Engineering Commons^™

Surface Acoustic Wave Resonator Parameter Extraction And Oscillator Design, Mark Stephen Cavin

Retrospective Theses and Dissertations

Surface Acoustic Wave (SAW) resonators are frequently used in UHF oscillator designs. SAW resonators are available in the 100 MHz - 1 GHz frequency range which eliminates the need for frequency multiplication necessary with Bulk Acoustic Wave (BAW) devices. As operating frequencies increase, circuit parasitics play a larger role in device performance. One important source of parasitics is the device package and associated interconnects. To model a SAW resonator effectively, these parasitics need to be taken into account Resonator device models and their associated S-parameters can then be used in the design of oscillators. This thesis will discuss the design …

A Corrected Mixture Law For B/A, E. Carr Everbach, Z. Zhu, P. Jiang, B. T. Chu, R. E. Apfel

Engineering Faculty Works

A derivation is presented that corrects an expression for the effective acoustic nonlinearity parameter of a mixture of immiscible liquids. The derivation is based upon a mass fraction, rather than volume fraction, formulation.

A Stratified Air Model For Simulation Of Attic Thermal Performance, Florida Solar Energy Center, Danny Parker

FSEC Energy Research Center®

An improved computer simulation model for attics has been developed. The model accounts for detailed radiation, buoyancy and wind driven air flows and thermal stratification within the attic airspace. Through comparison with measured data, the paper examines the relative importance of the various modeling parameters and assumptions upon simulation accuracy. Stratification of the attic air was found to be a critical modeling characteristic which is typically ignored in building energy simulations. Both model and measurement results shows that air stratification increases significantly when low-emittance surfaces are included.

Impacts Of Duct Leakage On Infiltration Rates, Space Conditioning Energy Use, And Peak Electrical Demand In Florida Homes, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Testing for duct leakage was done in 91 homes. Tracer gas tests found that infiltration rates were four times greater when the air handler was operating than when it was off. Return leaks were found to average 10.0% of air handler total flow. House airtightness, in 63 of these homes, determined by blower door testing, averaged 12.38 air changes per hour at 50 Pascals (ACH50). When the duct registers were sealed, ACH50 decreased to 10.93, indicating that 11.7% of the house leaks were in the duct system.

Duct repairs were made on 25 homes. Blower door tests found 12.30 air …

Radiometer For The Investigation Of Infrared Emissions From Flames And Rocket Plumes, Kathy Underhill, M. Keith Hudson, Jason Willis, Mokhtar Mofidi, Matthew J. Russo

Journal of the Arkansas Academy of Science

A prototypical radiometer using standard one inch interference filters and a lead selenide detector was constructed for use in flame and rocket plume studies. This radiometer was designed to employ a 600 Hz chopper and chopper frequency/phase reference circuit for signal processing. Bandpass filters centered for either 2.7 mum or 4.45 mum were placed in the optical path. The passed carbon dioxide or water vapor band energy irradiated the lead selenide detector, resulting in an output voltage. This signal was then fed into a dedicated synchronous detector. The signal was then recorded by a computer system equipped with an analog-to-digital …

Homogenous Functions In Thermodynamics, Stephen R. Addison

Journal of the Arkansas Academy of Science

No abstract provided.

Data Acquisition And Control Program For Chromatography, M. Keith Hudson, William G. Hood

Journal of the Arkansas Academy of Science

No abstract provided.

Intelligent Control Of A Robotic Arm Using Hierarchical Neural Network Systems, Xavier J. R. Avula, Luis C. Rabelo

Chemical and Biochemical Engineering Faculty Research & Creative Works

Two artificial neural network systems are considered in a hierarchical fashion to plan the trajectory and control of a robotic arm. At the higher level of the hierarchy the neural system consists of four networks: a restricted Coulomb energy network to delineate the robot arm workspace; two standard backpropagation (BP) networks for coordinates transformation; and a fourth network which also uses BP and participates in the trajectory planning by cooperating with other knowledge sources. The control emulation process which is developed using a second neural system at a lower hierarchical level provides the correct sequence of control actions. An example …

Bs News

Building Services Engineering

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

1991 Directory Of Indiana State, County, City And Town Officials Responsible For Road And Street Work, Herpicc

Indiana Local Technical Assistance Program (LTAP) Directory

Contact information for agency officials and employees responsible for Indiana’s local road infrastructure.

Endothelial Superoxide Production In The Isolated Rat Heart During Early Reperfusion After Ischemia -- A Histochemical Study, Charles F. Babbs, Meloney D. Cregor, John J. Turek, Stephen F. Badylak

Weldon School of Biomedical Engineering Faculty Publications

This paper describes a histochemical study of superoxide generation in buffer-perfused, isolated rat hearts during the first 2 minutes of reperfusion after 60 minutes of warm ischemia. Superoxide radical production was demonstrated by a modification of Karnovsky's manganese/diaminobenzidine technique, in which superoxide oxidizes Mn++ to Mn+++ ions, which in turn oxidize diaminobenzidine to form amber, osmiophilic polymers, observable by light or electron microscopy. Isolated hearts were rendered ischemic, reperfused with oxygen equilibrated buffer containing Mn++ and diaminobenzidine, fixed by perfusion with Trump's solution, and processed for light and electron microscopy. The method consistently demonstrated evidence of superoxide generation near the …

Methylene Blue As An Inhibitor Of Superoxide Generation By Xanthene Oxidase: A Potential New Drug For The Attenuation Of Ischemia/Reperfusion Injury, Steven C. Salaris, Charles F. Babbs, William D. Voorhees

Weldon School of Biomedical Engineering Faculty Publications

Tissue oxidases, especially xanthine oxidase, have been proposed as primary sources of toxic oxygen radicals in many experimental models of disease states. Among these, ischemia-reperfusion injury may be of the greatest clinical interest. In this paper we propose the use of methylene blue as a means of suppressing the production of superoxide radicals, O2, by acting as an alternative electron acceptor for xanthine oxidase. Previous work has indicated that methylene blue accepts electrons from xanthine oxidase at the iron-sulfur center. Initial experiments in our laboratory demonstrated that (1) pairs of electrons from each enzymatic oxidation are transferred to methylene blue, …

Effective Estimation And Computer Control Of Minimum Tumour Temperature During Conductive Interstitial Hyperthermia, J A. Deford, Charles F. Babbs, U H. Patel, M W. Bleyer, J A. Marchosky, C J. Moran

Weldon School of Biomedical Engineering Faculty Publications

The goal of heat therapy in the treatment of malignant disease is to raise the temperature of all neoplastic tissue to a cytotoxic temperature for a predetermined period of time. This seemingly simple task has proved difficult in-vivo, in part because of nonuniform power absorption and in part because of nonhomogeneous and time varying tumour blood flow. We have addressed this difficulty first by utilizing the conceptually simple technique of conductive interstitial hyperthermia, in which the tumour is warmed by multiple, electrically heated catheters, and second by implementing on-line conu·ol of minimum tumour temperatures near each catheter, estimated on the …

Design And Evaluation Of Closed-Loop Feedback Control Of Minimum Temperatures In Human Intracranial Tumors Treated With Interstitial Hyperthermia, J A. Deford, Charles F. Babbs, U H. Patel, N E. Fearnot, J A. Marchosky, C J. Moran

Weldon School of Biomedical Engineering Faculty Publications

The dynamic nature of blood flow during hyperthermia therapy has made the control of minimum tumor temperature a difficult task. This paper presents initial studies of a novel approach to closed-loop control of local minimum tissue temperatures utilizing a newly developed estimation algorithm for use with conductive interstitial heating systems. The local minimum tumor temperature is explicitly estimated from the power required to maintain each member of an array of electrically heated catheters at a known temperature, in conjunction with a new bioheat equation-based algorithm to predict the ‘droop’ or fractional decline in tissue temperature between heated catheters. A closed …

Experimental Determination Of The Effects Of Degenerate Fermi Statistics On Heavily P‐Doped Gaas, E. S. Harmon, Michael R. Melloch, Mark S. Lundstrom, Michael L. Lovejoy

Department of Electrical and Computer Engineering Faculty Publications

The effects of degenerate Fermi statistics on electron injection currents for p+‐GaAs grown by molecular beam epitaxy are presented. To achieve Be dopant concentrations of greater than 8×10¹⁹ cm⁻³, the substrate temperature during growth was reduced to approximately 450 °C from the usual 600 °C. In this heavily doped material, we measure unexpectedly large electron injectioncurrents which are interpreted in terms of an effective narrowing of the band gap. At extremely heavy doping densities, the Fermi level pushes into the valence band and degenerate Fermi statistics must be taken into account. For doping concentrations greater than …

Zero-Field Time-Of-Flight Measurements Of Electron Diffusion In P+-Gaas, Michael L. Lovejoy, B. M. Keyes, M. E. Klausmeier-Brown, Michael R. Melloch, R. K. Ahrenkiel, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

Minority electron diffusivities in p+-GaAs-doped NA =~1.4×10¹⁸ and ~10¹⁹ cm^-3 have been measured in zero-field conditions with an extension of the zero-field time-of-flight technique. Extension of the technique to make it applicable to heavily doped p+-GaAs is described and zero-field data are discussed. Unexpectedly, majority carrier drag effects are not evident in a comparison of this data with recently reported high-field data. Low zero-field mobility of electrons in p+-GaAs has important implications for high-speed devices such as heterojunction bipolar transistors.

Transistor-Based Studies Of Heavy Dop-Ing Effects In N-Gaas, M. P. Patkar, Mark S. Lundstrom, Michael R. Melloch

Department of Electrical and Computer Engineering Faculty Publications

The n2ieDp product (where n2ie is the np product and Dp is the minority hole mobility) in heavily doped n‐GaAs has been measured by electrical characterization of p‐n‐p GaAs homojunction transistors with base dopings ranging from approximately 1×1017 to 9×1018 cm−3. The measured n2ieDp product decreases as the doping density increases. These results suggest that nie is roughly constant with doping density, in sharp contrast to the large increase observed for p‐type GaAs. This work shows that when designing GaAs bipolar devices, …

Repair/Rehabilitation Of Deteriorated Drainage Pipe, Bob G. Mccullouch

JTRP Technical Reports

This report describes the current technologies, methods and materials used in drainage pipe rehab and replacement. It also identifies which of these technologies can be applied for the various pipe material types. Installed cost information was obtained from the states in the survey and from vendors for the various methods. In describing each method, equipment requirements and limitations are reported. From this report, one should be able to understand what method is appropriate for the various repair problems and pipe types.

Test 1338/2: Hurlimann 6135 Vdt Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.

Test 1645: Ford 4630 (8x2) Diesel 8-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Test 1647: Ford 8730 Powershift Diesel 18-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Test 1651: Case International 9250 Diesel And Steiger 9250 Diesel 12-Speeds, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Test 1652: Case International 9260 Diesel And Steiger 9260 Diesel 12-Speeds, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Test 1654: Caterpiller Challenger 75 And 75c Diesel 10-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Test 1655: Belarus 572, 505, 525 And 570 Diesel 18-Speeds, Nebraska Tractor Test Lab

Nebraska Tractor Tests

EXPLANATION OF THE TEST PROCEDURE General Tractors are tested at the University of Nebraska according to the Agricultural Tractor Test Code approved by the American Society of Agricultural Engineers and the Society of Automotive Engineers or official Nebraska test procedure. The manufacturer selects the tractor to be tested and certifies that it is a stock model. Each tractor is equipped with the common power consuming accessories such as power steering, power lift pump, generator, etc., if available. Power consuming accessories may be disconnected only when the means for disconnecting can be reached from the operating station. An official representative of …

Nebraska Summary: S104 Ford 4630 8x8, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S102 Ford 3430 8x8, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S101 John Deere 3255, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …

Nebraska Summary: S137 Zetor 9540, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data. EXPLANATION OF THE TEST PROCEDURES Purpose The purpose of …