Flame Propagation with a Sequential Reaction Mechanism

1982 ◽  
Vol 42 (6) ◽  
pp. 1175-1188 ◽  
Author(s):  
Stephen B. Margolis ◽  
Bernard J. Matkowsky
Keyword(s):  
Reaction Mechanism ◽  
Flame Propagation ◽  
Sequential Reaction

scholarly journals The kinetic properties and reaction mechanism of histamine methyltransferase from human skin

1980 ◽  
Vol 187 (3) ◽  
pp. 819-828 ◽  
Author(s):  
D M Francis ◽  
M F Thompson ◽  
M W Greaves
Keyword(s):  
Reaction Mechanism ◽  
Human Skin ◽  
Substrate Inhibition ◽  
Kinetic Properties ◽  
Sequential Reaction ◽  
Methyl Group ◽  
Michaelis Constants ◽  
Histamine Methyltransferase ◽  
The Mean ◽  
Inhibited Enzyme

The substrate kinetic properties of histamine methyltransferase from human skin were studied at limiting concentrations of both histamine and S-adenosylmethionine. Substrate inhibition by histamine was observed at concentrations above 10 microM. Primary plots showed evidence of a sequential reaction mechanism. The Michaelis constants were derived from secondary plots of slopes from the primary plots ([S]/v versus [S]) versus reciprocal of the second substrate concentration. The mean Km values for histamine and S-adenosylmethionine were 4.2 and 1.8 microM respectively. Histamine in concentrations of 25-100 microM inhibited enzyme activity uncompetitively with respect to S-adenosylmethionine. No substrate inhibition was observed with S-adenosylmethionine. To elucidate the reaction mechanism further, inhibition by the two products, S-adenosylhomocysteine and 1-methylhistamine, was studied. S-Adenosylhomocysteine inhibited non-competitively with respect to histamine and competitively with respect to S-adenosylmethionine. 1-Methylhistamine inhibited non-competitively with respect to histamine and to S-adenosylmethionine. These results are interpreted as providing evidence for an ordered sequential Bi Bi reaction mechanism, with the methyl-group donor S-adenosylmethionine as the first substrate that adds to the enzyme and histamine as the second substrate. 1-Methylhistamine is the first product to leave the enzyme and S-adenosylhomocysteine is the second. The results are discussed in terms of the possible role that this enzyme could play in the modulation of histamine-mediated reactions in skin.

The Effects of Perfluoroalkyl Carboxylic Acid Coating of Al Particles to Flame Propagation

2009 ◽  
Author(s):  
B. Dikici ◽  
M. L. Pantoya ◽  
R. J. Jouet
Keyword(s):  
Reaction Mechanism ◽  
Carboxylic Acid ◽  
Metal Oxide ◽  
Flame Propagation ◽  
Thermal Equilibrium ◽  
Acid Treatment ◽  
Heat Of Combustion ◽  
Oxide Composites ◽  
Acid Coating

In this study, two types of nano-Al/metal oxide composites are examined. The first Al sample is passivated with Al2O3 and treated with perfluoroalkyl carboxylic acid (C13F27COOH). The second Al sample is devoid of an alumina shell and instead passivated with perfluoroalkyl carboxylic acid (C13F27COOH). The goal of this study is to understand the role of the passivation shell and associated reaction mechanism on flame propagation. Results show that when there is no alumina passivation shell encasing the Al core the flame propagation rates are reduced by two orders of magnitude. All flame propagation experiments were performed in a confined flame tube apparatus which may not be ideal for characterizing materials with significantly different ignition sensitivities. Results indicate that flame speeds measured with this apparatus are dependent on the ignition sensitivity of the mixture. Acid treated Al particles are shown to be roughly five times less ignition sensitive than the Al particles with no acid treatment; however, both particles produce roughly the same heat of combustion in thermal equilibrium measurements.

scholarly journals Numerical Investigation of Combustion Characteristics of a Wave Rotor Combustor Based on a Reduced Reaction Mechanism of Ethylene

2018 ◽  
Vol 2018 ◽  
pp. 1-21 ◽  
Author(s):  
Jianzhong Li ◽  
Li Yuan ◽  
Wei Li ◽  
Kaichen Zhang
Keyword(s):  
Reaction Mechanism ◽  
Flame Propagation ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Pressure Rise ◽  
Combustion Characteristics ◽  
Wave Rotor ◽  
Elementary Reactions ◽  
Coupling Time

To improve simulations of the flame and pressure wave propagation process and investigate the combustion characteristics of a wave rotor combustor (WRC), direct relation graphs with error propagation (DRGEP), quasi-steady-state assumption (QSSA), and sensitivity analysis were used to establish a reduced reaction mechanism comprised of 23 species and 55 elementary reactions, based on the LLNL N-Butane mechanism. The reduced reaction mechanism of ethylene was combined with an eddy dissipation concept (EDC) model to simulate the flame propagation characteristics in a simplified WRC channel. The effects of spoilers with different blockage ratios and hot-jets of different species on combustion characteristics of flame propagation and pressure rise in the WRC channel were investigated. When the heated inert air was used as hot-jet, the ignition delay time of WRC would increase, which indicated that the activity of the burned gas from the hot-jet igniter would affect the ignition delay time. The spoiler facilitates the coupling of flame and shock waves to reduce the coupling time and distance. With the blockage ratio of the spoiler increasing, the coupling time and distance would be reduced.

scholarly journals Influence of Aluminum Passivation on the Reaction Mechanism: Flame Propagation Studies

2009 ◽  
Vol 23 (9) ◽  
pp. 4231-4235 ◽  
Author(s):  
Birce Dikici ◽  
Steven W. Dean ◽  
Michelle L. Pantoya ◽  
Valery I. Levitas ◽  
R. Jason Jouet
Keyword(s):  
Reaction Mechanism ◽  
Flame Propagation ◽  
Aluminum Passivation

Reduction kinetics of purified rat liver cytochrome P-450. Evidence for a sequential reaction mechanism dependent on the hemoprotein spin state

Biochemistry ◽  
1984 ◽  
Vol 23 (20) ◽  
pp. 4526-4533 ◽  
Author(s):  
Paul P. Tamburini ◽  
G. Gordon Gibson ◽  
Wayne L. Backes ◽  
Stephen G. Sligar ◽  
John B. Schenkman
Keyword(s):  
Reaction Mechanism ◽  
Rat Liver ◽  
Spin State ◽  
Reduction Kinetics ◽  
Sequential Reaction ◽  
Liver Cytochrome ◽  
Kinetics Of ◽  
Cytochrome P 450
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