Effects from major horizontal-quenching parameters on product quality

Translated from Steklo i Keramika, No. 11, pp. 10–12, November, 1989.     

A circular tunnel kiln for firing of refractories

Conclusions The first high-temperature circular tunnel kiln in the country, in which firing of mullite-corundum refractories with a phosphate binder at 1400–1500°C has been introduced, has been placed in service.The operation of the kiln is characterized by the high service reliability of its design elements, including the hearth system, and insignificant costs for routine repairs of the kiln equipment.Translated from Ogneupory, No. 2, pp. 40–44, February, 1985.     

Modeling of nucleation of orthosilicic acid in geothermal brine

On the basis of a mathematical model, a program is developed for numerical modeling of orthosilicic acid nucleation in geothermal brine with the formation of colloidal silica particles. Data on the dependence of the process parameters on the properties of brine (temperature, pH, and total silica concentration) are obtained. These data can be used to design technological systems of silica removal from the geothermal heat-transfer medium.     

Use of X-Ray Thickness Gauges in Manufacturing Rolled Non-Ferrous Metals

A technique of taking into account modifications of the chemical composition of alloys in measuring the thickness of rolled non-ferrous metal products by X-ray thickness gauges is described. The possibilities and perspectives of using RIT10 X-ray thickness gauges in rolling mills with a wide assortment of treated non-ferrous metals and their alloys are demonstrated. The accuracy reached in measurements of tested objects of different thicknesses and chemical compositions is estimated and factors affecting the accuracy of device readings are indicated.     

The role of cytoplasmic [Ca2+] in glucose-induced inhibition of respiration and oxidative phosphorylation in Ehrlich ascites tumour cells: a novel mechanism of the Crabtree effect

The effect of Ca2+ on energy-coupling parameters of Ehrlich ascites carcinoma was studied in digitonin-permeabilized cells. In nominally Ca-free medium the permeabilized cells respond to the addition of ADP by increased oxygen uptake with externally added respiratory substrates (succinate or pyruvate), decrease of the mitochondrial membrane potential (delta psi) and alkalinization of the medium. This typical behaviour is drastically changed if Ca2+ is added. The subsequent addition of ADP induces neither State 3 respiration, nor decrease of delta psi, nor alkalinization of the medium, indicating a complete block of ATP synthesis. These effects are produced by both a single pulse of 100 microM Ca2+ and a preincubation for 2 min with 0.4-1.0 microM Ca2+. Preincubation of the cells with glucose or deoxyglucose prior to permeabilization makes them sensitive to Ca2+ concentrations as low as 0.3 microM. In view of the previous finding that glucose and deoxyglucose produce an increase of cytoplasmic [Ca2+] in Ehrlich ascites cells [Teplova VV. Bogucka K. Czyz A. Evtodienko YuV. Duszyński J. Wojtczak L. (1993) Biochem. Biophys. Res. Commun., 196, 1148-1154; Czyz A. Teplova VV. Sabala P. Czarny M. Evtodienko YuV. Wojtczak L. (1993) Acta Biochim. Polon., 40, 539-544], the present results suggest that cytoplasmic Ca2+ plays a crucial role in the Crabtree effect.     

The P300 component of the auditory evoked potential in the posttraumatic vegetative state

The dynamic studies of P300 component of the acoustic evoked potential were conducted in 12 patients in posttraumatic state of the autonomic system. The amplitude and time parameters of P300 were analyzed, its spatial distribution over the cortex, and features of generation. The obtained results were compared with the normative data. Significant changes in P300 in comparison with the normal characteristics were revealed in patients with the absence of conscious mental activity. These changes were maximally expressed when the state of patients was irreversible. In case of patients' outcome from the studied state the amplitude-temporal and topographic response characteristics tended to normalization but did not reach it completely. The obtained results allow us to consider the P300 component as one of the most informative indices in consciousness recovery after severe brain injury.     

Physicochemical Processes during Precipitation of Silica from Geothermal Brine

Physicochemical properties of the silica–geothermal brine colloidal system are investigated. The reaction order and the rate constants for silica polymerization are determined, the radius of colloidal particles is measured, and their charge is estimated. The mechanism of coagulation and precipitation of colloidal silica by metal cations is experimentally studied. On the basis of the results obtained, a basic process to recover silica from the geothermal heat-transfer medium is designed.