This paper presents a detailed kinematic analysis of a double-toggle jaw crusher used for the primary crushing of hard and bulky materials. The study introduces an innovative mathematical modeling method for the motion of the mechanism’s components, eliminating the need for traditional decomposition into structural groups. General equations are developed to determine the positions, linear velocities, and angular displacements of the moving elements, providing a solid foundation for equipment design and study. The generated mathematical model was validated using real-world dimensions of an SMD-117-type jaw crusher and by comparison with simulation results obtained from Mathcad, Linkage, Roberts Animator, and GIM software. The results demonstrated a high degree of agreement between the calculated and simulated trajectories and linear velocities. The analysis of angular displacements and linear velocities confirmed the cyclic nature of the mechanism’s motion, characterized by sinusoidal variations and low oscillations, which are relevant for assessing variable loads. Through its rigorous approach and multi-source validation, the research makes a significant contribution to the development of more efficient, durable, and adaptable jaw crushers for modern industrial requirements.

In this paper, a study that describes the mathematical analysis of a mechanical gripping system with a lifting-tong-type mechanism is presented. The study involves the geometrical analysis of the investigated mechanism. What distinguishes this work from other studies in the specialized literature is the way the analysis of the mechanism under study is carried out. Specifically, the working methodology proposes the analysis of the entire mechanism and not its decomposition into structural groups, thus obtaining complex mathematical equations. By using values, the mathematically obtained results were able to describe the movement of the mechanism’s components, as well as the variations in their velocities. To verify the correctness of the results, a simulation was carried out using the Linkage simulation software.

This article presents a comparative study of two different kinds of processes that produce oscillatory motion on a work surface during the mechanical separation process. The investigation began with determining the trajectory produced by the oscillating separator’s active component of the classical drive mechanism. Based on this, a second mechanism—the six-bar mechanism—was created using the WATT program, and a mathematical analysis was conducted. The comparative examination of the two mechanisms was carried out using OriginPro, Mathcad, and Roberts software. This study’s findings all point to the same conclusion: the newly developed mechanism produces the same trajectory as the classical mechanism when viewed through the lens of the reference element, or the element that causes the oscillatory movement. However, when looking at the operating parameters, there was a noticeable difference in the movement’s speed and the angle of the crank when producing its maximum speed. Theoretically, this new mechanism increases the speed at which solid particles move across a work surface. However, this difference cannot be characterized as positive or negative because further research is required to determine how the nature of solid particles and the work surface’s inclination affect this process, in addition to this mechanism. The identification of the mathematical equations of motion for the constituent parts of the mechanism under study is the novelty produced of this paper.

LCA methodology is often used in public procurement decision making. The European Commission introduced Life Cycle Costing (LCC) in 2014 to support this methodology. LCCs take into account costs incurred during a service, work or product’s lifetime. Application management techniques of LCC offer a better awareness of the factors that influence the resources and costs in the case of procurements. The identification of the factors that influence the costs is the main key of the LCC tool. In such a way, the life cycle management is focused on efficient purchasing. The awareness levels of the LCC criteria influence the cost and will also highlight other aspects of existing products that could benefit from the involvement of life cycle management. Taxi transport services (as an alternative to public transportation) are a sector of the economy with a good income when acquisitions are properly carried out. When the acquisitions are analyzed, governmental and local regularizations should be taken into account. Today, cities, as well as small towns, look forward to improving the quality of life of the citizens and reducing pollution. The acquisitions of buses/cars for public use must be carried out with respect to the required performance of the cars. On the one hand, the municipality should be in line with the European Commission’s policy; on the other hand, it should be in line with the state’s public procurement requirements. An acquisition must also be reasonable in terms of price, lifetime, environmental impact, circular economy and meeting citizens’ needs. The goal of this paper was to analyze the acquisition of cars for taxi services from the perspective of public procurements. The study was performed with the help of the Taxi LAL company from Bacau County. The LCC techniques were applied to identify the most “acceptable” as well as the most “profitable” choices for taxi services. For a better understanding of the problem, within the present paper the mechanism of cost assessment for a product modernization was exemplified.

The elasticity of bearings as well as their clearance have an essential influence on the total arrow and, therefore, on their own pulsation. In most of the literature, this elasticity is neglected in the calculation of shaft deflections. In some work, the elasticity of the bearings has been taken into account when calculating the deflection of the mixing device shaft, but this has been carried out on the basis of a high degree of customization: the behavior of the bearings has been considered linearly elastic, which does not correspond to reality because according to the elastic response of the bearing, it is a nonlinear function of the radial displacement. When the shaft of a mixing device operates in a pressure vessel, at the outlet of the pressure vessel, the shaft is provided with a sealing device, which can be considered a third bearing. This aspect is also not taken into account in the calculation of the shaft’s deflection, which leads to a certain degree of error in its determination. This study aims to highlight the influence of the elasticity of the bearings and the sealing device on the stiffness of the shaft and to propose a method that supports a calculation program for calculating the elastic line of a vertical cantilever shaft, considering the role played by the bearings in the case that they behave nonlinearly and the sealing device as the third bearing. This problem was solved both by applying our own method and with the help of the FEM.

In the Tazlau Basin there was a really strong anthropogenic impact. Many areas have almost totally been deforested, the grazing and agriculture have extensively and irrational been practiced, underground reserves have been exploited, too etc. The expanding of settlements along the rivers and building of modern communication routes along beds favored the phenomena of flooding and destruction of hydraulic works. These all aspects led to frequent occurrence of risk events: erosions, landslides, degradation of the rivers beds, pollution of air, water, vegetation, soil, etc. The paper identifies anthropogenic risk factors from Tazlau Basin, and proposes analyzes of the consequences and the measures to avoid these ensuing consequences.