The Possible Importance of Pressure in Metastable Precipitate Formation in Ion Implanted Metals

1988 ◽  
Vol 100 ◽  
Author(s):  
John H. Evans
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Solid Phase ◽  
Inert Gas ◽  
Fine Scale ◽  
Host Matrix ◽  
Driven Cavity ◽  
Precipitate Formation ◽  
Very High ◽  
Metastable Precipitate

ABSTRACTPrompted by the recent discovery that the heavier inert gas atoms implanted into metals precipitate in the solid phase, indicative of very high pressures (,>,1 GPa), the present paper discusses the conditions under which such pressures might be expected. The metal/inert gas results are briefly described and then used as a model to show that the two essential features apart from low or moderate metal temperatures, are the insolubility of the implanted species in the host matrix and its precipitation on a very fine scale. This combination suppresses the bias-driven cavity swelling that would otherwise control vacancy acquisition in an irradiation environment.The extrapolation to other combinations of implanted ion and metal will be discussed. Where the implanted ion is insoluble and precipitates on a scale similar to the inert gas atoms, exact analogy suggests that the precipitates will again be under high pressure. The formation of high pressure phases might not be unexpected and could be a factor in explaining the presence of phases previously thought to be metastable.

scholarly journals Gaseous combustion at high pressures. —Part X. The co-volume corrections, maximum temperatures and dissociation of steam and carbon dioxide in explosions

1928 ◽  
Vol 119 (782) ◽  
pp. 464-480
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Internal Energy ◽  
High Temperatures ◽  
High Pressures ◽  
Internal Combustion ◽  
Systematic Survey ◽  
Explosion Method ◽  
Maximum Temperatures ◽  
Very High

During the researches upon high-pressure explosions of carbonic oxide-air, hydrogen-air, etc., mixtures, which have been described in the previous papers of this series, a mass of data has been accumulated relating to the influence of density and temperature upon the internal energy of gases and the dissociation of steam and carbon dioxide. Some time ago, at Prof. Bone’s request, the author undertook a systematic survey of the data in question, and the present paper summarises some of the principal results thereof, which it is hoped will throw light upon problems interesting alike to chemists, physicists and internal-combustion engineers. The explosion method affords the only means known at present of determining the internal energies of gases at very high temperatures, and it has been used for this purpose for upwards of 50 years. Although by no means without difficulties, arising from uncertainties of some of the assumptions upon which it is based, yet, for want of a better, its results have been generally accepted as being at least provisionally valuable. Amongst the more recent investigations which have attracted attention in this connection should be mentioned those of Pier, Bjerrum, Siegel and Fenning, all of whom worked at low or medium pressures.

Solid-phase polymerizations at high pressures

1970 ◽  
Vol 23 (3) ◽  
pp. 511 ◽  
Author(s):  
MG Bradbury ◽  
SD Hamann ◽  
M Linton
Keyword(s):  
High Pressure ◽  
Spectral Analysis ◽  
Solid State ◽  
High Pressures ◽  
Solid Phase ◽  
Crystal Form ◽  
Optical Cell ◽  
Itaconic Anhydride ◽  
Temperature Requirements ◽  
Infrared Spectral

The following compounds have been found to polymerize spontaneously in the solid state at pressures in the range 10-50 kbar, at temperatures between 20 and 200�C: acrylamide, p-phenylstyrene, potassium p-styrenesulphonate, itaconic anhydride, maleic anhydride, maleimide, 1,2,3,6-tetrahydrophthalic acid, 1,2,3,6-tetrahydrophthalic anhydride, acenaphthylene, p-benzoquinone, N,N'-p-phenylene-dimaleimide, sulpholene, diphenylacetylene, 8-trioxan. The pressure-temperature requirements for polymerization have been determined in a high-pressure "squeezer" apparatus and in a diamond optical cell which permits infrared spectral analysis of a specimen while it is under compression. Apart from diphenylacetylene and trioxan, the compounds that polymerized were either monosubstituted ethylenes or cyclic 1,2-disubstituted ethylenes. Non-cyclic 1,2-disubstituted ethylenes and tri-substituted and tetra-substituted ethylenes failed to polymerize. There is evidence that shearing stresses played a part in some of the reactions. 1-Allyl-2-thiourea did not polymerize, but transformed from its stable crystal form I to the unstable modification 11.

scholarly journals Ultra High Pressure Liquid Chromatography for Crude Plant Extract Profiling

2011 ◽  
Vol 94 (1) ◽  
pp. 51-70 ◽  
Author(s):  
Philippe J Eugster ◽  
Davy Guillarme ◽  
Serge Rudaz ◽  
Jean-Luc Veuthey ◽  
Pierre-Alain Carrupt ◽  
...  
Keyword(s):  
High Pressure ◽  
Liquid Chromatography ◽  
High Pressure Liquid Chromatography ◽  
High Pressures ◽  
Product Analysis ◽  
Basic Principles ◽  
Ultra High Pressure ◽  
Crude Plant Extract ◽  
Phase Chemistry ◽  
Very High

Abstract Ultra high pressure liquid chromatography (UHPLC) systems operating at very high pressures and using sub-2 μm packing columns have allowed a remarkable decrease in analysis time and increase in peak capacity, sensitivity, and reproducibility compared to conventional HPLC. This technology has rapidly been widely accepted by the analytical community and is being gradually applied to various fields of plant analysis such as QC, profiling and fingerprinting, dereplication, and metabolomics. For many applications, an important improvement of the overall performances has been reported. In this review, the basic principles of UHPLC are summarized, and practical information on the type of columns used and phase chemistry available is provided. An overview of the latest applications to natural product analysis in complex mixtures is given, and the potential and limitations as well as some new trends in the development of UHPLC are discussed.

scholarly journals First-principles study of SnO under high pressure

2016 ◽  
Vol 30 (31) ◽  
pp. 1650228 ◽  
Author(s):  
M. A. Ali ◽  
A. K. M. A. Islam ◽  
N. Jahan ◽  
S. Karimunnesa
Keyword(s):  
High Pressure ◽  
Optical Properties ◽  
First Principles ◽  
High Pressures ◽  
Mechanical Stability ◽  
Generalized Gradient ◽  
First Principles Study ◽  
Anisotropic Factor ◽  
High Anisotropy ◽  
Very High

This paper reports the first-principles study of SnO under high pressure within the generalized gradient approximation (GGA). We have calculated the structural, elastic, electronic and optical properties of SnO. The elastic properties such as the elastic constants [Formula: see text], bulk modulus, shear modulus, Young’s modulus, anisotropic factor, Pugh’s ratio and Poisson’s ratio are calculated and analyzed. Mechanical stability of SnO at all pressures is confirmed using the Born’s stability conditions in terms of [Formula: see text]. It is also found that SnO exhibits very high anisotropy. The energy band structure and density of states are also calculated and analyzed. The results show the semiconducting and metallic properties at zero and high pressures, respectively. Furthermore, the optical properties are also calculated. All the results are compared with those of SnO where available but most of the results at high pressure are not compared due to the unavailability of results.

Pressurfect™ CNG-Advanced Material Grade for High Pressure CNG Fuel Line Applications

2017 ◽  
Author(s):  
Vikram Pandit
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Extensive Study ◽  
Stainless Steel 316L ◽  
Gas Stations ◽  
Production Route ◽  
Pressure Line ◽  
The People ◽  
The Government ◽  
Very High

In line with the government of India’s philosophy of going green to reduce emission levels in cities there is a thrust to increase the gas distribution network. With an increase in CNG vehicles, comes the safety of the people and we need to ensure that Safety is not comprised at any level. To follow the Safety aspect, CNG is an excellent alternate fuel which can be used to minimize risks and increase life of the vehicles. Since this gas is used at very high pressures (in the range of 230–250 bar) and under severe conditions, special tubing must be used for the transportation to gas stations and in the vehicles. Therefore, the tubing should be able to not only withstand high pressure of the gas within but also the corrosion issues arising due to the extreme conditions the tubes within. Sandvik did an extensive study of the conditions and came up with a material which is specifically developed for this high pressure application. The high pressure line is of Stainless Steel 316L but this material comes with certain modifications for this particular requirement. In this tubing the C content is lowered to 0.025% for better corrosion resistance, Ni is min 13% along with Mo min 2.5% this makes sure that the material not only has sufficient passivation properties but the strength also to withstand that kind of a pressure. Alongside a special production route also has been developed for the manufacturing of these tubing. This ensures Safety for the people throughout the life of the vehicle.

The influence of mean contact pressure on the friction coefficient of a traction fluid at high pressure

2000 ◽  
Vol 214 (2) ◽  
pp. 309-312 ◽  
Author(s):  
M F Workel ◽  
D Dowson ◽  
P Ehret ◽  
C M Taylor
Keyword(s):  
High Pressure ◽  
Friction Coefficient ◽  
Contact Pressure ◽  
High Pressures ◽  
Friction Coefficients ◽  
Ball Impact ◽  
Good Consistency ◽  
Traction Fluid ◽  
Very High

A new ball impact apparatus has been developed for measuring the friction coefficients of solidified lubricants under very high pressures. Results obtained for Santotrac 50 showed a decrease in friction coefficient with increasing mean contact pressure and showed good consistency with values reported elsewhere from several different forms of apparatus.

Seismic parameter φ: Computation at very high pressure from laboratory data

1966 ◽  
Vol 56 (3) ◽  
pp. 725-731
Author(s):  
Orson L. Anderson
Keyword(s):  
High Pressure ◽  
Bulk Modulus ◽  
Ultrasonic Velocity ◽  
Pressure Range ◽  
High Pressures ◽  
Equations Of State ◽  
Laboratory Data ◽  
Second Derivative ◽  
Velocity Measurements ◽  
Very High

abstract By using the accuracy inherent in ultrasonic velocity measurements taken at pressures less than 10 kb, the seismic parameter φ=vp2−(43)vS2 can be computed at very high pressures. The equation used requires the assumption that the second derivative with respect to pressure of the bulk modulus be negligible at all pressures considered. This assumption is checked by computing the compression (V/V0) in the pressure range by equations of state using the assumption, and comparing the resulting values with measured compression. Illustrations are given for MgO and Al2O3.

The Pressure-temperature Phase and Reaction Diagram for Carbon

1995 ◽  
Vol 383 ◽  
Author(s):  
Francis P. Bundy
Keyword(s):  
Melting Temperature ◽  
Triple Point ◽  
High Pressures ◽  
Solid Phase ◽  
Theoretical Calculations ◽  
Closed Surface ◽  
Temperature Phase ◽  
Stable Form ◽  
Metallic State ◽  
Very High

ABSTRACTCarbon atoms form very strong bonds to each other, yielding materials like: (i) crystalline graphite, diamond and their many “amorphous” hybrids; (ii) crystalline forms of giant closed–surface molecules such as the fullerenes; and (iii) liquid and gas phases which have molecular contents which are complicated and not yet defined or understood. Because of the high bonding energy the melting and vaporization temperatures of the solid forms are very high, and the activation energies required to transform one solid form to another are large. One consequence is that at lower temperatures the different solid phases may continue to exist metastably far into a P, T region in which another solid phase is the thermodynamically stable one.In the thermodynamic sense the vapor pressure line of graphite, the graphite/liquid/vapor triple point, the graphite melting line, the graphite/diamond equilibrium line, and the graphite/diamond/liquid triple point are quite well established. Data for the melting temperature of diamond vs. pressure are sparse and rough, but they indicate that the melting temperature increases with pressure,-in agreement with some theories. Although carbon should transform to a solid metallic state at very high pressures, experimental evidence shows diamond to be stable to over 400GPa, and theoretical calculations indicate that it could be the stable form up to pressures of 1200 to 2300GPa. Attention is given to the solid state transformations which can take place when graphite is compressed and heated along different P, T paths under different conditions.

scholarly journals High-pressure Seebeck coefficients and thermoelectric behaviors of Bi and PbTe measured using a Paris-Edinburgh cell

2016 ◽  
Vol 23 (6) ◽  
pp. 1368-1378 ◽  
Author(s):  
Jason Baker ◽  
Ravhi Kumar ◽  
Changyong Park ◽  
Curtis Kenney-Benson ◽  
Andrew Cornelius ◽  
...  
Keyword(s):  
High Pressure ◽  
Seebeck Coefficient ◽  
Structural Changes ◽  
High Pressures ◽  
Solid Phase ◽  
Thermal Conductance ◽  
X Ray Diffraction ◽  
Seebeck Coefficients ◽  
Assembly Design ◽  
Relative Change

A new sample cell assembly design for the Paris-Edinburgh type large-volume press for simultaneous measurements of X-ray diffraction, electrical resistance, Seebeck coefficient and relative changes in the thermal conductance at high pressures has been developed. The feasibility of performingin situmeasurements of the Seebeck coefficient and thermal measurements is demonstrated by observing well known solid–solid phase transitions of bismuth (Bi) up to 3 GPa and 450 K. A reversible polarity flip has been observed in the Seebeck coefficient across the Bi-I to Bi-II phase boundary. Also, successful Seebeck coefficient measurements have been performed for the classical high-temperature thermoelectric material PbTe under high pressure and temperature conditions. In addition, the relative change in the thermal conductivity was measured and a relative change in ZT, the dimensionless figure of merit, is described. This new capability enables pressure-induced structural changes to be directly correlated to electrical and thermal properties.

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