In order to study MIG welding process of aluminum alloy with longitudinal magnetic field, thermal efficiency with longitudinal magnetic field was analyzed, as well as softening behavior of heat-affected zone (HAZ) and base metal were investigated. The results showed that under the action of longitudinal magnetic field, welding current decreased and resultingly total heat input reduced as the ex...

abstract in this research, temporal trends of reference evapotranspiration (et0) values were investigated in arid regions of iran. for this purpose, the meteorological observations collected from 11 high quality meteorological sites for a 41-year period (1965-2005) were used and statistically significant et0 trends in the monthly, seasonal and annual time basis were detected by the non-parametr...

within the climate change debate and its probable impacts on water resources systems, design and operation of management plans based on the assumption of stationary hydrology may cause serious challenge to accurately predict future supplies. therefore this case study is trying to assess trend in hydroclimatic variables of karkheh rivers upstream by applying modified mann-kendall trend test on l...

 Background: Smoking within students community of the medical sciences can negatively impact the attitudes of the society in future. The objectives of this study were to assess the prevalence and trends of smoking among students of Tehran University of Medical Sciences. Method: This study was conducted in four consecutive years from 2006 to 2009. The study sample was taken from the first- to fo...

The initial adhesion, spreading and cytoskeleton changes of fibroblast NIH3T3 cells onto hydroxyapatite (HAp) and oxidized poly(styrene) (PSox) sensors preadsorbed fetal bovine serum were analyzed by using a quartz crystal microbalance with dissipation technique and an atomic force microscopy (AFM). The frequency shift (Δf ) and the dissipation shift (ΔD) curves on HAp nanocrystals showed the d...

utilizing the gathered failure data and failure interval data from tabas coal mine in two years, this paper discusses the reliability of powered supports. the data sets were investigated using statistical procedures and in two levels: the existence of trend and serial correlation. the results show that the powered supports follow the gamma reliability function. the reliability of the machine de...

evapotranspiration is one of the most important components of the hydrological cycle which is directly influenced by atmospheric conditions. this study investigated annual and seasonal trends in reference evapotranspiration (et0) and its key influencing climatic variables during 1966-2005 at 10 stations in southern iran (with centrality of fars province). first, multivariate regression analysis...

An understanding of the relative impacts of the changes in climate variables on crop yield can help develop effective adaptation strategies to cope with climate change. This study was conducted to investigate the effects of the interannual variability and trends in temperature, solar radiation and precipitation during 1961–2003 on wheat and maize yields in a double cropping system at Beijing an...