Tikrit Journal of Engineering Sciences

In this research, Mindlin’s thick plate theory is extended to include orthotropic plates under the effects of externally distributed moments and shearing forces at top and bottom faces of the plate. These shearing forces produce in-plane forces in plates and the extensional effects of these in-plane forces are considered. The transverse sections of the plates have five degrees of freedom. These are the transverse deflection, the two independent rotations of the normal to the middle plane and the two mutually perpendicular membrane displacements. Thus, five expressions of the governing equations for thick orthotropic plates are obtained with the inclusion of the effects of externally distributed moments and applied shearing forces. As an application to the generation of distributed moments and shearing forces, the problems of thick orthotropic plates resting on elastic foundations with both compressional and frictional restraints are investigated. The finite-difference method was used to solve the governing equations. Besides, finite elements are formulated and used. Good agreements are found in the results from both methods of solution.

This research aimed to emphasis Tigris river water quality and quantity variations at two sites: Qaber Al-Abid village downstream Mosul city and Dwezat village after its meeting with the Upper Zab river using factor analysis technique. Weekly samples were collected from the two sites along a year. Samples were tested for pH, electrical conductivity, total alkalinity, total hardness, calcium, magnesium, sodium, potassium, chloride, sulphate, nitrate, phosphate, dissolved oxygen, biochemical oxygen demand, suspended solids, total solids, total dissolved solids, in addition to the discharge of the river. The results of each site were analyzed statistically using factor analysis for each season and for the whole year. Factor analysis concentrated the measured water quality parameters and discharge into two to four factors for seasonal analysis, which represent (90.69%-100%) of the variation in water quality and quantity. On the other hand, five factors were extracted from the yearly data at Qaber Al-Abid site and six factors at Dwezat site.The results of factor analysis revealed that pH, conductivity and PO4- 3 is the highest contributor to the variation in water quality at the two sites. Organic pollution came in the second order in Qaber Al-Abid since it is location downstream of Mosul city, while the effect of Upper Zab made the discharge and sediment load (SS, TS and TDS) in the second order for the variation in Dwezat site.

The need for higher production rates and lower production cost emphasized the need to increase the rate of metal removal on metal cutting machine tools. This is however, limited by the different technical and technological constraints of the machining process so that the problem has to be handled as an optimization to determining the optimum values of the machining parameters. Several optimization techniques have been developed to solve this problem such as linear and non linear programming methods. However, due to the complexity of the mathematical models and the relatively large number of constraints involved, there is no obvious solution. This paper introduces a developed algorithm and compared to one of the well known iteration method that is the Sequential Unconstrained Minimization Technique (SUMT). The comparison through an example problem shows that the developed algorithm is more efficient, accurate, as well as quicker the optimum solution.

The work described in this research is concerned mainly with the experimental verification of the effect of boundary layer suction on the diffuser performance having three different divergence angles. The test facility has been designed so as to permit different values of suction velocities (0, 0.386, 4.88 and 6.365 m/sec). The static pressure and total pressure were measured by pitot – static tube and inclined manometer. The application of boundary layer suction was found to increase the pressure recovery and hence increase the diffusion efficiency. An improvement in pressure recovery was found to be more significant for diffuser having divergence angle (15o).The maximum percentage improvement in pressure recovery obtained is (34.7 %). The study of B.L control through its suction leads to better understanding of the flow geometrical design and parameters.

The mathematical modeling of plate heat exchanger was studied by introducing rectangular pulse change in inlet cold water flow rate and measuring the temperature of outlet cold water. A theoretical model for the plate heat exchanger was developed based on the heat balance and used the frequency response analysis techniques to determine the best model parameters. The results show that the dynamic behavior of plate heat exchanger can be approximated by a time delay with first order system and a closed fit between the theoretical coefficients of the system and these data by using frequency response method.

A morphological variations occurs in the paths of rivers due to many reasons such as the hydraulic changes in the natural flow regime of rivers in-addition to the human activities on rivers such as dams constructions on rivers. Many morphological variations created on Tigris river reach within Mosul city, north Iraq for different periods between 1956 to 2002 had been studied such as the changes on the river width specially near the bridges sites and also the development of the dimensions of the islands and bars within the river reach. The available topographic maps and also an aerial photographs were depended during the data analysis with some field reconnaissance . The research work concluded that one of the main reasons for the development of the islands is the flow regime variation of Tigris river as a result of the Mosul dam operation which in-turn leaded to a reduction in the transported sediment load in the reach due to the released high stream power clear water discharges of sediment from Mosul dam. The second reason was the reduction in the water level which in-turn change the middle and side islands in the river with the growing vegetation cover such as trees and weeds specially in the sites downstream the meander of Al-Rashidia Village and downstream Al-Shuhadaa bridge and upstream Ninevah bridge and finally upstream the fourth bridge in Mosul city.

The objective of this work is to study the effect of impact and blast dynamic loading upon concrete plates reinforced with normal deformed steel bars as well as steel or glass fibers. In order to examine the effect of using different volume and weight fractions of s skeletal bars and steel or glass fiber reinforcements on the impact and blast resistance, 24 plates and 24 prisms were manufactured as test specimens. A set consisting 0f 8 plates were tested under high velocity impact using 14.7 caliber bullets with a shooting distance of 63 m. The specimens with 1.5 % steel fiber and two layers of steel mesh (8 mm at 75 mm) have shown resistance to full perforation of the bullet. Improvements to the resistance to spalling, scabbing and crack growth have also been observed. Field blast testing was carried out on a second set of 8 specimens by using a charge of 100 gm located at the center of each specimen. All the plates were 160 mm thick and with had minimum reinforced of 0.75% glass fiber and a single layer of steel mesh (8 mm at 75 mm). Have shown resistance to full perforation of waves and have restricted the number, the width and the growth of cracks. The last set of the remaining 8 plates was subjected to a low speed impact test performed by a falling steel ball. Test results clearly show the significant effect of using steel and glass fiber besides deformed bars to enhance the impact resistance by 400 % and 20 % by using 1.5 % steel fiber and 0.75 % glass fiber resistance .Energy absorption capacity and ductility were also increased by 100 % and 600 % by using 1.5 steel fiber. Chang in compressive strength of about ±6 % and ± (20 – 30 ) % were observed by using 1.5% steel fibers and 0.75% glass fibers respectively. The inclusion of 1.5% steel fibers and 0.75% glass fibers together with deformed steel bars have improved the tensile strength by 200% and 70% respectively.

A study of some of quality characteristics for the precipitation in several sites of Samarra and Balad in Iraq was achieved .The period of the study was from 7-January to 15-February /2006 which is commonly recognized with annual rains during the winter.. The wind velocity ,temperature ,and humidity during the samples collection period ranged (2-8)m/s ,(6.5-18)0C, and (51%- 97%) respectively .Chemical tests included the concentration of sulphates(SO4) ,nitrates(NO3),calcium (Ca), and pH. Also the tests investigated the possibility existence of some heavy metals which were iron (Fe),lead (Pb).and nickel(Ni). SO4 concentrations range was (100-250)mg/l while NO3 concentrations range was (60-196)mg/l. The tests proved inexistence of calcium, lead, and nickel while the Iron concentration range was (0.3-6.8)mg/l. The pH range in the samples was(5.56-6.7),Thus the rain in all sites was considered as acid rain.

In this research, an empirical study has been done to find fouling factor for water flowing inside air-cooled plate finned radiator with constant heat flux beside the boundary condition of the thermal process. The research also required practical tests for finite period time(twenty days for each test). Two kinds of treated water that used in cooling towers was used to show the agreement between calculated fouling factor and this treatment. The work required test specific radiator in the beginning to calculate a design fouling factor that compared with others results with keeping the operation conditions constant. A simulation computer program required to enters all the boundary conditions for the heat system besides the correlating equations for the heat transfer of the radiator. The results show a good inspection for the fouling factor that agrees the practical analysis for the water treatment.

The project of this work is to control the temperature of mixture which enters to the I.C.E. and keeping it within a certain range which enhance its performance. Four stroke, Engine working with benzene as a fuel was used. Experimental data were taken included the exhaust temperature and the flow rate of both air and fuel. These data were formulated by using suitable theoretical relations for heat exchanger. The dimensions of the exchanger were assumed to control the inlet mixture temperature. The results proved that, it is possible to control the entering mixture temperature which enters to the I.C.E. by controlling to the speed of rotary exchanger. The results were that, at the temperatures of the environment 5oC and 10 oC it was prove that the RPM of the exchanger should be 10 RPM, also at the environment temperatures 20,30, and 40 oC ,the rotation speed should be within the ranges (3-10),(2-5.5) and (1-2) RPM respectively. In order to guarantee staying the entering mixture temperature within, the required range.