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  • 1990-1994  (794)
  • 1920-1924
  • 1993  (794)
  • 1922
  • Engineering  (661)
  • Industrial Chemistry and Chemical Engineering  (133)
  • 1
    Electronic Resource
    Electronic Resource
    Introducing engineering into American secondary education (1993)
    Springer
    Journal of science education and technology 2 (1993), S. 397-406 
    Details
    ISSN: 1573-1839
    Keywords: Engineering ; technological literacy ; hands-on experiments ; active learning ; content instruction ; videotaping
    Source: Springer Online Journal Archives 1860-2000
    Topics: Natural Sciences in General , Technology
    Notes: Abstract Media reports indicate the decline of the technological literacy of American youth, especially that students in other countries are better prepared in science and mathematics. Our active-learning program, which consists of numerous hands-on experiments, introduces engineering applications into science and math programs, that will demonstrate to students the usefulness of the theory that they currently do not see as useful. The program, when fully developed, will make optimum use of technology, especially computers and videotapes. The hands-on experiments allow students to discover fundamental principles through data analysis and then use the principles to synthesize a solution to a technological problem. This discovery-based education will help school systems better meet performance standards such as those in the Maryland School Performance Plan. The experimental approach to science education is especially important in a technology-oriented economy where children use the new technologies without understanding the principles on which they are based.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00694528
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  • 2
    Electronic Resource
    Electronic Resource
    Concurrent boundary element computation (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 83-98 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: A major limitation of the boundary element method (BEM) for the solution of electrical potential problems is the long computational time required. However, a large portion of the calculations involved can be viewed as being parallel in nature and can therefore be computed concurrently. This paper makes an effort to increase the efficiency of the BEM process using transputer-based multiprocessor computing techniques. The algorithms developed may equally well be applied to any multiprocessor system. The application selected to demonstrate the technique is the solution of an electrostatic problem governed by a two-dimensional Laplace equation.A parallel algorithm for problem setup and field extraction using BEM is designed and implemented on a transputer array. Special attention is directed to the utilization of the parallel processors to achieve maximum efficiency. The analysis in this work concentrates on the communication strategies for passing data between processors as well as a consideration of the workload attributed to each processor.The parallel algorithms were implemented using 3L Parallel Fortran; however, the choice of topology for the overall BEM implementation was limited by the fact that certain parts of the algorithm could only utilize a pipeline configuration of processors. Comprehensive results for the parallel BEM algorithm are given and they are encouraging, indicating that parallel processing has much to offer when applied to the boundary element method.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060202
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  • 3
    Electronic Resource
    Electronic Resource
    The efficiency of transmission-line matrix modelling - a rigorous viewpoint (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 109-126 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: The difference equations of the scalar linear transmission-line matrix (TLM) routine as introduced by Johns for numerically solving the diffusion equation are shown to be isomorphic to Goldstein's correlated random walk model of diffusion. For the infinite homogeneous bar their exact solution is derived algebraically and given in the form of Jacobi polynomials. This puts the TLM algorithm on a sounder mathematical and physical basis. The accuracy in solving the diffusion equation is investigated in general form and thus its astonishing efficiency explained. Several other basic questions of this numerical technique are also discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060204
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  • 4
    Electronic Resource
    Electronic Resource
    Electronic band structure for two-dimensional periodic lattice quantum configurations by the finite element method (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 283-297 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: A finite element method formulation is given for solving Schrodinger's wave equation for a single electron in a crystal lattice cell subject to a known periodic potential. The formulation has been implemented for a two-dimensional lattice, with an arbitrary potential profile, modelled by quadratic isoparametric elements, The FEM solver returns a specified number of electronic energy states, En, and nodal values of the complex wavefunctionψn Input data is generated by a standard FEM mesh generator. The postprocessing, given n, for reproducing a full 2-D E-k Brillouin diagram and given k, the electronic distribution, has been implemented. Tests on a 2-D generalized Kronig-Penney energy band model showed excellent agreement; between FEM results and analysis. The solver was further satisfactorily checked against published augmented plane wave calculations for a circular potential well within a square lattice. Specimen results are presented for the same circular well but with graded potential distributions and for a rectangular potential barrier set askew in a square lattice. Two-dimensional energy band solvers have application to superlattice nanostruc- tures, whilst a general, full 3-D FEM quantum solver seems feasible.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060405
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  • 5
    Electronic Resource
    Electronic Resource
    An E-plane sectoral horn fitted with side-lobe suppression devices (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 145-159 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: A finite difference method is used to design a new type of sectoral horn antenna with corner channel inserts which produces a tapered aperture amplitude distribution in the E-plane. The channel inserts, which present a simple modification to the horn aperture geometry, act as effective side-lobe suppression devices. The efficiency of the suppression technique was successfully tested on an experimental horn whose performance is compared to that of a horn with similar geometrical dimensions but with no channel sections.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060207
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  • 6
    Electronic Resource
    Electronic Resource
    Body fitted grid generation with moving boundary and its application for dielectric waveguides (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 127-134 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: The stress birefringence and mode coupling effects in polarization-preserving fibres are most important problems which need to be improved. For a realization of some optical devices, the dielectric waveguide with sinusoidally varying circular cross-section has been investigated. It becomes very important to analyse the electromagnetic field distribution in a dielectric waveguide with a time-dependent moving boundary. This paper shows that numerical methods can simulate the effect of the external disturbance on the dielectric waveguide from time to time. The author has discussed body fitted grid generation with moving boundary for the Poisson and Laplace equations.1,2 We have extended this technique for Maxwell's equation. The technique employs a kind of an expanded numerical grid generation. As the author adds the time component to grid generation, the time dependent co-ordinate system which coincides with a contour of moving boundary can be transformed into a fixed rectangular co-ordinate system. We could show the electric distribution in the waveguide time by time to verify the possibility of an application for an optical fibre. This technique makes it possible not only to analyse the effect of the external disturbance in a coherent optical communication system but also to fabricate optical devices.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060205
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  • 7
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993) 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060301
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  • 8
    Electronic Resource
    Electronic Resource
    Consistent finite difference modelling of Maxwell's equations with lossy symmetrical condensed TLM node (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 207-220 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: A propagator integral interpretation for general TLM processes is presented and applied to discretized Maxwell's equations. The approach provides exact algebraic solutions of finite difference equations along a quite universal scheme.Specifically, Johns's process based on the symmetrical condensed node is reconstructed and generalized as a clear-cut FD algorithm. The fields computed are exact time-domain solutions of the FD equations, provided that total voltages and currents are evaluated and stub quantities are not externally excited. Losses are very naturally incorporated into the TLM algorithm.The structural similarity of the TLM process (properly operated) with the propagator integral appears just as fundamental as general and should have further applications.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060305
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  • 9
    Electronic Resource
    Electronic Resource
    A mathematical model of dehydroisomerization of methylcyclopentane using a bifunctional catalyst blend (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 191-199 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model of dehydroisomerization of methylcyclopentane in presence of bifunctional catalysts under industrial operating conditions is presented. The model consists of six differential equations. The rate constants are expressed as polynomial functions of the catalyst blend, and coefficients of these polynomials were determined from numerous measurements, taken along the axis of a tubular reactor. The resulting polynomial coefficients led to reaction rate constants which yielded results close to the actual process.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160308
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  • 10
    Electronic Resource
    Electronic Resource
    Extraction of zinc by alkyl thiophosphoric acids with emulsion liquid membranes (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 213-217 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Treatment of a given multicomponent cationic mixture was studied applying the emulsion liquid membrane (ELM) separation technique for Zn recovery. Experimental apparatus and conditions are described. Comparative studies using two zinc-selective ion exchangers (thio-DEHPA and dithio-DEHPA) were carried out whereby the composition of the liquid membrane and the operating conditions were investigated for both extractants. A useful method of representing the concentrations of the feed and the receiving aqueous phase is proposed, which allows the occurrence of break-up and/or osmosis to be easily detected.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160311
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  • 11
    Electronic Resource
    Electronic Resource
    Electrical conductivities of pure organic liquids (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 238-242 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This contribution presents a method of evaluating electrical conductivities of pure organic liquids. Emphasis is placed on the methodology of selection, correlation and analysis of experimental data. The proposed method brings order out of conflicting, confusing and chaotic experimental observations. It is also shown that the consistent and evaluated data are generated at a fraction of the cost and time required for producing the original raw experimental data.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160405
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  • 12
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160501
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  • 13
    Electronic Resource
    Electronic Resource
    Transient behaviour of shell and tube heat exchangersPaper presented by W. Roetzel at the “Jahrestreffen der Verfahrensingenieure”, Wein, September 30 to October 2, 1992. (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 296-302 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Based on the dispersion model rather than on the conventional pluf-flow model, a method of predicting the transient behaviour of parallel and counterflow heat exchangers is developed, whereby the effects of shell-side flow maldistribution and the finite heat capacities of both fluids, tube bundle and shell are considered. The final solution has been obtained by numerical inversion of the Laplace transform, to determine the transient responses to arbitrary inlet temperature variations. The experiment was carried out in a one pass tube heat exchanger. The comparison between therotical and experimental results is presented and the feasibility of this method is discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160503
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  • 14
    Electronic Resource
    Electronic Resource
    Wall factor for acceleration and terminal velocity of falling spheres at high reynolds numbers (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 314-317 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The wall factor for spheres in the acceleration and terminal velocity ranges was determined experimentally for very high Reynolds numbers (13 500 〈 Re 〈 70 000). Experiments were performed with 12, 15, 18, 21, 25 and 31.75 mm spheres, falling in water inside cylinders 3.4, 4.9, 7, 10, 14 and 19 cm in diameter. A published empirical equation was found to yield good results for the terminal velocity wall factor in the range of studied Reynolds numbers.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160506
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  • 15
    Electronic Resource
    Electronic Resource
    A study of phase equilibria sensitivity in the 1,1,1-trichloroethane-1,2-dichloroethane separation by distillation (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 338-340 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The sensitivity of the plate number and reflux ratio to the description of vapour-liquid equilibria in the 1,1,1-trichloroethane-1,2-dichloroethane separation was calculated via case studies. Published experimental data are not sufficiently accurate to satisfy an adequate overdesign of the distillation column. On the other hand, the data are suitable for the design of an extractive distillation.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160510
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  • 16
    Electronic Resource
    Electronic Resource
    Pellet heat transfer coefficients in packed beds: Global and local values (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 363-369 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pellet heat transfer coefficients in a packed bed have been obtained, both for specific individual pellets and for the entire bed. They are referred to as local and global values, respectively. It appears that the local values are scattered around the global value. This is due to the heat transfer coefficient of individual pellets being statistically distributed, as a result of the randomnes of the packing. At low Reynolds numbers, both global and local values fall well below Nu = 2, which is the lower limit for a single sphere in absence of convection. In the literature, this behaviour has been attributed i.a. to axial dispersion and fluid maldistribution. However, these phenomena cannot explain why the same behaviour is observed in slurries. The fact that the local values fall below Nu = 2 would suggest that neither of these explanations is valid for packed beds.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160602
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  • 17
    Electronic Resource
    Electronic Resource
    Kinetics of tetrachloroethene photochlorination in a homogeneous system (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 429-432 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The mechanism of free-radical chain reaction of tetrachloroethene photochlorination in a homogeneous liquid system is discussed and three kinetic models based on the reaction mechanism are presented. The parameters of these three models have been evaluated on the basis of experimental data presented in [1].
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160612
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  • 18
    Electronic Resource
    Electronic Resource
    Comparison of single and double inert tracer fluctuation measurements in a continuous stirred tank (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 234-237 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A comparison is made between two different methods using laser induced fluorescence spectroscopy for measuring local concentration fluctuations in the same stirred tank. The first method using a single inert fluorescent tracer yields a segregation index quite different from that determined by the second method, which requires two inert tracers, a fluorescent one and a fluorescence quencher. By recalling the theoretical background, it is demonstrated that the characteristic segregation indices should be equal for the experiments under consideration. According to the discussion, it is likely that the double tracer method gives more reliable results.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160404
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  • 19
    Electronic Resource
    Electronic Resource
    Micromixing effects on a parallel reaction in flow reactors (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 243-251 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Using the micromixing concepts of Danckwerts and Zwietering, the Peclet number Pe has been correlated mathematically to the degree of segregation J for the axial dispersion model. The results were applied to compare the micromixing effects on a model, mixed-order parallel reaction system in continuous flow reactors. Axial dispersion model, and Ng and Rippin's two-environment model were used to find the micromixing effects in tubular and stirred tank reactors, respectively. The performance of these reactors, with varying geometries, has been evaluated in terms of overall conversion, selectivity, and yield under identical operating and reaction conditions. The overall conversion increases in a tubular reactor with the increase in J, irrespective of the kinetic orders. However, in a stirred tank reactor, the conversion is found to be micromixing-sensitive, depending on the order of reaction. For m = 1 and n = 2 (case 1), the conversion is fairly insensitive to micromixing effects while it decreases for m = 0.5 and n = 1 (case 2) with increasing J. For the same extent of micromixing, a tubular reactor gives, in both cases, a higher conversion than a stirred tank reactor. The selectivity, in either case, decreases in both reactors with increasing segregation effects. However, in each case, the selectivity of a tubular reactor was fairly close to that of a stirred tank reactor at the same value of J. As far as the yield is concerned, both reactors achieve nearly the same value, without significant micromixing effects.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160406
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  • 20
    Electronic Resource
    Electronic Resource
    Activity evaluation of a catalytic distillation packing for MTBE productionDedicated to Professor Dr. Horst Langemann on the occasion of his 65th birthday (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 279-289 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The octane enhancer methyl tertiary butyl ether (MTBE) can be produced very efficiently from methanol and isobutene in a reactive distillation column where the heterogeneous catalyst also acts as distillation packing. Some mathematical models have been published for the simulation of such a process but they focus on the physical transport processes between the vapour and liquid phases. However, the aim of this paper is to analyze the importance of the internal and external multicomponent mass and heat transfer phenomena on the catalyst under boiling conditions. Therefore, experiments were carried out in a reactive distillation column at different compositions of feed, column pressures and reflux ratios using a Raschig ring shaped acidic ion exchange resin as the catalyst. The temperature and composition of the liquid phase entering and leaving the catalytic column section were measured. These data were used to evaluate the effectiveness factor of the catalyst with a rigorous macrokinetic model. It is shown that the effectiveness factor varies significantly along the column length. Under certain operating conditions, decomposition of MTBE can occur accompanied by boiling processes inside the catalyst macropores.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160412
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  • 21
    Electronic Resource
    Electronic Resource
    Flow regimes in circulating fluidized beds (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 307-313 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Based on a comprehensive hydrodynamic analysis, a practical definition of the circulating fluidized bed (CFB) regime has been proposed. It was established that two flow regimes are involved in a CFB: fast fluidization and dense phase conveying. By demonstrating the variation of pressure gradient in both the lower and the upper section of the bed versus superficial gas velocity, the criteria for the determination of transition velocities have been obtained. Literature data which over wider operating conditions, particle properties and bed diameters from the basis of the obtained generalized correlations of transition velocities. A quantitative flow diagram is presented.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160505
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  • 22
    Electronic Resource
    Electronic Resource
    Announcements (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 38-38 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100108
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  • 23
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993) 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100101
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  • 24
    Electronic Resource
    Electronic Resource
    Fractal Characterization of Pulverised Materials (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 1-6 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper describes preliminary work carried out on the applicability of fractal geometry in describing the products of comminution events.A nickel sulphide ore was subjected to two comminution events, impact shattering and ball milling. Fractal analysis was performed on samples of the resulting comminution products.Two differing fractal populations resulted, with the impact sample exhibiting particles having higher boundary fractal dimensions than the milled sample. The fractal dimension of the impact fragments increased with decreasing size, whereas the milled particles displayed a more complex distribution.The under-fractal distributions, of the two populations of fragments, generate straight lines when plotted on Gaussian probability paper. This leads to the possibility of being able to predict the distribution of fragments, in fractal terms, of a particular material when subjected to comminution.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100102
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  • 25
    Electronic Resource
    Electronic Resource
    Estimation of the Effective Measuring Volume of Single-Fibre Reflection Probes for solid volume concentration measurements (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 48-55 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The working principle of the single-fibre reflection (SFR) probe is that light emitted by a laser diode is guided into the measuring volume by the same fibre which receives the proportion of light reflected by the particles in the vicinity of the probe tip and transmits it back to a photosensitive element. In contrast to other configurations of fibre optical probes, the SFR probe is characterized by an unambiguous calibration graph over the entire range of solid volume concentration values. SFR probes have been successfully applied to different kinds of multiphase flow systems, e.g. fluidized beds, pneumatic conveying lines, elutriators and thickeners.A particular question for the interpretation of measurements has always been the effective size of the measuring volume, which is mainly determined by the solid volume concentration. In this paper a simplified mathematical model of the signal generation by backscattering of the emitted light at the particle surfaces is given. The theory takes into account the average optical properties of the solids and their particle size distributions.The particle properties are determined on the basis of this model, which finally delivers the shape, size and depth of the effective measuring volume. For particle sizes between 30 and 120 μm the depth of the measuring volume of a 600-μm fibre probe is between 0.2 mm for solid concentrations near the fixed-bed state and approximately 4 mm for solid volume concentrations as low as 0.1 vol.-%.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100204
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  • 26
    Electronic Resource
    Electronic Resource
    Measurement of Size, Number Concentration and Velocity of Aerosol Particles using an optical particle counter (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 56-61 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: An aerosol measurement instrument is presented which allows for the simultaneous measurement of the size distribution, number concentration and velocities of particles. A commercial optical particle counter (OPC) was modified in terms of optics and signal evaluation to provide the required measurement information. The design of this instrument allows the definition of a cubic measuring volume by purely optical means. This is achieved by an aperture/lens system which projects a sharply defined light beam into a stream of aerosol flow. Light scattered from single particles at average angles of 90° is collected by two opposite receiver units, each projecting light on to a separate photomultiplier. The intensity of the scattered light with this instrument is found to be an unambiguous function of the particle size. The total number of particles detected per unit time results in the particle flux. The particle velocity can be calculated, in principle, through the correlation of the signal length and the optical length of the measuring volume, provided that the particles have a straight trajectory through the measuring volume and the measuring volume length in the mean flow direction is well defined. The absence of sharpness in real optical projections effects a border zone of definite length, in which the illumination declines to zero. This leads, together with the low-pass filtering of the particle signals, to an increase in the length of the signal slopes, causing some difficulties in the determination of the signal length. A digital signal evaluation technique was developed that renders possible the clear differentiation between the slope and the kernel region of the signal. The latter represents the motion of particles through the completely illuminated region, which can be a more accurate parameter to define the signal length. In addition to the signal length determination, a cross-correlation technique was tested for its potential to obtain particle velocity. the instrument has two interlaced measuring volumes of nearly the same size, which are shifted for this special application in the main flow direction by 20 μm. The phase difference between the signals from the two photomultipliers, together with the optical distance, yields the particle velocity.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100205
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  • 27
    Electronic Resource
    Electronic Resource
    In-Line Particle Size Determination for Jet Agglomeration Processes (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 74-78 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In jet agglomeration plants, powders are agglomerated to obtain good instant properties. The free-falling initial material is wetted in a spray cone by droplets or in a steam jet by condensation at the particle surface. In a subsequent region of high particle concentration, collision between particles occurs and agglomerates form, if the forces of adhesion are strong enough. A commercial measurement device, working according to the principle of Fraunhofer diffraction, was modified for in-line application. It was used to measure particle size distributions and concentrations of solid particles and droplets in jets. A model is presented to calculate local particle sizes by means of mass balances from integral measurements over large volumes. The results of in-line particle size and agglomerate size analyses show the practical importance of dry agglomeration during transport and lead to a better understanding of the subsequent wet agglomeration process.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100208
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  • 28
    Electronic Resource
    Electronic Resource
    Announcements (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 92-94 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100211
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  • 29
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993) 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100301
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  • 30
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    Particle Dispersion in Highly Swirling, Turbulent FlowsDedicated to Professor Friedrich Löffler on the occasion of his 60th birthday (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 182-190 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Three-dimensional transport processes of monosized droplets in a turbulent swirling shear layer were investigated experimentally and theoretically. A model experiment was designed that represents the spray dispersion produced by airblast atomizers. Based on the experimental results, a stochastic dispersion model was developed in the frame of a Lagrangian formulation. Comparison with these experimental data for the dispersion of monosized droplets were made and proved to be satisfactory. The analysis of the remaining differences between calculation and measurement emphasized the importance of an accurate description of gas-phase turbulence characteristics.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100406
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  • 31
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    Comparison of Dry Test Sieving on Woven Wire Cloths versus electroformed sheetsDedicated to Professor Friedrich Löffler on the occasion of his 60th birthday (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 222-225 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Dry test sieving results given by woven wire cloths with a square mesh and by round electroformed apertures were compared using sands of various origin. The difference has been found to be constant and independent of substance and quantile. The quantile obtained on a square mesh was converted into the corresponding quantile on an electroformed sheet of the same nominal aperture by multiplication by a constant factor of 1.21 ± 0.04.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100410
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  • 32
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    Dense Monolayers of Monodisperse Opaque Spheres: Transmission and diffraction in the fraunhofer domainDedicated to Professor Friedrich Löffler on the occasion of his 60th birthday (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 201-211 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The transmission and diffraction of radiation through dense monolayers of monodisperse opaque spheres were studied for the Fraunhofer domain. Theoretical considerations, numerical calculations and experiments on ultrasonic transmission and on laser light transmission and diffraction yielded corresponding results. Complementary studies included the cases of sterically non-interacting particles (by numerical simulation) and of small particle size parameters (by ultrasonic extinction). Transmission was found to be, in general, a non-linear function of the monolayer density. Secondary effects on the transmission can be attributed to the effect of the monolayer structure (characterized by the pair correlation function) on the angular distribution of diffracted intensity. The results were found to be in accordance with experimental results on extinction in three-dimensional systems.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100408
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  • 33
    Electronic Resource
    Electronic Resource
    Editorial (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 228-228 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100502
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  • 34
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    Fractal Differentiation Between Wear and Contaminant Particles found in mining machinery lubrication systems (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 308-312 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper describes preliminary work carried out on the applicability of fractal geometry for differentiating between wear and contaminant particles found in mining machinery lubrication systems.Coal dust, stone dust and roadstone dust from a granite quarry were used as the contaminant particles and the particles from two crushers, which had failed whilst in service, were used to provide the wear particles.Two differing populations appeared with the wear particles having higher boundary fractals than the contaminant, but tending to spread across a wide range of fractal numbers, whereas the contaminants were lower and fairly tightly grouped.The underfractal distributions of the two populations of particles, generate straight lines when plotted on Gaussian probability paper. This leads to the probability of being able to predict the distribution of particles, in fractal terms between wear and contaminant particles.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100604
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  • 35
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    Measurement of Aggregate Fractal Dimensions Using Static Light Scattering (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 239-245 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Aggregates formed from colloidal particles will vary in shape according to the aggregation regime prevalent. Compact structures are formed when the aggregation is slow, whilst loose tenuous structures are formed when rapid (or diffusion limited) aggregation prevails. These structures can be fractal in nature, that is, there is a relationship between porosity and the number of primary particles making up the aggregate, and is described by the fractal dimension, dF. Fractal dimensions of hematite aggregates have been measured experimentally using the static light scattering technique. Fractal dimensions varied with aggregation regimes; for the rapid aggregation regime, dF was found to be 2.8, whilst for conditions in which aggregation was slow (retardation forces prevail), dF's of 2.3 were measured. For conditions which lead to aggregation in which both diffusion and retardation forces play a part, structures with fractal dimensions such that 2.3 〈 dF 〈 2.8 were found.The effects of adsorbed fulvic acid, a naturally occuring organic acid, on the kinetics of hematite aggregation and on the resulting structure of hematite aggregates were also investigated. The study of aggregate structure shows that the fractal dimensions of hematite aggregates which are partially coated with fulvic acid molecules are higher than those obtained with no adsorbed fulvic acid. The scattering exponents obtained from static light scattering experiments of these aggregates range from 2.83 ± 0.08 to 3.42 ± 0.1. The scattering exponents of greater than 3 indicate that the scattering is the result of objects that contains pores which are bounded by surfaces with a fractal structure, and can be related only to surface fractal dimension. The high fractal dimensions are due to restructuring within the aggregates, which only occured at low coverage by the organic acid.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100505
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  • 36
    Electronic Resource
    Electronic Resource
    Editorial (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 300-300 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100602
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  • 37
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    Determination of the Fractal Dimension of the Irregular, Compressive Stress-Strain Relationships of brittle, crumbly particulates (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 301-307 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The apparent fractal dimension of normalized rugged compressive force-deformation curves of two types of brittle particulates was determined using the blanket algorithm. Although the shape of the original force-deformation relationships of the individual specimens was irreproducible, the apparent fractal dimension of the normalized data was fairly constant and characteristic of the material. The applicability of the algorithm and the validity of the results were tested with computer simulated relationships generated with a set of Weierstrass functions whose fractal dimension was known a-priori. It is demonstrated that as long as the resolution along the two axes is the same, the fractal dimension so calculated provides an absolute rather than a relative measure of the relationship's jaggedness.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100603
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  • 38
    Electronic Resource
    Electronic Resource
    Particle Trajectory Effects in Phase Doppler Systems: Computations and experiments (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 332-338 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of the particle trajectories on phase Doppler measurements were explored numerically using generalized Lorenz-Mie theory. Computations were performed for a commercial phase Doppler system and various schemes for elimination of the trajectory effects were examined. It is shown that these effects cannot be completely suppressed if the ratio of the two measured phase shifts from a single receiving unit is used to validate the measurements. On the other hand, the errors due to particle trajectories can be eliminated satisfactorily by employing an additional receiving unit, which allows one to detect the asymmetry of the scattered light pattern due to displacement of the particle trajectory from the centre of the measuring volume. A preliminary experimental evaluation of this method is presented and discussed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100607
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  • 39
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993) 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060101
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  • 40
    Electronic Resource
    Electronic Resource
    Efficient analytical-numerical modelling of ultra-wideband pulsed plane wave scattering (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 3-17 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Ultra-wideband (UWB) pulsed plane wave scattering from a large but finite strip grating in free space is analysed in the frequency domain via decomposition into plane wave spectra, implemented numerically by the method of moments, and then inverted into the time domain (TD). To make this procedure practical under UWB conditions, closed form expressions are derived for interaction integrals involving widely separated expansion and testing functions. These closed forms are based on a judicious choice of the basis functions, and on asymptotic methods for reducing the integrals. Although large separation distances are assumed, the expressions have been found to be accurate for separations as small as 0·1 wavelengths. The TD self terms can also be evaluated efficiently. To test the frequency domain algorithm, comparisons are made with available data in the literature for surface currents and far-field scattering from multiple strips. New short pulse TD results are shown as well.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060103
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  • 41
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    Spatially weighted numerical models for the two-dimensional wave equation: FD algorithm and synthesis of the equivalent TLM model (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 47-65 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: In this paper a new TLM model for the two-dimensional wave equation is introduced. It is synthesized directly from a FD algorithm. The FD algorithm is second-order-accurate in both space and time, and is explicitly time-stepped. The spatial derivatives in the FD algorithm are approximated by the weighted combination of two standard central difference stencils, one oriented as usual, the other rotated by 45° with its arms extended by a factor of (2)1/2. The TLM model is realized as the weighted connection of two original models (with the same geometrical configuration as the FD algorithm). The weighting in the TLM model is accomplished by using a variable intrinsic impedance for specific elemental transmission lines. The FD and TLM methods possess identical dispersion relations if the former is operated at its upper limit of stability. Therefore, under these conditions both represent identical models for the simulation of wave propagation. The propagation characteristics of the new model are investigated and the conditions for approximate numerical isotropy are provided. The numerical implementation (scattering matrix and transfer event) is described. To validate the new model, the calculation of cutoff frequencies of various modes in rectangular waveguide is performed. Comparison with analytical results (for an unfilled waveguide) and other numerical results (for a waveguide partially filled with a dielectric) validate the implementation of the model.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060106
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  • 42
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    Redundancy and its implications in TLM diffusion models (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 135-144 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Redundancy in the simplest form of a two-dimensional TLM network is identified and a method of eliminating it is described. Results obtained using the non-redundant algorithm are compared with those derived from the standard, redundant algorithm. The non-redundant approach is extended to deal with non-uniform elemental capacitance; a cylindrical geometry is taken as an example of this. The scope for and benefits of rendering TLM diffusion models non-redundant are discussed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060206
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  • 43
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    Thermal radiative boundaries in TLM (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 165-166 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060209
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  • 44
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    Boundary element estimation of current density distribution and eddy current loss in bundled multi-wire cables (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 169-181 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: A numerical approach to the estimation of the current density distribution and the eddy current loss in bundled multi-wire cables using the boundary element method is proposed. Under the assumption of the gradual twist of the bundled wires, the cables are modelled to be two-dimensional with respect to their cross-sections. Three-phase transmission lines of cyclic symmetrical configuration are considered for which a reduction method is utilized to provide efficient computation. Some numerical demonstrations are made for three types of three-phase transmission-line models, consisting of a single wire and three and seven bundled wires. Two cases are considered: one in which the bundled wires are electrically contacted one to another on their surfaces and one in which they are independently insulated. The equivalent resistance is also calculated to examine the skin effect. The skin effect and the effectiveness of the multi-wire configuration to reduce the skin effect are well demonstrated.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060302
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  • 45
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    An investigation of the different TLM configurations used in the modelling of diffusion problems (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 253-268 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: The commonly used transmission-line modelling (TLM) network of one-dimensional diffusion problems often results in unwanted oscillations. Two different TLM configurations (line boundary (LB) and resistance boundary (RB)), are investigated with some techniques necessary to reduce the oscillations. Comparisons between the various LB and RB models addressed in this paper, indicate that, in general, two-dimensional TLM models produce consistently more accurate results.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060403
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  • 46
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    The analytical and numerical solution of electric and magnetic fields, K. J. Binns, P. J. Lawrenson and C. W. Trowbridge, Wiley, New York 1992. Price: US$ 79.95 (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 305-307 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060407
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  • 47
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    Masthead (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160101
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  • 48
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    Increased surface tension of pretreated plastics investigated with a fully automatic device (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 24-25 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Measurements of surface tension of flame-, plasma- and UV-treated PP-EPDM samples show that all three methods of pretreatment significantly increase the surface tension. The flame or plasma pretreatment increases especially the polar element of surface tension while the UV-treatment enhances the disperse element. The measurements were carried out with a new fully automatic unit for determining contact angles (AURAM).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160105
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    Binary ion exchange equilibrium for Ca2+, Mg2+, K+, Na+ and H+ ions on amberlite IR-120 (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 35-39 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experimental data are reported for ion exchange equilibria of binary systems on Amberlite IR-120 resin, at different temperatures and total ionic concentrations in aqueous solutions. These systems exhibit non-ideal behaviour in both phases, and the equilibrium characterization has been based on the law of mass action, using Wilson and Meisssner, and Kusik equations to correlate the activity coefficients in the resin and aqueous solutions, respectively. Equilibrium constants, standard thermodynamic properties (Gibbs free enthalpy changes, enthalpy and entropy) and Wilson binary parameters were obtained as functions of temperature.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160107
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  • 50
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    Masthead (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160201
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  • 51
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    Kinetics and mechanism of oxidative coupling of methane over sodium-manganese oxide catalyst (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 62-67 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The kinetics of methane oxidative coupling (OCM) was studied using 1 g of Na-Mn2O3 catalyst at 1073 to 1123 K, in an integral flow reactor (I.d. = 10 mm), at atmospheric pressure with methane and oxygen partial pressures of 0.27 and 0.13 bar, respectively, so that the ratio of CH4 to O2 was 2. The flow rate range was 50 to 200 ml/min. the kinetic data were analyzed by the Rideal-redox type of rate equation assuming the methyl radical and active surface oxygen to be the steady-state intermediates. Oxidation and reduction rate constants (Kox, Kred) for methane consumption were calculated from experimental catalysis results by computer simulation using the multiple least squares method. The activation energies at rate constants Kox and Kred for this type of catalyst were reported as 43.26 and 62.2 kcal/mol, respectively.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160111
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  • 52
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    Temperature oscillation technique for determination of local convective heat transfer coefficients without fluid temperature measurementPaper presented at the “Jahrestreffen der Verfahrensingenieure”, Cologne, September 25 to 27, 1991. (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 89-93 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A new experimental technique with periodic laser heating is described and applied to the measurement of local heat transfer coefficients at the inner surface of an agitated vessel. Only radiative surface temperature measurements on the outer wall of the vessel are necessary.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160204
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  • 53
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    Techno-Economic investigation of an air humidification-dehumidification desalination process (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 270-274 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This article presents a humidification-dehumidification (H.D.) process suitable for desalination of sea- and brackish water. The work correlates performance characteristics of the combination of different components in such a loop. Water yield, energy requirement and design data are evaluated as functions of different parameters. The investigation covered water to air mass ratios ranging from 60 to 80, concentration ratios between 2 and 5, at a temperature difference of between 10 and 16 °C, along the liquid for dehumidification. The results showed that 76% of energy consumed in the humidifier is recovered by condensation. Increase of the concentration ratio to 5 can reduce the make-up water and rejected brine by about 58% and 24% respectively. Cost calculations show that the H.D. process has significant potential as an alternative for small capacity desalination plants and permits to operate systems as small as 10 m3/day in output.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160410
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  • 54
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    Gas and solids mixing in a commercial FCC regenerator (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 109-113 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Mixing of gas, solids and heat in a commercial FCC regenerator, 5.76 m in diameter, was investigated. This regenerator was operated at a high superficial gas velocity (〉1.2 m/s) and high temperature (650-710°C). It is classified as a highly efficient regenerator. The profiles of coke content in the catalyst, gas composition, temperature and pressure were obtained by sampling and instrumental measurement. It was confirmed that a proposed axial dispersion model could be used for a satisfactory prediction of these experimental profiles. The values of gas and solids dispersion coefficients are also presented.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160207
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  • 55
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    Industrial fires and explosions due to electrostatic ignition (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 325-331 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Static electricity is a frequent source of fires and explosions in industry. A variety of operations may generate static electricity leading to such fires and explosions. This requires adequate preventive and protective measures against this hazard. The present paper describes the theory and mechanism of electrostatic sparking, parameters needed to assess the respective hazard in a plant, safety measures to combat electrostatic problems, common operations where such problems exist and measures to eliminate or mitigate these problems.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160508
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  • 56
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    Determination of operating characteristics of agitators in tubes (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 172-179 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Operating characteristics of an agitator in a tube are necessary for the calculation of its pumping capacity and power consumption in a given configuration. General dimensionless equations for pumping and power characteristics are presented which were derived by inspection analysis of basic equations. Experimental procedure for the determination of these characteristics is put forward. This procedure is based on the measurement of flow rate or pressure rise and power consumption for an agitator in a draft tube, calandria or closed tube. The measurements and their evaluation are illustrated on the example of a three-blade screw agitator.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160305
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  • 57
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    Standardization of a newly designed vibrating capillary apparatus for the preparation of microcapsules (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 395-398 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Vibrating capillary apparatus (VCA) was designed and constructed for the preparation of sulphamethoxazole (SMZ) microcapsules using gelatin as a coating polymer. The microcapsules were characterized by physico-chemical methods. The apparent diffusion coefficient Da and diffusion rate constant KBL of the drug were measured at pH of 1.2 and 7.2. Better controlled release products were obtained in the VCA.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160607
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  • 58
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    Conversion of ethanol over metal-exchanged zeolites (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 332-337 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of metal exchange between zeolites and alkali metals (Li, Na, K; zeolite Y, ZSM-5, T), alkaline earths (Mg, Ca, Sr, Ba; ZSM-5), transition metals (La, Ce, Cr, Mn, Fe, Co, Ni, Pd, Cu, Zn; ZSM-5) and aluminium (ZSM-5) on the conversion of ethanol were studied. Activities of the catalysts and selectivities for ethene, C3+ olefins, paraffins and arenes strongly depended on the cation, chosen for the modification. Only ethene was formed by alkali exchanged zeolites, the most active being Li-Y. This could be confirmed by a long-term ageing test with Li-Y pellets under semi-industrial conditions. The exchange of ZSM-5 with alkaline earths or transition metals permitted the formation of a wide variety of products, raning from high ethene to high aromatic yields. A correlation between certain product selectivities and electronegativity was only possible in a rough approximation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160509
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  • 59
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    Masthead (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160601
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  • 60
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    Investigations on hydrodynamics of radial flow moving bed reactorsThis paper was presented at ACHEMASIA'92, International Meeting on Chemical Engineering and Biotechnology, Beijing, PR China, May 1992. (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 383-388 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Distributions of pressure and velocity in the main channels were studied in a radial flow cold model of a moving bed reactor, 500 mm in diameter, in four different gas flow modes, inward Z gas flow, inward Π gas flow, outward Z gas flow, outward Π gas flow. It has been found that, in outward Π gas flow mode, the axial non-uniformity of the gas is at a minimum. The following correlations are proposed for the momentum recovery factors Ka and Kb: Ka = 0.684 + 0.0128 (du/dx)/u, Kb = 1.135 + 0.0158 (du/dx)/u. Pressure distributions in the main channels can be accurately predicted using Ka and Kb.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160605
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  • 61
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    Comparison of selected methods for downstream processing in the production of bacterial lipase (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 405-412 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Enzymes are of growing interest to the chemical and pharmaceutical industries as highly specific biocatalysts. An obstacle to a large-scale application of such proteins is the expenditure on recovery operations which can amount up to 80% of the total production costs. Therefore, it is necessary to investigate in detail the individual stages of downstream processing in order to obtain high product yields without loss of quality. After a survey of recovery operations and information on some special features of proteins which are relevant to downstream processing, this paper deals with the methods of precipitation, chromatography and foam fractionation. Several results obtained with a real, multicomponent system, namely the supernatant of lipase fermentation, are presented and compared with one another.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160609
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  • 62
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    Comparison of cracking and hydrocraking of n-heptane on H-ZSM-5 catalystsDedicated to Professor Emeritus Dr. Hanns Hofmann on the occasion of his 70th birthday (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 422-428 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Acid catalyzed cracking and bifunctional cracking of n-heptane were investigated on HZSM-5 catalysts. At a reaction temperature of 543 K, the cracking on metal-free zeolite was found to be directly proportional to hydrogen partial pressure. Hydrogen influences the hydrogenation of product olefins and carbon deposits and therefore enhances the overall activity. Under the same conditions, in the presence of platinum, the hydrocracking rate reaches a maximum with increasing hydrogen partial pressure. The reaction can be formally described by a Langmuir Hinshewood mechanism: hydrogen is adsorbed on Pt in competition with hydrocarbons. The maximum reaction rate depends on a favourable ratio of the two adsorbed reactants. The energy of activation of hydrocracking was over 100 kJ/mol higher than that of acid cracking.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270160611
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    Optimization and adaptive control of a semi-batch synthesis reactorPaper presented by J. Uhlemann at the “Jahrestreffen der Verfahrens-Ingenieure”, Köln, September 25 to 27, 1991. (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 17-23 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The optimization of a chemical synthesis aims at an adjustment of the operating conditions, i.e. pH, temperature and initial concentrations, in order to obtain maximum yield, minimum operating costs or similar. The optimization effort may be considerable so that, in many cases, its cost cannot be justified, especially for small volume products. This paper introduces a new strategy, namely to establish the optimum operating conditions with a relatively small effort. The new approach is illustrated by the synthesis of 2-furyl oxirane. In the first step, a simplified mechanistic process model has to be determined on the basis of easily accessible experimental data. Initial and final concentrations of all reacting components, reaction time and temperature must be known. A two-step evaluation yields the stoichiometric coefficients of all the occurring reactions as well as the parameters of the Arrhenius model. This so-called trend model is used in the optimization of the operating conditions. It is not only important to know the optimum operating conditions but also to maintain them as close as possible in practical operation. An adaptive controller is well suited to such an application and its use is discussed.
    Additional Material: 9 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270160104
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  • 64
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    Mass transfer in packed columns: The cylinder model (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 46-57 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In order to predict mass transfer in packed columns, it is necessary to know the interfacial area. The well-known and often cited equation (Onda, Kolev, Zech, etc.) do not yield precise values for the mass transfer coefficient βL ae or the interfacial area ae, especially for modern packing elements. A new model will be presented which takes into account the structure of packing (cylinder model) as well as the structure of the liquid hold-up. This model allows the separation of liquid flow through packings into its main constituents, i.e. rivulets and drops (freely falling). The determination of the structure of liquid flow allows the prediction of effective interfacial areas as well as of volumetric mass transfer coefficients for irrigated large packing elements manufactured from plastics, metals or ceramic. The applicability to novel future packings is one of the advantages of the new model.
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160109
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  • 65
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    Liquid phase oxidation of α-pinene initiated by ozone. 1. Conversion of α-pinene and formation of its hydroperoxide (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 68-74 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The use of ozone as initiating agent in the liquid phase oxidation of α-pinene has been investigated. The first intermediate product of the reaction is the hydroperoxide of α-pinene. Both, ozone partial pressure and its initiation time exert an inhibiting effect on the conversion of α-pinene but yield higher selectivities for the hydroperoxide of α-pinene compared with those of oxidation without ozone. In all cases, temperature was found to be the most important variable affecting the oxidation rate. From a mechanism of radical reactions, kinetic equations, consistent with the experimental results, corresponding to α-pinene oxidation rate and net formation rate of its hydroperoxide, were obtained. The rate constants are given as functions of temperature. The results also suggest that a fraction of the hydroperoxy radicals decomposes to yield other products such as verbenol and verbenone, identified in this work, and whose kinetics will be reported in a later paper.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270160112
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    A general method of designing gas and gas-liquid injectors using laws of turbulent jet mixingPaper presented at the “Jahrestreffen der Verfahrens-Ingenieure”, Cologne, 25-27 Sept. 1991. (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 94-101 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Based on the equation for entrainment of a turbulent free jet, a simple method of designing gas and gas-liquid injectors is presented. Using the formula for mass flow ratio of an injector consisting of a nozzle and a short cylindrical mixing tube open at both ends, a general equation for designing any injector with variable geometry and flow resistances is given. The optimization procedure is outlined. Compared to the conventional design of injectors, starting from macroscopic mass and momentum balances, the present method is much simpler, easily applicable and involves only one empirical entrainment coefficient. It is particularly advantageous in the case of variable density of the motive and entrained fluids since the density ratio appears explicitly in the relevant equations.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160205
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    Bed collapse technique for estimating parameters of generalized wake model for a three-phase fluidized bed (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 119-124 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The hydrodynamic behaviour of a cocurrent gas-liquid-solid fluidized bed was studied by using the bed collapse technique. The key parameters, k and x, of the generalized wake model were estimated. Compared with other existing methods for evaluating the parameters k and x, the bed collapse technique shows some distinct advantages. Parameters are derived directly from experiments in a three-dimensional three-phase fluidized bed and there is no need to assume that a bubble and its wake form a perfect sphere. Hold-up data of the three-phase fluidized bed predicted by the generalized wake model with k and x estimated by the bed collapse technique are in good agreement with those obtained via the traditional pressure-drop method.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270160209
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  • 68
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    Influence of solids concentration and static mixers on fluid dynamics in three-phase fluidized bed bioreactors (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 147-152 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The influence of solids concentration and static mixers on the hydrodynamics of the gas phase was studied for a three-phase fluidized bed bioreactor (air, nutrient solution, biocatalyst Ca alginate beads). Axial gas hold-up profiles, radial gas velocity profiles, mean bubble diameter and gas/liquid interfacial area per unit volume were measured in a bubble column (DR = 0.142 m, HR = 1.748 m). The influence of solids concentration on the gas hold-up is insignificant; static mixers enhance the gas hold-up in the reactor volume element in which they are installed. Axial gas velocity decreases with increasing solids concentration. At high solids concentrations, static mixers exert little influence on the gas phase but, at low concentrations, they do. A model is suggested to describe the influence of solids concentration (characterized by turbulent viscosity vt) and static mixers (characterized by profile parameter n) on the gas velocity profile.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270160302
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    Kinetics of coal desulphurization by Acidianus brierleyi (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 180-185 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Acidianus brierleyi was demonstrated to remove pyritic sulphur from coal. A. brierleyi was also found capable of catalyzing the removal of what is normally reported as organic sulphur from coal 171US34. A kinetic analysis was performed by assuming a first order reaction. The first order kinetics allowed a comparison with literature data for Thiobacillus ferrooxidans. Also, formation of jarosite was taken into account in the analysis. The simple first order kinetics was observed to fit the data on removal of sulphur satisfactorily.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/ceat.270160306
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  • 70
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    Masthead (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993) 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160401
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  • 71
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    Liquid homogenization in agitated tanks (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 229-233 
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    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This paper presents a very simple model of liquid homogenization in a mixing tank. The model, based on the pumping capacity of impellers and the degree of homogeneity, is valid for turbulent mixing; however, it has been extended to transient regime of mixing (Re = 100 to 1000).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160403
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    Measurement of gas hold-up in three-phase systems by ultrasonic technique (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 260-262 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: It was established by using double impulse method that the transmission time of an ultrasonic wave, which passes near a bubble, is either shorter or longer than that in the liquid system. This is attributed to the fluid vortex originated by the bubble rising ahead of the wave. The longitudinal distribution of gas hold-up in a three-phase system, measured by analyzing wave shape and reduction of transmission time is in good agreement with that obtained by using the static pressure method. This indicates the possibility of application of ultrasonic techniques to the simultaneous measurement of phase hold-ups in the three-phase system.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160408
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  • 73
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    Drying characteristics of starch in an inert medium fluidized bed (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 263-269 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of gas velocity (0.32 to 0.67 m/s), inlet gas temperature (25 to 100 °C) and the mass ratio of starch to inert particles (0.1 to 0.4) on the drying rate of starch in a 0.083 m-ID × 0.80 m-high inert medium fluidized bed were investigated. The drying mechanism in an inert medium fluidized bed can be classified into adhesion-dispersion, evaporation and disintegration steps. The drying rate increases with the increasing inlet gas temperature and velocity; the rates being about 10 times those reported for an agitated pan dryer. However, the drying rate decreases slightly as the mass ratio of starch to inert particles increases. Also, the drying rate exhibits a maximum at an optimum bed porosity. The drying rate data obtained in an inert medium fluidized bed have been correlated with the relevant dimensionless groups, i.e. Stefan and particle Reynolds numbers based on the theory of isotropic turbulence.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160409
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  • 74
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    Cooling water treatment by ozonization (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 275-278 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Ozonization of water in a cooling tower was investigated. A laboratory experimental set-up was employed to study changes in water quality during ozonization. Measured data were analyzed in the context of cooling water's resistance to corrosion, scaling and biofouling. A method is proposed for determining the suitable dosage of ozone for maintaining the necessary water quality. It has been found that ozonization is very effective in maintaining the correct water quality for the required purpose and provides an attractive alternative to the conventional multiple chemical method of cooling water treatment.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160411
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  • 75
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    Fuzzy sets. Introduction to theory and applications in process engineering (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 291-295 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Fuzziness is quite a different notion from probability. Probability describes the objective uncertainty obtained on the basis of a large number of observations. Fuzziness describes the uncertainity that has a subjective meaning. Fuzzy notions describe the degrees of possession of a given property. The popularity of fuzzy set theory in solving control problems results from its ability to treat some situations which are difficult to deal with by the classical control theory. Fuzzy sets are used to control ill-defined, complex, non-linear systems. There are two aspects of this phenomenon. The first aspect concerns the descriptive ability of fuzzy sets. The second important feature is the applicability of fuzzy sets to work with incomplete, contradictory and subjective information. Fuzzy set theory is becoming increasingly important tool in the new fast developing disciplines of artificial intelligence: expert systems and neural networks. It creates completely new opportunities for the application of fuzzy sets in chemical engineering.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160502
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  • 76
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    Studies on parametric sensitivity and safe operation criteria of batch processes (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 318-324 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Heat accumulation in batch reactors may eventually lead to a temperature runaway. Critical values of process parameters were used to investigate process safety. Parameter sensitivity is discussed for a wide range of operating conditions. Two criteria for safe operation are presented, based on critical values of process parameters.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160507
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  • 77
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    Defect structure of metal oxides at high temperatures (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 341-346 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: High temperature oxidation of some metals contained in special alloys has been studied. Defect models for pure an doped CoO and pure NiO were developed and fitted to electrical conductivity data. The models involve different kinds of theoretically possible complex defects with different numbers of vacancies and interstitials forming a cluster. Equilibrium constants for defects formation have been estimated using an algorithm based on the constrained variation method that allows fitting of data to implicit models involving errors in all the measured variables. Results indicate the presence of a significant concentration of complex defects in CoO at high temperatures, while confirming the rather small concentration of these defects in NiO.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160511
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  • 78
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    A physical model for the prediction of liquid hold-up in two-phase countercurrent columns (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 370-375 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This contribution presents the determination of liquid hold-up in gas/liquid two-phase countercurrent columns filled with random or structured packings. The equations resulting from the established physical relationships are varified against the values for liquid hold-up determined experimentally on 56 different column packings and 16 gas/liquid systems. The experimental and calculated results agree well, with only slight deviations. This also applies to the range between the loading and flooding points for two-phase countercurrent flow.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160603
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  • 79
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    Correlation and prediction of gas solubility in heavy complex liquids (1993)
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 16 (1993), S. 399-404 
    Details
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A lattice-gas model is used for calculating the solubilities of light gases in heavy complex hydrocarbons. For waxes, the model gives a good prediction of the solubilities on using the molecular weight of the liquid to describe the solvent. For crude oils and coal-derived liquids, the prediction is of only modest quality. However, it does improve on using experimental Henry's constants.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ceat.270160608
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  • 80
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    The Angular Polarization Ratio for the Characterization of Small Droplets in Oil Sprays (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 19-25 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The angular patterns of the polarization ratio were calculated for droplets with diameters between 0.020 and 50 μm at 500 nm wavelength. It was observed that the patterns for droplets slightly smaller than 1 μm were dominated by a backward peak belonging to the glory. The peak was successfully used to characterize aerosols of light and heavy oils with a Junge-like size distribution. Experiments conducted with heavy oil sprays produced by air-assisted atomization presented the same feature. A quantitative comparison of the experimental results with the Lorenz-Mie theory showed that the size distribution of these sprays was bimodal.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100105
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  • 81
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    Masthead (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993) 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100201
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  • 82
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    Scattered Light Photometer for On-Line monitoring of size distribution parameters and particle number concentration (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 33-37 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A scattered light photometer which monitors the particle number concentration of aerosols is described. The photometer measures the scattered light from illuminated submicron particle clouds with known material properties at certain scattering angles. Intensity ratios in combination with the degree of polarization are used to determine the mean particle diameter and the geometric standard deviation of an assumed log-normal particle size distribution. The determination of the particle size distribution is based on an algorithm which compares the measured and calculated (Mie theory) relative intensity quantities described. Furthermore, the particle number concentration is monitored from a single absolute intensity measurement at one scattering angle. In order to obtain quantitative results a spherical particle shape is required.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100107
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  • 83
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    Particle Dynamics in an Electrohydrodynamic Flow Field investigated with a two-component laser-doppler velocimeter (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 41-47 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A laser-Doppler instrument has been used to measure the migration velocity of NaCl particles in an electrohydrodynamic flow field of an electrical precipitator. The measured average migration velocity of 1.40-μm particles (number distribution median with a geometric standard devitation of 1.46) is approximately five to six times higher than the calculated steady-state velocity for a 1.40-μm particle, provided there is a saturation charge of at least 90f%. Further, the particle velocities in the main flow direction are also influenced by the electrical operation conditions. Both observations demonstrate the important role of the state of the electrohydrodynamic flow field (superposition of moving gas ions and neutral gas molecules) on the particle transport, characterized by the dimensionless electrohydrodynamic number NEHD. A comparison between six different electrohydrodynamic states revealed that NEHD ≍ 1 is a critical value for the mutual interactions between the gas ions and the neutral gas phase. Whereas for NEHD values 〉 1 the stochastic particle motion is chiefly determined by the nonsteady-state character of the negative corona, for NEHD values 〈 1 the particle velocity fluctuations are governed by the turbulence level of the neutral fluid. These finding might be helpful in adjusting the operating conditions in electrical precipitators for and optimized particle separation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100203
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  • 84
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    Sampling of Autocorrelating Powder Flows (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 70-73 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Sampling powder flows in industrial grinding circuits are discussed. Work was done with different types of sampler and with different minerals and sampling objectives. It was found that all the samplers showed marked autocorrelation in sample mass for all the minerals ground. Typical autocorrelation could be found at both high (1 · 10-3-15 · 10-3 Hz) and low (1 · 10-4 - 4 · 10-4 Hz) frequencies. Higher frequencies were attributed to powder transport and low frequencies to mill circuit variations. The effects of the found autocorrelation on systematic errors and on industrial sampling schemes are discussed. Systematic sampling produced large errors if operated at sampling intervals that were high-frequency autocorrelation frequencies or small multiples of these. Low-frequency autocorrelation was less detrimental to the sampling results.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100207
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  • 85
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    The Relevance of Particle Measurement Technology to Process Engineering (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 86-91 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: To produce disperse products, the characterization of the disperse state and a knowledge of the property function are essential. Property functions are applied not only to characterize the quality of an end product, but also to determine the influence of different processing steps on its state. Hence it is necessary to know the property and process functions for quality assurance of the products and for safety of the processes.Good laboratory particle measuring technologies are available for investigating property and process functions. On the basis of these functions, process control takes place. On-line or, better, in-line measuring techniques are necessary to enable the accompanying process information to be obtained.
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100210
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  • 86
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    Flow Characteristics of Granular Bulk Materials (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 79-85 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The paper discusses the interest in conventional triaxial tests widely used in soil mechanics for a better understanding of both the mechanical behaviour and flow characteristics of granular bulk materials. It proposes a rheological characterization of granular foodstuffs on diverse types of stress path using a conventional triaxial cell. The characteristic state concept, defining the disaggregation threshold of the granular structure, is found to be suitable and even indispensible for examining the mechanical behaviour and the flowability of stored bulk materials. The experimental results readily suggest, as an indicator of the arching effect, a rheological index that characterizes the particle interlocking breakdown and hence the flowability of the stored materials. In addition, this study offers a realistic physical meaning for parameters in use in constitutive models (yield conditions and flow rules) when describing granular flow in various hopper geometries. The case of silos equipped with vibrating hoppers necessitates additionally the study of the rheological behaviour of materials under cyclic and vibratory loadings in order to analyse the processes of densification or disaggregation conditioning the flowability of the stored materials during emptying operations.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100209
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  • 87
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    Light Scattering by Anthophyllite-Crocidolite Asbestos Fibers. Part I: The domain of convergence of the EBCM theory (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 111-117 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The Extended Boundary Condition Method (EBCM), also known as the T-matrix method, is used to compute exactly the scattered intensities from homogeneous isotropic circular cylinders characterized by relative refractive index N, diameter D and length L. The domain of convergence of the method regarding the parameters N, D, L is established. The effect of the geometry of the fiber ends on the scattered intensities is considered. The incident field is assumed to be a linearly polarized plane harmonic wave.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100303
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  • 88
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    The Characterisation of Particles Using the Settling Rate dependent movement in two phase flowsRevised version of a paper presented at the 25th Anniversary Conference “Particle Size Analysis”, Loughborough, University of Technology, 17th-19th September 1991.Dedicated to Professor Friedrich Löffler on the occasion of his 60th birthday (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 159-166 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The drawback of conventional sedimentation methods, mainly their extremely long sedimentation time for small particles, can be overcome in two phase flow systems. In this paper several principles which permit the rapid determination of settling rate distributions are discussed. Settling rate distributions can be determined from the accelerated particle movement in a flow of constant velocity at low and high solids concentrations. Another system uses accelerated flow at low solids concentrations. The best utilisation of settling rate applications have socalled cross flow systems as set up in a stagnation point flow, in a flow round a bend, or in the decelerated particle movement perpendicular to a flow of constant velocity.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100403
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  • 89
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    Cessation of Aggregate Growth (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 152-155 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Various methods are available for reducing or ceasing growth of aggregating suspensions including the addition of highly charged adsorbents (such as gelatin), reduction of ionic strength by dilution, increase in surface charge by alteration in pH and reduction in suspension temperature. The effectiveness of each of these methods in stopping the aggregation of colloidalhematite without altering the aggregate size distribution is examined in this study. Reduction in aggregate temperature is found to be a particularly effective way of stopping the aggregation of hematite while preserving size distribution information.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100308
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  • 90
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    Masthead (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993) 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100401
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  • 91
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    Description of Two-dimensional Distributions of Particle Size and Particle Velocity of a flowing discontinuous phase by means of special mathematical functionsDedicated to Professor Friedrich Löffler on the occasion of his 60th birthday (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 167-172 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: As potential approximation functions for measured two-dimensional distributions, the two-dimensional normal distribution and the two-dimensional log-normal distribution are presented, in addition to mixed forms in which one of the two variables is linearly and the other logarithmically normally distributed. For all four distribution functions, regression curves are calculated, with x being understood as independent and y as dependent variable. The general concept is applied to the specific case of a two-dimensional distribution of particle size x and particle velocity y. In this context, a number of particularities result from the fact that a distinction has to be made between concentration-dependent and flux-dependent measurement.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100404
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  • 92
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    Particle Mass Loading Effect on a Two-Phase Turbulent Downward Jet FlowDedicated to Professor Friedrich Löffler on the occasion of his 60th birthday (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 173-181 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The particle mass loading effect on the flow structure of a two-phase turbulent jet flow was studied. A particle mass loading ratio ranging from 0 to 3.6 was used as the control parameter. The polystyrene solid particles used had nominal diameters of 210 and 780 μm. The flow Reynolds number, which was based on the pipe nozzle diameter and the fluid-phase centerline mean velocity, was 2 × 104 in the current test. A two-color laser Doppler anemometer (LDA), combined with the amplitude discrimination method and the velocity filter method, was employed to measure the mean velocity distributions for the particle and fluid phases, and the turbulent intensities and Reynolds stresses of the flow. The two-phase jet flow field was measured from the initial pipe exit to 90 D downstream. Another one-component He—Ne laser LDA system was also applied to obtain the energy spectra and temporal correlations of the two-phase jet flow.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100405
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  • 93
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    Neural Networks for Flow Regime Identification with dry particulate flow (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 234-238 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: This work on imaging of particulate processes using electrical charge tomography uses two basic techniques: the multi-sensing of electrical charge in a cross-section of the flow pipe and a neural network based flow regime identification system to aid in the image reconstruction process.A measurement system, consisting of sixteen sensors, placed at equal distance from each other around the boundary of a circular 100 mm bore pipe, is used to determine the voltage profile of the flow for several artificially produced flow regimes: full, annular, core, half and stratified. A sand flow system is used to produce these different flow regimes, which are created artificially by using baffles of different shapes that obstruct the sand flow.The voltage profile from the sixteen sensors gives spatial information of the flow regime. These profiles are normalised and formed into patterns that are presented to a Kohonen neural network for classification. Two regime classification between clearly distinct regimes gives an accuracy of identification of 85%. Classification of closely similar patterns show much less accuracy of 30%.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100504
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  • 94
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    In-Process Particle Size Distribution Measurements and Control (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 262-265 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In-process measurement of particle size and concentration distributions provides continuous analysis and quality control of a product stream. Elimination of sample handling and operator manipulation is now possible for most pneumatic flows using optical methods which are properly interfaced with the process stream.The EPCS (Ensemble Particle Concentration & Size) described in the following has been used to obtain detailed size distribution measurements in powder production facilities at two second intervals, and has been successfully used for automatic feedback control.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100508
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  • 95
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    Non-Invasive Size-Control of Pneumatically Conveyed Particles (1993)
    Weinheim : Wiley-Blackwell
    Particle and Particle Systems Characterization 10 (1993), S. 353-356 
    Details
    ISSN: 0934-0866
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Investigations on the size control of pneumatically conveyed coarse particles were carried out using a microphone which detects the structure-borne sound caused by the impact of the particles on the pipe wall. Modes of eigenvibrations of the pipes are excited up to a maximum frequency, which decreases with increasing particle size. In an assembly of different sized particles, the lower frequencies are more stimulated as the fraction of larger particles increases. Changes in the particle size distribution are detected by analysing the intensities of the vibration modes which are set up in the walls of the tube by particle impact. One application is the monitoring of the upper range of a particle size distribution.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ppsc.19930100610
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  • 96
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    Electronic Resource
    The hilbert space formulation of the TLM method (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 29-45 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: The Hilbert space representation of the TLM method for time-domain computation of electromagnetic fields and the algebraic computation of the discrete Green's function are investigated. The complete field state is represented by a Hilbert space vector. The space and time evolution of the field state vector is governed by operator equations in Hilbert space. The discrete Green's functions may be represented by a Neumann series in space- and time-shift operators. The Hilbert space representation allows the description of the geometric structures by projection operators, too. The system of difference equations governing the time evolution of the electromagnetic field in configuration space is derived from the operator equation for the field state vector in the Hilbert space.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060105
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  • 97
    Electronic Resource
    Electronic Resource
    Multiport approach for the analysis of microwave non-linear networks (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 67-81 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: The state and output equations of the overall networks are derived from the state and output equations of individual multiports and knowledge of the interconnections between them. A generalized lumped-distributed L/D multiport is described by its associated state, output and non-linear equations in the time domain. Any network can be considered as composed of a set of multiports and independent sources. These equations have been incorporated into a computer-aided procedure for the analysis of L/D networks. The procedure can be used for the simulation of any non-linear microwave circuit and offers the facility of developing a multiport equivalent circuit for any linear or non-linear device or subcircuit. Several examples are successfully analysed using the developed general program.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060107
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  • 98
    Electronic Resource
    Electronic Resource
    A comparative study of two TLM networks for the modelling of diffusion processes (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 161-164 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: A comparative study of two alternative networks for TLM modelling of diffusion processes has been undertaken. Some of their inherent advantages and disadvantages are analysed according to the ratio between the impedance of the lossless transmission lines and the lumped resistance. Their relative accuracy and utility in controlling the timestep automatically are examined.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060208
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  • 99
    Electronic Resource
    Electronic Resource
    Computer methods in structural analysis, J. L. Meek, E. & F. N. Spon, 1991. 503 pages. Price £25.00, ISBN: 0-419-15440-X (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 167-167 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060210
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  • 100
    Electronic Resource
    Electronic Resource
    Circuit model for a symmetrical condensed TLM node (1993)
    Chichester [u.a.] : Wiley-Blackwell
    International Journal of Numerical Modelling: Electronic Networks, Devices and Fields 6 (1993), S. 183-193 
    Details
    ISSN: 0894-3370
    Keywords: Engineering ; Electrical and Electronics Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: An equivalent circuit for a symmetrical condensed TLM node is presented. The basic circuit has twelve ports and consists of 24 1:1 ideal transformers. Three additional conductances model the conductivity of the medium. The circuit is extended with additional ideal transformers giving six ports for short-circuit and open-circuit stubs which model the permittivity and permeability of the inhomogeneous medium. The scattering matrix of the 18-port network is determined symbolically by solving a set of linear circuit equations. The matrix agrees with previously published results for a symmetrical condensed TLM node, obtained from Maxwell's equations.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jnm.1660060303
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