Engineering Commons^™

Proposed Structure For Large Quantum Interference Effects, S. Datta, Michael R. Melloch, S. Bandyopadhyay, Mark S. Lundstrom

Department of Electrical and Computer Engineering Faculty Publications

In this letter we propose and analyze a new semiconductor structure that can be fabricated by present day technology and can lead to large quantum interference effects with potential device applications.

Effect Of Impurity Trapping On The Capacitance‐Voltage Characteristics Of N‐Gaas/N‐Algaas Heterojunctions, K. L. Tan, Mark S. Lundstrom, Michael R. Melloch

Department of Electrical and Computer Engineering Faculty Publications

We have studied the capacitance-voltage (C- V) characteristics of Schottky barriers on inverted nGaAs/ N-AIGaAs and normal N-AIGaAs/n-GaAs heterojunctions. Impurities introduced during film growth produced a negative sheet charge of 6.0 X 10 II cm -2 at the interface of the inverted n-GaAs/N-AIGaAs heterojunction. The effectiveness of GaAs quantum wells in trapping these impurities was investigated. GaAs quantum wells 20 A wide were placed in intervals of 2500 A for the first 0.75 pm of the AIGaAs layer; in the last 0.25 pm, the periodicity of the quantum wells was progressively decreased by half with the last quantum well placed …

A Loran-C Antenna Coupling Unit., Timothy Andrew Reilly 1963-

Electronic Theses and Dissertations

This project is the design of an antenna-coupling unit (ACU) that will operate with the Texas Instruments LORAN-C receiver and a 28-inch antenna. The height of the antenna used at the present is eight feet. Since the application of LORAN-C positioning is being expanded to vehicular location, an eight-foot antenna is not practical. The shorter antenna is necessary to prohibit striking trees, overpasses, etc. The newly designed ACU has more voltage gain to compensate for the attenuation of the incoming signal due to the shortening of the antenna. It also has a bandpass of 90 KHz-110 KHz with the center …

Drilled Pilers Used For Slope Stabilization, Michael William Oakland, Jean-Lou Chameau

JTRP Technical Reports

No abstract provided.

Stabl6 With Reinforcing Layer Option: User's Manual : Implementation Report (2), Dana Norman Humphrey, R. D. Holtz

JTRP Technical Reports

No abstract provided.

Traffic Volume Forecasting Methods For Rural State Highways, Jon D. Fricker, Sunil K. Saha

JTRP Technical Reports

No abstract provided.

A Remote Office Automation Analysis, J. R. Wright, Eric David Kosiba, Gregory Raymond Stukel

JTRP Technical Reports

No abstract provided.

Nebraska Summary: S091 S.A.M.E Explorer 70dt, 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 …

A Mathematical Model Of A Zn/Br2 Cell On Charge, M J. Mader, Ralph E. White

Faculty Publications

A mathematical model of a parallel plate electrochemical cell with a separator and a homogeneous bulk reaction is presented. The model is based on the Zn/Br₂ redox couple and can be used as an aid for the design of an efficient rechargeable storage battery. It is shown that four independent variables exist for the system at a fixed temperature: the effective separator thickness, the residence time, the channel width, and the potential driving force. Performance criteria of interest for the Zn/Br₂ battery are defined. Predictions of performance during the charging process are presented. It is shown that the …

An Exact Analysis For Efficient Computation Of Random-Pattern Testability In Combinational Circuits, Sharad C. Seth, Bhargab B. Bhattacharya, Vishwani Agrawal

School of Computing: Conference and Workshop Papers

Experimental evidence shows that low testability in a typical circuit is much more likely due to poor observability than poor controllability. Thus, from theoretical and practical standpoints, it is important to develop an accurate model for observability computation. One such model, in terms of supergates, is proposed in the first part of this paper thus complimenting our earlier work. It is now possible to obtain exact random-pattern testability for each line in a circuit.

The second part of the paper analyzes the supegate structure of a circuit from a graph theoretic viewpoint. Finding a supergate is related to determining the …

Location Of Habitat Important To Federally Listed Bird Species On The Missouri National Recreational River, Kent Kennlyne, Jim Ruwaldt, Frank Howe, Steve Riley, David Gilbraith

United States Army Corps of Engineers, Omaha District

Literature reviews, field observations, and personal contacts were used to identify areas important to inter lor least terns (Sterna antillarum athalassos), piping plovers (Charadrius melodus), and bald eagles (Aaliaeetus leucocephalus) on the 58-mlle-long Mlssouri National Recreational Rlver. Areas were prioritized according to suitability of habitat and recorded use by these species. Thirty-nlne miles were classified as Priority I least tern and piping plover nesting habitat; three miles were classified as Priority II and 16 miles as Priority III habitat. Bald eagle habitat was considered separately on both sides of the river (116 miles total), …

Sediment And Dye Concentration Effects On Fluorescence, S. C. Finkner, John E. Gilley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Because of the relatively large sediment concentrations sometimes found on upland regions, adsorption of fluorescent dye onto sediment may be of concern. A laboratory study was conducted to identify the effects of sediment and dye concentration on adsorption. Sediment and dye concentration were both found to significantly affect adsorptive dye loss of rhodamine WT and sulpho rhodamine B.
Regression equations were developed which related dye adsorption to sediment and dye concentration. For a particular soil and dye material, regression equations may be used to correct for adsorptive dye loss. Sulpho rhodamine B is recommended as the dye of choice for …

Runoff And Erosion As Affected By Corn Residue: Part I. Total Losses, John E. Gilley, S. C. Finkner, R. G. Spomer, L. N. Mielke

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The effects of verying rates of corn residue on runoff and erosion from a loess soil in southwestern Iowa were measured using a rainfall simulator. Consistent reductions in runoff, sediment concentration and soil loss resulted from increased residue application. Small amounts of surface cover produced substantial reductions in erosion. A regression equation relating surface cover to residue weight was obtained. Equations describing relative runoff, sediment concentration and soil loss as a function of surface cover were also developed using regression analysis.

Estimating Residue Cover, Elbert C. Dickey, Paul J. Jasa, David P. Shelton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Crop residue management through conservation tillage is one of the best and most efficient methods farmers have to control soil erosion. Each year about 140 million tons of topsoil are eroded from Nebraska farmlands. Recent research shows that farmers can greatly reduce this loss by maintaining a residue cover of at least 20 to 30 percent after all tillage and planting operations. Leaving this amount of residue can reduce water caused erosion by 50 percent of what it would be from a cleanly tilled field, while leaving more residue will reduce soil losses even further. Conservation tillage and residue management …

Soil Erosion From Tillage And Planting Systems Used In Soybean Residue: Part I - Influences Of Row Spacing, David P. Shelton, Paul J. Jasa, Elbert C. Dickey

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A rainfall simulator was used to compare soil losses from various tillage and planting systems used in residue from soybeans which had been grown in both wide and narrow spaced rows the previous season. Up and- down hill tillage and planting treatments ranging from a double disk system to no-till planting were evaluated using replicated plots on a silt loam soil in the Nora Series having a 10% slope.

Tillage and planting systems used in soybean residue from narrow spaced rows had soil erosion and soil erosion rates that were reduced by approximately 50% compared to the same systems used …

Soil Erosion From Tillage And Planting Systems Used In Soybean Residue: Part Ii - Influences Of Row Direction, Paul J. Jasa, Elbert C. Dickey, David P. Shelton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

A rainfall simulator was used to compare soil losses from tillage and planting systems used in residue from soybeans. The study was conducted on a silty clay loam soil in the Wymore Series with a 5% slope and on a silt loam soil in the Nora Series with a 10% slope. Tillage and planting treatments, ranging from a moldboard plow system to no-till planting, were evaluated both up and- down hill and on the contour using replicated plots.

For the first rainfall event after tillage and planting, the average soil loss for all systems on the contour was 3.0 t/ha …

Parallel-Plate Electrochemical Reactor Model: A Method For Determining The Time-Dependent Behavior And The Effects Of Axial Diffusion And Axial Migration, T. V. Nguyen, C. W. Walton, Ralph E. White, J. Van Zee

Faculty Publications

A method is presented for determining the effects of time dependence, axial diffusion, and axial migration in aparallel-plate electrochemical reactor (PPER). The method consists of formulating the governing equations and applying a numerical integration technique to solve a set of time-dependent, nonlinear, coupled, multidimensional equations. This formulation reveals that the steady-state performance of the PPER depends on the cell potential and three dimensionless groups. Predictions of the concentration, potential, and local current distributions in a PPER are presented for the electrowinning of copper from an aqueous, hydrochloric acid solution. These predictions show that axial diffusion and axial migration are significant …

Simple Models For Diaphragm-Type Chlorine/Caustic Cells Ii. Effect Of Acidic Anolyte On Steady-State Caustic Yield, John Van Zee, Ralph E. White

Faculty Publications

A simple steady-state model of a diaphragm-type chlorine/caustic cell in which the diaphragm is divided into two regions by a homogeneous acid-base reaction is presented. The location of the reaction affects significantly the caustic yield and effluent concentration. The model is used to predict the location of this reaction as a function of the operating variables, the physical constants, and three measurable properties of the diaphragm. These measurable properties are the MacMullin number or resistivity ratio of electrolyte-filled diaphragm relative to the electrolyte, the Darcy's law diaphragmpermeability, and the diaphragm thickness. The model is used to predict a maximum in …

Simple Models For Diaphragm-Type Chlorine/Caustic Cells I. Dynamic Behavior, John Van Zee, Ralph E. White, A T. Watson

Faculty Publications

A simple model of the dynamic behavior of a diaphragm-type chlorine/caustic cell is presented. The model is based upon measurable diaphragm properties and the mass transfer of hydroxyl ion through the diaphragm. The anolyte is modeled simply as a region in which the OH^– ion concentration is fixed, the diaphragm is modeled as a plug-flow reactor with an electrochemical reaction occurring at the catholyte/diaphragm interface where the cathode is placed, and the catholyte is modeled as a completely stirred flow reactor. Analytical integration of the governing equations for thesemodels yields two mathematical expressions: one for the concentration distribution of …

Parallel Plate Electrochemical Reactor Model: Material Balance Closure And A Simplification, M J. Mader, C W. Walton, Ralph E. White

Faculty Publications

A material balance closure calculation is presented to test the consistency of a previously published model of a parallelplate electrochemical reactor. New expressions are used in this procedure to calculate the average concentration of species i and the average current density for reaction j from the predicted concentration and potential distributions. Also, the previously presented model equations are simplified by assuming that the axial concentration gradient for species i can be approximated by a step change from the known feed concentration to the unknown outlet concentration. This one-step model provides a qualitative evaluation of cell performance and adds insight into …

A Mathematical Model For A Parallel Plate Electrochemical Reactor, Cstr, And Associated Recirculation System, T V. Nguyen, C W. Walton, Ralph E. White

Faculty Publications

A mathematical model is presented for a system comprised of a parallel plate electrochemical reactor (PPER) and a continuous, stirred-tank reactor (CSTR) under both total and partial recycle. The model is used to predict the time dependent behavior of the electrowinning of copper from an aqueous, hydrochloric acid solution. The model includes many important aspects of a PPER/CSTR system which have been neglected previously. These aspects are the kinetics of electrode reactions, the electroneutrality condition, three mass transfer processes for ionic species in the electrolyte (diffusion, ionic migration, and convection) and the electrode gap in the PPER, and the inclusion …

Optimizing The Rapid Evolution Of Target Groundwater Potentiometric Surfaces, Richard C. Peralta, Krzysztof G. Kowalski

Civil and Environmental Engineering Faculty Publications

THE long-term availability of adequate groundwater for sustainable irrigated agricultural production can be assured by causing the evolution and maintenance of an appropriate potentiometric (piezometric) surface in utilized aquifers. By providing adequate saturated thickness and hydraulic gradients and heads. such a surface affords some protection from the effects of drought. economic: hardship, and environmental or legal complications. Procedures for determining desirable or optimal regional steady-state groundwater potentiometric surfaces have been reported by several researchers. An existing polcmiometric surface can be forced to evolve into a desirable 'target' surface if it is subjected through time to the proper combination of recharges …

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

Biological Engineering Faculty Publications

Discussion of the exponential increase in environmental toxicological information and an approach for organizing and using the information was presented by Lu and Wassom.¹ A user's guide to the Registry of Toxic Effects of Chemical Substances (RTECS) was published by NIOSH² that defines the record layouts and describes the types of data contained in the computer tape version of the 1984 Edition of the RTECS.³ A text summarizing information on approximately 800 toxic chemicals was edited by Sittig.⁴ Milestone publications concerning fundamentals of toxicology with environmental applications included the works of Gentile,⁵ Ashby,⁶ Mortel …

Water Quality Management Studies For Water Resources Development In The Bear River Basin, Darwin L. Sorensen, Craig Caupp, William J. Grenney, Steve Eberl, Jay J. Messer, Phillip Ludvigsen, Charles W. Ariss

Reports

Summary: The quality of water that develops in the proposed reservoirs of the Upper Bear River Storage Project will determine the possible uses of the water. Previous studies of water quality in the Bear River and its tributaries have reported water quality problems relating to nitrate ion, sanitary indicator bacteria, suspended solids, and phosphorus concentrations. Most point sources of water pollution inthe basin have been eliminated or improved in quality, but nonpoint sources of pollution continue to degrade the quality of the Bear River. Concentrations of phosphours have been sufficiently high to encourage dense algal growth and create eutrophic conditions …

Utah Water Research Laboratory, Utah Center For Water Resources Research, A Program Overview, L. Douglas James, Donna H. Falkenborg

Reports

Organization of Prepared Material: This overview presents the water resources research program administered through the Utah Water Research Laboratory and the Utah Center for Water Resources Reserach. The document is prepared for an internal review by a faculty team organized by the Administration of Utah State university and an external review by a team organized by the U.S. Geological Survey as part of a national effort to evaluate the water research centers in every state over a 2-year period. These materials are prepared to stimulate discussion and spark innocative ideas for building an even stronger program. The UWRL/UCWRR administration sees …

Economic Evaluation Of Conservation Concepts For Municipal Water Systems, Trevor C. Hughes, Rangesan Narayanan, Mac Mckee, A. Bruce Bishop, Robert Leconte, Sumani Al-Hassan

Reports

Five concepts for conservation of municipal water supply are analyzed from an economic efficiency perspectice. They include: 1) seasonal pricing (for reduction of peak period water use), 2) dual water systems (separate high quality drinking water and untreated outdoor irrigation systems), 3) imported water transmission facility capacity optimization, 4) flow restricting devices, and 5) short-term rationing concepts. Optimization models, including generalized model generators, were developed for analysis of the first three concepts and demonstrated by applications to cities in Utah. The flow restricting device and short-term rationsing concept analyses applied approaches taken from the literature to example sites in Utah. …

Feasibility Of Incorporating Aquaculture, Solar Pond Energy, And Mineral Extraction Technologies To Control Localized Sources Of Salinity In River Systems, J. Paul Riley

Reports

Salinity poses a serious and continuing problem to the full utilization of water resources in many river basins of western U.S. A variety of management measures have been employed to mitigate the damaging effects of salinity on agricultural crops as well as on municipal and industrial uses of water. The Colorado River Basin Salinity Control Act illustrates the logic of addressing the problem on a basin wide basis under a strategy that give priority to those localized sources of salinity that contribute disproportionately large amounts of salt to the system. It remains then to devise control measures specific to each …

National Surface Water Survey: National Stream Survey Phase I--Pilot Survey, J. J. Messer, C. W. Ariss, R. Baker, S. K. Drouse, K. N. Eshleman, P. R. Kaufmann, R. A. Linthurst, J. M. Omernik, W. S. Overton, M. J. Sale, R. D. Schonbrod, S. M. Stambaugh, J. R. Tuschall Jr.

Reports

No abstract provided.

Appendices: Water Quality Management In Utah Mountain Watersheds, Keith R. Kimball, E. Joe Middlebrooks

Reports

No abstract provided.

Water Quality Management In Utah Mountain Watersheds, Keith R. Kimball, E. Joe Middlebrooks

Reports

What Quality Management in Utah Mountain Streams: Several years of thorough monitoring of water quality parameters in Little Cottonwood Creek in Salt Lake County, Utah, measured the natural levels of the major water constituents, spotted significant (largely nonpoint) pollution sources, identified the pollutants deserving primary attention, and suggested the approaches to land and water management for pollution control in a mountain watershed used primarily for recreation purposes. Bacterial pollution is greater at night than during the day, on weekends than on week days, and in the summer than in the winter. Mineral content is of natural origin and largely explained …