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  • 1995-1999  (2)
  • 1970-1974  (3)
  • 1955-1959  (1)
  • 1935-1939
  • 1910-1914
  • Polymer and Materials Science  (4)
  • carbon dioxide  (2)
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  • 1
    ISSN: 1573-2967
    Keywords: carbon dioxide ; plume ; pH ; random walk ; diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A method to evaluate aquatic mortality given a pollutant distribution is presented and applied to several sample low pH plumes representing various ocean CO2 disposal schemes. The method is an improvement over current analysis because it integrates the mortality due to time‐varying exposure to low pH with the probabilistic experiences of passive organisms subject to turbulent lateral diffusion as they pass through the plume. For the examples presented, the plume was discretized laterally into lanes and longitudinally by time steps, and a random walk model accounting for the scale‐dependent nature of relative diffusion was used to simulate the organism pathways over one time step. From these simulations, the probability that an organism will be in a given lane, $$\dot \jmath $$ , one time step after it starts from an initial lane, $$i$$ , was determined for all combinations of $$i$$ and $$\dot \jmath $$ . These probabilities were used to find the number of organisms following each of the possible pathways, and the mortality to the organisms due to their time varying exposure to low pH was determined by using the toxicity model described in part I of this paper. The integrated method allows the impact of the plume to be described in terms of total organism mortality as well as spatial deficit of organisms.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-2967
    Keywords: carbon dioxide ; sequestration ; plume ; pH ; toxicity ; zooplankton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Feasibility studies suggest that the concept of capturing CO2 from fossil fuel power plants and discharging it to the deep ocean could help reduce atmospheric CO2 concentrations. However, the local reduction in seawater pH near the point of injection is a potential environmental impact. Data from the literature reporting on toxicity of reduced pH to marine organisms potentially affected by such a plume were combined into a model expressing mortality as a function of pH and exposure time. Since organisms exposed to real plumes would experience a time‐varying pH, methods to account for a variable exposure were reviewed and a new method developed based on the concept of isomortality. In part II of this paper, the method is combined with a random‐walk model describing the transport of passive organisms through a low pH plume leading to a Monte‐Carlo‐like risk assessment which is applied to several candidate CO2 injection scenarios.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 14 (1970), S. 747-756 
    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 isothermal decomposition of a phenolic resin in a phenolic-carbon cloth composite was measured at approximately 0.1 to 0.2 torr over the temperature range of 105°-718°C. The kinetics are initially first order and, in the later stages, second order. An analytic technique is provided for calculating the maximum quantity of resin which will volatilize during decomposition, thereby obviating the necessity of measurements for extended time periods. The amount of resin available for volatilization during decomposition varies with temperature and is in equilibrium with resin, which does not volatilize. Plots of the equilibrium constant versus the reciprocal absolute temperature show that two equilibria are involved: one which predominates up to 352°C and the other above this temperature. The heats of reaction are 2.2 and 15.3 kcal/mole. The first value is associated with hydrogen bonding and the second with decomposition and oxidation activation energies.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 15 (1971), S. 91-103 
    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 isothermal decomposition of a phenolic resin in a phenolic-carbon cloth composite was measured in air at 0.1 to 0.2 torr over the temperature range 104-718°C. Two decomposition rate relationships are presented that can be used to predict decomposition. One assumes two second-order consecutive rate-controlling reactions, and the other assumes a diffusion-limited second-order reaction. Two rate constants govern each relationship, one being operative during the initial decomposition stages, and the other during the final stages. Evidence is presented to support the applicability of both relationships to predict decomposition over the entire temperature range studied. Arrhenius plots of the rate constants consist of several segments linearly connected. Activation energies and frequency factors computed from these segments cover a broad range of values. The activation energies are used to correlate the temperature ranges with the predominant products formed in these ranges.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 163-173 
    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: ABA-type block polymers of styrene (monomer A) and isoprene or butadiene were prepared using two commercially available dilithium adducts of isoprene as initiators. One (DiLi-1) was predominantly dilithio diisoprene and contained a small amount of dimethyl ether (ether/Li 〉 1.0). The second (DiLi-1 C.E.) was a higher molecular weight version of DiLi-1, containing about seven isoprene units per molecule. It contained only a trace of dimethyl ether (ether/Li 〈 0.1). Polymers were made by charging all of the monomers at the start of the reaction. The diene polymerized first, incorporating some styrene. When the diene was consumed, the difunctional polymer chains then added a block of nearly pure polystyrene at each end. Thus an ABA-type polymer was synthesized in one step. These polymers show the usual behavior of pseudo-vulcanized elastomers. Their stress-strain curves are given. The SBS polymers had the higher tensile strengths. None had tensile strengths as high as SBS or SIS polymers made with n- or sec-butyllithium. It was shown that the diene blocks contain appreciable amounts of styrene. This leads to more compatibility between the A and B blocks; it also shortens the styrene blocks compared to the theoretical lengths of “pure” blocks. Both effects can lead to loss of tensile strength. Microstructures of the diene homopolymers made with these initiators are also given.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 28 (1958), S. 129-150 
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Study of the diffusion in polymers of molecules comparable in size and structure to the segments of the chain molecules is suggested as a means of securing information on structure and molecular friction forces in polymers. A convenient method for measuring the diffusivity in polymers of such compounds tagged with C-14 was devised and used to study the diffusivity of octadecane, octadecanol, stearic acid, and octadecyl stearate for a range of temperatures in polymers including natural rubber, GR-S, polybutadiene, polyisoprene, and polyisobutylene. Diffusivities were independent of concentration for the range used. The diffusivities of straight chain hydrocarbons in natural rubber appear to vary inversely as the molecular weight of the diffusing compound. Evidence was found for association effects in the diffusion of stearic acid in natural rubber. Activation energies for diffusion of the compounds were quite similar in any one polymer and of the same order as reported for low molecular weight hydrocarbons and for viscous flow. Larger differences in activation energies were observed for diffusion in the different polymers. Correlations were observed for the diffusivities of octadecane in a series of polymers with their densities and thermal expansivities, especially the latter. Some study was given to the effect on the diffusivity of octadecane of such parameters as polymer unsaturation, solution viscosity, molecular weight, and crosslink density. The diffusivity of octadecane in natural rubber had a pronounced maximum as a function of crosslink density, coinciding with the maximum in tensile strength. Possible implications of this are discussed. The diffusivities of octadecane in a series of elastomers were studied in relation to the internal frictional losses observed for 60 cps vibrations over a range of temperatures. It was concluded that frictional forces deduced from the diffusivity measurements have some correspondence to high frequency viscoelastic phenomena which involve small units of structure comparable in size to the segments of the polymer molecules.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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