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Full-Text Articles in Engineering
Existence Of Two Types Of Drag Reduction In Pipe Flow Of Dilute Polymer Solutions, Harry C. Hershey, Jacques L. Zakin
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 …
Numerical Differentiation Of Equally Spaced And Not Equally Spaced Experimental Data, Harry C. Hershey, Jacques L. Zakin, Robert Simha
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.
Vaporization Through Porous Membranes, Marshall E. Findley
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 …
Hot‐Film Anemometry Measurements Of Turbulence In Pipe Flow: Organic Solvents, Gary Kent Patterson, Jacques L. Zakin
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 …
The Mechanism Of The Electrooxidation Of Acetylene On Gold, James W. Johnson, J. L. Reed, William Joseph James
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.
The Anodic Dissolution Of Cadmium, James W. Johnson, E. Deng, S. C. Lai, William Joseph James
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.
The Effect Of Concentration On The Viscosities Of Solutions Of Linear Flexible High Polymers, Lung Yu Chou, Jacques L. Zakin
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] …
Handlos And Baron Model: Short Contact Times, J. Patel, Robert M. Wellek
Handlos And Baron Model: Short Contact Times, J. Patel, Robert M. Wellek
Chemical and Biochemical Engineering Faculty Research & Creative Works
No abstract provided.
Radial Pressure Gradient In Turbulent Pipe Flow, Gary Kent Patterson, Walter J. Ewbank, Virgil A. Sandborn
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.