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• Articles  (7,661)
• Chemistry  (7,661)
• 1975-1979  (3,936)
• 1970-1974  (3,725)
• Process Engineering, Biotechnology, Nutrition Technology  (7,661)
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• Articles  (7,661)
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• 1
Electronic Resource
Weinheim : Wiley-Blackwell
Propellants, Explosives, Pyrotechnics 4 (1979), S. 115-120
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The synthesis of 2,2′,4,4′,6,6′-hexanitrostilbene by oxidative coupling of 2,4,6-trinitrotoluene in the presence of metal catalysts has been studied. The effects of reaction parameters on product yields have been evaluated and mechanisms for the reaction are proposed.
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• 2
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Weinheim : Wiley-Blackwell
Propellants, Explosives, Pyrotechnics 4 (1979), S. 129-131
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The production of HMX/Al 70/30 and the investigation of the characteristic properties are described and a comparison to RDX/Al 70/30 properties made. According to first test results, the possibility of an increased performance compared to RDX/Al 70/30 may not be ruled out.
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• 3
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Weinheim : Wiley-Blackwell
Propellants, Explosives, Pyrotechnics 4 (1979), S. 132-136
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The effect of fine (5 μm) and coarse (95 μm) aluminum on the deflagration-to-detonation transition (DDT) behavior of HMX, in charges pressed to 90% theoretical maximum density (TMD), was studied. It was found that Al slows down the DDT process increasingly as the content of Al increases; that is, it increases predetonation column length and the relative times to detonation. Fine Al is more effective than coarse in delaying DDT, at a given content, but both are inferior to wax in this respect.
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• 4
Electronic Resource
Weinheim : Wiley-Blackwell
Propellants, Explosives, Pyrotechnics 4 (1979), S. 121-128
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Dans cet article, nous avons étendu aux esters nitriques l'étude de la relation entre structure électronique et sensibilité au choc, déjà effectuée sur les nitroaromatiques et les nitramines. On y vérifie la validité du critère moléculaire de sensibilité au choc précédemment établi. Ce travail permet, en outre, de proposer une échelle de sensibilité au choc englobant les explosifs organiques des primaires aux secondaires les moins sensibles.
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• 5
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Weinheim : Wiley-Blackwell
Propellants, Explosives, Pyrotechnics 4 (1979), S. 136-138
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 6
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Expansion of TATB is studied on a molecular level by means of x-ray crystallography. Continuous monitoring of the cell constants of TATB between 214 K and 377 K allows calculation of a volume change of +5.1% for this molecular system. Expansion of the pure material is almost exclusively a function of a 4% linear increase in the c axis (the perpendicular distance between sheets of hydrogen-bonded TATB). Calculated from these data, the volume coefficient of thermal expansion for crystalline TATB is 30.4 × 10-5 K-1. The structural features of crystalline TATB and its anisotropic thermal-expansion behaviour are compared with those of graphite and boron nitride. Two other crystalline products in the bulk TATB are either actual polymorphs of TATB or impurities.
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• 7
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A new method for cast-loading of explosive charges is described. Up to now cooling was used to solidify the melt of the explosive. In this method the state of the explosive is changed by applying pressure which causes an immediate rise of the melting point according to Clausius-Clapeyron's equation. The total melt solidifies immediately and uniformly. The method has the advantage that voids are avoided and short loading times are obtained if the melting point is raised in this manner to the temperature momentarily present in the explosive.
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• 8
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A rapid method for simultaneous determinations of nitroguanidine and nitrate ion in the spent sulfuric acid has been developed. This method consists of merely diluting an aliquot of sample with water and measuring the absorbances of nitroguanidine and nitrate ion at 265 nm and 203 nm, respectively. In the concentration ranges studied, average accuracies of better than 1% and 2% were obtained for nitroguanidine and nitrate ion, respectively. The precision was better than 1% in both cases.
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• 9
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 10
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 11
Electronic Resource
Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 12
Electronic Resource
Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The performance of an explosive is a function of both the peak energy released near the detonation front, and the remainder of the energy that is released during the Taylor wave. The relative partitioning of energy between the front and the expansion, and the rate of energy release in the latter, may be controlled by either chemical kinetic or diffusion processes. Detonation calorimetry has been the principal experimental technique used to investigate these processes. Both the total energy release, and the quantitative analysis of the detonation products at a point or region on the expansion isentrope have been determined for formulations of ammonium nitrate (AN) and TNT in which both the composition and particle size of the AN have been varied. Isotopic labeling of selected explosives has also been used to give further insight into the reactions taking place in or near the reaction zone. Similar experiments have been performed in an ideal, homogeneous explosive.
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• 13
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A given formulation of a composite explosive was submitted to accelerated aging at 293 K, 333 K and 353 K for slightly over a year. Extensive determination of mechanical properties were conducted using an Instron Tester to characterize the aging process of the explosive as a whole. The change of elongation at maximum load can be fitted to a third-order reaction rate giving an enthalpy of activation (Δ Ha) for the aging process of (78 ± 5) kJ/mol. Although the change of stress at maximum load was a function of temperature, it could not be predicted by a simple correlation. Swelling, inverse gas chromatography and N2O evolution by infrared were applied to the samples aged at 333 K. Swelling measurements show a regular increase with aging of the relative number of cross-linking. Inverse gas chromatography at 373 K in helium indicated a first-order kinetic aging process for every sample, but the rate constant (k) of the samples aged for 0, 30 and 60 days was slightly lower than the one for samples aged for 130, 250 and 375 days. The N2O evolution measured at 338.5 K in vacuum by infrared absorption indicates an aging process consisting of two consecutive first-order reactions, the second one being ten times slower than the first one. The first stage, which was also studied by inverse gas chromatography, gives rate constants which are about half as large as those measured by chromatography and confirms the changes in behavior from the samples aged for 0, 30 and 60 days to the samples aged for 130, 250 and 375 days. These results are discussed in relation to an aging process by oxidative cross-linking of the binder and degradation of the solid explosive.
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• 14
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The problem of crack growth in a nitrocellulose/nitroglycerin propellant has been studied employing a continuum fracture mechanics approach. Values of the stress-intensity factor, Kc, at the onset of crack propagation have been ascertained and found to be dependent upon both the thickness of the specimen and the test temperature. By proposing that the value of Kc arises from the sum of a plane-strain and a plane-stress component a unique failure criterion, which is constant over a wide temperature range, has been identified. Namely, that crack propagation in the propellant occurs when the plane-stress plastic-zone at the crack tip attains a critical size.
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• 15
Electronic Resource
Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: n-Hexylcarborane (NHC) is the proposed burning rate modifier for improved propellants to be used in the next generation of missiles. The synthesis of this material requires decaborane-14, a material that is not commercially available in large quantities now. Therefore, the cost-effectiveness of synthesized NHC, as it relates directly to the missile cost, depends upon a low-cost synthesis of decaborane-14. Laser induced chemistry, a revolutionary new kind of chemistry, offers a much more efficient and less expensive way to synthesize compounds than conventional thermochemistry provides. Using this technique, we have synthesized decaborane-14 from diborane in high yields and high purity using both CO2 and DF laser frequencies. The products are decaborane-14 formed as white crystals and pentaborane-9 in the gaseous state; thus, isolation of the decaborane-14 is a simple chemical engineering procedure.
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• 16
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Thermal decomposition studies on double-base propellants have been carried out in air and vacuum using differential scanning calorimetric, thermogravimetric and mass spectrometric techniques. Low temperature (90 °C-170 °C) decomposition seems to involve diffusion controlled process, the mechanism in air and vacuum being different. High temperature (170 °-205 °C) decomposition involves bond breakage.
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• 17
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 18
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 19
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 20
Electronic Resource
Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 21
Electronic Resource
Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Optical properties of small droplets of aqueous solutions of zinc chloride were studied in the 3 μm to 12 μm spectral range. The droplets are generated by combustion of a pyrotechnic screening smoke composition containing hexachloroethane and zinc. Mass extinction coefficients were determined and interpreted by the theory of Mie.The optical constants of aqueous solutions of zinc chloride are markedly different from those expected for a screening smoke of low IR transparency.
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• 22
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Weinheim : Wiley-Blackwell
ISSN: 0721-3115
Keywords: Chemistry ; Polymer and Materials Science
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: It was found that the breakup-time of jets formed by shaped charges of cylindrical symmetry is given very accurately by the formula: \documentclass{article}\pagestyle{empty}\begin{document}$${\rm t}_{\rm B} {\rm = }\frac{1}{{{\rm V}_{{\rm PL}} }}\sqrt {8{\rm R } \cdot {\rm T}_{\rm L} } \cdot \sin {\rm \beta /2}$$\end{document} This formula is obtained from a general principal applied here for the first time which says that the breakup-time of homogeneous ductile metals under very high strain rates is equal to the smallest initial dimension of the elongating metal divided by VPL. When applied to simple configurations such as a pipe which expands due to internal explosion this principal leads to a correct prediction of the average formed fragment dimensions. This principal provides for the first time an explanation to the experimental fact that metals' ductility can increase by an order of magnitude when the strain rate increases from 10-2 to 105 pro second.
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• 23
Electronic Resource
Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979)
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 24
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 41-47
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: In a Lagrangian frame of reference based on lamina (fluid filament) thickness and in a warped time scale based on a single, flow dependent quantity, mixing, diffusion, and reaction can be described in a relatively simple way. Applications are presented for stretch and fold in taffy pull, egg beater and static mixer, shear stretch, stretch of laminae in a vortex, mixing with diffusion, reaction rate controlled by diffusion of reactant through a product layer, and very fast reactions in a turbulent flow.
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• 25
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 48-56
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: This paper is an experimental and theoretical study of horizontal stratified gas-liquid two phase flow in a circular tube. Both phases are considered to be in turbulent flow, and the liquid phase flow field is modeled by applying eddy viscosity expressions developed for single phase flow. The pressure drop and in situ volume of liquid are predicted from the gas and liquid flow rates, physical properties, and pipe size by means of an iterative procedure which terminates when calculated gas and liquid pressure drops match. The iterative design procedure is compared with new data for air-water flow in a smooth tube of 63.5 mm ID and with data available in the literature. For conditions corresponding to small amplitude interfacial waves, the average deviation between predicted and experimental results is 24.3% for the pressure drop and 7.7% for the holdup. For roll wave conditions, the corresponding average deviations are 4.6 and 26.4% for pressure drop and holdup, respectively. These results are substantially better than the predictions obtained using the Lockhart-Martinelli correlations.
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• 26
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 87-100
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The operation of two arrangements of multistage adsorption beds, parallel and series, was analyzed, and the optimal design problem of minimizing the capital and operating costs of the multistage adsorption bed systems was formulated. Solution of the optimization problem was obtained by using the Fibonacci search scheme. For the purpose of the study, data on the adsorption of liquid on activated carbon were taken from the literature for both single solute and multisolute adsorption systems and was used to derive the expressions for adsorption rate and the equilibrium relationship. Details of the performance of the optimally designed multistage adsorption bed systems are presented in terms of the physical and design parameters.
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• 27
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 100-108
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: This paper examines the effect of flow maldistribution on the predicted conversion and selectivity in a radial flow fixed-bed reactor. A simple model was developed to relate gas maldistribution to the catalyst bed to the conversion with first- and second-order reactions and to selectivity for first-order reactions in series and parallel. For the cases considered, the conversion debit due to maldistribution of the gas phase was as much as 11%. The model was extended to cover adiabatic conditions for simple first-order reactions. For an exothermic reaction, maldistributions can enhance conversion over that obtained with a uniformly distributed gas phase.
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• 28
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 24-32
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Two time delay compensation techniques, the Smith predictor and the analytical predictor, are used for bottom composition control of a pilot scale methanol-water distillation column. The closed-loop performance of the two predictor schemes is compared to that for a proportional-integral controller in experimental and simulation studies. The predictors resulted in improved control for both set point and feed flow disturbances.
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• 29
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 57-64
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Microscopic observations and Coulter counter measurements of the secondary nuclei produced when a parent crystal of potash alum was contacted with a solid rod suggest that these nuclei are born by an attrition mechanism which appears to be dependent on the growth rate of the crystal. The nuclei can be up to 50 μm in size. The nuclei smaller than about 4 μm are relatively insensitive to supersaturation, whereas the number greater than about 4 μm is approximately linear in supersaturation.
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• 30
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 131-143
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The hydrodynamic behavior of paper pulp slurries in vertical laminar flow has been observed and modeled. Radiotracers were used to tag both the liquid and solid phases of slurries flowing in 4 and 30 cm pipes. Residence time distributions were determined for each phase and were used to derive and compare several flow models. A model consisting of a central core in plug flow circumscribed by a clear Newtonian annulus provides a good representation of the observed slurry behavior. Correlations between the model parameters and the Reynolds number and slurry consistency are presented, and implications of the results on the design of slurry flow reactors are discussed.
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• 31
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 152-159
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: For every viscoelastic fluid studied in the contraction geometry, it was found that increasing the flow rate beyond a certain limit resulted in disturbance to the stable entry flow patterns described in Parts I and II. An examination of the development of the entry flow disturbances was carried out using still and cine photography. Still photographs are presented to illustrate the characteristics of the unstable flow patterns. The time varying nature of the flow has been recorded on a cine film Flow Patterns in Abrupt Entry Flow of Viscoelastic Fluids which is available for loan. Critical condition criteria for the onset of the periodic flow disturbances were obtained in terms of the fundamental fluid properties and are presented and compared with other suggested criteria for the onset of unstable entry flow of viscoelastic fluids.
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• 32
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 170-179
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A theoretical investigation of ultrafiltration through hollow fibers used in artificial kidney applications is presented. The hollow fibers are considered to be cylindrical tubes with ideally selective semipermeable walls which retain cellular particles (red and white cells, platelets) and plasma proteins in the blood perfusing the fibers. In contrast, water and species of low and medium molecular weight can freely permeate the membranes. The assumption is made that secondary flows avoid the formation of concentration boundary layers at the wall. Proper nondimensionalization of the equations for axial and radial transport results in the identification of parameters which are important in the characterization of the ultrafiltration through semipermeable tubes. Perturbation analyses for small values of these parameters lead to sets of differential equations which were solved analytically. These closed form solutions demonstrate the influence of hydraulic conductivity of the fiber walls, geometry, and axial and transmembrane pressure drop on the efficiency of hollow fiber artificial kidneys.
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• 33
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 190-192
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 34
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 206-206
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 35
Electronic Resource
Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979)
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 36
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 258-266
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The equation of motion for the two phase flow within a bubble column, operated within the recirculation flow regime, has been solved, and the profile of liquid flow has been determined. Nicklin's relation for the bubble flow regime has been extended to the recirculation flow regime.Data analysis shows that the mean slip velocity between bubble and liquid is approximately constant and that the kinematic turbulent viscosity increases rapidly with increasing diameter of the column. These observations lead to the conclusion that scale-up has but little influence upon the mean gas holdup.
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• 37
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 272-283
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Rates of hydrogenation of α-methyl styrene were measured at 40.6°C and 1 atm in a recycle, trickle-bed reactor using a palladium/aluminum oxide catalyst. Data for different hydrogen concentrations in the gas and liquid feed streams suggested that except, at high liquid flow rates, on part of the outer surface of the catalyst the mass transfer limitation was very small, indicating a gas covered type of surface. A procedure was developed for evaluating effectiveness factors for the nonuniform boundary conditions existing when part of the particle surface is covered by gas.
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• 38
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 306-311
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Removal of sulfur, nitrogen, and oxygen from heavy gas oils is affected by the chemical composition of supported molybdate catalysts. Cobalt and nickel, when added to these catalysts, have a promoting effect on these reactions. However, the relative rates always follow the same trend; that is, the hydrodesulfurization is the fastest, followed by hydrodenitrogenation and hydrodeoxygenation.
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• 39
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 320-327
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Continuous pH parametric pumping separations of a haemoglobin-albumin-CM Sepharose system were experimentally investigated. The parapump has a feed containing the protein mixture to be separated, introduced alternately to the top and bottom of the chromatographic column. The top and bottom products are withdrawn from the apparatus, respectively, during the bottom and top feed. It is shown that under certain conditions the pH driven parametric pump has the capacity for removal of protein components from one product fraction and large enrichment in the other fraction. Moreover, the continuous process can be operated with a large feed throughput.
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• 40
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 549-551
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 41
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 202-202
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 42
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 207-208
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 43
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 362-365
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 44
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 370-373
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 45
Electronic Resource
Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 376-381
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A new solution is obtained to the kinetics of a fixed-bed adsorber in response to a step change in feed concentration for a linear equilibrium system with consideration for the resistance to mass transfer in both the mobile and stationary phases. The differential equations of continuity and mass transfer are integrated upon simulating the intraparticle concentrations with a parabola. The results agree with Rosen's rigorous but complex solution in the range of conditions of practical interest. The present solution is more convenient for computer application for the calculation of breakthrough curves.
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• 46
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 384-384
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 47
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 385-395
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: A simulation procedure for predicting the dynamic behavior of a deep bed filter over the entire practicable range of filter operation is developed. The method is based on synthesizing available quantitative results relating to filtration, and to porous media flows, within an overall framework which views the process to consist of two principal stages dominated by appropriate limiting deposition modes. Evaluation of the results through comparison with available data indicates, to the extent the nature of these types of data permits, that the method is surprisingly effective and even capable of predicting on satisfactorily quantitative basis some intricate details of observed filter behavior.
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• 48
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 423-429
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Starting from a conventional distillation system without heat integration, a series of bottlenecks from the viewpoint of energy conservation is sequentially found by a thermodynamic analysis using a heat availability diagram, and modified systems are evolutionally synthesized as the result of debottlenecking. The present approach has made possible a unified interpretation of various energy integrated distillation systems with multieffect columns, intercondensers/interreboilers, heat pumps, etc.
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• 49
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 439-446
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Data on the ice formation rate are presented for a salwater drop suspended by drag forces in a flowing cold organic liquid. The effects of refrigerant undercooling, salt concentration, drop size, and time were studied. Ice formation rates in drops of 3 wt % sodium chloride solution were two to three times lower than in pure water drops. A parallel plate model was used to correlate the data and predict ice formation rates for other drops and refrigerants.Dispersing drops of brine or fruit juices in a countercurrent cold organic refrigerant is a method of desalination (or freeze concentration) that deserves further study.
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• 50
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 352-354
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 51
Electronic Resource
Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 358-359
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 52
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 365-367
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 53
Electronic Resource
Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 373-376
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 54
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 382-383
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 55
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 383-383
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 56
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 405-415
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The turbulence intersities and spectra in water very close to an air interface have been measured with a hot wire anemometer. The turbulence in the water has been induced in three ways: with a stirrer, by a submerged jet, and by flow of a thin film of water over inclined plates, both rough and smooth.We find that the root-mean-square fluctuation velocity Ṽx′ shows for the first system no regular trend with the distance y below the surface, while for the second system Ṽx′ increases markedly as the surface is approached. In water films over the rough plates, Ṽx′ can be as high as four times the shear stress velocity.The turbulence energy spectra close to the surfaces in the first and second systems show (Figure 6) no extended region of slope -5/3, whereas for flow over the plates, there is an appreciable subrange of this slope (Figures 8 and 9).Intensities of turbulence in the surface region are as high as 30 to 50% in the first system, up to 100% in the second system, and 17% over smooth plates and up to 60% over rough plates.These turbulence characteristics can be related to the rates of mass transfer for oxygen absorbing into water by comparing plots of k/D1/2 with the square roots of the different eddy frequencies. The Levich treatment [interpreted by Equation (15)] gives good agreement with the stirred cell and jet results. For the smooth and rough plates, mass transfer depends on eddies intermediate in size between the x directional and the y directional large eddies. In all cases, the Kolmogoroff eddy frequencies are much too high to correlate with mass transfer rates.Further, the energy spectra show that 60 to 80% of the total eddy energy lies in the larger eddies, with only 1% (or less) in the Kolmogoroff range.We conclude that the Prandtl sized eddies, and even larger eddies, determine mass transfer rates at a free surface.Direct measurement of concentration fluctuation frequencies, using platinum microelectrodes, was found to be unsatisfactory because of the poor frequency response of the amplified signals.
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• 57
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 447-455
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The kinetics of ethylene hydrogenation to ethane are studied in a 7.0 cm diameter fluidized packed-bed reactor. The fixed packing, 1.27 cm nickel on alumina catalyst, is used in conjunction with both -48/+100 mesh alumina and -50/+170 mesh glass inert fluidized particles. Reactant mixture is passed through the reactor at velocities sufficient to fluidize the inerts. Conversions from 0 to 91% are observed over the temperature range 56° to 261°C and flow rate range 10 to 800 cm3/s.The mass transfer coefficient and reaction rate constant are simultaneously evaluated from integral conversion data. The mass transfer coefficient between the interstitially fluidized bed and the catalyst surface is correlated in dimensionless form asNsh = 0.77 NRe0.418 NSc1/3The correlation is significant at the 95% confidence level that is, r = 0.59, p′ 〉 0.Predictions of conversion using both the mass transfer coefficient correlation and a Langmuir-Rideal reaction expression are in good agreement with experimental data. The effects of contact time and catalyst diameter on conversion are also presented. Film diffusion influences become limiting at temperatures above 100°C at the velocities studied. Diffusional resistances were found to be important at Reynolds numbers below 100, at 186°C. No significant difference in reaction rate was found between fluidized alumina and glass inert particles under comparable operating conditions.
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• 58
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 469-478
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Coupled diffusion generated countergradient transport through membranes is analyzed by experimental and theoretical means. Membrane wedge interferometer experiments on an ethanol—water-cellophane membrane system show that net countergradient mass transfer of the less permeable component ethanol may be generated over a wide concentration range. A theoretical analysis of an idealized membrane separating two binary bulk solutions is developed to display further the major features of diffusional coupling effects, and good agreement between observed and predicted countergradient transport characteristics is shown.
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• 59
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 493-502
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Equations describing phase volumes in multicomponent, multiphase systems in the neighborhood of critical points are derived to aid in the location of such critical points. The theory is in good agreement with experiments for three ternary systems and four surfactant systems of the type used for tertiary oil recovery.
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• 60
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 516-521
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The use of helical ribbon agitators to mix viscous non-Newtonian fluids has been investigated. A generalized model, based on an appropriate definition of effective viscosity, is proposed to predict power consumption. This model is most successful with fluids that do not have a high degree of elasticity.It was found that the efficiency of mixing of pseudoplastic fluids was about half of that of Newtonian fluids in the same mixer, while the efficiency of mixing viscoelastic fluids was still lower and approximately independent of the mixer geometry. Blade width was the primary variable affecting the mixing efficiency on inelastic fluids.
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• 61
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 542-544
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 62
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 547-548
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 63
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 552-554
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 64
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 560-560
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 65
Electronic Resource
Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979)
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
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• 66
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 583-591
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: The present research concerns mechanism and rate of reaction between dissolved ozone and phenol in homogeneous solutions. The stopped-flow technique was employed to obtain absorbances during reactions; the kinetic experiments were conducted at temperatures varying from 5° to 35°C in aqueous solutions with pH values ranging from 1.5 to 5.2.The kinetic data indicated that the absorbance of a mixed solution increased rapidly in the very early portion of the reaction and then declined slowly in the remaining period. The rate of reaction in the early period was first order with respect to both phenol and ozone concentrations. The rate constant increased with pH value and temperature, and an activation energy of 5.74 K cal/mole was obtained. Further tests showed that the dissolved ozone was consumed completely in the first period and that in the second period the intermediate products were decomposed without depletion of ozone. Catechol, o-quinone, hydroquinone, oxalic acid, humic acid, and a dimer were identified from mass spectra as products of the ozonization reaction.A free radical mechanism, with initiation of an electrophilic reaction for the formation of catechyl radical, has been proposed to explain the experimental data for phenol-ozone reaction in aqueous solutions. According to the proposed mechanism, the reaction path through the attachment to ortho position is much more favorable compared with that through the paraposition because of geometric advantage, though quinones and hydroxyphenol can be formed through parallel paths. The products of reaction detected in this research, therefore, are accountable by this mechanism. A rate equation derived on the basis of this mechanism also agrees well with that observed from the kinetic experiments.
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• 67
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 600-609
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Mathematical modeling of a periodically cycled plate column has been completed by using a liquid bypass model to describe nonideal liquid draining. A numerical solution over a wide range of parameters provides a closed envelope of feasible solutions. A region of this envelope encloses favorable operating values of the parameters, while the other region is unfavorable. Measurements of the parameters for nonideal liquid draining in a 600 mm diameter column fitted with sieve plates lead to predictions of only small improvements in separation performance. Modifications to the column intervals are required to move the parameters into a more favorable position in the solution envelope.
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• 68
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Hoboken, NJ : Wiley-Blackwell
AIChE Journal 25 (1979), S. 609-615
ISSN: 0001-1541
Keywords: Chemistry ; Chemical Engineering
Source: Wiley InterScience Backfile Collection 1832-2000
Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
Notes: Sparse linear systems in bordered block-triangular form can be efficiently solved by block-triangular splitting, a new technique that provides a drastic reduction in the fill-in (loss of sparsity) that occurs in the direct solution of such systems. This technique is applicable in the iterative solution of the large systems of nonlinear equations that arise in the equation oriented approach to process simulation and design calculations.