نتایج جستجو برای: irrigation and drainage network development
تعداد نتایج: 17121347 فیلتر نتایج به سال:
today water supply issue in large cities seems to be a big problem. this becomes more important with population growth and urbanization extension. to cope with this problem lots of irrigation and drainage projects have been implemented and operated that subsequently many socio- economic and cultural effects have been brought to the areas . the objective of the present study is to survey the soc...
today the image of a permanent skeletal space of cities affected by some forces or mechanisms is put in time with social-economic development and while imposes a new face and perspective to physical anatomy of cities, and prepares field to changes in content and social- economic structures of cities too. simultaneously with quitting villages in order to settle in cities by villagers, the phen...
Sand coverings account for a large part of the cost of a project. The purpose of this study is to evaluate the performance of different coatings for filtration of underground drains and reduce the cost of cornfield farms. The experiments were carried out in farm in Salman Farsi. The subsoil drainage was fitted to each test piece with a length of 120 meters, a diameter of 100 mm, and a distance ...
abstract recent studies suggest that prelistening activities play an important role in the development of listening comprehension (e.g. long 1990;chiang and dunkel 1992; schmidt-rinehart 1994; jensen and hansen 1995; robinson et al., 1995; buck, 1995; foster and skehan,1996; teng 1996; robinson, 2001; chang and read 2006). in line with previous studies and to shed light on a new aspect of sche...
this experimental study has been conducted to test the effect of oral presentation on the development of l2 learners grammar. but this oral presentation is not merely a deductive instruction of grammatical points, in this presentation two hypotheses of krashen (input and low filter hypotheses), stevicks viewpoints on grammar explanation and correction and widdowsons opinion on limited use of l1...
Irrigation water is limiting for crop production in arid and semi-arid areas. Furthermore, excess nitrogen (N) application is a source of groundwater contamination. Partial root drying irrigation (PRD) can be used as water saving technique and a controlling measure of groundwater N contamination. The objectives of this investigation were to evaluate the effect of ordinary furrow irrigation (OFI...
for several years, researchers in familiarity of efl teachers with post-method and its role in second and foreign language learners’ productions have pointed out that the opportunity to plan for a task generally develops language learners’ development (ellis, 2005). it is important to mention that the critical varies in language teaching was shown is the disappearances of the concept of method ...
controlled drainage is one of the strategies to reduce negative environmental effects in conventional drainage systems. this study examines the effect of controlled drainage on quality and quantity of drainage water, specifically amounts of salt and nitrate in drainage water, and nitrate uptake by maize (sc 704) with sandy loam soil texture in karaj. the experiment was performed as a randomized...
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