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Articles 1 - 20 of 20
Full-Text Articles in Engineering
Polymer Science In Romania I: "Petru Poni" Institute Of Macromolecular Chemistry, Iasi, Romania, Otto Vogl, Cristofor I. Simionescu, Ioan I. Negulescu
Polymer Science In Romania I: "Petru Poni" Institute Of Macromolecular Chemistry, Iasi, Romania, Otto Vogl, Cristofor I. Simionescu, Ioan I. Negulescu
Emeritus Faculty Author Gallery
No abstract provided.
U.S.-Japan Seminar: "Synthesis, Properties And Reactions Of Specialty Polymers", Otto Vogl, Hiroshi Sumitomo
U.S.-Japan Seminar: "Synthesis, Properties And Reactions Of Specialty Polymers", Otto Vogl, Hiroshi Sumitomo
Emeritus Faculty Author Gallery
No abstract provided.
Polymer Science In Czechoslovakia Ii: Universities In The Czech Socialist Republic, Otto Vogl, Jaroslav Kralicek, Miroslav Schatz, Petr Vondracek
Polymer Science In Czechoslovakia Ii: Universities In The Czech Socialist Republic, Otto Vogl, Jaroslav Kralicek, Miroslav Schatz, Petr Vondracek
Emeritus Faculty Author Gallery
No abstract provided.
31st International Congress Of Pure And Applied Chemistry, Sofia, Bulgaria,1987, Otto Vogl, Ivan Shopov, Ivan Panayotov
31st International Congress Of Pure And Applied Chemistry, Sofia, Bulgaria,1987, Otto Vogl, Ivan Shopov, Ivan Panayotov
Emeritus Faculty Author Gallery
No abstract provided.
Iupac “Macro 87” In Merseburg (Gdr) Linking Tradition And Future In Polymer Science, Otto Vogl, Burkart Philipp
Iupac “Macro 87” In Merseburg (Gdr) Linking Tradition And Future In Polymer Science, Otto Vogl, Burkart Philipp
Emeritus Faculty Author Gallery
No abstract provided.
Periodic Solutions For Three Sedimenting Spheres, Ashok S. Sangani, Russel E. Caflisch, Chjan Lim, Jonathan H. C. Luke
Periodic Solutions For Three Sedimenting Spheres, Ashok S. Sangani, Russel E. Caflisch, Chjan Lim, Jonathan H. C. Luke
Biomedical and Chemical Engineering - All Scholarship
Exact periodic solutions are found for the relative motion of three spheres sedimenting in a Stokes fluid. Nearby solutions are found to be nearly periodic for a long time. Existence of the exact periodic solutions is proved using the point-particle approximation and symmetry properties of Stokes equations. Numerical simulations for finitie-sized particles are performed using a method of multipole expansions.
Transport Processes In Random Arrays Of Cylinders. Ii. Viscous Flow, Ashok S. Sangani, C. Yao
Transport Processes In Random Arrays Of Cylinders. Ii. Viscous Flow, Ashok S. Sangani, C. Yao
Biomedical and Chemical Engineering - All Scholarship
A numerical method is developed that takes into account the many-particle interactions in a rigorous manner to determine the effective thermal conductivity Km of a composite medium consisting of parallel circular cylinders of thermal conductivity ak suspended in a matrix of conductivity k. Numerical results for Km are presented for a wide range of a and o, the area fraction of the cylinders, after averaging over several computer-generated random arrays of cylinders. The results obtained via this exact method are compared with those of various approximate analytical methods to assess their utility in predicting Km.
Transport Processes In Random Arrays Of Cylinders. I. Thermal Conduction, Ashok S. Sangani, C. Yao
Transport Processes In Random Arrays Of Cylinders. I. Thermal Conduction, Ashok S. Sangani, C. Yao
Biomedical and Chemical Engineering - All Scholarship
A numerical method is developed that takes into account the many particle interactions in a rigorous manner to determine the effective thermal conductivity of Km of a composite medium consisting of parallel circular cylinders of thermal conductivity ak suspended in a matrix of conductivity k. Numerical results for Km are presented for a wide rane of a and o, the area fraction of the cylinders, after averaging over several computer-generated random arrays of cylinders. The results obtained via this exact method are compared with those of various approximate analystical methods to assess their utility in predicting Km.
Improved Streamline-Generating Technique That Uses The Boundary (Integral) Element Method, Daopu Thompson Numbere, D. Tiab
Improved Streamline-Generating Technique That Uses The Boundary (Integral) Element Method, Daopu Thompson Numbere, D. Tiab
Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works
The boundary element method (BEM) has been used to generate streamlines for homogeneous and sectionally homogeneous reservoirs having irregular boundaries. This technique is superior to earlier methods that use 'image wells' to simulate the reservoir boundary, especially for cases where the reservoir boundary is irregularly shaped. It has wider applicability to different kinds of reservoirs and eliminates the need for trial-and-error solutions. The errors caused by discretization and numerical approximation arise on and adjacent to the boundaries only, therefore the pressures and pressure gradients on which the streamlines are derived can be calculated with very high accuracy in the interior …
Analysis Of Electrokinetic Data By Parameter Estimation And Model Discrimination Techniques, Prosper K. Adanuvor, Ralph E. White
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.
Oxygen Tension Profiles In Tumors Predicted By A Diffusion With Absorption Model Involving A Moving Free Boundary, B. H. Arve, Athanasios I. Liapis
Oxygen Tension Profiles In Tumors Predicted By A Diffusion With Absorption Model Involving A Moving Free Boundary, B. H. Arve, Athanasios I. Liapis
Chemical and Biochemical Engineering Faculty Research & Creative Works
The dynamic behavior of the oxygen tension distribution in tumors during radiotherapy is studied by the development and solution of a diffusion with absorption model involving a moving free boundary. The oxygen uptake rates within the tumor are considered to be functions of the oxygen concentration and results are presented for zeroth-, half-, first- and second-order rates of absorption, as well as when the rate of oxygen absorption is described by the Michaelis-Menten expression. The results presented in this work may be used together with the data from the oxygen radiosensitivity curve of a tumor, in order to determine the …
Oxygen Reduction On Silver In 6.5 Molar Caustic Soda Solution, Prosper K. Adanuvor, Ralph E. White
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
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.
A Mathematical Model For Predicting Cyclic Voltammograms Of Electronically Conductive Polypyrrole, Taewhan Yeu, Trung V. Nguyen, Ralph E. White
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
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.
Secondary Current Distributions Using Topaz2d And Linear Kinetics, E. C. Dimpault-Darcy, Ralph E. White
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.
A Mathematical Model For The Electrodeposition Of Alloys On A Rotating Disk Electrode, Shiuan Chen, Ken-Ming Yin, Ralph E. White
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.
Oxygen Reduction On Silver In 6.5m Caustic Soda Solution, Prosper K. Adanuvor, Ralph E. White
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 …
Electrochemical Production And Corrosion Testing Of Amorphous Ni-P, Jose L. Carbajal, Ralph E. White
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. …
Electrodeposition Of Copper-Nickel Alloys From Citrate Solutions On A Rotating Disk Electrode, Ramona Y. Ying, Patrick K. Ng, Z. Mao, Ralph E. White
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 …