Advanced Materials Research Vol. 1040

Abstract: This article describes the simulation and modeling software for the process of polymerization of vinyl chloride suspension process for automatic control and maintaining of optimum modes of chemical transformations. Simulation and modeling software operating in the training mode allows acquiring the skills of process control and in supervisory mode to evaluate the level of training of operating personnel.

Abstract: This paper summarize idealized theoretical studies of bicomponent particle packing parameters, affecting the phase and pore structure of obtained materials. Such a kind of analysis can be used both in theoretical consideration of material engineering problems and in chemical industry. The effects of key variables on the relationship between packing fraction and particle size were re-examined for general application. Potential applications of these results include synthesis of nanopaterials, adsorbents, catalyst carriers and packing for chromatographic columns. Directions for future research are suggested.

Abstract: In material science the simultaneous application of theoretical examination, experimental and numerical studies are often required. This is especially true for modern composite materials with extra inter-boundary nanoscale layers. Thickness of layers is usually about tens of nanometers, while diameters of particles of filler are about several hundreds of nanometers. Thus, during the theoretical study and numerical experiments the size and properties of inter-boundary layer must be taken into account. The proper choice of the model is the key factor for the adequate results of simulation. In the present work we have derived such a model. The system under investigation – disperse-filled composite material with inter-boundary layers of different properties – is represented by particle system; these classes of models can be characterized by high generality. Initial equation for the law of motion is sequentially extended with terms which account for different phenomena – conservative binary interaction, non-conservative interaction with environment, interaction with planar boundaries and non-conservative particle-particle interaction via inter-boundary layer. The reduction of the law of motion to the system of ordinary differential equations had opened the possibility for utilization of the vast majority of numerical algorithms for the prediction of the structural properties of nanomodified sulfur-based composite.

Abstract: The simple isothermal problem is formulated to describe the composition of surface layer change during particle beam action. The finiteness of relaxation time for mass flux is taken into account. The analytical solutions for some limiting cases are presented. Numerical solution of total problem is carried out. It is shown that concentration distributions for reactants and for reaction product depend on relation between various physical scales.

Abstract: The problem has been analyzed on alloying elements redistribution between the coating (containing Cr and N) and the substrate (Si) in condition of surface heating. The model takes into account the effect of thermal diffusion on the redistribution of elements. The analytical solution of the particular linearized problem about redistribution of elements in the substrate coating is presented. It is shown that the thermal diffusion significantly affects the impurity distribution, resulting in the appearance of supersaturated or depleted regions.

Abstract: Dynamics of radiative, near-limit, stretched premixed flames is investigated analytically and numerically. Investigation of counterflow premixed flames stability is important for the development of new combustion technologies such as those associated with low-NOx emission, lean burn and material synthesis. Emphasis is paid on the linear stability of multiple flame regimes. The present analysis, for the first time, gives out a dispersion equation describing growth rate of small spatial perturbations of the flame front. The stability diagram is obtained and the region of instability is distinguished.

Abstract: Diffusion research is important for understanding of many processes based on mass transfer. In many respects, diffusion, determines physical and mechanical characteristics for new materials with fine-dispersed matter and a large number of grain boundaries and phases. Models of diffusion along grain boundaries and their modifications are widely known in literature, but they are not always applicable to nanomaterials due to indistinct determination of some notions. At the present paper the model of diffusion is presented, which considers boundaries and area near boundaries as a phase with special properties. Mass transfer between the volume of a grain and a boundary phase is taken into account. The approximate analytical solution of the problem is formulated. In the general case the problem is solved numerically. Non monotonic distributions of concentrations in volume are obtained.

Abstract: A two-dimensional two-temperature model of shale stratum heating by high-frequency electromagnetic field is proposed. The heat exchange between solid rock and gas contained in pores is shown to significantly affect temperature field characteristics. The stratum gas filtration and reaction heat effects are taken into account as a first approximation.

Abstract: This article considers the description of elastoviscoplastic deformation for FCC crystallite. The deformation model for crystallite is necessary for building the model of a polycrystal. The elastoviscoplastic model is used to consider the crystalline structure using crystalline directions and also using the continuum mechanics approach – averaging by the representative macrovolume. FCC crystalline plastic deformations are considered as a slip of dislocations on slipping systems. А pure fcc cuprum is used аs a material. The algorithm for description of the proposed measures of the stress-strain state is considered, and hardening laws are analyzed. The problem of stochastic optimization of inelastic crystalline deformation is solved. Hardening modules and initial critical stresses are identified and accepted stochastically. The squared difference between the computational and experimental stress intensity for several points have been used as the target function. To solve the optimizing problem, the authors have used the min-max model considering the solution with the least favorable conditions for controlling vector. Nelder-Mead method (numerical method for direct search) is applied to solve the optimization problem. We have provided a description and analysis of the numerical results, recommendations for choosing the values of the identified parameters.

Abstract: The numerical modeling problem is solved using a direct formulation of the boundary element method. The integral Laplace transform is used, as well as time-step methods of its numerical inversion. Matrices of fundamental and singular solutions are computed with the help of a combined direct-interpolation approach. The computational results obtained are compared with the results of other authors.