KUFA JOURNAL OF ENGINEERING

In this investigation, steady state two – dimensional laminar forced convection heat transfer of Newtonian and non-Newtonian fluids inside a duct of Rectangular shape has been studied numerically for a wide range of the Reynolds numbers of (Re.=.500 and 10000) with the Power law index (n) of Power law model ranging from (0.1 to 2), and Prandtl number of (Pr =1 and 10). Two types of boundary conditions have been considered. The first, when the side walls are heated with different uniform temperatures and the horizontal walls are insulated. The second, when the bottom wall is heated by applying a uniform heat flux while the other walls at the constant cold temperature. Also, the time independent non-Newtonian fluids under consideration were assumed obey to the Power law model. The numerical results of the values of average Nusselt number have been confirmed by comparing it to similar known previous works using the same boundary conditions. Good agreement was obtained. The results are presented in terms of isotherms and streamlines to show the behavior of the fluid flow and temperature. In addition, some graphs that repesent the relation between average Nusselt number and the parameters mentioned previously are drawn. Also, the results show that the power law index (n) has, for a given Reynolds and Prandtl numbers, a large effect on the heat transfer rate at high Reynolds number. Twelve different correlations to show the dependence of the average Nusselt number on the power law index, the Reynolds and Prandtl numbers has been fund.

An analytical solution for determining the elastic critical buckling load for tapered members including shear effect are studied in this paper with different support conditions. The calculations are based on the exact stability function including shear effect for uniformly tapered beam-column having laced or battened build-up structural members, and approximate stability functions for a wide range of non-prismatic member including shear effect using the finite difference method. The modified stability functions for nonlinear tapered member including shear effect is also obtained in this paper by using the stability functions for a linearly tapered member in the form of modified shape factor ( ) and modified taper ratio (ū). Buckling of tapered columns is studied in many numerical examples. The results show that, inclusion the effect of shear deformation in the calculation of critical load can result in a significant reduction in the value of the critical load for both prismatic and non-prismatic laced columns. The effect of the shear is depending on the value of shear parameter µ2 and tapering ratio u. The average ratio of reduction is (63.315%) and (64.7 to 65) % for prismatic and non-prismatic laced columns respectively. In the structures having prismatic and non-prismatic solid columns, the effect of shear deformation can have a significant effect with the range of (32.42 to 56.78) % on the value of critical load.

The development process of oil and gas fields is one of the most important technical and engineering challenges facing the oil companies operating in all areas of the oil sector during the production life of these fields, because of the variables and complexities associated with the development embodied in the analysis process of decision-making rational choices in the development stage of producing oil fields. In this research approved the application of risk analysis as a decision-making in the implementation of the development project of the oilfield under study, which is located in southern Iraq, as well as determine the effect of inaccuracy of some variables in this analysis, which was quantified in two parts, the first of which was related to risk analysis in the event of current situation of the field in terms of productivity, while the second one related to the proposed development method, where it underwent the cases mentioned in this part of the risk analysis, except in cases where production runs up to the water cut in producing wells up to 80% were excluded from the analysis. Results of this analysis for both parts were compared with the amount of accumulated production that were calculated previously for the same cases mentioned in previously Part II, which provided under the developmental study of the mentioned field in 2007 for one of the produced formation in the primary reservoir of the field. The comparison results reflect the importance and eligibility implications of the used tools as promising and supported in their decision-making in right way of engineering studies submitted for the development of oil fields. As well as the results indicate the importance of adopting risk analysis is a good guide to evaluate the methodology and scalability performance of oil fields and the completion of operations associated with them.

Rutting is often responsible for premature maintenance and rehabilitation activities reducing service life of the pavement. Several finite element computer programs for analyzing flexible pavements have been developed over the years. Most of these programs (like ANSYS)did not take into consideration the effect of the aging factor on the behavior of viscoelastic asphalt concrete layer. The present work uses a displacement based finite element method to compute vertical compression strain and rutting depth for a flexible pavement system of three layers taking into consideration the aging (temperature) effect depending on Williams, Landel and Ferry (WLF) equation. Two popular tire/axle configurations with different tire pressure are investigated using the traditional approximate circular tire print. The results showed that the difference between the proposed technique and some other methods neglecting aging effect ranges from 5% to 15% while the difference between the proposed technique and linear elastic Pro-Engineer (version 4) program ranges from 10% to 17%.

The focus of this investigation is to study the effect of the two dimensional isotropic surface roughness of both , journal and bearing on the maximum eccentricity ratio and the load carrying capacity of the finite length plain journal bearing , on the basis of full film lubrication regime to reduce the wear and heat produced by friction to extend the machine element life , in the steady state operation conditions. The appropriate equation to predict the suitable minimum film thickness which include the surface roughness is used . The Conventional Reynolds equation in two dimensional forms are solved numerically . The change of viscosity due to temperature and pressure , using adiabatic solution ,were taken into account. To investigate the effect of surface roughness on the maximum eccentricity ratio value and load capacity , it was assumed that there are two surfaces smooth and rough and are compared with each other . The results of this work show that the increase of the surface roughness case the maximum eccentricity ratio decreases at L / D ratios of 0.5 , 1 at range of roughness 0.3 – 1.2 Mm , which means that the limit of bearing to work with a steady state , full film lubrication . The load ratio at L / D = 0.5 is greater than at L / D = 1 for clearance ratio 0.001 , 0.002 . The surface roughness have no influence on the bearings that have 90 mm diameter or larger at clearance ratio 0.002 .

High impact polystyrene (HIPS) was subjected to repeated thermal and shear stresses by different methods, using a high pressure capillary Rheometer, a laboratory extruder and a Brabender plasticorder. The results showed that the recycling of HIPS caused a decrease in the shear stresses and consequently in the viscosity at constant shear rate. The high pressure capillary Rheometer gave a greater decrease than with the Brabender plasticorder. Tensile strength values were progressively decreased with the laboratory extruder, but increased in the case of Brabender mixer; the elongation was decreased in both cases. This work was then applied in a local plant to compare experimental and actual results.