Effect of different factors on the quality of raw pellets

Belgorod Branch of the Mekhanobchermet Institute. Lebedin Mining-Concentration Combine. Translated from Metallurg, No. 2, pp. 28–29, February, 1989.     

CABARET scheme’s modification ensuring its high accuracy on local extrema

It is demonstrated that the standard flow-variables’ correction required for the monotonicity of the CABARET scheme reduces its accuracy near local extrema. A modified correction of the flows is proposed; it retains the strong monotonicity of the CABARET scheme for Courant numbers r ∈ (0,0.5], and thus ensures its high accuracy near local extrema. The results of the test computations of discontinuous solutions of a nonlinear transport equation are presented; these results illustrate the advantages of the modified scheme.     

On the application of thermoluminescence for probing the energetic disorder in amorphous molecular solids

The low-temperature thermoluminescence (TL) technique has been applied for probing the energetic disorder in doped poly(N-epoxypropylcarbazole)(PEPC) polymer films. Strong polar dopants were used for varying the degree of dipolar disorder. It was found that (1) the TL of the studied systems can be well interpreted in terms of the disorder model and (2) TL spectroscopy can provide the shape of the deepest part of the localised state distribution and the degree of energetic disorder as well. The charge trap distribution on the high-temperature side of the TL peak appears to be a Gaussian function and its halfwidth correlates well with the disorder parameter obtained from charge transport measurements. An unusual electric field effect on the TL of PEPC doped with strong polar dopants was found and is explained in terms of the contribution of the charge-dipole interaction to the energy of localised states. This effect indicates that the TL phenomenon for the studied systems cannot be explained purely by molecular γ-relaxation in the polymer. © 1997 John Wiley & Sons, Ltd.     

Structure and properties of electric-spark alloyed TiN,TiB<Subscript>2</Subscript>, and Mo coatings on VT22 titanium alloy and their transformation under light-thermal treatment

We have established that electric-spark alloyed TiN, TiB₂, and Mo coatings improve substantially the tribotechnical characteristics of VT22 titanium alloy. It has been shown that an increase in the slip velocity from 1.0 to 10 m/sec increases the wear intensity and friction coefficient by a factor of 1.5–2 and 1.3, respectively. A significant amount of oxides in the coatings and their additional alloying with titanium after treatment by concentrated solar radiation favor a 3–4 times increase in the layer thickness but lower its tribotechnical properties.     

Friction behaviour and wear resistance of diamond-like carbon films under cryogenic temperatures

A study has been made of the friction behaviour and wear resistance in liquid nitrogen medium of pin-and-disc pairs with diamond-like carbon (DLC) coatings deposited onto disc surfaces of varying initial roughness, and in a number of cases onto pin surfaces. The dependence of the coefficient of friction on initial roughness has been shown to be extreme. Peculiarities of microrelief formation at the contact surface and the composition of the wear debris for the DLC-coated mating pairs were observed. Possible mechanisms of friction interaction for diamond-like coatings at cryogenic temperatures are considered.     

On monotonicity of two-layer in time cabaret scheme

The paper analyzes the monotonicity of the two-layer in time cabaret scheme. It is shown that there is no local one-time correction of flow variables which would provide monotonicity for this scheme at any monotonic initial data. A modification of the two-layer in time version of the cabaret scheme is suggested that is a double correction of flow variables, which, in the case of a variable time step, provides this scheme with monotonicity at any Courant numbers. The results of test calculations illustrating the advantages of the modified scheme are given.     

Reagent treatments of sediments built up in sedimentation tanks of the Dnieper river water station

Laboratory experiments, modeling compaction of sediments building up in sedimentation tanks of water stations under the influence of a GKZh-11 hydrophobizing liquid, the solution of polyhexamethylene guanidine (Aquaton), aluminum sulfate, were carried out. We have determined optimal doses of reagents. It has been shown that the greatest effect of compacting of sediments (21–23%) is achieved by the use of a GKZh-11 hydrophobizing agent and also with a joint action of the hydrophobizing agent and aluminum sulfate (13–18%). The obtained data present a practical interest when developing the technology of treating sediments of washing waters of the sedimentation tanks and filters of water-treatment facilities.     

Structure and Properties of Ceramics Based on Monetite and Nanodispersed Silica

Powder Metallurgy and Metal Ceramics - Calcium–phosphate ceramics based on monetite and nanosized silica are produced by sintering at 500°C. It is established that phase changes and...     

The method of elimination of unknowns for systems of linear inequalities with graph structure

The method of elimination of unknowns in a system of linear inequalities is considered. This method is used to solve systems of linear inequalities whose structure is defined by some graph. The concepts of terminal and intermediate graphs are introduced. A new system of inequalities derived by eliminating a group of unknowns that correspond to these subgraphs is described. Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 66–74, September–October, 1999.