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Articles 1411 - 1429 of 1429

Full-Text Articles in Chemical Engineering

The Anodic Dissolution Of Tungsten, James W. Johnson, Cheng-Hsiao Wu Jan 1971

The Anodic Dissolution Of Tungsten, James W. Johnson, Cheng-Hsiao Wu

Chemical and Biochemical Engineering Faculty Research & Creative Works

The anodic dissolution of tungsten was studied in H2SO4-K2SO4 solutions (pH = -2 to 2.5) and K2SO4-K2CO3-KOH solutions (pH = 11.5 to 14.5) at 25 C. Faradaic efficiency studies in basic solutions showed the metal to be oxidized to the +6 state. In acid solutions, a thick protective film of yellow WO3 was formed. Polarization curves possessed linear Tafel regions (slope ~ 2.3 RT/F) at potentials slightly more positive than the rest potentials. An anodic dissolution mechanism is proposed which involves a surface film …

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Effects Of Molecular Characteristics Of Polymers On Drag Reduction, Gin‐Chain ‐C Liaw, Jacques L. Zakin, Gary Kent Patterson Jan 1971

Effects Of Molecular Characteristics Of Polymers On Drag Reduction, Gin‐Chain ‐C Liaw, Jacques L. Zakin, Gary Kent Patterson

Chemical and Biochemical Engineering Faculty Research & Creative Works

Turbulent measurements in capillary tubes and in pipes were made on nonpolar solutions of seven polymer species, three at more than one molecular weight, over wide concentration ranges. A critical concentration, Cc, was taken as the minimum concentration for disappearance of the turbulence transition region. Above this concentration, friction factor‐generalized Reynolds number data show only a gradual deviation from extension of the laminar line. Cc increases with tube diameter and decreases with molecular weight. The critical dimensionless volume friction Cc [η] is less dependent on molecular weight. The levels of Cc [η] for different polymer species in a given tube …

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Sufficiency Conditions For Constrained Optima, Ju-Chang Huang, Robert M. Wellek Jan 1971

Sufficiency Conditions For Constrained Optima, Ju-Chang Huang, Robert M. Wellek

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Sufficiency conditions for constrained optimization problems were derived by the use of constrained second total derivatives. The results are in a simpler form than the Schechter and Beveridge relation. The sufficiency conditions of Phipps were corrected. © 1971, American Chemical Society. All rights reserved.

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Drag Reduction Correlations, Gary Kent Patterson, J. L. Zakin, J. M. Rodriguez Jan 1970

Drag Reduction Correlations, Gary Kent Patterson, J. L. Zakin, J. M. Rodriguez

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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A Liquid Extraction Column With Reciprocated Wire Mesh Packing, Robert M. Wellek, M. Uran Ozsoy, J. J. Carr, Dudley Thompson, Thomas V. Konkle Oct 1969

A Liquid Extraction Column With Reciprocated Wire Mesh Packing, Robert M. Wellek, M. Uran Ozsoy, J. J. Carr, Dudley Thompson, Thomas V. Konkle

Chemical and Biochemical Engineering Faculty Research & Creative Works

In a new type of pulsating, liquid extractor, pulsating energy is added to the counter currently flowing liquid streams by a stainless-steel wire mesh packing which is reciprocated vertically in a 3-inch i.d. extraction column. The mass transfer performance and flooding characteristics are studied as a function of the frequency and amplitude of reciprocation, the total solvent and feed throughputs, and choice of phase dispersion. The benzene-HAc-H2O and MIBK-HAcH2O systems were used. Extraction data for the benzene system were correlated in terms of a dimensionless pulse velocity group. Operating throughputs are significantly higher than those achieved …

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Comparison Of Lagrangian Time Correlations Obtained From Dispersion Experiments And From Space‐Time Correlation Functions, J. M. Rodriguez, Gary Kent Patterson Jan 1969

Comparison Of Lagrangian Time Correlations Obtained From Dispersion Experiments And From Space‐Time Correlation Functions, J. M. Rodriguez, Gary Kent Patterson

Chemical and Biochemical Engineering Faculty Research & Creative Works

No Abstracts. Copyright © 1969 American Institute of Chemical Engineers

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Mass And Heat Transfer Relations In Evaporation Through Porous Membranes, Marshall E. Findley, V. V. Tanna, Y. B. Rao, C. L. Yeh Jan 1969

Mass And Heat Transfer Relations In Evaporation Through Porous Membranes, Marshall E. Findley, V. V. Tanna, Y. B. Rao, C. L. Yeh

Chemical and Biochemical Engineering Faculty Research & Creative Works

This study concerns rates of evaporation and mass transfer of water vapor from a heated salt solution through a water repellent porous membrane to a cooled water condensate. This transfer is a result of temperature differences and corresponding vapor pressure differences across the membrane. Three groups of experiments were carried out which indicate that the major factor influencing the rates of transfer is diffusion through a stagnant gas in the membrane pores. However, an equation considering film heat transfer coefficients, membrane thermal conductivity, and an empirical correction based on temperature driving force appears to be necessary for representing all the …

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Prediction Of Drag Reduction With A Viscoelastic Model, Gary Kent Patterson, J. L. Zakin Jan 1968

Prediction Of Drag Reduction With A Viscoelastic Model, Gary Kent Patterson, J. L. Zakin

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Numerical Differentiation Of Equally Spaced And Not Equally Spaced Experimental Data [3], Harry C. Hershey, Jacques L. Zakin Jan 1968

Numerical Differentiation Of Equally Spaced And Not Equally Spaced Experimental Data [3], Harry C. Hershey, Jacques L. Zakin

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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Existence Of Two Types Of Drag Reduction In Pipe Flow Of Dilute Polymer Solutions, Harry C. Hershey, Jacques L. Zakin Aug 1967

Existence Of Two Types Of Drag Reduction In Pipe Flow Of Dilute Polymer Solutions, Harry C. Hershey, Jacques L. Zakin

Chemical and Biochemical Engineering Faculty Research & Creative Works

Drag reduction in the pipe flow of polymer solutions is shown to be of two types which apparently occur by two separate mechanisms. In turbulent flow, drag reduction is probably caused by viscoelastic effects. The critical solvent Reynolds number at the onset of drag reduction is proportional to about the first power of the diameter. Thus, the critical velocity is independent of tube diameter. Polymers dissolved in good solvents show more drag reduction than in poor solvents. The other type of drag reduction occurs when the laminar region is extended to high Reynolds numbers. It is followed by a transition …

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Numerical Differentiation Of Equally Spaced And Not Equally Spaced Experimental Data, Harry C. Hershey, Jacques L. Zakin, Robert Simha Aug 1967

Numerical Differentiation Of Equally Spaced And Not Equally Spaced Experimental Data, Harry C. Hershey, Jacques L. Zakin, Robert Simha

Chemical and Biochemical Engineering Faculty Research & Creative Works

Procedures are given for smoothing and differentiating experimental data with both equal and nonequal spacing in the independent variable. Selection of the number of points to be included in the "movable strip" technique and of the degree of the polynomial is discussed. Equations are given to estimate the error by calculating a confidence interval on each slope. A technique for handling certain types of nonrandom errors is presented. © 1967, American Chemical Society. All rights reserved.

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Vaporization Through Porous Membranes, Marshall E. Findley Apr 1967

Vaporization Through Porous Membranes, Marshall E. Findley

Chemical and Biochemical Engineering Faculty Research & Creative Works

Mixtures may be evaporated from one interface of a Non wettable porous membrane with diffusion through the vapor-filled pores and condensation at the other interface of the membrane, by a sufficiently higher temperature on the mixture side maintained by a heat supply to the mixture and heat removal from the condensate equal to the latent heat transferred with vapor plus heat transferred by conduction. This permits essentially infinite-stage flash evaporation at constant liquid pressures, either with diffusion through Non condensable gases in the pores, or with vapor flow at a lower pressure than liquid pressures, but with liquids excluded from …

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Hot‐Film Anemometry Measurements Of Turbulence In Pipe Flow: Organic Solvents, Gary Kent Patterson, Jacques L. Zakin Jan 1967

Hot‐Film Anemometry Measurements Of Turbulence In Pipe Flow: Organic Solvents, Gary Kent Patterson, Jacques L. Zakin

Chemical and Biochemical Engineering Faculty Research & Creative Works

Longitudinal turbulence intensities, autocorrelations, and energy spectra have been measured in the flow of toluene, benzene, and cyclohexane in smooth, round 1‐ and 2‐in. I.D. tubes. These measurements were made with a constant‐temperature hot‐film anemometer and covered radial positions from the center to r/a = 0.85 in the 2‐in. tube and to r/a = 0.75 in the 1‐in. tube. The turbulence intensity data were found to be similar to those obtained for air in a 10‐in. pipe by Laufer. A slight diameter effect was observed, the intensities in the 1‐in. tube being slightly lower than those in the 2‐in. tube …

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The Mechanism Of The Electrooxidation Of Acetylene On Gold, James W. Johnson, J. L. Reed, William Joseph James Jan 1967

The Mechanism Of The Electrooxidation Of Acetylene On Gold, James W. Johnson, J. L. Reed, William Joseph James

Chemical and Biochemical Engineering Faculty Research & Creative Works

Acetylene has been oxidized anodically in aqueous solutions at 80 °C on gold electrodes. It was found that the partial oxidation to CO2 was accompanied by a polymer formation. Effects of potential, acetylene partial pressure, pH, and temperature on the rate (current) were measured. A discontinuity in the Tafel curves was noted that indicated a change in the reaction mechanism with potential. The discontinuity was also pH dependent. A mechanism involving the discharge of H2O and/or OH− has been proposed that is consistent with the experimental results. © 1967, The Electrochemical Society, Inc. All rights reserved.

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Radial Pressure Gradient In Turbulent Pipe Flow, Gary Kent Patterson, Walter J. Ewbank, Virgil A. Sandborn Jan 1967

Radial Pressure Gradient In Turbulent Pipe Flow, Gary Kent Patterson, Walter J. Ewbank, Virgil A. Sandborn

Chemical and Biochemical Engineering Faculty Research & Creative Works

Measurements made with a Prandtl static pressure probe have demonstrated that a radial pressure gradient does exist in turbulent pipe flow with approximately the magnitude predicted by Sandborn from hot-wire anemometry measurements.

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Handlos And Baron Model: Short Contact Times, J. Patel, Robert M. Wellek Jan 1967

Handlos And Baron Model: Short Contact Times, J. Patel, Robert M. Wellek

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

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The Anodic Dissolution Of Cadmium, James W. Johnson, E. Deng, S. C. Lai, William Joseph James Jan 1967

The Anodic Dissolution Of Cadmium, James W. Johnson, E. Deng, S. C. Lai, William Joseph James

Chemical and Biochemical Engineering Faculty Research & Creative Works

The anodic dissolution of cadmium has been studied in aqueous solutions containing Cl−, Br−, I−, Ac−, SO4=, and NO3− ions. The normal valence (+2) was found in all solutions with the exception of NO3−. The apparent valence (calculated) of cadmium ions in nitrate solutions varied from 1.2 to 2.0 and was found to be a function of NO3− concentration, current density, and temperature. An anodic dissolution mechanism has been proposed involving local corrosion and disintegration of the anode which is consistent with the experimental results. © 1967, The Electrochemical Society, Inc. All rights reserved.

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The Effect Of Concentration On The Viscosities Of Solutions Of Linear Flexible High Polymers, Lung Yu Chou, Jacques L. Zakin Jan 1967

The Effect Of Concentration On The Viscosities Of Solutions Of Linear Flexible High Polymers, Lung Yu Chou, Jacques L. Zakin

Chemical and Biochemical Engineering Faculty Research & Creative Works

Viscosity-concentration results in the moderately concentrated range for four samples of polyisobutylene (molecular weights of 1.3 x 104 to 1.0 x 106) in cyclohexane (concentrations up to 4.7 g./dl.) and in benzene (concentrations up to 7.0 g./dl.) at 24°C. (a theta solvent) showed molecular weight and goodness of solvent dependencies similar to those reported earlier for three other polymers. For polyisobutylene, polystyrene, and a copolymer of styrene and methyl methaerylate in good solvents, viscosity-concentration data plotted as ηsp. C[η] vs. k′[η]C fit a single curve. The linear region of this curve suggests that the Huggins equation is useful to C[η] …

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The Utilization Of Grapefruit Waste., Howard E. Bumsted 1917-1989 Jan 1940

The Utilization Of Grapefruit Waste., Howard E. Bumsted 1917-1989

Electronic Theses and Dissertations

No abstract provided.

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