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  • 1
    Electronic Resource
    Electronic Resource
    Simultaneous effect of macromixing and micromixing on growth processes (1971)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 17 (1971), S. 689-696 
    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: Interaction of macromixing and micromixing in microbiological flow reactors based on a kinetic model of the Michaelis-Menten type has been treated by considering two general types of flow systems: the system of n continuous stirred-tank reactors in series (n-CSTR's in series) and the series combination of a plug-flow reactor and a continuous stirred-tank reactor. Systematic schemes to describe the micromixing conditions of a reactor system are presented. Additional micromixing states are considered besides those proposed by Kramers and those proposed by Zwietering if the systems are employed as empirical models of a flow system. When the number of stirred-reactor units in the system of n-CSTR's in series is small, micromixing has a significant effect on the growth processes. As the number of reactor units increases, the micromixing effect on the growth processes decreases. The effect of micromixing is also important for a system described by a series combination of a plug-flow reactor and a continuous stirred reactor. In addition, the exit concentrations from the system having the same residence time distribution and the same degree of segregation may be different from each other. Information obtained in this study is pertinent in the design of biological flow reactors and sewage treatment systems.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690170336
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  • 2
    Electronic Resource
    Electronic Resource
    Flow patterns and some holdup experimental data in trickle-bed reactors for foaming, nonfoaming, and viscous organic liquids (1978)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 24 (1978), S. 357-360 
    Details
    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: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690240230
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  • 3
    Electronic Resource
    Electronic Resource
    Isolation of a yeast-lyzing Arthrobacter species and the production of the lytic enzyme complex in batch and continuous-flow fermentors (1977)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 19 (1977), S. 879-899 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A gram-negative bacterium strongly lytic toward living cells of the food yeast Saccharomyces fragilis was isolated by continuous-flow enrichment from compost. The organism was identified as a species of Arthrobacter. The extracellular lytic enzyme complex produced by this bacterium contained β-1,3-glucanase, mannan mannohydrolase, and proteolytic activities. The polysaccharases were inducible by whole yeast cells. In chemostat cultures on chemically defined media, synthesis of the polysaccharases was very slight and only detectable at dilution rates below 0.02 hr-1. Enzyme production in defined media was not solely dependent on growth rate but also was influenced by the growth limiting substrate and the culture history. The production of individual depolymerases and of the lytic activity was studied in batch and chemostat cultures containing yeast as the limiting substrate. The maximum specific growth rate of the Arthrobacter under these conditions was 0.22 hr-1. β-1,3-Glucanase and proteolytic activities were synthesized by exponentially growing bacteria but maximum lytic titers did not develop until the specific growth rate was declining, at which time mannan mannohydrolase syntheses was induced. In yeast limited chemostats polysaccharase syntheses were greatest at the lowest dilution rates examined, namely 0.02 hr-1. Further optimization of enzyme production was achieved by feeding the Arthrobacter culture to a second-stage chemostat. A comparison of lytic enzyme productivities in batch and chemostat cultures has been made.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260190608
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  • 4
    Electronic Resource
    Electronic Resource
    Internal field emission in carbon black-loaded natural rubber vulcanizates (1962)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 6 (1962), S. 651-655 
    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: The nonohmic behavior of carbon black-loaded natural rubber viilcanizates was studied. Three samples contained high-abrasion furnace black (HAF) in good, moderate, and poor dispersion. Another sample contained a good dispersion of medium thermal black (MT). The nonohmic behavior of the poor HAF dispersion and that of the MT dispersion could be interpreted as due to internal field emission acroM insulating gap widths of 2 and 2.5 μ. The existence of such gaps waa confirmed by electron micrographs. No clear evidence of internal field emission could be obtained for the good and moderate HAP dispersions where, according to electron micrographs, the gaps are much narrower. There is some indication that the degree of diapersion can be correlated with field emission characteristics.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1962.070062408
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  • 5
    Electronic Resource
    Electronic Resource
    Singlet-triplet splittings as obtained from the Xα-scattered wave method: A theoretical analysis (1975)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 9 (1975), S. 143-148 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The theoretical determination of singlet-triplet splittings of the excited states of closed-shell molecules is discussed with emphasis on the use of the Xα-scattered wave method. With this method, splittings can be computed in two independent ways. Both will have corrections due to orbital relaxation effects. The singlet-triplet splittings obtained with the Xα-scattered wave method for several large organic molecules are reviewed. It is seen that the results using the two splitting formulas differ by a large amount; in fact, they differ by the magnitude of the computed splitting. We provide a criterion for choosing the results obtained with one method over the other by showing that they both give upper bounds to the best result obtainable within the framework of the model. However, because of the large differences between the two methods, the quantitative value of the splitting should be viewed with caution.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560090114
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  • 6
    Electronic Resource
    Electronic Resource
    Interactions and self-organization of nucleic bases, nucleotides, and polynucleotides into ordered structures. Effect of ionization and solvent salt compositionPresented at the International Conference on Quantum Chemistry, Biology, and Pharmacology held at Kiev, U.S.S.R., September 1978. (1980)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 17 (1980), S. 339-359 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper summarizes our findings on the effects of protons and neutral salt ions on intermolecular interactions and the self-organization of nucleotide systems in aqueous media, both at monomer and polymer levels. To gain quantitative information about these processes, methods were developed to determine the thermodynamic parameters of monomer association from the data obtained by various experimental techniques (NMR, UV spectroscopy, and spin labeling) and to estimate the individual contributions of base stacking and H-bonding in ordered structures of polynucleotides and their complexes. The main results obtained using these methods are as follows. (i) A difference was discovered in the effects of positive and negative charges on the stacking interaction between ionized and neutral molecules of nucleic heterocycles. Protonation strongly decreases the heterocycle ability to form ordered stacks whereas deprotonation slightly affects stacking. (ii) Base-phosphate interaction, which has not yet really been investigated, was studied. This interaction, along with base stacking, governs nucleotide association in water media. It appears upon protonation of the base moiety and increases with decreasing ionic strength. (iii) Base stacking was found to become stronger under the action of salt anions stabilizing the water structure and it became weaker under the action of destabilizing salt anions, both in monomer and polymer systems, which is indicative of an indirect mechanism of the anionic effects. It is essential that small salt ion additives acting by such a “distance” mechanism can affect the formation of ordered structures in nucleotide systems as strong as the direct interaction of the bases with protons. (iv) The results obtained suggest that an increase in solvent entropy upon the self-organization of nucleotide systems in aqueous media may be an important factor promoting these processes. (v) As follows from our data, specific weakening or strengthening of intermolecular interactions by protons and salt ions at small, physiological-range changes in pH or solvent salt composition seems to be an effective regulatory mechanism for the functioning of nucleotide systems.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560170217
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  • 7
    Electronic Resource
    Electronic Resource
    Geometry optimization using local-density functional methods: Numerical aspects (1988)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 34 (1988), S. 77-84 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The need to perform a numerical integration of the exchange-correlation functional because of its non-analyticity severely complicates the accurate application of local-density functional methods to molecules and clusters. The optimal choice of grid points for this integration and the estimation of the error made by the choice are subtle considerations. In particular, because the position and/or weighting of each grid point must change when the nuclear positions change, these errors are most noticeable when different geometries are compared. We have determined a method of grid point selection and weighting that reduces these errors. We have also determined a simple method of estimating the extent of the error made in the particular density of points used for the grid. These results are illustrated for a selection of small molecules.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560340813
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  • 8
    Electronic Resource
    Electronic Resource
    Dissociative adsorption and associative desorption of H2 on a flat surface (1991)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 40 (1991), S. 641-657 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A quantum mechanical time-dependent method was used to study the dynamics of dissociative adsorption and associative desorption of H2 on a flat, static surface. We used a two-dimensional model in which the molecular axis was held parallel to the surface and the diatom internuclear separation and distance above the surface were the dynamic variables. A modified London-Eyring-Polanyi-Sato (LEPS) potential described the molecule-surface interactions. The wave function for the molecule was represented by its values on a spatial grid of points. The wave function was propagated by expanding the time evolution operator in a series of Chebyshev polynomials and using the properties of the Fourier transform to calculate the kinetic energy. The computational requirements of the problem were significantly reduced by using an L-shaped grid which deletes a large number of points where it is known a priori that the wave-function amplitude vanishes. State-to-state transition probabilities were calculated as a function of the initial translational and vibrational energy for potentials with early, late, and intermediate barriers. The location of the barrier has a strong effect on the energy threshold for reaction and on the distribution of energy between vibration and translation in the products.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560400857
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  • 9
    Electronic Resource
    Electronic Resource
    Density functional theory including Van Der Waals forces (1995)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 56 (1995), S. 247-255 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A progress report is given of an extension of the density functional formalism to include long-range interactions such as van der Waals or dispersion forces. This is done by proving a general expression for the so-called exchange-correlation energy to contain and to describe such interactions just as well as any other treatment. The proper long-range forms of the interactions are derived explicitly in the cases of two neutral atoms, an atom outside a metal surface, and two parallel metal surfaces. The long-standing problem of treating the attractive and repulsive forces on the same footing in this way gets a solution. For practical calculations, an approximate form, based on an analysis in the weakly inhomogeneous limit and on a limiting form of the three-point function given by Rapcewicz and Ashcroft, is proposed and applied to some prototype cases. © 1995 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560560410
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  • 10
    Electronic Resource
    Electronic Resource
    Estimation of some parameters of the exchange mechanism of luminescence decay (1979)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 16 (1979), S. 931-935 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The rates of variations of the relative yield (αη) and decay time (ατ) with the acceptor concentration (CA) have been calculated in the vicinity of CA = 0. On the basis of the equations obtained, the ratio αη/ατ has been found and a simple scheme of experimental data analysis proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560160426
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