The Combination Reaction of CH3 and C6H5O

1986 ◽  
Vol 39 (5) ◽  
pp. 723 ◽  
Author(s):  
CY Lin ◽  
CY Lin ◽  
MC Lin ◽  
MC Lin
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Shock Tube ◽  
Energy Barrier ◽  
Kinetic Modelling ◽  
Branching Ratios ◽  
Thermal Isomerization ◽  
Temperature Shock ◽  
Rrkm Theory ◽  
Butyl Peroxide

The kinetics and mechanism of the CH3+C6H5O reaction have been examined by means of the RRKM theory and kinetic modelling . Both the high temperature shock tube data for the production of cresols and the low temperature branching ratios (for production of cresols against methylcyclohexadienones , CH3C6H5O) derived from Mulcahy and Williams's data1 on the pyrolysis of di -t-butyl peroxide and phenol mixtures could be reasonably accounted for by the mechanism: ���������� CH3+C6H5O → CH3C6H5O → o- and p-CH3C6H4OH+M→ CH3C6H5OThe energy barrier for the thermal isomerization of CH3C6H5O to cresols was estimated to be ~ 132 kJ mol-1.

Early Experiments on Shock-Particle Interactions in the High-Temperature Shock Tube

2020 ◽  
Author(s):  
Samuel J. Petter ◽  
Kyle P. Lynch ◽  
Paul Farias ◽  
Seth Spitzer ◽  
Thomas Grasser ◽  
...  
Keyword(s):  
High Temperature ◽  
Shock Tube ◽  
Particle Interactions ◽  
Temperature Shock

Comparative High Temperature Shock Tube Ignition of C1−C4 Primary Alcohols

2010 ◽  
Vol 24 (11) ◽  
pp. 5834-5843 ◽  
Author(s):  
Khalid Emilio Noorani ◽  
Benjamin Akih-Kumgeh ◽  
Jeffrey M. Bergthorson
Keyword(s):  
High Temperature ◽  
Shock Tube ◽  
Primary Alcohols ◽  
Temperature Shock

High-Temperature Ignition Kinetics of Gas Turbine Lubricating Oils

2021 ◽  
Author(s):  
Sean P. Cooper ◽  
Eric L. Petersen
Keyword(s):  
Regression Analysis ◽  
High Temperature ◽  
Low Temperature ◽  
Shock Tube ◽  
Gas Turbine ◽  
Temperature Regime ◽  
Ignition Process ◽  
High Temperature Regime ◽  
Second Stage ◽  
Arrhenius Expression

Abstract Lubricant ignition is a highly undesirable event in any mechanical system, and surprisingly minimal work has been conducted to investigate the auto-ignition properties of gas turbine lubricants. To this end, using a recently established spray injection scheme in a shock tube, two gas turbine lubricants (Mobil DTE 732 and Lubricant A from Cooper et al. 2020) were subjected to high-temperature, post-reflected-shock conditions, and OH* chemiluminescence was monitored at the sidewall location of the shock tube to measure ignition delay time (τign). A combination of an extended shock-tube driver and driver-gas tailoring were utilized to observe ignition between 1183 K and 1385 K at near-atmospheric pressures. A clear, two-stage-ignition process was observed for all tests with Mobil DTE 732, and both first and second stage τign are compared. Second stage ignition was found to be more indicative of lubricant ignition and was used to compare τign values with lubricant A. Both lubricants exhibit three ignition regimes: a high-temperature, Arrhenius-like regime (> 1275 K); an intermediate, negative-temperature-coefficient-like regime (1230–1275 K); and a low-temperature ignition regime (< 1230 K). Similar τign behavior in the high-temperature regime was seen for both lubricants, and a regression analysis using τign data from both lubricants in this region produced the Arrhenius expression τign(μs) = 4.4 × 10−14exp(96.7(kcal/mol)/RT). While lubricant A was found to be less reactive in the intermediate-temperature regime, Mobil DTE 732 was less reactive in the low-temperature regime. As the low-temperature regime is more relevant to gas turbine conditions, Mobil DTE 732 is considered more desirable for system implementation. Chemical kinetic modeling was also performed using n-hexadecane models (a lubricant surrogate suggested in the literature). The current models are unable to reproduce the three regimes observed and predict activation energies much lower than those observed in the high-temperature regime, suggesting n-hexadecane is a poor surrogate for lubricant ignition. Additionally, experiments were conducted with Jet-A for temperatures between 1145 and 1419 K around 1 atm. Good agreement is seen with both literature data and model predictions, anchoring the experiment with previously established τign measurement methods and calculations. A linear regression analysis of the Jet-A data produced the Arrhenius expression: τign(μs) = 6.39 × 10−5exp(41.4(kcal/mol)/RT).

OBSERVATION OF PHASE SEPARATED La0.5Sr0.5MnO3 FILM

2006 ◽  
Vol 20 (05) ◽  
pp. 551-557 ◽  
Author(s):  
TONG LI ◽  
YONGSHENG DU ◽  
HUI YAN ◽  
DUNBO YUD
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Magnetron Sputtering ◽  
Low Temperatures ◽  
Energy Barrier ◽  
Hysteresis Loops ◽  
Rf Magnetron Sputtering ◽  
Thermal Motion ◽  
Powder Target

La 0.5 Sr 0.5 MnO 3 films on (001) LaAlO 3 were prepared by RF magnetron sputtering using powder target and were studied by SQUID and XPS. The XPS results show the formation of Mn 3+ and Mn 4+, indicating the coexistence of ferromagnetic (FM) and antiferromagnetic (AFM) clusters. SQUID measurement of LSMO on LAO and Si also support an interaction between them at low temperatures, resulting in the shift of hysteresis loops. Large coercivities at low temperature can be attributed to the pinning of both FM and AFM clusters and small coercivities at high temperature to the depinning of both FM and AFM phases, resulting from the thermal motion at higher temperatures which help to overcome the energy barrier and change the magnetic alignments.

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