms (formula presented) ≈2< 0>. We suggest that this large disorder strongly …

Truck Route Access Evaluation: Logan Aluminum Russellville - Logan County, Site #2657, David Cain, Kenneth R. Agent, Brian Aldridge, Lisa Aultman-Hall, Nikiforos Stamatiadis, Joel M. Weber

Kentucky Transportation Center Research Report

The Freight Movement and Intermodal Access in Kentucky Study (SPR 98-189) is being conducted by the Kentucky Transportation Center on behalf of the Kentucky Transportation Cabinet. There are two main objectives of the study: 1) evaluation of the access for trucks between intermodal or other truck generating sites and the National Highway System (NHS) and 2) furthering the understanding of freight commodity flows throughout the state. This report summarizes the access evaluation for a facility located in Logan County in the Barren River Development District (ADD) and KYTC Highway District# 3. The location of the site is shown in Figure …

Fdtd Modeling Of Emi Antennas, Motoshi Tanaka, Wei Cui, Xiao Luo, James L. Drewniak, Todd H. Hubing, Thomas Van Doren, Richard E. Dubroff

Electrical and Computer Engineering Faculty Research & Creative Works

The FDTD (finite-difference time-domain) method is used for modeling EMI antenna geometries to anticipate EMI problems in high-speed digital designs. FDTD is well-suited to modeling large-scale geometries such as cables that might be driven against PCB ground planes as a result of a noise voltage that appears at the connector. Three specific cases are addressed herein including a simple cable driven against a PCB ground, coupling between a high-speed digital and I/O line that drives a cable against the PCB, and the finite impedance of the PCB reference plane that results in an effective noise source that drives the PCB …

Integrating Research Results Into A Power Engineering Curriculum, Chanan Singh, Kraig J. Olejniczak, Kevin Tomsovic, Richard D. Christie, Anil Pahwa, Kwang Y. Lee, Mariesa Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents summaries of the activities of six research active power engineering educators which were presented in a panel session of the same name at the IEEE Power Engineering Society Winter Meeting on February 3, 1997 in New York City, USA. Each of the panelists discusses how research results are incorporated into courses and how students benefit from this approach.

The Effects Of Offshore Mining Of Beach Quality Sediments On Nearshore Wave Climate, Frank R. Lonza

Civil & Environmental Engineering Theses & Dissertations

Coastal communities rely on the beaches to attract tourism, but these sources of revenue require maintenance, such as beach nourishment. In an effort to maintain these beaches without causing any detrimental results, research is conducted to determine what effects, if any, exist when mining for sand in offshore areas.

The U.S. Government is permitting the search for beach quality sands offshore but is also ensuring that such mining will not have adverse results to the nearshore wave climate. This study was conducted using a coarse grid bathymetric map to calibrate a numerical model developed by the Danish Hydraulic Institute (DHI). …

Two Approaches To Critical Path Scheduling For A Heterogeneous Environment, Guangxia Liu

Computer Science Theses & Dissertations

Advances in computing and networking technologies are making large scale distributed heterogeneous computing a reality. Multi-Disciplinary Optimization (MDO) is a class of applications that is being addressed under this paradigm. It consists of multiple heterogeneous modules interacting with each other to solve an overall design problem. An efficient implementation of such an application requires scheduling heterogeneous modules (with different computing and disk 1/0 requirements) on a heterogeneous set of resources (with different CPU, memory, disk IO specifications).

Given a set of tasks and a set of resources, an optimal schedule of the tasks on the resources is very hard to …

Performance Optimization And Light-Beam-Deviation Analysis Of The Parallel-Slab Division-Of-Amplitude Photopolarimeter, Aed M. El-Saba, Rasheed M.A. Azzam, Mustafa A. G. Abushagur

Electrical Engineering Faculty Publications

A division-of-amplitude photopolarimeter that uses a parallel-slab multiple-reflection beam splitter was described recently [Opt. Lett. 21, 1709 (1996)]. We provide a general analysis and an optimization of a specific design that uses a fused-silica slab that is uniformly coated with a transparent thin film of ZnS on the front surface and with an opaque Ag or Au reflecting layer on the back. Multiple internal reflections within the slab give rise to a set of parallel, equispaced, reflected beams numbered 0, 1, 2, and 3 that are intercepted by photodetectors D₀, D₁, D₂, and D …

A Worst-Case Analysis Of Direct-Sequence Spread-Spectrum In Multipath Channels, Murad Hizlan, Xuedong Liu

Electrical and Computer Engineering Faculty Publications

We consider a direct-sequence spread-spectrum system operating in an indoors environment in the presence of multiaccess and multipath interference, and additive white Gaussian noise. We focus on the worst-case bit error probability of this system with a constraint on signal-to-interference ratio, and derive a Chernoff-type upper bound on this error probability. We evaluate the upper bound for a special case in order to gain understanding of the basic worst-case performance. We also compare the effects of the worst-case multipath interference with those of the worst-case multiuser interference of …

Low-Temperature Molecular Beam Epitaxy Of Gaas: A Theoretical Investigation Of Antisite Incorporation And Reflection High-Energy Diffraction Oscillations, K. Natarajan, Rama Venkat, Donald L. Dorsey

Electrical & Computer Engineering Faculty Research

Surface dynamics dominate the incorporation of charged, As+Ga, and neutral, As0Ga, antisite arsenic, and the temporal variation of reflection high-energy electron diffraction(RHEED) intensity in the low-temperature molecular beam epitaxy of (100) gallium arsenide(GaAs). A rate equation model is proposed which includes the presence and dynamics of a physisorbed arsenic (PA) layer riding the growth surface. The PA layer dictates the incorporation and concentration of As+Ga and As0Ga. Additionally, it influences the RHEED oscillations (ROs) behavior and the RO’s dependence on its coverage through its contribution to the reflected intensity. The model results for the dependence of As+Ga and As0Ga concentrations …

Impact Of Aggregate Fines On Short Term Properties Of Concrete Incorporating Water-Reducing Admixtures, Maged Maher Fakhry

Archived Theses and Dissertations

No abstract provided.

The Probability Density Of Spectral Estimates Based On Modified Periodogram Averages, David G. Long, Paul E. Johnson

Faculty Publications

Welch's (1967) method for spectral estimation of averaging modified periodograms has been widely used for decades. Because such an estimate relies on random data, the estimate is also a random variable with some probability density function. Here, the PDF of a power estimate is derived for an estimate based on an arbitrary number of frequency bins, overlapping data segments, amount of overlap, and type of data window, given a correlated Gaussian input sequence. The PDFs of several cases are plotted and found to be distinctly non-Gaussian (the asymptotic result of averaging frequency bins and/or data segments), using the Kullback-Leibler distance …

Why Does Ni Suppress Superconductivity In La1.85sr0.15cu1−Yniyo4?, Daniel Haskel, Edward A. Stern, V. Polinger, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

The role played by Ni impurities in destroying the superconducting state of La_2-xSr_xCuO₄ is still unclear. This is partly due to the lack of clear experimental evidence on the effect of Ni substitution upon the atomic and electronic structure of this cuprate. To provide this information, we performed Ni /(-edge polarized XAFS measure-ments on oriented powder. A special magnetic alignment geometry allowed us to measure pure ~ and aAb-polarized XAFS in identical experimental conditions. We found that the NiO6 octahedra are contracted along the t-axis by 0.16(A) relative to the CuO₆ octahedra in Lal.~sSro.~sCuO4, …

Truck Route Access Evaluation: Norfolk Southern Rail Terminal, Louisville, Site #1767, Lisa Aultman-Hall, Kenneth R. Agent, Brian Aldridge, David Cain, Nikiforos Stamatiadis, Joel M. Weber

Kentucky Transportation Center Research Report

This is a study undertaken on behalf of the Kentucky Transportation Cabinet (KYTC). There are two main objectives of the Freight Movement and Intermodal Access in Kentucky Study (SPR 98-189): evaluation of the access for trucks between intermodal or other truck generating sites and the National Highway System (NHS); and furthering the understanding of freight commodity flows throughout the state. This report summarizes the access evaluation for the Norfolk Southern Rail Intermodal Terminal located in Jefferson County in the KIPDA Area Development District (ADD) and KYTC Highway District #5. The location of the site is shown in Figure 1. Work …

Truck Route Access Evaluation: Campbell-Hausfeld, Leitchfield-Grayson County, Site #2637, David Cain, Kenneth R. Agent, Brian Aldridge, Lisa Aultman-Hall, Nikiforos Stamatiadis, Joel M. Weber

Kentucky Transportation Center Research Report

The Freight Movement and Intermodal Access in Kentucky Study (SPR 98-189) is being conducted by the Kentucky Transportation Center on behalf of the Kentucky Transportation Cabinet. There are two main objectives of the study: 1) evaluation of the access for trucks between intermodal or other truck generating sites and the National Highway System (NHS) and 2) furthering the understanding of freight commodity flows throughout the state. This report summarizes the access evaluation for the Campbell-Hausfeld Company facility located in Grayson County in the Lincoln Trail Area Development District (ADD) and KYTC Highway District #4. The location of the site is …