A Reappraisal of the Critical Constants for Water

1965 ◽  
Vol 87 (2) ◽  
pp. 266-274 ◽  
Author(s):  
O. C. Bridgeman ◽  
E. W. Aldrich
Keyword(s):  
Temperature Scale ◽  
Enthalpy Of Vaporization ◽  
National Bureau ◽  
Calorimetric Data ◽  
Saturated Liquid ◽  
Vapor Pressure Equation ◽  
Practical Temperature ◽  
Practical Temperature Scale ◽  
Thermodynamic Scale ◽  
Critical Constants

A reappraisal of the critical constants for water has been made, based on the calorimetric data of the National Bureau of Standards for saturated liquid and vapor. The temperature tc at which the enthalpy of vaporization becomes zero was found to be 374.02 C on the International Practical Temperature Scale or 374.136 C on the thermodynamic scale, within a few thousandths of a deg C. From the experimental data for γ = VV·TdP/dT and β = VL·TdP/dT, the value of γc = βc at the critical point where γ − β = L = 0 was found to be 541.382 ± 0.065 int.J/g. Using the present authors’ vapor-pressure equation for water, the critical volume Vc becomes 3.1547 cm3/g and the critical pressure Pc equals 225.268 kg/cm2, at a temperature of 374.02 C (IPTS). A comparison is made with the values reported by previous investigators.

scholarly journals 29a. Working Group on Absolute Spectrophotometry

1970 ◽  
Vol 14 (1) ◽  
pp. 329-331
Author(s):  
J. B. Oke
Keyword(s):  
Melting Point ◽  
Temperature Scale ◽  
Spectral Energy Distribution ◽  
Thermodynamic Temperature ◽  
Spectral Energy ◽  
Light Sources ◽  
National Bureau ◽  
Practical Temperature ◽  
Practical Temperature Scale ◽  
Standard Lamp

Two new and independent determinations of the absolute spectral energy distribution in αLyr have been completed during the last three years. The first of these by Hayes has been published in part (Wolff, Kuhi and Hayes, 1968). It was done at the Lick Observatory using the Crossley reflector and two ribbon-filament standard lamps. His published results are based on the old practical temperature scale which is based on a melting point for gold of 1336·16K. The new scale has been adjusted to agree as well as possible with the thermodynamic temperature scale and is based on 1337·59K for the melting point of gold. Hayes’ results have been adjusted to this new scale and are shown in Table 1. The numbers listed are — 2·5 log fv + const, when fv is the flux from αLyr in ergs s-1 cm-2 Hz-1. The results are normalized to 0·000 at λ5556.The new calibration by Oke and Schild was carried out on Palomar Mountain. A four inch reflecting telescope was built and mounted with the prime focus scanner which was built for the 200-inch telescope. Three light sources were used (1) a ribbon-filament standard lamp calibrated with an accuracy of 2 % by the National Bureau of Standards was used from λ3300 to λ8000.

The specific heats of copper, silver, and gold below 300 K

1987 ◽  
Vol 65 (9) ◽  
pp. 1104-1110 ◽  
Author(s):  
Douglas L. Martin
Keyword(s):  
Specific Heat ◽  
Debye Temperature ◽  
Temperature Scale ◽  
Specific Heats ◽  
Practical Temperature ◽  
Practical Temperature Scale

Specific-heat measurements on silver and gold in the 15–320 K range are reported and compared with earlier measurements on these metals. The present results together with recent measurements on copper (D. L. Martin, Rev. Sci. Instrum. 58, 639 (1987)) are analyzed in terms of the Debye temperature. The results suggest a negative anharmonic contribution to specific heat for silver and gold. Structure in the results for all three metals below 60 K is consistent with known imperfections in the International Practical Temperature Scale of 1968.

scholarly journals The succinonitrile triple-point standard: a fixed point to improve the accuracy of temperature measurements in the clinical laboratory.

1983 ◽  
Vol 29 (7) ◽  
pp. 1380-1384 ◽  
Author(s):  
B W Mangum
Keyword(s):  
Fixed Point ◽  
Triple Point ◽  
Temperature Scale ◽  
Clinical Laboratory ◽  
Freezing Behavior ◽  
Temperature Measurements ◽  
Point Temperature ◽  
Practical Temperature ◽  
Practical Temperature Scale ◽  
Triple Point Temperature

Abstract In an investigation of the melting and freezing behavior of succinonitrile, the triple-point temperature was determined to be 58.0805 degrees C, with an estimated uncertainty of +/- 0.0015 degrees C relative to the International Practical Temperature Scale of 1968 (IPTS-68). The triple-point temperature of this material is evaluated as a temperature-fixed point, and some clinical laboratory applications of this fixed point are proposed. In conjunction with the gallium and ice points, the availability of succinonitrile permits thermistor thermometers to be calibrated accurately and easily on the IPTS-68.

The Gallium Melting-Point Standard: A Determination of the Liquid—Solid Equilibrium Temperature of Pure Gallium on the International Practical Temperature Scale of 1968

1977 ◽  
Vol 23 (4) ◽  
pp. 719-724 ◽  
Author(s):  
Donald D Thornton
Keyword(s):  
Melting Point ◽  
Melting Temperature ◽  
Temperature Scale ◽  
Equilibrium Temperature ◽  
Melting Range ◽  
Practical Temperature ◽  
Practical Temperature Scale ◽  
Gallium Melting Point

Abstract The sharpness and reproducibility of the gallium melting point were studied, and the melting temperature of gallium in terms of IPTS-68 was determined. Small melting-point cells designed for use with thermistors are described. Nine gallium cells including three levels of purity were used in 68 separate determinations of the melting point. The melting point of 99.99999% pure gallium in terms of IPTS-68 is found to be 29.7714 ± 0.0014 °C; the melting range is less than 0.0005 °C and is reproducible to ±0.0004 °C.

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