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 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.

The Gallium Melting-Point Standard: Its Role in Our Temperature Measurement System

1977 ◽  
Vol 23 (4) ◽  
pp. 711-718 ◽  
Author(s):  
B W Mangum
Keyword(s):  
Melting Point ◽  
Temperature Scale ◽  
Medical Professional ◽  
National Bureau ◽  
Voluntary Standards ◽  
Temperature Reference ◽  
Practical Temperature ◽  
Clinical Enzymology ◽  
Temperature Measurement System ◽  
Gallium Melting Point

Abstract The latest internationally-adopted temperature scale, the International Practical Temperature Scale of 1968 (amended edition of 1975), is discussed in some detail and a brief description is given of its evolution. The melting point of high-purity gallium (stated to be at least 99.99999 % pure) as a secondary temperature reference point is evaluated. I believe that this melting-point tem-perature of gallium should be adopted by the various medical professional societies and voluntary standards groups as the reaction temperature for enzyme reference methods in clinical enzymology. Gallium melting-point cells are available at the National Bureau of Standards as Standard Reference Material No. 1968.

Calorimetric determination of the deviation between the International Practical Temperature Scale 1968 and the Thermodynamic Temperature Scale

1988 ◽  
Vol 66 (4) ◽  
pp. 999-1004 ◽  
Author(s):  
Günter Ernst ◽  
Günter Bräuning ◽  
Joon-Fen Lai
Keyword(s):  
Temperature Scale ◽  
Thermodynamic Temperature ◽  
Triple Point Of Water ◽  
Flow Calorimeter ◽  
Practical Temperature ◽  
Practical Temperature Scale ◽  
Calorimetric Determination ◽  
Thermodynamic Temperature Scale ◽  
Good Agreement

A flow calorimeter was constructed to measure the isobaric heat capacity cp for dilute fluids for pressure [Formula: see text] and for temperature [Formula: see text]. The special design features of the calorimeter facilitate measurements at extremely high accuracy. In this paper the measurements have been used to explore the metrology of the temperature. Measured values of cp were compared with corresponding theoretical values calculated via statistical mechanics. From the comparison, the deviation between the International Practical Temperature Scale of 1968 and the (theoretical) Thermodynamic Temperature Scale has been obtained. The results of this metrology are in good agreement with those obtained with the PVT gas thermometer and those obtained by radiometry. The comparison establishes the accuracy of the calorimeter and, more important, the feasibility of cp metrology, especially for probing local stretching or contraction of the International Practical Temperature Scale. The integration of this distortion, starting from the triple point of water, yields the deviation between the scales. It is, e.g., between 30 mK and 40 mK at the boiling point of water, according to our results.

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.

Sign in / Sign up

Export Citation Format

Share Document