Tikrit Journal of Engineering Sciences

This study used the definitions of irrigation systems evaluation parameters: application efficiency; application adequacy and application uniformity, in addition to the storage efficiency, the deficit coefficient and deep percolation losses. It was adopted the linear distribution of the infiltration depths for cases that intersects the line of the distribution infiltration depths with the depth required in the root zone. It was determined a several equations for the expression of each of the storage efficiency and deficit coefficient first: as a function of both the application adequacy and application uniformity second: as function of both the application adequacy and application efficiency third: as function of both the application adequacy and deep percolation losses. These equations lead to ease of use and recruitment of these transactions, both in the evaluation of irrigation systems or follow-up infiltration depths within the root zone leaching of a particular crop during the growing season to find a function of productivity.

In this research a theoretical & experimental study was conducted on mixed convection heat transfer of flow through sector filled by porous media heated with an axial uniform heat flux on the side walls and thermally insulated from upper & lower surfaces. The theoretical study includes the derivation of governing equations for the flow & heat transfer through the porous media. These equations were reduced to dimensionless momentum and energy equations in which variables were (temperature, stream function and the ratio of Rayleigh to peclet numbers). These equations were solved numerically by using finite difference method & marching process. Numerical results represented by a stream function counters & isotherms for different values of Rayleigh & peclet numbers .The results shown that the radius stream circle increase & isotherms line increase far from walls when rayleigh number increased. The experimental side included study for temperature distribution & local nusselt number along thelength channel in the domain of peclet number between (53.1- 537.4) & rayleigh number between (3.4 – 299.9). The result showed that the temperature increase along the fully develop region and the decrease at the end of the channel. so the local nusselt numbers decreased and then became stable through fully developed region and the porous media has more influence on heat transfer which increase by increase in Rayleigh & peclet numbers. Also found that there is good agreement between theoretical and experimental result so the highest percentage of deviation is (10%).

Many new studies suggest into the possibility of obtaining positive results when exposing the water to the magnetic field of the particular iceberg, where this lead to change some properties of the water, and that the main objective for the design of systems of drip irrigation is to reduce the losses water that occur as a result of deep penetration or surface runoff. The objective of this research is to study the effect of treatment magnetism on the movement of water and the distribution of moisture in the soil, where this study included a 17 tests using three rates of addition of water (1.8, 2.4, 3.0) cm3/min/cm and four intensities of magnetic water treatment (500, 1000, 1500, 2000), in addition to the use of normal salty water and salty water treated magnetically. The results show that the wetting front of water treated magnetically, whether sweet or salty, progressing faster through the soil than the wetting front of normal water (without treatment) at all adding rates of water, where the increasing percent in the size of the wetted area of soil when using the magnetically treated water with intensity of 2000 gauss is 12 % and 18 % and 15.3 % for adding rates 1.8 and 2.4 and 3.0 cm3/min /cm , respectively, also, the moisture content of the soil as well as the proliferation and homogeneity was higher in the case of the using magnetically treated water.

The effect of polypropylene fibers, steel fibers and hybrid polypropylene - steel fibers which consist of (50% polypropylene fiber+50% steel fiber), with various volume fractions 0.25%, 0.75% and 1.25% on the flexural behavior of Reinforced concrete T-beams under static load was investigated in this research.
To carry out this research ten concrete mixes were prepared one for reference high strength concrete (without fiber), and the other contain all types and volume fractions of fibers. For eachmix three reinforced concrete T-beams, three cubes (150×150×150mm) and three cylinders (150×300mm) were casted. Water cement ratio was constant 0.38, silica fume with ratio of 10% as a partial replacement by weight of cement and super plasticizer with ratio of 3% by weight of the cementitious material were add to enhance the bond between fiber and cement matrix.
28-day compressive strength and split tensile strength tests were made on hardened concrete specimen. The result showed that polypropylene fiber had little effect on mechanical properties of the high strength concrete. Compressive strength and splitting tensile strength of the steel fiber-reinforced concrete improved with increasing the volume fraction, achieving 24.5%, 43%, respectively, at 1.25% volume fraction. On the other hand, the addition of Hybrid fiber to high strength concrete improved compressive strength and splitting tensile stress with slight decrease as compared with the best improvement.
All of the reinforced concrete T-beams were tested in flexure using controlled displacement two point loads applied on simply supported T-beams, during this test the load and deflection at mid span were measured. The result shows that the addition of polypropylene fiber had a little effect on the behavior of reinforced concrete T-beam at first steps of loading until yielding load, while, it was more effective in improving ductility and toughness (energy absorption) where the ultimate load and max deflection were increased with increasing volume fraction. The addition of steel fiber increased the cracking load, yield load and ultimate load capacity with increasing volume fraction, at the same time reduce deflection. The ductility improved by the addition of steel fiber, but this improvement decreased with increasing the volume fraction. The addition of hybrid fiber improved crack load, yield load, ultimate load, ductility and toughness at all steps of loading.

This research is devoted to investigate the effect of shot penning time by steel ball with diameter 1.5 mm on the wear resistance of (Al-3.5%Cu) alloy. A pin –on- disc technique has been used to evaluate wear rate of the specimens as prepared and the specimens which treated by shot peening at various time (10,15, 25, 35) min ,were slide under dry sliding conditions on the carbon steel disc at various applied loads (9.81, 19.62, 29.43, 39.24 and 45)N and slide periods(30, 60,90 , 120 and 150)min under variable sliding speeds(0.94, 1.88, 2.82, 3.76 and 4.9) m/s.The result show that the wear for all the shot peen times have improved the wear resistance and best resistance has been achieved at time 25 min.

Transient stability analysis is considered one of the most important subject related to any power system, where the study aim is to estimate whether the system will stay stable in the event of abnormal cases. Fuzzy Logic is used to estimate the value of added braking resistance required to bring the system to its normal state. This method has been applied with experimental system having five buses.

In this thesis the dynamic characteristics (natural frequency and mode shape) of cantilever plates was studied when they immersed partially or totally in the fluid. The viscosity, density and compressibility of the fluid were taken into account in the theoretical analysis by using the (ANSYS Package) which mainly depends on the (Finite Element Method) in the analysis; by execute interaction between fluid and plate in the interface surface. The (damping analysis) method was used to analyze the new fluid-plate system; this new system is different in its characteristics when compared with the characteristics of the fluid or plate individually. The results were compared with the dry plate characteristics, which were obtained by using the same analyses package, but in this case the (modal analyses) method was used.
The natural frequencies and mode shapes for cantilever plates with different aspect ratios immersed in different ratios in fluid were obtained. The effects of submerging ratio and aspect ratio on the plate's dynamic characteristics theoretically and experimentally were investigated. The results showed that, the submerged of cantilever plate in fluid reduce the natural frequency, and this depends on the fluid type, submerged ratio and aspect ratio, and the density is the most influential fluid property on the dynamic characteristics of the plate.

The present work is devoted by an experimental study for an important parameters to increasing the thermal and internal efficiency for a steam power plant by reducing the condenser pressure, but there is a problem in condenser performance which is, air inter to inside condenser prevents it to continue with the same production. The experimental work was conducted using the steam power plant (Didacta- Italia) made in the university of Damascus/ syria .This study aim to (1) Reducing the condenser pressure to increase the thermal efficiency, (2)The condenser efficiency must be constant with time by suction of air collection inside the condenser to make the quantities of air (inside and outside) is equal. By Reducing the condenser operating pressure to (0.45 bar, 0.40 bar, 0.35 bar, 0.30 bar, 0.25bar) with all the other parameters are constant. A computer program (Fortran 90) was used . After the measurements and calculations for each state of reduced condenser pressure were given , the thermal efficiency increased by ratio 4.3% and the internal efficiency increased by ratio 2.1 % when the condenser pressure reduced to 0.25bar. Also, the max. efficiency of condenser was 80.09 % with constant production by the continuo of air suction .The results are represented graphical and discussed. The inclusions dependent on the results of this study.

Aluminum A319 Alloy under applied pressure ( 10 , 15 , 20 , 25 , 30 ) MPa, and pouring temperature at 850
were produced, while the pre-heating die temperature at 300
.
Effect of both fast isothermal and solution (T6) heat treatments were studied, on A319 alloy, which includes: Hardness, Density and Microstructure. Results show an important role of these treatments especially isothermal on the microstructure and morphological phases, as well as, improve the mechanical properties of the alloy, by the increasing of both hardness and density.

Theoretical and experimental study of die angle, and extrusion speed effect on relative extrusion pressure of annealed AA6061 aluminum alloy have been carried out in this research. Two theoretical fields have been employed, rigid-plastic field and mixed field, to predict the relative extrusion pressure. A FORTRAN program has been developed to calculate the relative extrusion pressure and its compounds. The tests have been conducted with various, die angle (30°,60°,90°,120°,150°) and various extrusion speed (10,7,3) mm/min.
The results showed an increase in shear power and friction power with increasing die angle, while no effect was observed on the internal power of deformation. It was also found that the relative extrusion pressure, the inhomogeneous strain, and the shear strain across the section increase as the die angle and extrusion speed increase. Experimental tests showed that the optimum die angle was 60° while the optimum die angle was between 35°-90° and 46° according to the mixed field and the rigid- plastic field respectively.

The present study carried out to use the water harvesting techniques to collect the water behind the dams proposed in the west southern desert from Iraq and then use this water for generating power to illuminate remote villages situated in the studying region .The study shows that there is feasibility to generate about 455kw to illuminate 337 houses at the rate of 1350watt per house and by request human consumption for 440914 persons at the rate of 450 liter per person per day. Also there is a feasibility to establish micro hydropower generation contains number of turbines designed to generate power variety from 2.5 to 25 kw.

In this paper a good mathematical model for three phase induction motor using their electrical and mechanical equations which describe its operation and performance. The modern computational technique (Matlab/Simulink) has been used to study transient conditions of the motor. The behavior of the motor observed according to their speed, torque, stator current and rotor current by subjecting the motor to different conditions like, starting, sudden load, one phase disconnected, sudden increasing or decreasing the motor voltage and lightning effect. The model is used to investigate the effects of variation in the machine size on the dynamic performance, to select the appropriate motor for specific application. The simulation results show the activity of the modern technique in predicting the behavior of an induction motor under different operating conditions.