Leachate water from sanitary landfills represents one of the most complex global environmental problems. This paper examines the possibility of using aluminosilicate material, pyrophyllite, from the Parsovići deposit, as an adsorbent. It was researched the influence of two granulations of pyrophyllite (0-53 μm and 0-100 μm) on the degree of adsorption of heavy metals (Fe, Ni, Mn) from leachate water from the municipal landfill "Desetine", Tuzla. The adsorption experiment was performed using the Batch method, depending on the contact time between the adsorbent and the adsorbate, the mixing speed, and the mass of the adsorbent, pyrophyllite, through two treatments. The results indicate a higher efficiency of the finer fraction of pyrophyllite, and in the competition of the three examined metals, iron is completely removed in the first treatment with both granulations and then nickel with finer granulation and manganese with coarser. After the first treatment, the unpleasant smell was removed, which is certainly a consequence of the removal of ammonia compounds as the most abundant compounds in leachate water. In these pioneering researches, pyrophyllite proved to be effective, and at the same time, it is a cheap, easily available, and environmentally friendly material for leachate water purification.

The micro-roughness represents the basic structure of the roughness of the treated surfaces and they are mainly a consequence of the machining during the production. The microgeometry of treated surfaces has a significant impact on the contact conditions of surfaces, which is reflected in the quality of gluing, pressing, and surface treatment and assembly, ie the interchangeability of structural details of the product, and thus the product quality. The roughness of treated wood surfaces is almost impossible to reliably determine theoretically using analytical models, and the application of experimental analysis of the investigated influential parameters is essential to improve the treatment regime, while maintaining the cost and quality of treatment at a satisfactory level. The aim of this paper is to examine the significance of the influential parameters of roughness of the treated surface, ie wood density, feed rate and cutting depth when turning solid wood elements, and analysis of experimental data for achieving lower roughness of the treated surface, without compromising the quality and total production costs. The purpose of the experimental plan is to generate a mathematical model that describes the process.

This study aims to investigate the influence of thermal modification (TM) on the physical and mechanical properties of wood. For this purpose, the experimental part focused on selected influential parameters, namely temperature, residence time, and density, while the four-point bending strength is obtained as the output parameter. The obtained experimental data are stochastically modeled and compared with the model created by genetic programming (GP). The classical mathematical analysis obtained treatment parameters in relation to the maximum bending strength (T = 187 °C, t = 125 min = 0.780 g/cm3) and compared with the results obtained by genetic algorithm (GA) (T = 208 °C, t = 122 min, and = 0.728 g/cm3). It is possible to obtain models that describe experimental results well with stochastic modeling and evolutionary algorithms.

The paper presents the results of modeling the bending strength of wood. During the experimental examination and definition of the model, solid wood was taken, where the bending was performed perpendicular to the grain. The experiment was done with thirteen replications and the input values that varied at three levels were wood density and board thickness. The thirteen-repetition experiment also involved four repetitions in the marginal areas, so two more wood densities and two board thicknesses had to be taken. The experimental measurement was performed in the laboratory of the Technical Faculty Bihać. Based on the experimental results, a sufficiently adequate mathematical model of the breaking force of a solid wood panel perpendicular to the grain is obtained.

Paper presents the design of experiment and determining mathematical model to calculate roughness parameter of wood planned surface. For design of experiment three different types of solid wood were taken and processed on the planner with three different displacements and three different cutting speeds. After measuring the roughness parameter Rz, experimental results were obtained on the basis of which the central composite plan of the experiment was made. Based on that, a model of roughness parameter Rz was made, which is adequate and with high accuracy. The significance of the model coefficients was determined using the R software and the results were presented using the Design Expert software.