Tikrit Journal of Engineering Sciences

This paper investigates the ultimate bearing capacity of a strip footing stiffened with ribs connected to its lower surface.The effect of number and depth of ribs on the bearing capacity are investigated numerically using the finite element method. Different footings resting on a clayey soil are analyzed under vertical and inclined loadings. A new efficiency factors (ER) is proposed to be added to the general bearing capacity equation in order to take the effect of ribs into consideration. The results indicate that, tire ultimate bearing capacity of a strip footing is improved via the addition of ribs.

The total solar energy intensity on the horizontal surface measured for the Kirkuk city. This is obtained by rneasuring theshort circuit current induced from standard PV module consistir-rgof 36 PV cell connected in series. The measurement performed ateach hour of daylight for a period of one year. The measured data compared with data obtained theoretically from tire empirical formulas, which indicates that the theoretical prediction of the solar energy intensity is 31% larger than the measured values. The result indicates that the Kirkuk city receives a large quantity of solar energy, because the percent of the sunshine hour to the cloud covered hour is found to be 89%. comparative cost analysis of the electricity from the PV solar cell and diesel system shows that the electricity from PV solar system at Kirkuk city is cheaper than that obtained from diesel system of about 40.6% when 15 year working period is considered.

Methyl chlorosilanes are important raw materials for the production of polyalkylsiloxanes, the basic ingredient of silicone oils and silicone rubbers. One of the main methods for the commercial production of methyl chlorosilanes, known as direct process, involves a reaction between elemental silicon (Si) and methyl chloride (MeCl). The principal product is dimethyldichlorosilane, which is used to form the polydimethylsiloranes. The aim of this work is to predict a mathematical models in which it shows the behavior of the reaction. We predict four models, these models take in consideration the reaction kinetic the physical, chemical, and design equation of fluidized bed reactor. The equations shows the conversion of MeCl as function of temperature and time, conversion of silicone as function of time, particle diameter as function of time. We have compared the result from these models with practical result from international papers. And it shows good agreement.

Alumina surface was modified by adsorption of an anionic surfactant, sodium sulfate (S.S). Typical S-shaped isotherm of surfactant on alumina was observed. The adsorption of herbicide on alumina and surfactant treated alumina has been investigated.The enhancement in adsorption of herbicide on surfactant treated alumina is observed, which may be attributed to the solubilization of herbicide on surfactant aggregates formed at solid/liquid interface. The effect of pH on adsorption has been studied. The adsorption is greatly influenced by pH of the medium. The applicability of Freundlich equation was tested for equilibrium data. The influence of various factors such as initial concentration, and mass of adsorbent on adsorption was also studied. The batch kinetics has been tested to pseudo second order reaction and rate constants were calculated.

The hydraulic characteristics of cylindrical weirs under free flow conditions were studied experimentally in order to investigate the discharge coefficient (Cd) and the influence of some significant factors and performance of weirs for discharge measuring. The experimental tests were carried out on three models of weirs in which the diameter of weir (D) was varied three times as: 8.0, 10.0 and 12.0 cm. For each model, a series of measurements were taken to measure coefficients of discharge. Results showed that the coefficient of discharge (Cd) increase with increasing the ratio of head to weir diameter (h/D),and for the same ratio (h/D), the discharge coefficient (Cd) increases with increasing weir diameter.

In this research, a finite difference method with a relaxation technique were used in a computer program which was prepared to show the influence of changing the status of sheet piles or cutoffs on the uplift pressure under a hydraulic structures.The downstream sheet pile was used inclined to the downstream side with angle of 45°, the beginning of this pile is located before the end of the structure floor with a distance equal to the depth of this pile when it is in a vertical status. With the previous situation of the downstream pile, an upstream and a middle inclined piles were used. The angle of inclination of these two piles are (14°,26°and 45°) to the ward of upstream or downstream of the structures. By comparing all cases with the standard case, the results demonstrated that the new status of downstream pile and the upstream pile inclined with angle of 14° to the downstream side gives a greater decreasing ratio of uplift pressure under the structure floor. The decreasing ratio of the above case is equal to (21.02%). When a middle pile was used in the structure, the best case, is a structure contain an inclined upstream and middle piles with angle of 14° to the downstream side and the downstream pile in the new status. This case gives a total decreasing ratio of uplift pressure equal to (22.46%).

Groundwater is considered the most important natural sources for the Mosul city, therefore the studies concentrated toward the evaluation of this resource. Data were collected from 30 wells in Mosul around Tigris river ,which includes rainfall topography and ground water levels and its fluctuation in order to compute recharges, source and the methods of its development by using sophisticated methods in data gathering and analyzing. Incurrent study the Geographic information systems (Arc View GIS) and Surfer 32 were used to estimate the quantity of ground water recharge in the Mosul city for the rainfall data for the season 2001/2002. Its found that the rainfall are the main sources of the ground water recharge in Mosul city.

The wide petroleum distillate, which has the boiling range from initial boiling point to 823 k, were hydroteated in trickle – bed reactor using cobalt – molybdenum alumina as a Catalyst. The reaction range temperatures was 598 – 673 k, while LHSV was 0.7 – 2 hr-1. The pressure and H2/Oil for all experiments keep constant at 3Mpa and 300 L/L respectively. The result shows that the sulphur and metals content decreased with the increasing of temperature and decreasing in LHSV. Desulphurization kinetic was studied and found that the kinetic of sulphur removal is of first – order. Activation energy was calculated and this value is 28.225 KJ / mole.

The research include a theoretical study of natural laminar study convection heat transfer in a vertical annuls, the surfaces were at constant temperature and the inner cylinder temperature is higher than the outer cylinder temperature. The air used as a working fluid in the annulus. Rayleigh Number was( 71 Ra 5 10 4 ) and the radius ratio were (1.7, 2.0 and 2.3). Alternating direct implicit method (ADI) was used to solve the governing equations numerically, the governing equations were transformed into vorticity-stream function formula then transformed into algebraic equations using finite difference method. The results were declared by using contour diagrams which represent streamlines and isotherms also the results were declared by velocity and temperature distribution through the annulus and local Nusselt number along the inner cylinder.It was found in this research that heat transfer by conduction in low Rayleigh Number, also increasing the thermal boundary layer around the inner cylinder as the fluid moves up while the thermal boundary layer on the outer cylinder increases as the fluid moves down.