http://dspace-su.server.ly:8080/xmlui/handle/123456789/1883 Fri, 01 May 2026 12:45:23 GMT 2026-05-01T12:45:23Z http://dspace.lslab.ly:80/bitstream/id/201cb4a3-09d7-44e3-a730-b86e84cb9b21/ http://dspace-su.server.ly:8080/xmlui/handle/123456789/1883 http://dspace-su.server.ly:8080/xmlui/handle/123456789/1987 Effect of Source and Rate of Potassium Fertilizer on Plant Growth Under Soil Water Stress Rmadan A. Milad Two pot experiments were conducted to study the effects of soil water stress, and rate and type of K-fertilizer on some growth and physiological traits of two Maize (Zea mays L.) hybrids S.C.10 and T.W.C310. Three soil water regimes (100, 75 and 50% of soil field capacity), Three K application rates (0, 50, 100 kg K/fed.) and four types of K sources (KCl, K2SO4, KNO3 and a 1:1:1 mixture of them) were applied as the treatments of a split- split experimental design for each hybrid. The total chlorophyll a and b, fresh and dry weight were measured as growth parameters and leaf area ratio, net assimilation and relative growth rates were measured as physiological parameters. The obtained data indicated significant effects for moisture stress on fresh and dry weight of both S.C.10 and T.W.C.310 maize plants in the three growth stage and total chlorophyll content only in the third growth stage for both Maize hybrids. Potassium fertilization level effects were significant on the three characters in second and third growth stages in S.C.10 and in the first and second growth stages for fresh and dry weight besides the three growth stages for total chlorophyll content in T.W.C.310. However, potassium fertilizer source effects were significant on total chlorophyll content in the third growth stage, only for both maize hybrids. Potassium source had significant effect on fresh and dry weight in the three growth stages in S.C.10 and the first and second growth stages in T.W.C.310. Generally, non-water stressed treatment (100% of field capacity), the highest potassium level (45 kg/fed.) and potassium nitrate or sulphate produced the highest values of the tested traits. Increasing K application rate was found to relief the adverse effect of soil moisture stress on the two tested maize hybrids. Also, selection of suitable K source has a beneficial effect for better plant growth. Potassium nitrate produced the highest values of the most studied growth characters. Tue, 01 Jan 2019 00:00:00 GMT http://dspace-su.server.ly:8080/xmlui/handle/123456789/1987 2019-01-01T00:00:00Z http://dspace-su.server.ly:8080/xmlui/handle/123456789/1986 CFD Modeling of Airfoil of wind turbine under different effect of operating conditions Abdalsalam Muftah Wind energy has been attracting more and more attentions due to its clean and renewable source. The aerodynamic characteristic of wind turbine airfoil directly affects the turbine efficiency. In this paper, Computational fluid dynamics (CFD) analysis of the two-dimensional air flow over a wind turbine NACA 2414 airfoil at various angles of attack and operating Reynolds number are presented. Aerodynamics airfoil performance which were represented by Lift Coefficient (Cl), Drag Coefficient (Cd) and Lift-to-Drag ratio (Cl/Cd) are determined. The geometry of the airfoil is created using NACA parametric curves in COMSOL Multiphasics Design Modeler. CFD analysis is carried out using Comsol models at various angles of attack starting from -5° to 15°, and at seven various operating condition of Reynolds number (Re = 103, 5×103, 104 , 5×104, 105, 5×105, and 106 ). Pressure and velocity distributions over finite surface areas of NACA 2414 airfoil for different angles of attack and Reynolds number are presented. Aerodynamic performance coefficients are plotted against the angle of attack. Lift to Drag Ratio at various wind speeds of (u=0.001 m/s, 1 m/s, 5 m/s, 10 m/s and 15 m/s) for the airfoil graph is plotted. The results is clearly noticed that CL/ CD is linearly increases as the value of angle of attack is increased and after a certain angle of attack it is decreased and this angle is called stalling angle. The results showed that the effect of varying Reynolds number was important on aerodynamic performance and on pressure and velocity distributions over the surface of airfoil. Tue, 01 Jan 2019 00:00:00 GMT http://dspace-su.server.ly:8080/xmlui/handle/123456789/1986 2019-01-01T00:00:00Z http://dspace-su.server.ly:8080/xmlui/handle/123456789/1983 Advantages of the Normal Derivative Method to Set Up the Integral Kernels for a Unit Disc Haniyah A M Saed We implement the boundary element method for the Helmholtz equation for a two-dimensional unit disc with Dirichlet boundary conditions. This yields boundary integral equations of Fredholm kind. Here we discuss the advantages of the normal derivative method which leads to a second-kind Fredholm integral equation instead of dealing with the resulting first-kind Fredholm integral equation. This is shown by comparing the accuracy of the boundary functions which are computed using both types of integral equations. We point out that it may be advantageous for smooth boundary to use the normal derivative method to set up the boundary integral kernels which gets rid of the weakly-singular integrals.. Tue, 01 Jan 2019 00:00:00 GMT http://dspace-su.server.ly:8080/xmlui/handle/123456789/1983 2019-01-01T00:00:00Z http://dspace-su.server.ly:8080/xmlui/handle/123456789/1981 Effect of Electric Power-Supplies on Acoustic Emission Signal during Boiling Process Tiahiret Alhashan; Tariq Aboalhol; Amal Meghrabi The dynamic bubble phenomena in two-phase, liquid/gas systems occur in many different hydraulic processes such as valves, centrifugal pumps, fluid piping transportation, boiling processes and nuclear reactors. Bubble activity phenomena cause some problems such as vibration, noise, decreased of equipment efficiency and surface pitting. Monitoring and detection of bubble activity at an early stage during the boiling process is very important to nuclear safety and many industrial processes. Acoustic emission (AE) technique in this work investigation covers the frequency between 100 kHz and 1000 kHz. Obtained results show a high feasibility of AE technology in detection and diagnosis of bubble dynamic at an early stage during pool boiling. It was observed that bubble activity is detectable with AE method, and there is a clear relationship between increasing AE signals with increase electric power-supply levels and the bubble formation during pool boiling.. Tue, 01 Jan 2019 00:00:00 GMT http://dspace-su.server.ly:8080/xmlui/handle/123456789/1981 2019-01-01T00:00:00Z