HIGH TEMPERATURE CALORIMETRY: I. A NEW ADIABATIC CALORIMETER

1950 ◽  
Vol 28a (1) ◽  
pp. 44-50 ◽  
Author(s):  
L. D. Armstrong
Keyword(s):  
High Temperature ◽  
Specific Heat ◽  
Temperature Interval ◽  
High Temperatures ◽  
Adiabatic Calorimeter ◽  
Small Temperature ◽  
Specific Heats ◽  
Definite Temperature

In this paper is described a new calorimeter for the measurement of specific heats at high temperatures, by the adiabatic method. The advantage is that the specific heat at a definite temperature can be determined by a measurement taken over a small temperature interval, with a precision of 1% or better, throughout the range 400 °C. to 800 °C. This permits a study of specific heat anomalies in this range.

scholarly journals On the velocity of sound in gases at high temperatures, and the ratio of the specific heats

1921 ◽  
Vol 100 (702) ◽  
pp. 1-26 ◽  
Keyword(s):  
Specific Heat ◽  
High Temperatures ◽  
Velocity Of Sound ◽  
Specific Heats ◽  
A Value ◽  
Mean Temperature ◽  
Considerable Experience

The experiments described in this memoir on the velocity of sound in gases, at temperatures varying from atmospheric to that of a bright red heat, were made with the object of tracing the change in the specific heat of gases with rising temperature, and, if possible, of arriving at formulæ which might be applicable to the extremely high temperatures reached in explosions. The sound method was decided on chiefly for the reasons (1) that the velocity of sound in a heated gas gives a value for the ratio of the two specific heats at the temperature of the experiment, and not as in the method of mixtures at a mean temperature between the highest and lowest point of the heated and cooled gas; and (2) because we had had considerable experience in the use of a chronograph for measuring the rapid movements of flame through gases in long tubes. It is necessary to make it clear at starting that no claim is made that these experiments give more exact determinations of the specific heat of gases than those given previously by experiments over low ranges of temperature; the object has been to obtain by comparative measurements the general gradients of the curves rather than to find the exact value at any definite point.

Thermal Properties of Alcaline-Earth-Oxides I. Specific heat measurements 1-3 Centre National de Recherches sur les Tres Basses Temperatures

1969 ◽  
Vol 24 (11) ◽  
pp. 1794-1800 ◽  
Author(s):  
E. Gmelin
Keyword(s):  
Thermal Properties ◽  
Specific Heat ◽  
Adiabatic Calorimeter ◽  
Heat Capacities ◽  
Temperature Calibration ◽  
Specific Heats ◽  
Thermal Switch ◽  
Heat Capacities Of Solids ◽  
Better Than

Abstract The heat capacities of MgO, CaO, SrO, BaO, having NaCl-structure, have been measured with an adiabatic calorimeter capable to measure heat capacities of solids between 1.2 and 340 °K. A mechanical thermal switch is used for specimen cooling and the temperature calibration above 4 °K is performed with a gas thermometer. The values of the specific heats, Cv , are tabulated. The entropies at 273.15 °K are 27.19; 38.3; 51.9; and 66.9 for MgO. CaO, SrO and BaO respectively, in J/mol °K. The accuracy of the measurements is estimated to be better than 0.8% (smoothed curve).

The contribution of electronic excitation to the total specific heats of high temperature gases: a misinterpreted absence

1971 ◽  
Vol 5 (1) ◽  
pp. 115-121 ◽  
Author(s):  
M. Capitelli ◽  
E. Ficocelli
Keyword(s):  
High Temperature ◽  
Specific Heat ◽  
Electronic Excitation ◽  
Electronic Contribution ◽  
Specific Heats

It is shown that the reported absence of a contribution of electronic excitation on to the total specific heats of helium and nitrogen (10,000–35,000°K, 10−1−10 atm) should be attributed to the presence of compensation effects among the various terms into which the total specific heat can be separated and that these terms are influenced by the electronic contribution.

q-Deformed Tamm–Dancoff oscillators: Coherent state and thermostatistics

2014 ◽  
Vol 28 (21) ◽  
pp. 1450130 ◽  
Author(s):  
Won Sang Chung ◽  
Abdullah Algin
Keyword(s):  
High Temperature ◽  
Equation Of State ◽  
Coherent State ◽  
Specific Heat ◽  
High Temperatures ◽  
Deformation Parameter ◽  
Quantum Systems ◽  
Oscillator Algebra ◽  
Many Body ◽  
The Real

The q-deformed bosonic Tamm–Dancoff oscillator algebra is considered. The coherent state of the q-deformed bosonic Tamm–Dancoff oscillator algebra is first constructed in detail. Second, the high-temperature thermostatistical properties of a gas of the Tamm–Dancoff oscillators are investigated. For high temperatures, the specific heat, the entropy and the equation of state for the system are derived in terms of the real deformation parameter q. The results obtained by the effects of Tamm–Dancoff type q-deformation show that they could be useful for further researches on understanding of mutual interactions between bosons and fermions in many-body quantum systems.

scholarly journals High-temperature Thermodynamics of the Hubbard Model

1993 ◽  
Vol 46 (5) ◽  
pp. 613
Author(s):  
J Oitmaa ◽  
JA Henderson
Keyword(s):  
High Temperature ◽  
Hubbard Model ◽  
Specific Heat ◽  
High Temperatures ◽  
Padé Approximants ◽  
Numerical Results ◽  
Strongly Correlated ◽  
Cubic Lattices ◽  
Simple Cubic ◽  
Atomic Limit

Recently derived 10th-order high-temperature expansions for the Hubbard model are used to obtain the ferromagnetic susceptibility and specific heat at high temperatures. Numerical results are obtained for the simple cubic and face-centred cubic lattices by using Pade approximants to sum the series. The results are compared with two solvable limiting cases, namely the non-interacting limit U = 0 and the strongly-correlated or atomic limit t = O.

scholarly journals The specific heat of gases at high temperatures

1939 ◽  
Vol 238 (789) ◽  
pp. 149-228 ◽  
Keyword(s):  
Specific Heat ◽  
High Temperatures ◽  
Combustion Engine ◽  
National Physical Laboratory ◽  
Closed Vessel ◽  
Gaseous Mixtures ◽  
Specific Heats ◽  
Physical Laboratory ◽  
Engineering Department ◽  
Band Spectra

For many years work has been in progress in the Engineering Department of the National Physical Laboratory on problems involving the explosion of gaseous mixtures in a closed vessel or bomb (Fenning 1924, 1925, 1926; Fenning and Tizard 1927). The experience gained and the technique developed were considered to warrant a new attack being made on the measurement of the specific heats of gases at high temperatures, particularly of those gases which comprise the working substance of the internal combustion engine. The work was therefore put in hand and carried out for the Department of Scientific and Industrial Research. At the time the investigation was started a considerable amount of data, based on explosion experiments, was available, and this was being supplemented by values of the specific heat obtained from the analysis of the band spectra of the gases concerned. Activity in this latter field has continued and values are now available for a considerable number of gases over a wide temperature range as will be seen from a summary by Lewis and von Elbe (1935 a ) published about three years ago.

HIGH TEMPERATURE CALORIMETRY: II. ATOMIC HEATS OF CHROMIUM, MANGANESE, AND COBALT BETWEEN 0° AND 800 °C.

1950 ◽  
Vol 28a (1) ◽  
pp. 51-59 ◽  
Author(s):  
L. D. Armstrong ◽  
H. Grayson-Smith
Keyword(s):  
High Temperature ◽  
Specific Heat ◽  
Crystal Form ◽  
Gradual Transition ◽  
Additional Source ◽  
Conduction Electrons ◽  
Specific Heats ◽  
Reverse Transition ◽  
Antiferromagnetic Transitions ◽  
Cobalt And Nickel

The atomic heats of chromium, manganese, and cobalt have been measured up to 800 °C. by the adiabatic method described in Part I of this series. The specific heat of chromium is regular from 0° to 800 °C. The measurements with manganese show the sharp α−β transition at 717 °C., with a latent heat of 450 cal. per mole. Typical supercooling occurs on the reverse transition. Cobalt shows an anomaly due to a gradual transition, which is known to be a change in crystal form. The new data obtained permit a comparative discussion of the atomic heats of the transition metals, chromium to nickel. All these have values Cv > 3R at high temperatures. After allowing for the effects of ferromagnetism, the excess specific heats of cobalt and nickel are accounted for by the conduction electrons. This is not true for chromium and manganese, for which metals there must be some additional source of internal energy. It is tentatively suggested that these two metals may have antiferromagnetic transitions at temperatures above 800 °C.

scholarly journals The determination of the specific heat of gases at high temperatures by the sound velocity method I―Carbon monoxide

1934 ◽  
Vol 147 (861) ◽  
pp. 292-308 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Specific Heat ◽  
Sound Velocity ◽  
High Temperatures ◽  
Transient Phenomena ◽  
Radiation Correction ◽  
Specific Heats ◽  
Explosion Method

The determination of the specific heats of gases at high temperatures is a problem of unusual difficulty and the attempts hitherto made to measure specific heats at temperatures exceeding 1200° C have been by the "explosion method." This method involves the observation of transient phenomena and also the estimation of a relatively large radiation correction.

ON THE SPECIFIC HEATS OF TUNGSTEN, MOLYBDENUM, AND COPPER

1933 ◽  
Vol 8 (3) ◽  
pp. 282-303 ◽  
Author(s):  
H. L. Bronson ◽  
H. M. Chisholm ◽  
S. M. Dockerty
Keyword(s):  
Specific Heat ◽  
Linear Equations ◽  
Adiabatic Calorimeter ◽  
Absolute Temperature ◽  
Large Temperature ◽  
Average Deviation ◽  
Specific Heats ◽  
New Type ◽  
The Individual ◽  
Theoretical Considerations

This paper contains the results of a long series of determinations of the specific heats of tungsten, molybdenum, and copper from − 20° to 500 °C.A new type of all-copper adiabatic calorimeter has been designed and used. The complete elimination of water from the calorimeter removed several sources of error and resulted in increased reliability and accuracy.Two entirely different methods were used in determining the specific heats. The usual "method of mixtures" was used to determine the mean specific heat for a large temperature change and was applied to all three metals over the entire range of temperature. The specific heat of copper was also determined for 5- or 10-degree intervals from − 5° to 110 °C. by heating the calorimeter electrically.It has been quite definitely shown that the specific heats of these metals over a temperature range as large as 0° to 500 °C. cannot be expressed as a linear function of the temperature. An equation of the form Cp = A + BT − C/T2 was arrived at from theoretical considerations and the constants determined empirically with the following results:—[Formula: see text]where the unit of heat is the 20-degree calorie and T is absolute temperature. The average deviation of the individual determinations from the values calculated by these equations was only about 0.1%.As a matter of convenience and for purposes of comparison, linear equations applicable over smaller ranges of temperature have also been given.

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