[en] Prolonged treatments in oxygen lead to a substantial increase of the diamagnetic signal of superconducting YBa₂Cu₃Osub(x) due to the decrease of the amount of defects and to the development of Josephson-like contacts between homogenous superconducting regions in the sample. The superconducting-glass features are expected to be considerably reduced in well crystallized samples at least at liquid nitrogen temperature. (authors)

[en] Some experimental results concerning the synthesis of high-temperature superconducting materials in the Y-Ba-Cu-O system and their electrical, magnetic and structural properties are presented. (authors)

[en] Boric acid corrosion of pump and valve fasteners in pressurized water reactor (PWR) power plants can be prevented by implementing appropriate fastener steel replacement and extended inspections to detect and correct the cause of leakage. In this paper a three-phase corrosion protection program based on system operability, outage-related accessibility, and cost of fastener replacement versus maintenance frequency increase is presented. A selection criteria for fastener material is also presented. Degradation or failure of pressure retaining fasteners at pumps and valves has been reported in several areas exposed to leakage of closures in long-term service. The resulting boric acid corrosion experienced in PWR systems is defined as an accelerated process produced when water evaporates from leaking coolant. The primary detrimental effect of boric acid leakage is wastage (or general dissolution corrosion) of low-alloy carbon steel fasteners

[en] This paper presents the energy balance for Romania and possible evolution of the energy system for various scenarios of the future energy supply/demand equilibrium. The different strategies for electricity and heat generation programs take into consideration the fuel prices evolution (coal, gas, oil) on the international market, the evolution of the capital cost of different technologies and the cost of the emission control. The impact of these strategies over the primary energy supply and the future national energy policies is also presented. 1 ref., 3 figs., 3 tabs

[en] To establish a possible relation of dependency between pulmonary hypertension (PHT) and several factors, with the evaluation of their predictive potential, in Graves' disease. Methods: For identifying the factors implied in producing PHT and for evaluating its reversibility, we made echocardiography exams, sessions of monitoring the blood pressure during 24 hours and biological test in a group of 42 patients with Graves’ disease (group H), comparing them with themselves in a euthyroid status (group E, n=25) and with a control group (group C, n=25). In order to analyse the relation of dependency between pulmonary hypertension (PHT) and the factors identified in the H group, we used both the simple linear regression method (polynomial of degree 1) and the non-linear regression method (polynomial of degree 2, 3) for establishing one model of functional dependency. We used the values of the coefficients of correlation r (degree of dependency) and of determination R2 (the type of dependency). The statistical test (F-test, AIC criterion, test t) was applied by choosing the most appropriate model of determination, with a higher predictive potential. Results: We identified PHT at 47.6% of the patients with Graves’ disease. Once the euthyroidism status is obtained, PHT is normalized. While inducing PHT, we identified a strong relationship of dependency on several possible new factors such as: pre-treatment period, age, level of the thyroid stimulating hormone receptor antibody and values of systolic blood pressure, besides the already known ones (high level of thyroids hormones, cardiac output, pulmonary vascular resistance). Conclusions: The non-linear model best explains the relation of determination between pulmonary pressure and those factors having a better predictive potential (from 51% to 90%), compared with the linear model, the only exception being the age factor and the systolic blood pressure, where both models seems to be appropriate. (author)

[en] It has been recognized that the boric acid corrosion wastage of pump and valve fasteners is mainly a maintenance problem. Therefore, the nuclear utilities of pressurized water reactor (PWR) power plants can prevent this damage by implementing appropriate fastener steel replacement and extended inspections to detect and correct the cause of leakage. A 3-Phase Corrosion Protection Program is presented for implementation based on system operability, outage related accessibility and cost of fastener replacement versus maintenance frequency increase. A selection criteria for fastener material is indicated based on service limitation: metal temperature and preloading. (orig.)

[en] There will be a significant growth of the electricity demand in Romania over the period 2005-2015; therefore, it will be necessary to devise an optimized strategy for electricity generation in order to ensure the economic development of the country and to achieve a standard of living that is similar to that of people in western European countries. For the development of electricity generation capacities in Romania it will be necessary to consider the security of supply of primary energies as well as the prospects of utilizing clean technologies in order to fulfill the requirements for environmental protection. In view of the medium and long term forecasts of the electricity demand in Romania, it is expected that the import of fuels will increase. Therefore, it is very important to make comprehensive comparative assessments of different energy chains for electricity generation, incorporating health and environmental issues in the planning and decision making process. Since 1994, Romania has participated in the DECADES project and has used the DECPAC software to work out a country specific database. It was found that the 'least cost' development programme of power plants comprises new plants equipped with 660 MW combined cycle natural gas units. All expansion options and the fuel price escalation on the international market were taken into account. The nuclear power alternative is attractive as regards environmental protection and because it is not possible for Romania to secure the necessary gas supply. (author). 6 refs, 7 figs

[en] Thin organic films based on poly-methyl-methacrylate (PMMA) polymer have been obtained by pulsed laser deposition (PLD) on silicon substrates. The films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and Raman spectroscopy (RS). We observed that the film composition and structure depend on the laser fluence and on the temperature of the substrate during deposition

[en] Silicon substrate is widely used for the deposition of thin film samples. During last year extensive research of new materials for micro and opto-electronics were carried out. False peaks can appear for films with low texture deposited on silicon wafers. Spurious peaks in the diffraction pattern originated from the silicon substrate have been observed in carbon-nitride films and this prevented the correct identification of the structure of these films. In X-ray diffraction (XRD) measurements, in many cases, a very strong escape-peak was observed, situated in the region of the first sharp diffraction peak specific to amorphous chalcogenides. The escape-peak exhibits an asymmetric shape, and is very sensitive in intensity to the wafer's position in its own plane. We carried out a detailed study related to the effect of the position, orientation, accurate crystallographic cut of the silicon wafer, on the X-ray diffraction diagram of a thin film deposited on the wafer. The origin, the condition of appearance and the method to minimize the escape-peak are discussed. The monochromator effect of the perfectly oriented silicon wafer was evidenced and the minimum deviation from the crystallographic cut, necessary for a clean diffraction pattern was estimated. Two methods were proposed with the aim to minimize or to eliminate the distortions induced in the X-ray amorphous pattern by the silicon wafer substrate: a. the rotation of the silicon wafer with an appropriate angle, that must be found before thin film deposition according to the condition of minimum substrate effect; b. use of lower voltage applied to the X-ray tube; in this case the escape peak is not activated. Careful arrangement of the experimental conditions will avoid many misleading interpretations that can be found in many papers related to new advanced materials for microelectronics and optoelectronics, or hard CN materials prepared as thin films. (authors)

[en] Full text of publication follows: Beginning with 1950 the uranium mining industry was developed in Romania. Banat region was one of the most important metallogenic zones of the country and its exploitation began on 1962. Between 1988 and 1998 uranium exploitation activity was ceased due to the uranium ore deposits exhaustion. Therefore, between 2000 and 2004 the entire mining zone closure, ecological rehabilitation and decommissioning documentation was conceived. The proposed solutions were elaborated according to the Romanian Environmental and Nuclear Authority concerning the terrain, equipment, devices and buildings unrestricted utilization after the mining site decommissioning and ecological rehabilitation. The radioactive sources (dumps, contaminated soil, and mining waters), radioactive pollution spreading pathways and the affected target groups were identified based on the research studies carried out in order to elaborate the mining area closure, decommissioning and ecological rehabilitation technical project. The closured mining zone map with these elements positions and their radioactive potential, namely the uranium and radium content, gamma radiation and radon concentration is presented. The present paper shows the assessment of the supplementary effective doses received by the population from the critical groups, which are calculated for the following three distinct situations: a) at the moment of uranium ore exploitation activity closure; b) during the closure, decommissioning and rehabilitation workings time; c) after the site rehabilitation and remediation. Each moment is characterized by a map, which presents the radioactivity levels discussed for four distinct scenarios. Each one of these scenarios is characterized and justified for its chosen. For each one of the scenarios there are presented maps with the pollution sources and pathways and there are calculated the public supplementary effective doses before and after site restoration. During the closure, decommissioning and rehabilitation workings time, it is presented for the working staff the calculation of the supplementary effective doses, which it is exposed to, related to the working type, as it follows: - at the radioactive material relocation: 1.01 mSv/year; - at the stepping, leveling and encapsulation workings: 2.77 mSv/year; - at the underground equipment decommissioning: 1.12 mSv/year; - at the building demolition and underground equipment decommissioning the supplementary effective dose is: 0.5 mSv/year. After site remediation and clean-up of contaminated areas the limits stipulated by the Romanian Nuclear Authority are respected, as it follows: - the ecological restored surface areas and dumps fulfilled the conditions according to which specific activity is less or equal to 0.2 Bq/g and the gamma rate dose is less or equal to 0.3 v/h; - the hydrographic network waters conform to dose values stipulated by the Romanian Nuclear Authority. The calculated supplementary effective doses for the workers did not exceed the value of 20 mSv/year and the ones calculated for the population after the remediation are not exceeding 1 mSv/year. (authors)