CH(A2Δ) Formation in Hydrocarbon Combustion:  The Temperature Dependence of the Rate Constant of the Reaction C2H + O2→ CH(A2Δ) + CO2

2005 ◽  
Vol 109 (45) ◽  
pp. 10287-10293 ◽  
Author(s):  
Rehab M. I. Elsamra ◽  
Stijn Vranckx ◽  
Shaun A. Carl
Keyword(s):  
Temperature Dependence ◽  
Rate Constant ◽  
Hydrocarbon Combustion

Radiolysis studies on the corrosion inhibitors 1 -hexyn-3-ol, cinnamonitrile, and 1,3-diethyl-2-thiourea

1995 ◽  
Vol 73 (12) ◽  
pp. 2137-2142 ◽  
Author(s):  
A.J. Elliot ◽  
M.P. Chenier ◽  
D.C. Ouellette
Keyword(s):  
Hydrogen Atom ◽  
Hydroxyl Radical ◽  
Temperature Dependence ◽  
Rate Constant ◽  
Rate Constants ◽  
Corrosion Inhibitors ◽  
Hydrated Electron

In this publication we report: (i) the rate constants for reaction of the hydrated electron with 1-hexyn-3-ol ((8.6 ± 0.3) × 108 dm3 mol−1 s−1 at 18 °C), cinnamonitrile ((2.3 ± 0.2) × 1010 dm3 mol−1 s−1 at 20 °C), and 1,3-diethyl-2-thiourea ((3.5 ± 0.3) × 108 dm3 mol−1 s−1 at 22 °C). For cinnamonitrile and diethylthiourea, the temperature dependence up to 200 °C and 150 °C, respectively, is also reported; (ii) the rate constants for the reaction of the hydroxyl radical with 1-hexyn-3-ol ((5.5 ± 0.5) × 109 dm3 mol−1 s−1 at 20 °C), cinnamonitrile ((9.2 ± 0.3) × 109 dm3 mol−1 s−1 at 21 °C), and diethylthiourea ((8.0 ± 0.8) × 108 dm3 mol−1 s−1 at 22 °C). For cinnamonitrile, the temperature dependence up to 200 °C is also reported; (iii) the rate constant for the hydrogen atom reacting with 1-hexyn-3-ol ((4.3 ± 0.4) × 109 dm3 mol−1 s−1 at 20 °C). Keywords: radiolysis, corrosion inhibitors, rate constants.

Temperature dependence of the O+I(P21/2)→O+I(P23/2) quenching rate constant

2009 ◽  
Vol 105 (9) ◽  
pp. 094911 ◽  
Author(s):  
Pavel A. Mikheyev ◽  
David J. Postell ◽  
Michael C. Heaven
Keyword(s):  
Temperature Dependence ◽  
Rate Constant ◽  
Quenching Rate ◽  
Quenching Rate Constant

Radiolysis of Supercritical Water at 400°C: A Sensitivity Study of the Density Dependence of the Yield of Hydrated Electrons on the (eaq−+eaq−) Reaction Rate Constant

2016 ◽  
Vol 2 (2) ◽  
Author(s):  
Sunuchakan Sanguanmith ◽  
Jintana Meesungnoen ◽  
David A. Guzonas ◽  
Craig R. Stuart ◽  
Jean-Paul Jay-Gerin
Keyword(s):  
Temperature Dependence ◽  
Density Dependence ◽  
Rate Constant ◽  
Supercritical Water ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Sudden Drop ◽  
Alkaline Water ◽  
Hydrated Electrons ◽  
Neutral Water

The temperature dependence of the rate constant (k) of the bimolecular reaction of two hydrated electrons (eaq−) measured in alkaline water exhibits an abrupt drop between 150°C and 200°C; above 250°C, it is too small to be measured reliably. Although this result is well established, the applicability of this sudden drop in k(eaq−+eaq−)) above ∼150°C to neutral or slightly acidic solution, as recommended by some authors, still remains uncertain. In fact, the recent work suggested that in near-neutral water the abrupt change in k above ∼150°C does not occur and that k should increase, rather than decrease, at temperatures greater than 150°C with roughly the same Arrhenius dependence of the data below 150°C. In view of this uncertainty of k, Monte Carlo simulations were used in this study to examine the sensitivity of the density dependence of the yield of eaq− in the low–linear energy transfer (LET) radiolysis of supercritical water (H2O) at 400°C on variations in the temperature dependence of k. Two different values of the eaq− self-reaction rate constant at 400°C were used: one was based on the temperature dependence of k above 150°C as measured in alkaline water (4.2×108  M−1 s−1), and the other was based on an Arrhenius extrapolation of the values below 150°C (2.5×1011  M−1 s−1). In both cases, the density dependences of our calculated eaq− yields at ∼60  ps and 1 ns were found to compare fairly well with the available picosecond pulse radiolysis experimental data (for D2O) for the entire water density range studied (∼0.15–0.6  g/cm3). Only a small effect of k on the variation of G(eaq−)) as a function of density at 60 ps and 1 ns could be observed. In conclusion, our present calculations did not allow us to unambiguously confirm (or deny) the applicability of the predicted sudden drop of k(eaq−+eaq−) at ∼150°C in near-neutral water.

scholarly journals Differential Scanning Calorimetry of Metamict Pu-Substituted Zirconolite

1982 ◽  
Vol 15 ◽  
Author(s):  
Dean E. Peterson ◽  
Frank W. Clinard
Keyword(s):  
Activation Energy ◽  
Differential Scanning Calorimetry ◽  
Ambient Temperature ◽  
Total Energy ◽  
Temperature Dependence ◽  
Radiation Damage ◽  
Rate Constant ◽  
Stored Energy ◽  
Scanning Calorimetry ◽  
No Release

ABSTRACTSamples of CaPuTi2O7 were prepared by cold pressing and sintering. Plutonium was substituted for zirconium in order to characterize radiation damage effects. The energy stored in a sample which had reached saturation in swelling after storage at ambient temperature was measured with a differential scanning calorimeter. The total energy of 6.6±0.1 cal/g is released over the range 485–715° C. The activation energy of annealing of the damage is 1.22±0.05 eV. The temperature dependence of the rate constant is described by kT= 5.96E4 exp(−1.22/kBT) s−1 where kB and T are the Boltzmann's constant and temperature(K) respectively. A sample stored at 600°C was similarly evaluated and showed no release of stored energy to the precision of the apparatus (±0.1 cal/g). These results are applied to analysis of waste incorporation in Synroc and are correlated with analogous parameters for other materials.

scholarly journals Reversible conformational transition gives rise to 'zig-zag' temperature dependence of the rate constant of irreversible thermoinactivation of enzymes

1994 ◽  
Vol 219 (1-2) ◽  
pp. 219-230 ◽  
Author(s):  
Vladislav Yu. LEVITSKY ◽  
Nikolay S. MELIK-NUBAROV ◽  
Virginius A. SIKSNIS ◽  
Valeriy Ya. GRINBERG ◽  
Tatyana V. BUROVA ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Rate Constant ◽  
Conformational Transition
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