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Ground (soil) heat flux is important physical factor primarily because of its role in surface energy balance, analysis of atmospheric boundary layer and land surface-atmosphere interaction. Direct measurement of this property is often associated with difficulties arising from need for adequate calibration of measuring devices, determination of proper depth for probes, upward water migration and accumulation below measuring plates to lack of understanding of the governing thermal processes occurring at the ground surface. In the following paper approach for inferring heat flux indirectly, from known ground surface temperature time-dependant functions, using previously developed fractional diffusion equation for ground heat conduction is elaborated. Fractional equation is solved for two, most frequently encountered harmonic surface temperature functions. Yielded results were compared with analytic solutions. Validation results indicate that solutions obtained with fractional approach closely correspond to analytic solutions with remark that former are more general, containing the term covering the transitional effect

In this paper we present achieved results of the Laboratory for Combustion of the Faculty of Occupational Safety in Nis Serbia, obtained by analyzing and designing of technologies and machines for manufacturing of briquettes and pellets by dry and wet process and identification of technological parameters of briquette manufacturing from waste biomass and coals like: humidity and granule, minimal formation pressure, adhesive type and minimal participation, as well as the possibility of designing biobriquettes with physical-chemical and energy properties given in advance. .

Self-shielded wire, tram-rail, block, fatique test REZIME:

The paper presents a proposal of mathematical models for the determination of propulsion coefficient, ηpp, intended for the analysis of motor freighters applied on the river watercourses. As the main paper contribution three different model types are developed, depending on the variable which contributes to ηpp value. These variables are: 1. the freighter sailing velocity, (v); 2. the installed capacity of the main drive motor of outboard unit, (Ninst); 3. the combination of these two variables, (N inst ,v). The models are verified on the examples of several motor freighters which are applied at Danube river. The special attention is paid to the determination of the optimum approximation function in each case. In all three cases it is a quadratic function. The correlation coefficient for the comparison in all analyzed examples is higher than 0.87, being even higher than 0.99 for the first model.