DIYALA JOURNAL OF ENGINEERING SCIENCES

In cold lubricated tube extrusion of ellipse section the material properties and surface quality of the extruded products are influenced by the die profile so in the present analysis the axial velocity component on the intermediate cross-section in the plastically deforming region is expressed as a general function of the coordinates. This allows the description of complete three-dimensional distortion of flow rendering more realistic flow patterns. From the derived kinematically admissible velocity field, corresponding upper-pound theory the extrusion pressure is then obtained by optimizing the pressure with respect to the given parameters. The effective strains are computed in order to study the work hardening pattern of the extruded products ,also (F.E M) by ANSYS (11) software was used in building, loading and solving the extrusion process, the model generation depends on the Billet (AL 2024 fully annealed) have been carried as the working material. In the computation the product shape was ellipse with the effects of area reduction, die length product shape complexity and frictional condition on the extrusion pressure, the metal flow and distribution of the final effective strain have been studied extensively. The simulation using (ANSYS 11 PROGRAM), theoretical predictions both in extrusion load and metal flow are in good agreement with the experimental results.

Microstrip antenna has many applications nowadays. The rectangular microstrip antenna is one of the microstrip antenna types, it can be designed using many softwares. In this paper, a new method was suggested to do the simulation; by integrating Matlab in Visual Basic. Due to the good development of the personal computers, the simulations methods were activated and used widely. No software has the visual window that meets some of our requirements. It is well known that the visual basic is not completely a scientific language, thus, by adding to it a strong scientific ability, it will be very powerful language. This step was done successfully and the rectangular microstrip antenna was simulated in this way.

The rehabilitation of cracked pavement by overlaying, without any improvement, is rarely a durable solution, as the cracks rapidly propagate through the new asphalt layer. Cracks reflection through the road structure is one of the main causes of premature pavement deterioration which shortens the service life of overlays. The prime objective of this research is find the suitable remedies for this problem, by optimizing overlay asphalt mix design after considering the properties of various available material types, amounts and exposure conditions, Which include: two grades and five contents of asphalt cement, two aggregate maximum sizes and one type with different contents of asphalt modifier additives with reclaim tire rubber. A total of 160 Marshall Specimens were prepared and tested by Marshall, Indirect tensile and Creep tests at different temperature. To simulate the overlay performance under a rolling tire, 18 compacted asphalt concrete beam samples are tested using a modified wheel tracking apparatus. It can be concluded that mixes with optimum content of asphalt cement grade (40-50), 12.5 mm aggregate maximum size and 3% of reclaim tire rubber (by wt. of asphalt) give the maximum resistance to reflection cracking.

Light truck is considerably crucial for all the world economic growth since it was used in transportation for various kinds of commodities. Leaf spring is the most admire alternative utilized in the suspension system of this specific truck due to their low production cost, reliability and maintainability. In this, study a rational technique to design leaf spring for light truck is investigated. Simulation resembles to constrained condition when mounting on the vehicles were undertaken to examine the stresses distribution for each leaf. In this research the leaf spring is used on light truck with following information: Number of leaves equal five, Thickness of each leaf equal 10mm, length of distance from vertical line that divides the leaf spring to two equal parts, to one end of side of leaf spring, varies from (500 to 1000) mm, Radius of bow- shaped leaf spring varies from (1250 to 3000) mm and constant load applied on the first leaf equal 1000N on each side. The number of cases studied equal 24 case. The finite element method was applied as a method of analysis to examine the stress distribution for each leaf.

The universal function approximation capabilities of multilayer feedforward neural networks make it a popular choice for modeling dynamic systems. In this paper, identification of dynamic system using time-delay feedforward neural networks with application to DC motor as a case study has been developed. The developed neural network model is a three-layer network with nonlinear (sigmoid) activation functions in the hidden layer and linear output layer with input-output delays. Simulation results showed that the neural networks are promising tool for dynamic system identification.

The aim of this paper was perpetrated lap joint welding samples welded by seam welding method ,2014 heat treatable aluminum alloy, the paper studied some groups at different variable welding, welding time was studied at electrode pressure 1,1.5 KN with thickness 1.5 mm and another group at 2 mm. after welding process shear strength, Vickers hardness were tested at different variables. The paper stated the best shearing strength at 1.5mm thickness with 45 KA welding current at 1.5 KN electrode pressure. Increase 0.5 mm in thickness lead to decrease 20% of shearing strength.

The application of empirical and quantum chemical models on the corrosion inhibition of steel in hydrochloric acid in presence of phenylthiourea (PTU) as corrosion inhibitor have been modeled. Two mathematical models were used, third order polynomial model and Arrhenius type equation model. Levenberg-Marquardt method was used to evaluate the coefficients of two Models. Two models were suitable to represent the corrosion rate data at different conditions. The correlation coefficient of third order model was 0.973, while for the Arrhenius type model was 0.919. The structure of inhibitor was optimized by ArgusLab 4.0.1 package. The quantum chemical parameters (EHOMO, ELUMO, ΔE, and dipole moment μ) were estimated by PM3-SCF method.

This research deals with the choice of the suitable filler metal or weld electrode to weld austenitic stainless steel (316L) by shielded metal arc welding (SMAW) and used four types of weld electrodes (E7018, E6013, E309l& E308l) under constant conditions such as plate thickness (6mm), welding current (120A), voltage (78V) ,reverse polarity(DCRP) .and diameter of (3.25) mm. Various inspections were carried out including visual inspection, x-ray radiography inspection, δ-ferrite phase and microstructure inspection. Mechanical tests were also conducted to include tensile testing, bending testing & microhardness testing. The results showed that the electrodes (E309L, E308L) are suited to weld stainless steel (316L). The results showed that the microhardness of the weld metal is higher than that heated affected zone (HAZ) and the base metal. The research results showed that (3.5%-4.5%) of δ-ferrite phase in weldment from (St.St 316L) by used electrodes (E309l, E308l) respectively.

The results of this research show that the heat treatment of the Copper-Tin alloy which used in this research with (900) °C at (15) min, with quenching in water, and reheating with (600) °C at (3) hours lead to best the mechanical properties, which include, tensile strength, toughness, Formability, because of a microstructure in which the fine phase is well dispersed uniformly in the matrix which leads to a remarkable reinforcement effect on mechanical properties.

Iraq is belong one of three areas in the world, with the highest temperature in summer. But normal wall and roof constructions in Iraq are often without any thermal insulations. The aim of this paper is to calculate the thermal resistance and thermal transmittance of usual Iraqi wall construction. This calculation depends on the thermal conductivity (λ) of different materials. Those calculations were compared with insulated wall construction values. As insulation material is a layer of expanded polystyrene (EPS) or extruded polystyrene (XPS) used in the calculations. The adding of this layer reduces the U-value for the construction to 0.431 W/m 2 .c 0 The result shows, that a wall construction consists of concrete hollow block-2chamber with 20mm external and 15mm internal plaster having U-value of 2.39 W/m 2 .c 0. This value is far away from the U-value of ≤0.5 W/m 2 .c 0 as standard value by countries with extremely hot summer.

Materials are considered essential resources to all of the industries including construction industry, because productivity process depends on it in basic method, therefore this important resource must be interested and the attempt of the search in the methods, which is possible throughout lead to controlling and following these materials. This research aims to evaluation process of movement and handling of materials on construction sites that following to Diyala University by using AHP technique to reduce and facilitate the handling cost and the cost of lose through it. This is done throughout determination of the used criterions to determination the optimum site from aspect construction materials management, and determination list to the companies working in the university of Diyala which choose the optimum company from this aspect .In order to satisfied this aim, a data collection have been made from some literatures about Analytic Hierarchy and construction materials management on construction site, then from the personal interviews with the specialists of designers and constructors in the construction companies .The results of data analysis of samples show that the criterions of schedule and supplying ,receiving the materials , store the materials , handling and distribution the materials , the lost in materials and to get rid of the excess materials have obtained a great portion of relative importance comparatively with another criterions between companies .and the criterions store the materials , handling and distribution the materials are more important than another criterions of the companies .The company of the project of teacher’s flats had obtained a great portion of relative importance comparatively with another projects .Finally, it has been resulted to set of conclusions and recommendations for different aspects of this subject, such as , the need to the management manners qualified essential to evaluation construction companies in the different aspects and specially in the field of construction materials management.