PRACTICAL APPROACHES TO PREVENTION OF FIRES IN RESIDENTIAL BUILDINGS DUE TO VIOLATION OF RULES OF INSTALLATION AND OPERATION OF FURNACE HEATING

В статье анализируется динамика количества пожаров, происходящих вследствие нарушения правил эксплуатации и установки печного оборудования, количество травмированных и погибших в результате пожаров в жилом секторе. Рассматриваются основные нормативные правовые акты, действующие на территории Российской Федерации в области установки и эксплуатации печного оборудования. Сформулированы основные правила эксплуатации печного оборудования в жилых домах. The article analyzes the dynamics of number of fires caused by violation of rules of operation and installation of furnace equipment. And also there are analyzed the number of injured and dead as a result of fires in the residential sector. There are considered the main regulatory legal acts in the field of installation and operation of furnace equipment on the Russian Federation territory. The basic operating rules of furnace equipment in residential buildings are formulated.

Теплофизические характеристики теплозащитного материала корпуса ракетного двигателя при температурах до 1000 оС

An experimental determination of the temperature dependences of the specific heat capacity and the thermal conductivity coefficient of the multifunctional coating MFP-92 at temperatures up to 1000 °C has been carried out. At temperatures up to 450 °C, an IT-c-400 device was used to determine the specific heat capacity. IT-l-400 device was used for the determination of thermal conductivity. At higher temperatures, the determination of the thermophysical characteristics (TPC) was carried out by solving the inverse problem of thermal conductivity (IPT) in a flat plate under conditions of one-sided heating in a muffle furnace. Composite material MFP-92 is a multilayer structure with upper layers based on silica fabric and chromophosphate binder and lower layers based on mullite-silica fabric and aluminosilicate binder. The TPC of the layers also differ from each other, and, accordingly, the properties of this material as a whole can be determined only in the form of their effective values, averaged in one way or another over the thickness of the coating. In addition, during heating, the material undergoes significant physicochemical transformations associated with the thermal destruction of its components, manifested in the form of abundant gas release, and a decrease in the density of the material, which significantly changes its TPC and determines its dependence on the heating rate. Therefore, studies of the thermophysical characteristics of the MFP-92 material were carried out with several (2-5) consecutive heating cycles. It was found that in four heating cycles of the MFP-92 material up to 450 °C for 75 minutes when measuring the specific heat on the IT-c-400 device, its temperature dependence significantly changes qualitatively and quantitatively. With furnace heating to 1000 °C, the temperature dependences of the TPC of the material, determined in the first and second heating cycles, have a different form, but change insignificantly in subsequent heating cycles. This makes it possible to ascribe to the MFP-92 material a set of two sets of TPC related to its initial (phase A) and annealed after heating to 1000 °C (phase B) states. Using the obtained TPС of phase A (including the magnitude of the thermal effect of irreversible endothermic phase transition at 100 °C) and phase B, good agreement was obtained between the calculated and experimental temperature fields in the samples under furnace heating conditions.

Features of structure formation of surface layers with high content of boron on steel 15Х11МФ in the conditions of furnace and induction heating

The results of obtaining borated layers on 15H11MF high-alloy steel under equilibrium and non-equilibrium heating conditions are presented. Equilibrium conditions were achieved by slow furnace heating (with a heating rate of 0.1 oC/s), non-equilibrium – by induction heating (with a heating rate of 100 oC/s). The heating was controlled by measuring the thermoelectric power by a thermocouple welded to the surface of the sample by electric contact welding. The signal from the thermocouple was digitized by the ADC and transmitted to a computer where, at high speed, an array of data of temperature-time dependence of the process was formed. Furnace heating was carried out in a laboratory electric furnace at 1130 оС ± 5 оС, 1150 оС ± 5 оС and 1160 оС ± 5 оС. Induction heating was carried out to temperatures of 1180 oC ± 20oC, 1200 oC ± 20oC, 1220 oC ± 20oC. The possibility of significant reduction of the treatment process from 3 hours to 2 minutes due to the intensifying action in non-equilibrium conditions of structure formation is shown. Boron saturation came from the paste. Saturating paste consisted of 60% boron carbide, 30% NaF, 10% CaF2. The method of metallographic research shows not only the morphological differences of the obtained surface layers, but also established the predominant mechanism of boron diffusion into high-alloy martensitic steel. During furnace heating (1150оС), a solid boron with a thickness of up to 50 μm and a hardness of 15100 MPa is formed. At a depth of up to 150 μm, grain boundary diffusion is noticeable, which obviously dominates in the processes of boron saturation of high-alloy steels. At temperatures of 1160 oC and furnace heating under a solid layer of boride with a thickness of 110 μm, a two-phase zone is formed, which consists of boride and a solid solution with a thickness of 70 μm. This layer is more defective. Induction heating with boron saturation forms a thick (up to 200 μm) layer of coarse boride crystallites (18900 – 9270 MPa) with an eutectic structure (6440 MPa), which becomes coarser with increasing temperature from 1180 to 1220 оС. The ability to obtain solid hardened layers in a short treatment time makes boron saturation from pastes a more attractive alternative among other chemical-heat treatment technologies.

Heat-Treatment of Aluminium-Nickel Composite Cold Sprayed Coating

Intermetallic compounds, especially aluminides, show good high-temperature strength, oxidation resistance, high melting points, and thus have received considerable attention as potential substitutes for superalloys in high-temperature applications. Aluminides are especially interesting because they are stable up to the critical temperature of ordering, which is close to the melting temperature. In the Al-Ni system, the most studied intermetallics are Ni3Al, NiAl and NiAl3. In the presented study, Al and Ni powders were mixed together with Al2O3 in various proportions to produce dense coatings by low-temperature cold spraying. Two types of post-deposition treatments were applied to produce aluminides, namely furnace heating and resistance spot welding. The former caused a long time diffusion while the latter a self-propagating high temperature synthesis. Both heating methods enabled formations of intermetallic phases. However, the furnace heating provides high porosity. The microstructure of the samples was analyzed by SEM (scanning electron microscope), EDS (energy dispersive X-ray spectroscopy) and XRD (X-ray diffraction) together with microhardness measurements.

Natural magmatic granite as matrix for immobilizing simulated An4+ waste

In nature, many rocks contain radionuclides, and returning radioactive waste to nature is an environmentally friendly way. In this work, a natural magmatic granite rock has been studied as a host matrix for simulated An4+ waste disposal. The blank granite, in the form of powder, was firstly treated by muffle furnace heating in the temperature range of 800 °C to 1400 °C. It was found that the lowest crystallinity of the samples was obtained at 1300 °C. Moreover, 8 wt.% of simulated tetravalent actinides (CeO2) could be successfully immobilized in the natural granite at 1300 °C for 60 min. Raman results show the structure disordering in samples tends to increase with the increased amount of CeO2. SEM-EDS observation shows that the distribution of Ce was relatively uniform in the matrix. Moreover, the hardness of solidified body is comparable to traditional glasses and it decreases with the increase of CeO2 content.