Print ISSN: 1681-6900

Online ISSN: 2412-0758

Issue 3,

Issue 3

The WLAN/ WCDMA Blind Multimode Wireless Receiving System

Sattar B. Sadkhan; Hanan A. R. Akkar; Dr.Wafaa M. R. Shakir

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 386-399

This paper proposes a new multimode wireless receiving system based on Blind Source Separation (BSS) for Orthogonal Frequency Division Multiplexing (OFDM) signal (based on Wireless Local Area Network (WLAN)) and the Wideband Code Division Multiple Access (WCDMA) signal (based on 3G cellular system). The proposed system applied the Independent Component Analysis (ICA) algorithms (adopting Fast-ICA and JADE algorithms) for blind estimating of the received signals. The processes of estimation, detection of the signals and equalization of the channel effects are done as blind methods at the same time. A performance comparison of the adopting algorithms had been done and the simulation results show that the multimode receiving system based on Fast-ICA algorithm had a gain of (7 dB) over JADE algorithm for a (10-4 BER) of 30 users WCDMA blindly signal detection.

Microstructure Investigation of Using Slope Plate Casting Hypereutectic Al-Si Alloy

Nawal Ezat; Osama Ibrahim

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 400-415

In this work, the effects of the overheating temperature and tilt angle on the microstructure and hardness of a hypereutectic Al-23%Si alloy were investigated. Al-23%Si melt was overheated to (760, 790, 820 and 850) ºC and poured onto slope plate continuously cooled with water circulation underneath, with various tilt angles (40, 50, 60)º using a constant cooling length (300 mm(. After, the melt became a semi-solid; the slurry was then filled the mould and completely solidified. Slope plate samples were reheated to a semi-solid temperature (550)ºC for (10 min) and then quenched in water.
Microstructural images analysis showed that the grain size and the shape factor of (β-Si) phase were decreased with increasing of the overheating temperature and tilt angles, on other hand, the volume fraction of (β-Si) phase was increased. The results of the reheating route showed that the grain size of (β-Si) phase was slightly increased after reheating at all overheating temperatures and tilting angles. On other side, the shape factor was improved, and the volume fraction of (β-Si) phase was decreased, as compared with slope plate results.

Experimental Study of the Effect of Shot Peening on Elevated Temperature Fatigue Behavior of 7075-T651 Al. alloy

Hussain J. Al-Alkawi; Shakir Sakran Hassan; Salah F. Abd-El-Jabbar

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 416-433

There is a general interest in increasing the fatigue life of materials. Shot peening is the process commonly used in order to increase the fatigue strength and life of 7075-T651. The effect of a combination of processes, fatigue-creep interaction and shot peening has not been thoroughly investigated so far. The aim of the present investigation was whether further improvements can be achieved by a comb/*ination of the two treatments. Two level experiments (cumulative fatigue damage programe) were used in order to determine the optimal set of process. It was found that the combination of shot peening and fatigue-creep interaction could be applied successfully in order to increase fatigue life for some specimens. Results of variable loading test clearly indicate that Miner rule does not give accurate and reliable predictions on fatigue lives.

Estimation of Liquidus Temperature of Duplex and Austenitic Stainless Steel

Nassier Abdul-Hussain Nassir; Riad Harwill Abdul Abas

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 434-449

Differential Thermal Analysis (DTA) and high frequency )HF( coil measurement were carried out in present work in order to measure the liquidus temperature of some austenitic and duplex stainless steel samples made by different steel companies in Sweden. A good agreement between the measured and thermal calculated values using Thermo-Calc software (Appendix 1) was found. The liquidus model used 1986 shows a lower value for most of these alloys. When the nitrogen gas used as an inert gas, the nitrogen content increased in the alloys because of the increasing of nitrogen solubility at high temperature. On the other hand, the nitrogen content decreased in the alloys when the argon used as an inert atmosphere because of the different partial pressure of nitrogen between the liquid alloy and the atmosphere. This changing has an effect on the microstructure and liquidus values especially in high nitrogen content alloys.

Coloring the Layer Thickness of Anodized Aluminum by Integral Color Process

Talib M. Naieff Al-Bayati

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 450-469

The identification of the self coloring process in anodizing process is integral color. In this research specimens of pure aluminum (1000) and AA 5056 anodized by using Alternative Current (A.C) techniques were investigated under standard conditions and electrolytically colored in sulfuric acid baths solutions at different operating conditions [Alternative Current density (A.C) (2-3) Amp/dm2, electrolyte concentration (2-6) Normality, electrolyte temperature (15-25) Co and anodizing time (20-60) minutes]. The experimental work was designed according to (Box-Wilson) method by using second order polynomial model between four variables and thickness of anodic layer for the two types of materials and substituted the experimental results for anodizing process in proposed model to calculate the coefficients of the mathematical equations to find an expression for obtaining best film thickness. The coloring deposition efficiency increases with the increase of applied electrolytic coloring alternative current and the purity of aluminum.
Under standard electrolytic coloring conditions, the current efficiency for coloring deposition is low for all examined materials. However, pure aluminum has much higher coloring deposition efficiency than the alloy. The anodizing alternative current density affects the electrolytic coloring process to a lesser degree for alloy than for pure aluminum, indicating the role of the morphology of the oxide film. The increases of anodizing temperature and porous layer thickness have marginal effect on electrolytic coloring process. Understanding the effect of alloy types on electrolytic coloring process will enable us to achieve color uniformity and to expand color and shade selections.

Erosion and dispersion of sandy soil with addition of fine materials

Ibrahaim M. Al-Kiki

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 470-483

For a better understanding of the performance of earth structures, it is essential to define and evaluate the variables that determine the erosion and dispersion of soils. A laboratory study has been carried out to characterize the soil internal erosion due to the water flow and the effect of fine materials percents on the erosion and dispersion of sandy soil.
A double hydrometer test, crumb test, slacking test and pinhole erosion test were conducted to investigate the soil dispersibility characteristics. Sandy soil samples were collected from a region in Mosul city – North of Iraq, and treated with different percents of fine materials of clayey soil, these percents were ranged from (0 – 80 %) of the dry weight of sandy soil.
The results showed that, the addition of fine materials enhanced both the compaction and dispersibility characteristics of sandy soil. As the fine materials increases, the soil resistance to internal erosion increased. So, the pinhole erosion test was the more reliability test to classify the soil according to the dispersibility.

Acoustic and Mechanical Properties of Polymer Composites Reinforced by Pre-Deformed Palm Fiber

Sihama I.Salih

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 484-499

This research was carried out to study the mechanical properties and thermal and acoustic insulation properties of prepared polymer composite. Petiole date palm fibers with the length (2-3mm) and with different volume fraction ratio (10, 20, 30 and 40%) were used as filler in preparation of polymer composite.
The research imply study effect of pre- deformation for petiole date palm fiber by chosen compression loads (0, 2, 4 and 6 MPa) on the mechanical properties as well as on the thermal and acoustic insulation properties of prepared composites. It was concluded that the pre-deformation to the fibers improves the thermal and acoustic insulation properties of prepared composite, as well as an increase in the tensile strength and hardness values with increasing compression load on the fibers. The highest values of the tensile strength and hardness reach to (133MPa) and (106) respectively for the polymer composite filled with 40% volume fraction of petiole date palm fibers which pre-deformed under compression load equal to 6 MPa.

Forward Kinematics Modeling of 5 DOF Stationary Articulated Robots

Tahseen Fadhil Abbas

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 500-512

This paper present a direct kinematics modeling of 5 DOF stationary articulated robot arm which is used for educational tasks, and presents an adopted modeling method to represent and simulate the simultaneous positional coordinates for each joint of the robot while it moving from one target to another, where a Lab Volt R5150 robot arm has been taken as a case study. the Denavite – Hartenberg (D-H) model of representation is used to model robot links and joints in this paper. It utilizes Matlab 2010a software as the tools for manipulation and testing. The adopted modeling solution was found to be identical with the physical behaviors.

Fabrication of Ceramic-Metal Functionally Graded Materials

Alaa A. Atiyah; Saad. B. H. Farid; Dheya N. Abdulamer

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 513-524

High order step wise functionally graded materials Al2O3-Ti are fabricated. These materials combine the high fracture toughness of Ti phase and the relatively low density of Al2O3 and stand for candidate materials for harsh mechanical and thermal environments. The techniques of powder technology are utilized to fabricate these materials that composed of five graded layers of Al2O3-Ti phases. Al2O3 increasing linearly across these layers (0, 25, 50, 75 and 100wt% respectively).
The green specimens are composed of Al2O3-TiH2 layers and the sintered specimens are composed of graded Al2O3-Ti. Spark Plasma Sintering technique is utilized for sintering of the graded green specimens. The best sintering conditions is found at 1500°C for 30 minute of sintering that gives apparent density of 4.25 g/cm3, porosity of 1.28% and diametric expansion of 1.58%. Optical microscopy shows gradual transition of phases at the interface of the graded layers

Detection of Failures in Alternator of Diesel Generator Based on theMicrocontroller Technique

Sadiq Kamel Gharkan

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 525-540

The goal of the present paper is to design and build electronic protection unit for detection of failures in alternator of diesel generator because of the many technical problems and failures or abnormal operating conditions that accompany the work of the generators when it used as a substitute for electrical energy, especially in long working hours.
Some of these problems and failures: increasing the temperature of the stator coils, loss of excitation, over/under frequency, over/under voltage and phase failure.
When any problem occur the proposal protection unit will be displayed the type of error or problem on liquid crystal display (LCD) as well as gives us an audio alarm and also shuts down the generator in critical situations.
The design was adopted mainly on microcontroller PIC16F877A, this design is characterized by low cost, uncomplicated, very high response and flexible to change software in case you need to add another failures without changing hardware if compared with the current protection unit in the original generators.

Pretreatment of Sawdust for Producing Sawdust Concrete

Haitham H. Saeed

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 541-549

Sawdust concrete has some shortcomings due to the harmful effects of some organic soluble components existing in the sawdust which affects setting and strength of sawdust concrete. Also, volume changes of sawdust as an aggregate due to variation of moisture content, cause large volume changes in the sawdust concrete. In this work, sawdust was treated before using as an aggregate for making sawdust concrete. The treatment included boiling the sawdust in water containing hydrated lime in order to dissolve all soluble organic components. To reduce water absorption of sawdust, it was dried and treated with waterproofing material. Two types of waterproofing materials were used (cutback asphalt and classic varnish). The properties of sawdust concrete were highly improved using pretreated sawdust. The increase of compressive strength was up to 50% for moderate sawdust ratios. Flexural strength is also increased, water absorption and thermal conductivity were highly reduced, while the basic advantages of sawdust concrete such as lightness of weight, sawability and nailability were not affected.

Design and Implementation of Optimal Multi-rate Digital Down Converter Using MALAB and ModelSim

Hazim Salah Abdalsatar

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 550-562

In this paper, a design and implementation of a digital down converter (DDC) filter for GSM, CDMA, WCDMA is presented. A powerful system design tool, Xilinx System Generator is adopted to simplify the design cycle and increase the productivity. The proposed DDC is composed of three stages of cascaded filters. The maximum operation speed of the Proposed DDC filter is 100MHz. The remaining sub-modules of the DDC, such as the FIR filter, is co-designed using MATLAB FDATool and ModelSim with a tradeoff between the receiving path of requirements, algorithm and hardware implementation complexity. The system has been successfully verified using the MATLAB module and ModelSim. The most important stage in the design is the HDL code generation for implementation phase and results verification.

Numerical and Experimental Analysis of the Bending Deflection of the Composite Beam

Mena Faisal Khdeer

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 563-572

This work studies the numerical and experimental bending deflection of 3-point test of the composite beam made of epoxy reinforced by glass fibers and carbon fibers at different volume fractions .The results show that the deflection decrease in nonlinear relationship with increase volume fraction for both glass fibers and carbon fibers .The maximum difference between the experimental results and the finite element results difference was (11 %) at load (=20 N) and fibers volume fraction (Vf= 10 %) for glass fibers reinforcement. Also the results indicated that the maximum deflection was (1.65mm) when reinforced by glass fibers at (Vf =10 %) and at load (= 20 N) experimentally, while the maximum value of deflection was (0.55mm) when reinforced at the same load and fibers volume fraction.

Design of On-Line Tuned Controller for Congestion Avoidance in Computer Networks

Saba T. Salim

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 573-584

Active Queue Management (AQM) applies a suitable control policy upon detecting congestion in networks. In this paper, a Proportional-Integral (PI) controller based on the optimization algorithm of MATLAB/Nonlinear Control Design Blockset (NCD) which is adapted as On-line tuning for controller parameters is applied to AQM for the objective of congestion avoidance and control in middle nodes. To present the methodology, a Proportional Integral (PI) controller is verified with the TCP/AQM model as an Active Queue Management (AQM) in internet routers The analytical results for linearized TCP/AQM model are presented in MATLAB/Simulink. From the obtained results, a faster response time as well as the regulation of the output to a constant value by the PI controller is clearly observed and it is noted that the PI controller based NCD provides good tracking performance for congestion avoidance in computer networks.

The Use of Gas-to-Liquid Technology (GTL) to Produce Gasoline and Diesel Fuels

Khalid A. Sukkar; Farah T. Jassm; Aswar A. Alwasiti; Muayad M. Hasan

Engineering and Technology Journal, 2013, Volume 31, Issue 3, Pages 585-598

The conversion of methane gas to synthesis gas (CO ‏ and H2) and then into clean liquid fuels via Fischer–Tropsch synthesis is investigated in the present work. The effects of the catalyst type, pretreatment conditions, and process temperature on the catalysts activity and selectivity are investigated.
The syngas production and Fischer–Tropsch synthesis were carried out in two catalytic units connected in series. The first one contains a fixed bed reactor of 128 cm3, while the second fixed bed reactor is of 68 cm3. The results of syngas production over the prepared (Pt/HY) catalyst showed excellent resistance to carbon deposition and stable performance during 20 h-on-stream at 700oC.
The Fischer–Tropsch synthesis was carried out under different temperatures of 220, 230, 240, 250, 260, and 270oC and constant atmospheric pressure. The results showed that the catalytic synthesis leads to a wide variety of products such as gasoline, diesel and waxes. It was concluded that the best operating temperature for all Fischer-Tropsch synthesis is 240oC, where, this temperature gives the highest hydrocarbons production for diesel and gasoline.
The results indicate that the Cu-Co/Al2O3 was the most active and selective catalyst in the Fischer-Tropsch process which gives the excellent production of the desired products.
In addition, this process shows a great potential for economical production of GTL fuels in Iraq at low costs.