Unstable Oscillating Systems with Hysteresis: Problems of Stabilization and Control

Journal of Computer and Systems Sciences International - The work is devoted to studying the dynamics of unstable oscillating systems (in the form of an inverted pendulum) controlled by the action...     

Barrier refractory materials for aluminum electrolyzers based on concentrated Kampanovskii kaolin

The authors describe the results of developing compositions and technologies for barrier materials based on the products of concentration of kaolins from the Kampanovskii deposit for cathode lining in aluminum electrolyzes. High-density dry barrier mixtures with different Al₂O-SiO₂ ratios (from 0.42 to 0.76) have been obtained, which can be used in two-layer linings for aluminum electrolyzers (in the high-alumina and silica layers). The composition and properties of these mixtures correspond to known foreign analogs. __________ Translated from Novye Ogneupory, No. 11, pp. 36–40, November, 2006.     

Method of Solution of a System of Equations Describing the Continuous Process of Polymerization under Conditions of a Polyaddition Reaction

A method of solution of a system of equations which describe the continuous process of polymerization of butadiene on a cobalt catalyst accompanied by the polyaddition reaction is proposed. The moments of second and third orders as functions of the distribution of macromolecules by the degree of polymerization and the number of active centers in each reactor are compared. The values of the conversion of a monomer for which the moments go to infinity (which means gelation in the reactor) are determined. The solution is based on the replacement of variables which made it possible to reduce the equation of the fourth degree for the moments to a quadratic equation and to single out the branch corresponding to the actual process. The algebraic transformations and calculation were carried out with the use of the Matematika 3.0 package.     

Electrodialysis synthesis of concentrated solutions of perrhenic acid

The presented results demonstrate the possibility of electrodialysis production of concentrated solutions of perrhenic acid (HReO₄ concentration >400 g/l). KReO₄ is used as a precursor. The investigations are performed in a three-chamber electrodialysis cell in a continuous mode. The optimal processing parameters are as follows: the current is 3–5 A, the voltage is 30–40 V, and the anode chamber temperature is 20–25°C. Grade AR-0 ammonium perrhenate is precipitated from the obtained HReO₄ solution.     

Effect of temperature on the corrosion of some materials in perrhenic acid solutions

Corrosion of some metallic and nonmetallic materials (nickel, copper, iron, glass) in solutions of perrhenic acid HReO₄ (∼345 g/l) is studied in the temperature range 15–30°C. It is demonstrated that this process is limited by diffusion and characterized by the following values of activation energy (kcal/mol): 1.21 for glass; 1.77 for iron; 1.83 for copper, and 2.01 for nickel.     

Drug intolerance

The authors present experimental data on luminol-dependent neutrophil chemiluminescence of blood from patients with drug intolerance. A decrease in intensity of neutrophil and whole blood chemiluminescence was registered in the presence of intolerated drugs. In acute phase of generalized intolerance reaction the chemiluminescence test showed readiness of the blood cells to react inadequately to the contact with different drugs leading to variations in generation of active oxygen forms. Improvement in patients' condition was followed by narrowing spectrum of drugs causing a decrease in the intensity of the chemiluminescence. Later, the chemiluminescence ratio remained low in testing only those drugs causing intolerance reaction.     

Low-Temperature Transport Properties of Sn<Subscript>24</Subscript>P<Subscript>19.3</Subscript>Br<Subscript>8</Subscript> and Sn<Subscript>17</Subscript>Zn<Subscript>7</Subscript>P<Subscript>22</Subscript>Br<Subscript>8</Subscript>

We report on temperature-dependent thermal conductivity, resistivity, and Seebeck coefficient of two polycrystalline Br-containing Sn-clathrate compounds with the type I crystal structure. Interstitial Br atoms reside inside the polyhedral cavities formed by the framework, resulting in hole conduction. The framework bonding directly influences the transport properties of these two compositions. The transport properties of these two clathrates are compared with those of other Sn-clathrates. We also discuss our results in terms of the potential for thermoelectric applications.     

Tight risk bounds for multi-class margin classifiers

We consider a problem of risk estimation for large-margin multi-class classifiers. We propose a novel risk bound for the multi-class classification problem. The bound involves the marginal distribution of the classifier and the Rademacher complexity of the hypothesis class. We prove that our bound is tight in the number of classes. Finally, we compare our bound with the related ones and provide a simplified version of the bound for the multi-class classification with kernel based hypotheses.