The CH3+NO rate coefficient at high temperatures: Theoretical analysis and comparison with experiment

Flat surfaces and grain boundaries lying on low crystal planes are singular corresponding to the cusps in the polar (Wulff) plots of their energy against their orientation. The theoretical analysis of the entropy effect at high temperatures shows that these interfaces undergo roughening transitions. The molecular dynamics simulations also show disordering to liquid-like structures at high temperatures that can be interpreted as the roughening transition. Experimentally, singular flat surfaces and grain boundaries become curved at high temperatures or with additives, indicating their roughening transition. The grain boundaries in polycrystals are often faceted with hill-and-valley shapes and their defaceting at high temperatures also show their roughening transition.

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Inlet Shear Heating in Elastohydrodynamic Lubrication

Journal of Lubrication Technology ◽

10.1115/1.3451844 ◽

1973 ◽

Vol 95 (4) ◽

pp. 417-423 ◽

Cited By ~ 44

Author(s):

J. A. Greenwood ◽

J. J. Kauzlarich

Keyword(s):

Shear Rate ◽

Theoretical Analysis ◽

Film Thickness ◽

Temperature Rise ◽

Thermal Effects ◽

Elastohydrodynamic Lubrication ◽

Oil Film ◽

Comparison With Experiment ◽

Pure Rolling ◽

Shear Heating

In EHL, the oil film thickness of rollers is controlled by the rate at which the oil is drawn into the conjunction of the disks by the moving surfaces of the rollers. The theory often assumes isothermal conditions in the inlet although it can be shown that the maximum shear rate often exceeds 106 sec−1, even in pure rolling. A theoretical analysis is presented for the oil temperature rise in the inlet of rollers, and the result is applied to predict the consequent film thickness. It is found that thermal effects on film thickness are only negligible at low rolling speeds. A comparison with experiment supports the conclusion that the thinning of the film thickness below that predicted by isothermal theory is substantially explained by inlet shear heating of the lubricant.

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Rate coefficient for the reaction H+O2→OH+O: Results at high temperatures, 2000 to 5300 K

The Journal of Chemical Physics ◽

10.1063/1.462194 ◽

1992 ◽

Vol 96 (2) ◽

pp. 1077-1092 ◽

Cited By ~ 76

Author(s):

Hong Du ◽

Jan P. Hessler

Keyword(s):

High Temperatures ◽

Rate Coefficient

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Trajectory study of dissociation reactions. Br2 in Ar at 3500 K

Canadian Journal of Chemistry ◽

10.1139/v77-058 ◽

1977 ◽

Vol 55 (3) ◽

pp. 380-382 ◽

Cited By ~ 7

Author(s):

D. T. Chang ◽

George Burns

Keyword(s):

High Temperatures ◽

Rate Constant ◽

Rate Coefficient ◽

Dissociation Rate ◽

Experimental Results ◽

Dissociation Rate Constant ◽

Trajectory Calculations ◽

Order Of Magnitude ◽

Nonequilibrium Effects ◽

The One

Dissociation of Br2 in Ar was studied at 3500 K using classical 3-D trajectory technique, and compared with earlier trajectory calculations. Some of the assumptions used previously were eliminated, while others were studied in some detail. The one-way flux, equilibrium rate coefficient, obtained from over 8400 trajectories, was found to be over an order of magnitude larger than the experimental rate constant. This was taken as an indication that at high temperatures the nonequilibrium effects are important in dissociation reactions. In order to understand these effects better, additional calculations using an improved set of assumptions were performed. The calculated dissociation rate constant for Br2 + Ar → 2Br + Ar reaction, which accounted for nonequilibrium effects, agrees reasonably well with experimental results.

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