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  • 11
    Electronic Resource
    Electronic Resource
    Square-Free Algorithms in Positive Characteristic (1995)
    Springer
    Applicable algebra in engineering, communication and computing 7 (1995), S. 1-14 
    Details
    ISSN: 1432-0622
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics , Technology
    Notes: Abstract.  We study the problem of the computation of the square-free decomposition for polynomials over fields of positive characteristic. For fields which are explicitly finitely generated over perfect fields, we show how the classical algorithm for characteristic zero can be generalized using multiple derivations. For more general fields of positive characteristic one must make an additional constructive hypothesis in order for the problem to be decidable. We show that Seidenberg’s Condition P gives a necessary and sufficient condition on the field K for computing a complete square free decomposition of polynomials with coefficients in any finite algebraic extension of K.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01613611
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  • 12
    Electronic Resource
    Electronic Resource
    Apparent molar heat capacity and relative enthalpy of aqueous NaOH between 323 and 523K (1988)
    Springer
    Journal of solution chemistry 17 (1988), S. 481-497 
    Details
    ISSN: 1572-8927
    Keywords: Heat capacity ; enthalpy of dilution ; aqueous NaOH ; aqueous Na2SO4 ; high temperature ; flow calorimeter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The apparent molar heat capacity, C p,ϕ, of aqueous NaOH has been measured at temperatures between 50 and 250°C and molalities from 0.05 to 1.5 mol-kg−1. Enthalpies of dilution ΔLϕ were also determined at 99°C and apparent molar relative enthalpies Lϕ were calculated up to 1.9 m. Measurements were performed by means of a flow calorimetric apparatus constructed in our laboratory and standardized for C p,ϕ and ΔLϕ with aqueous Na2SO4 and with the formation of water from its ions, respectively. Characteristics and performance of this calorimeter are described in detail. Pitzer's semiempirical equations are used for the representation of the results and a general fitting of C p,ϕ data is reported using also recent literature values measured between 4 and 55°C. The fitted parameters are finally utilized, through an integration procedure, to derive a general equation to calculate Lϕ at any temperature between 4 and 250°C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00647315
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  • 13
    Electronic Resource
    Electronic Resource
    Apparent molar heat capacity and relative enthalpy of aqueous sodium hydroxoaluminate between 323 and 523 K (1989)
    Springer
    Journal of solution chemistry 18 (1989), S. 447-461 
    Details
    ISSN: 1572-8927
    Keywords: Heat capacity ; enthalpy of dilution ; aqueous NaAl(OH)4 ; high temperature ; flow calorimeter ; aluminum ion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The apparent molar heat capacities, Cp,ϕ, of alkaline aqueous solutions of aluminum ion in excess NaOH have been measured at temperatures between 50 and 250°C in the overall molality range 0.3–1.7 mol-kg−1. Enthalpies of dilution, ΔLϕ, have also been determined at 99°C and apparent molar relative enthalpies, Lϕ, were calculated starting from 2.16 mol-kg−1 as the maximum concentration. Measurements of the above quantities have been performed by means of a differential flow calorimeter built in our laboratory and already described. The thermodynamic data obtained and the corresponding quantities for aqueous NaOH previously determined have been fitted to the equations of the Pitzer ionic interaction model to obtain parameters relative to aqueous NaAl(OH)4. These parameters permit the calculation of Cp,ϕ, and Lϕ for this species over the examined range of temperatures and concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00657332
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  • 14
    Electronic Resource
    Electronic Resource
    Heat capacities of aqueous mixed electrolyte solutions at high temperatures. Application of the Pitzer equations to the mixed system K−Na−Cl−SO4 (1986)
    Springer
    Journal of solution chemistry 15 (1986), S. 349-362 
    Details
    ISSN: 1572-8927
    Keywords: Heat capacity ; high temperature ; mixed electrolytes solution ; sodium chloride ; potassium chloride ; sodium sulphate ; potassium sulphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Specific heats at constant pressure for the mixed system K/Na/Cl/SO4 in H2O have been obtained from heat content measurements by means of a drop calorimeter between 60 and 220°C over the salt concentration range 0.5–5m, with ionic strengths up to 7.5. Measurements have also been made on aqueous K2SO4 solutions in the same temperature range between 0.3 and 1.6m. The heat capacities of the quaternary system were represented using the semiempirical Pitzer equations neglecting the mixed interaction terms as a first approximation. A comparison of experimental with calculated data shows that the ability of this method to describe the system is satisfactory even at rather high concentrations, but only for solutions of low sulphate ion content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00648889
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  • 15
    Electronic Resource
    Electronic Resource
    Compatibility Range in Polymer Mixtures. An approach using analogue calorimetry and group contribution procedures (2000)
    Springer
    Journal of thermal analysis and calorimetry 62 (2000), S. 135-151 
    Details
    ISSN: 1572-8943
    Keywords: analogue calorimetry ; binary and ternary mixtures ; excess enthalpies ; group contributions ; model compounds ; polymer blends
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The mixing enthalpies of blends of polymethylmethacrylate (PMMA) with poly(styrene-co-acrylonitrile) (SAN) were investigated by analogue calorimetry through the determination of the excess enthalpies of pseudobinary model mixtures corresponding to the addition of methyl-i-butyrate to a binary mixture of acetonitrile or propionitrile plus toluene or ethylbenzene. A group contribution procedure, based on UNIQUAC equation, was also devised and the polymeric mixing enthalpies were calculated from properly defined group contributions. Enthalpies for polymeric interactions were introduced into the Flory-Huggins equation and the miscibility window of PMMA-SAN mixtures was calculated. The results show a qualitative agreement with the experimental miscibility data and indicate that both the analogue calorimetry and the group contribution procedures yield correct results when acetonitrile, and not propionitrile, is chosen as the model for the polyacrylonitrile repeat unit of the copolymer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010118929599
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  • 16
    Electronic Resource
    Electronic Resource
    Excess Molar Enthalpies of the Ternary Systems (Acetonitrile+methyl Isobutyrate+Toluene) and (Propionitrile+methyl Isobutyrate+ethylbenzene) at 298.15 K (2000)
    Springer
    Journal of thermal analysis and calorimetry 61 (2000), S. 377-388 
    Details
    ISSN: 1572-8943
    Keywords: analogue calorimetry ; excess enthalpies ; mixtures ; model compounds ; polymer blends
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Excess molar enthalpies were measured at 298.15 K with a flow calorimeter built in our laboratory for the two ternary systems (acetonitrile+methyl isobutyrate+toluene) and (propionitrile+methylisobutyrate+ethylbenzene). Experimental data were nicely predicted by some empirical andsemi empirical procedures, exception made for UNIFAC group contribution method. The latter equation proved unsatisfactory for all mixtures containing methyl isobutyrate. The first ternary set proved a good model system to simulate mixing enthalpies reported in the literature for mixtures of poly(styrene-co-acrylonitrile) with polymethylmethacrylate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010105131141
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