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  • Wiley-Blackwell  (88)
  • 1985-1989  (58)
  • 1975-1979  (30)
  • 1920-1924
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  • 1
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 25 (1979), S. 615-622 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Characteristics of the gel layer were investigated by direct measurement of its concentration treating polyvinylalcohol and ovalbumin aqueous solutions, using cellulose acetate tubular ultrafiltration membranes. The concentration of the gel layer was not constant but a function of bulk concentration and feed velocity. The mass transfer coefficient obtained agreed with Deissler correlation. There was a definite correlation between the resistance of the gel layer and its concentration.
    Additional Material: 13 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 33 (1987), S. 1522-1532 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The Kinetics of the SO2-Na2CO3 reaction were studied at 353 to 413 K and atmospheric pressure with thermal gravimetric analysis data. Since the reaction is very fast, special precautions were taken to operate at conditions such that transport effects did not influence results. The data indicated that Na2SO3 was formed by two paths: direct reaction, and adsorption of SO2 followed by conversion of adsorbed SO2 to adsorbed CO2 and finally desorption to final product. Rate constants were evaluated for each step in the proposed mechanism. Product distribution predicted from the rate constants agreed well with the distribution calculated from the experimental data at temperatures from 353 to 413 K. At 413 K the results suggested a change in mechanism.
    Additional Material: 18 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 339-342 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 5 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 32 (1988), S. 669-676 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A continuous production process of maltotetraose was investigated by using immobilized maltotetraose (G4)- forming amylase (1,4-α-D-glucan maltotetraohydrolase, EC3.2.1.60) from Pseudomonas stutzeri adsorbed on a macroporous hydrophobic resin. The maximum reaction rate was obtained at 55°C and the activation energy of hydrolysis by immobilized G4-forming amylase was calculated to be 8.45 kcal/mol. The maltotetraose yield was greatly influenced by the flow rate of substrate solution, its concentration, and the immobilized enzyme activity. The newly defined factor “specific space velocity” was successfully introduced to normalize the operating parameters. Using this factor, the immobilized enzyme reactor then can be simulated and the operating dynamics can be determined.
    Additional Material: 8 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 33 (1989), S. 845-855 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The stability of immobilized maltotetraose (G4)-forming amylase (1,4-α-D-glucan maltoteraohydrolase, EC 3.2.1.60) from Pseudomonas stutzeri was investigated in both batch and continous processes. The inactivation process of the immobilized enzyme seemed to obey first-order kinetics, and the immobilized enzyme became more stable when coexisting with 20-30 wt % substrate and calcium ions. From intensive studies on the operational stability in the continuous process, the apparent half-life of G4 productivity in a constant-flow system was mainly affected by the reaction temperature, substrate concentration, and initial immobilized enzyme activity. A new factor, immobilized enzyme stability factor fs, was proposed to evaluate the half-life of the immobilized enzyme system.
    Additional Material: 11 Ill.
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  • 6
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die durch Polyvinylamin-Kupfer(II)chelat initiierte Polymerisation von Acrylnitril und Methylmethacrylat wurde in Dimethylsulfoxidlösung in Gegenwart sowie Abwesenheit von Tetrachlorkohlenstoff untersucht. Zum Vergleich damit wurde auch ein dimeres Chelat, d. h., 1,3-Diaminopropan-Kupfer(II)chelat als Starter gewählt. Es ergab sich, daß die Startfähigkeit dieses dimeren Chelats in Dimethylsulfoxid im Gegensatz zu derjenigen in Wasser höher als die des polymeren Chelats war. Das dimere Kupferchelat konnte die Polymerisation von Acrylnitril sogar in Abwesenheit von Tetrachlorkohlenstoff auslösen.
    Notes: The polymerization of acrylonitrile and methyl methacrylate initiated by polyvinylamine-copper(II) chelate was studied in dimethylsulfoxide solution, in the presence and absence of carbon tetrachloride. For comparison, the dimeric chelate(1,3-diaminopropane-copper(II) chelate) was also chosen as an initiator. The initiation activity of the dimeric chelate was found to be higher than that of the polymeric chelate in dimethylsulfoxide solution, different from the cases in aqueous media. The dimeric chelate could initiate the polymerization of acrylonitrile effectively, even in the absence of carbon tetrachloride.
    Additional Material: 8 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 132 (1985), S. 169-185 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Polyoxyethylendiglykolsäuren (PEO-Säuren) mit zahlenmittleren Molekularge-wichten von Mn = 8 400 (Ia), 3 300 (Ic) wurden als anti-elektrostatische Materialien for Nylon-6 (Ny6)-Fasern benutzt. Die 2 und 5 Gew.-% der PEO-Säuren enthaltenden Mischfasern wurden stufenweise aus der Schmelze der Mischung bei 260°C versponnen. Die Verarbeitbarkeit der [as-spun] Filamente bezüglich Spinnen und Ziehen war etwas schlechter als die der Ny6-Kontrollfasern. Während des Spinnvorgangs kam es zur Blockkondensation von I und Ny6 durch Reaktion der jeweiligen Endgruppen. Die erhaltenen Blockcopolymeren waren in der Filamentmatrix in Form grob verteilter kugelförmiger Partikel enthalten, die Inselstrukturen bildeten. Die Fasern zeigten gute antistatische Eigenschaften. Ihre Leistungen sanken in der Reihenfolge la 〉 Ib 〉 Ic, was parallel zur Größe, nicht zur Zahl der Inselstrukturen war. Die Festigkeit der Fasern mit 2 Gew.-% Ia und Ib war mit denen der Kontrollfaser vergleichbar. Die an Geweben aus diesen Fasern untersuchte Färbbarkeit wurde kaum beeinflußt. Außerdem zeigte sich, daß die antistatischen Eigenschaften auch beim Färben und den darauf folgenden wiederholten Waschvorgängen nicht verlorengingen. Der Grund dafür ist, daß I durch die oben erwähnte Kondensationsreaktion kovalent and die Ny6-Fasermatrix gebunden vorliegt.
    Notes: Poly(oxyethylene) diglycolic acids (PEO acids) with average molecular weights of Mn = 8 400 (Ia), 3 300 (Ib), and 1 000 (Ic) were used as blending anti-electrostatic agents for nylon 6 (Ny6) fibres. The blended fibres containing 2.0 and 5.0 wt.-% of the PEO acids were successfully spun by the melt-blend spinning process at 260°C. Processabilities of the spinning and the drawing of the as-spun filaments were little deteriorated compared with those of the Ny6 control. During the spinning block condensation of I and Ny6 occurred by reaction of their mutual end-groups. The block copolymers produced were distributed in the filament matrix as coarsely dispersed spheres to form sea-island structures. These fibres showed good antistatic properties; their performances were in the order of Ia 〉 Ib 〉 Ic, which was parallel to the size, not the number, of the islands. The tensile properties of the fibres containing 2.0 wt.-% of Ia and Ib were comparable with those of the control. The dyeabilities examined for their knits were not seriously affected, either. In addition, it was indicated that the performance of antistatic property was not lost at all after the dyeing and the subsequent repeated washings. This is because I is anchored covalently to the Ny6 fibre matrix by the condensation above.
    Additional Material: 3 Ill.
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  • 8
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die durch Kupfer(II)-chelate von Polyvinylamin, Polyvinylacetamid und Vinylamin-Vinylacetamid-Copolymeren initiierte Polymerisation von Acrylnitril wurde in Dimethylsulfoxidlösung untersucht. Es ergab sich, daß die Kupfer(II)-chelate der Vinylamin-Vinylacetamid-Copolymeren die Polymerisation von Acrylnitril sogar in Abwesenheit von Tetrachlorkohlenstoff glatt auslösen können, während die Kupfer(II)-chelate von Polyvinylamin und Polyvinylacetamid die Polymerisation erst in Anwesenheit von Tetrachlorkohlenst off auslösen. Die Polymerisationsaktivität scheint in Beziehung mit der Stabilität dieser Copolymer-Kupfer(II)-chelate zu stehen. Aus den Ergebnissen der Polymerisation und sichtbarer Spektroskopie wurde der Auslösungsmechanismus diskutiert.
    Notes: The polymerization of acrylonitrile initiated by copper(II) chelates of polyvinylamine, polyvinylacetamide and vinylamine-vinylacetamide copolymers was studied in dimethyl sulfoxide solution. The copper(II) chelates of vinylamine-vinylacetamide copolymers were found to initiate the polymerization of acrylonitrile effectively, even in the absence of carbon tetrachloride, while those of polyvinylamine and polyvinylacetamide initiate only in the presence of carbon tetrachloride. The polymerization activity was assumed to be closely related to the stability of these copolymer-copper(II) chelates. From the results of the polymerization and the visible spectroscopy, an initiation mechanism is discussed.
    Additional Material: 9 Ill.
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  • 9
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die radikalisch durch verschiedene α,ω-Diaminoalkan-Kupfer(II)-Komplexe initiierte Polymerisation von Acrylnitril wurde in Dimethylsulfoxidlösung untersucht. Es ergab sich, daß stabile Komplexe, wie der Äthylendiamin-Kupfer(II)-Komplex, die Polymerisation fast nicht auslösen, während die instabilen Komplexe von 1,5-Diaminopentan, 1,6-Diaminohexan und n-Butylamin die Polymerisation gut auslösen konnten.Die Polymerisationsauslösung wurde ferner spektrophotometrisch untersucht. Die Reduktion der Kupfer(II)-Komplexe zu Kupfer(I)-Komplexen während der Polymerisation wurde durch sichtbare Spektroskopie sowie die Kuproin-Färbungsmethode bestätigt. Die Reduktionsgeschwindigkeit steht eng mit der Stabilität der Diamin-Kupfer(II)-Komplexe in Beziehung. Aus den Ergebnissen wird der Initiierungsmechanismus diskutiert.
    Notes: Free radical polymerization of acrylonitrile initiated by various α,ω-diaminoalkane-copper(II) complexes was studied in dimethyl sulfoxide solution. It was found that the stable copper(II) complexes, like ethylenediamine copper(II) complex, could hardly initiate the polymerization, while the unstable copper(II) complexes, such as 1,5-diaminopentane, 1,6-diaminohexane and n-butylamine complexes could initiate the polymerization.Initiation was further studied spectrophotometrically. Reduction of the copper(II) to the copper(I) complexes was ascertained to occur during the polymerization by visible spectroscopy and cuproin coloration method. The rate of reduction was related closely to the stability of the diamine-copper(II) complexes. From the results the initiation mechanism was discussed.
    Additional Material: 10 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 138 (1986), S. 151-158 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Permeabilität von Alkalichloriden durch geladene Cellulosemembranen wurde bestimmt. Die geladenen Membranen wurden aus teilweise carboxymethylierter und carboxyethylierter Cellulose mit verschiedenen Substitutionsgraden hergestellt. Die Reihenfolge der Permeabilität wurde zu LiCl 〈 NaCl 〈 CsCl 〈 KCl bestimmt und auf die Verteilung und die Hydratation der Ionen zurückgeführt. Die Konzentrationsabhängigkeit der Permeabilität wurde durch die Teorell-Meyer-Sievers (TMS)-Theorie interpretiert. Die Effektivität der geladenen Gruppen in den Membranen wird durch die Bindung an das Gegenion erklärt.
    Notes: The permeation of alkali chlorides through charged cellulosic membranes was investigated. The membranes used were partially carboxymethylated and carboxyethylated cellulose with various degrees of substitution. The permeability coefficients were found to increase in a sequence of LiCl 〈 NaCl 〈 CsCl 〈 KCl. This sequence is explained by considering the partition and the hydration of the ions in these hydrophilic membranes. The dependence of the permeability on the salt concentration was interpreted by means of Teorell-Meyer-Sievers (TMS) theory. The effectiveness of the charged groups in the membranes is explained by the counterion binding mechanism.
    Additional Material: 3 Ill.
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