Molecular weight distribution in cellulose triacetates and its effect on the mechanical properties of fibres

Conclusions 1. A precise method is defined for determination of the molecular-weight distribution of the original cellulose acetate by fractional precipitation of 1% methylene chloride solutions of the TAC in ethanol.2. A method is developed for quantitative determination of low-molecular fractions which is based on extraction of the polymer from a mixture of methylene chloride and ethanol at 25°C with addition of ammonium thiocyanate.3. The dependence of the physical and mechanical properties of triacetate fibres on the average molecular weight of the polymer is demonstrated.Tashkent Institute for Textiles and Light Industry; HIIKhTTs MKhP SSSR, Tashkent; Kaunas Factory. Translated from Khimicheskie Volokna, No. 5, pp. 48–50, September–October, 1969.     

Polymorphism of Alpha-Synuclein Amyloid Fibrils Depends on Ionic Strength and Protein Concentration

Protein aggregate formation is linked with multiple amyloidoses, including Alzheimer‘s and Parkinson‘s diseases. Currently, the understanding of such fibrillar structure formation and propagation is still not sufficient, the outcome of which is a lack of potent, anti-amyloid drugs. The environmental conditions used during in vitro protein aggregation assays play an important role in determining both the aggregation kinetic parameters, as well as resulting fibril structure. In the case of alpha-synuclein, ionic strength has been shown as a crucial factor in its amyloid aggregation. In this work, we examine a large sample size of alpha-synuclein aggregation reactions under thirty different ionic strength and protein concentration combinations and determine the resulting fibril structural variations using their dye-binding properties, secondary structure and morphology. We show that both ionic strength and protein concentration determine the structural variability of alpha-synuclein amyloid fibrils and that sometimes even identical conditions can result in up to four distinct types of aggregates.     

A study of thermal conductivity of structural ceramic materials. Part I. State of research of thermal conductivity of structural materials

At the present time, experiment is a reliable method for studying the thermal conductivity of new ceramic materials and especially refractories. However, the range and possibilities of existing devices do not meet the requirements for measuring thermal conductivity, especially at a high temperature. At very high thermal loads under the conditions of formation of surface columnar crystal structures, thermoelastic stresses, disturbances in vibration of the elementary lattice, and other phenomena, the thermal conductivity can be a function of the temperature drop. The present paper concerns the physical fundamentals of heat conduction in current ceramic materials and refractories based on MgO, A1₂O₃, and Si₃N₄. The classical stationary and nonstationary methods for determining thermal conductivity are considered. Special attention is devoted high-temperature processes and the difficulties arising in this case. It is recommended to solve high-temperature problems by using methods based on solving inverse problems of heat conduction     

Application of walsh functions to construct an explicit projection algorithm for identification of distributed systems

High interference-immunity and resolution are obtained for an explicit projection identification algorithm that is realized easily on an electronic computer.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 5, pp. 840–845, May, 1988.     

Concentrated polymer emulsion based on cellulose triacetate and polycarbonate

Conclusions The cellulose triacetate-polycarbonate emulsion polymer system has been investigated.It has been found that CTA-PC solutions are less structured systems and are characterized by lower values of effective viscosity and apparent activation energy of viscous flow as compared with CTA solutions, which affords the possibility of raising the concentration of a spinning solution to 21% by wt.It has been shown that the physicomechanical properties of fibres and yarns have a tendency to become increased, thereupon the resistance to abrasion rises 2.5-fold.The CTA-PC polymer emulsion presents interest from the point of view of developing a method for the preparation of dull yarns.Translated from Khimicheskie Volokna, No. 5, pp. 45–47, September–October, 1988.     

A linearly variable high-voltage amplifier

A principle of operation and schematic diagram of a linearly variable (triangular pulses) high-voltage amplifier with a 300-gain and 1000-V maximum output voltage is described. The amplifier is intended for a system for prompt monitoring of voltage-capacitance characteristics and leakage currents of high-voltage semiconductor devices and products with dielectric layers.