scholarly journals Activation energies as the validity criterion of a model for complex reactions that can be in oscillatory states

2007 ◽  
Vol 39 (1) ◽  
pp. 77-83 ◽  
Author(s):  
S. Anic ◽  
M. Kostic ◽  
M. Ninic ◽  
S. Blagojevic ◽  
Lj. Kolar-Anic
Keyword(s):  
Reaction System ◽  
Activation Energies ◽  
Oscillatory Process ◽  
Oscillatory Reaction ◽  
Crucial Importance ◽  
Oscillatory Dynamic ◽  
Validity Criterion ◽  
Apparent Activation Energies ◽  
Period Duration ◽  
Oscillatory Period

Modeling of any complex reaction system is a difficult task. If the system under examination can be in various oscillatory dynamic states, the apparent activation energies corresponding to different pathways may be of crucial importance for this purpose. In that case the activation energies can be determined by means of the main characteristics of an oscillatory process such as pre-oscillatory period, duration of the oscillatory period, the period from the beginning of the process to the end of the last oscillation, number of oscillations and others. All is illustrated on the Bray-Liebhafsky oscillatory reaction.

scholarly journals Effect of CaO on catalytic combustion of semi-coke

2021 ◽  
Vol 10 (1) ◽  
pp. 011-020
Author(s):  
Luyao Kou ◽  
Junjing Tang ◽  
Tu Hu ◽  
Baocheng Zhou ◽  
Li Yang
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
Combustion Rate ◽  
Activation Energies ◽  
Combustion Reaction ◽  
Tg Analysis ◽  
Conversion Rates ◽  
Apparent Activation Energies ◽  
Ozawa Integral Method ◽  
Addition Amount

Abstract Generally, adding a certain amount of an additive to pulverized coal can promote its combustion performance. In this paper, the effect of CaO on the combustion characteristics and kinetic behavior of semi-coke was studied by thermogravimetric (TG) analysis. The results show that adding proper amount of CaO can reduce the ignition temperature of semi-coke and increase the combustion rate of semi-coke; with the increase in CaO content, the combustion rate of semi-coke increases first and then decreases, and the results of TG analysis showed that optimal addition amount of CaO is 2 wt%. The apparent activation energy of CaO with different addition amounts of CaO was calculated by Coats–Redfern integration method. The apparent activation energy of semi-coke in the combustion reaction increases first and then decreases with the increase in CaO addition. The apparent activation energies of different samples at different conversion rates were calculated by Flynn–Wall–Ozawa integral method. It was found that the apparent activation energies of semi-coke during combustion reaction decreased with the increase in conversion.

APPLICABILITY OF BRAY-LIEBHAFSKY REACTION FOR CHEMICAL COMPUTING

2021 ◽  
Author(s):  
Željko Čupić ◽  
◽  
Ana I vanović Šašić ◽  
Stevan Maćešić ◽  
Slobodan Anić ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Numerical Simulations ◽  
Reaction System ◽  
Dynamic State ◽  
Oscillatory Reaction ◽  
Oscillatory Reactions ◽  
Dynamic States

The first discovered homogeneous oscillatory reaction was the Bray-Liebhafsky (BL) one, described in a paper published exactly 100 years ago. However, the applicability of oscillatory reactions in chemical computing was recently discovered. Here we intend to expose the native computing concept applied to intermittent states of the BL reaction, because we believe that this particular state may have some advantages. For this purpose, numerical simulations will be used based on the known model. Sequences of perturbations will be introduced by adding iodate (IO3-) and hydrogen peroxide (H2O2), separately, as well as in various combinations with one another. It will be shown that dynamic states obtained after perturbations with same species depend very much on the sequence in which these species were used in perturbations. Additionally, it will be shown that obtained dynamic states shift the system from chaotic intermittent dynamic state to different complex periodic states. Hence, the applicability of the BL reaction system in chemical computing was demonstrated.

Phosphate release from dog erythrocytes

1962 ◽  
Vol 202 (5) ◽  
pp. 981-983 ◽  
Author(s):  
John M. Ginski ◽  
John F. Thomson ◽  
Akira Omachi
Keyword(s):  
Inorganic Phosphate ◽  
Activation Energies ◽  
Glycolytic Enzymes ◽  
Similar Magnitude ◽  
Anaerobic Conditions ◽  
Phosphate Release ◽  
Precursor Pool ◽  
Apparent Activation Energies ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

P32 release from dog erythrocytes previously incubated with radioactive inorganic phosphate was investigated. Under both aerobic and anaerobic conditions, apparent activation energies of similar magnitude, 25,000 cals/mole, were obtained. However, P32 release was lower in the absence of oxygen and greater in the presence of iodoacetate. These results suggest that the cellular pool from which P32 is released is accessible to glycolytic enzymes and that the rate of P32 release is related in some manner to the orthophosphate concentration in the precursor pool.

Nitric oxide and oxygen reactions with 1-butene over manganese(III) oxide

1983 ◽  
Vol 61 (12) ◽  
pp. 2767-2772 ◽  
Author(s):  
Robert Anderson Ross ◽  
Craig Fairbridge
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Reaction Rates ◽  
Activation Energies ◽  
Complete Combustion ◽  
Differential Flow ◽  
Exponential Factors ◽  
Unburned Hydrocarbons ◽  
Apparent Activation Energies ◽  
Nitrate Species

Reactions of 1-butene with nitric oxide from 623 to 723 K and with oxygen from 433 to 573 K have been studied in a differential flow system over manganese(III) oxide. Nitrous oxide was formed in the reaction of the hydrocarbon with nitric oxide along with products of complete combustion. The apparent activation energies were respectively 69 ± 4, 78 ± 4, and 30 ± 4 kJ mol−1 for nitrogen, carbon dioxide, and nitrous oxide reaction rates. The corresponding pre-exponential factors were 1.72 × 10−1 and 1.16 mol0.5 L−0.5 m2 g−1, and 1.99 × 10−2 mol−0.35 L0.35 m2 g−1. In the reaction with oxygen, apparent activation energies of 183 ± 4, 523 to 503 K, and 88 ± 4 kJ mol−1, 503 to 433 K, were determined with pre-exponential factors 1.74 × 1015 and 2.94 × 105 mol0.3 m−2 g−1. During catalysis the oxide underwent a partial phase change from α to γ in both reactions. Additionally, nitrate species were present on the surface after oxidation with nitric oxide. Kinetic expressions have been derived and mechanisms proposed for both reactions which may occur in emission control systems requiring the removal of NOx and unburned hydrocarbons.

Interpretation of Apparent Activation Energies for Electron Transport in Dye-sensitized Nanocrystalline Solar Cells

2006 ◽  
Vol 110 (28) ◽  
pp. 13694-13699 ◽  
Author(s):  
Laurence M. Peter ◽  
Alison B. Walker ◽  
Gerrit Boschloo ◽  
Anders Hagfeldt
Keyword(s):  
Solar Cells ◽  
Electron Transport ◽  
Activation Energies ◽  
Dye Sensitized ◽  
Apparent Activation Energies
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