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Chemical Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

1998

Selected Works

Articles 1 - 11 of 11

Full-Text Articles in Chemical Engineering

Irreversibility Distribution For A Pure Convection Case Of The Smith-Hutton Problem, Yasar Demirel Dec 1997

Irreversibility Distribution For A Pure Convection Case Of The Smith-Hutton Problem, Yasar Demirel

YASAR DEMIREL

The irreversibility distributions for a pure convection heat transfer case of the Smith- Hutton problem have been calculated and displayed graphically. The steady state, twodimensional test problem of Smith-HuRon involves steep variations in temperature and strong streamline curvature in a rectangular flow domain that are encountered in many practical convection-diffusion problems. Combination of the first and second laws of thermodynamics has been utilized to calculate the irreversibility distribution ratio and the Bejan number with various degrees of steepness parameter in the temperature field. The shapes of the temperature and velocity profiles are the ones that maximize or minimize the total …

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Numerical Analysis Of Convection Heat Transfer In A Rectangular Packed Duct Withasymmetric Heating, Yasar Demirel, Y. Makkawi, H.H. Ali Dec 1997

Numerical Analysis Of Convection Heat Transfer In A Rectangular Packed Duct Withasymmetric Heating, Yasar Demirel, Y. Makkawi, H.H. Ali

YASAR DEMIREL

Fully developed, forced convection heat transfer in a rectangular packed duct is analyzed numerically based on a two-dimensional model incorporating the effects of Raschig ring packing on the Ergun equation. The boundary conditions are based on asymmetric heating with only the top wall supplied with a constant heat flux, while the other walls are adiabatic. The numerical predictions are compared with measured temperature profiles and local Nusselt numbers obtained from a large scale packed duct with L/H = 16 and W/H = 8, using Raschig rings of 4.8 cm in size. The prediction represents the experimental data satisfactorily. The volumetric …

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The Effect Of Temperature, Pressure And Ph On Biogas Methane Content From A Two-Stage Immobilized Cell Bioreactor, Michael Prince, A. Uppal Dec 1997

The Effect Of Temperature, Pressure And Ph On Biogas Methane Content From A Two-Stage Immobilized Cell Bioreactor, Michael Prince, A. Uppal

Michael J. Prince

No abstract provided.

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Phase Behaviour In Blends Of Poly[Styrene-Co-Ortho(Para)-Bromostyrene] And Phenylsulfonated Poly(2,6-Dimethyl-1,4-Phenylene Oxide) Copolymers, William Macknight, R. Vukovic, G. Bogdanic, A. Erceg, D. Fles, F. E. Karasz Dec 1997

Phase Behaviour In Blends Of Poly[Styrene-Co-Ortho(Para)-Bromostyrene] And Phenylsulfonated Poly(2,6-Dimethyl-1,4-Phenylene Oxide) Copolymers, William Macknight, R. Vukovic, G. Bogdanic, A. Erceg, D. Fles, F. E. Karasz

William MacKnight

Random copolymers of styrene with ortho- or para-bromostyrene differ substantially in their blend behaviour with partly sulfonylated poly(2,6-dimethyl-l,4-phenylene oxide) (SPPO). Copolymers of styrene with ortho­bromostyrene exhibit a very narrow window of miscibility in comparison with styrene-para-bromostyrene copolymer blends with SPPOs. The experimental results can be accounted for on the basis of individual segmental interaction parameters by applying mean-field theory.

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Thermally Stable Silphenylene Vinyl Siloxane Elastomers And Their Blends, William Macknight, H. Dennis Zhu, Simon W. Kantor Dec 1997

Thermally Stable Silphenylene Vinyl Siloxane Elastomers And Their Blends, William Macknight, H. Dennis Zhu, Simon W. Kantor

William MacKnight

No abstract provided.

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Water-Insoluble Complexes Of Poly(L-Lysine) With Mixed Alkyl Sulfates: Composition-Controlled Solid State Structures, William Macknight, Ekaterina A. Ponomarenko, David A. Tirrell Dec 1997

Water-Insoluble Complexes Of Poly(L-Lysine) With Mixed Alkyl Sulfates: Composition-Controlled Solid State Structures, William Macknight, Ekaterina A. Ponomarenko, David A. Tirrell

William MacKnight

Structures of the water-insoluble complexes of poly(L-lysine) with octyl and octadedecyl
sulfates, and with the mixtures of these surfactants, were examined via X-ray diffraction, infrared
spectroscopy, and differential scanning calorimetry. The solid-state structures of the complexes were
shown to be governed by their compositions. In the stoichiometric poly(L-lysine) complex with octadecyl
sulfate, surfactant chains crystallize on a hexagonal lattice. In the poly(L-lysine)-octyl sulfate complex
of nearly stoichiometric composition, the surfactants are arranged on an alkane-type two-dimensional
lattice. In the complex with 20 mol % octadecyl sulfate and about 75 mol % octyl sulfate, the longer
surfactant chains form hexagonal crystalline …

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Self-Assembled Polyelectrolyte-Surfactant Complexes In Nonaqueous Solvents And In The Solid State, William Macknight, Ekaterina A. Ponomarenko, David A. Tirrell Dec 1997

Self-Assembled Polyelectrolyte-Surfactant Complexes In Nonaqueous Solvents And In The Solid State, William Macknight, Ekaterina A. Ponomarenko, David A. Tirrell

William MacKnight

No abstract provided.

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Epitaxially Driven Assembly Of Crystalline Molecular Films On Ordered Substrates, Julie A. Last, Andrew C. Hillier, Daniel E. Hooks, Jeffrey B. Maxson, Michael D. Ward Dec 1997

Epitaxially Driven Assembly Of Crystalline Molecular Films On Ordered Substrates, Julie A. Last, Andrew C. Hillier, Daniel E. Hooks, Jeffrey B. Maxson, Michael D. Ward

Andrew C. Hillier

Crystalline, molecularly thick organic films mimicking layer motifs observed in bulk crystals of conducting (ET)2X charge-transfer salts (ET ) bis(ethylenedithiolo)tetrathiafulvalene, X ) I3, ReO4) form on highly oriented pyrolytic graphite (HOPG) electrodes upon electrochemical oxidation of ET in electrolytes containing I3 - or ReO4 - anions. The assembly of these molecular overlayers can be observed directly by in situ atomic force microscopy (AFM), and their structures can be deduced from lattice images obtained by AFM under growth conditions. AFM data reveal two different (ET)2I3 overlayers that are distinguished by the orientation of the ET molecules. One of these overlayers (type …

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Assessment Of Opacimeter Calibration On Kraft Pulp Mills, João F. Gomes Dec 1997

Assessment Of Opacimeter Calibration On Kraft Pulp Mills, João F. Gomes

João F Gomes

This paper describes the methodology and specific techniques for calibrating automatic on-line industrial emission analysers, specifically equipments that measure total suspended dust installed in pulp mills within the scope of Portuguese Regulation Nº 286/93 on air quality. The calibration of opacimeters is a multi-parameter relationship instead of the bi-dimensional calibration which is used in industrial practice. For a stationary source from a pulp mill such as the recovery boiler stack, which is subjected to significant variations, the effects of parameters such as the humidity and gas temperature, deviations on isokinetism, size range of particles and characteristic transmitance of equipment are …

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Two-Component Aerogel Adsorbents Of Water Vapour, J. Mrowiec-Bialon, A. B. Jarzebski, A. I. Lachowski, Janusz J. Malinowski Dec 1997

Two-Component Aerogel Adsorbents Of Water Vapour, J. Mrowiec-Bialon, A. B. Jarzebski, A. I. Lachowski, Janusz J. Malinowski

Janusz J. Malinowski

Two-component SiO2–CaCl2 or SiO2–LiBr aerogels exhibit outstanding adsorption capacities of water vapour, in the range of 0.9–1.1 kg H2O/kg adsorbent. Adsorption properties remain stable during repeated adsorptionrdesorption cycles

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Preparation Effects On Zirconia Aerogel Morphology, J. Mrowiec-Bialon, L. Pajak, A. B. Jarzebski, A I. Lachowski, Janusz J. Malinowski Dec 1997

Preparation Effects On Zirconia Aerogel Morphology, J. Mrowiec-Bialon, L. Pajak, A. B. Jarzebski, A I. Lachowski, Janusz J. Malinowski

Janusz J. Malinowski

Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) of zirconia aerogels’ morphology show a strong effect of the mode of supercritical drying on zirconia structure and a remarkable similarity of aerogels obtained using either acetic or nitric acid as process moderators. A fine polymeric structure in sub-nanometer scales and 20-nm polymeric aggregates were observed in aerogels obtained from the supercritical CO2 route. More massive polymeric structure in nanometer scales resulted from the standard high temperature process. Upon calcination at 773 K, all samples proved to be quite similar in morphology but a bit different in crystal structure.

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