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Zirconium alloys, are usually used as fuel cladding materials in VVER (water-cooled, water-moderated energy reactor) type reactors, mainly, due to their low neutron absorption cross-section, desirable mechanical properties, and good corrosion resistance under reactor operating conditions. During exposure to water at high temperature, water reacts with zirconium alloys, which results in the production of an oxide layer. The entire area of corrosion along with the accompanying absorption of hydrogen in the zirconium metal matrix has attracted a lot of attention when the performance of the core components as well as the operation of the reactor is emphasized. The growth of the zirconium oxide layer plays a destructive role in decreasing thermal efficiency of the reactor by restricting the inlet temperature and chemical properties of the coolant. The present study aimed to develop a computer code to predict long-term water side corrosion weight gain, oxide thickness and determine the concentration of absorbed hydrogen in VVER-1000 reactors during normal operating conditions. The proposed model can be utilized to estimate the pre-transition and post-transition corrosion weight gain and the oxide thickness in operating conditions.

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Composting has always been considered a way to optimize use of biodegradable wastes. The point which is perhaps less noticed is that this process is not necessarily always and everywhere economical. Energy consumption and greenhouse gas emissions are among factors that can impugn eco-efficiency of the process in composting factories. The present study is an eco-efficiency assessment of a composting factory in Tehran calculating the real economic and ecological efficiency of cthe omposting process by considering two main external burdens: energy consumption and greenhouse gas emissions over the period 2007-11. In this research, the instruction presented by the World Business Council for Sustainable Development [1] was followed up to quantify eco-efficiency indicators. The obtained results revealed that the composting factory experienced a negative energy eco-efficiency within the periods 2007-08 (-71.97%) and 2008-09 (-69.82%). In terms of CO2 emission eco-efficiency, there were also inefficient periods in the plant in two time intervals: 2007-08 (-71.97%) and 2008-09 (-69.80%). Fortunately, this was a temporary situation so that at the ultimate year of 2011, the composting plant had an acceptable performance in terms of energy consumption (with an eco-efficiency of 166%) and CO2 emission (with an eco-efficiency of 165.85%). Overall, although the composting process is an effective strategy for better use of resources, it will sometimes impose additional burdens on the environment if the external expenditures such as energy consumption and greenhouse gas emissions are neglected or less-intentioned. [ABSTRACT FROM AUTHOR]

Although the average effective human dose from natural background radiation is about 2.4 mSv per year, the students of the Saeid Nafisi school in Ramsar received effective doses of about 250 mSv while studying there for over 5 years. The goal of this project was a retrospective study of the health status of former students of this school and their offspring. The list of the students of the Saeid Nafisi school (high background radiation) and Taleghani and Kashani schools (ordinary background radiation) was provided by the Department of Education. After matching sex, age and socioeconomic level and obtaining their consent, part 1 of the specifically designed questionnaire was filled out by interview, and clinical examinations were recorded in part 2 of the questionnaire by a physician. The data were analysed using Statistical Package for the Social Sciences 16. Our study shows that 88.1 % of general examinations of high background radiation school students were normal as compared with 85.7 % for control group. There were no significant differences. This study is interesting and unique. It reveals that there is no health emergency related to these high radiation doses. We recommend continuing the health supervision of this population in the future. [ABSTRACT FROM AUTHOR]

Objective: Sweet potato whitefly, Bemisia tabaci Gen. (B. tabaci), is one of the most important pests of various greenhouse crops in Iran. Nowadays, chemical insecticides are broadly used for control of the pests that causes risk to consumer's health. For the first time, contact toxicity of Pelargonium roseum Andrews and Artemisia sieberi Besser essential oils on B. tabaci and its possible application against the whitefly was evaluated in 2012. Materials and Methods: Essential oil with concentrations of 2500, 1250, 125, and 12 ppm were used. Infested leaves of greenhouse cucumber were treated by mentioned concentrations. After 24 hours, mortality of B. tabaci was recorded and compared after correcting by Abbot's formula. Results: Results showed that all concentrations of the essential oil could significantly reduce population of B. tabaci compared with the control treatment. Phytotoxicity of the treated leaves were recorded after 24, 48, and 72 hours and compared with the control. Concentrations of 2500, 1250, and 125 ppm caused severe phytotoxicity on greenhouse cucumber leaves and therefore are not suitable for greenhouse application. Phytotoxicity of 12 ppm was relatively low. Conclusions: This data implicated suitable protective effects of the essential oils to the pest infestation. Therefore, essential oils distillated from Geranium and Artemisia could be applied to control B. tabaci in greenhouse cucumber at V/V 12 ppm. [ABSTRACT FROM AUTHOR]