Sediment Entry Investigation at the 30 Degree Water Intake Installed at a Trapezoidal Channel
2 Abstract: A major problem which most of lateral intakes are faced with is sedimentation and sediment delivery. This process causes many problems such as reduction flow discharge capacity in irrigation canals as well as threatening of blockage of water during low water flow. Therefore it is the main goal of engineer to design an intake with higher flow discharge and low sediment delivery. Since most of lateral intakes are installed at trapezoidal which has not received the same attention as intake from rectangular canals, it is the main goal of this study to investigate sediment delivery to an intake from trapezoidal canal. In this study, sediment tests carried out for different hydraulic conditions at a 30 degree water intake installed at main channel with inclined bank. From analysis of these it was found that the flow patterns at the upstream of the intake has been modified in such a way that more water from surface layers are diverted. Therefore less suspended sediment enters the intake. Also it was found that in all tests the amount of sediment enters the intake reaches its minimum value at Froude Number between o.35 to o.4. In low flow depth because of the effect of bed roughness over strength of secondary current, the suspended sediment enters the intake is lower compare to the higher flow depth for the same conditions.
Effect Of OffTake Angles On Spatial Distribution Of Silt Materials At Concave Channel Bifurcation
A meandering physical channel was constructed and used to investigate the effect of off-take angles on suspended sediment distribution at concave channel bifurcation. Four different off-take angles of 30 0 , 45 0 , 60 0 and 90 0 with varied main channel flow rates Q16, Q17 , Q18, and Q19 were used for the study. Predicting statistical equations dependent on the off-take angles and main channel discharges for the evaluation of the tributary channel sediment intake were developed. Results of the studies showed that even with constant main channel discharge, the tributary channel sediment intake increased significantly with higher off-take angles. It was observed that the predicting equation under estimated the tributary channel sediment yield for off-take angles between 30 o – 70 o and for those between 70 o 90 o the sediment values were over estimated for all the main channel flow rates considered. The predicting tributary sediment values equaled the experimental values at the off-take angles of 50 o – 70 o but varied differently for each of the main channel flow rates. It could be seen from the various off-take angles considered that the divergence in results obtained from the experimental works and predicting equation is in the range of 2.9% 17.8% for minimum main channel flow rate and 12% 36% for maximum main channel flow rate suggesting that the predicting equation could be useful in the evaluation of sediment yield at concave channel
Simplified impedance design and control for low-cost high-speed channels
Impedance design is the fundamentals of signal integrity at the very beginning, but controlled impedance is always costly or time-consuming for the high-speed channels. In this paper, many simulations of channel parasitics were taken and calculated that met with the specified impedances and correlated to the measurements very well. Selection of the different substrate stack-up without any layout modification in the BGA package reversed from the failed verification to pass the differential return loss. Adjustment of lead widths and spaces in the limited room of leadframe package improved 6 Ω of differential-mode impedance compared to the conventional leadframe packages. The differential pairs with wider traces routed on the 2-layer PCB are more robust for over-etching effects whose impedance errors are less than 5% without special impedance control. Moreover, those pairs inserted with a thin ground trace achieved 90 Ω differential-mode impedance and 28.2 Ω common-mode impedance simultaneously with 35% less routing area for MHL application and reserved a 10 Ω series resistor for ESD protection. With those diligent designs, the leadframe package and the 2-layer PCB can be still adopting in the consumer electronics for high-speed applications.