Print ISSN: 1681-6900

Online ISSN: 2412-0758

Issue 2,

Issue 2


Effect of Particle Size on the Physical and Mechanical Properties of Nano HA/HDPE Bio-Composite for Synthetic Bone Substitute

Jenan Sattar Kashan; Jafar.T.Al-Haidary; Amin D.Thamir

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 286-297

The effect of using nano particle size of Hydroxyabatite to produce HA/HDPE biocomposite
by Hot Pressing technique was studied by investigating the effect of particle
size and production technique on the physical and mechanical properties of the biocomposite
at different volume fraction of nano HA powder and different compression
pressures.
Nano particle size and Hot Compression technique had great impact on the properties
by reversing the behavior of the bio composite comparing with that using micro scale
particle size in some of previous studies .The fracture strength and hardness increased
with increasing the filler content by more than 200% for strength and 300-400% for
micro hardness values , the densities increased with increasing filler content
compressing pressure where as the porosity decreased.
The modification in mechanical properties due to filler particle size and production
process enhanced the osteo- conductivity of biomaterial to use in different bone substitute
applications.

Optimizing Overcut Parameter of Micro-Holes Machining by EDM Using Taguchi Method

Laith A. Mohammed; Shukry H. Aghdeab

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 298-304

In this paper Taguchi method was performed to estimate the optimum overcut parameter for Electro Discharge Machining (EDM) to obtain micro-holes of copper alloy workpieces. Taguchi method is used to formulate the experimental layout, to analyses the effect of each parameter on the machining characteristics and to predict the optimal choice for each machining parameter (current, gap distance and machining time), and analyzed the effect of these parameters on the overcut parameter. The
analysis shows that, the current significantly affects the overcut parameter.

OFDM Channel Estimation Based on Intelligent Systems

Ismail Mohammad Jaber; Hanan A. R. Akkar; Haraa Raheim Hatem

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 305-324

This work is dedicated to the study of reducing Bit Error Rate (BER) when transferring data in the system Orthogonal Frequency Division Multiplexing (OFDM) by estimating the carrier channel in different ways. The proposal design for Artificial Neural Network (ANN) is considered as a tool to improve performance BER and compared with the traditional method based on the use of the Least Square estimation algorithm (LS) to estimate the impulse response of frequency selective Rayleigh fading channel. A MATLAB 7.14 program is used in simulation.
The proposed method which integrates algorithm LS with ANN includes the following:
1. Training the neural network by Back-Propagation (BP) and using the trained neural network with algorithm (LS) to estimate the channel in different paths.
2. Using Resilient Back propagation algorithm (RProp)in the training of the neural network.
3. UsingLevenberg-Marquardt algorithm (LM) in the training of the neural network.
4.The comparison of results between the traditional method and the proposed method when taking BER = 0.001 at various tracks (one path, two path and three path) and showed that there profit of (1.5dB, 2dB, 2dB) between using the traditional method and the proposed method using RProp algorithm and a profit of (2dB,3dB, 2dB) using an algorithm LM. There is also comparison between the performance ofRProp algorithm and LMalgorithm and the results showed that the LM algorithm better thanRProp algorithm.

Numerical Analysis of the Effect of Weld – Joints Preheating on Temperature Distributions In GMAW

Abbas Sh. Alwan; Jalal M. Jalil; Muna K. Abbass

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 325-338

In this research , medium carbon steel type (AISI 1045 ) sheets with 8 mm thickness were welded by Gas Metal Arc Welding Process (GMAW), this study included the application of numerical analyses by using control volume method (CVM) to obtain the effect of preheating process with different temperatures (75 ˚C , 125 ˚C and 225 ˚C ) on temperature distribution of the welded joint in addition to determination of cooling rates which were achieved for 3-D heat transfer in the weldment. Results showed the analyses contributed effectively to predict the temperatures distribution for the welded joint and get mathematical models for the cooling rates at welding variables ( welding speed was equal 2.5 mm / sec , and welding current was equal 180 Amp ) with different preheating temperatures.

Fingerprint Recognition Using Gabor Filter with Neural Network

Ekbal H.Ali; Hussam A.A.Ali; Hanady a.Jaber

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 339-353

The automated classification and matching of fingerprint images has been a challenging problem in pattern recognition over the past decades. This paper proposes a method to detect the rotation region based on Estimate Global Region (EGR) that has the maximum rotation region. The Gabor filter based feature is applied for extracting fingerprint features from gray level images without preprocessing. The fingerprint recognition is developed by neural networks with adaptive learning rate. The paper contains a comparison between using EGR algorithm and without using EGR. The Gabor filter without EGR gives the best result for the fingerprint recognition with outrotation while the rotation of the fingerprint with angles (5o,10o and 20o) gives worse results in fingerprint recognition. The proposalmethod gives best result in rotation the fingerprint image with and without the rotation of the same angles. The result of the correlation for the proposalmethod is 99%.

Corrosion Behavior for Al-Cu-Mg Alloy by Addition SiO2 Particles in Seawater

Rana A. Majed; Mervit Mahdi; Hanaa A. Al-Kaisy; Saja A. Abdul Maged

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 354-364

This work involves studying the effect of adding SiO2 particles on corrosion behavior of Al-Cu-Mg alloy in 3.5% NaCl solution at room temperature using polarization method at scan rate 3 mV.sec-1.
According to potentiodynamic polarization test, the results of corrosion rate indicate that Al-Cu-Mg composites (1, 2, 3 wt% SiO2) gave decreasing in corrosion rate compared with Al-Cu-Mg alloy due to the covering the anodic sites for alloy by SiO2 particles and enhancing the passivity of surface and reducing the dissolution of aluminum. The cathodic Tafel slope (bc) were decreased after adding SiO2, while the anodic Tafel slopes (ba) were increased. It is inferred that the rate of change of current with change of potential was smaller during anodic polarization than that during cathodic polarization. Cyclic polarization measurements were carried out to estimate the pitting resistance of Al-Cu-Mg composites. The results show that a stable oxide film is formed during the forward scan on the surface of composites; also the hysteresis loop disappears, especially for composite with 3 wt%SiO2.

Fe Analysis of Residual Stresses Induced by Spot Welding of Stainless Steel Type Aisi 316

Ahmed N. Al-Khazraji; Samir A. Al-Rabii; Ali Hussein F. Al-Jelehawy

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 365-384

Specimens of the as-received stainless steel type 316, according to AISI standard, in form of sheet with 1.5 mm thickness were first spot welded and thenshot peened to obtain the influence of shot peening process on the residual stresses induced by spot welding process. X-Ray Diffraction (XRD) method was used to measure the residual stresses. Also, a finite element method (FEM) was employed by ANSYS software version 11 to achieve the simulations for transient thermal analysis and residual stresses analysis in all cases. In addition, the temperature dependency of materials properties was used to assess its effects on the final residual stress results. A comparison showed a very good agreement between the experimental and the numerical results due to the total elimination of tensile residual stresses and creating the compressive type instead.

Edge Detection Using Scaled Conjugate Gradient Algorithm in Back propagation Neural Network

Walaa M. Khalaf; Mohammed Ali Tawfeeq; Kadhum Al-Majdi

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 385-395

This paper introduces a proposed method based on a backpropagation artificial neural network using Scaled Conjugate Gradient (SCG) training algorithm so as to gain the edges of any image. A new training image model is suggested to train this artificial neural network, then using this network to find the edges of any image. Computer experiments are carried out for extracting edge information from real images; the results presented are compared with those from classical edge detection methods like Canny. Using this new method does not need to tune any parameter to find the edge of any image, as well as using this method the false edges is reduced.

Design Aspects and Sensitivity Analysis of Tenth Order Active Bandpass Filter

Muneer A. Hashem; Wail I. Khalil; Raad B. Raheem

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 396-413

The design and sensitivity aspects of five stages tenth order active bandpass filter suitable for signal processing in electronic circuits are introduced. Simulation process performed is started by evaluating the voltage transfer function of the filter using the nodal approach to the second order activenet work model which represents each stage. The sensitivity analysis with respect to some parameter changes such as resonance frequency and quality factor is treated for proper choice of component values. The computational difficulties in the analog domain manipulations that arises through the cascaded arrangement of the filteris overcome by factorizing the terms in the denominator of the stated voltage transfer function with the aid of MATLAB 7.10.0(R2010a)software program. It was found that the increasing in the quality factor increases the magnitude, phase responses, higher deviation in magnitude sensitivity due to change in resonance frequency and lower frequency range due to change in quality factor. An increasing in the resonance frequency results in a better impulse and step response. The phase sensitivity due to change in resonance frequency shows that an increase in the quality factor gives higher deviation and this deviation is less in the sensitivity due to change in the quality factor. The simulation process of the circuit is done via the introduction of the Multisim software package version 9.0.155, offers good agreements with the results obtained.

Design and Simulation of 11/0.4 kV Distribution Transformer Using ANSYS

Thamir M. Abdul Wahhab; Methaq Talib Jabbar

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 414-438

This work presents a Finite Element Method (FEM) modeling of a 3-phase, 11/0.4 kV, 50 Hz, oil immersed, core (stack) type distribution transformer. In this work The ANSYS package is used to build the finite element model of the transformer, using actual transformer parameters. To investigate transformer performance several analyses are accomplished on this model such as; static analysis, transient analysis, harmonic analysis. Two types of analysis are considered; the linear analysis (using constant permeability) and the nonlinear analysis using the B-H curve of iron. The results are presented in 2D vector and contour colored plots of the FE model, the voltage and current curves, the magnetic flux lines, flux density, field intensity, current density, and magnetic forces.

Study Fatigue Behavior of Friction Stir Welded Joints for Dissimilar Aluminum Alloys (2024 -T3 and 7020 -T6)

Muna K. Abbass; Ali H. Ataiwi; Ahmed Ameed

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 439-452

The aim of the present work is to investigate the fatigue behavior of friction stir welded joints for dissimilar aluminum alloys (2024 -T3 and 7020-T6). Friction stir welding (FSW) had been done for 6.6 mm thick plate by using NC milling machine with R18 tool steel of 18mm with shoulder diameter and 6mm pin diameter with different tool designs; threaded cone with double bevel, threaded cylinder with concave shoulder of 4°, and beveled cone with concave shoulder of 4°. FSW were carried out under various welding parameters, travel speed of 40, 50, 75 mm/min, rotation speed range (275-1250) rpm and tilt angle of (Ɵ = 3°) with counterclockwise revolution.
Many non- destructive inspections and mechanical tests were performed to evaluate welded joints to determine the best welding parameters. Fatigue test has been done at constant stress amplitude cantilever with stress ratio of (R= -1). The results showed that maximum tensile strength and joint efficiency were 360MPa and 86% respectively for dissimilar joints which were welded at 40mm/min travel speed and 550 rpm rotation speed by using threaded cone with double bevels.

Power Management of LED Street Lighting System Based on FPGA

Hanan A.R Akar; Naseer K. Kasim; Noor A. Jasim

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 453-464

Light Emitting Diode (LED) lamp is new lighting technology used over the world, its high efficiency, low power consumption, dimming capability, long lifetime, environmental friendly and much more advantages make it preferred source in new outdoor and indoor lighting systems. The method of time-control is used to manage the power consumption of an LED using Very high speed integrated circuit High level Description Language (VHDL) program and implement the design using Field Programmable Gate Array (FPGA) /Spartan 3A starter kit. Two dimming scenarios are implemented to reduce the power consumption of LED, Pulse Width Modulation (PWM) technique is used as dimming method and based on real time clock designed using (VHDL) program and was implemented on the same FPGA kit. 70% annual energy saving was achieved using first dimming scenario and 71.4% with second scenario compared to High Pressure Sodium (HPS) lamp and about 20.1% power saving using first scenario and 23.7% with second scenario compared to normal LED operation.

Dynamics and Control of Heat Exchanger Networks

Duraid Fadhil Ahmed; Cizan A. Ali

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 465-480

In this paper dynamics of plate heat exchanger networks is given by combining dynamic models of plate heat exchangers in the network. A mathematical model for plate heat exchanger is developed based on energy balance. Dynamic simulation of plate heat exchanger networks to different step changes in flow rate of both process fluid and utility fluid is conducted using MATLAB simulink. Plate heat exchanger networks has been controlled using split range control method with two manipulated variables which are process fluid and utility fluid. The simulation results showed that split range controller is the best action and gives better response compared with conventional controller.

Suboptimal Resource Allocation for MIMO-FDMA Systems

Salah AwadAliesawi

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 481-493

In this paper, a pragmatic resource allocation algorithm for single-cell downlink multi input-multi-output (MIMO) based orthogonal frequency division multiple access(OFDMA) systems is proposed. The objective of this method is to maximize the average system throughput as a function of bit error rate and (BER) spectral efficiency by allocating the users, transmission power and information bits across the utilized subchannels. The resulting throughput maximization problem has been decoupled into two sub-problems to reduce the computational complexity, however, at the expense of performance a sub-optimal solution is obtained. The simulation results of the throughput and outage probability, obtained using MATLAB simulator, show the efficiency and accuracy of the proposed system in comparison with the other approaches.

Numerical Investigation of Energy Storage in Packed Bed of Cylindrical Capsules of PCM

Ahmed K. Alshara; Mohammed Kh. Kadhim

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 494-510

A theoretical study of storage thermal energy using capsulated cylinders filled with phase change material PCM is performed. These cylinders are arranged in-line in the direction of heat transfer fluid. The energy equations of fluid (water) and PCM capsules are solved numerically using finite volume method with heat capacity method for phase change of PCM. The effect of Reynolds number and the ratio of pitch to diameter of the cylinders on the temperature distribution and melt fraction are presented. The results show that the increment of both Reynolds number and the ratio of the pitch to diameter gives decrement in the final time of melting of PCM in the cylinders.

Punching Shear Resistance of Reinforced Concrete Flat Plate Slabs Strengthened with CFRP

Eyad K. Sayhood; Mohammed J.Hamood; Aseel A. Abdul Ridha

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 511-529

The purpose of this study is to present a model suitable for analyzing reinforced concrete (RC) slabs strengthened with Carbon fiber reinforced polymer (CFRP) failing in punching shear using the finite element method. a nonlinear three-dimensional finite element analysis has been used to conduct an analytical investigation on the overall behavior of reinforced concrete slabs strengthened with CFRP strips. ANSYS (version 11, 2007) computer program is utilized.The 8-node isoparametric brick elements in ANSYS are used to represent the concrete, the steel bars and CFRP strips are modeled as axial members discrete within the concrete brick elements by assuming perfect bond between the concrete and steel and between the concrete and CFRP strips. The numerical analysis incorporates material nonlinearity due to concrete cracking in tension, nonlinear stress-strain relations of concrete in compression, crushing of concrete and yielding of steel reinforcement. Also, the evaluation of the CFRP strips enhancement in shear strength of RC slabs is investigated.
Different types of RC slabs strengthened with CFRP strips have been analyzed. Available experimental results are chosen to check the validity and the accuracy of the adopted models. In general, a good agreement is obtained between the finite element and the experimental results. The maximum percentage difference in ultimate load-carrying capacity is 8.83%. Several parametric studies have been carried out to investigate the effects of some important material parameters on the behavior of strengthened RC slabs. These parameters are the concrete compressive strength, the concrete tensile strength, the number of layers of CFRP strips, the configuration of CFRP strips and the effect of diagonal stirrups of CFRP.

Influence of Adding Different Amounts of Super Plasticizers on the Mechanical Properties of Concrete (Impact and Abrasion)

Ali Hussain Ali; Mohammed Hazim Yasin

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 530-550

Trial laboratory batches were used to study the effect of adding different amounts of superp lasticizers on the mechanical properties (Compressive strength, abrasion resistance, and impact resistance) of concrete. A series of five different concrete mixtures including: Normal concrete mixture C1 (without superp lasticizers) as a reference mix and four concrete mixtures (C2, C3, C4, and C5) with different amounts of superp lasticizers (0.25, 0.50, 0.75, and 1.00) % as a percentage of cement content, respectively. Results show that the (1.00)% addition of superp lasticizers in the concrete mixture leads to (19.84)% increasing in the compressive strength and records an improvement in the abrasion resistance by (38.06)% and recorded an improvement in the impact resistance by (386.67)% as compared with the reference mixture. On the other hand, increasing the percentages of superp lasticizers lead to increase in compressive strength, abrasion resistance and impact resistance for all concrete mixtures.

Evaluation of Mechanical Properties of Roller Compacted Concrete

Mohamed Abdul-Razzaq Ahmed; Hisham K.Ahmed

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 551-572

The main aim of this research is to study the effect of using the additive materials (hydrated lime and metakaolin) on the behavior of roller compacted concrete. The experimental work includes several trial mixes to choose the most suitable roller compacted concrete mix in terms of physical concrete properties. The first step is to specify the optimum cement and water content which is designed in laboratory using 300 kg/m3 of cement and 0.5 W/C ratio while the second step the only variation is using the optimum sand content of 700 kg/m3 and the third step the variation is using the optimum percentage of the additive materials (metakaolin and hydrated lime) at percentages (5%, 10%, 15%, 20% and 25%) as a partial replacement by weight of cement, the optimum percentage of 15% of (HL and MK) as a partial replacement of cement at different ages. The research also includes studying the physical properties (compressive strength, splitting tensile strength and flexural strength) of specimens with additive materials and without additive materials. Also the results of RCC specimens with additive materials (MK and HL) show improvement in compressive strength, splittingtensile andflexural strength (modulus of rupture) compared with the specimen without additive materials.

In-Between Space Iin Architecture A Study in the Nature of Active In-Between Space

Asmaa M.H.Al-Muqaram; Jinan Hassan Al- Anbaki

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 19-43

The in-between concept has emerged as one of the basic concepts in the architecture which was based at a bilateral relationship between two contradictory objects. Some studies focused on bilateral relationship between the two objects while others have stressed the abolition of the existence of these two objects so that the (in-between) space becomes the base to shape the object. Thus, the in-between concept has appeared either as an implicit or as an independent concept that can affect and be affected by its surroundings. Consequently, previous studies did not give an appropriate clarification of this concept. The research problem is (the lack of enough perception of the in-between space characteristics in architecture, particularly the nature of the active in-between space),and the objectives are (first: determine the characteristics and types of the in-between space in architecture in general, second: determine the characteristics of the active in-between space) .
To achieve this it is necessary to put forward a methodology consist of three steps, first: formulate conceptual framework about in-between space which restructured into two main concepts (A: the in-between space properties as a third space and B: the active in-between space properties) . This leads us to build an intellectual hypothetical in-between which composed of four major states : (liminality - threshold - interstitial - transitional) , second : conducting practical study, identifying the measurement, two selected samples were identified for application, the first one is the “University of Technology” for improvised growth, the second is “Baghdad University” for planned growth, then identifying the two main concepts for application (the nature of active in-between spaces properties).Third : put forward Finding and conclusions .

Study The Effect of Rotational Speed and Pouring Temperature on the Distribution of Si in Functionally Graded Material Produced by Centrifugal Casting

Nawal Ezzat Abdul-Latiff; Rabiha Salih Yaseen; Abdul-jabbar Saad Jomah

Engineering and Technology Journal, 2014, Volume 32, Issue 2, Pages 44-61

The aim of this study was to prepare a functionally graded material using centrifugal casting process and study the effect of process parameters (the rotational speed of casting mold and overheating temperature) on the microstructure of a hypereutectic( Al-23%Si) alloy. The melt was overheated to( 800,900) Cº and poured in the centrifugal casting mold preheated to (100) º C ,and rotated at different rotational speed (765,840,1043,1712,1878) r.p.m . The microstructure observation showed that the increasing of overheating temperature will increase the average volume fraction of primary silicon and decreased the grain size of silicon. Increasing mold rotational speed will increase the average volume fraction of primary silicon in the inner layer of cylinder and decreased it in the intermediate and outer layer of cylinder. Increasing mold rotational speed will also decreased the grain size of primary silicon. The results of wear tests showed that the maximum wear resistant was found in the inner layer of cylinder produced using rotational speed (1878) r.p.m and pouring temperature (800) º C, minimum wear resistant was found in the intermediate layer of cylinder.