ANTHROPIC IMPACT ON AIR QUALITY IN THE DANUBE REGION

There were monitored by data acquisition both in summer and winter period, the concentrations of pollutants - SO2, NO2 and particulate matter (PM10) – existing in air on the territory of 6 counties bordering the Danube. After processing and analysis of collected data have been found that: SO2 pollution may be due primarily burning fuel with high sulfur content and / or industrial activities for carbonic products (anodes for obtaining the electrolytic aluminum, graphite electrodes etc.); pollution with NO2 comes primarily from automobile exhaust gases; particulate matter pollution may be due both loess soil (high winds in dry periods) characteristic of the area

DURABILITY OF ANTICORROSIVE PROTECTION COATINGS FOR ELECTRO-ENERGETIC EQUIPMENT

Determining the working life of the anticorrosive protection layers is of great importance for electro-energetic installations. In order to assess the durability of the paint layers have been achieved films of 100 ÷ 120µm from six different commercial types of paint. After polymerization/drying, the dielectric characterization of the obtained films has been achieved by dielectric spectroscopy - both before and after their exposure to controlled doses of UV radiation. The experimental results have been revealed that the polymer matrix of the painting materials, over a critical dose of UV radiation (specific commercial sort), suffers a complex process of aging after which the anticorrosive insulation capacity decreases

Structure and Adhesive Properties of Nanocomposites Based on Functionalized Nanofillers

Nanocomposite samples of the copolymer of ethylene and vinyl acetate containing carbon nanofibers and nanotubes have been prepared by mixing in solution. In order to improve interfacial interactions in the polymer-nanofiller system they were subjected to a preliminary chemical functionalization. The efficiency of functionalization was estimated by the IR spectroscopy. The X-ray diffraction and strength characteristics of the obtained nanocomposites filled by the untreated and functionalized carbon nanofibers and nanotubes with different filling degree were compared

STUDY OF SOME INSULATING OILS AGING BY THERMAL CYCLING

The By gravimetric measurements and coupled thermal analysis techniques (DTG+TG+DTA) the aging of different sorts of insulating oil was studied by thermal cycling between -400C and 850C. The experimental results showed that, during the thermal cycling of the investigated mineral oils, their composition changes due to the volatilization of the volatile fractions (mass losses between 3.9% and 5.8%), unlike the investigated vegetable oil that showed a mass increase of approx. 0.66%. It has also been found that the mineral oils can be ensure a safe operation, without significant changes up to a maximum of 1000C, as long as investigating vegetable oil can be used without degradation risk up to 2000C

INFLUENCES OF 50HZ ELECTRIC FIELDS ON GROWTH AND MULTIPLICATION OF SOME MICROORGANISMS

By dielectric spectroscopy and specific microbiological techniques have been studied the development (cell multiplication) of Saccharomyces cerevisiae and Aspergillus niger growing and multiplication - both on culture media with sucrose and on those with starch. The experimental results have been revealed that the biochemical processes of the studied biomasses have significant changes in certain frequencies in the range 1 - 160Hz, characteristic of the different species/metabolized carbon source, respectively species/ metabolized carbon source/ development phase. It has also been found that in the case of Saccharomyces cerevisiae, the electric field of 50 Hz up to 20V/cm reduces the length of the LAG time and increases the growth rate of intensive increasing phase. Cultures of Aspergillus niger on culture medium with sucrose are stimulated (increasing the spores production by approx. 50% and reducing the maturity time) of 50Hz signals up to 15V/cm. Electric fields higher than 30 V/cm in all media and investigated cultures carry on to the growth reduction / multiplication - up to a complete inhibition of growth at approx. 50V/c

On the relationship between optical and structural properties of polymer films modified by carbon micro and nanopartciles

The studies were concentrated on investigations of optical and structural characteristics of polymeric films filled by carbon micro and nanoparticles. Light transmission in the region of visible spectra of the films based on gelatin and polyvinyl alcohol was found to be almost independent of the wavelength. Carbon particles appeared to have no intrinsic absorption bands within the UV region. In the case of aggregation, nanotubes start to form clusters with an optical fractal structure, while the films display spatial fluctuations in transparency accompanied by deviations from the Bourguer-Lambert-Beer law. In contrast to nanoparticles, microparticles reduce the roentgen level of crystallinity of the films

A REVIEW ON COUNTER-ROTATING WIND TURBINES DEVELOPMENT

On a dynamic energy market characterized by the constant energy demand increase and economic as well as environmental constraints, the study and development of efficient conversion systems of wind’s energy has been approached by a considerable number of researchers. Given the modern economic and environmental challenges regarding the energy production and consumption, an advance in the research of innovative or improved wind energy conversion solutions has been registered. The objective of this paper is to provide a comprehensive, but not exhaustive overview of research achievements in counter-rotating wind turbine systems development, characterization and use. The review presents the first theoretical results that led to the counterrotating wind turbines development as well as the related methods used for investigating their performance. Valuable results have been found within various studies, which are carried out for different testing systems and conditions. Furthermore, there is still need of extensive studies, taking into account that the counter-rotating wind turbines have to prove their reliability in real operating conditions

Sciatic nerve schwannoma: Case report

Background. Schwannomas are common, benign tumors of the sheath of peripheral nerves. Sciatic schwannomas are rare. PURPOSE: We report a case of a large sciatic schwannoma, emphasizing the role of nerve preservation. Material & methods. A 54 years old female was admitted in our clinic for persistent right sciatalgia, and right L5 and S1 motor loss, symptoms lasting for almost 2 years. Patient underwent surgery in a different department, but the operation was stopped, because of excessive bleeding. Results Neurological examination revealed right sciatalgia, right L5 and S1 motor loss and diminished ankle jerk reflex, but failed to reveal relevant symptoms for disc herniation clinical diagnostic. Thigh CT-scan and MRI showed a large (70/80/75 mm) encapsulated, contrast-enhancing tumor, located in the middle third of the posterior thigh, in intimated relation with the sciatic nerve. Associated chronic myeloproliferative syndrome required oncological treatment and surgery postponement. We performed a subtotal resection of a large, solid tumor, infiltrating the sciatic nerve on 4 cm length, with anatomic integrity of sciatic preservation. Histopathological examination found cellular schwannoma. Outcome was favorable, and on follow-up examination the patients present no additional deficits and thigh CT-scan showed any evidence of tumor regrowing. Discussions & Conclusions. Diagnostic is challenging, in many symptoms are attributed to degenerative spinal pathology. Any persistent sciatlagia, with irrelevant lumbar MRI must raise the suspicion of a peripheral sheath tumor, and must be further investigated. Surgery is very demanding and associated co-morbidities must be treated prior surgery. Preserving the integrity of the sciatic nerve, assure favorable outcome, with no additional neurological deficits

GASSING OF THE ELECTRICAL INSULATING FLUIDS - A DETERMINANT FACTOR OF THE TRANSFORMERS SAFETY IN OPERATION

The influence on the quality of the electrical insulating fluids on the safety in operation of the transformers has been evaluated. After processing the comparative experimental data obtained by gas chromatography technique on 5 different sorts of electrical insulating fluids (a sort of vegetable oil with high oleic content and with addition of 0.5% antioxidant "functional model" - compared with two commercial sorts of mineral oil, 1 mainly vegetable commercial oil, 1 commercial synthetic ester), thermal aged in contact with electrical insulating paper and copper for electrical use, at 110 ± 3 °C for 1000 hours in closed vessels (limited access to atmospheric oxygen) it has been found that at the transformers filled with mineral oils, the risk of explosion and fire is approx. 10 times higher than those filled with synthetic or vegetal ester. It has also been found that the ageing of the insulation paper is approx. 15 times slower in the synthetic and natural ester than in the mineral oils normally used in transformers