Showing 2 results for Pressure.
A. H Nasrolahi, M. Behzad, S. Bromand Nasab, M. Heydariniya,
Volume 17, Issue 66 (2-2014)
Abstract
Drip irrigation is a new method of irrigation that is rapidly growing in different countries. The emitters are the most important parts of a drip irrigation system. Many factors such as physical, chemical and biological clogging, pressure, water temperature affect the emitter´s uniformity of water emission. In this study, to investigate pressure effect on the hydraulic performance of emitters, 7 kinds of compensating emitters in the market were selected and studied in laboratory conditions. For this purpose, a drip irrigation system was designed in irrigation laboratory in faculty of water sciences engineering, Shahid Charm University, Ahwaz. Average flow of emitters, Manufacturer´s coefficient of variation of emitter(CV), emission uniformity(EU), Christiansen coefficient of uniformity(CU) and Flow Variations for all types of emitters at pressures of 5, 10, 15 and 20 meters were calculated and compared. Also, in order to compare the pressure compensating capacity, for every emitter the equation of Flow- pressure was extracted. Results showed that the D-type emitter has the best hydraulic performance from among the emitters tested. Therefore, to achieve higher efficiency and also to use it on slopes and uneven lands this emitter is recommended as the best. However, performances of other emitters are also acceptable.
M. S. Maleki, H. Byatt, T. Ebadi,
Volume 19, Issue 71 (6-2015)
Abstract
Some recent research has indicated that certain alkaline contaminations may adversely affect mechanical properties of clayey soils. To examine the potential impact of alkaline divalent barium on the swelling characteristics of KAHRIZAK clay, the major solid-waste landfill at south of Tehran, a systematic set of experiments was conducted. Observations indicated that the swelling in the studied soil that belonged to the CH-MH group with a PI of 28.44, was reduced by about 17, 37, 48 and 54 percent, and swelling pressure by about 41, 55, 65 and 67 percent, respectively, after addition of barium chloride solutions to concentrations of 0.25, 0.5, 0.75 and 1.25 molal. It was also found that addition of barium chloride solutions to concentrations of higher than 1 molal had a little effect on reduction of swelling and swelling pressure.
