Mariana Ciobanu

Particle Size Distribution of the Coal Bottom Ash from the Large Combustion Plant

Human existence is dependent on the consumption of electricity and of thermal energy. One of the environmental problems is represented by the particulate matter with the diameter of less than 2.5 mm derived from combustion of coal. In order to find solutions to reduce emissions at source, the particle size distribution of the coal bottom ash after removing it from the steam boiler of the large combustion plant from Romag Halanga in Drobeta Turnu – Severin area was determined. Dry particle size distribution shows that the major fraction is one that has a particle size of 125 μm. Particle size distribution in the smallest size fraction was performed with laser diffraction particle size analyzer Brookhaven 90 Plus Nanoparticle Size Analyzer. Particle size distribution shows that in the composition of the coal bottom ash were found particles with nanometric dimensions.

Studies on Integrated Waste Management in County Mehedinti

This paper studies the integrated waste management in Mehedinti county. Integrated waste management requires employing several waste control and disposal methods such as source reduction, recycling, re-use, incineration, and land filling, to minimize the environmental impact of commercial and industrial waste streams. Although integrated waste management is designed as a large-scale system, there are things you as an individual can do to support the system.

Research on the Reduction of Greenhouse Gases Emissions to the Enrichment in Carbon of the Iron Powders

The steels elaborated through proceedings that are specific to powder metallurgy have as raw material the iron powder which is enriched in carbon through various proceedings: carburizing in a methane-bearing atmosphere or in a liquefied petroleum gas (LPG)-bearing atmosphere, with the addition of synthetic cementite. In order to be developed as environment friendly technologies, there are made researches in order to reduce GHG emissions.

Studies Regarding Identification and Assessment of Noise Generating Sources in Different Areas of Work

Occupational noise is a complex of sounds of different levels and pitches, with different characteristics (impulsive, pure, audible), rhythmic or nonrhythmic, produced continuously by machines, instruments, devices or discontinuously by vehicles, human voice, during occupational activity. Noise problem is more complex and from this point of view things are far from being good. ”Vladimir Spilda, Commissary for Social Affairs and Egual Chances: Noise effects are not limited only to lossing hearing, He can be causing workplace accidents and increasing stress level.” Noise can be source of risk of workplace accidents, work-related stress and combined with other risk factors at the work place can damage health in both the long and short term.

Study of the Emissions from the Fuel Distribution Stations in Drobeta Turnu Severin

A major source of air pollution is represented by the means of transport. The largest share of gases polluting air comes from motor vehicles, mainly due to their large number. Regardless of the type of motor, vehicles pollutes air with carbon and nitrogen oxides, unburned hydrocarbons, sulphur oxides, aldehydes, plumbum, asbestos, soot, etc. But the activity of trading fuels (diesel, gasoline), lubricants, parts, accessories and auto cosmetics (which are sold in fuel sales and distribution units) is another source of environmental contamination. From this point of view we studied some gas stations located in Drobeta Turnu Severin area, the possibility of soil pollution, waste disposal, safety zone and fire security measures. Air emissions, wastewater discharge, safety and hygiene of jobs were also studied.

Influence of the Mechanical Alloying Parameters on the Elaboration of Sic/Al Nanocomposite Powders

The paper presents the experimental work regarding the elaboration of some nanocomposite powders with higher SiC content. For the research, three types of mixtures were prepared: 90SiC-10Al, 70SiC-30Al and 60SiC-40Al using mechanical alloying (MA) technique. The MA was carried out in a vario planetary ball mill Pulverisette 4 for 5 hours using different conditions: - the shock mode (the main disk speed 400 rpm and the planets speed -800 rpm); - the friction mode (the main disk speed 400 rpm and the planets speed 800 rpm). The resulting mixtures was investigated by scanning electron microscopie (SEM), X-ray diffraction pattern (RDX), energy dispersive X-ray analysis (EDAX) and particle size distribution. After 5 hours of MA it is observed that the mixture obtained in the friction mode conditions have a homogenous structure and the particle size distribution is better than the particle size distribution of the mixture obtained in the shock mode conditions.

Studies Concerning the Microhardness of Sintered Carbon Steels Obtained from Fe and Fe3C Nanopowders

Replacing the graphite with carbides in the mixture with Fe powder may be an alternative technological process, by the fact that as carbides decompose when heated, the carbon is set free and diffuses into the Fe network ensuring chemical and structural homogeneity corresponding to sintered steels. Using cementite nanopowder mix with Fe powder is to ensure a better compaction by pressing, less time to decompose and C diffusion into the Fe network in a remarkably chemical homogeneity. The obtaining procedure for Fe3C consists in direct carburation of Fe powder in a special chamber.

Research on the Elaboration by Sintering in Steps of Carbon Steels Based on Iron and Pure Synthetic Cementite Nanopowders Obtained by Mechanical Alloy

In this paper are presented the experimental results about the elaboration using mechanical alloying of some Fe+Fe3C composites nanopowders and much more sintering in steps. Powder compaction was done by unilateral pressing into a mould of Φ10 mm, at pressing stress of 600, 700 and 800 MPa in a hydraulic press. Following the research was obtained sintered carbon steels with more homogeneous structures regarding the uniformity of carbon distribution and implicitly of constituents structural characteristics of use (mechanical) higher compared with carbon steels sintered by classical methods.