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  • 1
    Electronic Resource
    Electronic Resource
    A modification to the linpack downdating algorithm (1990)
    Springer
    BIT 30 (1990), S. 707-722 
    Details
    ISSN: 1572-9125
    Keywords: 65F30 ; 65G05 ; 15A23 ; G.4 ; G.1.3 ; Downdating Cholesky Factorization ; LINPACK ; Rounding Error
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Alinpack downdating algorithm is being modified by interleaving its two different phases, the forward solving a triangular system and the backward sweep of Givens rotations, to yield a new forward method for finding the Cholesky decomposition ofR T R −zz T . By showing that the new algorithm saves forty percent purely redundant operations of the original, better stability properties are expected. In addition, various other downdating algorithms are rederived and analyzed under a uniform framework.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01933218
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  • 2
    Electronic Resource
    Electronic Resource
    Gas separation by high-flux, asymmetric hollow-fiber membrane (1986)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 32 (1986), S. 2020-2027 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A mathematical model of multicomponent permeation systems with high-flux, asymmetric hollow-fiber membranes is presented. The model takes into account the permeate pressure variation inside the fiber. In the special case of negligible permeate pressure drop, the model yields a simple analytical solution for membrane area calculation that eliminates the numerical integration step required in existing methods. Laboratory multicomponent permeation experiments have verified the mathematical model and have demonstrated the technical feasibility of using the high-flux asymmetric cellulose acetate hollow fiber for H2, CO2, and H2S separation. It is shown that the selectivity of the cellulose acetate membrane is ideally suited to the recovery of hydrogen from the purge gas of reactor recycle loops. For the separation of high-concentration CO2 or H2S, the test data show that the permeabilities of the individual components in mixed gas permeation are significantly different from those of pure gases.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690321212
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  • 3
    Electronic Resource
    Electronic Resource
    Gas separation by permeators with high-flux asymmetric membranes (1983)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 29 (1983), S. 545-552 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The permeation behavior of the high-flux asymmetric membrane differs from that of the conventional symmetric membrane. A calculation method for predicting the gas separation performance of a permeator with asymmetric membrane is presented. The model takes into account the permeate pressure drop and is applicable to both hollow-fiber and spiral-wound modules. The effect of permeate-feed flow pattern on module performance is analyzed. It is shown that for the high-flux asymmetric membrane, the countercurrent flow pattern is not necessarily always the preferred operating mode. The mathematical model is verified by large-scale field pilot-plant experiments for helium recovery from natural gas using large hollow-fiber modules (220 m2/unit).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690290405
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  • 4
    Electronic Resource
    Electronic Resource
    One-stage method of preparing core-shell particles (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 55 (1995), S. 667-674 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A one-stage method of preparing code-shell particles was developed for the system containing silicone oils and glycidle methacrylate (GMA). Although the formation of core-shell particles for the systems containing silicone oils and methyl methacrylate (MMA) or styrene (ST) is possible in view of thermodynamics, the core-shell particles were not obtained. Factors such as better compatibility of silicone oils with vinyl monomers, higher swelling degree of silicone rubber in the vinyl monomers, and larger addition rate of thevinyl monomers with Si - H during the crosslinking of silicone oil containing vinyl group and Si - H (SVB and SHB) do not favor the formation of core-shell particles. X-ray photoelectron spectrometer (ESCA) was used in determining the formation of core-shell particles. The mechanism of the formation of core-shell particles is discussed. © 1995 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1995.070550502
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  • 5
    Electronic Resource
    Electronic Resource
    Failure of the dilution approximation in block copolymer solutions (1995)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Physics 33 (1995), S. 2289-2293 
    Details
    ISSN: 0887-6266
    Keywords: block copolymer ; order-disorder transition ; neutral solvent ; dilution approximation ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/polb.1995.090331614
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  • 6
    Electronic Resource
    Electronic Resource
    Permeation of water vapor through cellulose triacetate membranes in hollow fiber form (1978)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 22 (1978), S. 2307-2323 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A modification of the carrier gas method for measuring permeability of a hollow fiber to a vapor is described with particular application to water vapor permeation through asymmetric cellulose triacetate in hollow fiber from. Conventional methods are inadequate because the high flux of permeation vapor combined with its low pressure on the permeate side and the small diameter of the fiber lead to an excessive buildup of pressure in the permeate stream - in some cases so great as to render much of the fiber length ineffective. The method described in this paper involves the permeation from the outside to the inside of the fiber of a binary mixture consisting of the water vapor and a fairly highly permeable carrier (helium). There is a significant pressure drop along the fiber, but a theoretical treatment is presented to take this into account and to permit a determination of the vapor permeability. Experiments at 35°C over a range of water vapor pressures up to 1.7 cm Hg gave a water flux of 9 × 10-3 cc(S.T.P.)/cm2-sec-cm Hg, with an apparent slight decrease with increasing pressure. Over the same range of water vapor pressure the helium flux decreased from 2.3 × 10-4 to 1.85 × 10-4 cc(S.T.P.)/cm2-sec-cm Hg.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1978.070220822
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