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  • 1
    Electronic Resource
    Electronic Resource
    Rubidium clock sound velocity meter (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 4679-4680 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A precision sound velocity meter has been made by adding a high stability rubidium oscillator to pulsed ultrasound instrumentation, where its stability and low noise is utilized as a quality time scale and a master clock, to which major timing events such as sound excitation, scope triggering, and time measurements are synchronized. Measuring operations are computer controlled. A reproducibility of ±0.005 m s−1 has been achieved in applications in research chemistry. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1322573
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  • 2
    Electronic Resource
    Electronic Resource
    An automated apparatus for ultrasound velocity measurements improving the pulse-echo-overlap method to a precision better than 0.5 ppm in liquids (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 1644-1648 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An improvement of the pulse-echo-overlap (PEO) method is proposed to make it accessible for computer control. The modification makes it possible to avoid the systematic and subjective errors of the original PEO method. A digital oscilloscope and a frequency synthesizer is controlled by a personal computer providing a fast automatic method for determination of ultrasonic wave transit times. Description of the method and the computer program, as well as the technical parameters is given. The Panametrics 5053A ultrasonic time intervalometer has been slightly modified to be applicable in the new configuration with a better precision. The 0.5 ppm precision velocity determination in water requires a 0.0003 °C level temperature control and reproducible wettability of the surface of the transducer. For both problems, a practical solution is proposed. Error analysis shows that the reproducibility of measurements is within 0.5 ppm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144853
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  • 3
    Electronic Resource
    Electronic Resource
    Partial molal volumes and compressibilities of carbohydrates in water (1978)
    Springer
    Journal of solution chemistry 7 (1978), S. 587-596 
    Details
    ISSN: 1572-8927
    Keywords: Water ; carbohydrates ; hydration ; additivity ; partial molal volume ; isentropic partial molal compressibility ; volume of ionization ; compressibility of ionization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The partial molal volumes and isentropic partial molal compressibilities of sugars, sugar alcohols, uronic acids, and some di- and trisaccharides in water have been measured at 25°C. The results suggest that the hydration of carbohydrates depends on the detailed stereochemistry of the solute and the way the solute molecule fits in the water structure. It seemed impossible at this stage to establish any additivity rules for the various functional groups or otherwise systematize the results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00646036
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  • 4
    Electronic Resource
    Electronic Resource
    Partial molal volumes of alcohols in propylene carbonate at 25°C (1976)
    Springer
    Journal of solution chemistry 5 (1976), S. 773-780 
    Details
    ISSN: 1572-8927
    Keywords: Partial molal volume ; group molal volume ; infinite dilution ; propylene carbonate (PC) ; scaled particle theory (SPT) ; intrinsic volume ; hydrogen bonding ; solute-solvent interactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The densities of the homologous series of alcohols and diols RnCH2OH (n=2−6), CH3CHOHRn (n=1−5), 1,2-propanediol, 1,3-1,4-, and 2,3-butanediol, 1,5-pentanediol, and 1,7-heptanediol dissolved in propylene carbonate have been measured at 25°C. The partial molal volumes at infinite dilution have been evaluated. Additivity of group molal volumes has been confirmed in propylene carbonate. The results have been discussed in relation to the same data in aqueous solution, and the scaled particle theory has been employed to calculate intrinsic volumes of the solutes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00651487
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  • 5
    Electronic Resource
    Electronic Resource
    Thermodynamic properties of peptide solutions: 14. Partial molar expansibilities and isothermal compressibilities of some glycyl dipeptides in aqueous solution (1996)
    Springer
    Journal of solution chemistry 25 (1996), S. 615-633 
    Details
    ISSN: 1572-8927
    Keywords: Partial molar isothermal compressibility ; partial molar expansibility ; aqueous solution ; peptide hydration ; glycyl dipeptides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The partial molar volumes at infinite dilution have been obtained for a series of glycyl dipeptides in aqueous solution at 15, 30, and 35°C. These results have been combined with data obtained at 25°C, that were reported earlier, to evaluate the partial molar expansibilities at infinite dilution for the dipeptides at 25°C. These quantities, along with the partial molar heat capacities and isentropic compressibilities at infinite dilution that were reported in previous studies, were used to derive the partial molar isothermal compressibilities at infinite dilution for the glycyl dipeptides at 25°C. The results obtained are rationalized in terms of the hydration of the constituent groups of the dipeptides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00972678
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  • 6
    Electronic Resource
    Electronic Resource
    Volume and compressibility changes of complex formation between 18-Crown-6 and NaCl, KCl, and CsCl in water (1978)
    Springer
    Journal of solution chemistry 7 (1978), S. 515-523 
    Details
    ISSN: 1572-8927
    Keywords: Partial molal volumes and compressibilities ; volume and compressibility changes of complex formation ; crown ether ; 18-Crown-6 ; aqueous
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The apparent molal volumes and compressibilities of NaCl, KCl, and CsCl in mixtures of 18-Crown-6 and water have been calculated from density and speed-of-sound measurements at 25°C. The partial molal volumes and compressibilities of the salts when all cations have formed complexes with 18-Crown-6 molecules have been evaluated. The sign and magnitude of the volume and compressibility changes of complex formation strongly suggest that the charge of the cation becomes very effectively screened by the crown ether.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01074868
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  • 7
    Electronic Resource
    Electronic Resource
    Water-alcohol interactions in the two-phase system water-alcohol-alkane (1984)
    Springer
    Journal of solution chemistry 13 (1984), S. 749-755 
    Details
    ISSN: 1572-8927
    Keywords: Water ; octane ; 1-alcohols ; 1,2-propanediol ; solubilities ; partition coefficients ; micelles ; water penetration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The system water-alcohol-alkane has been studied at 25°C as a possible model system for micelles. The solubility of water in pure alcohols and in octane in the presence of alcohol has been determined. The data suggest that water may enter the octane phase hydrogen bonded to the hydroxyl group of the alcohol. If this system has any bearing on aqueous micellar solutions, it seems possible that solubilized alcohol molecules may carry water into the micellar interior. Addition of 1,2-propanediol does not increase the water content in octane, probably because dimerization of the diol in octane is energetically more favorable than diol-water interactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00649012
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  • 8
    Electronic Resource
    Electronic Resource
    Thermodynamic properties of peptide solutions: 7. Partial molar isentropic pressure coefficients of some dipeptides in aqueous solution (1991)
    Springer
    Journal of solution chemistry 20 (1991), S. 1113-1127 
    Details
    ISSN: 1572-8927
    Keywords: Partial molar isentropic pressure coefficient ; speed of sound ; dipeptide ; aqueous solution ; side chain solvation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The partial molar isentropic pressure coefficients at infinite dilution, K S,2 o , have been determined for a number of dipeptides in aqueous solution at 25°C. For a series of dipeptides of sequence gly-X, where X is an amino acid with a neutral side chain, the K S,2 o values are all more negative than that for diglycine. The results are discussed in terms of the hydration of the side chains. There are significant differences in the K S,2 o values for sequence isomeric dipeptides. These differences can be rationalized in terms of the mutual interactions between the side chain and the ionic end groups in the dipeptides. Possible relationships between K S,2 o and V 2 o , the partial molar volume at infinite dilution, were investigated. For the dipeptides of sequence gly-X there is an interesting linear relationship between K S,2 o /V 2 o and V 2 o .
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00649100
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  • 9
    Electronic Resource
    Electronic Resource
    Thermodynamics of aqueous mixtures of 2-(2-Hexyloxyethoxy)ethanol at 5°C (1993)
    Springer
    Journal of solution chemistry 22 (1993), S. 1041-1062 
    Details
    ISSN: 1572-8927
    Keywords: Excess quantities ; reduced and apparent excess quantities ; molar volume ; molar isentropic compressibility ; ultrasonic speed ; alkyl poly(ethyleneglycol) monoether
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The densities and the ultrasonic speeds of the aqueous solutions of 2-(2-hexyloxyethoxy)ethanol (C6E2) were measured over the entire range of mole fractions at 5°C. Excess molar volumes V E were readily calculated from the densities. The densities, in combination with the ultrasonic speeds, furnish estimates of the molar (and excess molar) isentropic compressibilities K S and the deviations u D of the ultrasonic speeds from the values calculated for ideal mixtures. Radical changes in the mole fraction derivatives of the excess molar properties of the (C6E2 + water) system, in the vicinity of an amphiphile mole fraction of 0.003, indicate that C6E2 like C6E3 is capable of micelle formation. Our data have been compared with those reported earlier for (C4E2 +, C2E2 +, and C6E3 + water). We have employed both mass action and pseudophase approaches to data analysis, together with the four-segment model approach.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00647728
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  • 10
    Electronic Resource
    Electronic Resource
    Thermodynamic properties of peptide solutions. Part 15. Partial molar isentropic compressibilities of some glycyl dipeptides in aqueous solution at 15 and 35°C (1996)
    Springer
    Journal of solution chemistry 25 (1996), S. 1041-1053 
    Details
    ISSN: 1572-8927
    Keywords: Partial molar isentropic compressibility ; temperature dependence ; speed of sound ; dipeptide ; aqueous solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The partial molar isentropic compressibilities at infinite dilution,K s,2 o , have been obtained for eight glycyl dipeptides of sequence gly-X (X is an amino acid) in aqueous solution at the temperatures 15 and 35°C. The results have been combined with those obtained at 25°C, that were reported earlier, to evaluate the temperature dependences ofK s,2 o for the dipeptides in the temperature range 15 to 35°C. TheK s,2 o values for all the dipeptides are negative and increase (become more positive) with an increase in temperature. The slopes of the temperature dependences ofK s,2 o for the dipeptides with typically hydrophobic side-chains are significantly larger than those for dipeptides with hydrophilic side-chains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00972920
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