A STUDY OF THE COEXISTENCE OF THE LIQUID AND GASEOUS STATES OF AGGREGATION IN THE CRITICAL TEMPERATURE REGION. ETHANE

1940 ◽  
Vol 18b (4) ◽  
pp. 103-117 ◽  
Author(s):  
S. G. Mason ◽  
S. N. Naldrett ◽  
O. Maass
Keyword(s):  
Critical Temperature ◽  
Temperature Region ◽  
Coexistence Curve ◽  
Absolute Temperature ◽  
Temperature Measurements ◽  
Careful Study ◽  
Physical Measurement ◽  
Relative Temperature ◽  
Density Measurements ◽  
Parabolic Shape

A careful study has been made of the position and nature of the meniscus and the distribution of opalescence in bombs containing ethane as the critical temperature is approached. Photographs of the phenomena have been made. The effect of shaking has been observed, and a type of shaking is described that is believed to hasten the attainment of equilibrium between the liquid and vapour phases. Using this type of stirring the coexistence curve of ethane has been determined. Relative temperature measurements are accurate to within ± 0.001 ° C.; absolute temperature measurements, to within ± 0.015 °C. Density measurements are believed accurate to within 1:3000. The limiting curve has the classical parabolic shape up to 32.23 °C., at which point the slope changes abruptly and the curve becomes flat along the density axis. The authors believe that at this temperature a dispersion of liquid and vapour occurs and that liquid still persists above this temperature. It is shown that the critical temperature as ordinarily determined in a stationary bomb cannot be accurately determined. The critical temperature can be determined precisely and without ambiguity when the bomb is shaken, and it is recommended that the value obtained in this way be used instead, as a physical measurement.

A STUDY OF THE COEXISTENCE OF THE LIQUID AND GASEOUS STATES OF AGGREGATION IN THE CRITICAL TEMPERATURE REGION. ETHYLENE

1940 ◽  
Vol 18b (4) ◽  
pp. 118-121 ◽  
Author(s):  
S. N. Naldrett ◽  
O. Maass
Keyword(s):  
Critical Temperature ◽  
Temperature Region ◽  
Previous Investigation ◽  
Coexistence Curve

The coexistence curve of ethylene has been determined in a manner similar to that described in a previous investigation on ethane (9). It is found to lie entirely within the coexistence curve determined by P-V-T methods by other investigators (6). This is considered to be evidence for the formation of a dispersion of liquid and vapour before the critical temperature is reached. The term "critical dispersion temperature" is suggested for the temperature at the apex of the coexistence curve determined by the disappearance of the meniscus in a bomb shaken in the manner described in this investigation. The apex of the curve determined by P-V-T methods is the true critical temperature, beyond which liquid is not stable. The classical critical temperature, determined by the disappearance of the meniscus in a stationary bomb, is an indefinite point between these two.

Critical constants and density dependence of the Lorenz–Lorentz coefficient for germane

1978 ◽  
Vol 56 (9) ◽  
pp. 1140-1141 ◽  
Author(s):  
P. Palffy-Muhoray ◽  
D. Balzarini
Keyword(s):  
Critical Temperature ◽  
Density Dependence ◽  
Experimental Error ◽  
Critical Density ◽  
Coexistence Curve ◽  
Index Of Refraction ◽  
Density Range ◽  
Temperature Range ◽  
Critical Constants

The index of refraction at 6328 Å has been measured for germane in the density range 0.15 to 0.9 g/cm3. The temperature and density ranges over which measurements are made are near the coexistence curve. The coefficient in the Lorenz–Lorentz expression, [Formula: see text], is constant to within 0.5% within experimental error for the temperature range and density range studied. The coefficient is slightly higher near the critical density. The critical density is measured to be 0.503 g/cm3. The critical temperature is measured to be 38.92 °C.

scholarly journals Multinuclear absolute magnetic resonance thermometry

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Emilia V. Silletta ◽  
Alexej Jerschow ◽  
Guillaume Madelin ◽  
Leeor Alon
Keyword(s):  
Magnetic Resonance ◽  
Ex Vivo ◽  
Absolute Temperature ◽  
Main Magnetic Field ◽  
Relative Temperature ◽  
Temperature Changes ◽  
Non Invasive ◽  
Mouse Tissues ◽  
Infrared Measurements

AbstractNon-invasive measurement of absolute temperature is important for proper characterization of various pathologies and for evaluation of thermal dose during interventional procedures. The proton (hydrogen nucleus) magnetic resonance (MR) frequency shift method can be used to map relative temperature changes. However, spatiotemporal variations in the main magnetic field and the lack of local internal frequency reference challenge the determination of absolute temperature. Here, we introduce a multinuclear method for absolute MR thermometry, based on the fact that the hydrogen and sodium nuclei exhibit a unique and distinct characteristic frequency dependence with temperature and with electrolyte concentration. A one-to-one mapping between the precession frequency difference of the two nuclei and absolute temperature is demonstrated. Proof-of-concept experiments were conducted in aqueous solutions with different NaCl concentrations, in agarose gel samples, and in freshly excised ex vivo mouse tissues. One-dimensional chemical shift imaging experiments also demonstrated excellent agreement with infrared measurements.

On the NaCl-H2O coexistence curve near the critical temperature of H2O

1989 ◽  
Vol 156 (4) ◽  
pp. 415-417 ◽  
Author(s):  
A.H. Harvey ◽  
J.M.H.Levelt Sengers
Keyword(s):  
Critical Temperature ◽  
Coexistence Curve

SOLUBILITY MEASUREMENTS IN THE REGION OF THE CRITICAL TEMPERATURE

1940 ◽  
Vol 18b (9) ◽  
pp. 293-304 ◽  
Author(s):  
C. H. Holder ◽  
O. Maass
Keyword(s):  
Critical Temperature ◽  
Temperature Region ◽  
Pressure Change ◽  
Liquid Phases

An apparatus for the measurement of solubility in the critical temperature region has been constructed. This apparatus permits samples to be taken from the upper and lower regions (vapour and liquid phases, if below critical temperature) of a system without volume or pressure change so that equilibrium is not disturbed.Solubility measurements of hexachloroethane in ethane have been made through the critical temperature region.

THE POLARIZATION OF LIQUIDS AND THEIR SATURATED VAPORS IN THE CRITICAL TEMPERATURE REGION

1936 ◽  
Vol 14b (3) ◽  
pp. 90-95
Author(s):  
J. Marsden ◽  
O. Maass
Keyword(s):  
Critical Temperature ◽  
Methyl Ether ◽  
Temperature Region ◽  
Room Temperature ◽  
Saturated Vapor ◽  
Dielectric Constants

The values of the so-called polarization of methyl ether (liquid and saturated vapor) and propylene (liquid and saturated vapor), from room temperature to the critical temperature, are given. In both liquids this polarization is independent of the temperature to within a few degrees of the critical temperature. Calculations show that the polarizations of a liquid and its saturated vapor may be equal above the critical temperature, even though the dielectric constants of the liquid and its saturated vapor, as well as their densities, are different.

Effect of pseudogap on the specific heat of superconductor

2015 ◽  
Vol 29 (24) ◽  
pp. 1550180 ◽  
Author(s):  
Thaipanya Chanpoom
Keyword(s):  
Critical Temperature ◽  
Specific Heat ◽  
Temperature Region ◽  
Analytic Form ◽  
Superconducting Gap ◽  
Crossover Temperature ◽  
Specific Heat Jump

In this paper, the superconductor with the competition of superconducting gap and pseudogap in the below crossover temperature region is calculated. The superconducting gap and pseudogap is assumed to arise from independent and competing correlation. The critical temperature, superconducting gap and the specific heat jump are derived in the analytic form and the approximation is used to simplify the equations obtained for the region that crossover temperature and energy of pseudogap are higher than critical temperature. We find that the critical temperature is decreased as the energy of pseudogap and crossover temperature as increased. The superconductor with pseudogap has small specific heat jump in comparison with the BCS value. Increasing the crossover temperature and critical temperature, the specific heat jump is decreased.

ON THE LIQUID–VAPOR COEXISTENCE CURVE OF XENON IN THE REGION OF THE CRITICAL TEMPERATURE

1952 ◽  
Vol 30 (5) ◽  
pp. 422-437 ◽  
Author(s):  
M. A. Weinberger ◽  
W. G. Schneider
Keyword(s):  
Critical Temperature ◽  
Critical Region ◽  
Van Der Waals ◽  
Coexistence Curve ◽  
Packing Materials ◽  
Critical Data ◽  
Van Der Waals Theory ◽  
Liquid Vapor

The liquid–vapor coexistence curves of very pure xenon have been determined in bombs of vertical lengths 1.2 cm. and 19 cm. The longer bomb yielded a flat-topped coexistence curve, the shorter a more rounded curve. The classical van der Waals theory is capable of explaining a large portion of the flat top if effects of gravity are taken into account. Details of the theoretical variation of the width of the flat top with vertical bomb lengths are given. The critical data obtained for xenon are ρc = 1.105 gm./cc., Tc = 16.590 ±.001 °C. The danger of contamination of gases in the critical region on contact with gasket or packing materials is stressed.

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