scholarly journals Quantum chemical and master equation study of OH + CH2 O → H2 O + CHO reaction rates in supercritical CO2 environment

2018 ◽  
Vol 51 (1) ◽  
pp. 42-48 ◽  
Author(s):  
Elizabeth E. Wait ◽  
Artëm E. Masunov ◽  
Subith S. Vasu
Keyword(s):  
Master Equation ◽  
Quantum Chemical ◽  
Supercritical Co2 ◽  
Reaction Rates ◽  
Co2 Environment

scholarly journals Oxidation Behavior of Additively Manufactured 316L in a Supercritical CO2 Environment

2020 ◽  
Vol MA2020-02 (9) ◽  
pp. 1180-1180
Author(s):  
Rebecca Filardo Schaller ◽  
Michael Anthony Melia ◽  
Florent Bocher
Keyword(s):  
Supercritical Co2 ◽  
Oxidation Behavior ◽  
Co2 Environment

scholarly journals Effect of Supercritical CO2 on Steel Ductility at 450°-650°C

2021 ◽  
Author(s):  
Bruce A. Pint ◽  
Rishi Pillai ◽  
James R. Keiser
Keyword(s):  
Tensile Properties ◽  
Supercritical Co2 ◽  
Room Temperature ◽  
Reaction Rates ◽  
Significant Loss ◽  
Austenitic Steels ◽  
Maximum Temperature ◽  
Clear Correlation ◽  
Temperature Capability ◽  
Product Thickness

Abstract The compatibility of ferritic-martensitic (FM) and conventional and advanced austenitic steels with supercritical CO2 (sCO2) is being explored at 450°–650°C to determine their maximum temperature capability. In addition to measuring reaction kinetics and reaction product thickness, bulk carbon content and post-exposure room temperature tensile properties were assessed by exposing both alloy coupons and 25 mm long dogbone tensile specimens. After 1–2 kh exposures in 300 bar research grade (RG) sCO2, ∼9 and 12%Cr FM steels had similar behavior under these conditions. Consistent with the literature, higher Cr and Ni contents in alloy 316H provided lower reaction rates at 450° and 550°C, but limited benefit at 650°C with similar degradation of tensile properties and C ingress observed. An advanced austenitic Nb-modified 20Cr-25Ni alloy 709 provided the best compatibility even at 650°C with no C uptake detected after 1 kh and no significant loss in room temperature tensile properties after exposure. A clear correlation was observed under these conditions between the formation of a thin, protective Cr-rich oxide scale and the prevention of C ingress and tensile property degradation at 650°C.

Quantum Chemical and Master Equation Studies of the Methyl Vinyl Carbonyl Oxides Formed in Isoprene Ozonolysis

2005 ◽  
Vol 109 (47) ◽  
pp. 10710-10725 ◽  
Author(s):  
Keith T. Kuwata ◽  
Lukas C. Valin ◽  
Amber D. Converse
Keyword(s):  
Master Equation ◽  
Quantum Chemical ◽  
Methyl Vinyl ◽  
Carbonyl Oxides

Understanding the pitting corrosion mechanism of pipeline steel in an impure supercritical CO2 environment

2018 ◽  
Vol 138 ◽  
pp. 132-142 ◽  
Author(s):  
Yong Xiang ◽  
Chen Li ◽  
Wuermanbieke Hesitao ◽  
Zhengwei Long ◽  
Wei Yan
Keyword(s):  
Pitting Corrosion ◽  
Supercritical Co2 ◽  
Pipeline Steel ◽  
Corrosion Mechanism ◽  
Co2 Environment

scholarly journals Hybrid master equation for jump-diffusion approximation of biomolecular reaction networks

2019 ◽  
Vol 60 (2) ◽  
pp. 261-294
Author(s):  
Derya Altıntan ◽  
Heinz Koeppl
Keyword(s):  
Master Equation ◽  
Probability Density ◽  
Diffusion Approximation ◽  
Joint Probability ◽  
Planck Equation ◽  
Jump Diffusion ◽  
Reaction Rates ◽  
Conditional Probability Density ◽  
Multi Scale ◽  
Joint Probability Density

AbstractCellular reactions have a multi-scale nature in the sense that the abundance of molecular species and the magnitude of reaction rates can vary across orders of magnitude. This diversity naturally leads to hybrid models that combine continuous and discrete modeling regimes. In order to capture this multi-scale nature, we proposed jump-diffusion approximations in a previous study. The key idea was to partition reactions into fast and slow groups, and then to combine a Markov jump updating scheme for the slow group with a diffusion (Langevin) updating scheme for the fast group. In this study we show that the joint probability density function of the jump-diffusion approximation over the reaction counting process satisfies a hybrid master equation that combines terms from the chemical master equation and from the Fokker–Planck equation. Inspired by the method of conditional moments, we propose a efficient method to solve this master equation using the moments of reaction counters of the fast reactions given the reaction counters of the slow reactions. For each time point of interest, we then solve a set of maximum entropy problems in order to recover the conditional probability density from its moments. This finally allows us to reconstruct the complete joint probability density over all reaction counters and hence obtain an approximate solution of the hybrid master equation. Finally, we show the accuracy of the method applied to a simple multi-scale conversion process.

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