Abstract:The concentration of five soil heavy metals (Pb, Co, Cr, Cu, Hg) was measured in forty sampling sites in central Transylvania, Romania, regions known as centres of pollution due to the chemical and metallurgical activities. The soil samples were collected from locations where the ground is not sliding and the probability of alluvial deposits is small. The concentration of heavy metals was measured by using the Inductively Coupled Plasma Spectrometry method. Data were verified by using the Neutron Activation Analysis method. In some locations, the concentration for the investigated heavy metals exceeds the concentration admitted by the Romanian guideline. The highest concentration of lead (1521.8 ppm) and copper (1197.6 ppm) was found in Zlatna. The highest concentration of chromium was found in Târnăveni (1080 ppm). The maximum admitted concentrations in the sensitive areas revealed to be exceed from five to forty times.

Abstract:The paper presents a chemical composition analysis of the gases emanated from geothermal sources in the Herculane Spa area (Romania). The upper homologues of methane have been identified in these gases. An ion-molecule reaction mechanism could be implicated in the formation of the upper homologues of methane. The CH 4 + ions that appear under the action of radiation are the starting point of these reactions. The presence of hydrogen in the emanated gases may be also a result of these reactions.

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The activation energy of the local dynamics of the polymeric segments is calculated from the spin–lattice relaxation time, measured by NMR method. A new algorithm of analysis of the experimental data is proposed in order to increase the accuracy of the evaluation of this parameter. This method was applied for some polyisoprene- C 7 D 8 solutions and for the molten polyisoprene.

The relaxation of the transverse magnetization of the protons attached to polymeric chains and pseudo-solid echoes were observed for molten polyizobutyl and for polyizobutyl- C 7 D 8 solutions by NMR method, in a large temperature domain. The analysis of the shape of the pseudo-solid echoes leads to the possibility of evaluating the function that characterizes the contribution of the fluctuation of the entanglements to the relaxation of the transverse magnetization. The modification of this function is associated to the perturbation of the superposition property of the relaxation curves and induces changes of the properties of the pseudo-solid echoes.