This paper presents an experimental research that proposes to determine the influence of process parameters on CO2 laser cutting of 8 mm thick Hardox 400 steel, for which Kerf has a minimum value. The experimental research was conducted according to a complete factorial plan with laser power, assistant gas pressure and cutting speed as the input parameters, and cutting width as the dependable variable. The Design of Experiment (DOE) consisted of 27 references and was completed with four replicas to determine the variation of the Kerf average. Functional, linear and quadratic relations were determined, which describe the Kerf dependence on the cutting parameters in order to establish the most influential parameter. The results show that the independent parameter with the most significant influence was the laser power, with minimum Kerf obtained if the laser power and the assistant gas pressure were adjusted to average values. The interaction between laser power and auxiliary gas pressure at constant cutting speed was investigated to improve Kerf and reduce the laser processing cost. The study offers the right combination of process parameters that leads to a minimum value of the cutting width.

The study aims to characterize the quality of surface waters in the middle of the river basin Jiu by monitoring physicochemical indicators of their quality, in 2013-2015. In this regard, the pH, dissolved oxygen (DO), biochemical oxygen demand (BOD5) of nitrate (NO3-), nitrite (NO2-), ammonium (NH4+), total phosphorus (Ptotal), chlorides and sulphates from water have been determined. Water of Jiu River and its tributaries of Gorj county have been monitored on representative sections for the evolution of their quality. It was found that the water from natural reservoirs monitored shows an evolution in the limits permitted by the regulations in force except biochemical oxygen demand and nitrites indicators for river Jiu and Tismana and nitrate and chloride content for Gilort River.

Monitoring and control of water quality for human consumption aims to verify if the water available to consumers meets the requirements of relevant legislation and in particular the values of parameters established. The paper presents a study on the assessment of the quality of drinking water distributed in the city of Targu-Jiu by analyzing the following physico-chemical quality parameters: pH, conductivity, turbidity, ammonia, nitrites, nitrates, chlorides, residual chlorine, hardness and aluminum ions content. From the results, it has been found that during 2013-2015, there were exceedings of the maximum permitted levels for residual chlorine and ammonium ion in drinking water samples.

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The goal of this research study is to compare the air quality of two urban locations from Targu-Jiu County namely Rovinari and Turceni. Measurements of SO2 content with automatic analysers were used as a criterion to asssess the air quality. Rovinari and Turceni areas were chosen for this study due to the fact that there are located two thermal power plants considered high stationary sources with an important contribution to regional and global pollution by sulfur dioxide, nitrogen oxides and dust. Sustainable development of fossil fuel power plants cannot be done without the use of technology to limit or eliminate environmental pollution. Studies regarding determination of SO2 content in the monitored areas were performed from January to December 2014. By interpreting the results obtained it can be concluded that the concentrations of sulfur dioxide in the ambient air are below the limit value set in legislation. This is mainly due to the developing of the programs for the progressive reduction of annual emissions of sulfur dioxide, nitrogen oxides and dust which was set up by operators of thermal power plants in order to comply with emission limit values. The high level of SO2 concentration in cold season is attributed to intensifying the burning of fossil fuels for household activities.