The continuous development of the human society is in a close correlation with the increased consumption of electricity. In the past few years, the thirst for electricity at a global level, has led both to higher levels of pollution and the depletion of fossil fuels. For this reason, the issue of energy efficiency is a priority of energy strategy at national and EU level. In this context, a solution to the above problems is to increase the rate of production of electricity from renewable energy sources. Thus, the paper presents a study of solar radiation as a source of renewable energy, modelling and simulation of photovoltaic systems and validation of data numerical simulations data with the measured data in the Motru area.

The explosion risk is one of the major industrial risks, being present in all units which produce, use, handle, store or transport hazardous substances, products with flammable and explosive properties. Equipment designed for use in potentially explosive atmospheres must be manufactured so that the ignition of the surrounding explosive atmosphere is avoided. One of the ignition sources of an explosive atmosphere is represented by surface temperature. The paper presents the influence of surface temperature in the process of selection of electrical equipment from technological installations operating in explosive atmospheres, as well the test method used to determine it.

Directive 2014/34/EU of the European Parliament and of the Council regulates the placing on the market of equipment and protective systems intended for use in potentially explosive atmospheres. The importance of using explosion-proof equipment (certified in compliance with provisions of standards for electrical and non-electrical equipment) is crucial for avoiding catastrophic explosion-type events which may result in human victims, important material losses or may have significant consequences upon the environment. The current paper addresses a possible scenario of a pressure vessel explosion and the computational simulation and analysis of the dispersion of hazardous substances (toxic or explosive) released in the environment following the explosion-type event, in order to highlight the possible consequences. Such computational simulations may be of benefit for employers, who wish to take proactive measures in order to increase the occupational health and safety level within their activity. In this regard, results of computational simulations can be integrated by the companies in the development of emergency response plans, aiming at minimizing the hazardous effects of the releases of toxic/explosive gases upon the workers and surrounding atmosphere.

The intrinsic safety type of protection significantly increased in complexity during the last decades. Thus, it even provides the opportunity to use highly complex electronic circuits without involving a significant explosion risk within the oil industry or in power plants, but not limited to those two. In order to achieve this performance, the type of protection is based on three pillars: limiting of energy, heat and also fault tolerance. The potential failure of components, connections, and separations are taken into consideration for intrinsic safety evaluations. This paper focuses on scenarios of separation faults in intrinsic safety circuits. The introduction part of the paper provides a summary of requirements for the intrinsic safety type of protection. The separation requirements are also highlighted. This part also explains the "countable" concept regarding the separation faults. The second part of the paper is dedicated to the fault scenarios assessment. Also, this part shows the theoretical model which yields the magnitude of the fault scenarios group. The built-up algorithm for effective localization of the separation faults on a real electronic board is presented in the second part of the paper. This algorithm was implemented using Visual Basic for Applications script and National Instruments Ultiboard software. In the third part of the article, the obtained results are reported and discussed. In order to have a comprehensive image, there was proposed a graph in which links are considered separation distances and elements conductive tracks. Another tool proposed and used was separation distances histogram. The influence of increased finesse on the number of non-countable separation faults was also discussed. The main outcome of the paper is represented by the high impact of non-countable separation faults number over the number of separation failure scenarios. For example, the circuit analysis showed the potential for over sixteen million failure scenarios.

The risk of explosion becomes significant when, in the industrial field, flammable substances such as gases, vapours, mists, dusts, lint and fibres may be present. If they are present in sufficient quantity, the risk of explosion is imminent. On the other hand, the measure of shutting down the technical equipment, in the context of the presence of explosive atmospheres, is not an acceptable measure in all situations. As examples are the parts of installations that have safety functions: ventilation installations, installations for monitoring the concentration of flammable substances and other safety parameters. Explosion protection of technical equipment shall be evaluated and tested in order to validate it. The testing process of the technical equipment for the purpose of explosion protection certification is situated at the confluence of several engineering fields: mechanical, electrical, chemical, etc. The first part of the paper deals with the risk of explosion and presents the explosion protection of the technical equipment. The systematized presentation of the technical equipment tests is performed in the second part of the paper. Among the conclusions it is mentioned that although the field of tests in explosion atmospheres is an interdisciplinary one, its coherence is ensured by the specific standards.