THE DETERMINATION OF THE SATURATION VAPOR PRESSURE OF SOLID HYDROXYLAMINE USING A PISTON PRESSURE GAUGE

1965 ◽  
Vol 43 (8) ◽  
pp. 2157-2161 ◽  
Author(s):  
R. A. Back ◽  
J. Betts
Keyword(s):  
Vapor Pressure ◽  
Dissociation Energy ◽  
Pressure Gauge ◽  
Saturation Vapor Pressure ◽  
Vapor Density ◽  
Kcal Mole ◽  
Density Measurements ◽  
Glass Cylinder ◽  
Saturation Vapor

The saturation vapor pressure of solid hydroxylamine has been determined at temperatures from −12 to 7° C and found to fit the equation[Formula: see text]From this have been calculated several thermochemical quantities, including a heat of sublimation of 15.34 kcal/mole, and a dissociation energy of 61.3 kcal/mole for the NH2—OH bond. Vapor density measurements showed that hydroxylamine vapor consisted of single molecules of NH2OH at 0.27 Torr and 25 °C.A novel pressure gauge used in the measurements is described. Pressures were determined with an accuracy of ±0.001 Torr by measuring the force acting on a piston, moving freely in a glass cylinder, suspended on the arm of a torsion balance.

STRUCTURE OF PYROLYZED POLYVINYLIDENE CHLORIDE

1963 ◽  
Vol 41 (1) ◽  
pp. 180-190 ◽  
Author(s):  
J. R. Dacey ◽  
R. G. Barradas
Keyword(s):  
Vapor Pressure ◽  
Structural Changes ◽  
Spectral Studies ◽  
Saturation Vapor Pressure ◽  
Polyvinylidene Chloride ◽  
Complementary Technique ◽  
Mechanism Of Decomposition ◽  
Porosity Measurements ◽  
Saturation Vapor

Systematic infrared analyses, using the standard KBr pellet technique, of samples ranging from the pure polymer (Saran) to the fully carbonized charcoal have been examined in an attempt to clarify the structural changes and mechanism of decomposition of the polymer on pyrolysis. A complementary technique has been investigated for obtaining homogeneous samples of the carbon and of the partially pyrolyzed polymer which will transmit infrared radiation without the use of any halide dispersal medium. The significance, possible applications, and limitations of these spectral studies are discussed. Pore volumes have been examined by means of a modified helium displacement densitometer and also through the adsorption of argon in a McBain–Bakr balance. Porosity measurements based on the adsorption of argon at its saturation vapor pressure are more satisfactory and they contribute towards a better understanding of the microstructure of Saran charcoal and of its partially carbonized antecedents. The influence of pelletizing pressure has been found to play an important role in the determination of pore volumes.

Determination of the saturation vapor pressure of silicon by Knudsen cell mass spectrometry

2012 ◽  
Vol 57 (2) ◽  
pp. 219-225 ◽  
Author(s):  
S. I. Lopatin ◽  
V. L. Stolyarova ◽  
V. G. Sevast’yanov ◽  
P. Ya. Nosatenko ◽  
V. V. Gorskii ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Vapor Pressure ◽  
Cell Mass ◽  
Knudsen Cell ◽  
Saturation Vapor Pressure ◽  
Cell Mass Spectrometry ◽  
Knudsen Cell Mass Spectrometry ◽  
Saturation Vapor

Experimental and theoretical determination of the saturation vapor pressure of silicon in a wide range of temperatures

2010 ◽  
Vol 55 (13) ◽  
pp. 2073-2088 ◽  
Author(s):  
V. G. Sevast’yanov ◽  
P. Ya. Nosatenko ◽  
V. V. Gorskii ◽  
Yu. S. Ezhov ◽  
D. V. Sevast’yanov ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Saturation Vapor Pressure ◽  
Theoretical Determination ◽  
Wide Range ◽  
Saturation Vapor

scholarly journals Increased Accumulation On The Antarctic Ice Sheet Due To Climatic Warming

1990 ◽  
Vol 14 ◽  
pp. 361-361
Author(s):  
Stephen Warren ◽  
Susan Frankenstein
Keyword(s):  
Vapor Pressure ◽  
Sea Level ◽  
Ice Sheet ◽  
Crystal Formation ◽  
Climatic Warming ◽  
Saturation Vapor Pressure ◽  
Simple Assumption ◽  
Near Surface ◽  
The Antarctic ◽  
Saturation Vapor

Climatic warming due to increased greenhouse gases is expected to cause increased precipitation in the next century because of the increased water content of the air, assuming constant relative humidity. Since temperatures over most of Antarctica are far below freezing even in the warmest month of the year, the increase in melting is probably negligible compared to the increase in precipitation.Oerlemans (1982) showed that this increase of precipitation would cause a growth of the ice sheet, tending to lower sea level. This would partially counteract the rise of sea level due to increased melting on mountain glaciers and Greenland, and to a possible (and more difficult to predict) surge of ice from West Antarctica.Oerlemans may have underestimated the increase in accumulation. He used results of General Circulation Models (GCMs) which indicated an increase of precipitation by only 12% for a temperature change ΔΤ = 3 Κ and 30% for ΔΤ = 8 K. In contrast, the change in accumulation rate at Dome C (Lorius and others, 1979) accompanying the warming from the recent ice age to the present was in accord with the simple assumption that accumulation is proportional to saturation vapor pressure at the temperature of the inversion layer, i.e. a 30% increase for ΔΤ = 3 K.The experimental results are to be preferred to the climate model results because GCMs do not represent ice-sheet accumulation processes well. Most of the accumulation is not snow falling from clouds but instead results from clear-sky ice-crystal formation in near-surface air, or hoarfrost deposition on the surface. GCMs lack sufficient vertical resolution to represent the strong temperature inversion on which these accumulation mechanisms depend.The figure shows that the increase of vapor pressure due to ΔΤ = 5 Κ varies from a factor of 1.9 at Τ = −60°C to a factor of 1.6 at Τ = −20°C. A climatic warming of 5 K. over Antarctica, which is possible during the next century, could thus increase the Antarctic accumulation from its present 17g cm−2 yr−1 to 30 g cm−2 yr−1, leading to a 50 cm drop in sea level in 100 years. This assumes that the simple proportionality of precipitation rate to saturation vapor pressure applies as well to the coastal regions, which is doubtful because the accumulation processes are not the same as on the plateau.The potential importance of Antarctic accumulation changes in contributing to changes of sea level argues for further study of the mechanisms of Antarctic precipitation and for their improved representation in climate models.

scholarly journals Increased Accumulation On The Antarctic Ice Sheet Due To Climatic Warming

1990 ◽  
Vol 14 ◽  
pp. 361
Author(s):  
Stephen Warren ◽  
Susan Frankenstein
Keyword(s):  
Vapor Pressure ◽  
Sea Level ◽  
Ice Sheet ◽  
Crystal Formation ◽  
Climatic Warming ◽  
Saturation Vapor Pressure ◽  
Simple Assumption ◽  
Near Surface ◽  
The Antarctic ◽  
Saturation Vapor

Climatic warming due to increased greenhouse gases is expected to cause increased precipitation in the next century because of the increased water content of the air, assuming constant relative humidity. Since temperatures over most of Antarctica are far below freezing even in the warmest month of the year, the increase in melting is probably negligible compared to the increase in precipitation. Oerlemans (1982) showed that this increase of precipitation would cause a growth of the ice sheet, tending to lower sea level. This would partially counteract the rise of sea level due to increased melting on mountain glaciers and Greenland, and to a possible (and more difficult to predict) surge of ice from West Antarctica. Oerlemans may have underestimated the increase in accumulation. He used results of General Circulation Models (GCMs) which indicated an increase of precipitation by only 12% for a temperature change ΔΤ = 3 Κ and 30% for ΔΤ = 8 K. In contrast, the change in accumulation rate at Dome C (Lorius and others, 1979) accompanying the warming from the recent ice age to the present was in accord with the simple assumption that accumulation is proportional to saturation vapor pressure at the temperature of the inversion layer, i.e. a 30% increase for ΔΤ = 3 K. The experimental results are to be preferred to the climate model results because GCMs do not represent ice-sheet accumulation processes well. Most of the accumulation is not snow falling from clouds but instead results from clear-sky ice-crystal formation in near-surface air, or hoarfrost deposition on the surface. GCMs lack sufficient vertical resolution to represent the strong temperature inversion on which these accumulation mechanisms depend. The figure shows that the increase of vapor pressure due to ΔΤ = 5 Κ varies from a factor of 1.9 at Τ = −60°C to a factor of 1.6 at Τ = −20°C. A climatic warming of 5 K. over Antarctica, which is possible during the next century, could thus increase the Antarctic accumulation from its present 17g cm−2 yr−1 to 30 g cm−2 yr−1, leading to a 50 cm drop in sea level in 100 years. This assumes that the simple proportionality of precipitation rate to saturation vapor pressure applies as well to the coastal regions, which is doubtful because the accumulation processes are not the same as on the plateau. The potential importance of Antarctic accumulation changes in contributing to changes of sea level argues for further study of the mechanisms of Antarctic precipitation and for their improved representation in climate models.

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