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658.Measuring pressures below 10−3 mm Hg with a compensated mercury manometer
Classified Abstracts
658-665
Classified Abstracting
Abstracts
Editor’s Note. The label immediately foIIowing the title of each item denotes country of origin of publication, and that at the end of each abstract indicates country of origin of work (where known). General
12.
Vacuum
Science
12 658. Measuring pressures below 10e3 mm Hg with a compensated mercury manometer. (U.S.S.R.) A. V. Eryukhin, Measurement Tech., (6), Dec. 1962, 466-471 ; translated from the Russian in Zzmerit. Tekhnika, (6), June 1962, 16-20.
J. T. Clarke, J. Phys. Chem., 68, April 1964, 884-888. 16 664. Application of flash-desorption method to catalyst studies. IV. Adsorption of ammonia on alumina and its effect on adsorption of ethylene. (U.S. A.) Adsorption of ammonia on an alumina catalyst and its effect on the subsequent adsorption of ethylene have been studied by the flash-desorption method. It has been found that the activation energy of desorption of ammonia increases from 7 to 18 kcal/mole as the surface coverage decreases from 29 to 1.5 per cent. A large excess of ammonia, preadsorbed at 250”, has to be used in order to block the active sites for the strong adsorption of ethylene. When the temperature at which ammonia is preadsorbed is varied between 175 and 900”, the amount of the strongly adsorbed ethylene goes through a minimum (in the neighbourhood of 500”). From these results it is concluded that the active sites for ethylene adsorption do not coincide with the highest energy sites for ammonia desorption, although they are within the distribution range of ammonia. (U.S.A.) (Author) Y. Amenomiya et al., .I. Phys. Chem., 68, Jan. 1964, 52-57.
12 659. Ultra-high vacuum instrumentation. (U.S. A.) T. A. Vanderslice, Science, 112, (3589), 11 Oct. 1963, 178-184.
660. Absolute gas pressure measurement and regulation near 1 to:r: (U.S.A.) T. H. Jeong and L. H. Johnston, Nuclear Znstrum & Meth., 25 (2), Jan. 1964,221-223.
Kinetic Theory of Gases
14 661. Effect of “ rougher-than-rough ” surfaces on molecular flow through short ducts. (U.S.A.) D. G. Davis et al., J. Appl. Phys., 35 (3), March 1964, 529-532.
15.
16 665. Chemisorption of amines and its effect on subsequent oxidation of iron surfaces. (U.S.A.) The adsorption of amines and the oxidation of clean and amine prechemisorbed reduced iron surfaces were measured using continuous flowing gas mass spectrometry. The amines used include n-butylamine, n-hexylamine, t-butylamine, cyclohexylamine, pyrrolidine, piperidine, and pyridine. It is shown that although the amines are good inhibitors for corrosion in water solution, they are relatively poor inhibitors for oxidation of iron in a dry atmosphere. The total oxygen uptake by iron surfaces covered with the chemisorbed amines decreases from 95 per cent of that for the amine-free surface to 62 per cent of that for the amine-free surface as the ionization potential of the amines decreases. A tentative explanation of this effect based on the change of contact potential due to chemisorption and the Cabrera and Mott theory of thin oxide film growth is offered. The mass spectra of the gas stream leaving the sample during adsorption and desorption were examined. Deuterium exchange experiments were also conducted. The results show that the chemisorption of amine on the reduced and oxidized iron surface is essentially nondissociative. An amount corresponding to monolayer coverage was chemisorbed on the surfaces for all the amines studied except t-butylamine, for which the chemisorption was weaker and the amount adsorbed less. Oxidation of an iron surface covered with chemisorbed amine does not desorb the chemisorbed amines. The amine does not react with the oxygen but is left chemisorbed on the iron oxide surface. (U.S.A.) (Author) Yung-Fang Yu Yao, J. Phvs. Chem., 68, Jan. 1964, 101-105.
Fluid Dynamics
15 662. One-dimensional unsteady flow of a gas in the presence of ionizing radiations. General equations. (Italy) C. Ferrari and J. H. Clarke, RC Accad. Naz. Lincei, (Italy), 35, July-Aug. 1963, 1-2, 3-9.
16.
Engineering
area results primarily from the opening of closed ..ores ; this allows one to estimate the surface area of graphite samples (Author) having different sizes and shapes.
Measurement of Low Pressures
14.
and
Gases and Solids
16 663. Surface area measurement of graphite using the y radiation of Kr. (U.S.A.) A method developed to measure the surface area of small samples of low surface area materials using the y radiation of Krss traced Kr to determine the amount of Kr adsorbed. Since the count rate observed is directly proportional to the Kr adsorbed, the method is much more rapid and the calculations much less time-consuming than other methods of surface area measurement. The method is applicable over a wide range of surface areas (0.001 to 10 m”/g) and to sample sizes of 0.5 g or less. The long half-life of Kre5 (10.4 years) minimizes the corrections necessary for radioactive decay. The usual advantages of Kr over nitrogen (inertness, low vapor phase corrections, and spherical shape) are utilized in this method. Using this new method, it was found that the surface area of TSZ nuclear graphite increased by a factor of four as the particle size was reduced from 3 mm cubes to 80 mesh. This is interpreted as indicating that the increased surface 281
658-665
Classified Abstracting
Abstracts
Editor’s Note. The label immediately foIIowing the title of each item denotes country of origin of publication, and that at the end of each abstract indicates country of origin of work (where known). General
12.
Vacuum
Science
12 658. Measuring pressures below 10e3 mm Hg with a compensated mercury manometer. (U.S.S.R.) A. V. Eryukhin, Measurement Tech., (6), Dec. 1962, 466-471 ; translated from the Russian in Zzmerit. Tekhnika, (6), June 1962, 16-20.
J. T. Clarke, J. Phys. Chem., 68, April 1964, 884-888. 16 664. Application of flash-desorption method to catalyst studies. IV. Adsorption of ammonia on alumina and its effect on adsorption of ethylene. (U.S. A.) Adsorption of ammonia on an alumina catalyst and its effect on the subsequent adsorption of ethylene have been studied by the flash-desorption method. It has been found that the activation energy of desorption of ammonia increases from 7 to 18 kcal/mole as the surface coverage decreases from 29 to 1.5 per cent. A large excess of ammonia, preadsorbed at 250”, has to be used in order to block the active sites for the strong adsorption of ethylene. When the temperature at which ammonia is preadsorbed is varied between 175 and 900”, the amount of the strongly adsorbed ethylene goes through a minimum (in the neighbourhood of 500”). From these results it is concluded that the active sites for ethylene adsorption do not coincide with the highest energy sites for ammonia desorption, although they are within the distribution range of ammonia. (U.S.A.) (Author) Y. Amenomiya et al., .I. Phys. Chem., 68, Jan. 1964, 52-57.
12 659. Ultra-high vacuum instrumentation. (U.S. A.) T. A. Vanderslice, Science, 112, (3589), 11 Oct. 1963, 178-184.
660. Absolute gas pressure measurement and regulation near 1 to:r: (U.S.A.) T. H. Jeong and L. H. Johnston, Nuclear Znstrum & Meth., 25 (2), Jan. 1964,221-223.
Kinetic Theory of Gases
14 661. Effect of “ rougher-than-rough ” surfaces on molecular flow through short ducts. (U.S.A.) D. G. Davis et al., J. Appl. Phys., 35 (3), March 1964, 529-532.
15.
16 665. Chemisorption of amines and its effect on subsequent oxidation of iron surfaces. (U.S.A.) The adsorption of amines and the oxidation of clean and amine prechemisorbed reduced iron surfaces were measured using continuous flowing gas mass spectrometry. The amines used include n-butylamine, n-hexylamine, t-butylamine, cyclohexylamine, pyrrolidine, piperidine, and pyridine. It is shown that although the amines are good inhibitors for corrosion in water solution, they are relatively poor inhibitors for oxidation of iron in a dry atmosphere. The total oxygen uptake by iron surfaces covered with the chemisorbed amines decreases from 95 per cent of that for the amine-free surface to 62 per cent of that for the amine-free surface as the ionization potential of the amines decreases. A tentative explanation of this effect based on the change of contact potential due to chemisorption and the Cabrera and Mott theory of thin oxide film growth is offered. The mass spectra of the gas stream leaving the sample during adsorption and desorption were examined. Deuterium exchange experiments were also conducted. The results show that the chemisorption of amine on the reduced and oxidized iron surface is essentially nondissociative. An amount corresponding to monolayer coverage was chemisorbed on the surfaces for all the amines studied except t-butylamine, for which the chemisorption was weaker and the amount adsorbed less. Oxidation of an iron surface covered with chemisorbed amine does not desorb the chemisorbed amines. The amine does not react with the oxygen but is left chemisorbed on the iron oxide surface. (U.S.A.) (Author) Yung-Fang Yu Yao, J. Phvs. Chem., 68, Jan. 1964, 101-105.
Fluid Dynamics
15 662. One-dimensional unsteady flow of a gas in the presence of ionizing radiations. General equations. (Italy) C. Ferrari and J. H. Clarke, RC Accad. Naz. Lincei, (Italy), 35, July-Aug. 1963, 1-2, 3-9.
16.
Engineering
area results primarily from the opening of closed ..ores ; this allows one to estimate the surface area of graphite samples (Author) having different sizes and shapes.
Measurement of Low Pressures
14.
and
Gases and Solids
16 663. Surface area measurement of graphite using the y radiation of Kr. (U.S.A.) A method developed to measure the surface area of small samples of low surface area materials using the y radiation of Krss traced Kr to determine the amount of Kr adsorbed. Since the count rate observed is directly proportional to the Kr adsorbed, the method is much more rapid and the calculations much less time-consuming than other methods of surface area measurement. The method is applicable over a wide range of surface areas (0.001 to 10 m”/g) and to sample sizes of 0.5 g or less. The long half-life of Kre5 (10.4 years) minimizes the corrections necessary for radioactive decay. The usual advantages of Kr over nitrogen (inertness, low vapor phase corrections, and spherical shape) are utilized in this method. Using this new method, it was found that the surface area of TSZ nuclear graphite increased by a factor of four as the particle size was reduced from 3 mm cubes to 80 mesh. This is interpreted as indicating that the increased surface 281