In this paper, a mathematical model for projectiles shooting in any direction based on sensors distributed stereoscopically is put forward. It is based on the characteristics of a shock wave around a supersonic projectile and acoustical localization. Wave equations for an acoustic monopole point source of a directed effect used for physical interpretation of pressure as an acoustic phenomenon. Simulation and measurements of novel versatile mechanical and acoustical damping system (silencer), which has both a muzzle break and silencer properties studied in this paper. The use of the proposed damping system can have great influence on the acoustic pressure field intensity from the shooter. A silencer regarded as an acoustic transducer and multi-holes waveguide with a chamber. Wave equations for an acoustic monopole point source of a directed effect used for the physical interpretation of pressure as an acoustic phenomenon. The numerical simulation results of the silencer with different configurations presented allow trends to be established. A measurement chain was used to compare the simulation results with the experimental ones. The modeling and experimental results showed an increase in silencer chamber volume results in a reduction of recorded pressure within the silencer chamber.

The aim of the study was to determine and analyse the costs of harvesting and storage of maize straw for biogas production. The investigations showed that it was the most economical to harvest maize straw with a self-loading wagon equipped with a cutting system and to store it in a field prism. The cost of this technology amounts to €12.5 per Mg d.m. The cost of maize straw harvest with a field chopper and storage in a flexible silo was the highest, amounts to €126.9 per Mg d.m. The research findings can be used for estimating the profitability of harvesting maize straw for energy production and other industrial purposes.

The paper presents the results of research aimed at the verification of the existing design solutions of four example sowing units for agricultural seed drills with the most frequently used types of sowing wheels. The research was conducted with the use of modern computer simulation systems based on the discrete element method (DEM) with the evaluation of the efficiency of selected design solutions in terms of achieved performance and metering uniformity. The paper includes a description of virtual research models and the employed mathematical models used for mirroring contact between seeds. Moreover, for the purpose of verification of the obtained results, bench tests were conducted using actual models of selected design solutions.

Crude oil prices have a key meaning for the economies of most countries. Their levels shape the general production costs in many sectors. Oil prices are also a base for financial derivatives like CFD contracts, which are popular nowadays. Due to these reasons, the possibility of an effective prediction of the direction of future changes in the price of crude oil is especially significant. Most existing works focus on the analysis of daily closing prices. This kind of approach results, on the one hand, in losing important information about the dynamics of changes during the day. On the other hand, it does not allow for the modelling of short-term price changes that are especially important in cases of financial derivatives having crude oil as their base instrument. The goal of the following article is the analysis of possible applications of a binary–temporal representation in the modelling and construction of effective decision support systems on the crude oil market. The analysis encompasses all researched state models, e.g., those applying mean and trend analysis. Also, the selection of parameters was optimized for Brent crude oil rates. The presented research confirms the high effectiveness of our state modelling system in predicting oil prices on a level that allows for the construction of financially effective investment decision support systems. The obtained results were verified based on proper backtests from different quotation periods. The presented results can be used both in scientific analyses and in the construction of investment support tools for the crude oil market.

The main purpose of the performed works was to develop a concept of a bulldozer blade mounted to the road roller. The paper presents the main assumptions, design stages, results of strength analyses of the blade, which can be used in a road roller. Because the elements that push the components of machines operating on construction sites, in mines and in the agricultural environment, the elaborated element would enable wider use of the roller. Based on the FEM analyses, it has been confirmed that the developed load bearing structure is characterized by full operating strength. The designed blade meets the initial assumptions and can be used as equipment of heavy machines.

The oil market is one of the most important markets for the global economy. Often, oil prices influence the financial results of whole countries and sectors. Therefore, the modeling and prediction of crude oil prices are of high importance. Most up-to-date publications have used daily closing rates in crude oil price modeling, not considering the variability in prices during the day. The application of this kind of price representation leads to a loss of information about the range of price changes during the day, which influences the accuracy of the models and makes them useless in short-term course predictions. In this paper, we introduce the concept of a new state model in a binary-temporal representation, which uses trend analysis, which is one of the main methods used in the prediction of the direction of future changes in the course trajectory. The model described in this paper stands as the first tool that allows for predicting course changes in a given range. The presented work also summarizes the research results of modeling crude oil prices from the last six years, which prove the effectiveness of the mentioned modeling method.