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Articles 68611 - 68640 of 75068

Full-Text Articles in Engineering

A General Ordinance Establishing Storm Drainage Control, Herpicc Jan 1988

A General Ordinance Establishing Storm Drainage Control, Herpicc

Indiana Local Technical Assistance Program (LTAP) Publications

The preparation of this model drainage ordinance was the result of numerous meetings by a committee composed of County Commissioners, County Engineers, County Surveyors, and representatives of the Indiana Department of Natural Resources, and Indiana Department of Highways. The goal of this group was to formulate a drainage ordinance that could be adapted by Indiana counties to satisfy the counties' needs for reasonable drainage control, the current state of engineering practice and reasonable engineering standards. The group began with the experience of counties in Indiana which had already adopted some form of drainage control policy. Through numerous modifications and additions, …

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Roller Compacted Concrete For Highway Applications, Jorge Gomez-Dominguez Jan 1988

Roller Compacted Concrete For Highway Applications, Jorge Gomez-Dominguez

Indiana Local Technical Assistance Program (LTAP) Publications

A series of laboratory studies were carried out to investigate the behavior and characteristics of Roller Compacted Concrete (RCC) for highway applications.

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A Rapid, Widely Applicable Screen For Drugs That Suppress Free Radical Formation In Ischemia/Reperfusion, Steven C. Salaris, Charles F. Babbs Jan 1988

A Rapid, Widely Applicable Screen For Drugs That Suppress Free Radical Formation In Ischemia/Reperfusion, Steven C. Salaris, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Substantial injury can occur during reoxygenation of previously ischemic tissue in many experimental models, as the result of the generation of oxygen-derived free radicals. To test the antiradical activity of potentially protective compounds in this setting, we developed a simple screening system, applicable to fresh biopsy specimens, in which warm ischemia and reoxygenation of excised tissue are performed in vitro. Tissue production of malondialdehyde (MDA) equivalents is used as a nonspecific-but-sensitive marker of oxygen radical damage. Test compounds with putative antiradical activity are added prior to the reoxygenation phase, and their ability to suppress MDA production is an index of …

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A Rapid, Widely Applicable Screen For Drugs That Suppress Free Radical Formation In Ischemia/Reperfusion, Steven C. Salaris, Charles F. Babbs Jan 1988

A Rapid, Widely Applicable Screen For Drugs That Suppress Free Radical Formation In Ischemia/Reperfusion, Steven C. Salaris, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Substantial injury can occur during reoxygenation of previously ischemic tissue in many experimental models, as the result of the generation of oxygen-derived free radicals. To test the antiradical activity of potentially protective compounds in this setting, we developed a simple screening system, applicable to fresh biopsy specimens, in which warm ischemia and reoxygenation of excised tissue are performed in vitro. Tissue production of malondialdehyde (MDA) equivalents is used as a nonspecific-but-sensitive marker of oxygen radical damage. Test compounds with putative antiradical activity are added prior to the reoxygenation phase, and their ability to suppress MDA production is an index of …

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Evidence For Band-Gap Narrowing Effects In Be-Doped, P-P+ Gaas Homojunction Barriers, H. L. Chuang, Paul David Demoulin, M. E. Klausmeier-Brown, Michael R. Melloch, Mark S. Lundstrom Jan 1988

Evidence For Band-Gap Narrowing Effects In Be-Doped, P-P+ Gaas Homojunction Barriers, H. L. Chuang, Paul David Demoulin, M. E. Klausmeier-Brown, Michael R. Melloch, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

The electrical performance of Be‐doped, p‐p+ GaAs homojunction barriers is characterized and analyzed. The results of the analysis show that minority‐carrier electrons, at 300 K, have a mobility of 4760 cm2/V s at a hole concentration of 2.3×1016 cm−3, and that the effective recombination velocity for these homojunction barriers is about 6×104 cm/s. We present evidence that this unexpectedly high recombination velocity is a consequence of an effective reduction in band gap due to the heavy impurity doping. The effective band‐gap shrinkage in this Be‐doped material grown by molecular‐beam epitaxy appears to be comparable to that already …

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Effects Of Heavy Impurity Doping On Electron Injection In P+-N Gaas Diodes, M. E. Klausmeier-Brown, Mark S. Lundstrom, Michael R. Melloch, S. P. Tobin Jan 1988

Effects Of Heavy Impurity Doping On Electron Injection In P+-N Gaas Diodes, M. E. Klausmeier-Brown, Mark S. Lundstrom, Michael R. Melloch, S. P. Tobin

Department of Electrical and Computer Engineering Faculty Publications

Measurements of electron injection currents in p+‐n diodes are presented for a range of p‐type dopant concentrations. A successive etch technique was used to characterize the electron injection current in terms of the product (noDn). Measurements are presented for Zn‐doped GaAs solar cells with p‐layer hole concentrations in the range 6.3×1017−1.3×1019 cm−3. The results demonstrate that so‐called band‐gap narrowing effects substantially increase the injected electron current in heavily doped p‐type GaAs. These heavy doping effects must be accounted for in the modeling and design of GaAs solar cells and heterostructure …

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Myocardial Perfusion Pressure: A Predictor Of 24hour Survival During Prolonged Cardiac Arrest In Dogs, Karl B. Kern, Gordon A. Ewy, William D. Voorhees, Charles F. Babbs, Willis A. Tacker Jan 1988

Myocardial Perfusion Pressure: A Predictor Of 24hour Survival During Prolonged Cardiac Arrest In Dogs, Karl B. Kern, Gordon A. Ewy, William D. Voorhees, Charles F. Babbs, Willis A. Tacker

Weldon School of Biomedical Engineering Faculty Publications

Myocardial perfusion pressure, defined as the aortic diastolic pressure minus the right atria1 diastolic pressure, correlates with coronary blood flow during cardiopulmonary resuscitation (CPR) and predicts initial resuscitation success. Whether this hemodynamic parameter can predict 24-h survival is not known. We examined the relationship between myocardial perfusion pressure and 24-h survival in 60 dogs that underwent prolonged (20 min) ventricular fibrillation and CPR. Forty-two (70%) animals were initially resuscitated and 20 (33%) survived for 24 h. Myocardial perfusion pressure was significantly greater when measured at 5, 10, 15 and 20 min of ventricular fibrillation in the resuscitated animals than in …

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Fly Ash Concrete For Highway Use : Executive Summary, Sidney Diamond, J. Olek Jan 1988

Fly Ash Concrete For Highway Use : Executive Summary, Sidney Diamond, J. Olek

JTRP Technical Reports

No abstract provided.

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Nebraska Summary: S048 John Deere 2155, Nebraska Tractor Test Lab Jan 1988

Nebraska Summary: S048 John Deere 2155, 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 …

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Nebraska Summary: S031 Massey Ferguson 375, Nebraska Tractor Test Lab Jan 1988

Nebraska Summary: S031 Massey Ferguson 375, 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 …

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Layer Coefficients In Terms Of Performance And Mixture Characteristics, Brian David Coree, Thomas D. White Jan 1988

Layer Coefficients In Terms Of Performance And Mixture Characteristics, Brian David Coree, Thomas D. White

JTRP Technical Reports

No abstract provided.

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Electrochemical Production And Corrosion Testing Of Amorphous Ni-P, Jose L. Carbajal, Ralph E. White Jan 1988

Electrochemical Production And Corrosion Testing Of Amorphous Ni-P, Jose L. Carbajal, Ralph E. White

Faculty Publications

Ni-P alloys were prepared by electrodeposition under different conditions on a rotating disk electrode. A variety of alloys were prepared ranging from Ni-15P to Ni-25P. An indirect reduction of species in solution involving several steps appears to be favored over the direct reduction at the electrode based on the low P content in the alloy. Energy dispersion x-ray microanalysis was used to determine composition of the alloy. Transmission electron microscopy and x-ray diffraction corroborated the amorphous nature of the structure. The physical and chemical homogeneity of the metallic glasses produced electrochemically is substantiated by the absence of electrochemical localized attack. …

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Monitoring Natural Air Corn Drying—A Demonstration Project, Richard O. Pierce, Gary L. Zoubek Jan 1988

Monitoring Natural Air Corn Drying—A Demonstration Project, Richard O. Pierce, Gary L. Zoubek

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A demonstration project is described where natural air corn drying performance was monitored weekly and drying results were printed in a local newspaper. The newspaper articles also gave management recommendations for the upcoming week. Similar demonstration projects can be conducted using the procedures described in this paper.

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Correlation Of Starch Recovery With Assorted Quality Factors Of Four Corn Hybrids, Curtis L. Weller, Marvin R. Paulsen, Marvin P. Steinberg Jan 1988

Correlation Of Starch Recovery With Assorted Quality Factors Of Four Corn Hybrids, Curtis L. Weller, Marvin R. Paulsen, Marvin P. Steinberg

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A laboratory wet-milling process was developed for use in determining starch recovery of yellow dent corn. The effects of harvest moisture and drying air temperature on starch recovery were investigated for four hybrids. A split split-plot experimental design was used to evaluate the effects. Starch recovery was not significantly different among the hybrids; however, it did decreases both harvest moisture and drying air temperature increased. Starch recovery was correlated with quantitative measures of assorted quality factors. Regression analysis found starch recovery to be a function of starch content, test weight, and ethanol-soluble protein.

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Calibration Accuracy Of Pesticide Application Equipment, Robert Grisso, E. J. Hewett, Elbert C. Dickey, R. D. Schnieder, E. W. Nelson Jan 1988

Calibration Accuracy Of Pesticide Application Equipment, Robert Grisso, E. J. Hewett, Elbert C. Dickey, R. D. Schnieder, E. W. Nelson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Afield survey of 140 private and commercial pesticide applicators was conducted during the spring of 1986 in 12 counties of central and eastern Nebraska. The results showed that one out of every three cooperators was applying pesticides within ± 5% of their intended application rate. Results indicated that applicators have reduced application errors from that of a similar survey conducted in 1979. However, most errors still can be traced to incorrect calibration. Ninety-four percent of the cooperators used some type of calibration method. Two-thirds used the "Known Area" method. Those using a calibration method more than once a year had …

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Surface Cover From Corn Residue On Sandy Soils, R. Todd, Norman L. Klocke, Elbert C. Dickey, Dennis Bauer Jan 1988

Surface Cover From Corn Residue On Sandy Soils, R. Todd, Norman L. Klocke, Elbert C. Dickey, Dennis Bauer

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Corn residue left as surface cover after land preparation and planting by various combinations of tillage implements and surface planters, respectively, was measured on four research/ demonstration sites with sandy soils in Nebraska. Surface cover ranged from 51 to 80% for the no-till treatments to 14 to 53% for the twice-disked treatments. The wide range in cover was due to the amount of antecedent residues from the previous crop and the soil type which ranged from sandy loam to tine sands. Other tillage implements included a rolling cultivator, sweep-plow, and mulch-treader.

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Can We Guarantee The Safety Of Genetically Engineered Organisms In The Environment?, Kathleen H. Keeler, Frances E. Sharples Jan 1988

Can We Guarantee The Safety Of Genetically Engineered Organisms In The Environment?, Kathleen H. Keeler, Frances E. Sharples

School of Biological Sciences: Faculty Publications

Can we guarantee the safety of genetically engineered organisms in the environment? To anticipate my remarks, the answer to the title question is “No, we cannot guarantee the safety of genetically engineered organisms released into the environment.” Indeed, it is a tenet of the scientific method that nothing can be proved, only disproved. Thus, we can never show that a release will be safe. We could only show that it would be unsafe, if that were the case. However, if the question is posed differently, for example, can we safely release genetically engineered organisms into the environment?, the answer is …

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Oxygen Reduction On Silver In 6.5 Molar Caustic Soda Solution, Prosper K. Adanuvor, Ralph E. White Jan 1988

Oxygen Reduction On Silver In 6.5 Molar Caustic Soda Solution, Prosper K. Adanuvor, Ralph E. White

Faculty Publications

No abstract provided.

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A Two-Dimensional Mathematical Model Of A Porous Lead Dioxide Electrode In A Lead-Acid Cell, E. C. Dimpault-Darcy, T. V. Nguyen, Ralph E. White Jan 1988

A Two-Dimensional Mathematical Model Of A Porous Lead Dioxide Electrode In A Lead-Acid Cell, E. C. Dimpault-Darcy, T. V. Nguyen, Ralph E. White

Faculty Publications

A two-dimensional mathematical model is presented for a lead dioxide electrode in a lead-acid cell. It is used to simulate the time dependent behavior of the electrode during discharge. The model contains six dependent variables: the concentration of the acid electrolyte, the porosity, the electrical potentials of the solid and solution phases, and the two directional components of the current density in the electrolyte. The effect of the electrode grid was included by varying the conductivity of the solid. Parameters such as electrode conductivity, electrode dimensions, and temperature are investigated to understand their effects on electrode discharge performance.

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Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White Jan 1988

Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White

Faculty Publications

Secondary current density distributions are of interest
to cell designers. The purpose of this note is to illustrate
how to use an existing numerical method to determine
these distributions for cells that contain conducting and
nonconducting bodies between the main anode and cathode.

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Analysis Of Electrokinetic Data By Parameter Estimation And Model Discrimination Techniques, Prosper K. Adanuvor, Ralph E. White Jan 1988

Analysis Of Electrokinetic Data By Parameter Estimation And Model Discrimination Techniques, Prosper K. Adanuvor, Ralph E. White

Faculty Publications

An alternative approach to classical methods of electrochemical data analysis is presented. This alternative method is based on nonlinear parameter estimation and model discrimination techniques. The method is used to obtain the relevant kinetic and transport parameters and to elucidate the kinetic mechanism of O2 reduction at carbon and silver electrodes in alkaline electrolytes.

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A Mathematical Model For Predicting Cyclic Voltammograms Of Electronically Conductive Polypyrrole, Taewhan Yeu, Trung V. Nguyen, Ralph E. White Jan 1988

A Mathematical Model For Predicting Cyclic Voltammograms Of Electronically Conductive Polypyrrole, Taewhan Yeu, Trung V. Nguyen, Ralph E. White

Faculty Publications

Polypyrrole is an attractive polymer for use as a high energy density secondary battery because of its potential as an inexpensive, lightweight, and noncorrosive electrode material. A mathematical model to simulate cyclic voltammograms for polypyrrole is presented here. The model is for a conductive porous electrode film on a rotating disk electrode (RDE) and is used to predict the spatial and time dependence of concentration, overpotential, and stored charge profiles within a polypyrrole film. The model includes both faradaic and capacitive charge components in the total current density expression.

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Predicting Shunt Currents In Stacks Of Bipolar Plate Cells With Conducting Manifolds, H. S. Burney, Ralph E. White Jan 1988

Predicting Shunt Currents In Stacks Of Bipolar Plate Cells With Conducting Manifolds, H. S. Burney, Ralph E. White

Faculty Publications

A method is presented for predicting shunt currents in stacks of bipolar plate cells with conducting manifolds. The method is based on the requirement that the potential drop through the solution in a manifold be large enough to force current to leave the solution and to enter the conducting manifold. The current that leaves the solution in the manifold enters the conducting manifold at the anode end of the stack and returns to the solution at the cathode end. This could cause catastrophic failure of a manifold.

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Oxygen Reduction On Silver In 6.5m Caustic Soda Solution, Prosper K. Adanuvor, Ralph E. White Jan 1988

Oxygen Reduction On Silver In 6.5m Caustic Soda Solution, Prosper K. Adanuvor, Ralph E. White

Faculty Publications

The cathodic reduction of oxygen in 6.5M membrane-grade caustic soda solution has been studied experimentally at a silver rotating disk electrode at 25°C. The results can be approximated by the parallel mechanism for oxygen reduction with catalytic decomposition of peroxide. Further analysis of this mechanism indicates that the sequential process with catalytic decomposition of peroxide predominates over the direct 4e– process. Direct application of the sequential mechanism to the data indicates that the latter mechanism with catalytic decomposition of peroxide much more accurately reflects the experimental results. The relevant kinetic parameters are calculated on the basis of …

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A Mathematical Model For The Electrodeposition Of Alloys On A Rotating Disk Electrode, Shiuan Chen, Ken-Ming Yin, Ralph E. White Jan 1988

A Mathematical Model For The Electrodeposition Of Alloys On A Rotating Disk Electrode, Shiuan Chen, Ken-Ming Yin, Ralph E. White

Faculty Publications

A general multiple electrode reaction model for electrodeposition of alloys on a rotating disk electrode is presented. Included in the model are mass transport equations with the effect of ionic migration, Butler-Volmer kinetic rate expressions, and the mole fractions of the individual components in the solid state. The model shows that the effect of ionic migration is important and that plating variables such as applied potential, pH, and bulk concentration can be included. Two examples (Ni-P and Ru-Ni-P) are used to illustrate the predictions of the model.

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Electrodeposition Of Copper-Nickel Alloys From Citrate Solutions On A Rotating Disk Electrode, Ramona Y. Ying, Patrick K. Ng, Z. Mao, Ralph E. White Jan 1988

Electrodeposition Of Copper-Nickel Alloys From Citrate Solutions On A Rotating Disk Electrode, Ramona Y. Ying, Patrick K. Ng, Z. Mao, Ralph E. White

Faculty Publications

A mathematical model is developed to simulate the electrodeposition of Cu-Ni alloy from citrate solutions onto a rotating disk electrode under potentiostatic control. The model includes the influence of diffusion, ionic migration, forced convection, and homogeneous equilibria. The three major electrochemical reactions treated in the model are copper deposition, nickel deposition, and hydrogen evolution. Using experimental parameters when available, the model was fitted and tested against experimentally-obtained results for different bath compositions and operating conditions. The model agreed reasonably well with the experimental results particularly in the codeposition region, –1.0 to –1.2V vs. SCE, where hydrogen evolution is not the …

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Human Health Effects Assays, Ronald C. Sims, J. L. Sims, R. R. Dupont Jan 1988

Human Health Effects Assays, Ronald C. Sims, J. L. Sims, R. R. Dupont

Biological Engineering Faculty Publications

Environmental health risk assessments based upon animal study results, epidemiology, quantitative structure activity relationships (QSARs), dose-response relationships, risk perception, and expert systems approaches, and the evaluation of mechanisms of carcinogenesis represent the focus for 1987. The term "biological risk assessment" was discussed by Clayson1 to describe that part of risk assessment concerned with the relevance of specific animal results to the induction of human cancer. Guidelines for health assessment of suspect developmental toxicants addressed evaluation of data from animal testing studies.2 Animal toxicity data on 200 chemicals and epidemiologic data on 30 chemicals was included within a data …

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Biological Transformation And Detoxification Of 7,12-Dimethylbenzanthracene In Soil, K. Park, Ronald C. Sims, W. J. Doucette, J. E. Matthews Jan 1988

Biological Transformation And Detoxification Of 7,12-Dimethylbenzanthracene In Soil, K. Park, Ronald C. Sims, W. J. Doucette, J. E. Matthews

Biological Engineering Faculty Publications

Biological transformation and detoxification of 7,12-dimethylbenz(a)anathracene (DMBA) were studied in a nonacclimated sandy loam soil. Parent 14C DMBA biodegraded extensively (62% to 20%), accompanying an increase of metabolite 14C fraction (4% to 53%). Incorporation of DMBA into non extractable soil residue ,4C increased from 12 to 17%, but the increase was not statistically significant. DMBA was transformed into several metabolic products in the soil system, including 4-hydroxy-, 5-hydroxy-, and 10-hydroxy-DMBA and 7,12-dihydro 12-methyl-7-methylene-benz(a)anthracene-12-ol. High polarity transformation products of DMBA demonstrated a negative mu tagenic response with the Ames mutagenicity assay, strain TA 100, for both low and neutral pH soils. …

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Fate And Transport Of Organics In Soil: Model Predictions And Experimental Results, B. D. Symons, Ronald C. Sims, W. J. Grenney Jan 1988

Fate And Transport Of Organics In Soil: Model Predictions And Experimental Results, B. D. Symons, Ronald C. Sims, W. J. Grenney

Biological Engineering Faculty Publications

Laboratory batch reactors were used to generate quantitative information about the fate of polynuclear aromatic hydrocarbon (PNA) compounds in soil systems. First-order degradation rates and equilibrium partition coefficients determined in laboratory studies were used in the Vadose Zone Interactive Processes (VIP) mathematical model to predict the fate and behavior of the PNA compounds as a function of time and soil depth. Predicted model results were compared with independent laboratory soil column studies for model validation. The VIP model provided a good approximation of the degradation and transport of the seven PNA compounds evaluated after 6 months of incubation in soil. …

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Great Salt Lake Interisland Diking: Water Quality Considerations, Executive Summary, Utah Water Research Laboratory, J. P. Riley, J. I. Blandamer, W. J. Doucette, R. R. Dupont, A. W. Grover, J. Herrick, J. M. Ihnat, J. E. Mclean, M. W. Nath, S. R. Rushforth, J. L. Sims, R. C. Sims, W. A. Wurtsbaugh Jan 1988

Great Salt Lake Interisland Diking: Water Quality Considerations, Executive Summary, Utah Water Research Laboratory, J. P. Riley, J. I. Blandamer, W. J. Doucette, R. R. Dupont, A. W. Grover, J. Herrick, J. M. Ihnat, J. E. Mclean, M. W. Nath, S. R. Rushforth, J. L. Sims, R. C. Sims, W. A. Wurtsbaugh

Reports

No abstract provided.

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