Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 30, Issue 15

Volume 30, Issue 15, September 2012, Page 329-2745


Experimental and Numerical Study of the Effects Of Creating Openings in Existing RC Beams and StrengtheningWith CFRP

Hayder Qais Majeed

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2550-2561

This study presents an experimental and nonlinear finite element analysis of creating square openings in existing RC beams and strengthening with CFRP laminate. Flexural strengthening of reinforced concrete beams is now becoming more and more important in the field of structural maintenance and retrofitting. In the experimental programming, three RC beams were cast. Two beams were tested in the un-strengthened condition the first act as the solid Control beam, and the other have openings, the third one have opening and strengthening with CFRP laminate. The beams were also modeled using a FEM packaged (ANSYS 11). The results indicate that the strengthened beam recorded the highest failure load and its mode of failure was ductile. The numerical results seemed to be able to predict the behavior of the beams.

Method for Shielding the Magnetic Field Generated in a 132/33/11(6.6)KV Baghdad Indoor Distribution Substation

Suad I. Shahl

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2562-2576

This research introduces the study carried out on one of Baghdad East 132/33/11(6.6) kV distribution substations to mitigate 50Hz magnetic field of indoor distribution substation under normal operation. Shielding was performed at the power sources such as busbars rather than at the affected areas. Three-dimensional finite element method (FEM) is used to calculate the magnetic field density in the space nearby the busbars so as to analyze the shielding effectiveness of an eddy current shield applied to a 132/33/11(6.6)kV substation. It also deals with the influence of shield distance from busbar, thickness and material of shield on the eddy current losses and shielding efficiency applied to 3D finite element model of a particular busbar configuration.

Numerical Study of Two-Dimensional Transient Natural Convection in an Inclined Shallow Porous Cavity Exposed to a Constant Heat Flux

Jasim M. A. Al-lateef; Ayad K. Hassan

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2577-2596

Numerical method is used to solve the two-dimensional transient natural convection heat transfer problem in an inclined shallow porous cavity. A constant heat flux is applied for heating and cooling all opposing walls. Solutions for laminar case are obtained within Rayleigh number varied from 20 to 500 and aspect ratio for porous cavity varied from 2 to 4. A finite difference method is used to obtain numerical solutions of full governing equations. Energy equation is solved using alternating direct implicit (ADI) method and stream function equation by successive over relaxation (SOR) method. The results are presented for the flow filed, temperature distributions, and average Nusselt number in terms of the Rayleigh number, aspect ratio, and the inclination angle of cavity. the convection becomes more and more vigorous as the orientation angle of the cavity is increased and for high Rayligh number no steady unicellular flow could be maintained inside the cavity. The effect of inclination angle on Nasselt number is more pronounced as the Rayleigh number is increased. When the inclination angle increased the Nusselt number increased and sudden transition appears and flow becomes unicellular and Nusselt number increased clearly. The value of mean Nusselt number strong function with the value of Rayleigh number, aspect ratio and the orientation of porous cavity.

Numerical Study of a Solar Chimney Power Plant

Rafah A. Najim; Jalal M. Jalil

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2597-2608

Axi-symmetric, steady, incompressible, turbulent flow field developed by natural convection inside power plant solar chimney is investigated numerically using finite volume method. Navier-Stockes with energy equation is solved to achieve velocity components and temperature distribution inside solar chimney. To complete the thermal analysis, conduction through upper glass wall, chimney concrete wall and floor ground were investigated to calculate temperature distribution through theses walls. A standard turbulence model associated with lawss of the wall along solid boundaries was used. Special arrangement for mesh was used to deal with complicated shape of the domain. The main studied parameters are solar collector diameter, kinds of ground, periphery heights and solar intensity radiation. This study was compared with previous available experimental study and there is acceptable agreement. The performance of the solar chimney was examined through maximum air velocity in the tower inlet and maximum temperature in the ground floor. The final optimization parameters are defined within studied ranges.

Adsorption of Direct Yellow 4 Dye on the Silica Prepared from Locally Available Sodium Silicate

Sameer Hakeem Kareem; Manal Obeid Hamza

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2609-2625

In this study the ability of removing direct yellow 4 dye (DY4) from aqueous solutions using silica as adsorbent was examined. The silica was prepared from locally available sodium silicate. The effect of various experimental parameters contact time, amount of silica used, pH, ionic strength and temperature were investigated in a batch adsorption technique. The obtained experimental data shows that, the adsorption of direct yellow 4 dye was increased directly with increasing concentration, amount of silica, added sodium chloride and temperature in optimum pH (7) and equilibrium time of 45 min. The kinetic data were analyzed through pseudo first-order, pseudo second-order and intraparticle diffusion models. The pseudo second-order model best represented adsorption kinetics. Additionally, this study used the Langmuir, Freundlich and Temkin isotherms to describe equilibrium adsorption and calculating thermodynamic values. The equilibrium adsorption of direct yellow 4 on silica is best fitted in the Langmuir isotherm (R2 =0.981).

Prediction of the Best Electrode Geometry of Resistance Spot Welding RSW Theoretically by FEM and Experimentally

Khalil Ibrahim Abass

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2626-2640

The present research studies five spot welding electrodes (RSW) of different geometries. The design of each electrode considerers contacts shape and area of the welding spot. The considered welding electrodes are (Flat, Round, Project, PunchFlat, Cross Flat). A simplified mathematical 2D-axisymmetric model is used to study the behavior of each electrode. It is solved numerically using Finite Element Method (FEM). The model describes the nature of welding contact in terms of contact locations, contact pressure and stress distribution. The model is validated by performing tensile shear tests on the welded specimens resulted from each electrode. Results show good agreement between the estimated behavior and the performed tests. The strength of welding appeared to be proportional to welding time for all five electrodes considered. The type (Project) gives the highest shear strength and the type (PunchFlat) gives the lowest shear strength. The tests show that the electrode of the type (PunchFlat) produces a hole in the welding area. This is caused by the electric spark in the gap between the upper electrode and the plate. The same defect is noticed in the type (Round). In both types, this phenomenon is attributed to the stress concentration in a narrow area which eventually causes the punch.

Lateral Resistance of a Single Pile Embedded in Sand with Cavities

Laith Jawad Aziz; Mahmoud R. Mahmoud; Kais T. Shlash

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2641-2663

The research presents an experimental study of the interaction between cavity and adjacent pile in sandy soil. Experimental studies were performed to investigate the effects of the different factors (such as cavity locations, batter angle of pile, pulling height and vertical dead loads) on the lateral movements, rotations, and ultimate lateral resistance of the pile for three states of soil (dry, water at rest and water flowing laterally).
The analysis of the experimental results of the dry models indicate that the model tests for very deep or shallow cavity with negative distance ratio( the horizontal distance from the centerline of the pile to the centerline of the cavity, S/B=-8) carries more load than the cavity case with positive distance ratio. Different failure modes can be observed for each model tests depending upon the geometry of the problem. The resistance of the batter pile are generally smaller than that of the vertical pile case for cavity with ( depth of the cavity to length of the pile, D/L=1 and S/B=0). Also for the same cavity location, the effects of lateral load position on batter pile are very low. The pile with vertical dead load of (228.6 N) carries more lateral load than pile with no vertical load for the same cavity condition. This behavior is reversed for soil without cavity. In spite of that the constant lateral load is greater than the ultimate lateral resistance of the case (F.S=0.8) during the observations of the lateral displacement with time, failure does not occur for cavity condition with (D/L=0.5 and S/B=-8).
The results of the model tests with the presence of the water show the methodology of the water flowing in the lateral load direction is more dangerous on the pile stability than water at rest state for no cavity condition, but the water at rest becomes very dangerous state for any cavity condition.

Enhancement of Carbon Dioxide Absorption in Caustic Soda by Organic Solutes Addition

May Ali Muslem; Ala; a Mshcheil Ali; a Abdul Hadi Noori; Walla

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2664-2677

Absorption of carbon dioxide in a bubble column by 0.5M Sodium Hydroxide aqueous solution with and without various organic compound concentrations of glucose, fructose and saccharose”0.05 , 0.2 , 0.4M” and various superficial gas velocities “0.008 , 0.012 , 0.016 m/s” were studied in the present work.
The experiments were conducted under conditions in which the reaction of carbon dioxide was of Pseudo-first order. The results show that the absorption rate enhances with organic solute additive and increasing solute concentration.

GPR Data Simulation for Detecting Subsurface Bodies

Haidar A. N. Al-dami; Hussein H. Karim

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2678-2693

Ground-penetrating radar (GPR) technique was used at University of Technology-Baghdad, as a non destructive, quick, low cost and powerful technique in detecting any change in the constituents of subsurface as materials which can be consequently applied in urban and constructed areas. The main objectives of this study are: to simulate GPR data obtained by 250 and 500 MHz antennas for shallow engineering investigation by detecting different subsurface bodies. A simulation is made for GPR data with different geometric buried bodies and located at different depth. Before processing, most of the raw data of radargram do not reflect the presence of the buried bodies. But after processing by using suitable filters and other interpretation tool parameters, many of the investigated subsurface bodies and structures appeared clearly. It is found from this study that the degree of clarity of the buried bodies do not depend on the higher value of dielectric constant of the body, but it depends on the contrast between the body and the host medium. Thus the body with low dielectric constant appears more clear than that with higher dielectric constant, when they are at the same depth. Most of the buried bodies appeared on GPR radargrams using the medium frequencies. The best detecting depth are 1.5 m to 1 m for 250 and 500 MHz antennas respectively.

Theoretical Study of Vibration Frequencies of Fullerene Molecule (C60) by Using Density Function Theory (DFT)

Hasan R. Obayes

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2694-2700

Fullerene molecule C60 was studied optimize structure, harmonic vibration frequencies, infrared active vibration modes and some physical values in the gaseous state theoretically by using Density function Theory (DFT), from view animations of the mode displacement patterns, the infrared active vibration modes can be classified theoretically to; Twisting vibration for (=C-C=C-) group at 510.0 cm-1, Wagging vibration for (=C-C=C-) group at 579.8 cm-1, Stretching vibration for (C-C) bond in 1165.6 cm-1 and Stretching vibration for (C=C) bond at 1464.7 cm-1. These results were compared with other calculation data and experimental measurements. Two from these modes are in good agreement with experimental measurement while the two are nearly approach.

Strength and Ductility of Concrete Encased Composite Beams

Ammar A. Ali; Saad N. Sadik; Wael S. Abdul-Sahib

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2701-2714

Experimental research was conducted to investigate the structural behavior of concrete-encased composite beams. Specimens were tested under lateral loading. The test results indicate that the behavior and failure mode of the beam are greatly affected by the steel beam core. The beams showed highly ductile behavior. The design flexural strength of concrete-encased beams is calculated from both the elastic and plastic stress distribution on the composite section. The deflection at the mid-span of the beam cannot be well predicted using linear elastic theory.

Conversion of Glycerol into Value Added Products by Catalytic Processing

Nidal Al Derzi

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2715-2724

The conversion of glycerol into value added chemicals have emerged in recent years as a result of glycerol unique structure, properties, bioavailability, and renewability. Glycerol is produced in large amounts during trans-esterification of fatty acids into biodiesel, and as such represents a useful by-product.
In this paper, the liquid phase oxidation of glycerol has been studied over gold nanoparticles supported on TiO2, and synthesized by using deposition-precipitation method. The catalysts are characterized by XRD, TEM, XPS, and activity towards CO oxidation. Active catalysts comprise particle size distributions (2-5 nm diameters) for gold nanoparticles. The results indicate that the Au/TiO2 catalyst showed the best performances both for activity and selectivity toward glyceric acid. We have also studied the effect of reaction conditions such as, amount of catalyst and concentration of base in the catalytic activity.

State Estimation of Direct Field Orientation Control Induction Motor Drive by Using Kalman Filter

Mohammed Khalil Hussain

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 2725-2745

Field oriented control (FOC) method of an induction motor (IM), allows high performance speed and torque response to be achieved from an induction motor. The present work selects the direct field orientation control induction motor (DFOCIM) as an effective method for eliminating the coupling effect between torque and flux. In the present work, two schemes of estimators have been used, standard kalman filter (SKF) and Extended kalman filter (EKF) for estimating stator current, rotor flux and rotor speed. The performance comparison is based on evaluation of estimation error of both estimators. The performances of suggested estimators are assessed in terms of tracking performance and noise rejection capability.

Studying the Effect of Corrosive Liquids on Pipes Properties of Unplastizied Polyvinyl Chloride (UPVC) Which is Used in Sewage Purpose

Ahmad Star Ali

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 329-340

The current study concerns with studying some mechanical and physical properties of different samples taken from Unplasticized Polyvinyl Chloride (UPVC) pipes used in sewage purpose. Impact strength, compressive strength, shore-D hardness, and diffusion coefficient also were calculated for the samples immersed in different solutions (Wastewater, HCl-0.5N, and Tape water) for four months. Results showed that the mechanical properties of samples were affected by solutions and reduced by (3 – 5)% for impact strength and (10%) for compressive strength. Values for diffusion coefficient (D) were calculated, it
was found that (HCl-0.5N) had a higher value, followed by wastewater then tape water. No cracks were observed, and there were no changes in sample’s dimensions after immersion in solutions.

Establishing Reform System for Preparing Bills of Quantities

Sagid Mahdi Aamran

Engineering and Technology Journal, 2012, Volume 30, Issue 15, Pages 341-362

Bills of Quantities (B.Q) considered as one of the important project documents in addition to the contract form and the exchanged official letters between the two main contract parties before signing a contract. Quantities estimation performed through two stages, the first is to determine measurements from design drawings to find length, number, area, and volume, for each group of works, its related units in an organized manner prior to the preparation of the required (B.Q). The responsible party of preparing (B.Q) should be aware in all estimating methods and have wide and detailed information about building materials, construction methods, site conditions, and prices changing with time.
Due to the lack of accuracy, organizing, and standard specification of the existing (B.Q) which prepared by different public and privet contracting companies and that observed through this research, therefore there is clear importance to establish reform system for the prepared (B.Q).Through theoretical, field investigation and studies, several factors affecting the accuracy of (B.Q) are concluded by this research. Deficiencies in (B.Q) are the result of the responsible party lack of awareness' regarding the concluded factors.
The researcher established computer program to simulate the effecting factors on accuracy of (B.Q) and recommend the required reformation to each examined case. The research recommended that (B.Q) preparing parties to consider all concluded affecting factors or at least the very effecting ones and to adopt the proposed system for reforming their prepared (B.Q).