In the recent time forest harvesting is mainly related to the use of chainsaws. They are acceptably light, safe, cheap and multifunctional. At the same time, chainsaws can cause personal illnesses considering their vibrations and noise. This article deals with conditions and assessment evaluation of effects on workers caused by vibrations and noise in the case of professional chainsaws in operation. Mechanical vibrations and noise are mainly related to the back-and-forth movement of the piston, and to a lesser extent, to the cutting chain. The experiment revealed, in general, that design parameters have a minimal influence on chainsaw vibration and noise emissions. Specifically, the statistical analysis for frequency weighted vibration showed no difference between types of guide bars, types of saw chains and wood plant in terms of noise and vibration on handles.

Porous materials bring components not only direct advantages in the form of lightening of constructions, saving of production materials, or improvement of physical properties, but also secondary advantages, which are manifested as a result of their daily use, e.g., in aviation and the automotive industry, which is manifested in saving fuel and, thus, environmental protection. The aim of this article is to examine the influence of the volume ratio of a complex porous structure, the so-called Neovius, on bending properties. Samples with five different relative weights of 15, 20, 25, 30, and 50% (±1%) were fabricated from AlSi10Mg aluminum alloy by Direct Laser Metal Sintering (DLMS) technology. A three-point bending test until specimen failure was performed at ambient temperature on a Zwick/Roell 1456 universal testing machine. The dependences of the bending forces on the deflection were recorded. The maximum stresses, energy absorption, and ductility indexes were calculated to compare the bending behavior of beams filled with this type of complex cellular structure. The results showed that Neovius, with a relative weight of 50%, was much more brittle compared to the other samples, while the Neovius structure, with a relative weight of 30%, appeared to be the most suitable structure for bent components among those tested. This study is a contribution not only to the development of the space and aviation industry but also to the expansion of the knowledge base in the field of material sciences. This know-how can also provide a basis for defining boundary conditions in the simulation of behavior and numerical analyses of 3D-printed lightweight components.

The paper describes the surface roughness measurement of functional parts of tools for minting coins. The coining dies were coated with three types of coatings - CrN, TiCrN and WC/C. Roughness of the coining die surface is a very important fac...

The proportion of cableway skidding is still increasing compared to other technological and transportation ground-based ways of wood skidding which can dramatically change the quality of the environment. Wood skidding can be performed by an unconventional double-drum tractor winch powered by the wheels of the tractor rear axle. The principle of this unique tree transportation cable system with working attachment is protected by the patent. The article is focused on the description of working functions of this transportation system and the analysis of the dynamic strain of the forestry cableway system at different stages of its operating cycle. During the experiment the forces in the towing rope at different weights of tree logs and different speeds of their towing were measured and evaluated.

The article is focused on the use of Quality Management tools to identify causes of formation deviations dimensions in cylinder head castings. Moreover, methods of production of castings made from alloy AlSi9Cu1, heat treatment of castings, as well as requirements of their quality are described. Research of the influence heat treatment parameters on the changes of castings' dimensions, with using Quality Management tools (Ishikawa diagram) is described too. In order to optimize the process for eliminate of deviations, experiment for modelling parameters of heat treatment was designed. The results processed in the Pareto diagram clearly pointed out the causes. Dimensional deviations were created during the heat treatment process. We have found the largest distortions in castings were created during rapid cooling. The article gives important information about using of research results in the production of cylinder head castings.