Digital Commons Network^™

A Field Method For Assessing Borehole Friction For Directional Well Casing, Eric E. Maidla, Andrew K. Wojtanowicz

Faculty Publications

A field procedure to evaluate the borehole friction factor between a pipe string and a borehole was developed. The primary concern of this research was to investigate and mathematically describe the drag associated with casing runs in directional wells through the use of the two-dimensional approach. The borehole friction factor was found, through an iterative procedure, by matching the calculated hook load to the measured one at the surface. The borehole friction factor was calculated as the unique value for the match. This study shows the necessary precision requirements for the hook load measurement instrumentation and presents three different types …

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. …

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

Faculty Publications

No abstract provided.

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.

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.

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.

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.

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.

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 …

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.

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 …

Communication Strategies And Psychological Processes In Interlanguage Written Discourse, B Kumaravadivelu

Faculty Publications

Several papers have appeared on the strategies of communication used by L2 learners. However, very little work has been done to determine the underlying psychological processes that generate communication strategies (CS). This paper assumes that any description of CS should be based on a description of the processes governing CS. The paper attempts to correlate CS with psychological processes by analyzing interlanguage (IL) written discourse produced by advanced Tamil learners of English as a Second Language.

Quasilinear Evolution Equations In Nonclassical Diffusion, Kenneth Kuttler, Elias Aifantis

Faculty Publications

After describing the motivation leading to some nonclassical diffusion equations, we formulate a general abstract nonlinear evolution equation and establish existence of solutions. Then we return to the original equation and discuss particular initial-boundary value problems.

Comparison Of Effective Medium Procedures For Optical Modeling Of Laminar Structures, David D. Allred, Robert F. Edgerton

Faculty Publications

This study addresses the question, "How can the optical properties of matter in ultrathin amorphous nonmetallic films in multilayers best be determined from reflectance (R) and transmission (T) measurements?" A blue shift in the band gap of plasma CVD a-Si:H/a-SiNx:H multilayers was reported several years ago. It was suggested that the shift in the band gap, Eg, Relative to bulk a-Si:H as given by the Tauç plot was due to quantum confinement effects. The purpose of this study is to evaluate the usefulness of various effective media theories (EMT) for determining the optical constants of materials in a multilayer and …

On The Use Of A Modified Square-Well Model For Prediction And Correlation Of Thermal Diffusion Factors In Binary Liquid Mixtures, Richard L. Rowley, S. C. Yi

Faculty Publications

Recently reported thermal diffusion factors obtained from heats of transport have been used to test the ability of existing theories to predict thermal diffusivities using model parameters regressed from pure component transport data. None of the theories tested were able to provide even qualitative agreement with experiment. However, predictions using a square-well Enskog theory, modified here for consistency with normal experimental definitions, were found to be approximately correct using pure-component square-well parameters regressed from viscosity and thermal conductivity and an assumed mixing rule for cross terms. Predicted values are very sensitive to the energy mixing rule, and correlation of experimental …

Heats Of Transport From Diffusion Thermoeffect Measurements On Binary Liquid Mixtures Of Carbon Tetrachloride With Benzene, Toluene, 2-Propanone, N-Hexane, And N-Octane, Richard L. Rowley, S. C. Yi

Faculty Publications

Measurements of heats of transport are reported for binary liquid mixtures containing carbon tetrachloride and benzene, toluene, 2-propanone, n-hexane, or n-octane at 298 K and ambient pressure. Additionally, measurements were made at 308 K for carbon tetrachloride with benzene, toluene, and 2-propanone. The corresponding heat-mass Onsager coefficients are also reported, from which thermal diffusion ratios have been calculated based on Onsager reciprocity. These data will be used in a companion paper to report a modified Enskog method for correlation and prediction of heats of transport.

Definition Of An Asymmetric Domain For Intercrystalline Misorientation In Cubic Materials In The Space Of Euler Angles, Brent L. Adams, Junwu Zhao

Faculty Publications

The authors wish to acknowledge the support of the United States Department of Energy, Office of Basic Energy Sciences, under grant No. DE-FG02-85ER45203. Critical review by Professor Dorian Hatch of the Physics Department at Brigham Young University is gratefully acknowledged. A new asymmetric domain for intercrystalline misorientation is defined in the space of Euler angles for materials exhibiting cubic (Oh point-group) lattice symmetry. The invariant measure for this new domain is nearly constant; this is in significant contrast to the previous domain defined by MacKenzie [Biornetrika (1958), 45, 229-240]. Distribution functions in the misorientation can now be represented with greater …

Backfilling Canals To Mitigate Wetland Dredging In Louisiana Coastal Marshes, Christopher Neill, R. Eugene Turner

Faculty Publications

Returning canal spoil banks into canals, or backfilling, is used in Louisiana marshes to mitigate damage caused by dredging for oil and gas extraction. We evaluated 33 canals backfilled through July 1984 to assess the success of habitat restoration. We determined restoration success by examining canal depth, vegetation recolonization, and regraded spoil bank soils after backfilling. Restoration success depended on: marsh type, canal location, canal age, marsh soil characteristics, the presence or absence of a plug at the canal mouth, whether mitigation was on- or off-site, and dredge operator performance.

Backfilling reduced median canal depth from 2.4 to 1.1 m, …

Surface-To-Surface Transition Via Electromagnetic Coupling Of Coplanar Waveguides, Robert W. Jackson, David W. Matolak

Faculty Publications

A transition is investigated which couples coplanar waveguide on one substrate surface (a motherboard) to coplanar waveguide on another substrate surface (a semiconductor chip or subarray) placed above the first. No wire bonds are necessary. A full-wave analysis using coupled line theory is presented and verified experimentally. The use of this transition for coupling to millimeter-wave integrated circuits is discussed.

A Public Ministry By All The Baptized?, Patrick R. Keifert

Faculty Publications

Any discussion of the ministry of the baptized eventually reaches a point where someone asks, “If all the baptized are ministers, then why and how do we distinguish between the ministry of clergy and laity?” One promising answer begins, “The clergy have a public ministry....” The unspoken half of that answer, seldom said, but powerfully lived out in contemporary capitalistic cultures is, “The laity’s ministry is private.” This response constricts the scope of the gospel and plays into the contemporary gulf between the public and private dimensions of our lives.

Moment Method Analysis Of The Electric Field Under Ehv Transmission Lines, T. L. Simpson, Charles W. Brice

Faculty Publications

The charge moment method is applied to the analysis of electric fields under EHV transmission lines over irregular terrain.

Gamma And Dynamic Range Needs For An Hdtv Electronic Cinematography System, Harry Mathias

Faculty Publications

A cinematographer's perspective regarding gamma and contrast manipulation in video and film is given. In film, a selective exposure can be used; the negative characteristic is the cinematographer's creative tool. The use of film as a video medium is considered, both negative and positive transfer. Contrast reproduction in the video medium is explained, and film and video gammas are compared. Also compared with the film gamma is the gamma obtained with an HDTV camera. Future trends are sketched, and current HDTV specifications are compared with the characteristics of film. Predictability and consistency of results, that is, the final image on …

Decision-Directed Multivariate Empirical Bayes Classification With Nonstationary Priors, Wynn C. Stirling, A. Lee Swindlehurst

Faculty Publications

A decision-directed learning strategy is presented to recursively estimate (i.e., track) the time-varying a priori distribution for a multivariate empirical Bayes adaptive classification rule. The problem is formulated by modeling the prior distribution as a finite-state vector Markov chain and using past decisions to estimate the time evolution of the state of this chain. The solution is obtained by implementing an exact recursive nonlinear estimator for the rate vector of a multivariate discrete-time point process representing the decisions. This estimator obtains the Doob decomposition of the decision process with respect to the a-field generated by all past decisions and corresponds …

Strategic Planning For Sponsored Projects Administration: The Role Of Information Management, Robert V. Williams

Faculty Publications

No abstract provided.

What Is “An Establishment Of Religion?", William W. Van Alstyne

Faculty Publications

No abstract provided.

Hard-Sphere Theory For Correlation Of Tracer Diffusion Of Gases And Liquids In Alkanes, Michael A. Matthews, Aydin Akgerman

Faculty Publications

No abstract provided.

The Political Environment Of Economic Planning In Iran, 1971-1983: From Monarchy To Islamic Republic, By Hossein Razavi And Firouz Vakil, Shahrough Akhavi

Faculty Publications

No abstract provided.

Tree Content And Taper Functions For Loblolly And Slash Pine Trees Planted On Non-Old-Fields In East Texas, J. David Lenhart, Terry L. Hackett, Charlie J. Laman, Thomas J. Wiswell, Jock A. Blackard

Faculty Publications

Equations are presented to estimate total or partial stem content in cubic feet and pounds (green or dry) for loblolly pine (Pinus taeda L.) and slash pine (Pinus elliotti Engelm.) trees planted on non-old-fields in East Texas. Equations are included to estimate the content of the complete tree (stem and branches). In addition, a set of compatible stem taper functions are described. South. j. Appl. For. 11(3):147-151

The Sharpness Of Some Cluster Set Results, D. Rung, Samih Obaid

Faculty Publications

We show that a recent cluster set theorem of Rung is sharp in a certain sense. This is accomplished through the construction of an interpolating sequence whose limit set is closed, totally disconnected and porous. The results also generalize some of Dolzenko's cluster set theorems.

Spoil Banks: Effects On A Coastal Marsh Water-Level Regime, Erick M. Swenson, R. Eugene Turner

Faculty Publications

Above- and below-ground water-level fluctuations were measured in the marshes south of New Orleans, Louisiana, between November 1982 and December 1983. The purpose of the program was to defme the basic marsh water-level regime and to investigate how canal spoil banks may influence the water-level regime. Two study areas were used: (1) a control area, defined as a section of marsh with unrestricted hydrologic connection to an adjacent bayou; and, (2) a partially-impounded area, defined as an area with limited hydrologic connection to an adjacent bayou due to the presence of dredged canal spoil banks. Data sources included marsh water …