535 research outputs found
ENERGY MARKET AND THE PERMANENT MANAGEMENT, A POSSIBLE SOLUTION FOR SMALL HYDRO-POWER PLANTS
The paper structured in five parts, aims to highlight the importance of an integrated management as to ensure a high efficiency and a smaller time to recovery of the investment for a small hydropower plant (SHP). In the context of sustainable development of the energy sector, due to the shortage of budgetary funds, a large amount of interests of all participants in the process must be correlated: the interests of investors - which provides funding and execution; general economic and social interests of local communities, the regulated legislature protected by state institutions. First is analyzed the importance of the study of the infrastructure energetic efficiency, in the current economic context, followed by a presentation of the optimum solutions of planning of such SHP. In third chapter are analyzed some factors that influence the optimum functioning of the SHP and in the fourth part the benefits of a real energetic management. In final chapter is presented the numerical model of the combined management and some obtained results. The paper ends with some conclusions and references
THEORETICAL ASPECTS AND NUMERICAL MODELLING FOR LONG TERM PREDICTION OF ABL AND WIND DISTRIBUTION IN POWER FARM
The paper is structured in seven parts, the
last for few conclusions and finally some references. It
is based on concrete measurements and observation
during around 2 years. First is presented an
introduction of the actual situation. In part two are
mentioned the methods and hypotheses in evaluation
of wind velocity distribution in boundary layers for
atmospheric air, taking into account the roughness of
ground surfaces. It is mentioned a concrete area, south
part of Moldova. In third part is presented a solution
for the geodetic model and finally are selected the
altimetry solution. In chapter four is determined the
influence of air density, temperature and pressure on
wind turbine functioning. In the next chapters are
presented the numerical model with special boundary
conditions, taking into account different value of
roughness and finally the obtained results. It is also
estimated velocity variation during day-night. Finally
is presented the vertical distribution of horizontal
wind velocity for a wind farm, obviously important
due the power of turbine (around 3 MW each one).
Some conclusions and references are also mentioned
Seismogeological Features of the Crust in Romania
The Romanian area consists of old consolidated units of pre-Alpine age (the Moesian, Moldavian and Scythian platforms) and Alpine orogenic units (the Carpathian arc and North-Dobrudjan orogen). General seismogeological peculiarities of the pre-Alpine tectonic units are presented, as well as some structural characteristics of the Transylvanian Basin and the Pannonian Depression. Both shallow and deep seismic reflection/refraction data as well as log information and some potential field data were used for the investigation of the crustal structure. The varibility in the seismogeological pattern and crustal thickness shown by the different tectonic units is due to the differences in structure and lithology as well as to differences in crustal age. Some general characteristics are presented as an overall seismogeological image
Wide complex tachycardia in an elderly woman due to Ebstein\u27s anomaly with two accessory pathways
EVALUATION OF HEAVY METALS CONTENT IN EDIBLE MUSHROOMS BY MICROWAVE DIGESTION AND FLAME ATOMIC ABSORPTION SPECTROMETRY
The aim of this work was to determine the heavy metal (Cd, Cr, Ni, Pb, Mn, Zn, Fe and Cu) content of the fruiting bodies (cap and stipe) of four species (Amanita caesarea, Pleurotus ostreatus, Fistulina hepatica and Armillariella mellea) and their substrate, collected from forest sites in Dâmboviţa County, Romania. The elements were determined by Flame Atomic Absorption Spectrometry (FAAS) after microwave assisted digestion. From the same collecting point were taken n = 5 samples of young and mature fruiting bodies of mushrooms and their substrate. The high concentrations of lead, chrome and cadmium (Pb: 0.25 – 1.89 mg.kg-1, Cr: 0.36 – 1.94 mg.kg-1, Cd: 0.23 – 1.13 mg.kg-1) for all collected wild edible mushrooms, were determined. These data were compared with maximum level for certain contaminants in foodstuffs established by the commission of the European Committees (EC No 466/2001). A quantitative evaluation of the relationship of element uptake by mushrooms from substrate was made by calculating the accumulation coefficient (Ka). The moderately acid pH value of soil influenced the accumulation of Zn and Cd inside of the studied species. The variation of heavy metals content between edible mushrooms species is dependent upon the ability of the species to extract elements from the substrate and on the selective uptake and deposition of metals in tissue
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Maleimide-functionalised PLGA-PEG nanoparticles as mucoadhesive carriers for intravesical drug delivery
Low permeability of the urinary bladder epithelium, poor retention of the chemotherapeutic agents due to dilution and periodic urine voiding as well as intermittent catheterisations are the major limitations of intravesical drug delivery used in the treatment of bladder cancer. In this work, maleimide-functionalised poly(lactide-co-glycolide)-block-poly(ethylene glycol) (PLGA-PEG-Mal) nanoparticles were developed. Their physicochemical characteristics, including morphology, architecture and molecular parameters have been investigated by means of dynamic light scattering, transmission electron microscopy and small-angle neutron scattering techniques. It was established that the size of nanoparticles was dependent on the solvent used in their preparation and molecular weight of PEG, for example, 105 ± 1 nm and 68 ± 1 nm particles were formed from PLGA20K-PEG5K in dimethyl sulfoxide and acetone, respectively. PLGA-PEG-Mal nanoparticles were explored as mucoadhesive formulations for drug delivery to the urinary bladder. The retention of fluorescein-loaded nanoparticles on freshly excised lamb bladder mucosa in vitro was evaluated and assessed using a flow-through fluorescence technique and Wash Out50 (WO50) quantitative method. PLGA-PEG-Mal nanoparticles (NPs) exhibited greater retention on urinary bladder mucosa (WO50 = 15 mL) compared to maleimide-free NPs (WO50 = 5 mL). The assessment of the biocompatibility of PEG-Mal using the slug mucosal irritation test revealed that these materials are non-irritant to mucosal surfaces
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