Time of concentration, Tc, is defined as time elapsed from the beginning of rainfall infiltrated into soil layer until it reaches a constant infiltration rate (fc) which is indicated an equilibrium subsurface flow rate. In hydrological view, time of concentration plays a significant role in elaboration of transformation of rainfall into runoff in a watershed. The aims of this research are to define influence of soil density and soil water content in determining time of concentration using infiltration concept based on water balance theory, and to find out the effect of land slope this time. Watershed laboratory experiment using rainfall simulator was employed to examine time of concentration associated with infiltration process under different slope, soil density and soil water content based on water balance concept. The steady rainfall intensity was simulated using sprinklers which produced 2 dm3∙min–1. Rainfall, runoff and infiltration analysis were carried out at laboratory experiment on soil media with varied of soil density (d) and soil water content (w), where variation of land slopes (s) were designed in three land slopes 2, 3 and 4%. The results show that relationship between soil density and land slope to time of concentra-tion showed a quadratic positive relationship where the higher the soil density address to the longer time of concentration. Moreover, time of concentration had an inverse relationship with soil water content and land slope that means time of con-centration decreased when the soil water content increased.
While the Slope Fault Model method can solve the soft-fault diagnosis problem in linear analog circuit effectively, the challenging tolerance problem is still unsolved. In this paper, a proposed Normal Quotient Distribution approach was combined with the Slope Fault Model to handle the tolerances problem in soft-fault diagnosis for analog circuit. Firstly, the principle of the Slope Fault Model is presented, and the huge computation of traditional Slope Fault Characteristic set was reduced greatly by the elimination of superfluous features. Several typical tolerance handling methods on the ground of the Slope Fault Model were compared. Then, the approximating distribution function of the Slope Fault Characteristic was deduced and sufficient conditions were given to improve the approximation accuracy. The monotonous and continuous mapping between Normal Quotient Distribution and standard normal distribution was proved. Thus the estimation formulas about the ranges of the Slope Fault Characteristic were deduced. After that, a new test-nodes selection algorithm based on the reduced Slope Fault Characteristic ranges set was designed. Finally, two numerical experiments were done to illustrate the proposed approach and demonstrate its effectiveness.
In this paper, finite element modelling is employed for simulating and analysing seepage and slope stability of earthfill dam via GeoStudio software. Two products are employed, which are SLOPE/W for slope stability and SEEP/W for seepage analysis. The behaviour of earthfill dam with four different types of sandy soils having different values of hydraulic conductivity (K) has been studied. Different upstream (US) slopes of 1:2, 1:2.5, 1:3 and 1:3.5 for the earthfill dam are simulated. The downstream (DS) slope is constant at 1:2. The results showed for all the four types of soils that when the US slope is increased, the amount of seepage from the dam increases and the factor of safety (F) decreases. For each US slope, when K (type of soil) increases, both seepage and F increase. Fine sand soil is associated with less seepage and less F. Sixteen equations are obtained to predict both seepage and F with respect to US slope for each type of soil and K of the soil for US slope. An experimental model for earthfill dam is constructed in the laboratory of hydraulics, Benha University to investigate the seepage of water through earthfill dams. It is concluded that seepage decreased when K decreased, and when the US slope for each type of soil decreased. The seepage increased when K increased for each US slope. Seven equations are obtained to predict seepage with respect to US slope for each type of soil, and K for each US slope.
A computer model EUSS (Emission Uniformity on Sloping Surfaces) has been developed to design and evaluate the system capacity under operating conditions for drip irrigation system. And achieve the desired value of emission uniformity that is not significantly different according to the recommended values by applying it in field experiment located at Al- -Slahia city, Egypt. The model has the ability to design the system by all of the common design techniques and have ability to customize any of them.
EUSS model includes two main parts: crop water requirements, and hydraulic calculations of the system using metric unit system. It developed in graphical user interface of the programming language C-sharp (C#) by using Microsoft Visual Studio. The model database is containing the equations, tables and reference values to get more rapid and accurate results, and gives the opportunity for selecting some parameters such as: soil properties, characteristics of the corresponding crop, and climatic data. EUSS model allows the user to assume or set definite values, for example plot layout, land slopes and topography, the emitter characteristics and operating conditions.