Gravitational Search and Harmony Search Algorithms for Solving the Chemical Kinetics Optimization Problems

The article is dedicated to the analysis of the global optimization algorithms application to the solution of inverse problems of chemical kinetics. Two heuristic algorithms are considered - the gravitational search algorithm and the harmony algorithm. The article describes the algorithms, as well as the application of these algorithms to the optimization of test functions. After that, these algorithms are used to search for the kinetic parameters of two chemical processes – propane pre-reforming on Ni-catalyst and catalytic isomerization of pentane-hexane fraction. For the first process both algorithms showed approximately the same solution, while for the second problem the gravitational search algorithm showed a smaller value of the minimizing function. Wherefore, it is concluded that on large-scale problems it is better to use the gravitational search algorithm rather than the harmony algorithm, while obtaining a smaller value of the minimizing function in a minimum time. On low-scale problems both algorithms showed approximately the same result, while demonstrating the coincidence of the calculated data with the experimental ones

Modern information technologies in construction of kinetic models for reactions of metal complex catalysis

AbstractFor detailed study of complex chemical reactions mechanisms experiment is conducted for selected private reactions. This causes a problem of kinetic parameters getting—the same set of rate constants must describe both public and private reaction stages, and also a general mechanism. In this paper, solution of this problem for a reaction of olefins hydroalumination is proposed. To optimize the computational process a methodology of parallelization is elaborated. On the base of parallel computations, a kinetic model for the reaction assigned is constructed, and on its base, the physical and chemical conclusions about reaction mechanism are done

A Logic with Reverse Modalities for History-preserving Bisimulations

We introduce event identifier logic (EIL) which extends Hennessy-Milner logic by the addition of (1) reverse as well as forward modalities, and (2) identifiers to keep track of events. We show that this logic corresponds to hereditary history-preserving (HH) bisimulation equivalence within a particular true-concurrency model, namely stable configuration structures. We furthermore show how natural sublogics of EIL correspond to coarser equivalences. In particular we provide logical characterisations of weak history-preserving (WH) and history-preserving (H) bisimulation. Logics corresponding to HH and H bisimulation have been given previously, but not to WH bisimulation (when autoconcurrency is allowed), as far as we are aware. We also present characteristic formulas which characterise individual structures with respect to history-preserving equivalences.Comment: In Proceedings EXPRESS 2011, arXiv:1108.407

Implementation of the Multicomponent Algorithm of the Interdisciplinary Teaching Modules into Liberal Education of the University Students

The importance of the problem presented in the article is determined by the complex of educational strategies, goals and objectives of liberal education of the student - a tomorrow's professional in modern production who shows a new level of cultural identity the main characteristics of which are: awareness of the importance of liberal education in achieving life-plan, self-identification in society and at work; aspiration to make a conscious and decent choice of human values; formedness of consciousness and behavior, readiness to intercultural communication as a combination of competencies of productive interaction with people in the multicultural world. The purpose of the article is to scientifically and methodically underpin the efficiency of the multicomponent algorithm of the interdisciplinary teaching modules in liberal education of the university students. The paper submits the innovative approaches of self-transformation and self-identification of the university students in liberal education in the process of employing a multicomponent algorithm (the target, didactic, organizational - methodological, content-related and procedural components) of the interdisciplinary teaching modules. The article submissions are applicable for the teachers of the Humanities, academic registrars at the social sciences departments of the universities, graduate students and young scientists and students engaged in scientific activities. DOI: 10.5901/mjss.2015.v6n2s3p19

PIK3CA mutations are common in lobular carcinoma in situ, but are not a biomarker of progression

Sample and data collection were funded by Cancer Research UK. Analysis was funded by Breast Cancer Now, the Rosetrees Trust, Guys & St Thomas’ Charity (CanHelp) and the National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy’s and St. Thomas’ NHS Foundation Trust and King’s College London

Diffusion Mechanism of Li Argyrodite Solid Electrolytes for Li-Ion Batteries and Prediction of Optimized Halogen Doping: The Effect of Li Vacancies, Halogens, and Halogen Disorder

Using density functional theory molecular dynamics simulations, the origin of the Li-ion conductivity in argyrodite solid electrolytes is investigated. The simulations show that besides Li-ion vacancies in Li6PS5Cl and Li6PS5Br, the influence of halogen atoms on their local surroundings also plays an important role in Li-ion diffusion. The difference in Li-ion conductivity between Li6PS5Cl and Li6PS5I, which is several orders of magnitude, is caused by the distribution of the halogen ions over the available crystallographic sites. This suggests that altering the halogen distribution in Li argyrodites during synthesis could increase the Li-ion conductivity of these materials. For Li6PS5Cl, the simulations predict an optimal Cl distribution of 1:3 over sites 4a and 4c, resulting in a Li-ion conductivity that is 2 times larger than that of the currently prepared materials. On the basis of these results, simulations were performed on Li5PS4X2 (X = Cl, Br, or I), which show Li-ion conductivities similar to those of Li6PS5Cl and Li6PS5Br, suggesting that the Li5PS4X2 compounds are interesting new compositions for solid state electrolytes.Accepted Author ManuscriptRST/Fundamental Aspects of Materials and Energ

Computer Simulation of Coke Sediments Burning from the Whole Cylindrical Catalyst Grain

The article is devoted to the development of the mathematical model of oxidative regeneration of the cylindrical catalyst grain. The model is constructed using a diffusion approach to modeling catalytic processes. The model is based on the equations of material and thermal balance. Mass transfer in the catalyst grain is carried out due to diffusion and the Stefan flow resulting from a decrease in the reaction volume during sorption processes. Chemical transformations of substances are taken into account as a source term in the equation. The thermal balance of the catalyst grain is described by a thermal conductivity equation, with an inhomogeneous term responsible for heating the grain during exothermic chemical reactions. The effective coefficients of heat capacity and thermal conductivity of the catalyst grain, which are determined taking into account the porosity of the grain depending on temperature, were used to calculate the thermal balance of the catalyst grain. The dependencies are approximated using the method of least squares based on experimental data. Different boundary conditions for the developed model allow calculating the main characteristics of the oxidative regeneration process for a whole catalyst grain under different conditions. The mathematical model of oxidative regeneration of a cylindrical catalyst grain is described by a stiff system of differential equations. Splitting by physical processes is applied to avoid computational difficulties. The calculation of flows is carried out sequentially: first, chemical problems are solved using the Radau method, then the diffusion and thermal conductivity equations are solved by the finite volume method. The result of the algorithm implemented in C++ is a picture of the distribution of substances and temperature along the cylindrical grain of the catalyst

Computer Simulation of Coke Sediments Burning from the Whole Cylindrical Catalyst Grain

The article is devoted to the development of the mathematical model of oxidative regeneration of the cylindrical catalyst grain. The model is constructed using a diffusion approach to modeling catalytic processes. The model is based on the equations of material and thermal balance. Mass transfer in the catalyst grain is carried out due to diffusion and the Stefan flow resulting from a decrease in the reaction volume during sorption processes. Chemical transformations of substances are taken into account as a source term in the equation. The thermal balance of the catalyst grain is described by a thermal conductivity equation, with an inhomogeneous term responsible for heating the grain during exothermic chemical reactions. The effective coefficients of heat capacity and thermal conductivity of the catalyst grain, which are determined taking into account the porosity of the grain depending on temperature, were used to calculate the thermal balance of the catalyst grain. The dependencies are approximated using the method of least squares based on experimental data. Different boundary conditions for the developed model allow calculating the main characteristics of the oxidative regeneration process for a whole catalyst grain under different conditions. The mathematical model of oxidative regeneration of a cylindrical catalyst grain is described by a stiff system of differential equations. Splitting by physical processes is applied to avoid computational difficulties. The calculation of flows is carried out sequentially: first, chemical problems are solved using the Radau method, then the diffusion and thermal conductivity equations are solved by the finite volume method. The result of the algorithm implemented in C++ is a picture of the distribution of substances and temperature along the cylindrical grain of the catalyst