Application of magnesia concrete and brick for the lining of electric furnaces

Conclusions Self-setting magnesia concrete and solutions are applicable for the lining of electric furnaces in the form of blocks.The testing of magnesia concrete and basic brick blocks is recommended on an industrial level for the verification of their effectiveness in electric furnaces of different capacity.     

A rammed lining for ladles for teeming of manganese alloys

Refractories and Industrial Ceramics -     

Statistical analysis of the scale factor in the strength of high-modulus fibres

Conclusions Distribution curves for the probability density of the strength values of complex SVM and Terlon yarns have been investigated with variation in the clamped length of specimens from 5 to 500 mm.The best conformity between the empirical distribution of yarn strength figures was observed for a distribution law for extreme values of the third kind, which conforms to the weak-unit theory.With increase in clamped length, disappearance of both very large and also of very small values of yarn strength takes place and because of this a shift in the modal value of strength takes place in the direction of low values. The latter circumstance is explained by the special features in the technology of making ultrahigh-modulus yarns.VNIIPV, Kiev Branch. Translated from Khimicheskie Volokna, No. 2, pp. 32–34, March–April, 1992.     

The best shape and size for the reel of thread on a spinning machine

Conclusions 1. The labour requirements of the production of thick cord threads might be reduced by increasing the winding time of the reels of thread on the machines, i.e., by increasing the dimensions and weights of the reels.2. It has been found possible to obtain good-quality reels with square ends: the amount of thread wound on an ordinary bobbin can thus be considerably increased.3. To obtain reels of increased diameter with square ends, it is necessary to increase the angle of pitch of the windings, which in turn means roughly doubling the speed of reciprocation of the thread guide of the distributing mechanism.4. If the fineness of the formed thread is reduced below 187 tex (N 5.35), it is advisable to go over to other methods of taking up the thread in the spinning machines, e.g., into containers.VNIIMSV, Chernigov. Translated from Khimicheskie Volokna, No. 2, pp. 53–55, March–April, 1969.     

Numerical simulation of electrode process in Cu/CuSO4 + H2SO4 system

In the present work, electrode process in the system Cu/CuSO₄+H₂SO₄ is considered as a sum of two single-electron electrochemical reactions that occur simultaneously on copper electrode. Numerical modelling of this process was performed taking into account diffusion, electromigration, and chemical interactions between the components of the solution. The results of calculations do not contradict the experimental facts known for this system. The behaviour in the region close to the open circuit potential can be explained by the differences in the partial currents of the reactions proceeding on the electrode. The behaviour of the surface concentrations of the components of solution in the region of the anodic overpotential points to a substantial role of electromigration processes that can be played by them in copper passivation in sulphate solutions.     

Guniting the lining of heating furnaces of rolling mills

Conclusions Guniting mass compositions and a procedure for guniting worn brickwork of continuous heating furnaces of rolling mills have been developed. At a number of metallurgical factories the worn brickwork of eight continuous heating furnaces of rolling mills have been repaired by guniting. The use of guniting enables the period between furnace lining repairs to be doubled (from 1 to 2 years), the volume of brickwork repair and the length of the repair work to be reduced, and a saving of 5000 rubles per annum per furnace to be obtained (merely by reducing the amount of repair work).Using IR spectroscopy the authors have investigated hydration and dehydration in alumina and high-alumina cements and aluminosilicate guniting masses with additives of these cements. They have shown that during guniting by the semidry method, hydration of the cements included in the composition of the gunite coatings does not go to completion and ends in the stage of formation of CaO·Al₂O₃·10H₂O; dehydration of the gunite coatings is completed below 300°C.Translated from Ogneupory, No. 5, pp. 30–35, May, 1980.     

On the mechanism of weakening and breaking of gas detonation in channels with acoustically absorbing walls

The physical mechanisms of the weakening of detonation waves in channels with acoustically absorbing and, particularly, porous walls are analyzed on the basis of experimental data available. The effect of weakening (and breaking) of a multifront detonation wave due to the inelastic properties of the channel walls was numerically investigated within the framework of a simplified mathematical model for propagation of two-dimensional gas detonation. The role of different physical mechanisms in the narrowing of the domain of near-critical detonation regimes observed experimentally is determined. A criterion for effectiveness of the influence of the acoustic properties of the wall on the detonation wave is formulated.Institute of Thermophysics, Novosibirsk 630090. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 4, pp. 71–76, July–August, 1995.     

Apparatus for determining the strength of the adhesion of the Gunite coating to the refractory masonry in breakaway tests

Conclusions Apparatus was designed and constructed for determining the strength of the adhesion of Gunite compositions to refractory masonry. It was shown that the strength of adhesion of the Gunite compositions developed for guniting the roof of open-hearth furnaces during the smelting cycle is adequate.Translated from Ogneupory, No. 1, pp. 58–60, January, 1977.     

Strength level of high-strength complex fibre from stiff-chain polymers

The discrete strength levels for ultrahigh-modulus Terlon, Armos, and SVM fibre were found. Small-angle x-ray scattering and the calculation procedure known as the method of tangents were used to estimate the radii of submicrocracks. The limiting and actual values of the average strength levels of these types of fibre were calculated for two characteristic radii of inertia R₁ and R₂. The agreement of the results with the published data confirms the accuracy of the method of tangents.Ukrainian Scientific-Research Institute of Fibre, Kiev. Translated from Khimicheskie Volokna, No. 6, pp. 33–35, November–December, 1992.