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57. Oxygen dissociation pressures over uranium oxides.
276
Abstracts 56---70
17 56. A Mass Spectrometric Study of the Vaporization of Ferrous Bromide. United States. A mass spectrometer has been used to analyze the vapors effusing from a Knudsen cell containing FeBr2(s). In the temperature interval 62ff-665°K, the monomer is the predominant vapor species ; but at the melting point the dirner concentration becomes significant. Thermochernical data have been determined for the r e a c t i o n s : 2 F e B r 2 ( s ) : Fe2Br4(g), AH°~40 : 59.5 ± kcal./mole dimer ; Fe2Br~(g) : 2FeBr2(g), AH%4o : 34.7 ± 4 kcal./mole dirner. (Author) Richard F. Porter and Richard C. Schoonrnaker, J. Phys. Chem., 63, 626-628, April 1959. 17 57. Oxygen Dissociation Pressures Over Uranium Oxides. United States. Oxygen dissociation pressures over the uranium oxides, UOz.0 to UO2.e, were measured between 950 and 1150 ° by the Knudsen effusion method. In this temperature and composition range there are three stable uranium oxides : UO2 in which the solubility of oxygen increases with temperature, U409 with a narrow homogeneity range, and U5013 in which oxygen dissolves. A phase diagram of the uranium-oxygen system was constructed and thermodynamics values were derived. (Author) P. E. Blackburn, J. Phys. Chem., 62, 89%902, Aug. 1958. 17 : 34 58. High-Altitude Atmospheric Density. United States. Atmospheric density values obtained from the motion of artificial earth satellites, at altitudes between 186 and 656 kilometers, are discussed. There is some doubt about the reliability of densities from satellites because of the effects of ionization and, in the case of nonspherical satellites, because of their orientation. Densities inferred from satellites are higher than for the A R D C model of the atmosphere. These densities are about ten times higher than densities inferred from rocketborne ionization gauges between 186 and 230 kin. The inference of atmospheric density from rocket-borne ionization gauges is discussed critically, and densities so obtained are considered to be inferior in reliability to the satellite densities. The satellite densities suggest molecular scale temperatures higher than those of the A R D C model in one or more regions of altitude above 80 krn. Theodore E. Sterne, Physics of Fluids, 1,165-171, May-June 1958. 17:34 59. Comparison of High-Altitude Rocket and Satellite Density Measurements. United States. Atmospheric density measurements obtained with rocket-borne ionization gauges are compared with U.S.A. and U.S.S.R. satellite-drag density measurements. There is no significant disagreement between the results obtained by the two methods once atmospheric variations are taken into account. H. E. LaGow and R. Horowitz, Physics of Fluids, 1, 478 479, Nov.-Dec. 1958. 17 60. Approximate Formula for the Thermal Conductivity of Gas Mixtures. United States. An approximate formula for the thermal conductivity of multi-component gas mixtures is derived from rigorous kinetic theory by well-defined approximations. Numerical calculations with the formula are relatively simple, and the only data needed are the molecular weights, thermal conductivities, and either viscosities or heat capacities of the pure components at the same temperature as the mixture. The form of the formula is quite similar to the earlier empirical LindsayBromley equation. The formula is tested by comparison with experimental results on a number of binarY and ternary mixtures
involving both rnonatomic and polatomic nonpolar gases. Agreement is satisfactory, and is nearly as good as obtained with the full rigorous theory. E. A. Mason and S. C. Saxena, Physics of Fluids, 1, 361-370, Sept.-Oct. 1958. 17:47 61. Dissociation Pressure and Stability of Beryllium Carbide. United States, Equilibrium pressures for the reaction 1/2Be2C(s) = B e ( g ) ÷ l/2C(s) were measured in the temperature range 1430-1669°K, by the Knudsen technique. The dissociation pressure in this temperature range is given by the equation log P (atrn) = 7.026 ÷ 0.347-(19, 720 ÷ 537)/T. The heat and free energy of formation of beryllium carbide were derived from the above equation in combination with the literature vapor pressure data for solid beryllium. (Author) B. D. Pollock, J. Phys. Chem., 63, 587-589, April 1959. 17 62. Kinetic Theory of Moderately Dense Gases. R. F. Snider and C. F. Curtiss, Physics of Fluids, 1, 122-139, March-April 1958. 17 63. Condensation of an Imperfect Buson Gas. Robert H. Kraichnan, Physics of Fluids, 2, 463-466, July-August 1959. 17:47 64. The Vaporization of Molybdenum and Tungsten Oxides. P. E. Blackburn, M. Hoch and H. L. Johnston, J. Phys. Chem., 62, 769-773, July 1958. 17 65. Applicability of the Knudsen Effusion Method to the Study of Decomposition Reactions. The Decomposition of Magnesium Hydroxide. E. Kay and 1'4. W. Gregory, J. Phys. Chem., 62, 1079-1083, Sept. 1958. 17 : 18 66. Thermodynamics of Electrically Conducting Fluids. Boa-Teh Chu, Physics of Fluids, 2, 473-485, Sept.-Oct. 1959. 17 67. Compressibility and Intermolecular Forces in Gases : Methane. H. W. Schamp, Jr., E. A. Mason, A. C. B. Richardson, and A. Altrnan, Physics of Fluids, 1, 329-338, July-Aug. 1958. 17:30 68. Evaporation into a Boundary Layer. Ernest Bauer and Martin Zlotnick, Physics of Fluids, 1, 355-357, July-Aug. 1958. 17 69. Heat Transfer to a Sphere at the Transition from Free Molecule Flow. Letter by P. Hammerling and B. Kivel, Physics of Fluids, 1, 357, July-Aug. 1958. Evaporation into a Boundary Layer. Evaporation. See Abstract No. 10.
18.
17 : 15 : 30 II. Dissociation in
Gaseous Electronics
18 70. Electron Acceleration against an Opposing Field in a Vacuum Electromagnetic Discharge. Letter by Joseph Slepian, Physics of Fluids, 1, 547, Nov.-Dec. 1958.
Abstracts 56---70
17 56. A Mass Spectrometric Study of the Vaporization of Ferrous Bromide. United States. A mass spectrometer has been used to analyze the vapors effusing from a Knudsen cell containing FeBr2(s). In the temperature interval 62ff-665°K, the monomer is the predominant vapor species ; but at the melting point the dirner concentration becomes significant. Thermochernical data have been determined for the r e a c t i o n s : 2 F e B r 2 ( s ) : Fe2Br4(g), AH°~40 : 59.5 ± kcal./mole dimer ; Fe2Br~(g) : 2FeBr2(g), AH%4o : 34.7 ± 4 kcal./mole dirner. (Author) Richard F. Porter and Richard C. Schoonrnaker, J. Phys. Chem., 63, 626-628, April 1959. 17 57. Oxygen Dissociation Pressures Over Uranium Oxides. United States. Oxygen dissociation pressures over the uranium oxides, UOz.0 to UO2.e, were measured between 950 and 1150 ° by the Knudsen effusion method. In this temperature and composition range there are three stable uranium oxides : UO2 in which the solubility of oxygen increases with temperature, U409 with a narrow homogeneity range, and U5013 in which oxygen dissolves. A phase diagram of the uranium-oxygen system was constructed and thermodynamics values were derived. (Author) P. E. Blackburn, J. Phys. Chem., 62, 89%902, Aug. 1958. 17 : 34 58. High-Altitude Atmospheric Density. United States. Atmospheric density values obtained from the motion of artificial earth satellites, at altitudes between 186 and 656 kilometers, are discussed. There is some doubt about the reliability of densities from satellites because of the effects of ionization and, in the case of nonspherical satellites, because of their orientation. Densities inferred from satellites are higher than for the A R D C model of the atmosphere. These densities are about ten times higher than densities inferred from rocketborne ionization gauges between 186 and 230 kin. The inference of atmospheric density from rocket-borne ionization gauges is discussed critically, and densities so obtained are considered to be inferior in reliability to the satellite densities. The satellite densities suggest molecular scale temperatures higher than those of the A R D C model in one or more regions of altitude above 80 krn. Theodore E. Sterne, Physics of Fluids, 1,165-171, May-June 1958. 17:34 59. Comparison of High-Altitude Rocket and Satellite Density Measurements. United States. Atmospheric density measurements obtained with rocket-borne ionization gauges are compared with U.S.A. and U.S.S.R. satellite-drag density measurements. There is no significant disagreement between the results obtained by the two methods once atmospheric variations are taken into account. H. E. LaGow and R. Horowitz, Physics of Fluids, 1, 478 479, Nov.-Dec. 1958. 17 60. Approximate Formula for the Thermal Conductivity of Gas Mixtures. United States. An approximate formula for the thermal conductivity of multi-component gas mixtures is derived from rigorous kinetic theory by well-defined approximations. Numerical calculations with the formula are relatively simple, and the only data needed are the molecular weights, thermal conductivities, and either viscosities or heat capacities of the pure components at the same temperature as the mixture. The form of the formula is quite similar to the earlier empirical LindsayBromley equation. The formula is tested by comparison with experimental results on a number of binarY and ternary mixtures
involving both rnonatomic and polatomic nonpolar gases. Agreement is satisfactory, and is nearly as good as obtained with the full rigorous theory. E. A. Mason and S. C. Saxena, Physics of Fluids, 1, 361-370, Sept.-Oct. 1958. 17:47 61. Dissociation Pressure and Stability of Beryllium Carbide. United States, Equilibrium pressures for the reaction 1/2Be2C(s) = B e ( g ) ÷ l/2C(s) were measured in the temperature range 1430-1669°K, by the Knudsen technique. The dissociation pressure in this temperature range is given by the equation log P (atrn) = 7.026 ÷ 0.347-(19, 720 ÷ 537)/T. The heat and free energy of formation of beryllium carbide were derived from the above equation in combination with the literature vapor pressure data for solid beryllium. (Author) B. D. Pollock, J. Phys. Chem., 63, 587-589, April 1959. 17 62. Kinetic Theory of Moderately Dense Gases. R. F. Snider and C. F. Curtiss, Physics of Fluids, 1, 122-139, March-April 1958. 17 63. Condensation of an Imperfect Buson Gas. Robert H. Kraichnan, Physics of Fluids, 2, 463-466, July-August 1959. 17:47 64. The Vaporization of Molybdenum and Tungsten Oxides. P. E. Blackburn, M. Hoch and H. L. Johnston, J. Phys. Chem., 62, 769-773, July 1958. 17 65. Applicability of the Knudsen Effusion Method to the Study of Decomposition Reactions. The Decomposition of Magnesium Hydroxide. E. Kay and 1'4. W. Gregory, J. Phys. Chem., 62, 1079-1083, Sept. 1958. 17 : 18 66. Thermodynamics of Electrically Conducting Fluids. Boa-Teh Chu, Physics of Fluids, 2, 473-485, Sept.-Oct. 1959. 17 67. Compressibility and Intermolecular Forces in Gases : Methane. H. W. Schamp, Jr., E. A. Mason, A. C. B. Richardson, and A. Altrnan, Physics of Fluids, 1, 329-338, July-Aug. 1958. 17:30 68. Evaporation into a Boundary Layer. Ernest Bauer and Martin Zlotnick, Physics of Fluids, 1, 355-357, July-Aug. 1958. 17 69. Heat Transfer to a Sphere at the Transition from Free Molecule Flow. Letter by P. Hammerling and B. Kivel, Physics of Fluids, 1, 357, July-Aug. 1958. Evaporation into a Boundary Layer. Evaporation. See Abstract No. 10.
18.
17 : 15 : 30 II. Dissociation in
Gaseous Electronics
18 70. Electron Acceleration against an Opposing Field in a Vacuum Electromagnetic Discharge. Letter by Joseph Slepian, Physics of Fluids, 1, 547, Nov.-Dec. 1958.