| 1. |
- Blurock, Edward
(författare)
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Characterizing complex reaction mechanisms using machine learning clustering techniques
- 2004
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Ingår i: International Journal of Chemical Kinetics. - : Wiley. - 0538-8066 .- 1097-4601. ; 36:2, s. 107-118
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Tidskriftsartikel (refereegranskat)abstract
- A machine learning conceptual clustering method applied to reaction mechanisms provides an automatic and, hence, unbiased means to differentiate between reactive phases within a total reactive process. Similar reactive phases were defined by means of local reaction sensitivity values. The method was applied to the Hochgreb and Dryer aldehyde combustion mechanism of 36 reactions. Three major time ranges were found and characterized: an initial phase of aldehyde reaction, an intermediate phase where only a small amount of aldehyde is left, and an end phase of reactions to final products. Further refinements of these phases into subtime intervals were found. All ranges found could be chemically justified. This method is meant as a supplement to existing methods of mechanism analysis and its main purpose is the automatic characterization of existing mechanisms and can potentially be used for mechanism reduction.
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| 2. |
- Blurock, Edward
(författare)
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Detailed mechanism generation. 1. Generalized reactive properties as reaction class substructures
- 2004
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Ingår i: Journal of Chemical Information and Computer Sciences. - : American Chemical Society (ACS). - 0095-2338 .- 1520-5142. ; 44:4, s. 1336-1347
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Tidskriftsartikel (refereegranskat)abstract
- This paper, the first in a series on the automatic generation of detailed hydrocarbon mechanisms for hydrocarbons, describes how generalized reaction types, specifically the 25 types outlined by Curran et al. for heptane and isooctane combustion, can be translated into general reaction classes. Each type description from Curran et al. ranges from specific, such as differentiating among 1degrees, 2degrees, and 3degrees centers, to nonspecific such as specifying intermediate specific as "products". In the latter case, additional interpretation of the reaction type must be extrapolated from other sources. The types are translated to the substructure "patterns" representing reaction classes. The success of fully translating all the rate and structural information described in these reaction types as they are defined in the literature demonstrates the power of the approach used here. A comparison of the generated reactions using these 25 types with that of a hand-produced heptane mechanism showed that, aside from well-defined exceptions, the set of reactions were almost identical. Often just the elimination of selected species (and sometimes reactions) was enough to make them identical. A notable exception was the use of lumped species in the hand-produced mechanism. The purpose of this paper is to show that an established set of reaction type descriptions can be translated to reaction classes suitable for automatic mechanism generation. A further goal of this paper is to show that these classes can be used to generate a detailed mechanism that mimics a hand produced one.
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| 3. |
- Blurock, Edward
(författare)
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Detailed mechanism generation. 2. Aldehydes, ketones, and olefins
- 2004
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Ingår i: Journal of Chemical Information and Computer Sciences. - : American Chemical Society (ACS). - 0095-2338 .- 1520-5142. ; 44:4, s. 1348-1357
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Tidskriftsartikel (refereegranskat)abstract
- Generalized reaction classes for the consumption and decomposition of aldehydes, ketones, and olefins are described. These classes are important for generating not only reactions for the consumption of the branching agents of low-temperature hydrocarbon combustion but also reactions of the oxidation of alkenes and the decomposition of cyclic ethers. These reaction classes have been extrapolated from specific reactions of existing validated mechanisms. The reaction patterns making up the class were derived by identifying the reactive center of the specific reactions and the important surrounding functional groups. The rates used currently are definitely "first guesses" based on these specific reactions. The reaction classes in this paper supplement the reaction classes derived from accepted reaction types in the previous paper in this series. The purpose of this paper is to outline a complete (with very few exceptions) set of reaction classes which describe the C-5 and C-6 products of the low-temperature and cyclic ether path in the heptane and isooctane mechanisms.
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| 4. |
- Lövås, Terese, et al.
(författare)
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Towards dynamically reduced mechanisms based on domain splitting
- 2003
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Ingår i: Computational Fluid and Solid Mechanics 2003, vols 1 and 2, Proceedings. - 9780080440460 ; , s. 1430-1433
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Konferensbidrag (refereegranskat)abstract
- We present a method for developing dynamically reduced chemical mechanisms based on the quasi steady state assumption and a domain splitting procedure. This procedure carries out the reduction within each domain separately according to a steady state selection parameter valid for the corresponding domain. The domains are defined according to a clustering algorithm. The method is applied to calculations of ethene diffusion flamelets.
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