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The work assumed the possibility of the introduction natural fibers as a hybrid reinforcement of bio-polyethylene composites. Coconut fibers, basalt fibers and wood flour were used in different combination as a hybrid merger. Mechanical tests were conducted. An increase in the mechanical properties was shown as an effect of the introduction of the fibers info the polymeric matrix. A synergic influence of hybrid reinforcement was also presented. Experimental results were compared with modeling parameters. The hydrothermal and accelerated thermal ageing effects on the mechanical behavior of composites were presented. Scanning electron microscope images were observed in order to analyze structure of examined composites.

The paper describes the influence of the friction stir welding travel speed on the mechanical properties of the butt joints of copper plates. The results of static and fatigue tests of the base material (Cu-ETP R220) and welded specimens produced at various travel speeds were compared, considering a loading applied both parallel and perpendicularly to the rolling direction of the plates. The mechanical properties of the FSW joints were evaluated with respect to parameters of plates’ material in the delivery state and after recrystallisation annealing. The strength parameters of friction stir welding joints were compared with the data on tungsten inert gas welded joints of copper plates available in the literature. The results of microhardness tests and fractographic analysis of tested joints are also presented. Based on the above test results, it was shown that although in the whole range of considered traverse speeds (from 40 to 80 mm/min), comparable properties were obtained for FSW copper joints in terms of their visual and microstructural evaluation, their static and especially fatigue parameters were different, most apparent in the nine-fold greater observed average fatigue life. The fatigue tests turned out to be more sensitive criteria for evaluation of the FSW joints’ qualities.

The main objective of the article is to develop the concept of flock fragmentation and the averaging method for the application of electrocoagulation in the process of treating wastewater from coke ovens. The designed solution was part of an innovative system for the coke oven wastewater treatment process. The system is dedicated to removing the hazardous elements and compounds from wastewater from leaching ashes in municipal waste incineration plants. The design of the process and its automatization was based on a quantitative simulation method. The balance equations of mass, energy, and momentum of transport, complemented by the kinetics of the related reaction, are used during the calculation of the process. The main result achieved is a practical solution—the reactor’s scheme, classified due to a patent procedure in the Polish Patent Office.

Ever since its development in the 1990s, the friction stir welding method (FSW) has been increasingly popular in various industrial sectors, e.g. in transport, power engineering or electronic industry. In spite of its numerous advantages in comparison with conventional joining methods, the FSW method continues to be intensively investigates to develop appropriate technological parameters and geometry of tools ensuring the obtainment of joints characterised by excellent properties. The process of optimisation is required for each new material. The adjustment of proper FSW process parameters, particularly the tool rate of rotation and the travel rate, enables the obtainment of imperfection-free joints as well as significantly affects process efficiency decreasing its laboriousness and costs. The article addresses issues connected with the optimisation of the FSW process by analysing the effects of changes in the tool travel rate and the rate of rotation on structural and mechanical properties of aluminium joints. The tests involved the use of aluminium alloy grade 6063. The test joints were subjected to visual tests, hardness tests, microstructural examination, static tensile tests etc.

The thermal modelling of the Friction Stir Welding process allows for better recognition and understanding of phenomena occurring during the joining process of different materials. It is of particular importance considering the possibilities of process technology parameters, optimization and the mechanical properties of the joint. This work demonstrates the numerical modelling of temperature distribution accompanying the process of friction stir welding. The axisymmetric problem described by Fourier's type equation with internal heat source is considered. In order to solve the diffusive initial value problem a fully implicit scheme of the finite difference method is applied. The example under consideration deals with the friction stir welding of a plate (0.7 cm thick) made of Al 6082-T6 by use of a tool made of tungsten alloy, whereas the material subjected to welding was TiC powder. Obtained results confirm both quantitatively and qualitatively experimental observations that the superior temperature corresponds to the zone where the pin joints the shoulder.