JAMES DEWAR. - On the boiling point of liquid hydrogèn under reduced pressure (Sur le point d'ébullition de l'hydrogène aux faibles pressions). - Proc. of the Royal Soc., t. LXIV, p. 227; 15 décembre 1898.—Application of liquid hydrogen to the production of high vacua, together with their spectroscopic examination (Application de l'hydrogène liquide à la production de vides avancés; examen au spectroscope). - Id., p. 231

1899 ◽  
Vol 8 (1) ◽  
pp. 611-613
Author(s):  
Ch. Maurain
Keyword(s):  
Boiling Point ◽  
Liquid Hydrogen ◽  
Reduced Pressure ◽  
Spectroscopic Examination ◽  
James Dewar

scholarly journals Papers read to the Society, December 15, 1898

1899 ◽  
Vol 64 (402-411) ◽  
pp. 171-171
Keyword(s):  
Nervous System ◽  
Electrical Discharge ◽  
Liquid Hydrogen ◽  
Atmospheric Nitrogen ◽  
Pure Nitrogen ◽  
Preliminary Note ◽  
Reduced Pressure ◽  
Spectroscopic Examination ◽  
James Dewar ◽  
Antagonistic Muscles

I. “Application of Liquid Hydrogen to the Production of High Vacua, and their Spectroscopic Examination.” By James Dewar, LL.D., F. R. S. II. “On the Boiling Point of Liquid Hydrogen under reduced Pressure.” By James Dewar, LL.D., F. R. S. III. “Ionic Velocities.” By Orme Masson. Communicated by Professor Ramsay, F. R. S. IV. “Note on the Densities of ‘Atmospheric Nitrogen,’ Pure Nitrogen, and Argon.” By William Ramsay, F. R. S. V. “The Preparation and some of the Properties of Pure Argon.” By William Ramsay, F. R. S., and Dr. Morris W. Travers. VI. “Observations on the Anatomy, Physiology, and Degenerations of the Nervous System of the Bird.” By R. Boyce and W. B. Warrington. Communicated by Professor Sherrington, F. R. S. VII. “The Action of Magnetised Electrodes upon Electrical Discharge Phenomena in Rarefied Gases. Preliminary Note.” By C. E. S. Phillips. Communicated by Sir William Crookes, F. R. S. VIII. “On the Reciprocal Innervation of Antagonistic Muscles. Fifth Note.” By C. S. Sherrington, M.A., M.D., F. R. S.

scholarly journals On the boiling point of liquid hydrogen under reduced pressure

1899 ◽  
Vol 64 (402-411) ◽  
pp. 227-231
Keyword(s):  
Boiling Point ◽  
Chemical Society ◽  
Liquid Hydrogen ◽  
Platinum Wire ◽  
Resistance Thermometer ◽  
Reduced Pressure ◽  
Different Temperatures

The June number of the ‘Proceedings of the Chemical Society’ contains a paper by the author on “The Boiling Point and Density of Liquid Hydrogen.” A resistance thermometer made of fine platinum wire, called No. 7 Thermometer, was used in the investigation. It had been carefully calibrated, and gave the following resistances at different temperatures:— The zero of the thermometer in platinum degrees was —263⋅27°.

scholarly journals The liquefaction of helium by an adiabatic method

1934 ◽  
Vol 147 (860) ◽  
pp. 189-211 ◽  
Keyword(s):  
Liquid Helium ◽  
High Pressures ◽  
Scientific Work ◽  
Liquid Hydrogen ◽  
Thermal Capacity ◽  
Liquid Oxygen ◽  
Reduced Pressure ◽  
External Work ◽  
Adiabatic Principle ◽  
Continuous Output

The liquefaction of helium by Kammerlingh Onnes has led in the past thirty years to discoveries of the greatest importance to the study of the solid state. In spite of this, very few laboratories are now equipped with the apparatus necessary for the production of liquid helium. It is therefore very desirable that the complicated technique necessary for its production should be simplified to allow of its more extensive use. In this paper we shall describe a more efficient liquefier, based on an adiabatic principle, which we hope will considerably simplify the production of liquid helium for scientific work. At present two principal methods are used for the cooling and liquefying of gases. The first method is based on cooling produced by adiabatic expansion where the expanding gas is cooled by doing external work. This phenomenon was observed by Clèment and Desormes in 1819 when they discovered the cooling of a gas in a container when its pressure was reduced by letting out some of the gas through a tap. It can be shown that on expanding, the gas remaining in the container has done work in communicating kinetic energy to the escaped gas, and therefore has been cooled adiabatically. Olszewski in 1895 applied this method to the liquefaction of hydrogen; he compressed the gas to 190 atmospheres and pre-cooled it with liquid oxygen boiling at reduced pressure (-211°C); on releasing the pressure, he observed a fog of liquid hydrogen drops. From this experiment he was able to determine the critical data for hydrogen. This method has also been used recently by Simon for liquefying helium. Simon took advantage of the fact that at very low temperatures the thermal capacity of the container is so small that it practically absorbs no cold from the liquefied helium. The limitations of this method are that it can only conveniently be applied for obtaining small amounts of liquid helium; it is not suited for a continuous output of helium, and also there is necessarily a loss of cold due to the gas which leaves the container. The method is also complicated by the fact that high pressures are required, and that pre-cooling with liquid hydrogen boiling at reduced pressure is necessary.

scholarly journals The influence of pressure on the boiling points of metals

1910 ◽  
Vol 83 (565) ◽  
pp. 483-491 ◽  
Keyword(s):  
Atmospheric Pressure ◽  
Boiling Point ◽  
High Vacuum ◽  
Similar Type ◽  
Exact Relation ◽  
Reduced Pressure ◽  
Boiling Points ◽  
Experimental Values ◽  
Low Pressures ◽  
Very High

Part I. — Pressures below 760 mm . In a previous communication (‘Proc.’, A, vol. 82, 1909, p. 396) the approximate boiling points of a number of metals were determined at atmospheric pressure. Apart from the question of finding the exact relation between the boiling point and pressure, it is an important criterion of any method for fixing the temperatures of ebullition to demonstrate that the experimental values obtained are dependent on the pressure. It is specially desirable when dealing with substances boiling at temperatures above 2000° to have some evidence that the points indicated are true boiling points. Previous work on the vaporisation of metals at different pressures has been confined to experiments in a very high vacuum except for metals like bismuth, cadmium, and zinc, which boil at relatively low temperatures under atmospheric pressure. The observations were limited to very low pressures on account of the difficulty of obtaining any material capable of withstanding a vacuum at temperatures over 1400° and the consequent necessity for keeping the boiling point below this limit by using very low pressures. Moreover in the case of the majority of the metals, e. g. , copper, tin, ebullition under reduced pressure has never been observed. The difficulties indicated above were avoided by using a similar type of apparatus to that previously described, and arranging the whole furnace inside a vacuum enclosure, thus permitting of the use of graphite crucibles to contain the metal.

scholarly journals The constitution of sulphur vapour

1919 ◽  
Vol 95 (672) ◽  
pp. 484-492 ◽  
Keyword(s):  
Boiling Point ◽  
Diatomic Molecules ◽  
Conclusive Evidence ◽  
The Other ◽  
Molecular Formula ◽  
Reduced Pressure ◽  
Vapour Density ◽  
Temperature And Pressure ◽  
Sulphur Vapour

The constitution of sulphur vapour has been studied by many investigators, the method usually employed being based upon the determination of the density. In 1835 Dumas and Mitscherlich found the vapour density at temperatures near the boiling point to be 6∙56, which corresponds closely with the molecular formula S 6 . Deville and Troost carried out determinations at temperatures ranging from 860°C to 1040°C. and obtained the value 2∙23 which is that required by the formula S 2 . More recently Biltz has shown that below 800°C. the density is greater than is required by the formula S 2 , and at 468°C. becomes 7∙8 which corresponds approximately to the formula S 7 , without any constant value being observed between these temperatures. Bleier and Kohn found that when determinations were made under reduced pressure between 192°C. and 310°C. the density of the vapour gradually rose with increase of pressure and slowly but asymptotically approached the value S 8 . Evidence of the existence of molecules containing eight atoms has also been obtained from an examination of solutions of sulphur. Biltz holds that the value obtained by Dumas and Mitscherlich is only of significance for the conditions of temperature and pressure under which it was determined, and affords no evidence of the presence of hexatomic molecules in the vapour. His view is that only octatomic and diatomic molecules have any existence, the former gradually dissociating into the latter as the temperature is raised until about 900° C., the dissociation of the heavier molecules is complete and the vapour is composed entirely of diatomic molecules. Above this temperature no further change appears to occur. Premier, on the other hand, from a study of the curve representing the change of density with change of pressure considers that it is not unlikely that hexatomic and tetratomic molecules are formed as intermediate pro­ducts of the dissociation of the octatomic molecules. Of this, however, the investigation of the vapour density does not afford any conclusive evidence.

scholarly journals A new formation of diamond

1905 ◽  
Vol 76 (512) ◽  
pp. 458-461 ◽  
Keyword(s):  
Critical Temperature ◽  
Melting Point ◽  
Critical Point ◽  
Boiling Point ◽  
Critical Pressure ◽  
Carbonic Acid ◽  
Melting Points ◽  
Boiling Points ◽  
James Dewar ◽  
New Formation

On the average the critical point of a substance is 1·5 times its absolute boiling-point. Therefore the critical point of carbon should be about 5800° Ab. But the absolute critical temperature divided by the critical pressure is for all the elements so far examined never less than 2·5; this being about the value Sir James Dewar finds for hydrogen. So that, accepting this, we get the maximum critical pressure as follows, viz., 2320 atmospheres:— 5800° Ab./CrP = 2·5, or CrP = 5800° Ab./2·5, or 2320 atmospheres. Carbon and arsenic are the only two elements that have melting-point above the boiling-point; and among compounds carbonic acid and fluoride of silicium are the only other bodies with similar properties. Now the melting-point of arsenic is about 1·2 times its absolute boiling-point. With carbonic acid and fluoride of silicium the melting-points are about 1·1 times their boiling-points. Applying these ratios to carbon we find that its melting-point would be about 4400°.

scholarly journals The boiling point of liquid hydrogen, determined by hydrogen and helium gas thermometers

1901 ◽  
Vol 68 (442-450) ◽  
pp. 44-54 ◽  
Keyword(s):  
Boiling Point ◽  
Liquid Hydrogen ◽  
Platinum Resistance Thermometer ◽  
Platinum Resistance ◽  
Resistance Thermometer ◽  
Helium Gas ◽  
Empirical Law

In a former paper it was shown that a platinum-resistance thermometer gave for the boiling point of hydrogen - 238°-4 C., or 34°-6 absolute. As this value depended on an empirical law correlating temperature and resistance, which might break down at such an exceptional temperature, and was in any case deduced by a large extrapolation, it became necessary to have recourse to the gas thermometer.

Theoretical Estimate of Cooling Time of a Liquid Hydrogen Tank during Structural Tests

2021 ◽  
pp. 83-89
Author(s):  
N.O. Borschev ◽  
O.A. Yuranev
Keyword(s):  
Boiling Point ◽  
Theoretical Estimate ◽  
Experimental Tests ◽  
Liquid Hydrogen ◽  
Cooling Time ◽  
Space Vehicles ◽  
Gaseous State ◽  
Temperature State ◽  
Structural Tests ◽  
Cryogenic Propellants

Russian enterprises continue developing rocket and space vehicles based on cryogenic propellants, i.e. liquid hydrogen, oxygen, and methane. Hence, the issues of fuel tanks’ thermal strength are increasingly important. During structural tests, the operating temperatures of the test object should be simulated, since the temperature condition affects the strength and rigidity of the structure. Consequently, during ground-based experimental tests, hydrogen tanks must be cooled down to 20 K, the boiling point of hydrogen. JSC TsNIIMash is developing a helium system capable of cooling large-sized structures to a temperature of 20 K. Helium can be used in a gaseous state to cool down the structure, since the boiling point of helium, 4 K, is lower than the boiling point of hydrogen. Until now, the tanks were cooled only by filling with liquid nitrogen, therefore the temperature state of the tanks during the tests was simulated only for this case. In order to determine the applicability of the method developed, the cooling time of large-sized containers was estimated by cooling a hydrogen tank, which by its dimensions is typical for an advanced medium-class second stage launcher, to 20 K by gaseous helium.

scholarly journals The viscosity of liquid helium

1935 ◽  
Vol 151 (873) ◽  
pp. 342-347 ◽  
Author(s):  
J. O. Wilhelm ◽  
A. D. Misener ◽  
A. R. Clark ◽  
John Cunningham McLennan
Keyword(s):  
Liquid Helium ◽  
Vapour Pressure ◽  
Boiling Point ◽  
Fine Particles ◽  
Apparent Difference ◽  
Reduced Pressure ◽  
Helium Ii ◽  
Λ Point

It is a well-known fact that liquid helium changes from one form of liquid to another at a temperature of 2.19º K, under its own vapour pressure at that temperature. The liquid above this temperature is spoken of as helium I, and below it, as helium II. This temperature is known as the λ point. The apparent difference between these two forms of the liquid is that helium I visibly boils as it is being evaporated in a way similar to ordinary liquids, but immediately this temperature is passed boiling stops and the liquid appears to be absolutely quiescent, although the temperature is progressively reduced by continued evaporation. Many properties of these two forms of liquid helium have been studied, but apparently up to the present the viscosity has not been determined. In order to keep the liquid helium at a given temperature below 4.2º K, its boiling point, it is necessary to allow it to boil under reduced pressure, consequently the formation of bubbles excludes any possibility of using a capillary viscosimeter method. The necessity of operating the liquefying system under reduced pressure also allows small amounts of impurity to leak in; these traces of impurity condense over the liquid helium and drop as fine particles through the liquid. This has to be considered in designing the apparatus.

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