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Articles 67711 - 67740 of 75074

Full-Text Articles in Engineering

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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.


User Guide For Pc-Stabl3d, Gennady Moshkovich Jan 1991

User Guide For Pc-Stabl3d, Gennady Moshkovich

JTRP Technical Reports

PC-STABL3D is the program for IBM PC compatible computers, developed to handle general stability analysis of three-dimensional slopes. Random generation routines are invoked to create trial failure surfaces, which are analyzed using the limiting equilibrium approach. The current version of PC-STABL3D is enhanced by a graphical pre/postprocessor, which facilitates creation and edition 0 data files, examination of problem geometry, and analyzing of the obtained failure surfaces. After the failure surfaces are generated and their factors of safety are computed, the program performs statistical analysis of received factors of safety, and calculates minimum statistical factor of safety. The information about minimum …


Use Of Waste Materials In Highway Construction, Imtiaz Ahmed Jan 1991

Use Of Waste Materials In Highway Construction, Imtiaz Ahmed

JTRP Technical Reports

This study synthesizes the information on the use of waste materials in highway construction. The information was obtained from a review of published literature supplemented by: recent unpublished reports, presentations of research updates by professionals at different forums, anti personal meetings with the experts. In addition, a questionnaire regarding the use of waste materials was prepared and distributed to each of the state highway agencies. A majority of states responded to the questionnaire, giving a summary of current practices in the use of waste materials in highway construction and their experiences on the technical, environmental, and economic aspects of the …


Traffic Speed Report No. 124: Traffic Report, David L. Cochran, Donald W. Genda Jan 1991

Traffic Speed Report No. 124: Traffic Report, David L. Cochran, Donald W. Genda

JTRP Technical Reports

No abstract provided.


Speed Trends On Indiana Rural Interstate Highways : Traffic Report, David L. Cochran Jan 1991

Speed Trends On Indiana Rural Interstate Highways : Traffic Report, David L. Cochran

JTRP Technical Reports

No abstract provided.


Test 1338/2: Hurlimann 6135 Vdt Diesel, Nebraska Tractor Test Lab Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 Jan 1991

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 …


Nebraska Summary: S338 Hurlimann 6135, Nebraska Tractor Test Lab Jan 1991

Nebraska Summary: S338 Hurlimann 6135, 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 …


Interim Report: Embankment Widening And Grade Raising On Soft Foundation Soils, Example I - Indiana State Route 55 Over Turkey Creek In Lake County, Indiana, Scott J. Ludlow, Wai-Fah Chen, Philippe L. Bourdeau, C. W. Lovell Jan 1991

Interim Report: Embankment Widening And Grade Raising On Soft Foundation Soils, Example I - Indiana State Route 55 Over Turkey Creek In Lake County, Indiana, Scott J. Ludlow, Wai-Fah Chen, Philippe L. Bourdeau, C. W. Lovell

JTRP Technical Reports

No abstract provided.


The Impact Of Highway Services And Expenditures On Regional Economic Development, Paulus Cornelius Lombard, Kumares C. Sinha, Deborah J. Brown Jan 1991

The Impact Of Highway Services And Expenditures On Regional Economic Development, Paulus Cornelius Lombard, Kumares C. Sinha, Deborah J. Brown

JTRP Technical Reports

This report presents results from a study to determine the relationship between highway infraatructure and economic development in Indiana. Regression models and a computer model were developed to estimate the annual long-term impacts of highway construction on economic growth. Results from an analysis of economic impacts of the construction of 13 four-lane highway sections in Indiana, as well as an analysis of national data concerning industrial location determinants, are also presented.


Engineering Soils Map Of Jay County, Indiana, Arvind Chaturvedi, Andrew Garrigus Jan 1991

Engineering Soils Map Of Jay County, Indiana, Arvind Chaturvedi, Andrew Garrigus

JTRP Technical Reports

The soils mapping of Jay County was done primarily by the analysis of landforms and associated parent materials as portrayed on stereoscopic aerial photographs. Valuable information for soils was obtained from publications of the Soil Conservation Service, United States Department of Agriculture. Test data from roadway and bridge projects was obtained from the Indiana Department of Transportation. Soil profiles for the landform/parent material areas mapped are presented on the engineering soils map, a copy of which is included at the end of the report.


Novel Chemical Preparative Route For Semiconducting Mose2 Thin Films, K. C. Mandal, O. Savadogo Jan 1991

Novel Chemical Preparative Route For Semiconducting Mose2 Thin Films, K. C. Mandal, O. Savadogo

Faculty Publications

No abstract provided.


User's Manual For The Software "Tfpi" That Implements The Traffic Forecasting Procedure For Indiana, Sunil K. Saha, Jon D. Fricker Jan 1991

User's Manual For The Software "Tfpi" That Implements The Traffic Forecasting Procedure For Indiana, Sunil K. Saha, Jon D. Fricker

JTRP Technical Reports

A program has been written in Microsoft QuickBASIC to implement the traffic models developed for both rural and urban Indiana state highway segments during a two-phase HPR Project carried out for the Indiana Department of Transportation. The report ''TRAFFIC VOLUME FORECASTING METHODS FOR RURAL STATE HIGHWAYS" describes the models developed in Phase 1 of the study, while the report "THE DEVELOPMENT OF A PROCEDURE TO FORECAST TRAFFIC VOLUMES ON URBAN SEGMENTS OF THE STATE AND INTERSTATE HIGHWAY SYSTEMS" describes the models developed in Phase 2. For rural interstates, new models have been developed in Phase 2 that supercede the Phase …


Bioconcentrations Of Heavy Metals Copper, Chromium (Tot), Lead, Zinc, Nickel And Mercury In The Missouri River 1991 Jan 1991

Bioconcentrations Of Heavy Metals Copper, Chromium (Tot), Lead, Zinc, Nickel And Mercury In The Missouri River 1991

United States Army Corps of Engineers, Omaha District

The presence of heavy metals within aquatic environments can be attributed to sources such as industry, municipal discharges, agriculture and natural processes which release various amounts into natural systems. Metals such as copper, zinc and chromium are listed as essential micronutrients for many plant and animal species. Of potential concern, however, is the tendency of heavy metals to accumulate within the food webs of ecosystems. Classified as biologically hard to degrade, heavy metals may concentrate to significant amounts within the trophic levels of a particular ecosystem. At these increased concentrations many of these heavy metals become toxic to living organisms. …