Production and use of periclase-chromite concrete parts for the linings of high temperature ladles

Conclusions A method has been developed for production of standard periclase-chromite concrete parts for the linings of high temperature ladles for teeming steel and ferroalloys. The parts have high strength and low porosity and are practically shrinkage-free.The life of periclase-chromite concrete parts in the steel teeming ladles of Chelyabinsk Metallurgical Plant is about four times greater than that of fireclay parts, in Red October Plant practically the same as that observed with the use of high alumina parts, and at Chelyabinsk Electrometallurgical Plant it was higher only in the upper portion of ladles in comparison with that obtained with the normally used fired periclase parts.During service in ladles the parts do not spall, become encrusted at a metal temperature of 1620 °C, do not become encrusted at 1790°C, and at 2200°C are eroded by slag.Translated from Ogneupory, No. 7, pp. 16–20, July, 1982.     

Preparation and investigation of the structure and properties of Al2O3 plasma-detonation coatings

Using a specially designed and constructed plasmatron, combining the plasma and detonation technologies, aluminum oxide coatings with high adhesion and strength (19.8 GPa) were obtained for the first time. The samples were studied by the transmission electron microscopy and X-ray diffraction methods and characterized for the first time by the Rutherford backscattering and proton elastic resonance measurements. It was found that the aluminum oxide coatings are composed of 0.20–0.25 μm crystallites, belonging to the α-, β-, γ-, and δ-Al₂O₃ crystal modifications, and have a transition region containing AlFe nanocrystals with a size of 20–40 nm and a considerable dislocation density. The aluminum oxide coatings exhibit significant carbonization, with a maximum carbon concentration on the surface reaching 20 at. %. The relative phase composition calculated using the X-ray diffraction data is as follows: γ-Al₂O₃, 60%; α-Al₂O₃, 30%; β-and δ-Al₂O₃, balance to 100%.     

Study of supramolecular assembly of porphyrins functionalized with cyano- and ester groups in coordination with transition metal salts and bidentate ligands

New peripherically functionalized porphyrins and their metallocomplexes are synthesized and studied using spectral analysis techniques (EAS, ¹H, ¹³C NMR) in the processes of supramolecular assembly with transition metal salts and exobidentate ligands. Formation of coordination porphyrin dimers is shown.     

Glutamate-induced cytotoxicity in PC12 pheochromocytoma cells: role of oxidation of phospholipids, glutathione and protein sulfhydryls revealed by bcl-2 transfection

Incubation of mock-transfected PC12 rat pheochromocytoma cells (PC12) for 2 h with increasing concentrations of glutamate caused progressive loss of viability (e.g., 67% with 15 mM glutamate). In contrast, the viability of bcl-2-transfected cells (PC12/bcl-2) was unaffected by glutamate. Neither PC12 nor PC12/bcl-2 cells showed a significant incidence of apoptosis in response to glutamate. Conventional phospholipid analysis by high-performance TLC and phosphorous determination showed no significant changes in the phospholipid composition of either cell line incubated with 5 mM glutamate. The peroxyl radical initiator 2,2'-azobis(2,4-dimethylvaleronitrile) caused a pronounced loss of all major phospholipid classes in PC12 cells, but no loss of cell viability. No phospholipid peroxidation was detected in PC12/bcl-2 cells incubated with 相似文献   

Physicochemical processes in modified fire- and thermal-protective two-layer filled epoxy polymers under the action of fire sources

A carbonized layer was formed by means of thermal treatment of the surfaces of glass- and organo-fiber plastics based on an epoxy binder premodified with flame-retardant phosphorus-containing compounds. To improve flame resistance of the carbonized layer, the active coats of swelling type which filled the cracks and pores were studied. The obtained data on the construction fire resistance confirmed the advantages of the two-layer fire and thermal protective coats over conventional ones.Izhevsk. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 2, pp. 73–79, March–April, 1995.     

Estimation of the Effect of Molybdenum on Chemical and Electrochemical Stability of Iron-Based Alloys

The E–pH diagram of Mo–H₂O system is refined. A cross-section of the Fe–Mo–O phase diagram at 25°C is constructed. The E–pH diagrams for the systems Fe–Mo–H₂O and alloy X17H13M2–H₂O are calculated. Thermodynamic aspect of the effect of molybdenum on chemical and electrochemical stability of iron alloys is discussed.