The empirical-analytic model of milling in a ring-ball mill has been presented. It concerns the interaction of the basic design features of the grinding unit (geometry, rate of grinding and thrust of the balls) on the maximum efficiency of the mill. The production of pulverized coal was expressed by the product of the flux of material drawn in by the balls and the so-called "grinding effect of the balls" (defined by the increase of the mass fraction of dust in its flux). The kinematic quantities (among others, the flux of loose material drawn in by the balls) have been calculated on the basis of a simple analytical description of the flow of particles and some parametrical assumptions. The grinding properties of coal have been determined making use of laboratory tests of its cruising by the rollers. Some verifications of the grinding model on the experimental test stand with a ring-ball mill have been presented. The test stand is installed at the Institute of Power Engineering and Turbomachinery of the Silesian University of Technology.

The software for co-ordinate measuring machine (CMM) is used for approximating geometric elements in plane (2d) and in space (3d) by approximation algorithms when number of measuring points obtained is larger than the minimum number of points necessary for element definition. Orthogonal regression methods are discussed in this paper. For 2d and 3d cases and they are compared with methods for defining straight line using linear regression. The advantage of orthogonal regression over linear regression is shown by comparing variance of measuring point displacement from both approximation line types.Algorithms for orthogonal regression make it possible to determine optimum position of a straight line for which value of variance of point distance from the line is the lowest possible. The tests have been performed on the Carl Zeiss CMM.

A DIRECT APPROACH to the problem of the separation of elastic strain energy in the case of generally anisotropic materials is described in the present work. It is based on a simple analysis of the strain tensor into a spherical and a deviatoric one. A definition of dilatational and distortional elastic strain densities is introduced, based on the consideration of the geometrical response of a material. Through the generalized Hooke's law, analytic expressions are obtained for the generally anisotropic materials. The present results coincide with the only available in the literature data for anisotropic materials with cubic symmetry. In addition, an application for transversally isotropic materials is presented.

This study presents general properties of dough as demonstrated within the period of its technological usefulness (i.e, approx. up to 30 min). Eight (8) types of dough made of four (4) types of flour were subjected to experimental tests. During examination of dough, treated as a non-Newtonian fluid, its non-Newtonian (apparent) viscosity was determined as well as its correlations with other rheological quantities. The results of the study were shown in diagrams presenting the course of particular quantities and model correlations of examined types of dough. These relations were used to determine one general expression modeling rheological properties of examined doughs.

The paper presents methods of analytical and measurement-based determination of pressures acting on sheet metal in the process of electrodynamic forming by means of flat inductors generating pulse magnetic field. Pressures are determined for sheet metal of different thicknesses processed by means of circular and elliptical spiral inductors. The paper describes also examples of copper and aluminium sheet metal forming conducted by means of the analysed inductors and shaped forming dies.

The study of the geometry for worm-gearing is much more complicated than that of plane gearing, since worm-gearing is three-dimensional. A numerical method to determine the conjugate profile of worm-gearing tooth is developed. The software, with numerical set-up and graphic display, is an original and special program, and it could be adopted for the geometry of any kind of cylindrical worm-gearings, as well as for spur gearings and bevel gearings.

The paper there presents the analysis of low-cycle fatigue test results of 30 HGSA alloy steel obtained with the use of two methods. In the standard method, fatigue tests were performed with the use of many specimens, and in the simplified method, the results were defined in an incremental step test using one specimen. Test results were analysed taking into account the influence of loading form on the course of a stabilization process with defined material data. The analysis of the stabilization process in diversified conditions of loading was performed by comparison of the stress amplitude CTa and strain amplitude Eap for the same levels of total strain amplitude Eac• Basing on the tests, one could state that both methods of defining the cyclic properties lead to qualitatively and quantitatively convergent results. The results exhibit qualitative similarity as far as the character of courses of changes determined in different periods of life of n' and K' parameters of the cyclic strain chart is concerned, and quantitative similarity of the values of determined parameters.