Analysis of Extraction Separation in a Cascade of Mixing-Settling Extractors in a Recirculation Liquid-Liquid Chromatography Mode

Theoretical Foundations of Chemical Engineering - Previously, a method for increasing the efficiency of extraction separation of liquid mixtures has been proposed, in which a solution of a mixture...     

Nanoscale Nickel-Containing Powders for Use in CO and NO2 Gas Sensors

Russian Journal of Non-Ferrous Metals - This paper investigates the physicochemical characteristics and gas-sensitivity mechanisms of nickel oxide (NiO) and nickel ferrite (NiFe2O4) obtained by...     

Electron-Quantum Transport in Pseudomorphic and Metamorphic In0.2Ga0.8As-Based Quantum Wells

Semiconductors - Metamorphic high-electron-mobility transistor (HEMT) structures based on deep In0.2Ga0.8As/In0.2Al0.8As quantum wells (0.7 eV for Γ electrons) with different metamorphic...     

Effect of laser treatment on the wear resistance of steels

It is known that laser hardening increases the wear resistance of friction parts quite substantially. At the same time, many problems connected with the effect of the treatment process and the special features of laser hardening on the characteristics of wear resistance require detailed consideration. The present paper is devoted to the development of recommendations on choosing the optimum location and proportion of the areas of the hardened and unhardened regions of the surface of structural steels after their treatment with radiation of a continuous CO₂ laser. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 10, pp. 10–12, October, 1998.     

Origins of robust control: Early history and future speculations

A revolution in control theory thought happened in the early 1970s when the dominant focus of research shifted from optimality to robustness in response to unexpected failures of optimal control theory to produce feedback control designs capable of tolerating normal differences between design models and reality. The robustness concept has since become such an integral part of present day control theory that it is difficult to imagine that time long ago when the concept lacked a clear mathematical representation and the tools of multivariable robustness analysis were yet to be identified. We shall revisit that time to examine the events that facilitated, and necessitated, this remarkable paradigm shift. Next, looking to the future, we will consider how failures of robust control designs to cope with incorrect uncertainty estimates are beginning to spur control theorists to consider data-driven problem formulations for estimation and control that tacitly question the roles of basic concepts like true model and uncertainty bounds, stochastic noise models and even Bayesian probability. We will discuss how and why Karl Popper’s scientific logic of unfalsification seems to be emerging as a central concept in these data-driven problem formulations, and how the unfalsification concept might again shift the focus of mathematical research in the areas of estimation and control.     

Effect of Chitosan on the Efficiency of Dyeing Textiles with Active Dyes

It was shown that incorporation of chitosan in the dye bath in dyeing textiles made from cotton fibres with active dyes increases the intensity and strength characteristics of the color. The optimum concentrations of chitosan and other dye bath reagents that maximally increase the color intensity are determined.     

Electrical Properties of the Nb<Subscript>2</Subscript>O<Subscript>5</Subscript>-NiO System

The electrical resistivity of Nb₂O₅-NiO materials was measured in the range 20-500°C. The resistivity of the samples was found to be sensitive to the presence of ammonia or sulfur dioxide in air. Some of the oxides in the Nb₂O₅-NiO system are potentially attractive as materials for temperature and gas sensors.