RADIATION EFFECTS IN PRECISION RESISTANCE THERMOMETRY: I. RADIATION LOSSES IN TRANSPARENT THERMOMETER SHEATHS

1966 ◽  
Vol 44 (11) ◽  
pp. 2631-2652 ◽  
Author(s):  
E. H. McLaren ◽  
E. G. Murdock
Keyword(s):  
Radiation Effects ◽  
Near Infrared ◽  
Platinum Resistance Thermometer ◽  
Fused Silica ◽  
Platinum Resistance ◽  
Resistance Thermometer ◽  
Fixed Temperature ◽  
Radiation Losses ◽  
Platinum Resistance Thermometers ◽  
Resistance Thermometers

Standard platinum resistance thermometers that are constructed with transparent sheaths of fused silica or pyrex glass are subject to thermal losses arising from losses of visible and near-infrared radiation up (piping) and through these sheaths. This heat loss may introduce substantial errors in temperature determinations; e.g. 0.084, 0.015, and 0.001 1 °C at the Sb, Zn, and Sn fixed-temperature points for a fused-silica sheath, or 0.000 2 °C at the Zn and Sn points for a pyrex sheath. This effect has been investigated in detail for thermometers of various types at the Sb, Zn, and Sn points, and it has been shown that simple stem radiation-traps, consisting of a blackening or roughening of the smooth outer surface of the thermometer sheaths, will eliminate these errors and greatly improve the immersion characteristics of the thermometers.Suitable radiation-trapping should be incorporated on the stems of every transparent-sheathed standard platinum resistance thermometer; without strong evidence to the contrary, radiation loss errors of the orders of magnitude cited above should be suspected in reported measurements involving resistance thermometers having unprotected transparent fused-silica sheaths.

A MODIFIED CONTINUOUS-HEATING CALORIMETER FOR THE TEMPERATURE RANGE 15° TO 300° K

1962 ◽  
Vol 40 (9) ◽  
pp. 1166-1173 ◽  
Author(s):  
Douglas L. Martin
Keyword(s):  
Temperature Region ◽  
Room Temperature ◽  
Platinum Resistance Thermometer ◽  
Continuous Heating ◽  
Platinum Resistance ◽  
Resistance Thermometer ◽  
Platinum Resistance Thermometers ◽  
Resistance Thermometers ◽  
New Apparatus ◽  
Cold Worked

The calorimeter described by Martin in 1960 has been modified to permit the use of a platinum resistance thermometer and to enable measurements to be made on granular or powdered samples. Measurements in the room temperature region on the Calorimetry Conference Standard Sample of aluminum oxide show this new apparatus to have an accuracy of the order of 0.1%. Annealed and cold-worked copper samples measured previously have been remeasured from 15° to 90° K and in the room temperature region. A previously measured lithium sample has been remeasured between 100° and 300° K. Excellent agreement between the earlier and present sets of results confirms the accuracy of much previous work from this laboratory. The comparative usefulness of copper and platinum resistance thermometers in calorimetry is discussed.

I. On a determination of the boiling point of sulphur, and on a method of standardising platinum resistance thermometers by reference to it

1891 ◽  
Vol 49 (296-301) ◽  
pp. 56-60
Keyword(s):  
Accurate Method ◽  
Platinum Resistance Thermometer ◽  
Platinum Resistance ◽  
Resistance Thermometer ◽  
Platinum Resistance Thermometers ◽  
Resistance Thermometers ◽  
Wide Range ◽  
The Difference ◽  
Relative Measurements

Experiments by different observers have shown that electrical resistance thermometers afford the most convenient and accurate method of measuring temperature through a very wide range. By selecting a particular thermometer as the standard, and directly comparing others with it, it has been found possible to attain a degree of accuracy of the order of 0°·001 in the relative measurements between 0° and 100°C., and of the order of 0º·01 at 450°C. In a previous communication* it has been shown that, if t be the temperature by air thermometer, and if pt be the temperature by platinum resistance thermometer, the difference between them is very closely represented from 0° to 700°C. by the formula d = t - pt = δ { t /100│ 2 — - t /100} ... ( d ).

RADIATION EFFECTS IN PRECISION RESISTANCE THERMOMETRY: II. ILLUMINATION EFFECT ON TEMPERATURE MEASUREMENT IN WATER TRIPLE-POINT CELLS PACKED IN CRUSHED ICE

1966 ◽  
Vol 44 (11) ◽  
pp. 2653-2659 ◽  
Author(s):  
E. H. McLaren ◽  
E. G. Murdock
Keyword(s):  
Triple Point ◽  
Radiation Effects ◽  
Near Infrared ◽  
Radiation Shielding ◽  
Platinum Resistance ◽  
Platinum Resistance Thermometers ◽  
Resistance Thermometers ◽  
Temperature Errors ◽  
Crushed Ice ◽  
Water Triple Point

The heating effect of normal laboratory illumination on the sensors of standard platinum resistance thermometers immersed in a standard water triple-point cell packed in crushed ice has been investigated. This study shows that the absorption by the platinum sensors of luminous and near-infrared radiation transmitted through the ice pack could easily amount to temperature errors as large as 0.000 5 °C. Any illumination error must be eliminated by making all measurements in the dark or under adequate radiation shielding.

HYDROGEN PEROXIDE AND ITS ANALOGUES: II. PHASE EQUILIBRIUM IN THE SYSTEM HYDROGEN PEROXIDE – WATER

1951 ◽  
Vol 29 (2) ◽  
pp. 123-132 ◽  
Author(s):  
William T. Foley ◽  
Paul A. Giguère
Keyword(s):  
Hydrogen Peroxide ◽  
Phase Equilibrium ◽  
Solid Solutions ◽  
Freezing Point ◽  
Platinum Resistance Thermometer ◽  
Platinum Resistance ◽  
Radioactive Tracers ◽  
Resistance Thermometer ◽  
Pure Solution

A precision freezing point apparatus with platinum resistance thermometer was used to investigate the system hydrogen peroxide – water over the whole concentration range. The freezing point of the purest sample of hydrogen peroxide obtained by repeated fractional crystallizations of a large quantity of 99.6% pure solution was found to be −0.461°C; that of the dihydrate was −52.10°C. The two eutectics occur at concentrations of 45.2% and 61.2% H2O2 and at temperatures of −52.4° and −56.5°C. respectively. Contrary to what has been reported previously, water and hydrogen peroxide do not form solid solutions together. This was proved conclusively by applying the technique of radioactive tracers to the 'wet residue' method of Schreinemakers.

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