Single-stage optimization problem with soft restrictions

Most chemical processes are designed with the application of inaccurate mathematical models. Therefore, the objective of optimized chemical processes under uncertainty becomes an actual problem of chemical technology. It is necessary to design a process satisfying all the requirements of the designer regardless of the changing external and internal factors. This paper considers a problem of single-stage optimization with soft restrictions. Moreover, these soft restrictions should be provided with some known probability. It is necessary to note that solution of this problem of single-stage optimization needs the calculation of multidimensional integrals for mathematical expectancy of the criterion functions and probabilistic restrictions. This paper considers an approach to solution of this problem of single-stage optimization based on transforming the probabilistic restrictions into deterministic ones. The efficiency of this approach was illustrated by a computational experiment.     

Optimal design of a distillation column system of a given topology

The problem of the optimal design of a rectifying column system of a given topology is presented as a problem of discrete-continuous nonlinear programming. The branch-and-bound method is suggested for solving the problem. To find the values of the lower bound of the optimality criterion, minimum cost, we suggest an approach that proceeds from discrete variables (the number of trays in the reinforcing and exhaustive parts of the columns) to continuous variables. The efficiency of this approach is demonstrated on the example of the design of a rectifying system composed of three rectifying columns for separating a four-component mixture.     

Classification and database of thermophysical characteristics of heat protective materials

Classification and identification marking of heat protective materials and a database of their thermophysical characteristics are developed. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 73, No. 1, pp. 39–43, January–February, 2000.     

Effect of a diet with an increased protein content on reparative processes in experimental ulcerous lesions of the gastric and duodenal mucosa

Experimental rats were subjected to an extreme action: 3-hour immobilization with simultaneous electrostimulation. A complete healing of erosion-ulcerous defects of the gastroduodenal mucosa was recorded in rats given diets with an increased (by 4 g) protein content (group I), on day 5. The mucosal affections in the rats receiving a standard ration still persisted. The content of creatine-phosphate in the gastric wall tissue, decreased under the extreme action, was rapidly recovered in group I rats, no changes in the proper fluorescence level of reduced NADH and flavoproteins were noted. In group II rats both parameters returned to normal only on day 5. Blood serum ceruloplasmin (CP) activity increased during first 3 days with a similar rate in both animal groups. However, in the following 2 days CP activity in group I rats became completely normal, while that in group II animals was still rising. The results of the study have shown that the diet with increased protein content stimulates epithelization of the gastroduodenal mucosa due to the improvement of the bioenergy processes in the gastroduodenal area, and to intensified adaptation potentialities of the body.     

Wear resistance of gasobaric nitrided layers on steel 12Kh18N10T

The structure, hardness, phase composition, and wear intensity of the nitrided layer on steel 12Kh18N10T formed in a medium of nitrogen at a pressure of 160 MPa at a temperature of 1150°C with a hold of 3 h are studied.