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Articles 68881 - 68910 of 75062

Full-Text Articles in Engineering

Placement Rates For Highway Embankments With Vertical And Horizontal Drainage : Informational Report, A. G. Altschaeffl, Sabanayagam Thevanayagam Jan 1987

Placement Rates For Highway Embankments With Vertical And Horizontal Drainage : Informational Report, A. G. Altschaeffl, Sabanayagam Thevanayagam

JTRP Technical Reports

No abstract provided.

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The Effect Of The Tribromide Complex Reaction On The Oxidation/Reduction Current Of The Br2/Br– Electrode, P K. Adanuvor, Ralph E. White, S. E. Lorimer Jan 1987

The Effect Of The Tribromide Complex Reaction On The Oxidation/Reduction Current Of The Br2/Br– Electrode, P K. Adanuvor, Ralph E. White, S. E. Lorimer

Faculty Publications

The Br2/Br– electrode reaction with tribromide complex formation reaction in the solution, a chemical-electrochemical (C-E) type reaction, has been investigated in order to determine the effect of the chemical reaction on the electrode kinetics. It is shown that the chemical reaction has little effect on the electrode kinetics at very slow homogeneous reaction rates, but has a more drastic effect on the electrode kinetics at faster homogeneous reaction rates. Also, the kinetics at the electrode are affected by changes in the concentrations of the active species (Br2, Br–, and Br3–) …

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Modeling The Rotating Disk Electrode For Studying The Kinetics Of Electrochemical Reactions, P K. Adanuvor, Ralph E. White, S E. Lorimer Jan 1987

Modeling The Rotating Disk Electrode For Studying The Kinetics Of Electrochemical Reactions, P K. Adanuvor, Ralph E. White, S E. Lorimer

Faculty Publications

A general mathematical model for studying the kinetics of electrochemical reactions at a rotating disk electrode under steady-state potentiostatic conditions is presented. The model, apart from predicting the net and partial current densities at given values of the applied potential, the ohmic potential drop, and the concentration and potential profiles in the solution, also accounts for homogeneous reactions of any order in the solution and noncharge transfer reactions at the electrode surface. The versatility of the model is demonstrated by the application of the model to a variety of complex reaction schemes.

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A Mathematical Model Of A Zinc/Bromine Flow Cell, T. I. Evans, Ralph E. White Jan 1987

A Mathematical Model Of A Zinc/Bromine Flow Cell, T. I. Evans, Ralph E. White

Faculty Publications

A mathematical model is presented for a zinc/bromine flow cell. The model includes a thin porous layer on the bromine electrode and a porous separator. The independent parameters of the porous layer are defined, and their effect on cell performance during charge and discharge is investigated. The dependence of the round trip energy efficiency on the thickness of the porous layer and mode of discharge is presented. The predictions of the model show that a maximum round trip energy efficiency of 70% should be possible under the design conditions considered.

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Simulation Of The Polarization Curves For Oxygen Reduction At A Rotating Disk Electrode, P. K. Adanuvor, Ralph E. White Jan 1987

Simulation Of The Polarization Curves For Oxygen Reduction At A Rotating Disk Electrode, P. K. Adanuvor, Ralph E. White

Faculty Publications

The electrochemical reduction of oxygen in 1M NaOH solution is simulated at a rotating disk electrode. Steady-state polarization curves are presented for possible reaction schemes for the reduction process. The effect of changes in the kinetic parameters on the polarization curves is demonstrated and special attention is focused on the production of hydrogen peroxide.

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Utility Of An Empirical Method Of Modeling Combined Zero Gap/Attached Electrode Membrane Chlor-Alkali Cells, Clifford W. Walton, Ralph E. White Jan 1987

Utility Of An Empirical Method Of Modeling Combined Zero Gap/Attached Electrode Membrane Chlor-Alkali Cells, Clifford W. Walton, Ralph E. White

Faculty Publications

An extensive survey of the Docktor-Ingenieur Dissertationen of Jakob Jörissen and Klaus-R. Menschig, both originally from the Universität Dortmund, is presented in regard to the empirical modeling of membrane chlor-alkali cells and how it can be applied to a combined zero gap/attached porous electrode layer membrane cell. Particular emphasis isplaced on Menschig's work on zero gap (ZG) and attached porous electrode layer (APEL) membrane chlor-alkali cells, the first such research to appear in the open literature. Menschig developed various computer programs to characterize these ZG and APEL membrane chlor-alkali cells. He characterized these cells by using the following parameters: the …

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A Review Of Mathematical Modeling Of The Zinc/Bromine Flow Cell And Battery, T. I. Evans, Ralph E. White Jan 1987

A Review Of Mathematical Modeling Of The Zinc/Bromine Flow Cell And Battery, T. I. Evans, Ralph E. White

Faculty Publications

Mathematical models which have been developed to study various aspects of the zinc/bromine cell and stack of cells are reviewed. Development of these macroscopic models begins with a material balance, a transport equation which includes a migration term for charged species in an electric field, and an electrode kinetic expression. Various types of models are discussed: partial differential equation models that can be used to predict current and potential distributions, an algebraic model that includes shunt currents and associated energy losses and can be used to determine the optimum resistivity of an electrolyte, and ordinary differential equation models that can …

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A Mathematical Model Of A Lead-Acid Cell: Discharge, Rest, And Charge, Hiram Gu, T. V. Nguyen, Ralph E. White Jan 1987

A Mathematical Model Of A Lead-Acid Cell: Discharge, Rest, And Charge, Hiram Gu, T. V. Nguyen, Ralph E. White

Faculty Publications

A mathematical model of a lead-acid cell is presented which includes the modeling of porous electrodes and various physical phenomena in detail. The model is used to study the dynamic behavior of the acid concentration, the porosity of the electrodes, and the state of charge of the cell during discharge, rest, and charge. The dependence of the performance of the cell on electrode thicknesses and operating temperature is also investigated.

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Slope Length And Surface Residue Influences On Runoff And Erosion, John E. Gilley, S. C. Finkner, G. E. Varvel Jan 1987

Slope Length And Surface Residue Influences On Runoff And Erosion, John E. Gilley, S. C. Finkner, G. E. Varvel

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Runoff rate, runoff velocity , sediment concentration and soil loss rate of rills or overland flow channels were measured at selected downslope distances on plots with varying rates of sorghum and soybean residue, runoff rate, runoff velocity and soil loss rate usually increased with downslope distance. In general, the presence of greater amounts of crop residue reduced sediment concentration and soil loss rate along the entire slope length. Substantial variations in runoff rate, runoff velocity, sediment concentration and soil loss rate were found with downslope distance on some residue treatments.

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Slot Injection Of Herbicides, Paul J. Jasa, Elbert C. Dickey, Thomas R. Peterson Jan 1987

Slot Injection Of Herbicides, Paul J. Jasa, Elbert C. Dickey, Thomas R. Peterson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Injection of thiocarbamate herbicides into a slot created by a coulter was evaluated during a 3-year study in southeastern Nebraska. Control of shattercane, the dominant weed, with the slot injector was similar to conventional double disk incorporation. In both tilled and untilled surface conditions, the slot injector placed the herbicide into the soil with minimal disturbance of the soil and residue. Herbicides which are normally broadcast applied were band applied, reducing chemical costs by two-thirds.

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Energy Transmission Into The Human Hand From Vibrating Tools, Douglas D. Reynolds Jan 1987

Energy Transmission Into The Human Hand From Vibrating Tools, Douglas D. Reynolds

Mechanical Engineering Faculty Research

A method for calculating power transmitted to the hands of operators who use vibrating hand tools is presented. Results that relate to a comprehensive multidiscipline NIOSH field study of several hundred chipper and grinder workers who used pneumatic hand tools are discussed. These results indicated that the total power in the frequency range of 6.3 to 1000 Hz transmitted to the hand ranged from 1080 to 7230 J/s for the chisel and from 0.852 to 157 J/s the handle of chipping hammers. For pneumatic grinders the power transmitted to the hands of the tool operators was in the range of …

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A Mathematical Model For The Fate Of Hazardous Substances In Soil: Model Description And Experimental Results, W. Greeney, C. Caupp, Ronald C. Sims Jan 1987

A Mathematical Model For The Fate Of Hazardous Substances In Soil: Model Description And Experimental Results, W. Greeney, C. Caupp, Ronald C. Sims

Biological Engineering Faculty Publications

A mathematical model (VIP) was developed and implemented for evaluating the fate of a hazardous substance in the unsaturated zone of the soil. The model simulates vadose zone processes including volatilization, degradation, adsorption/desorption, advection, and dispersion. Four physical phases in the vadose zone are considered including water, oil, soil grains, and soil-pore air (unsaturated pore space). The Vadose Zone Interactive Processes (VIP) model is appropriate for sites under RCRA and CERCLA (Superfund) categorization since site-specific soil-waste processes affecting transport of hazardous chemicals through the vadose zone are incorporated in the model. A RCRA land treatment system was chosen as the …

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The Rate Of Benzo[A]Pyrene Apparent Loss In A Natural And Manure Amended Clay Loam Soil, M. P. Coover, Ronald C. Sims Jan 1987

The Rate Of Benzo[A]Pyrene Apparent Loss In A Natural And Manure Amended Clay Loam Soil, M. P. Coover, Ronald C. Sims

Biological Engineering Faculty Publications

A study was conducted to evaluate the rate of Benzo[a]pyrene apparent loss from a previously uncontaminated agricultural clay loam soil and to determine the effect of cow manure, as organic substrate amendment, on B[a]P apparent loss. Soil microcosms were spiked with 10 μg/g B[a]P and incubated at 20°C. Triplicate sets of microcosms were periodically removed from incubation and solvent extracted. Concentrations of B[a]P in the soil were determined by HPLC analysis of the extracts. Under the conditions of this study manure was an ineffective amendment for increasing the rate of B[a]P apparent loss in the Durant clay loam soil. In …

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Human Health Effects Assays, Ronald C. Sims, J. L. Sims, R. R. Dupont Jan 1987

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

Biological Engineering Faculty Publications

Health risk assessment of individual environmental chemicals, risks of drinking water supplies, methods for evaluating toxicity, and structure-activity relationships and response-surface methodology represent the focus for 1986. A report of the Steering Committee on Identification of Toxic and Potentially Toxic Chemicals for Consideration by the National Toxicology Pro gram found that, for the majority of substances they examined, data essential for human health hazard assessment were lacking.1 Milestone publications concerning human health effects aspects include works by Mortelmans et al,2 Busch et al,3 Hartman et al,4 Rein,5 Gentile,6 Hodgson,7 and Tagashira and Omura. …

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The Effect Of Temperature On Polycyclic Aromatic Hydrocarbon Persistence In An Unacclimated Agricultural Soil, M. P. Coover, Ronald C. Sims Jan 1987

The Effect Of Temperature On Polycyclic Aromatic Hydrocarbon Persistence In An Unacclimated Agricultural Soil, M. P. Coover, Ronald C. Sims

Biological Engineering Faculty Publications

A laboratory study was conducted to investigate the effect of temperature on the persistence of polycyclic aromatic hydrocarbons (PAHs) incubated in an unacclimated agricultural sandy loam soil. Soil microcosms were spiked with 16 priority pollutant PAHs and placed in incubation chambers at 10, 20, and 30°C. Triplicate sets of microcosms at each temperature were periodically removed from incubation over the 240 day study period and solvent extracted. Concentrations of PAHs in the soil were determined by HPLC analysis of the extracts. Substantial loss of three-ring compounds was observed at all temperatures whereas there was very little apparent loss of five …

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Groundwater Recharge Planning Using Resolvent Discrete Kernels, Richard C. Peralta, Krzyzstof G. Kowalski, H. J. Morel-Seytoux Jan 1987

Groundwater Recharge Planning Using Resolvent Discrete Kernels, Richard C. Peralta, Krzyzstof G. Kowalski, H. J. Morel-Seytoux

Civil and Environmental Engineering Faculty Publications

No abstract provided.

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Decision Support For Optimal Regional Groundwater Management Strategy Modification, Richard C. Peralta, Paul J. Killian Jan 1987

Decision Support For Optimal Regional Groundwater Management Strategy Modification, Richard C. Peralta, Paul J. Killian

Civil and Environmental Engineering Faculty Publications

An interactive decision support program is presented for the rapid modification of optimal regional multiobjective groundwater planning strategies. This capability is important for water managers seeking to select the most satisfactory groundwater management strategies for their areas. The program guides decision maker(s) in refining numerically optimal regional strategies into strategies that may be socially or politically more acceptable. Strategy refinements are made by informed modification of constraining conditions on regional objectives or local variables. Application is illustrated by. modifying a bi criterion, sustained groundwater Withdrawal strategy for minimizing the cost of meeting regional water demand on the Arkansas Grand Prairie, …

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Bear River Water Quality: Phosphorus Control And The Impacts Of Exchanging Water With Willard Reservoir, Darwin L. Sorensen, Craig Caupp, Kenneth W. Barker, Jean M. Ihnat Jan 1987

Bear River Water Quality: Phosphorus Control And The Impacts Of Exchanging Water With Willard Reservoir, Darwin L. Sorensen, Craig Caupp, Kenneth W. Barker, Jean M. Ihnat

Reports

No abstract provided.

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Expected Water Surface Levels For The Great Salt Lake, L. Douglas James Jan 1987

Expected Water Surface Levels For The Great Salt Lake, L. Douglas James

Reports

Flooding at the Great Slat Lake could become a major disaster through the high cost of coping with the rising level, sudden collapse of protective levees, failure of pumping to the West Desert to induce increased evaporation, or, fiscally, by a rapid drop in the lake level just after a large protective decision making in the private sector, provide for the design of hydrologically safe levees, and optimize pumping schemes for moving water within a partitioned lake. Doing so will require crossing major theoretical frontiers in the study of basin scale hydrology in an arid climate and for forecasting extreme …

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Engineering Treatment Of Hazardous Wastewaters Utilizing Dye-Sensitized Photooxidation, Betty-Ann Naeger, R. Ryan Dupont, William M. Moore Jan 1987

Engineering Treatment Of Hazardous Wastewaters Utilizing Dye-Sensitized Photooxidation, Betty-Ann Naeger, R. Ryan Dupont, William M. Moore

Reports

Studies were conducted to determine the applicability of photooxidation for the degradation of selected hazardous and refractory organic compounds. These photochemical oxidation reactions occur through the transfer of energy from electronically excited sensitizer molecules which attain excited states by absorbing visible light energy. Optimum conditions for photooxidation were established based on sensitizer concentration and reaction pH for four polynuclear aromatic pollutants. The rate of photooxidation was found to be independent of the initial substrate concentration for methylene blue-sensitized reactions, and dependent on substrate concentration for solutions without a sensitizing dye. Photolysis of substrate mixtures established acridine and anthracene as photochemically …

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Groundwater Resources Of The Virgin River Basin In Utah, Calvin G. Clyde Jan 1987

Groundwater Resources Of The Virgin River Basin In Utah, Calvin G. Clyde

Reports

The Division of Water Resources is conducting a study of further water development in the Virgin River Basin. This report examines the effects of groundwater development as a part of the overall study. The study area includes about 1000 square miles in the Central Virgin River Basin east of the Hurricane Fault. The deeply incised Virgin River has cut a youthful drainage network with deep canyons and steep escarpments and drains out of southwest Utah across Arizona to Lake Mead in Nevada. A basin-wide geologic map emphasizing groundwater features has been prepared from available reports. Outcrops of the principal sedimentary …

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Modeling And Analysis Of Biospecific Adsorption In A Finite Bath, B. H. Arve, Athanasios I. Liapis Jan 1987

Modeling And Analysis Of Biospecific Adsorption In A Finite Bath, B. H. Arve, Athanasios I. Liapis

Chemical and Biochemical Engineering Faculty Research & Creative Works

A general model is presented and used to predict the dynamic behavior of the adsorption and wash stages of bio specific adsorption (affinity chromatography) in a finite bath. The model accounts for film and diffusional mass transfer resistances as well as for the rates of interaction between adsorbates and ligands. The model is applicable to single and multicomponent bio specific as well as nonspecific adsorption, and the adsorbates may be monovalent or multivalent. The predictions of the model are compared with the experimental data of the adsorption of β‐galactosidase onto immobilized anti‐β‐galactosidase. The results of bio specific adsorption of bivalent …

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The Force On A Lattice Defect In An Elastic Body, R. C. Batra Jan 1987

The Force On A Lattice Defect In An Elastic Body, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

It is shown that the force on a lattice defect in an elastic body is, like the force on a disclination in a nematic liquid crystal, a real force which, for equilibrium, must be balanced by an external force applied to the closed surface enclosing the defect. © 1987 Martinus Nijhoff Publishers.

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Effect Of Material Parameters On The Initiation And Growth Of Adiabatic Shear Bands, R. C. Batra Jan 1987

Effect Of Material Parameters On The Initiation And Growth Of Adiabatic Shear Bands, R. C. Batra

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The thermomechanical problem involving simple shearing of a finite slab made of an isotropic and viscoplastic material is studied with the objective of finding the effect of the strain hardening parameter, strain-rate hardening parameters, thermal softening coefficient and thermal conductivity on the initiation and growth of adiabatic shear bands. The body is placed in a hard loading device, i.e., the velocity is prescribed at its top and bottom surfaces. A shear band is presumed to have formed if the addition of a perturbation in the temperature at the onset of plastic flow results in a localization of the shear strain. …

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Calculation Of Mass Transfer Coefficients In Metal Deposition Using Electrochemical Tracer Techniques, Thomas J. O'Keefe, J. S. Cuzmar, S. F. Chen Jan 1987

Calculation Of Mass Transfer Coefficients In Metal Deposition Using Electrochemical Tracer Techniques, Thomas J. O'Keefe, J. S. Cuzmar, S. F. Chen

Materials Science and Engineering Faculty Research & Creative Works

A modification of the tracer technique of Ettel has been developed for determining mass-transfer coefficients in electrolytes for both electrowinning and electrorefining systems. The method involves the direct measurement of the limiting current density of a more noble tracer ion at low concentration by cyclic voltammetry techniques in an electrolyte of choice. A Ag+tracer in acid copper sulfate is used as the example. Additional tests were made by code positing the tracer with copper to compare the results of the two methods. The effect of copper ion concentration and temperature on the electrochemical and transport properties of the solution were …

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Computer-Aided Testing Of Electrical Machines: Software Development, Max Darwin Anderson, Steven A. Hauk, Robert Laramore, Hardy J. Pottinger Jan 1987

Computer-Aided Testing Of Electrical Machines: Software Development, Max Darwin Anderson, Steven A. Hauk, Robert Laramore, Hardy J. Pottinger

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

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Computer-Aided Testing Of Electrical Machines: Software Development, Max Darwin Anderson, Steven A. Hauk, Robert Laramore, Hardy J. Pottinger Jan 1987

Computer-Aided Testing Of Electrical Machines: Software Development, Max Darwin Anderson, Steven A. Hauk, Robert Laramore, Hardy J. Pottinger

Electrical and Computer Engineering Faculty Research & Creative Works

Computer-aided test stations have been developed for research, experimentation, and testing of electric motors and generators. Data acquisition and control of the machines and drives are provided through a computer and its interfaces. Machines are connected to the computer through transducers for data acquisition, and power electronic drives for machine control. General software was written to enable the monitoring of all transducers continuously on the CRT screen while giving the user manual control of the machines and drives. Specialized software was written for automatic control of the induction, dc, and synchronous machines for specific experiments on each type of machine. …

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Current That Kills., Burns E. Hegler Jan 1987

Current That Kills., Burns E. Hegler

Electrical and Computer Engineering Faculty Research & Creative Works

The authors point out the hazards associated with electricity. Several methods for preventing or coping with inadvertent shocks are described.

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Impact Of Automation On Process Control Decision-Making, Steven M. Miller, Susan R. Bereiter Jan 1987

Impact Of Automation On Process Control Decision-Making, Steven M. Miller, Susan R. Bereiter

Research Collection School Of Computing and Information Systems

This paper investigates changes in the process control of a vehicle assembly plant which had been modernized from a principally manual procedure to one that uses programmable automation extensively. Process control is defined as the information flow and decision-making required to perform basic process operations. We investigate the effects of implementing a computer-integrated production system on the amount and types of process control decision-making and on the distribution of process control decision-making between humans and machines. After automation, the emphasis on decisions regarding product quality specifications increased and the emphasis on decisions related to flexibility in handling a variety of …

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Estimation Approach To Locating Buried Geological Interfaces, A. Omar, A. Addeeb, C. Slivinsky, Richard E. Dubroff Jan 1987

Estimation Approach To Locating Buried Geological Interfaces, A. Omar, A. Addeeb, C. Slivinsky, Richard E. Dubroff

Electrical and Computer Engineering Faculty Research & Creative Works

The objective of the estimation work described in this paper is to improve algorithms for reconstructing the geometric configuration of acoustic reflecting surfaces. The conventional migration method of locating these surfaces is reviewed. A recent imaging condition which is closely related to the boundary condition at the geological interface is then described. This later procedure results in two outputs. One can be used to reconstruct the shape of the unknown acoustic reflector, while the second output estimates the acoustic wavespeed on the transmission side of the boundary. When noise is present in the reflected signal, the performance of the method …

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