This paper deals with computer modelling of the retention of a synthetic diamond particle in a metallic matrix produced by powder
metallurgy. The analyzed sintered powders can be used as matrices for diamond impregnated tools. First, the behaviour of sintered cobalt
powder was analyzed. The model of a diamond particle embedded in a metallic matrix was created using Abaqus software. The
preliminary analysis was performed to determine the mechanical parameters that are independent of the shape of the crystal. The
calculation results were compared with the experimental data. Next, sintered specimens obtained from two commercially available powder
mixtures were studied. The aim of the investigations was to determine the influence of the mechanical and thermal parameters of the
matrix materials on their retentive properties. The analysis indicated the mechanical parameters that are responsible for the retention of
diamond particles in a matrix. These mechanical variables have been: the elastic energy of particle, the elastic energy of matrix and the
radius of plastic zone around particle.
Hydrological modelling uses modern computational methods to simulate local and regional water circulation systems. How does this work, and what benefits does it bring?
In 2015 an important part of the official evaluation of Polish scientific journals was left to experts’ judgement. In this paper we try to establish which observable factors (with available data) are closely related to the outcome of experts’ evaluation of Polish journals in economic sciences. Using the multiple regression statistical model we show that only 5 variables (out of 17) significantly explain almost 50% of the empirical variance of the experts’ evaluation. The determinants of particular interest, not entering the formal criteria and not related to the impact on global science, are: the number of citations mainly in Polish journals and the affiliation with the Polish Academy of Sciences.
The article concerns computer modelling of processes in cooling systems of internal combustion engines. Modelling objectives and existing commercial programs are presented. It also describes Author’s own method of binding graphs used to describe phenomena in the cooling system of a spark ignition engine. The own model has been verified by tests on the engine dynamometer. An example of using a commercial program for experimental modelling of an installation containing a heat accumulator is presented.
Prof. Daniel Wójcik from the Nencki Institute of Experimental Biology explains the principles of brain modelling
This paper introduces security assessment methodology for isolated single-workstation multilayer systems processing sensitive or classified data according with a corresponding security model for such system. The document provides a high-level tool for systematizing certain-class-systems security models development. The models based on the introduced methodology cover data confidentiality and availability attributes protection on a sufficient level.