International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The future development of the renewable energy sector in Bulgaria is already set by the European Commission in the “Energy Map of Europe – 2050”. The goals of the Green Deal should not predominant the goals of environmental protection and reverse. Bulgaria should ensure balance and sustainability in the development especially of wind energy sources due to the fact that most energy potential areas fall in the protected areas and territories by Natura 2000. The biggest such conflict observed in that report is the region of North- Eastern Bulgaria. The production of electricity from wind is one of the activities that has a potential impact on birds. For this reason, the subject of this study analyses the available data and summarize the birds’ impacts of wind generators in the region of North – Eastern Bulgaria.

In order to determine the total spatial and temporal scale of the propagation of anthropogenic sources of noise, it is necess ary to identify them, which can be achieved by comparing underwater and sea surface observation data. For this purpose, it is necessary to determine the direction to the noise object in a function of time. In the development of a passive hydro-acoustic system positioned on the seabed for the detection, classification and determination of the direction to an underwater object, an adaptive processor sh all be designed, examined and experimented to dynamically determine the weighting factors of a two-element antenna grille according to the criteria of the minimum of the average square error and the maximum of the signal noise ratio

An internal combustion engine is considered as a material body, which characterized by inertial, elastic and dissipation properties, which are impacted from various forces. Oscillatory motion of a material body occurs in accordance with spectral characteristics of force and frequency responses of the system. The outer surface of the engine generates acoustic energy and causes mechanical noises.

The paper dwells on determining acoustic energy in accordance with the acoustical radiation rate if the radiation coefficient of the object observed is known. Also, the sound of the engine is presented as a sum of its separate acoustic powers, and there is determined the acoustic radiation coefficient of the engine for the entire surface, by using the acoustic radiation coefficient of each surface. Simultaneously, there is determined the vibro-energy distribution in the engine design, the assessment of which is made by means of the energy-transfer coefficient, which generates the frequency responses of vibro-acoustic parameters.

Drivers of road-building machinery are subjected to noise pollution variable nature of the noise. The purpose of this study is to show the values of noise experienced by drivers of different types of road-building machinery (trucks, excavators, tractors).