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Chemical Engineering

Selected Works

1991

Articles 1 - 11 of 11

Full-Text Articles in Engineering

Polymer Research In Austria. I: Introduction And The Facilities, Otto Vogl, Josef Schurz, Bernd Thrattnigg, Klaus Hummel, Wolfgang Daimler, Klaus Lederer Dec 1991

Polymer Research In Austria. I: Introduction And The Facilities, Otto Vogl, Josef Schurz, Bernd Thrattnigg, Klaus Hummel, Wolfgang Daimler, Klaus Lederer

Otto Vogl

No abstract provided.

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Japan-U.S. Seminar On Polymer Synthesis, Otto Vogl, Hiroyuki Nishide Dec 1991

Japan-U.S. Seminar On Polymer Synthesis, Otto Vogl, Hiroyuki Nishide

Otto Vogl

No abstract provided.

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Modeling Electroplating Rinse Systems Using Equation-Solving Software, Andrew C. Hillier, Clifford W. Walton Oct 1991

Modeling Electroplating Rinse Systems Using Equation-Solving Software, Andrew C. Hillier, Clifford W. Walton

Andrew C. Hillier

Microcomputers are finding application in a vast array of academic and industrial settings, but are under-utilized in the electroplating industries. An often overlooked tool for computer simulation, for example, is equationsolving software. Such programs can predict the performance of a process system from basic mathematical relations without requiring the operator to have extensive knowledge of sophisticated programming and numerical solution techniques. A model of a multi-tank counter-current rinse system is described, then simulated with this software, and the results compared to actual plating facility rinse data, showing the excellent predictive qualities of this approach.

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Random Sequential Adsorption Of Parallel Squares, Benjamin J. Brosilow, Robert M. Ziff, R. Dennis Vigil Jan 1991

Random Sequential Adsorption Of Parallel Squares, Benjamin J. Brosilow, Robert M. Ziff, R. Dennis Vigil

R. Dennis Vigil

The random sequential adsorption of parallel (aligned) squares is studied by computer simulation. A new precise value of the maximum (jamming) coverage is found: I9J =0.562 009+0.000004. The dynamics for times t ~6000 agree with Swendsen s prediction 0J—0(t)-c(lnt)/t. Various twopoint correlation functions are measured, and the effects of the finite size and the discretization of the adsorbing surface are also investigated.

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Optimering Van Koagulasie En Flokkulasie In Die Herwinning Van Koelwater Uit Oliesintese-Afvalwater, Johannes Van Leeuwen, P. Wille Jan 1991

Optimering Van Koagulasie En Flokkulasie In Die Herwinning Van Koelwater Uit Oliesintese-Afvalwater, Johannes Van Leeuwen, P. Wille

Johannes van Leeuwen

The activated sludge process, which is used in the purification of an oil synthesis effiuent, produces an effiuent which is high in turbidity. The water also contains a lot of dispersed bacterial growth which is not removed during sedimentation. Flocculation is essential to remove these materials. The average diameter of the colloids was found to be 0,92/'m. The zeta potential of the colloids was determined in an attempt to correlate it to the amount of flocculant required. The value was relatively constant at -13,88 mV, which indicates that a cationic·coagulant was required. The required dosage to achieve clarification by means …

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72. Professor Cristofor I. Simionescu On His 70th Birthday, Otto Vogl, Ioan I. Negulescu Jan 1991

72. Professor Cristofor I. Simionescu On His 70th Birthday, Otto Vogl, Ioan I. Negulescu

Otto Vogl

No abstract provided.

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A Pairwise Interaction Theory For Determining The Linear Acoustic Properties Of Dilute Bubbly Liquids, Ashok S. Sangani Jan 1991

A Pairwise Interaction Theory For Determining The Linear Acoustic Properties Of Dilute Bubbly Liquids, Ashok S. Sangani

Ashok S. Sangani

The problem of determining the acoustic properties of dilute bubbly liquids is examined using the method of ensemble-averaged equations and pairwise interactions. The phase speed and attenuation of sound waves in the small-amplitude regime are determined as a function of frequency of sound waves including the effects of finite surface tension, small viscosity of the liquid, and non-adiabatic thermal changes, and compared with the experimental data available in the literature. An excellent agreement is found for frequencies smaller than about 1.3 times the natural frequency of the bubbles, but the discrepancy is substantial at larger frequencies.

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The Added Mass, Basset, And Viscous Drag Coefficients In Nondilute Bubbly Liquids Undergoing Small-Amplitude Oscillatory Motion, Ashok S. Sangani, D. Z. Zhang, A. Prosperetti Jan 1991

The Added Mass, Basset, And Viscous Drag Coefficients In Nondilute Bubbly Liquids Undergoing Small-Amplitude Oscillatory Motion, Ashok S. Sangani, D. Z. Zhang, A. Prosperetti

Ashok S. Sangani

The motion of bubbles dispersed in a liquid when a small-amplitude oscillatory motion is imposed on the mixture is examined in the limit of small frequency and viscosity. Under these conditions, for bubbles with a stress-free surface, the motion can be described in terms of added mass and viscous force coefficients. For bubbles contaminated with surface-active impurities, the introduction of a further coeflicient to parametrize the Basset force is necessary. These coefficients are calculated numerically for random configurations of bubbles by solving the appropriate multibubble interaction problem exactly using a method of multipole expansion. Results obtained by averaging over several …

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Fluorescent Molecular Probe Technique For Assessing The Interaction Between Sulfonated Polystyrene And Poly(Ethyl Acrylate-Co-4-Vinylpyridine) Ionomers In Tetrahydrofuran, William Macknight, Kirill N. Bakeev Dec 1990

Fluorescent Molecular Probe Technique For Assessing The Interaction Between Sulfonated Polystyrene And Poly(Ethyl Acrylate-Co-4-Vinylpyridine) Ionomers In Tetrahydrofuran, William Macknight, Kirill N. Bakeev

William MacKnight

The interaction between sulfonated polystyrene (SPS) and poly(ethy1 acrylate-eo-4-vinylpyridine)
(EtAc4VP) ionomers was investigated over a wide range of concentrations in the nonpolar solvent,
tetrahydrofuran (THF), using a fluorescent molecular probe technique. The acid-base interaction between
the sulfonate groups of SPS and the pyridine groups of EtAcVP and the miscibility of these ionomers are
evident for pyridine contents of 7.8 and 4.5 mol 5% in EtAc4VP and are not detectable for EtAc4VP with
1.7 mol % pyridine groups. Concentration-dependent excimer fluorescence from SPS and EtAc4VP mixtures
indicates the occurrence of polar interactions as a result of proton transfer from the styrenesulfonic …

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Mechanism Of The Dicyandiamide/Epoxide Reaction, William Macknight, Michael D. Gilbert, Nathan S. Schneider Dec 1990

Mechanism Of The Dicyandiamide/Epoxide Reaction, William Macknight, Michael D. Gilbert, Nathan S. Schneider

William MacKnight

A mechanism is proposed for the dicyandiamide (dicy) cure of epoxy resins based on the
analysis of products formed by the reaction of a monofunctional epoxide with dicy and with cyanamide.
Products were isolated from the uncatalyzed reaction mixtures using preparatory liquid chromatography and
were characterized by FTIR, NMR, mass spectrometry, and elemental analysis. Both linear dicy/epoxide
adducts and cyclical species were identified and the mechanism of the cyclization reaction was delineated.
A mechanism for carbonyl generation during the later stages of cure was also found.

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Thermal, Dielectric, And Mechanical Relaxation In Poly(Benzimidazole)/Poly(Etherimide) Blends, William Macknight, Kuiming Liang, Gyorgy Banhegyi, F. E. Karasz Dec 1990

Thermal, Dielectric, And Mechanical Relaxation In Poly(Benzimidazole)/Poly(Etherimide) Blends, William Macknight, Kuiming Liang, Gyorgy Banhegyi, F. E. Karasz

William MacKnight

Thermal, dielectric, and mechanical relaxation measurements on miscible blends of poly-
benzimidazole(PBI)and a polyetherimide (PEI, Ultem 1000)prepared by solution casting
from dimethylacetamide (DMAc) reveal a number of structurally related features. Annealing
below the glass transition temperature induces an enthalpy relaxation process typical of
single-phase glasses of nonequilibrium structure. Dielectric relaxation experiments on
samples annealed at ambient conditions reveal two relaxation processes below 400°C.At
lower temperatures (50-2OO0C), the desorption of water is observed. Above 200°C in the
first run, a composition-dependent relaxation is seen at the highest frequencies ( 100 kHz)
while a relaxation approximately independent of composition appears in the …

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