Engineering Commons^™

70. Obituary, Herman F. Mark, Otto Vogl

Otto Vogl

No abstract provided.

Royal Institute Of Technology: Department Of Polymer Technology, Otto Vogl, Ann Christine Albertsson

Otto Vogl

No abstract provided.

Polymer Science In Finland, Otto Vogl, Johan J. Lindberg, Franciska Sundholm

Otto Vogl

No abstract provided.

71. Otto Vogl, David A. Tirrell

Otto Vogl

No abstract provided.

Iupac Conference On “New Polymers”, Kyoto, Japan, Otto Vogl, Yoshiki Chujo

Otto Vogl

No abstract provided.

Second Pacific Polymer Conference In Otsu, Shiga, Japan, Otto Vogl, Tatsuki Kitayama, Koichi Hatada

Otto Vogl

No abstract provided.

The 33rd Iupac Congress, Budapest, August 17-22, 1991, Otto Vogl, Koichi Hatada

Otto Vogl

No abstract provided.

Tenth International Symposium On Cationic Polymerization And Related Processes, Otto Vogl, Gyorgy Deak

Otto Vogl

No abstract provided.

The Fokker–Planck Closure For Turbulent Molecular Mixing: Passive Scalars, Rodney O. Fox

Rodney O. Fox

A turbulent-molecular-mixing closure for passive scalar mixing is derived based on the theory of diffusion in layerlike lamellar structures. The closure is formulated in terms of the Fokker- Planck (FP) equation (or an equivalent stochastic differential equation), and is to be employed in conjunction with the probability density function (pdf) balance equation appearing in the pdf methods for modeling turbulent reactive flows. Like the mapping closure, the FP closure predicts a limiting Gaussian pdf for the passive scalar concentration in isotropic turbulence. In addition, the FP closure models the joint pdf of the scalar concentration and the scalar gradient and …

Spatial Variation Of A Short-Lived Intermediate Chemical Species In A Couette Reactor, R. Dennis Vigil, Q. Ouyang, Harry L. Swinney

R. Dennis Vigil

We have conducted experiments and simulations of the spatial variation of a short-lived intermediate species (triiodide) in the autocatalytic oxidation of arsenite by iodate in a reactor that is essentially one dimensional-the Couette reactor. (This reactor consists of two concentric cylinders with the inner one rotating and the outer one at rest; reagents are continuously fed and removed at each end in such a way that there is no net axial flux and there are opposing arsenite and iodate gradients.) The predictions ?f a one-dim~ns~onal . reaction-diffusion model which has no adjustable parameters, are In good qualItative (and, In some …

Effect Of Co2 On The Processing Of Y-Ba-Cu-O Superconductors, C. Zhang, Guna S. Selvaduray

Guna S. Selvaduray

The superconducting properties of YBa2Cu3O6+x reacted with various known ratios of O2/CO2 gas mixtures during sintering at different temperatures were studied. Jc was found to decrease drastically upon reaction with CO2, becoming zero at certain CO2 activities. The stability region for the 123 superconductor, as a function of CO2 activity and temperature, was empirically formulated as follows: log pCO2 < (−45,000)/T + 33.4. The grain boundaries in sintered samples with Jc = 0 were investigated with HRTEM in conjunction with EDS. Two distinct types of grain boundaries were observed. Approximately 10% of the grain boundaries were wet by a thin layer of a second phase, deduced to be BaCuO2. The remaining boundaries were sharp grain boundaries. The grain structure near the sharp grain boundaries was tetragonal. These two types of grain boundaries are thought to be responsible for Jc being zero.

Stochastic Modeling Of Turbulent Reacting Flows, Rodney O. Fox, J. C. Hill, F. Gao, R. D. Moser, M. M. Rogers

Rodney O. Fox

Direct numerical simulations of a single-step irreversible chemical reaction with non-premixed reactants in forced isotropic turbulence at Rx = 63, Da = 4.0, and Sc = 0.7 were made using 128 Fourier modes to obtain joint pdfs and other statistical information to parameterize and test a Fokker-Planck turbulent mixing model. Preliminary results indicate that the modeled gradient stretching term for an inert scalar is independent of the initial conditions of the scalar field. The conditional pdf of scalar gradient magnitudes is found to be a function of the scalar until the reaction is largely completed. Alignment of concentration gradients with …

Correlation Of Heat Of Mixing Data By The Nrtl And Uniquac Models. Part 2; Predictions Of Calorimetric Properties, Yasar Demirel, H.O. Paksoy, H. Gecegormez

YASAR DEMIREL

Here the parameters are employed to predict the calorimetric properties.

Scanning Electrochemical Mass Sensitivity Mapping Of The Quartz Crystal Microbalance In Liquid Media, Andrew C. Hillier, M. D. Ward

Andrew C. Hillier

The mass sensitivity distribution of the quartz crystal microbalance, denoted S(r,8), was determined in situ for pianopiano and plano-convex Aleut quartz resonators. The method involved measuring the frequency change associated with localized mass deposits created by electrochemical deposition using a scanning microelectrode in close proximity to the QCM eiectroded surface. Complete mathematical descriptions of S(r,8) were obtained from the measured data under conditions commonly encountered in QCM experiments. Our experimental resuits suggest that crystal contouring increases sensitivity toward the resonator center while reducing the extent of field fringing. Increaslng solution viscosity reduces the sensitivity to mass changes in the center …

Investigation Of A Monotropic Liquid Crystal Polyurethane Based On Biphenol, 2,6-Tolylene Diisocyanate, And A Six Methylene Containing Flexible Spacer. 1. Thermal And Structure Characterization, William Macknight, Fotios Papadimitrakopoulos, Shaw L. Hsu

William MacKnight

No abstract provided.

Investigation Of A Monotropic Liquid Crystal Polyurethane Based On Biphenol, 2,6-Tolylene Diisocyanate, And A Six Methylene Containing Flexible Spacer. 2. Ir Spectroscopic Phase Characterization, William Macknight, Fotios Papadimitrakopoulos, Eiji Sawa

William MacKnight

No abstract provided.

Polymer Miscibility In Capillaries, William Macknight, P. Cifra, F. E. Karasz

William MacKnight

Spectroscopic Study Of An Ionic Blend Made From The Acid Form Of Sulfonated Polystyrene And Poly[Ethyl Acrylate-Co-(4-Vinylpyridine)], William Macknight, Kazuo Sakurai, Elliot P. Douglas

William MacKnight

Thermal And Rheological Properties Of Miscible Polyethersulfone/Polyimide Blends, William Macknight, K. Liang, J. Grebowicz, E. Valles, F. E. Karasz

William MacKnight

Surface Segregation In Polymer Blends: A Monte Carlo Simulation, William Macknight, P. Cifra, F. E. Karasz

William MacKnight

Correlation Of Heats Of Mixing Data By The Nrtl And Uniquac Models. Part 1, Estimation Of The Model Parameters, Yasar Demirel, H. Gecegormez, H.O. Paksoy

YASAR DEMIREL

Using the data for heats of mixing, temperature dependent parameters of the NRTL and UNIQUAC models have been estimated for 57 systems of binary mixtures.

Calculation Of Excess Heat Capacities, Yasar Demirel, H.O. Paksoy

YASAR DEMIREL

Experimental data of excess heat capacities for 29 binary liquid mixtures of various types have been correlated by the NRTL and UNIQUAC models.