Optimizing the tapping regime on a blast furnace operating at variable speed

The main factors that determine the uniformity with which smelting products are tapped from a blast furnace are the rate of accumulation of the products in the hearth and the tapping rate. The first parameter is in turn determined by the stability of the furnace’s operation and can vary significantly even over the course of 24 h. The second parameter is determined mainly by the condition of the iron notch, the maintenance it receives, any changes that occur in the diameter of the channel of the notch, and the quality of the materials used to form the notch. Recommendations are presented to optimize tapping of the smelting products.     

The treatment of peripapillary diverticula of the duodenum

An original operation is proposed for localization of the diverticulum in the descending portion of the duodenum which excludes traumas of the pancreas. Clinical observations are described.     

Effect of chromium and binder on diamond-matrix contact strength

The vacuum production of diamond drill bits is considered. The effect from the concentration of an adhesive-active element (chromium) on the diamond-tool contact strength is analyzed. It is examined how the binder affects the dependence of diamond-retaining force on the chromium content.     

Periclase —spinel products from magnesite powder with high alumina content

Conclusions Periclase-spinel articles with low contents of chromite made from magnesite powder containing magnesia-alumina spinel have a high range of physicochemical properties (except spalling resistance) and completely satisfy the requirements in service for the roofs of open-hearth and walls of electric steel-melting furnaces.With an increase in the content of magnesite in the fine constituent, it is possible to obtain products of the same quality from magnesite powder with a high porosity (up to 20–23%).The change in ratio of chrome spinel and magnesia-aluminous spinel in the periclase-spinel articles toward a certain increase in the latter is worthy of attention and requires further investigation.Translated from Ogneupory, No. 2, pp. 11–15, February, 1966.     

Choice of method for the determination of the strength of diamond fastening in the drilling tool matrix

We discuss the main methods of modeling and assessment of the strength of diamond fastening in the tool. It is shown that the diamond-holding components comprise mechanical fixing and adhesion to the matrix. A method for the determination of the adhesion component of diamond holding is proposed, and results obtained as a function of the adhesion-active element content of the tool matrix are presented. __________ Translated from Problemy Prochnosti, No. 6, pp. 144–151, November–December, 2007.     

The aquathermolysis of heavy oil from Riphean-Vendian complex with iron-based catalyst: FT-IR spectroscopy data

In this paper, we investigated the influence of steam treatment on structural group composition of resins and asphaltenes of heavy oil. The object of investigation was oil-saturated rocks from Riphean-Vendian complex. The extracted crude oil was determined as a high-viscous fluid. The resins and asphaltenes destructed in a small extent due to thermal treatment. The oil-soluble iron-based catalyst intensified the destructive processes. The content of sulfur compounds (-SO) in resins and asphaltenes drastically decreased due to reduction reaction of sulfoxide to sulfide and hydrogen sulfide. The results showed that catalytic aquathermolysis, even at low temperature ranges, promoted the cracking reaction of most macromolecular components and increased the content of light fractions of heavy oil. Consequently, it reduced its viscosity.     

Diamond-hard alloy macrocomposite material: Development and application

A new diamond-hard alloy macrocomposite material consisting of diamond grits (0.5–0.8 mm or more in size) and a WC-Co matrix has been developed. The material is characterized by high mechanical properties of the matrix (the same as for WC-Co monolithic hard alloys) while diamonds remain completely intact (no graphitization or dissolution in cobalt melt). This process does not require superhigh pressures. Hard-alloy samples sintered beforehand in conditions that ensure the maximum mechanical properties (1450–1500°C, 30–60 min holding) are used as initial materials. Hollows (cells) or ditches of specific sizes (depth, width) are made in these samples with mechanical or electrophysical methods, and then diamond crystals (grits) commensurate with the hollows, cells, or ditches are placed in them. Vacuum infiltration (brazing) at moderate temperatures (900–1150°C) with adhesion-active alloys (or metallized diamonds) is the final stage in the formation of the composite. Therefore, strong adhesion-mechanical fixation of diamond grits in the hard-alloy matrix is ensured. The new material is efficiently used in diamond bits.     

Effects of resistive switching in Au/FeO<Subscript>x</Subscript>/Pt structures

The dynamics of forming and resistive switching in Au/iron oxide/Pt structures based on magnetite (Fe₃O₄) is investigated. It has been revealed that these processes have an electrochemical nature and are accompanied by formation of low-resistance conductive filaments formed by inclusions of magnetite in the matrix of high-resistance maghemite (γ-Fe₂O₃). It has been found that the electric field stimulates reversible redox reactions in iron oxide. The direction and rate of these reactions are determined by the polarity and the amplitude of voltage pulses. The possibility of setting the resistance of the structure by changing the amplitude of the “record” voltage pulses opens prospects for the development of multilevel memory elements.