AN ADIABATIC CALORIMETER FOR THE TEMPERATURE REGION BELOW 20°K.—THE SPECIFIC HEAT OF SODIUM CHLORIDE

1955 ◽  
Vol 33 (2) ◽  
pp. 375-382 ◽  
Author(s):  
J. A. Morrison ◽  
D. Patterson ◽  
J. S. Dugdale
Keyword(s):  
Sodium Chloride ◽  
Specific Heat ◽  
Temperature Region ◽  
Low Temperatures ◽  
Characteristic Temperature ◽  
Expansion Method ◽  
Adiabatic Calorimeter ◽  
Helium Gas ◽  
Carbon Resistor ◽  
Made In

A simple adiabatic calorimeter for specific heat measurements at very low temperatures is described. Liquid helium is made in the cryostat by the Simon expansion method. The calorimeter and adiabatic shield are cooled below 13°K. by conduction of heat along the lead wires rather than by conduction with exchange gas. The working thermometer is a carbon resistor which has been calibrated against a helium gas thermometer. The assembly has been used to determine the specific heat of rock salt between 2.5° and 20°K. The results are compared with the theoretically derived values of the specific heat and Debye characteristic temperature for sodium chloride.

The thermal conductivities of some dielectric solids at low temperatures (Experimental)

1951 ◽  
Vol 208 (1092) ◽  
pp. 90-108 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Specific Heat ◽  
Temperature Variation ◽  
Temperature Region ◽  
Low Temperatures ◽  
Quartz Crystal ◽  
Corundum Crystal ◽  
Before And After ◽  
Dielectric Solids

An apparatus is described in which the thermal conductivity of solids can be determined at any temperature between 2 and 90°K. Several glasses and dielectric crystals have been measured. It had previously been found that at high temperatures the conductivity of glasses is proportional to the specific heat, but at low temperatures it falls off more slowly than the specific heat. The present experiments show that there is a temperature region in which the conductivity is nearly independent of temperature. A similar variation of conductivity is found for the thermo-plastic Perspex. The effect of lattice defects in crystals was studied by measuring the thermal conductivity of a quartz crystal before and after successive periods of neutron irradiation. After prolonged irradiation the conductivity approached, in both magnitude and temperature variation, that of quartz glass. Subsequent heating produced a substantial recovery in the conductivity. The results on both glasses and on crystals can be explained by the theory developed by Klemens (1951). Further measurements made on a corundum crystal confirm the importance of the ‘Umklapp’ processes, postulated by Peierls, in causing thermal resistance.

scholarly journals 2. On the Computation of the Specific Heat of Liquid Water, at various Temperatures, from the experiments of M. Regnault.

1857 ◽  
Vol 3 ◽  
pp. 90
Author(s):  
W. J. Macquorn Rankine
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Specific Heat ◽  
Liquid Water ◽  
Low Temperatures ◽  
Fluid Friction ◽  
Made In

The experiments of M. Regnault having been made by introducing water at a high temperature from a boiler into a calorimeter, containing water at a low temperature, and power exercised by the steam in the boiler in expelling the water was converted into heat by fluid friction, thus producing a rise of temperature in the calorimeter, for which allowance ought to be made in calculating the specific heat of liquid water from each experiment. Mr Joule's determination of the dynamical value of the specific heat of liquid water at low temperatures affords the means of calculating the correction required in each case.

SPIN FLUCTUATIONS IN TCo2 STUDIED BY RESISTIVITY AND THERMOPOWER EXPERIMENTS (T = Y, Lu, Sc, Hf, Zr, Ce)

1993 ◽  
Vol 07 (01n03) ◽  
pp. 370-373 ◽  
Author(s):  
N. BARANOV ◽  
E. BAUER ◽  
E. GRATZ ◽  
R. HAUSER ◽  
A. MARKOSYAN ◽  
...  
Keyword(s):  
Low Temperature ◽  
Specific Heat ◽  
Temperature Dependence ◽  
Temperature Region ◽  
Low Temperatures ◽  
Spin Fluctuations ◽  
General Tendency ◽  
Electronic Specific Heat ◽  
Temperature Dependent

The temperature dependence of the resistivity and the thermopower in the region from 4.2K up to 1000K for the six isostructural paramagnetic compounds TCo 2 (T=Y, Lu, Sc, Hf, Zr, Ce) is studied. The resistivity ρ (T) follows a T 2 dependence at low temperatures in all these compounds. Plotting the A values into an A vs. γ2 diagram shows that YCo 2, LuCo 2, and ScCo 2 are spinfluctuation systems (A and γ denote the coefficients in ρ (T) = ρ0 + AT 2 and that of the electronic specific heat, respectively) HfCo 2 and ZrCo 2 do not fit into this general tendency in the ( A , γ2)-diagram. The temperature dependent thermopower S(T) in YCo 2, LuCo 2 and ScCo 2 exhibits a pronounced minimum in the low temperature region. These minima are obviously connected with the existence of spin fluctuations (paramagnon-drag). Spin fluctuations in HfCo 2 and ZrCo 2 are less important. This we conclude also from the ten times smaller A-values and the missing minimum in the thermopower at low temperatures.

The thermal properties of alkali halide crystals. I. The heat capacity of potassium chloride, potassium bromide, potassium iodide and sodium iodide between 2.8 and 270˚K

1957 ◽  
Vol 242 (1231) ◽  
pp. 467-477 ◽  
Keyword(s):  
Sodium Iodide ◽  
Platinum Resistance Thermometer ◽  
Adiabatic Calorimeter ◽  
Platinum Resistance ◽  
Potassium Salts ◽  
Resistance Thermometer ◽  
Helium Gas ◽  
Alkali Halide Crystals ◽  
Carbon Resistor ◽  
Better Than

The measurements were made with two adiabatic calorimeter assemblies, one for the temperature range 2.8 to 20°K and the other for the range 12 to 270°K. The working thermometer for the former assembly was a carbon resistor and for the latter a strain-free capsule-type platinum resistance thermometer. The crystals (pieces approximately 0.5 cm in dimension) were sealed in thin copper calorimeter vessels with a small amount of helium gas to promote heat exchange. The accuracy of the measurements is estimated to be ± 2% at the lowest temperatures, rising rapidly to ± 0.2% for T ⋝ 20°K. The precision was generally better than this by about a factor of two at most temperatures. Apparent Debye characteristic temperatures (Θ D ) have been calculated for all of the experi­mental results. The variation of Θ D with temperature is in general accord with the predictions of theory. Starting from the lowest temperatures, Θ D for the three potassium salts first decreases to a minimum in the region of T = Θ D /12, then increases to a maximum in the region of T = Θ D /2 and subsequently decreases smoothly. Θ D for sodium iodide shows the same behaviour at low temperatures but is still increasing at 270° K.

Specific heat of ordered and isotopically disordered lattices

1978 ◽  
Vol 56 (10) ◽  
pp. 1390-1394
Author(s):  
K. P. Srivastava
Keyword(s):  
Specific Heat ◽  
Low Temperatures ◽  
Numerical Study ◽  
Three Dimensional ◽  
Constant Volume ◽  
Nearest Neighbour ◽  
Two Dimensional ◽  
Appreciable Difference ◽  
Substantial Change ◽  
Neighbour Interaction

An extensive numerical study on specific heat at constant volume (Cv) for ordered and isotopically disordered lattices has been made. Cv at various temperatures for ordered and disordered linear and two-dimensional lattices have been compared and no appreciable difference in Cv between these two structures has been observed. Effect of concentration of light atoms on Cv for three-dimensional isotopically disordered lattices has also been shown.In spite of taking next-nearest-neighbour interaction into account, no substantial change in Cv between the ordered and isotopically disordered linear lattices has been found. It is shown that the low lying modes contribute substantially at low temperatures.

Specific heat of the iron-hydrogen system at low temperatures

1979 ◽  
Vol 13 (7) ◽  
pp. 573-575 ◽  
Author(s):  
Hiroaki Wada ◽  
Koshiro Sakamoto
Keyword(s):  
Specific Heat ◽  
Low Temperatures ◽  
Hydrogen System

New reaction for recognition of pregnancy and gender of the intrauterine fetus

1926 ◽  
Vol 22 (1) ◽  
pp. 106
Author(s):  
V. Gruzdev
Keyword(s):  
Sodium Chloride ◽  
Blood Serum ◽  
Test Tube ◽  
And Gender ◽  
Made In

Sellheim (Zentr. F. Gyn., 1925, no. 32) the trace describes this reaction, which he calls the Lttge-Mertz-Berger reaction: 1 cubic meter is poured into a test tube. sant. the blood serum of a woman in whom pregnancy is suspected, or the sex of the fetus of which they want to find out, then add here a certain amount (the amount of this S. does not indicate) extracts from the placenta or testicles, mixed with a solution of sodium chloride (in what proportion - S. also does not indicates, but only says that this extract can be obtained ready-made, in ampoules, from the Wolff company in Bielefeld).

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