Predicting Emissions from the Chemical and Energy Industries: Progress in Applying Modeling Approaches

Theoretical Foundations of Chemical Engineering - A review of international experience in the development and implementation of emissions monitoring systems based on mathematical models at...     

Current Theoretical and Applied Research on Energy- and Resource-Saving Highly Reliable Chemical Process Systems Engineering

Theoretical Foundations of Chemical Engineering - The history of the formation and development of a new field of research in chemical technology, such as the theory of chemical process systems...     

Calculation of thermodynamic properties of SF<Subscript>6</Subscript> including the critical region. Thermal functions and speed of sound

Specific heats C _v and C _p, entropy S, enthalpy H, and speed of sound W have been calculated using a new thermal equation of state with a small number of variable constants, which includes regular and scale contributions with a new transition function. The calculation results correspond to the accuracy level of the modern reference equations of state with a large number of determined parameters in the regular behavioral region of SF₆ properties; in the critical region, these results make it possible to supplement the existing reference data with the related tables, taking into account the scaling-theory advances. The experimental and tabular data on C _v, C _p, S, H, and W have not been used to determine the constants of the calculation equations (except for isochoric specific heat, C _v, in the ideal-gas state). These data have been applied only for comparison of the calculated values with the experimental and tabular values. To calculate the behavior of thermal properties in the critical region, universal critical indices α, β, and γ have been used according to the threedimensional Ising model. The mean error in describing thermal properties of SF₆ does not exceed the error of the existing experimental data. The calculated values coincide with the modern reference data in the regular region in the entire range of gas and liquid states. The discrepancies in the critical region are due to the application of the scale equation of state (in contrast to the regular equations used previously in this region for composing reference tables).     

Study of the thermal characteristics of phosphate raw materials in the annealing temperature range

In this paper, the thermal characteristics of phosphate raw materials have been studied, including thermal conductivity and volumetric heat capacity in the temperature range that has practical significance in the chemical and technological system of thermal preparation of raw materials. The method of the regular regime of the third kind and the method for solving the inverse heat-conduction problem have been used based on the joint solution of the equations of heat transfer and the kinetics of chemical reactions taking into account the most important accompanying phenomena. A dilatometric analysis of the studied samples of phosphate raw material has been presented.     

Monte Carlo modelling of wet-chemical lithography with masks

We propose Monte Carlo simulation of the etching process in two dimensions for the manufacture of microchannels and microcavities on a solid substrate. The method combines the effect of two different regimes based on diffusion-limited disaggregation and reaction-limited erosion, respectively. Besides, the role of the selectivity in site extraction is taken into account to foresee the effects of the temperature of the eroding bath. This technique proves to be a valid alternative to more complex analytical methods to describe surface decay processes in the presence of overhangs. The relevant geometries of the etched surfaces are analyzed, and other statistical properties of the cavities are discussed and compared to the ones predicted by continuum models.     

Project management in the nanotechnology industry: Specifics and possibilities of taking them into account

The characteristics of projects in the nanotechnology industry are considered from the viewpoint of resource provision and conditions of realization, and the specifics of project management problems in the nanotechnology industry are shown. The advantages and disadvantages of the most widespread project management methods are shown, and the possibilities of their application to project management problems in the subject area are evaluated. A project simulation approach based on the use of temporal logic tools is proposed. The advisability of developing branching point-interval time methods for the simulation of nanotechnology projects is substantiated.     

Computer molecular-dynamics simulation of the structure of crystal nanomaterials

The molecular-dynamics simulation of crystal system of silicon carbide at various temperatures has been performed using methods and programs of computer molecular design. Graphs of radial-distribution functions have been obtained for Si-C pairs of atoms, as well as the configurations of atoms in crystal systems at various temperatures. The dependence of the melting point of the SiC crystal system vs. the characteristics of the initial crystal structure to the approximation of the given Tersoff potential and molecular assembly has been studied at the constant number of particles, pressure, and temperature.     

Semi-Markovian models of the functioning of complex chemical engineering systems

This article deals with the general approaches to the construction of semi-Markovian models of chemical engineering systems. The basic lines of development of the semi-Markovian modeling apparatus, used for the determination of the rational set of measures to ensure the models’ economically efficient functioning, are shown. Expressions for the characterization of the maintenance service system and the repair of complex chemical engineering facilities are suggested.     

Wavelet-neuro-heuristics complex procedure of diagnostics of point defects of sheet glass

An analysis of the principal types of the defects of sheet glass that appear upon its production is given. The wavelet-neuron-heuristics procedure of diagnostics of point defects of sheet glass has been suggested and algorithm of its realization has been developed. The example of the diagnostics of a “closed bubble” defect has been given. The developed algorithmic software is designed for use in the automated control system of multistep production of high-quality sheet glass.