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There are several types of carbon fibre materials (CFM) fabricated by carbonization of hydrated cellulose (HC) fibres. In particular, the following brands of CFM are manufactured at Khimvolokno Scientific and Industrial Association: UVK, Uglen, UUT-2, Ural (Viskum), etc. [ 1, 2]. These materials not only differ in textile form, but also in the final heat treatment temperature (HTT). Thermal decomposition of HC fibre raw material in the presence of a catalytic additive, which significantly affects the physicomechanical characteristics of the f'mal product (CFM), is the basic technology for their production.The analysis of the published data on thermal decomposition of HC fibres in the presence of different additives [3][4][5][6][7] suggests that when they are correctly selected, the yield of CFM can be increased to 28-30 wt. %, the physicomechanical characteristics of the CFM can be improved, and the duration of the heat treatment stage, and formation of active groups in the structure of the CFM can be decreased, etc. In this respect, we considered studies of the effect of inorganic additives on thermal decomposition of HC fibres to be urgent and of scientific and practical interest.We investigated the features of thermal decomposition of HC fibres in the presence of sodium triphosphate in the 20-900"C temperature region and with different concentrations (0.05-0.1 M) of additives by physicochemical methods. The advantages of using triphosphates as additives in thermal decomposition of polymer fibres consist of the following: Triphosphates, also known as tripolyphosphates, are nontoxic, do not degrade fibres of any type, are incombustible, and do not corrode the equipment used for carbonization.HC twist fibre from Mogilev Khimvolokno Industrial Association was used for our studies, and sodium triphosphate was used as the inorganic additive. The samples of HC fibre were impregnated with aqueous solutions of Na5P3010 of different concentration for 0.5 and 1 h, then the excess solution was squeezed out and the samples were dried in air. The dried samples of HC fibres were carbonized in the setup shown in the diagram in Fig. 1. The reaction of thermal decomposition was conducted in a quartz reaction vessel 2 in helium medium with a temperature elevation rate of 2~ to 400~ The temperature was subsequently increased to the given temperature at the rate of 3.3 ~The sample was then raised to the top of the reaction vessel, cooled to 80-90~ and the yield and strength characteristics of the f'mal product were determined [81.The temperatures in furnace 1 were monitored with chromel alumel thermocouple 3, and the temperature elevation rate was regulated with a RIF-107 instrument. The derivatograms were made on a Q-1500D instrument. Calcined aluminum oxide was used with ethanol. The reaction of thermal decomposition of samples of HC was conducted in a current according to the following method: weighed portions of samples of HC fibres (--0.25 g) were taken and placed in a platinum crucible, and the temperature was raised at the ...

The results of experimental study of three noncytopathic and two cytopathic bovine viral diarrhea virus (BVDV) strains isolated from cattle in the Siberian region and belonging to the type 1 (subtypes 1a, 1b, and 1d) have been presented. All investigated strains caused the development of infectious process in the seronegative 4–6-month-old calves after aerosol challenge with the dose of 6 log10 TCID50. The greatest virulence had noncytopathic strain and cytopathic strain related to the subtypes 1d and 1b, respectively. All strains in infected calves caused some signs of moderate acute respiratory disease and diarrhea: depression 3–5 days postinfection (p.i.), refusal to food, severe hyperthermia to 41.9°С, serous exudate discharges from the nasal cavity and eyes, transient diarrhea with blood, leukopenia (up to 2700 cells/mm3), and macroscopic changes in the respiratory organs and intestine. The infected animals recovered from 12 to 15 days p.i. and in 90% cases formed humoral immune response 25 days p.i. (antibody titers to BVDV: 1 : 4–1 : 16). Our results confirmed the presence of virulent BVDV1 strains and showed the need for researches on the molecular epidemiology of the disease, development of more effective diagnostic systems, and optimization of control programs with use of vaccines.