Using the main author's researches on the energies of acceleration and higher order equations of motion, this paper is devoted to new formulations in analytical dynamics of mechanical multibody systems (MBS). Integral parts of these systems are the mechanical robot structures, serial, parallel or mobile on which an application will be presented in order to highlight the importance of the differential motion equations in dynamics behavior. When the components of multibody mechanical systems or in its entirety presents rapid movements or is in transitory motion, are developed higher order variations in respect to time of linear and angular accelerations. According to research of the main author, they are integrated into higher order energies and these in differential equations of motion in higher order, which will lead to variations in time of generalized forces which dominate these types of mechanical systems. The establishing of these differential equations of motion, it is based on a generalization of a principle of analytical differential mechanics, known as the D`Alembert – Lagrange Principle.

This paper presents new formulations on the higher order motion energies that are applied in the dynamic study of multibody mechanical systems in keeping with the researches of the main author. The analysis performed in this paper highlights the importance of motion energies of higher order in the study of dynamic behavior of fast moving mechanical systems, as well as in transient phase of motion. In these situations, are developed higher order time variations of the linear and angular accelerations. As a result, in the final part of this paper is presented an application that emphasizes this essential dynamic aspect regarding the higher order acceleration energies.

Abstract. In recent years there have been many cases of HAVS being reported for people who work in agriculture, horticulture, landscape gardening and forestry. The work described in this paper assesses the transmitted vibration to the human body from a hand guided power tool, means a brushcutter. As it is known the brushcutters induce a high level of vibrations on human operators. Depending by brushcutter's type, exposure time and human subjectivity, we can discuss about the vibration influence on human body. Long exposure to hand-arm vibration, whole body vibration and mechanical overloading is considered a potential cause of professional diseases.

Abstract. The aim of the paper is to present a way to reduce mechanical vibrations that are transmitted to the operator's arm at workplace. This can be done using an innovative device, a damper mounted parallel to the forearm, between the wrist and the elbow.The innovative idea of this paper is the creation (design and realization of the practice) of a vibration attenuator device, which will be mounted along of the forearm; this could minimize the transmitted vibration, by the hand up the arm.The simulation demonstrated that there is a way to reduce the mechanical vibrations for the hand-arm system model chosen. This could lead to the reduction of occupational illnesses that are frequently found in workplaces like this.The conclusions of the experiment performed validated the theoretical results generated by the simulation and have shown that, by using an attenuator device mounted parallel to the forearm (between the wrist and the elbow), we can reduce vibrations along the arm to the shoulder by 50%.

This paper presents the results of the interesting experimental research regarding the influence of the additives over a hydraulic oil i.e. HFE46 (produced by ChemTrend [10]). In this vein, were used two types of additives (resulting two variants of oils denoted as sample C and D respectively) and was carried out a gravimetric determination (using the Timken test) analysing the hydraulic oils lubricating proprieties. Also, measurements regarding the vibrations in the tribotechnical system-TTS were conducted.