Groundwater of northern Mexico contains high concentrations geogenic fluoride (F−), a contaminant known to affect human health. The origin F− in groundwater this region has been related the weathering rhyolite and other volcanic rocks present alluvium. However, relationship concentration water depth not established. concentrations, pH, total dissolved solids (TSD) were determined for 18 wells w...

the depth control systems used in iranian tractors are mechanical and they produce variable tillage depth in uneven field surface. in this research a rotary type electronic control valve was designed and constructed. by using this valve, electro-hydraulic tillage depth control system was developed and installed on the tractor. the control system was composed of: a depth sensor, a programmable l...

pipe drain installation depth is one of the most important design parameters, which has a key role in the drained water volume and quality. in this research, the effect of pipe drain installation depth was investigated by using a physical laboratory model. drains were installed at 0.25, 0.5 and 0.85 m deep in a cubical box with dimensions of 1*0.5*1 meter filled with a sandy loam soil. nitrate,...

light is never being distributed homogeneously and it forms a gradient over biomass. the unidirectional nature of light gives rise to a vertical gradient of light intensity as a function of depth. the maximum depth of the light zone suitable for phytoplankton photosynthesis is designated as the euphotic depth. this study was designed to test the hypothesis of mixing depth of phytoplankton and i...

light is never being distributed homogeneously and it forms a gradient over biomass. the unidirectional nature of light gives rise to a vertical gradient of light intensity as a function of depth. the maximum depth of the light zone suitable for phytoplankton photosynthesis is designated as the euphotic depth. this study was designed to test the hypothesis of mixing depth of phytoplankton and i...

In the continuous gas lift operation, compressed gas is injected into the lower section of tubing through annulus. The produced liquid flow rate is a function of gas injection rate and injection depth. All the equations to determine depth of injection assumes constant density for gas based on an average temperature of surface and bottomhole that decreases the accuracy of gas lift design. Also g...