Friction represents one of the major sources of disturbing forces which affect the functioning of the kinematic feed chains from CNC machine tools. Its influence reflects on the positioning precision values, having a negative impact on the table movement and leading to stationary errors, stick-slip motion and trajectory errors. The present paper presents an experimental analysis regarding the influence of the friction forces which appear in the linear rolling guideways on the positioning precision of kinematic feed chains. The rolling guideways present the advantages of a good behavior in terms of axis stability at low speeds and also for achieving high positioning speeds. Concerning the friction coefficient values, rolling and hydrostatic guideways are most suitable for the construction of high speed and high precision kinematic feed chains; in these cases, the friction coefficient has small values, which maintain quasi-constant against the feed rate.

Engine brake systems are based on the concept of spending a large amount of the vehicle’s kinetic energy by releasing pressure from the cylinder. Although an important part of the kinetic energy is used during compression, unless the spring effect of gases is suppressed, a good portion of it is returned to the wheel during the power stroke. This goal can be achieved by releasing of compression just before maximum cylinder pressure is reached. The present paper illustrates investigations upon the exhaust valve opening and closing angles that determine a braking event and their influence upon engine torque.

Tubular thin-walled structures with different shapes of the cross-sections are widely used in various transportation systems as energy absorbing components to dissipate the kinetic energy during violent collisions and crashes. The aims of this paper are to obtain numerical data on the crashing of thin-walled structures made by multiple layers of steel sheets. A series of finite element calculations was carried out on four different models crashed axially in dynamic conditions by using LS_Dyna V971. The effect of the generated fold depth on the peak load and the mean crashing load of these types of structures were also examined.

Increasing the resolution of recent satellite images has become one of the problems for image classification in scientific studies. One way to overcome this problem is to characterize the pixel being classified by parameters measuring the spatial organization of the pixels in its neighborhood. In this study, textural parameters of one-step and two-step encoded images were calculated in the form of a vector. These parameters were subject to the support vector machine classifier to decide which class image is belonging to. Results showed that the encoding method is a proper way to compress an image without losing textural information. It reduces the size of data and thereby reducing the computation time characteristics.

The present paper describes some theoretical aspects concerning the transport of liquid pollutants in the soil and in the aquifer. The pollution of the geological environment represents the modification of the physical, chemical and biological properties of the soil, altering and restraining the soil's usage properties for its constituent elements (soil, geological formations, phreatic aquifers, deep aquifers). The pollution of the geological environment uses water as its main transport agent, in its entire global circuit: in the atmosphere (vapors and precipitation), at the level of the topographical surface (surface water flowing) and in deep levels of hydrostructures (subterraneous flowing).

Increasing the resolution of recent satellite images has become one of the problems for image classification in scientific studies. One way to overcome this problem is to characterize the pixel being classified by parameters measuring the spatial organization of the pixels in its neighborhood. In this study, textural parameters of one-step and two-step encoded images were calculated in the form of a vector. These parameters were subject to the support vector machine classifier to decide which class image is belonging to. Results showed that the encoding method is a proper way to compress an image without losing textural information. It reduces the size of data and thereby reducing the computation time characteristics.