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Abstract
A bibliometric study based on worldwide scientific and technical publications on refractory materials used in iron and steelmaking processes during 1980–87, has been carried out. Six bibliographic databases were searched and from them 2464 references were retrieved. The highest percentage of published documents were journal articles (60%), followed by patents (33%). The core journals areOgneupory (USSR) andTaikabutsu (Japan). The USSR was by far the most productive country, both in number of published papers and in number of journal titles devoted to the subject. In The Soviet Union research work is mainly carried out in universities and institutes of the Academy of Sciences. On the other hand, Japan is the most productive country in patent registered, and research work is carried out there either in private refractory companies or in steelmaking enterprises. The trend in worldwide research points towards shaped refractories, particularly based in high alumina, magnesia, zircon carbides and mixtures containing oxides and carbon, which are largely used in converters, transport ladles and continuous casting processes.
Abstract
The thermal degradation behavior of P. halepensis needles treated with two ammonium-polyphosphate-based commercial retardants was studied using thermal analysis (DTG) under nitrogen atmosphere. Moreover, for the same experimental material, the heat of combustion of the volatiles was estimated based on the difference between the heat of combustion of the fuel and the heat contribution of the charred residue left after pyrolysis. The heat of combustion of the volatiles was exponentially related to the retardant concentration of the samples. In the range of retardant concentrations from 10 to 20% w/w the mean reduction percentage of the heat of combustion of the volatiles, with respect to untreated samples, was 18%.
Abstract
Fire resistance of polyethylene is realized by magnesium hydroxide which is distinguished from halogenated fire-proofing agents by its lower cost and its non toxicity. Magnesium hydroxide decomposed by an endothermic reaction with liberation of water, contributing to fire proofing. The sample used (Kisuma 5A-N*) is constituted from a powder (0.6–0.8 micrometre) its surface is treated by plastic material in order to ameliorate its compatibility. We studied the thermal decomposition by DTA and TG, of mixtures constituted by polyethylene and magnesium hydroxide. A sudden decomposition began at 385°C for pure polyethylene and decomposition took place at 429°C for the mixture polyethylene-Kisuma (50–50). Incorporation of magnesium hydroxide in polyethylene increases fire resistance.
Abstract
The thermal decomposition of a polypropylene film, a polyurethane adhesive, as well as a polypropylene coated with a polyurethane adhesive have been studied by a thermogravimetric (TG) analysis, at a heating rate of 5°C a minute with air flow. During the thermal analysis different decomposition steps which correspond to different weight loss rates were obtained on thermal curves. Gases were collected between the different decomposition steps and then analyzed. The results reported deal with the conversion of carbon into oxides and aldehydes—ketones, and also with that of nitrogen into hydrogen cyanide and isocyanates. The findings lead to a better understanding of the hazards and risks of toxic emissions that may be generated by the gas formation following heating of these materials.