The Importance of Long-Term Observations in Assessing the Strength of Polycaproamide Fibre

According to long-term observations, rewinding and slubbing operations have almost no effect on the unit strength of complex and slubbed polycaproamide fibres but affect the relative elongation at break. The stability of the deformation-strength properties of the fibres in time, assessed with the values of the coefficients of variation, during the manufacturing process, including slubbing, improves significantly. The fibre strength is not a function of fluctuations in the content of low-molecular-weight compounds in the initial polymer and its relative viscosity, spinning temperature, and elementary fibre thickness in the undrawn fibre in contrast to the moisture content of polymer going to spinning and the degree of orientational drawing of the fibre.     

High-temperature catalysts with a synergetic effect of Pd and manganese oxides

A synergetic effect in the catalytic activity has been found after palladium introduction in Mn–Al–O systems. The magnitude of the synergetic effect depends on the types of the oxidic manganese species: oxide Mn₃O₄, spinel (Mn, Mg)[Mn, Al]₂O₄ or hexaaluminate (Mn, Mg)LaAl₁₁O₁₉. The synergetic effect of Pd and manganese-containing compounds is observed only if palladium is introduced to the low-temperature precursor of the manganese alumina spinel or manganese hexaaluminate. The synergetic effect is not observed when high-temperature samples with formed spinel or hexaaluminate phases are modified with Pd.     

Self-Propagating High-Temperature Synthesis of Cerium Chromite Substituted with Alkaline-Earth Metals

Cerium chromites, non-substituted and substituted with alkali-earth metals, are synthesized in the self-propagating high-temperature synthesis mode using solid interaction oxidizes. The characteristic temperatures and specifics of interaction between the components are determined for all systems considered. The structural and physicochemical parameters, including the spectroscopic characteristics of the synthesis products depending on the alkaline-earth metal substituent and the degree of substitution, are investigated.     

Numerical Simulation of Ignition of a Condensed Substance by a Particle Heated to High Temperatures

The problem of ignition of a condensed substance by single particles heated up to high temperatures is solved within the framework of the twodimensional heattransfer model. Numerical studies are performed for typical materials: polyvinyl nitrate and carbonic particles. Regimes of ignition of a condensed substance by a single particle at relatively low temperatures are adequate in terms of the ignition delay to regimes of heating of the condensed substance by a gas flow without particles; at high temperatures, they correspond to regimes of heating by a metal plate with a fixed temperature. In a certain (rather narrow) range of particle temperatures, the use of the twodimensional heattransfer model yields ignitiondelay values substantially different from other regimes.     

Biclustering meets triadic concept analysis

Biclustering numerical data became a popular data-mining task at the beginning of 2000’s, especially for gene expression data analysis and recommender systems. A bicluster reflects a strong association between a subset of objects and a subset of attributes in a numerical object/attribute data-table. So-called biclusters of similar values can be thought as maximal sub-tables with close values. Only few methods address a complete, correct and non-redundant enumeration of such patterns, a well-known intractable problem, while no formal framework exists. We introduce important links between biclustering and Formal Concept Analysis (FCA). Indeed, FCA is known to be, among others, a methodology for biclustering binary data. Handling numerical data is not direct, and we argue that Triadic Concept Analysis (TCA), the extension of FCA to ternary relations, provides a powerful mathematical and algorithmic framework for biclustering numerical data. We discuss hence both theoretical and computational aspects on biclustering numerical data with triadic concept analysis. These results also scale to n-dimensional numerical datasets.     

Fast Simulation of the Functional Failure of an s – t-Network with Repair

An s – t-network with highly reliable edges with repair and variable external load is considered. A fast simulation method is proposed to evaluate the probability of functional failure when the real capacity of the network is less than the required capacity. It is proved that under some conditions the estimate has a bounded relative error as edges reliability increases. The numerical example illustrates the efficiency of the method.     

Development of Monolithic Catalysts with Low Noble Metal Content for Diesel Vehicle Emission Control

Monolith washcoated catalysts with potential for diesel emission control have been developed. Two types of catalysts have been prepared for further study: (1) MnO _x supported on granulated -Al₂O₃, (2) MnO _x supported on cordierite monolith washcoated with -Al₂O₃. Both catalysts have been calcined at 500 and 900 °C and subsequently modified by doping with 0.1–1.0 wt% of Pt or Pd. The influence of the concentration of both manganese oxide (0–10 wt%) and noble metals Pt and Pd in the range 0–1.0 wt% on the catalytic activity in methane oxidation has been studied. Comparison of the catalytic activity of MnO _x /Al₂O₃ and MnO _x + Pt(Pd)/Al₂O₃ with that of a standard 1 wt%Pt/Al₂O₃ catalyst shows the existence of a synergetic effect. This effect is more pronounced for the samples calcined at 900 °C. The developed monolithic catalysts MnO _x + Pt(Pd)/Al₂O₃ demonstrate higher activity and thermal stability (up to 900 °C) compared to the commercial monolithic catalyst (TWC's).     

Systems for automating technological processes of synthetic fibre and yarn preparation

Conclusions -- Some basic special features in devising a panel-free technology in the manufacture of synthetic fibres and yarns have been examined.-- Some advantages of an approach based on parallel designing of the technological process and the control system over the traditional approach have been shown.-- The new methodical approach has found application in developing automation systems at a number of synthetic fibre and yarn manufacturing plants.Translated from Khimicheskie Volokna, No. 5, pp. 47–48, September–October, 1990.