Unit for the cassette-less pulsation washing of the channels of housing parts

Chemical and Petroleum Engineering -     

The Application of Fibers and Nanoparticles in the Form of Copper-Based Powder Sintered Friction Material with Lubricant Cooling

The modern development of automotive engineering and special-purpose machines has led to the need to increase the energy loading of friction units and provide smooth switching on and pulling away, as well as to prolong the service lives of vehicles. Domestic experience in using hydromechanical gear-boxes and oil-cooling brakes indicates that sintered friction powdered MK-5 material, a sintered blend of tin bronze reinforced with graphite particles, has become the most widespread material for this purpose. In the present work, various fibers of glass, basalt and carbon have been successfully applied as friction-purpose fillers for enhancing the tribotechnical characteristics of the material. The effect of nanoparticles as filler of sintered friction material has also been studied. In particular, embedding aluminum hydroxide (bumite) nanoparticles increases the coefficient of friction, while intermetallides (aluminides of nickel, iron and titanium) decrease the wear rate.     

Deformation of Rodlike Elements of Composite Materials Subjected to Uniform Compression

On the basis of generalization of the results of investigation of the operation of rodlike elements of composite materials, we make a conclusion that the influence of various factors on the deformability of these elements is studied incompletely. The comparison of the stress-strain states for different models of concrete and reinforced-concrete elements makes it possible to describe the effect of longitudinal reinforcement (coefficient of reinforcement, strength and deformation characteristics) on the critical level of strains in the cross section. According to the results of our investigations, we give recommendations concerning the evaluation of the critical value of the coefficient of reinforcement above which one may observe the effect of reinforcement on the deformability of the analyzed sections. It is shown that the compression strength of the brittle base of the composite with inhomogeneous structure decreases as a result of the fracture processes. It is also demonstrated that the existing procedure used for the evaluation of the indicated decrease in strength requires significant improvement. The problem of evaluation of the ultimate value of the coefficient of reinforcement is also analyzed.     

Calculation of Some Properties of the Cubic Oxides of II-VIII Group Metals

Experimental data on the bulk modulus of elasticity, thermal expansion coefficient, specific heat capacity, specific volume, Grueneisen constant, and atomization energy of the cubic monoxides of Mg, Ca, Sr, Cd, Ba, Eu, Th, U, Pu, Ti, Zr, V, Nb, Ta, Cr, Mn, Fe, Co, and Ni were analyzed. Using six correlation relationships values of unknown properties and adjusted values of known properties at 298 K were calculated.

     

Lattice potential energy and equation of state of chromium and its compounds

The bulk moduli are calculated for compounds of chromium with light elements (B, C, N, O, Si) and the Buckingham potential parameters m and n are determined. The relations are found between m and the heat capacity, thermal expansion coefficient, and energy of atomization and between n and the Grüneisen constant are determined. The U(V) and P(V) diagrams are calculated and the characteristics of the interatomic bond strengths at the hypothetical negative pressure of uniform tension are determined.Institute of Problems in Material Sciences, National Academy of Sciences of Ukraine, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 1/2(377), pp. 40–47, January–February, 1995.     

Interatomic reaction potentials in titanium diboride

Characteristic temperatures determined by Ti−Ti, Ti−B, and B−B bonds in TiB ₂ are evaluated. Values for the heat capacity, thermal expansion coefficient, bulk elasticity modulus, Grüneisen coefficient, and also exponents for Mie—Grüneisen, Morse, and Buckingham type potentials, and the critical pressure and volume of PV-diagrams are calculated for these bonds. The corresponding properties of these bonds and boride are noted. Indices of the Buckingham potential point to the preferred covalent nature of Ti−Ti, Ti−B, and B−B bonds in titanium diboride. Institute for Problems of Materials Science, Ukraine National Academy of Sciences, Kiev. Translated from Poroshkovaya Metallurgiya, Nos. 5–6(407), pp. 97–101, May–June, 1999.     

Electric drives of mine-lifting machines

The problems of the development and industrial application of electric drives for mine-lifting machines are discussed. Two types of electric drives, i.e., AC electric drives with a cycloconverter-fed synchronous motor and DC drives, are described.