Determination of kinetic parameters for a pyrotechnic mixture

A general approach is considered to covering formally kinetic parameters from experiments for ignition, firing, or combustion of condensed substances based on minimizing discrepancies in experimental and calculated values. Results are provided for determining kinetic constants of a pyrotechnic mixture from data of firing it by a heated surface at a constant temperature.Leningrad. Translated from Fizika Goreniya i Vzryva, Vol. 27, No. 4, pp. 79–84, July–August, 1991.     

Aerosol-Generating Pyrotechnic Compositions with Components Interacting in the Combustion Wave

Observations were performed of the burning surface of the pyrotechnic aerosol-generating KNO₃/melamine/iditol system. Its effectiveness in suppressing a diffusion hydrocarbon flame and the quantity of the combustion residue were measured. An extremal dependence of the flame suppression effectiveness on the KNO₃/melamine ratio was obtained. The maximum effectiveness corresponds to the disappearance of the melt from the burning surface. This is due to the formation of nonmelting organometallic compounds in the combustion wave. The maximum flame-suppression effectiveness is achieved when the entire metal of the oxidizer is involved in the reaction. Possible versions of such reactions are discussed. Examples of calculation of optimal compositions of this type are discussed.__________Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 3, pp. 86–89, May–June, 2005.     

The effect of heat and mass addition on the base pressure of bodies of revolution at supersonic speeds

The results of an experimental investigation of the influence of mass addition and afterburning of combustion products of pyrotechnic mixtures in the base region of axisymmetric bodies in supersonic air flow at Mach numbers of 1.2–3.0 are reported. It is shown that the base-pressure increment increases monotonically to a maximum value with an optimum injected-mass flow rate. The value of this increment reduces as the Mach number decreases. A dependence generalizing the experimental data is presented.Translated from Fizika Goreniya i Vzryva, Vol. 32, No. 3, pp. 107–112, May–June, 1996.     

A mathematical model of the fusion of polymeric materials in extruders. Effect of polymer physical properties and processing regimes on rate of fusion

Conclusions The effect of polymer physical properties, rate of extruder screw rotation, and preliminary heating of the polymer on its rate of fusion have been studied.It has been shown that in individual sections of the interface a freezing of previously melted polymer takes place.The rate of polymer fusion along the screw channel is not constant, and as the flake moves from the inlet pipe of the extruder to the exit pipe, it initially decreases, then rises, and then drops again.Translated from Khimicheskie Volokna, No. 6, pp. 46–48, November–December, 1984.     

Explosion resistance of welded cylindrical titanium shells

Results are provided for an experimental study of the reaction to internal explosive loading of titanium alloy PT-3V welded cylindrical shells filled with air or water. It is established that shell failure develops a strong scale effect in the form of a sharp reduction in explosion resistance with an increase in dimensions. Recommendations are made for weakening the effect of the scale factor and increasing shell explosion resistance. Semi-empirical equations are obtained which are recommended for evaluating explosion deformation parameters for the shell of a cylindrical explosion protection chamber made of titanium alloy.VNIIÉF, Arzamas-16 607200. Translated from Fizika Goreniya i Vzryva, Vol. 30, No. 4, pp. 148–156, July–August, 1994.     

Oxidative carbonylation of methanol to dimethyl carbonate over CuCl/SiO2–TiO2 catalysts prepared by microwave heating: The effect of support composition

Copper(I) chloride catalysts with a loading of 20 wt%, supported on silica–titania mixed oxides with Si/Ti ratios of 1, 5, 10 and 50 were prepared by conventional and microwave heating methods and tested in the oxidative carbonylation of methanol to dimethyl carbonate (DMC). X-ray diffraction (XRD), nitrogen adsorption, X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA) were used to examine the bulk and surface properties of the CuCl/SiO₂–TiO₂ catalysts. Quantum-chemical calculations were performed to explore the interaction of CuCl with the silica–titania support. Microwave heating showed some significant advantages over the conventional heating method, with markedly reduced preparation temperature and time, and provided improved catalytic activity in the oxidative carbonylation of methanol. The catalytic behavior of CuCl/SiO₂–TiO₂ in the test reaction studied was strongly dependent on the support composition. Incorporation of tetrahedral Ti(IV) species into the silica matrix could enhance the interaction of copper species with the oxide support. The improved catalytic performance of CuCl/SiO₂–TiO₂ in the DMC synthesis can be understood by the existence of the strong coordination interactions between the Cu⁺ centers of CuCl and the bridging oxygen atoms at the Si–O–Ti bonds in the silica–titania support.     

Temperature limit of the metastable state of chemically unstable condensed materials

The results of determining the permissible heating of chemical unstable compounds obtained by different methods are found to be comparable. The importance of correct use of existing and new terminology is emphasized.D. I. Mendeleev Moscow Chemical-Engineering Institute, 125190 Moscow. Translated from Fizika Goreniya i Vzryva, Vol. 30, No. 3, pp. 59–62, May–June, 1994.     

Aluminophosphate bonded refractory mortars

Conclusions Chamotte mortars containing aluminophosphate bonds considerably improve the strength of the joint between firebrick refractories after heating to 400–800°C compared with mortars based on Portland cement and water glass. The highest strength for the mortar-firebrick bond is provided with a phosphoric acid density of 1.42–1.43 g/cm³ (60% phosphoric acid), and incorporating 20% bond in the mortar.It is possible to increase the strength of the chamotte mortar containing aluminophosphate bond during air setting and during heating, and also to increase the strength with time, by adding active materials to the mortar.Aluminophosphate-bonded mortar markedly increases the strength of the refractory-metal bonding, which is very important in building linings which are subject to movement during operation for example, in rotary kilns. It is desirable to test mortars containing aluminophosphate bonds in rotary kilns, and also in similar plant in the refractories, ceramic, and cement industries.Translated from Ogneupory No. 1, pp. 37–42, January, 1971.     

Electrolytic oxygen evolution on Ni-Co-P alloys

Electrolytically obtained Ni–Co–P alloys exhibit amorphous structure. On heating these alloys to 773 K crystalline nickel and cobalt phosphide phases, and also nickel crystallites, are formed. After cathode-anode polarization of the amorphous and crystalline Ni–Co–P alloys in 5m KOH for 18 h, oxygen-cobalt compounds together with crystalline or amorphous nickel phosphides appear on the electrode surface. The evolution of oxygen from 5m KOH was studied on Ni–Co–P alloys prepared in this way. The Tafel parameters were determined and it was ascertained that the values of directional coefficients of the Tafel lines are comparable with those obtained for spinel NiCo₂O₄ oxides, while calculated values of the exchange currents for the oxygen evolution reaction are dependent on the chemical composition of the alloy. The rate of electrolytic oxygen evolution is virtually identical for amorphous and crystalline Ni–Co–P alloys of the same chemical composition. The highest rate of oxygen evolution was found for the alloy containing 15–20% Ni, 66–73% Co and 12–14% P.     

浅谈Ⅲ类压力容器设计

根据多年设计经验提出了Ⅲ类压力容器设计时需注意的几点问题,如焊接接头系数、焊接接头型式、无损检测要求和管法兰型式等,并给出了相应的设计方案。介绍了压力容器风险评估报告的编制内容和方法。最后结合工程设计实例对提出的设计要点进行具体说明,为同类压力容器设计提供了参考。     

Orientation of poly(ethylene terephthalate) in high-speed spinning using a heating zone

Data on high-speed spinning using a heating zone were analyzed. It was shown that in spinning at a speed of 3500–4000 m/min using a heating zone, it is possible to attain high orientation corresponding to the level of ultrahigh-speed spinning at 7000 m/min.All-Russian Scientific-Research Institute of Synthetic Fibres. Tver' Translated from Khimicheskie Volokna No. 3. pp. 4–6. May–June. 1966.     

Corrosion resistance of welded Kh17N13M2T steel in aggressive media from production of Nitron (polyacrylonitrile) fibre

Conclusions 1. Scale, formed when welding Kh17N13M2T steel, causes discolouration of sodium thiocyanate solutions and this cannot be tolerated in Nitron fibre production.2. Joints, welded both by argon-arc and by electric-arc welding, can be freed completely of scale by chemical cleaning.3. No corrosion pitting was observed at the heat-affected zone with argon-arc welded joints which had been chemically cleaned.4. It is important to check for possible intercrystalline corrosion of the steel. This may occur with equipment operating in solutions of sodium thiocyanate (GOST 6032-58).Titanium steel with 17% Cr, 13% Ni, and 2% Mo.All-Union Scientific Research and Design Institute of Chemical Machinery Construction (NIIKhIM-MASh). Translated from Khimicheskie Volokna, No. 5, pp. 60–62, September–October, 1969.     

The growth and composition of layers of slags of the system CaO-Al2O3

Conclusions The conditions for the formation of a slag layer in an unlined and uncooled steel pipe were determined by methods of mathematical experiment design and on hot models.Within the investigated limits of variation of the factors the growth of the layer is governed by the degree of excess heating of the slag and its stay time in the pipe. The results of calculations of the thickness of the layer from the mathematical model constructed for this purpose agree very closely with the results of the industrial-scale experiment.An analysis of the mineral composition and melting point of four slags of the system CaO-Al₂O₃ showed that among the compositions investigated the slag lining approaching the composition of CaO-Al₂O₃ possesses the best combination of properties.Translated from Ogneupory, No. 7, pp. 58–64, July, 1976.     

Oxidation efficiency in the electro-Fenton process

An electro-Fenton treatment of a solution containing phosphorus compounds using a graphite electrode is described. Different operating conditions are tested to investigate the influence of the reagent ratio on the oxidative efficiency. Results show that electro-Fentons reagent is able to provide a powerful conversion of the phosphorous compounds into phosphate. As hydrogen peroxide is continuously provided by the cathodic reduction of oxygen, the crucial step appears to be the iron dosage whose optimal concentration is found in the range 50–150 mg l^–1. Quantitative oxidation is not reached for concentration lower than 50 mg l^–1. Nonetheless, an excess of both iron and hydrogen peroxide in the bulk is found to negatively affect the oxidation yield because of the occurrence of undesired side reactions.     

Chemical transformations in high-temperature treatment of polyacrylonitrile fibre (review)

Possible compounds separated from the heteroaromatic structure of oxidized PAN fibre during its high-temperature treatment were analyzed with the data on the change in the chemical composition. It was shown that a reaction involving hydroxyl and carbonyl groups in neighboring chains is the most probable reaction in the initial stage of intermolecular polycondensation. The proportions of structures with different degrees of condensation and the change in them with an increase in the treatment temperature in a wide range of heating rates were investigated. The nonsimultaneous character of the chemical transformations in the entire PAN fibre related to the different mobility of segments of the polymer chain in heat treatment of the fibre in air was demonstrated.Avtor Scientific-Production Association, Mytishchi. Translated from Khimicheskie Volokna, No. 1, pp. 18–24, January–February, 1994.     

Device for infrared heating of moving synthetic yarns

Conclusions As a result of these studies, the types of yarns for which IR heating is more promising as compared with heating methods have been determined.The mechanism of interaction of IR radiation energy with the yarn system has been studied.Basic constructional elements of IR devices of the vertical and horizontal types have been determined.Results have been given from studies of various yarns in the IR and contact methods of heating.Translated from Khimicheskie Volokna, No. 6, pp. 35–37, November–December, 1989.     

铂重整加热炉炉管的焊接与标注

介绍了铂重整加热炉U型炉管的焊接与焊缝标注方法。对焊接、检验人员及炉管和焊材必须有专门的要求 ,应建立相应的施焊管理制度。所有焊缝均应进行热处理、X射线探伤和硬度测定 ;施焊位置应标注炉管号、焊缝号、焊工号。     

Hydrothermal Synthesis of Leucite and Its Application in Engineering Ceramics

The conditions for producing tetragonal and cubic leucite from tetragonal analcime by hydrothermal ion exchange in an alkaline medium are identified. The process parameters are specified. A composite ceramic material based on cubic leucite is developed for the heating elements of plants for vacuum synthesis of pure inorganic compounds.__________Translated from Steklo i Keramika, No. 2, pp. 21 – 24, February, 2005.     

Open-flame application of refractory coatings

Conclusions An analysis was carried out of the heating of particles in the flame cone of a gas and oxygen burner.The powder particles are heated almost to the temperature of the flame cone provided their concentration is less than 3 · 10^–4 m³/m³.The particles of a low-melting additive are spheroidized in the flame cone while those of the refractory filler (magnesite) are fused to a certain extent.The molten particles of the additive do not usually break up in their flight through the flame cone. The solid and liquid particles form conglomerates measuring 150–200 in diameter.Magnesite loss reaches 40.5–49% in the application process. The open porosity of the coating varies 3–9% depending on the type of additive. The strength of the adhesion of the coating to periclase — spinel brick varies 20–50 kg/cm².Translated from Ogneupory, No. 4, pp. 30–36, April, 1976.     

Investigation of the oxidation kinetics of silicon carbide heaters

Conclusions In the range 1200–1500°C the mechanism of oxidation of industrial heating elements containing 97–99% silicon carbide is approximately identical with, and is controlled in the same way, as the oxidation of pure silicon carbide [1, 2], in the main by oxygen diffusion through a film of SiO₂.The relationship between the oxidation of various silicon carbide heating elements and time is described the equation q=K^b, where b comes within the range 0.3–0.5. The relationship between the oxidation rate of the heating elements and the temperature obeys the Arrhenius equation: K=K₀exp(–E/RT).The calculated activation energy for the process for various heating elements alters from 23 to 43 kcal/mole.The porosity of the heaters (up to values not exceeding 18%) substantially affects the oxidation capacity.Translated from Ogneupory, No.6, pp. 52–57, June, 1970.