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  • 1
    Electronic Resource
    Electronic Resource
    The ion product of H2O, dissociation constants of H2CO3 and pitzer parameters in the system Na+/H+/OH−/HCO 3 − /CO 3 2- /ClO 4 − /H2O at 25°C (1996)
    Springer
    Journal of solution chemistry 25 (1996), S. 327-343 
    Details
    ISSN: 1572-8927
    Keywords: Ion product of water ; carbonic acid ; dissociation constants ; NaClO4 solution ; iomic strength ; activity coefficients ; Pitzer model ; mixing parameters ; solution thermodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The ion product of water and the dissociation constants of carbonic acid have been determined in 0.1, 1.0, 3.0, and 5.0M NaClO4 at 25°C. The ion product of water K w ' has been evaluated by emf measurements with a combined glass electrode in NaClO4 solutions containing 0.001–0.1M HCLO4 or NaOH. The product K H ' K l ' K 2 ' of the Henry constant for CO2 and the dissociation constants for H2CO3 have been determined by titration of carbonate solutions equilibrated with pCO2 =10−3.52 atm, and K 2 ' has been evaluated by potentiometric titration and by measuring the H+ concentration at fixed HCO 3 − and CO 3 2- concentrations. The ion interaction (Pitzer) equations are applied to describe the constants K w ' , K 2 ' and K H ' H 1 ' K 2 ' as a function of the NaClO4 concentration. The experimental data are used to evaluate the mixing parametersΘ i/ClO 4 andΨ i/ClO 4 -/Na+ fori = OH -,HCO 3 - andCO 3 2-
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00972890
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  • 2
    Electronic Resource
    Electronic Resource
    Pitzer Parameters for the Pertechnetate Ion in the System Na+/K+/Mg2+/Ca2+/Cl−/SO 2 4 −/TcO − 4 /H2O at 25°C (1998)
    Springer
    Journal of solution chemistry 27 (1998), S. 107-120 
    Details
    ISSN: 1572-8927
    Keywords: Sodium pertechnetate ; magnesium pertechnetate ; potassium pertechnetate ; osmotic coefficients ; activity coefficients ; solubility ; seawater system ; Pitzer model ; binary parameters ; mixing parameters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Isopiestic vapor pressure experiments are performed at 25°C with aqueous Mg(TcO4)2 solutions and with ternary mixtures containing various combinations of NaTcO4, Mg(TcO4)2, NaCl, MgCl2, Na2SO4, and MgSO4. The osmotic coefficients of the binary solutions are used to evaluate the binary Pitzer parameters β(0), β(1), and CΦ for Mg(TcO4)2. We previously reported these parameters for NaTcO4. The binary parameters for KTcO4 and Ca(TcO4)2 are evaluated from solubilities of KTcO4 in KCl and CaCl2 solutions, respectively. The mixing parameters Θ TcO 4 − /Cl −, ΨM/TcO 4 − /Cl −, Θ TcO 4 − /SO 4 2− , ΨM/TcO 4 − /SO 4 2− , and ΨNa + /Mg 2+ /TcO4 2− are calculated from either osmotic coefficients or solubilities in the corresponding ternary mixtures. The evaluated set of Pitzer parameters predicts well the activity coefficients and solubilities of KTcO4 in multicomponent systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022625605743
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  • 3
    Electronic Resource
    Electronic Resource
    Thermodynamics of Cm(III) in Concentrated Salt Solutions: Carbonate Complexation in NaCl Solution at 25°C (1999)
    Springer
    Journal of solution chemistry 28 (1999), S. 447-462 
    Details
    ISSN: 1572-8927
    Keywords: Trivalent actinides ; curium ; americium ; solution thermodynamics ; carbonate complexation ; ionic strength ; Pitzer model ; concentrated solutions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The carbonate complexation reactions of Cm(III) were studied by time-resolved laser fluorescence spectroscopy in 0–6 m NaCl at 25°C. The ionic strength dependence of the stepwise formation constants for the carbonato complexes Cm(CO3) n 3−2n with n = 1, 2, 3, and 4 is described by modeling the activity coefficients of the Cm(III) species with Pitzer's ion-interaction approach. Based on the present results and literature data for Cm(III) and Am (III), the mean carbonate complexation constants at I = 0 are calculated to be: log β 101 o =8.1 ±0.3, log β 102 o =13.0 ± 0.6, log β 103 o =15.2 ± 0.4, and log β 104 o =13.0 ± 0.5. Combining these equilibrium constants at infinite dilution and the evaluated set of Pitzer parameters, a model is obtained, that reliably predicts the thermodynamics of bivalent actinide An(III) carbonate complexation in dilute to concentrated NaCl solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1022664013648
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  • 4
    Electronic Resource
    Electronic Resource
    Level structure of doubly odd154Ho (1994)
    Springer
    The European physical journal 350 (1994), S. 89-90 
    Details
    ISSN: 1434-601X
    Keywords: 23.20.Lv ; 27.70.+q
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract 154Ho was studied via141Pr(16O,3n) reaction at beam energy of 75 MeV. We found two new rotationally aligned bands made of neutron h9/2 and f7/2 orbitals coupled to a proton h11/2 orbital. As with several new high-spin states, up to I=20, the ground state band with odd parity starts to show anomalous signature splitting at I=13 in this doubly odd154Ho. The observed rotational bands in154Ho are quite consistent with the onset of collectivity which appears in general at neutron number of 87 in neutron-deficient rare-earth nuclei.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01290672
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  • 5
    Electronic Resource
    Electronic Resource
    High-spin states of odd-odd156Ho (1995)
    Springer
    The European physical journal 353 (1995), S. 119-120 
    Details
    ISSN: 1434-601X
    Keywords: 23.20.Lv ; 27.70.+q
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract High spin states in the nucleus156Ho have been studied via the fusion-evaporation reaction140Ce(19F,3nγ)156Ho at the beam energy of 82 MeV.γ-γ coincidences, Eγ, Iγ and excitation functions have been measured. With two rotationally-aligned bands identified as π[h11/2]ν [i13/2], we found two new bands with a signature splitting, whose structure is believed to arise from either ν[h9/2] or ν[f7/2] coupled to π[h11/2]. Our placement of γ rays belonging to these new bands suggests that the previously known level scheme should be corrected. We also found many new low-energy γ rays in the low excitation energy. As compared to154Ho, the present nucleus with two more neutrons becomes more collective, and shows well-observed rotationally-aligned bands with a clear signature splitting.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01295887
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  • 6
    Electronic Resource
    Electronic Resource
    Analysis of reaction injection molding process of polyurethane-unsaturated polyester blends. Part II: Mechanical properties (1987)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 27 (1987), S. 1252-1257 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 mechanical properties of polyurethane-unsaturated polyester interpenetrating polymer networks (IPNs) that were prepared by reaction injection molding (RIM) process were measured with variations In composition, cross-link density, and relative reaction rate. From dynamic mechanical analysis (DMA), it was found that the two component polymers had a good compatibility over the whole composition range. The tensile strengths of the blends were greater than those of the pure components and had a maximum value at 50/50 composition. The modulus of elasticity and surface hardness decreased and the impact strength increased as the polyurethane content was increased, but the changes were not high at low polyurethane content, below 50%. For higher cross-link density, the compatibility was enhanced and the mechanical properties were improved. When the reaction rates of the components were different, some extent of phase separation was found in DMA and the properties were affected adversely.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760271608
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  • 7
    Electronic Resource
    Electronic Resource
    Pressure drop for cocurrent downflow of gas-solids suspensions (1983)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 29 (1983), S. 353-360 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Pressure drop for a gas-solids suspension flowing concurrently downward in a 13-mm inside-diameter tube was investigated using 329-micron spherical glass beads in air. The gas Reynolds number varied from 0 to 30,000 with solids-loading ratios of up to 20 at a gas Reynolds number of 10,000. The frictional pressure drop for downflow was found to be a weaker function of the solids-loading ratio than the upflow case using data reported in the literature. Empirical correlation of the two-phase friction factor, in terms of the gas Reynolds number and a dimensionless parameter, CDEPD/[(1 - Ep)dp], showed that at high solids loadings, particles tend to stabilize the suspension flow. The dimensionless parameter seems to be applicable to a universal pressure drop correlation for solids-fluid systems, but requires further investigation.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690290302
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  • 8
    Electronic Resource
    Electronic Resource
    Heat transfer to gas-solids suspensions flowing cocurrently downward in a circular tube (1983)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 29 (1983), S. 306-312 
    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: Heat transfer to a gas-solids suspension flowing cocurrently downward in a 13-mm inside diameter tube with uniform heat-flux boundary conditions was investigated using 329-μm spherical glass beads in air. The gas Reynolds number varied from 0 to 30,000 with solids-loading ratios of up to 20 at a gas Reynolds number of 10,000. The suspension Nusselt number, defined in terms of the wall-to-gas mixed-mean temperature difference, decreased with increasing solids-loading ratio at high Reynolds numbers, while it changed little from the value for gas alone at low Reynolds numbers. A possible explanation is given by considering the effects of particles on the fluid mechanical properties of the gas. Asymptotic Nusselt numbers in downflow are compared with results of other investigations for upflow.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690290219
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  • 9
    Electronic Resource
    Electronic Resource
    Phase behavior of blends of poly(vinyl chloride) with an α-methyl styrene/acrylonitrile copolymer (1989)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 29 (1989), S. 581-585 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Poly(vinyl chloride), PVC, is shown to be miscible with an α-methyl styrene/acrylonitrile copolymer, αMSAN, containing 30 percent AN by weight using differential scanning calorimetry for blends prepared by several methods. Melt blending gave single Tg mixtures; whereas, solution techniques gave results that depended on the solvent choice and the manner in which it was removed. These blends do not phase separate on heating prior to significant PVC decomposition (∼250°C) in contrast to PVC/SAN blends which have much lower cloud points. Repulsion between α-methyl styrene and acrylonitrile units in the copolymer is the principal cause for miscibility of this system as shown by an analysis based on a binary interaction model using calorimetry data for low molecular weight liquid analog compounds.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760290903
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  • 10
    Electronic Resource
    Electronic Resource
    Reaction mechanisms of polyacrylonitrile on thermal treatment (1993)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 33 (1993), S. 1452-1457 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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 high-temperature radical scavenger, 2,2-diphenyl-l-picryl hydrazyl (DPPH), has been used to study the reaction mechanisms of polyacrylonitrile (PAN) on thermal treatment. The effect of DPPH on the cyclization reaction of PAN in both air and nitrogen, investigated by differential scanning calorimetry (DSC), helped to verify the proposed reaction mechanisms, i.e., the free radical and the ionic ones. For PAN homopolymer, the peak temperature of the reaction exotherm shifted to higher temperatures and the heat of reaction was decreased with increasing DPPH concentration. For PAN copolymer with methylacrylate and itaconic acid, however, the effects of DPPH on DSC thermograms were insignificant. The effects of IPPH suggest that the reaction of the nitrile groups proceeds by free radicals for the homopolymer while by ions for the copolymer. The activation energies for the thermal reactions of PAN in both air and nitrogen were also estimated by the dynamic DSC method, and they proved to be highly dependent on reaction mechanism, environment of thermal treatment, and DPPH concentration.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760332203
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