Engineering Commons^™

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 …

Sustained Groundwater Yield And Conjunctive Use Via Target Levels In A Reasonable Use State, Ann W. Peralta, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

No abstract provided.

Optimal Piezometric Surface Management For Groundwater Contaminant Control, Richard C. Peralta, R. L. Ward

Civil and Environmental Engineering Faculty Publications

A methodology is described for efficiently evaluating possible injection/extraction pumping schemes to most economically contain a groundwater contaminant plume. A multi-objective model is analyzed with a micro-computer. Simulation and optimization is performed by employing the response matrix method.

Potential Arkansas And White Rivers Water Available For Diversion To The Grand Prairie, W. Douglass Dixon, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

At the present time. the rate of groundwater use in the Grand Prairie region of Arkansas exceeds natural replenishment of the underlying aquifer. Most of the groundwater is used for agricultural production. [f current agricultural water needs of the region are to be satisfied under sustained yield conditions. supplemental surface water will be required. The objective of this study is to assess the viability of the Arkansas and White Rivers as sources of supplemental water for meeting water needs in excess of those which can be met with groundwater.

Assuring Sustained Groundwater Availability And Achieving Conjunctive Water Management By Target Approaches, Richard C. Peralta, Ann W. Peralta

Civil and Environmental Engineering Faculty Publications

No abstract provided.

Review And Evaluation Of Current Design And Management Practices For Land Treatment Units Receiving Petroleum Wastes, J. P. Martin, Ronald C. Sims, J. Matthews

Biological Engineering Faculty Publications

Land treatment is categorized in the Resource Conservation and Recovery Act of 1976 (RCRA) as one of the land disposal options for managing hazardous wastes. Land treatment relies on detoxification, degradation, and immobilization of hazardous waste constituents within the defined treatment zone to ensure protection of surface water, groundwater, and air. Under the authority of Subtitle C of RCRA, the U.S. Environmental Protection Agency has promulgated regulations governing the treatment of hazardous wastes in land treatment units (40 CRF, Part 264, Subpart M, July, 1982).

This paper describes the land treatment practices used by petroleum waste land treatment facilities in …

Maintaining Target Groundwater Levels Using Goal‑Programming: Linear And Quadratic Methods, Amin Yazdanian, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

Sustained-yield groundwater management strategies can be designed to closely maintain preassigned 'target' levels. Quadratic and linear goal-programming objective functions are used in two distinct models which minimize the sum of differences between 'target' and regionally optimized sets of groundwater levels. Constraints and bounds imposed on extractions, recharge and heads in each model assure that developed strategies are physically feasible and sustainable. The linear model is computationally more time-efficient, but numerical difficulties due to equality constraints are encountered when it is applied to large groundwater systems_ The quadratic model requires less computer storage and is applied to the Grand Prairie of …

Optimal Modification Of Regional Potentiometric Surface Design For Groundwater Contaminant Containment, Bithin Datta, Richard C. Peralta

Civil and Environmental Engineering Faculty Publications

A procedure for optimal modification of a regional potentiometric surface designed solely on the basis of quantitative considerations, is presented. The modification in the potentiometric surface is necessary to incorporate groundwater quality criteria in a critical subsystem of the entire region. The resulting optimal regional potentiometric surface ensures: sustained groundwater yields from the aquifer, compliance with water quality constraints at critical cells of the sub· system (which are identified by a solute transport simulation model), and the most economic conjunctive management of surface and groundwater.

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 …

Expected Effects Of In-Lake Dikes On Water Levels And Quality In The Farmington Bay And The East Shore Areas Of The Great Salt Lake, Utah (Executive Summary), Duane G. Chadwick, J. Paul Riley, Alberta J. Seierstad, Darwin L. Sorensen, Norman E. Stauffer

Reports

Introduction: The Great Salt Lake is a terminal lake and as such is one of the major inland bodies of salt water in the world, and the largest lake of brine in the western hemisphere. Its unique features, including its mineral rich waters and interesting shores and islands, make it appealing to both industry and vacationers. Until recently, some of the great waterfowl sanctuaries in the U.S. existed along the easterly and northerly shores of the lake. However, during the past three years record breaking inflow volumes and lower than normal evaporation rates have caused an unprecidented rate of rise …

Expected Effects Of In-Lake Dikes On Water Levels And Quality In The Farmington Bay And The East Shore Areas Of The Great Salt Lake, Utah, Duane G. Chadwick, J. Paul Riley, Alberta J. Seierstad, Darwin L. Sorensen, Norman E. Stauffer

Reports

Introduction: The Great Salt Lake is a terminal lake and as such is one of the major inland bodies of salt water in the world, and the largest lake of brine in the western hemisphere. Its unique features, including its mineral rich waters and interesting shores and islands, make it appealing to both industry and vacationers. Until recently, some of the great waterfowl sanctuaries in the U.S. existed along the easterly and northerly shores of the lake. However, during the past three years record breaking inflow volumes and lower than normal evaporation rates have caused an unprecidented rate of rise …

Evaluation Of Volatilization Of Hazardous Constituents At Hazardous Waste Land Treatment Sites, R. Ryan Dupont, J. A. Reineman

Reports

The magnitude and extent of volatile organic emissions from hazardous waste land treatment systems were evaluated in laboratory and field studies using complex petroleum refining hazardous wastes. Laboratory experiments were conducted using two soils and a intert construction sand to investigate the emission flux rates of seven volatile constituents, i.e., benzene, toluene, ethylbenzene, p-, m-, o-xylene, and naphthalene, from API Separatory Sludge and Slop Oil Emulsion Solids wastes in column and flask laboratory units as a function of waste application rate, application method (surface versus subsurface), soil type and soil physical characteristics. Field experiemtns were conducted at an active petroleum …

Fast Discharges In Thin Liquid Layers, Charles J. Frei, Aidan O'Dwyer

Conference papers

Several mechanisms can be at work when electrical discharges occur across a thin layer of an insulating liquid. The evidence is derived from the time-lag distributions of series of consecutive discharges when the measurements are performed with a sequence of constant voltage pulses.

Evaluation Of Two Models For Light Transmission In Biological Materials, R. A. Cavaletto, S. Upadhyaya, M. O'Brien, T. Cahill

BioResource and Agricultural Engineering

Two light transmission models for biological materials are developed and evaluated. The energy balance model showed promise. It's developed as a 3 coefficient model permitting varied sample absorption and scattering properties. The second model performed unsatisfactorily.

Total Refraction At Oblique Incidence By A Transparent Bilayer Coating On A High-Index Transparent Or Absorbing Substrate, R. M.A. Azzam, Karim Javily

Electrical Engineering Faculty Publications

Transparent bilayer coatings that produce total refraction (TR) of obliquely incident monochromatic light into an underlying substrate are considered. When the substrate is transparent, it is shown that TR takes place without any accompanying change of polarization. Totally refracting bilayers are realizable in the IR where high-refractive-index substrates are available. This is illustrated by a BaF₂–ZnSe bilayer on a Ge substrate at a 10.6-μm (CO₂-laser) wavelength and 45° angle of incidence. Limited changes of the angle of incidence, wavelength, and refractive indices and thicknesses of the two films of the bilayer are introduced, and their effects …