Digital Commons Network^™

A Model Of The Bromine/Bromide Electrode Reaction At A Rotating Disk Electrode, Ralph E. White, S. E. Lorimer

Faculty Publications

A mathematical model is presented for the Br₂/Br^– electrode reaction at a rotating disk electrode. The model includes current density-overpotential expressions for the electrode reaction according to either the Volmer-Heyrovsky (V-H) or the Volmer-Tafel (V-T) mechanism and the transport equations including the effect of ionic migration. The model is used to predict current-overpotential curves for various cases of interest. Qualitative comparison of the model predictions to literature data shows that either the V-H or the V-T mechanism, with V controlling, may be acceptable for the Br₂/Br^– reaction.

Energy Storage Capacity Of Reversible Liquid‐Phase Diels Alder Reaction Between Maleic Anhydride And 2‐Methyl Furan, B. G. Sparks, Bruce E. Poling

Chemical and Biochemical Engineering Faculty Research & Creative Works

Calorimetry was used to determine the heat of reaction and equilibrium constant at 318 K for the reaction between maleic anhydride (A) and 2‐methyl furan (B). The values were −60 kJ/gmol and 614 cm3/gmol, respectively. The motivation for this work was to find a single phase‐reacting system that could be used to store solar energy. Thus, the energy storage capacity was calculated for a mixture of A and B, both initially at 7 kmol/m3, in dioxane. The maximum apparent heat capacity of 7.37 J/cm3·K occurred at 334 K. This maximum value is 76% higher than the heat capacity of pure …

An Analysis Of A Back Fed Porous Electorde For The Br2/Br- Redox Reaction, John W. Van Zee, Ralph E. White

Faculty Publications

No abstract provided.

Parallel Plate Electrochemical Reactor Model, Ralph E. White, Mike Bain, Mike Raible

Faculty Publications

No abstract provided.

Prediction Of The Current Density At An Electrode At Which Multiple Electrode Reactions Occur Under Potentiostatic Control, Ralph E. White, S. E. Lorimer, R. Darby

Faculty Publications

It is often desirable to be able to predict the total current density at an electrode when multiple electrochemical reactions occur there under potentiostatic control. It is also sometimes desirable to include the effect of ionic migration within the diffusion layer upon the predicted total (1) and partial current densities (2). A procedure for doing this can be illustrated by considering the rotating disk electrode (RDE) system and the associated potential distribution near the RDE as shown in Fig. 1 and 2.

An Analysis Of A Back Fed Porous Electrode For The Br2/Br Reaction, John Van Zee, Ralph E. White

Faculty Publications

An experimental analysis of the Br₂/Br^– redox reaction in a porous back fed ruthenium-coated titanium electrode is described. A mathematical model of the steady-state process is presented. Nonlinear regression of the model against the experimental data gives physically meaningful parameter estimates; these parameters and the model provide a design equation for the porous electrode current as a function of specific surface area, bulk Br₂ concentration, average total overpotential, and the Reynolds number. The design equation shows that the back fed electrode could reduce the loss of Br₂ across the separator and the ohmic loss in …

Motion Of Viscous Liquid In Rotating Cylinder, Chicheng Wu

Dissertations

A computer model for the withdrawl and buildup of the fluid from the pool bounded on the horizontal, rotating, cylindrical surface has been developed. For a incompressible Newtonian fluid, the model is based upon the modified SOLA-SURF algorithm to solve the finite-difference form of Navier-Stokes equations on primitive variables. A hybird of centered and partial donor cell differencings is applied to the momentum convective flux. In each time cycle, the cell velocity is adjusted by the pressure corrector and iterates to satisfy the equation of continuity. The free surface position is approximated by a surface height function derived from kinematic …

Production Of Anhydrous 1,4-Dioxane, Jean Yamanis

Chemical and Materials Engineering Faculty Patents

This invention relates to the production of anhydrous 1,4-dioxane by the dimerization of ethylene oxide in the presence of an acidic type of cation exchanger, preferably an acidic cation exchanger resin having sulfonic acid groups associated therewith. The 1,4-dioxane is formed by contacting ethylene oxide in the liquid phase with an acidic-type cation exchanger at a first temperature and for a time sufficient to yield a reaction product of the ethylene oxide and the cation exchanger, and thereafter heating the reaction product at a second temperature higher than the first temperature and for a time period sufficient to dissociate the …

Approximate Solutions For Distillation Rating And Operating Problems Using The Smoker Equations, Raymond C. Waggoner, Terry L. Tolliver

Chemical and Biochemical Engineering Faculty Research & Creative Works

Algorithms for rapid solution of implicit variables in the Smoker design equations are presented. The accuracy of these solutions in the context of distillation rating and operating problems Is evaluated for distillation systems where more rigorous physical property assumptions are known to apply. Alternative methods of initially fitting the Smoker equations to rigorous tray-by-tray material and energy balance calculations as well as methods extending the procedure to handle multicomponent systems are discussed. These methods are well suited for many optimization, reliability, and control studies as well as for the fast real-time calculations such as interactive computations or on-line control. © …

Fractionation Of Multicomponent Mixtures By Staged Sequence Cyclic Process And Parametric Pumping, Charles Omotayo Kerobo

Dissertations

The continuous fractionation of multicomponent fluid mixtures has been experimentally and theoretically investigated by staged sequence cyclic process and parametric pumping operating in the direct thermal mode.

A multicolumn staged sequence cyclic process for the separation of solute mixtures was developed. The criteria necessary for the continuous fractionation of a system of n solutes with n+1 columns arranged in a series operated with n+1 cyclic variables is presented. The feasibility for practical application of this process was demonstrated by fractionating the model system, O-xylene-Anisole-n-heptane on silica gel. The separation was modeled by one column staged sequence experimental data and by …

Separation Of Proteins Via Ph Parametric Pumping With Electric Field, Helen Conway Hollein

Dissertations

A new semi-continuous parametric pumping process for the separation of protein mixtures has been developed, based on cyclic variation of pH and electric field. The model system used for this process consisted of a mixture of human serum albumin and human hemoglobin in contact with CM Sepharose cation exchanger. Experimental results show that the protein separation via the pH parapump with electric field is two to three times greater than the results which are obtained in batch chromatography or via either single-column or multi-column parapumps with cyclic variation of pH and ionic strength.

The separation in the new process depends …

A Modified Unifac Model For The Prediction Of Henry's Constants, Carlos Alberto Marques Antunes

Theses

A group-contribution model for the correlation and prediction of Henry's constants in single solvents is presented. The mode: involves a one-parameter per gas/ solvent group pair UNIFAC expression extended to incorcorate free volume effects. The model is applied to three gases, CH₄, N₂, and O₂ in alkane solvents and in water. Good results, including a successful description of the temperature dependency of the Henry's constants, are obtained with typical accuracy of ± 10%.

The Diffusion Thermoeffect In Ternary, Nonelectrolyte Liquid Mixtures, Richard L. Rowley, Gerald Platt, Tevin Vongvanich

Faculty Publications

Expressions for that portion of the heat flux which is due to composition gradients in multicomponent nonelectrolyte liquid mixtures have been formulated in terms of heats of transport. The resultant thermal energy equation in combination with component mass balance equations constitute coupled partial differential equations descriptive of the diffusion thermoeffect in liquid mixtures. These equations were solved with a double perturbation technique subject to initial and boundary conditions consistent with experimental design conditions considered appropriate for successful measurement of multicomponent heats of transport. Based on the adiabatic type cell, the expected temperature response, dependent on cell variables, experimental conditions, and …

Diffusion Thermoeffect Measurements Of Heats Of Transport In Ternary Liquid Toluene Chlorobenzene Bromobenzene Mixtures At 25°C And 3°C, Richard L. Rowley, Gerald Platt, Tevin Vongvanich

Faculty Publications

Heats of transport in ternary nonelectrolyte liquid mixtures have been directly measured for the first time. Diffusion thermoeffect measurements have been made for ternary mixtures of toluene-chlorobenzene-bromobenzene at 25 degrees and 35 degrees C. A new boundary sharpening technique was used in addition to a liquid gate withdrawal method. Both techniques yield consistent, accurate values of the heat of transport, but the new cell provides versatility in allowable densities and compositions of the initial phases. Heats of transport were obtained by nonlinear least-squares fitting of calculated to experimental temperature differences measured at positions symmetric about the initial diffusional interface. The …

An Experimental Study Of Multiple Steady States In A Photopolymerization Reactor, Chih-Ning Kuan

Dissertations

An experimental study of photosensitized free radical polymerization of styrene in both batch and continuous stirred tank reactors is presented. Each reactor was run under both adiabatic and isothermal conditions. Multiple steady states were investigated. Exact multiplicity and uniqueness criteria for the above systems were derived and a mathematical model developed to correlate the results.

For both adiabatic and isothermal continuous stirred tank reactors operating in the metastable state regions, the conversion and polymer molecular weight are greater than the corresponding lower steady state operations. At a given conversion level, the reaction time for both adiabatic and isothermal continuous stirred …

The Entrainer Effect On Azeotropic Distillation Column Design, Charles Ming-Hsiao Tsai

Dissertations

A rigorous multistage distillation model was developed for use with non-ideal multicomponent systems. A subsidiary computer program was also developed to handle the problem of two liquid phases after condensation of a vapor.

Using the program developed, entrainer entry location and rate effects have been investigated via computer simulation for azeotropic distillation columns. The specific example used to verify the procedure was an ethanol dehydration column using benzene as the entrainer. The results indicate that the entrainer should enter the column two to five theoretical stages above the feed. The optimum entrainer rate was also determined.

The overhead vapor product …

Prediction Of Heats Of Mixing By Group Contribution Methods, William Walter Rupp

Theses

Three group contribution methods used to predict heats of mixing were tested: AGSM, UNIFAC with temperature dependent parameters and the modified UNIFAC of Skjold-Jor-gensen et al. The modified UNIFAC provided the best results and was adopted in this study. Primary parameters were obtained for ten groups with alkanes. The simultaneous correlation of cyclic and straight-chain alkanes gave poor results. Attempts to improve the error by changing the group area parameter for cyclic CH₂ failed.

A major problem in correlating the experimental data was the multiplicity of roots. The best set of parameters was obtained by using a grid approach …

Thermal Rearrangement Studies Of Deuterium Labeled Dibenzo [A,E] Cyclooctatetraenes, Charles W. Wenger

Theses

In an attempt to further substantiate the findings of Stiles and Salisbury on the rearrangement of aryl disubstiuted dibenzo [a, e] cyclooctatetraenes a new pair of derivatives were synthesized. The 5,6 and 5,11 dideuteriodibenzo-[a,e] cyclcoctetetraenes were prepared. The 5,6 derivative was prepared starting with dibenzo [a,e] cyclooctene-5,6-dione. The 5,11 derivative was prepared starting with o-tolualdehyde. In the case of the 5,6 derivative the deuterium was introduced by a LiAlD₄ reduction of the dibenzo [a,e]-cyclooctene-5,6-dione. The 5,11 derivative had been labeled with deuterium in the final step during the Wittig reaction. The use of methanol-d₁ as the solvent in …

Prediction Of Vapor-Liquid Equilibrium From Ternary Liquid-Liquid Equilibrium Data, David Kim Yee

Theses

Reasonable estimates of ternary vapor-liquid equilibrium can be obtained by using the corresponding liquid-liquid equilibrium (LLE) data with the NRTL, LEMF and UNIQUAC models. The overall average absolute deviation in vapor phase concentration for seven such systems is 0.028.: Use of the UNIFAC method gives erratic predictions suggesting caution when applied to such systems. Combination, however, of the LLE data and the UNIFAC method gives the best results with a deviation of 0.020 Prediction of binary VLE behavior from LLE data yields also reasonably good results.

Gaseous Reactions In Heteroporous Media, Elmer Anthony Klavetter

Doctoral Dissertations

"A modified dusty-gas model which accounts for the effects the pore-size and tortuosity distributions have on the mass fluxes in heteroporous media is presented. The behavior of the dusty-gas model (homoporous model) can be obtained from the modified model when the pressure is either very low or very high as well as for intermediate pressures when the characteristic parameter of the introduced tortuosity function has a very small value. When the pressure is very high or very low, all pores in the porous medium are almost in a single transport regime of either molecular or Knudsen diffusion.

Comparisons of the …

Analogy Among Heat And Momentum-Transfer For Non-Newtonian Fluids In Laminar-Flow Through Pipes, Bahman Ghorashi, Bela Hirsch

Chemical & Biomedical Engineering Faculty Publications

No abstract provided.

The Anodic Dissolution Of Zns Electrodes In Sulfuric Acid Solutions, Ram A. Narasagoudar, James W. Johnson, Thomas J. O'Keefe

Chemical and Biochemical Engineering Faculty Research & Creative Works

The anodic dissolution of reagent grade ZnS and ZnS concentrate has been studied. The majority of the research was conducted in H₂SO₄ although a limited number of tests were made in HCl and KOH. Polarization studies showed that both Zn²⁺ and S were products in the acidic solutions. ZnS passivated in KOH solutions. The electrodes were fabricated by hand pressing mixtures of ZnS + pitch (5-15%) and sintering at 800°C in a N2 atmosphere. The open circuit potentials were considered to be mixed potentials resulting from the anodic dissolution of ZnS and cathodic reduction of S …

Relative Volatilities Of The Ethane-Ethylene System From Total Pressure Measurements, David A. Barclay, Judith L. Fiebbe, David B. Manley

Chemical and Biochemical Engineering Faculty Research & Creative Works

A new apparatus has been developed for making vapor pressure measurements on high-pressure systems. Using this equipment, we have made a large number of new total pressure measurements on the ethane-ethylene binary from 198.15 to 278.15 K. By Integration of the general coexistence equation, relative volatilities have been calculated for ethane-ethylene over the entire temperature range. © 1982, American Chemical Society. All rights reserved.

Ethanol Densities Between −50 And 20 °C, Mark R. Schroeder, Bruce E. Poling, David B. Manley

Chemical and Biochemical Engineering Faculty Research & Creative Works

The density of ethanol was measured between −50 and 20 °C to ±0.01%. The measurements were made by using a procedure similar to ASTM D1217-54, "Standard Method of Test of Density and Specific Gravity of Liquids by Bingham Pycnometer". The results were correlated by the equation in D = −0.215231 − (1.05037 x 10−3)T − (7.837 x 10−7)T2 − (7.47 x 10−3)T3 (D in g/cm3, T in ° C). © 1982, American Chemical Society. All rights reserved.

Sequential Probability Ratio Tests For The Shape Parameter Of A Nonhomogeneous Poisson Process, Lee J. Bain, Max Engelhardt

Mathematics and Statistics Faculty Research & Creative Works

Sequential probability ratio tests for the shape parameter of one or more nonhomogeneous Poisson processes, with power intensity functions, are provided. The tests can be performed when the scale parameter is an unknown nuisance parameter; the effective loss of not knowing the scale parameter is one observation per process. The resulting tests can be expressed in terms of the maximum likelihood estimators of the shape parameters for the usual fixed sample procedure. A further advantage of the present approach is that the scale parameters for different processes, in the multiple sample procedures, need not be equal. Approximations for the operating …

Geotechnical Evaluation Of The Support Of Coal Pillars In Underground Coal Mines., John D. Rockaway, Richard W. Stephenson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Study Described Was Accomplished through an Investigation of Both the Intact and Insitu Geotechnical Properties of the Sub coal Strata and through the Installation of Floor Movement Monitoring Instrumentation. the Method of Bearing Capacity Analysis Developed by A. S. Vesic Was Used to Define Pillar Stability. This Method Includes Provisions for Taking into Consideration a Two-Layer System Such as Assumed for Mine Conditions Where a Weak Underclay overlies Firmer Strata.

Vapor Pressures Of Some C4 Hydrocarbons And Their Mixtures, Judith L. Flebbe, David A. Barclay, David B. Manley

Chemical and Biochemical Engineering Faculty Research & Creative Works

New experimental vapor pressures for the six binary systems containing 1,3-butadlene, n-butane, trans -2-butene, and c/s-2-butene at temperatures from 278 to 358 K are reported. Relative volatilities were calculated by using the Isothermal general coexistence equation. © 1982, American Chemical Society. All rights reserved.

An Applied Approach To Automatic Pressure Transient Analysis., Jeffrey Allan Joseph

Masters Theses

"A generalized digital approach to pressure transient (well-test) analysis is developed. The model is rigorously applicable to flow tests (pressure drawdown or injectivity of Newtonian liquids), and to pressure buildup or falloff tests provided the f low time prior to shut-in is large compared to the total shut-in time. However, buildup or falloff data may s till be analyzed if the above conditions are not satisfied, using the principles of superposition/desuperposition.

When plotted on logarithmic coordinates, pressure transient data generally assume a characteristic shape, indicative of flow behavior. Accurate computer analysis of this data requires its representation in concise mathematical …

Separation Technique On Proteins Via A Ph-Parametric Pump : A Theoretical And Experimental Study, Ura Pancharoen

Dissertations

The separation of protein mixtures via pH-parametric pumping was investigated both theoretically and experimentally. A simple system consisting of one column packed either with cation or anion exchanger was first considered. A system of parapumps was then developed with more columns which were connected in series and packed alternately with cation and anion exchangers. Various methods of operation of parapumps are discussed. Enrichment and spliting of protein mixtures were examined. In most cases, the separation factor was defined at a steady state condition and was improved by increasing the number of cycles and columns.

Computational methods for predicting both Batch …

An Experimental Study Of Comparison Between Ph-Parametric Pumping And Ph-Cycling Zone Adsorption Process On Protein Separation, Vincent P. Jajalla

Theses

In this thesis, an experimental investigation was conducted to compare the performance of the continuous pH-parametric pumping and the pH-cycling zone adsorption process on protein separation.

The model system studied was hemoglobin-water. on CM-Sepharose CL-6B (cation) exchanger in a single-column system. Various modes of operation were tried on both the pH-parametric pumping and the pH-cycling zone adsorption method. The separation factors for each mode of operation were computed and compared.

It is shown that the continuous pH-parametric pumping, with circulation to insure the pH uniformity inside the column, has the better separation factor than the pH-cycling zone adsorption method.