An experimental determination of the melting curves of argon and nitrogen into the 10000 atm region

1954 ◽  
Vol 225 (1162) ◽  
pp. 393-405 ◽  
Keyword(s):  
Low Temperatures ◽  
Room Temperature ◽  
Small Volume ◽  
High Pressures ◽  
Steel Tube ◽  
Melting Curves ◽  
New Apparatus ◽  
Very High ◽  
Small Steel

A new apparatus for measuring melting curves at low temperatures and very high pressures is described. It is essentially a combined cryostat and high-pressure intensifier connected by a single junction at room temperature. The pressure is produced in a number of stages culminating in a single intensification stroke on to a small volume of gas maintained at low temperatures in a long steel tube. Solidification and melting are detected in this tube by means of a small steel pellet, which may be moved by an external magnetiċ field when the substance is fluid. Experiments have been carried out on argon and nitrogen. The solid-fluid equilibrium line has been extended to 8250 atm at 234° K for argon, and to 9100 atm at 180° K for nitrogen.

Applications: Light My Fire

1982 ◽  
Vol 75 (1) ◽  
pp. 53-55
Author(s):  
George Knill ◽  
George Fawceti
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Low Temperatures ◽  
Chemical Process ◽  
Room Temperature ◽  
Very High

Everyone knows that wood bums at a very high temperature. This burning is a chemical process that combines oxygen and carbon. The process occurs at very low temperatures as well as at very high ones. At high temperatures the process is spectacular-fire. At low temperatures (room temperature) you won’t even notice it, although it is still going on. Wood is always burning.

Elektrochemische Synthesen, XIV [1] Radikalkation-Salze des Naphthalins / Electrochemical Syntheses, XIV [1]. Radical Cation Salts of Naphthalene

1978 ◽  
Vol 33 (5) ◽  
pp. 498-506 ◽  
Author(s):  
Heinz P. Fritz ◽  
Helmut Gebauer ◽  
Peter Friedrich ◽  
Peter Ecker ◽  
Reinhold Artes ◽  
...  
Keyword(s):  
Radical Cation ◽  
Low Temperatures ◽  
Room Temperature ◽  
Specific Conductivity ◽  
Columnar Structure ◽  
Screw Axis ◽  
Radical Cation Salts ◽  
Difference Fourier ◽  
Pure Hydrocarbon

Abstract By anodic oxidation of naphthalene in H2CCl2/O.O2m Bu4NPF6 at -45 °C dark red-violet crystals of (C10H8)2PF6 can be obtained by electrocrystallisation. They are stable at low temperatures, however, decompose on warming. In solution and in the polycrystalline state these radical cation salts show only narrow e.p.r. signals without h.f.s. The specific conductivity of a polycrystalline pellet at room temperature was determined to be 0.12 ±0.046 Ohm-1 cm-1 . The structure determination of (C10H8)2PF6 yielded the tetragonal space group P42/n, Z = 2, a = b = 1156(2), c = 640(1) pm. Patterson synthesis and difference Fourier analyses showed the compound to have a columnar stacking of C10H8 units the long molecular axes of which are twisted alternately by 90° around a screw axis in c-direction, and the molecular planes of which are 320 pm apart. The PF6-ions have four nearest C10H8 neighbours lying in pairs in parallel planes 63 pm above and below that plane of PF6- perpendicular to the c-axis and containing a PF4 group. This is the first established case for a columnar structure of a pure hydrocarbon radical cation. (C10H8)2AsF6 is isomorphous.

scholarly journals An experiment with the balance to find if change of temperature has any effect upon weight

1905 ◽  
Vol 76 (512) ◽  
pp. 445-457 ◽  
Keyword(s):  
Low Temperatures ◽  
Secondary Effect ◽  
Boiling Liquid ◽  
The Earth ◽  
Exact Determination ◽  
The Mean ◽  
Very High ◽  
The Ideal

In all the experiments hitherto made to determine the gravitative attraction between two masses, the temperature has not varied more than a few degrees, and there are no results which would enable us to detect with certainty any dependence of attraction upon temperature even if such dependence exists. It is true, as Professor Hicks has pointed out, that Baily’s results for the Mean Density of the Earth, if arranged in the order of the temperature of the apparatus when they were obtained, show a fall in value as the temperature rises. But this is almost certainly some secondary effect, due to errors in the measurements of the apparatus, or to the seasons at which different attracted masses were used. The ideal experiment to find if temperature has an effect on gravitation would consist in one determination of the gravitative attraction between two masses at, say 15°C., and another determination at, say, the temperature of boiling liquid air. But the difficulties of exact determination at ordinary temperatures are not yet overcome, and at any very high or very low temperatures, they would be so much increased that the research seems at present hopeless.

The Microstructure of Diene Polymers. II. Polyisoprenes and Polybutadienes Prepared at High Pressures

1954 ◽  
Vol 27 (4) ◽  
pp. 958-961
Author(s):  
W. S. Richardson
Keyword(s):  
Free Radical ◽  
Hydrostatic Pressure ◽  
Chemical Reactions ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
High Pressures ◽  
Bulk Polymerization ◽  
Extensive Investigation ◽  
Very High ◽  
Increased Pressure

Abstract The rapid bulk polymerization of isoprene at room temperature under high hydrostatic pressure was apparently first observed by Bridgman and Conant. A more extensive investigation by Conant and Tongberg established the free radical nature of the polymerization (peroxide catalysis and hydroquinone inhibition). The latter workers also noted the solubility and elasticity of polymers made to moderate conversion and the insoluble crumbly nature (gelation) of the polymers made to very high conversion. In view of the well known effect of increased pressure in driving chemical reactions in the direction of the products of least specific volume, it is of interest to consider the possibility that diene polymers made at high pressures may be different in microstructure from polymers made at comparable temperatures but near atmospheric pressure.

Substantiation of a Technique of Determining Stress in Thin Films at Very Low Temperatures

2015 ◽  
Vol 14 ◽  
pp. 28-36
Author(s):  
C.C. Chama
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Low Temperatures ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
High Temperature Stress ◽  
Hysteresis Curves ◽  
Stress Hysteresis

Substantiation of a technique earlier employed in determining stress in Copper-Silver thin films at very low temperatures is presented. It is shown that the stress measured at elevated temperatures using Stoney’s equation can be utilized in the determination of stress at very low temperatures. To demonstrate the application of this technique, a case study has been conducted by utilizing stress hysteresis curves obtained from the Cu-6at%Ag thin film heated from room temperature to 400°C and cooled back to room temperature in two cycles. The stresses in the Cu-6at%Ag thin film at various low temperatures up to-197°C have been determined by utilizing data from high temperature stress hysteresis curves.

Cold Consolidation of Powder by Hydrostatic Extrusion

1974 ◽  
Vol 188 (1) ◽  
pp. 639-645 ◽  
Author(s):  
R. L. Hewitt ◽  
W. Wallace ◽  
M. C. Demalherbe
Keyword(s):  
Strain Hardening ◽  
Metal Powder ◽  
Room Temperature ◽  
High Pressures ◽  
Hydrostatic Extrusion ◽  
Bonding Mechanism ◽  
Similar Composition ◽  
Isostatic Compaction ◽  
Very High ◽  
Strength Improvement

The isostatic compaction and hydrostatic extrusion of two atomized powders, namely Alcoa grade 1202 aluminium and Atomet 28 iron, are described and it is shown that the extrusion pressures for these powders may be 50-100 per cent greater than for an equivalent wrought material. Results of mechanical testing and metallographic and fractographic examinations of the extruded aluminium compacts are presented which show that good bonding can be developed by hydrostatic extrusion at ratios of 6·25 and that the resultant strengths can be higher than that of wrought material of a similar composition. This strength improvement is attributed to the strain hardening undergone by the materials during compaction. An interpretation of the bonding mechanism is also given. Although it has been shown that isostatic compaction and hydrostatic extrusion can be combined to produce well-bonded bar material from metal powder at room temperature, it is suggested that the method is limited by the very high pressures that would be required to produce materials of commercial interest.

scholarly journals The isotherms of CO 2 in the neighbourhood of the critical point and round the coexistence line

1937 ◽  
Vol 160 (902) ◽  
pp. 358-375 ◽  
Keyword(s):  
Critical Point ◽  
Steel Tube ◽  
Pure Nitrogen ◽  
Steel Vessel ◽  
Critical Data ◽  
Diagrammatic Sketch ◽  
New Apparatus ◽  
Coexistence Line ◽  
The One

The isotherms of CO 2 between 0 and 150°C. and up to 3000 atm. have been previously published by two of the authors (Michels, A. and C. 1935). The method used for these measurements was not suitable, however, for determinations in the neighbourhood of the critical point and the coexistence line. A second method has therefore been developed by which both the critical data and the coexistence line can be determined. This method and the results obtained are described in the present paper. The Method and Apparatus The method was based on the one developed by Michels and Nederbragt (1934) for the determination of the condensation points of a binary mixture. While, however, for the measurements of condensation points, it was not necessary to know the quantity of gas in the apparatus, this knowledge is essential for the determination of isotherms. A new apparatus was therefore constructed in which this quantity could be determined. A diagrammatic sketch showing the principle employed is given in fig. 1. In a steel vessel A , a glass bell B is suspended which is connected through the steel valve H and the capillary J to a cylinder containing a supply of the gas to be examined. A steel capillary C connects A with a second steel vessel D , placed on one scale pan of a balance. Inside D a steel tube E , which is coupled to C , reaches to the bottom. The capillary F is connected to the top of D and leads to a cylinder of pure nitrogen and to an apparatus for measuring the gas pressure. The capillaries C and F are flexible, and are supported at G at such a distance from the scale pan that the variations in the forces acting on the latter during the swinging can be neglected. Before starting the measurements, the vessels A , the glass bell B and the tube C are completely, and the vessel D is partly filled with mercury. The valve H is then opened and CO 2 gas admitted to the glass bell, driving mercury out of A into D . The pressure in D is balanced by nitrogen introduced through F . When sufficient CO 2 has entered the glass bell, the valve H is shut. As the filling operation is carried out at a temperature and pressure at which the isotherms of CO 2 are known, the amount of gas in B can be calculated from a knowledge of the volume.

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