MEASUREMENTS OF ISOBARIC SPECIFIC HEAT CAPACITY FOR AQUEOUS MIXTURES AT HIGH PRESSURES
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Accession number;07A0043234
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| Title;MEASUREMENTS OF ISOBARIC SPECIFIC HEAT CAPACITY FOR AQUEOUS MIXTURES AT HIGH PRESSURES |
| Author;
FUJITA IKUO
(Keio Univ., Graduate School, JPN)
TANAKA KATSUYUKI
(Iwaki Meisei Univ., JPN)
UEMATSU MASAHIKO
(Keio Univ., Faculty of Sci. and Technol., JPN)
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Journal Title;Thermophys Prop
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Journal Code:X0031A
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ISSN:0911-1743
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VOL.27th;NO.;PAGE.95-97(2006)
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| Figure&Table&Reference;FIG.5, TBL.1, REF.5 |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;We have developed a new calorimeter for measurements of isobaric specific heat capacity for fluids and fluid mixtures by the thermal relaxation method. The calorimeter was designed in order to measure the isobaric specific heat capacity in the temperature rage from 250K to 473K, at pressures from 0.1MPa to 20MPa. The calorimeter is a cylindrical form with metal-bellows as a sample container that makes possible to keep the sample pressure constant. A heater is placed on the bottom of the sample container. The sample temperature increments are measured by five platinum resistance thermometers. Nitrogen gas filled between sample container and pressure vessel has functions of adiabatic and pressure media. The pressure vessel is immersed in a thermostatted oil bath whose temperature kept constant at within .+-.5mK. In this study, measurements of the isobaric specific heat capacities for {(1-x)CH3OH+xH2O} with x=(0.0000, 0.2057, 0.5051, 0.6523, 0.7394, 0.8064, 0.8990, 0.9504) were carried out by the calorimeter at T=(280, 320, 360)K in the pressure range from 0.1MPa to 15MPa. The experimental uncertainties estimated at a 95% confidence level are from 1.0% to 7.6%. The uncertainty in cp measurements increases with increasing pressure and decreasing temperature. The present cp measurements at constant temperature show strong mole fraction dependence with the maximum for methanol-water mixtures, and the maximum shifts to smaller values of mole fraction with increasing temperature. Pressure dependence of the present measurements are insignificant. Temperature dependence increases with decreasing mole fraction. We compared our results for aqueous methanol mixtures at 5MPa with the measurements by Dettmann et al. and good agreement between these measurements is confirmed. (author abst.) |
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