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  • extractive fermentation  (3)
  • nematic  (2)
  • 1990-1994  (5)
  • 1970-1974
  • 1
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 1845-1853 
    ISSN: 0887-624X
    Keywords: liquid crystalline ; networks ; epoxy ; thermotropic ; thermoset ; smectic ; nematic ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The processing of a new series of liquid crystalline (LC) epoxy networks was evaluated. Above the glass transition temperature, the low crosslink density networks could be mechanically aligned. The mechanically oriented networks readily lost orientation upon heating. Highly anisotropic liquid crystalline (LC) epoxy networks were also prepared by aligning the mesophase of the prepolymer during the curing process under the influence of a magnetic field. Orientation parameters (f) of 0.13 to 0.57 were achieved by these processes as determined by x-ray diffraction analysis. The ability of the magnetically aligned networks to retain their orientation above the glass transition temperature was determined by time-resolved x-ray diffraction. The stability of the alignment of these networks was found to depend on crosslink density. The effect of the anisotropy of these networks was investigated by measuring the coefficient of thermal expansion (CTE). In the aligned networks, there was a substantial reduction in CTE parallel to the direction of the applied field compared to the randomly oriented networks. © 1992 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 30 (1992), S. 1831-1843 
    ISSN: 0887-624X
    Keywords: liquid crystalline ; networks ; epoxy ; thermotropic ; thermoset ; smectic ; nematic ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This article describes the synthesis and characterization of a new series of liquid crystalline thermosets. Nematic epoxy-terminated oligoethers based on dihydroxy-α-methylstilbene were synthesized for this study. These prepolymers were crosslinked within the nematic mesophase using methylenedianiline. Depending upon the molecular weight and polydispersity of the oligoether, the crosslinking reaction resulted in networks with either a smectic or nematic molecular organization in contrast to the simple nematic phase of the oligoether. The formation of a smectic-like structure on curing was found to be related to the breadth of the prepolymer molecular weight. In those networks with a low crosslink density a clearing transition could be observed, whereas in the more highly crosslinked networks the molecular organization was frozen in until decomposition. The glass transition temperature of these LC networks rose as the crosslink density was increased, ranging from 35 to 152°C. In agreement with theory, the clearing transition of the networks was found to be dependent on the phase state during curing © 1992 John Wiley & Sons, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 37 (1991), S. 716-722 
    ISSN: 0006-3592
    Keywords: κ-carrageenan matrix ; Lactobacillus delbrueckii ; toxicity ; solvent diffusion ; extractive fermentation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The toxicity of an Alamine 336/oleyl-alcohol extraction system on Lactobacillus delbrueckii was investigated. It was shown that the solvent affected the cells through the water-soluble portion and the immiscible portion of the solvent. While immobilization significantly protected the cells from the immiscible solvent phase, the water-soluble part of the solvent still caused toxicity to the microorganisms due to diffusion of the solvent into the matrix. Adding soybean oil to the κ-carrageenan matrix could trap the diffusing solvent molecules, and therefore reduce the toxic effect from the water soluble portion of the solvent. The protective ability of soybean oil was quantified through mathematical modeling and experimentation.
    Additional Material: 6 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 37 (1991), S. 544-550 
    ISSN: 0006-3592
    Keywords: immobilization ; extractive fermentation ; Lactobacillus delbrueckii ; k-carrageenan ; mass transfer ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The use of immobilization in extractive lactic acid fermentation by Lactobacillus delbrueckii is preferred. In this article, the mathematical simulations to examine the influences of substrate and product transport were performed to assess the overall performance. The simulations showed that transport of the substrate in k-carrageenan beads was not a rate limiting factor. However, the model observed significant buildup of inhibitory product in large beads. The model was validated through comparisons with the experimental results. Finally, the model was used to predict the performance of the extractive fermentation under different operating strategies.
    Additional Material: 6 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 37 (1991), S. 1095-1100 
    ISSN: 0006-3592
    Keywords: extractive fermentation ; cell immobilization ; alamine 336 ; process modeling ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Lactic acid extractive fermentation was demonstrated using Alamine 336 in oleyl alcohol at acidic pH. The use of an efficient extraction system was possible through employment of the cell immobilization procedure. Process modeling was performed to relate the various process parameters such as flow rate, concentration, and pH. In experiments with 15% Alamine 336/oleyl alcohol, the bioreactor operation resulted in a higher productivity (12 g/L gel h) compared to that of a control fermentation (7 g/L gel h). Strategies for optimizing the extractive fermentation process were proposed considering both productivity and product recovery.
    Additional Material: 5 Ill.
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