Rotary seed sorters used for wheat processing show some functional advantages in eliminating persistent contaminants, especially due to the more aggressive treatment applied to the processed material. The objective of this paper was to design a new constructive subassembly that would increase the performance of rotary sorters used for extracting various contaminants from seeds. By testing a pilot stand that reproduces the operation of a professional equipment and developing mathematical models that fits the main operating parameters, it was possible to identify the new characteristics needed to improve cylindrical sieves and to optimize the functioning of this equipment.

This paper presents theoretical and experimental research studying the influence of process parameters on the quality of biomass pellets. A validated mathematical model was developed, expressing the density of biomass pellets as determined by moisture content, compression pressure, process heat, the initial density of the material, pelleting speed and initial volume of the material. The experiments for determining the influence of these parameters on the compression of biomass into pellets and optimizing the process were conducted on a heated single pellet compression device, using fir sawdust as raw material. To describe and study the process, four input and control parameters were varied—raw material moisture, pelleting speed, maximum force applied and pelleting die temperature. From the experiments, it was noticed that overall, moisture and pressure have the most important effect on the compression process and pelleting speed, and heat applied also affected the process. Pellet density decreased when pelleting speed and material moisture increase and the density increased with a higher compression pressure and higher heat during the process.

This article presents the way to obtain the structural model for elementary linear-elastic static analysis of equipment to prepare the germinative bed in strips main resistance structure. Also, to prove the functionality of the structural model obtained, the structural analysis results for the linear elastic static test are presented. These results are useful for estimating the safety factor and for assessing the behaviour in major overstress situations at the main part of the machine. Structure dynamics is a very broad discipline that uses a huge arsenal of theoretical and experimental methods to solve a fundamental problem of structures: the dynamic response to variable tasks over time. Vibrations, and especially vibration in resonance modes, are problems that occur frequently in large structures. As large structures with large numbers of components cannot be optimally engineered for resonant regimes, it is often done to resolve structures or improve them by using the modal analysis of the mathematical models of these structures. The usefulness of this analysis is particularly evident in the testing phase and even in the first stages of operation, when it is necessary to improve the working regime of a product of the type analyzed. The main results of the static linear-elastic structural analysis are: the values of the reactions in the holders, vector field distribution of the relative -resultant displacement in the structure, tensor fields' distribution of the specific deformation and the Cauchy stress tensor in the same structure. Also, an important result for the structure safety is the distribution of the safety factor. The analysis of the equipment's own spectrum allows proper identification of the main frequencies, at which a resonant working regime can occur.

In the past few decades, size and weight of agricultural machinery have increased significantly, and as a consequence, the severity and depth to which the stress is transmitted into agricultural soil have increased. The objective of experimental determinations was to study the influence of some factors characteristics to compaction: tire inflation pressure, wheel load and contact pressure on the contact area between tire and soil, as well as 2D and 3D mapping of pressure distribution in the footprint. The front tire of the U445 Romanian agricultural tractor was tested at five tire inflation pressures: 100, 150, 200, 250 and 300 kPa, obtaining contact areas between 0.0252 – 0.0349 m2 and contact pressures between 98 - 136 kPa.

The aim of the study was to identify new mathematical models and strategies that can characterize the behavior of pollutants accumulating in the soil over time, considering the special characteristics of these chemicals that cannot be degraded or destroyed easily. The paper proposes a statistical model for assessing the accumulation of Zn in the lettuce (Lactuca sativa L.), based on three indicators that characterize the development of lettuce plants over time. The experimental data can be used to obtain interpolated variations of the mass increase functions and to determine several functions that express the time dependence of heavy metal accumulation in the plant. The resulting interpolation functions have multiple applications, being useful in generating predictions for plant growth parameters when they are grown in contaminated environments, determining whether pollutant concentrations may be hazardous for human health, and may be used to verify and validate dynamic mathematical contamination models.