Room-temperature rate constant for the hydroperoxo + hydroperoxo reaction at low pressures

1984 ◽  
Vol 88 (10) ◽  
pp. 2110-2116 ◽  
Author(s):  
Gerald A. Takacs ◽  
Carleton J. Howard
Keyword(s):  
Rate Constant ◽  
Room Temperature ◽  
Temperature Rate ◽  
Low Pressures

DYNAMICS OF THE N(2D)+H2 REACTION ON THE $\tilde{X}^2 A^{\prime\prime}$ SURFACE, PROPAGATING REAL WAVE PACKETS WITH AN ARCCOS MAPPING OF THE HAMILTONIAN

2003 ◽  
Vol 02 (04) ◽  
pp. 547-551 ◽  
Author(s):  
PAOLO DEFAZIO ◽  
CARLO PETRONGOLO
Keyword(s):  
Rate Constant ◽  
Cross Sections ◽  
Room Temperature ◽  
Wave Packets ◽  
Flux Analysis ◽  
Title Reaction ◽  
Angular Momentum Quantum Number ◽  
Insertion Mechanism ◽  
Temperature Rate ◽  
Good Agreement

We have investigated the dynamics of the title reaction with the Gray and Balint-Kurti approach, which propagates real wave packets (WP) under an arccos mapping of a scaled and shifted Hamiltonian. We have considered H 2 rotational quanta j=0 and 1 and obtained reaction probabilities using reactant coordinates and the flux analysis. We have calculated accurate reaction probabilities for total angular momentum quantum number J=0, centrifugal-sudden probabilities for J>0, cross sections, and the room temperature rate constant. The present cross sections are in good agreement with previous quasiclassical trajectory (QCT) results and the theoretical rate constant compares rather well with that observed. WP snapshots show that the reaction occurs via a C2v insertion mechanism, confirming previous QCT calculations.

Room temperature rate constant for H+F 2

2002 ◽  
Author(s):  
Jiande Han ◽  
Gerald C. Manke II ◽  
Michael C. Heaven
Keyword(s):  
Rate Constant ◽  
Room Temperature ◽  
Temperature Rate

Electron‐attachment rate constant for Cl2at room temperature and 250 °C

1979 ◽  
Vol 34 (3) ◽  
pp. 187-189 ◽  
Author(s):  
M. Rokni ◽  
J. H. Jacob ◽  
J. A. Mangano
Keyword(s):  
Rate Constant ◽  
Room Temperature ◽  
Electron Attachment ◽  
Attachment Rate

scholarly journals The catalytic combination of hydrogen and oxygen at the surface of platinum

1936 ◽  
Vol 156 (888) ◽  
pp. 284-306 ◽  
Keyword(s):  
Room Temperature ◽  
Quantitative Measurement ◽  
Silver Oxide ◽  
Catalytic Properties ◽  
Metallic Surface ◽  
Metallic Silver ◽  
Mercury Vapour ◽  
Platinum Surface ◽  
Gaseous Oxygen ◽  
Low Pressures

Research on the catalysis by metals of the combination of hydrogen and oxygen at low pressures was commenced in these laboratories by Cooper in 1923. Investigating the catalytic properties of a short platinum filament subjected to various pre-treatments by heating it electrically in hydrogen or oxygen or in vacuo , he found that the metallic surface thus cleaned became so active at room temperature as to render the quantitative measurement of the catalysed reaction impossible. It was discovered also that mercury vapour is a very potent poison of the surface, the enormously active clean platinum surface being rendered completely inactive by exposure to mercury vapour for a few minutes: a fact noted but apparently insufficiently emphasized in a paper published by Chapman and Hall in 1929. Owing to the difficulties involved in wording with a catalyst of such high activity, the research was discontinued in favour of an investigation of the same reaction using silver instead of platinum, a clean surface of this metal having been found to catalyse the reaction at a convenient rate at room temperature. The following facts were established:— (1) At the temperature of the laboratory a surface of metallic silver adsorbs completely a quantity of gaseous oxygen sufficient to form a complete unimolecular layer of silver oxide. This adsorbed oxygen cannot, of course, be removed by evacuation.

Surface analytical study of uranium exposed to low pressures of hydrogen at ∼ 80°C

2012 ◽  
Vol 1444 ◽  
Author(s):  
Robert M. Harker ◽  
Afiya H. Chohollo
Keyword(s):  
Room Temperature ◽  
Analytical Study ◽  
Treatment Cycle ◽  
X Ray Diffraction ◽  
Standard Samples ◽  
X Ray ◽  
Surface Precipitation ◽  
Pre Treatment ◽  
Low Pressures ◽  
Scanning Electron

ABSTRACTIdentical samples of uranium coupons were prepared and each exposed to hydrogen for different times (where this time is significantly less than a classically understood ‘induction time’). Samples were prepared from rolled depleted uranium stock: as-received oxide was removed on all surfaces and two faces (~12x12 mm) were polished to a sub-micron standard. Samples were individually taken through a Vacuum Thermal Pre-Treatment cycle from room temperature to 200°C to the reaction temperature (80°C) over 40 hours and subsequently exposed to 10 mbar O2 for 24 hours. After O2 was removed, the samples were exposed to hydrogen for pre-determined times of up to 48 minutes. Examination of the samples by Scanning Electron Microscopy (SEM) has, as expected, identified small features protruding from the surface believed to have been caused by sub-surface precipitation of UH3. In general these features are circular and isolated from each other, have a diameter of less than 3μm and appear as either ‘flat-topped’ or ‘domed’ morphology. In addition, longer time exposure samples show a predominance of ‘area attack’ where coalesced sub-surface precipitation appears to be confined to particular metal grains. X-Ray Diffraction (XRD) data show an increase in the quantity of UH3 with time.

Fatigue Crack Growth in SA508-CL2 Steel in a High Temperature, High Purity Water Environment

1974 ◽  
Vol 96 (4) ◽  
pp. 255-260 ◽  
Author(s):  
T. L. Gerber ◽  
J. D. Heald ◽  
E. Kiss
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
High Purity ◽  
Room Temperature ◽  
Water Environment ◽  
Cyclic Frequency ◽  
Asme Code ◽  
Temperature Rate

Fatigue crack growth tests were conducted with 1 in. (25.4 mm) plate specimens of SA508-CL2 steel in room temperature air, 550 deg F (288 deg C) air and in a 550 deg F (288 deg C), high purity, water environment. Zero-tension load controlled tests were run at cyclic frequencies as low as 0.037 CPM. Results show that growth rates in the simulated Boiling Water Reactor (BWR) water environment are 4 to 8 times faster than growth rates observed in 550 deg F (288 deg C) air and these rates are 8 to 15 times faster than the room temperature rate. In the BWR water environment, lowering the cyclic frequency from 0.37 CPM to 0.037 CPM caused only a slight increase in the fatigue crack growth rate. All growth rates measured in these tests were below the upper bound design curve presented in Section XI of the ASME Code.

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