Global identification of complex static systems with hierarchical structure: Deterministic problem

The paper deals with a deterministic case of the identification problem of static complex systems with hierarchical structure, in which the globally optimal model of the whole system as a hierarchical configuration of models of individual subsystems is obtained

The considerations are confined to hierarchical complex systems, in which

(a) subsystems belonging to the same levels arc not interconnected

(b) the individual subsystems can be connected through their outputs only with the others from lower levels

Moreover only the hierarchical systems without, external factors (e.g. external controls) affecting particular subsystems (except for the subsystem from the highest level) are examined

It. is shown that for some global identification quality criteria, some structures of interconnections between individual subsystems in the system identified, and for some forms of models assumed for individual subsystems, the problem considered can be reduced to several identification problems of complex systems with cascade structure. The optimal solution of these problems based on the dynamic programming method is discussed.     

Optimal periodic control problem: a modified trigonometric approximation and quasi-stationarity conditions

The constrained optimal periodic control problem for a system described by differential equations and endowed with inertial controllers is considered, A sequence of discretized problems using trigonometric polynomials is proposed to approximate the problem. Instantaneous constraints for the state and control are handled by a new and more precise approach that imposes only a small number of non-linear but easily computable constraints. The convergence conditions for a sequence of optimal solutions of discretized problems are derived. The inclusion in the approximating scheme of various quasi-stationarity conditions for the control and state variables is analysed. Extension of a new approximating approach for inertialess and smooth problems is also discussed.     

ION EXCHANGE BEHAVIOUR OF 23 ELEMENTS AND AMPHOTERIC PROPERTIES OF CHELATING RESIN DUOLITE ES 346 CONTAINING AMIDOXIME GROUPS

Distribution coefficients of 23 elements between chelating resin Duolite ES 346 containing amidoximo groups and glycine - HCl buffer /pH = 2 - 3.5/, acetate buffer /pH = 3.6 - 5.6/ and HCl solutions /0.05 - 12M/ respectively were measured by batch equilibration at tracer loadings. While alkali and alkaline earth metals are practically not retained by the resin, transition and other metal ions show quite differentiated pattern of selectivity. The resin exhibits amphoteric properties and in certain conditions both cations and anions can be simultaneously adsorbed. Selectivity reversal for some pairs of metal ions can be achieved employing either cation exchange or anion exchange function of Duolite ES 346. Quantitative separations of Zn-Fe, Cd-In, Zn-Hg, Co-Cu, Zn-Re-Ga and Pt-Pd mixtures with the use of short columns of the resin have been demonstrated.     

Influence of niobium and molybdenum addition on microstructure and wear behavior of laser-borided layers produced on Nimonic 80A-alloy

Laser alloying was used for production of thick layers on surface of Nimonic 80A-alloy. For laser surface modification, three types of pre-coated pastes were applied: with amorphous boron, with amorphous boron and molybdenum as well as with amorphous boron and niobium. The microstructure, hardness and wear resistance of produced layers were studied in details. The presence of different types of borides in re-melted zone depended on the paste composition and caused an increase in hardness up to about HV 1000. The wear resistance was evaluated by calculation of mass wear intensity factor I_mw and relative mass loss of specimen and counter-specimen. The wear behavior of the tested frictional pairs was determined by 3D interference microscopy, scanning electron microscopy equipped with EDS microanalyzer. The significant increase in abrasive wear resistance was observed in comparison to untreated Nimonic 80A-alloy. The lowest mass loss intensity factor was characteristic of laser-alloyed Nimonic 80A-alloy with boron and niobium (I_mw=1.234 mg/(cm²·h)). Laser alloyed-layers indicated abrasive wear mechanism with clearly visible grooves. Laser alloying with boron and niobium resulted in the additional oxidative wear mechanism. In this case, EDS patterns revealed presence of oxygen on the worn surface of specimen.     

Miniature Detonating Cord (MDC) for Breaking Organic Glass Plates（英）

In order to develop a method to break the aircrafts canopy,a miniature detonating cords (MDC) of 1 mm in diameter were manufactured and its detonation properties were studied.MDC in a heavy lead confinement were also manufactured and were examined for breaking of organic glass plates.Results showthat MDC in lead confinement with 1g plastic explosive per metre,cuts organic glass plate 10 mm thick.     

Trigonometric approximation of optimal periodic control problems

Trigonometric polynomials are used to approximate the state trajectory, the control and the functions in differential equations and in the criterion of the constrained optimal periodic control problem. Several discretized problems using such polynomials are proposed to approximate the problem considered. Sufficient conditions for the convergence of solutions of approximating problems to the optimal solution of the basic problem are given. The application to a class of optimal periodic control problems in chemical engineering is discussed.     

Regularized trigonometric approximation of optimal periodic control problems

The optimal periodic control problem with the main and the additional optimality criterion for a system described by differential equations is investigated. The energy and raw material consumption are considered as the additional criteria. The problem characterized is approximated by a sequence of discretized optimization problems using trigonometric polynomials and penalty functions. Sufficient conditions are given for the convergence of solutions of discretized problems to the regular optimal solution, which minimizes the additional criterion over the set of solutions minimizing the main criterion. Strong convergence in the case where the energy consumption is the additional criterion is proven.     

Comments on ‘Eigenvalue assignment by unity rank output feedback’

Some formal mistakes in a paper of Hanmandlu and Shantaram (1987) are pointed out. Restrictions on the solution of the assignment problem using unity-rank output feedback are presented.     

MASS TRANSFER TO THE FREE INTERFACE IN STIRRED VESSELS

Liquid-phase mass transfer coefficients between gas and a flat liquid interface in a stirred tank are proportional to the average rate of energy dissipation raised to the power of one third for water and one quarter for organic solvents. This discrepancy can be attributed to the presence of surface active contaminants in aqueous systems. The critical value of the Reynolds number for the transition between the regime controlled by the small scale turbulence to that controlled by large scale eddies is about 100. The Levich-Davies model was found inappropriate in this case.