Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 27, Issue 13

Volume 27, Issue 13, September 2009, Page 423-2522


FEM-Simulation of Single and Multi Layered Induction Heating Systems

Mohammed Moanes Ezzaldean Ali; Hanan A. R. Akkar; A. K. M. AL-Shaikhli

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2245-2262

Induction heating system has a number of inherent benefits compared to
traditional heating systems. Many analytical and numerical approaches have been applied to solve the problem of induction heating; efforts are made to introduce new development in computational approaches and utilization of newly developed specialized software packages to improve the methods of analysis and design of induction heating systems. This paper includes the description of the steps used for developing a general and comprehensive program, which works under ANSYS 11.0SP1 package environment. This program can be applied to analyze a wide
range of induction heating applications according to finite element method. Analysis approach is extended to deal with induction heating systems with magnetic material workpieces by introducing the multiregion method. Results of analysis the induction heating systems, by using ANSYS package, include all the electromagnetic and thermal quantities related to the induction heating process. To approve the simulation, used in this work, the results were compared with
published practical measurements, a good agreement was achieved.

Predictive Modeling of Hawiza Marsh Eutrophication

Ali K. Shayyish

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2263-2273

The term "eutrophic" refers to system rich in nutrients, and hence Eutrophication
means nutrient enrichment, particularly by increasing levels of nitrogen and
phosphorus [1]. In lakes, phosphorus is generally regarded as the limiting nutrient for
primary production [2] implying that increasing phosphorus concentrations will result
in increasing production of phytoplankton and benthic algae. Excessive amounts of
phytoplankton cause low Secchi depths and may consequently wipe out the benthic
flora by shading the light [3]. Toxic cyanobacteria tend to bloom when nutrient levels
are high [4]. Apart from being a nuisance in their own right, settling phytoplankton
may cause anoxia in hypolimnetic waters as their decomposition consumers oxygen
[5], and this may result in extinction of the benthic fauna [6] and fish feeding on such
animals. Altogether, these Eutrophication effects threaten the foundations of aquatic
ecosystems. The low oxygen levels in hypolimnetic waters associated with
Eutrophication may also cause mobilization of phosphorus in the sediments, thus
inducing a feedback mechanism where already high nutrient levels increase even more.

Contact Stresses for Different Gear Design Parameter

Muhsin J. Jweeg; Wisam Auday Hussain

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2274-2300

Gearing is one of the most critical components in mechanical power transmission
systems. This work investigates the characteristics of an Involute gear system
including contact stresses. Current methods of calculating spur gear (Non-linear
Analysis), contact stress using Hertz’s equation, which were originally derived for
contact between two cylinders. To enable the investigation of contact problems with
Finite Element Method (FEM), the stiffness relationship between the two contacts
areas is usually established through a spring placed between the two contacting areas.
This can be achieved by inserting a contact element placed in between the two areas
where contact occurs. A computer program was built up using (MATLAB 6.5). The
results of the two dimensional FEM analyses from ANSYS are presented. These
stresses are compared with the theoretical values (Hertz’s equations). Both results
agree very well. This indicates that the Finite Element Method(FEM) model is
accurate. The results of contact stress analysis indicates that increasing the geometrical
parameters (Pressure angle, number of teeth and module) lead to improve the tooth
contact stress, with the contact position, because the increasing of the geometrical
parameters will results in an increase of the tooth stiffness which leads to decrease the
tooth contact stress.

Detection of Rubidium (Rb85 & Rb87) ionized by Ultra-Violet light

Mohammed T. Hussein

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2301-2306

Photo-ions of rubidium were generated due to the interaction of effusive Rb
atomic beam with the C.W. UV lamp of 2.5 KW power. The photo-ions isotopic
of (Rb85 & Rb87 ) were extracted and analyzed by a quadruple mass filter. The
measured photo-ion current was 28 x 10-13 Amp.

Wedge Foundation in Expansive Soils

Mohammad A. Al-Neami; Farah S. Al-Jabary

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2307-2318

The object of this study is to find a construction solution to the problem of expansive soils by suggesting of a new shape of the conventional footing which has a sharp edge, this footing is named a “wedge footing” which is considered as an alternative shape to the strip footing to dissipate the swelling pressure produced in the soil when inserting the footing in it. These soils have a tendency
to absorb water and expand causing high damage to the lightly loaded buildings and structures. The analysis carried out using finite element method to assess the behaviour of displacement of the wedge footing compared with strip footing which is considered as a basic problem. An equation is obtained from the results of the computer package of “STATISTICA” based on the results of finite element analysis related to the displacement of wedge shaped footing as a function of soil properties and footing with coefficient of regression of (R2= 98.9%).

A Dynamic Modeling Capability for Subcritical Vapor Compression Refrigeration System

Jafar M. Hassan; Ali H. Tarrad; Mohammed N. Abdullah

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2319-2338

In this investigation the individual component models for a typical subcritical cycle are developed based on the best published theoretical and empirical literature. The developed approach, especially for air conditioning systems, is conceptually new and can be used with modification to a variety of multicomponent system applications. The component models are then integrated and the model predictions validated against the data from various experimental test systems.
A variable speed compressor test rig was used to obtain the experimental data to be compared with the results predicted from the system model. The experimental data was monitored from the start-up of the system until the achievement of its steady-state. The system approached its steady-state after 270 sec and 360 sec for compressor speeds of 900 rpm and 1200 rpm respectively. The system disturbance was imposed by changing the operation conditions for each component. A comparison between the experimental data for these disturbances and theoretical results shows a good agreement with a discrepancy of
about (5%). The model can be used as a basis for the design, performance and efficiency of a vapor compression systems.

Finite Element Analysis Up To Failure Of Composite Concrete – Corrugated Steel Cylindrical Shells

Ahmed T. Mahdi; Eyad K. Sayhood; Husain M. Husain

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2339-2351

This study presents three-dimensional finite element analysis to the behavior of composite concrete-corrugated steel cylindrical shell. This type of construction utilizes the advantages of both of ordinary reinforced concrete and the composite action of cylindrical shell with corrugated steel plates. The 8-node brick elements in (ANSYS v.9.0) have been used to represent the concrete, while the steel bars
are modeled as discrete axial members connected with concrete elements at shared nodes with the assumption of prefect bond between the concrete and the steel bars. The corrugated steel plate is modeled by four-node shell elements. The interface elements are modeled by using three-dimensional surface to surface contact elements connected with the nodes of concrete and steel channel elements. Comparison is made between the results obtained from the finite element analysis and the available experimental results of previous studies

Encrypting Audio Data Hiding by Visual Secret Sharing

Nidaa F. Hassan; Rehab F. Hassan; Akbas E. Ali

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2352-2364

Steganography and cryptography are usually used to ensure information
safety in today’s data communication. This paper makes use of audio
steganography technique and encrypted secret sharing to increases the security level of hidden data. The proposed schema can hide digital data in audio file; the resulted stego audio file is separated then into 2- shares encrypted random secure images, which can be transmitted or distributed separately over an threaten communication channel. Using multilevel of security techniques increases the security level of hidden data, and makes it more robust to attack since secret data
is not hidden in one cover media but it is separated across two images, that they will be encrypted and appear completely random.

Simulation of Spontaneous Condensation of Viscous SteamFlow in Low-Pressure Convergent-Divergent Nozzles

Assim H Yousif; Kassim K Abbas; Aqeel M Jary

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2365-2392

The present study describes the results of experimental and numerical investigation of wet steam flow in low-pressure convergent-divergent nozzles and deals with the effects of turbulence on the process of homogeneous condensation. The experimental investigation consist mainly the axial pressure distribution of a fixed nozzle test section. The mathematical model that described the droplet nucleation and the growth rates combined with the field conservations was treated numerically within the CFD code FLUENT 6.3., in which the computational domain is discretized in a general unstructured mesh that is locally refined
especially in the area of the spontaneous nucleation zone. The equations describing droplet formations and interphase change are solved sequentially after solving the main flow conservation equations. The calculations were carried out assuming that the flow is twodimensional, compressible, turbulent and viscous. The aimof the present study is the use of the modified k-ε model for modeling the turbulence within an unstructured mesh solver. The results obtained from the numerical part of the current analysis are compared with the
experimental results and gave an acceptable agreement. Also present experimental and numerical results showed good agreements with numerical and experimental existing published data.

Performance of Fiber Light-Weight Aggregate Concrete Exposed to Elevated Temperatures

Shakir A. Salih; Ali T. Jasim

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2393-2410

Two major problems arise when concrete is exposed to elevated
temperatures. One is the deterioration in mechanical properties of concrete and the other problem is spalling of concrete. In recent times, the inclusion of polypropylene fibers had been reported to be a feasible method to prevent spalling of concrete subjected to elevated temperature. Additional problems arise due to the fact that by adding polypropylene fibers, the residual properties of heated concrete
may be adversely affected. The essential objective of this work is to investigate the effect of incorporation of polypropylene fibers or/and steel fibers on the residual properties of lightweight concrete made from porcelinite aggregate after subjected to elevated temperatures. The concrete specimens heated to target temperatures of 100, 200, 400, 600 and 800 oC, at a rate of 10 oC per minute. When the target
temperature was reached, the specimens were kept at that temperature for 2 hours and then allowed to cool to room temperature by natural cooling. For each type of concrete, compressive strength, splitting tensile strength, static modulus of elasticity, and thermal expansion strains were determined before and after exposing the concrete to the target elevated temperatures. Experimental results indicated that
polypropylene fiber-reinforced LWAC showed more reduction in its residual mechanical properties compared to plain LWAC. These different are more pronounced at exposure temperature of 200 and 400 oC. Average differences of 30,25 and 20 percent were observed in static modulus of elasticity, splitting tensile strength and compressive strength respectively, for specimens heated up to 400 oC. The addition of steel fibers inside the polypropylene fiber concrete would improve
the residual mechanical properties of heated concrete at temperature range 200 to 600 oC. On average, the improvement ranged from 9 to 20 percent.

Live Load Distribution for Steel-Girder Bridges

Ammar A. Ali

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2411-2428

Grillage method is used here to determine girder distribution factor (GDF). STAAD Pro. 2006 program is used here to represent grillage and solving for (GDF). Different GDFs are adopted by AASHTO LRFD based on the National Cooperative Highway Research Program (NCHRP) 12-26 and the results compared with formulas given by AASHTO Standard. Three different composite steel bridge superstructures are considered with girder spacing (1.22, 2.44 and 3.66 m). To compute GDF in the
considered bridges subjected to one truck, the vehicle is placed on each bridge such that the load effect in the girders is maximized. If compared with Finite element method, the modified grillage was found to be simple, efficient and having practical accuracy in the analysis of bridge decks in determining GDF factors.

Improvement of the Performance of OCDMA By Using Error Correction Code

Hosham Salim; JafarM. Daif

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2429-2447

In this paper a new approach is proposed for enhancement of the data
transmission optical communication systems by applying CDMA technique based error detection and correction code. This paper includes the study and analysis of the different important variables for optical CDMA system, and focuses on increasing the system performance by selecting the optimum values for different variables to reduce the multiple access interference problems and also by applying error detection and correction code with selecting of the best polynomial. The
detected and corrected code technique is more active because the selection of the optimum values from the variables network helps to decrease the interference sources and noise to lower value. The selection of optimum values helps in reducing the number of the added correct bits in the transmit code word consequence enhancement of the system performance because the channel is exploited to transmit the information. The results show enhancement in system performance when selecting optimum value of received power (2μ Watt), where the enhancement ratio is equal to (23%). Also this paper proves the use of error correction technique became very active with the optimum values of received power (2 μWatt), so the improvement ratio with applying ECC is equal to (22%).

Prediction of Tigris River Stage in Qurna, South of Iraq, Using Artificial Neural Networks

Ali H. Al Aboodi; Ammar S. Dawood; Sarmad A. Abbas

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2448-2456

Artificial neural networks (ANNs) with back-propagation algorithm are
performed for predicting the stage of Tigris River in Qurna city, Basrah, south of Iraq. This model was adopted to investigate the applicability of ANNs as an effective tool to simulate the river stage for short term. By using the neural network toolbox in Matlab R2007b, three models are constructed as the first experiment. Multilayer percpetron with one hidden layer is used in the architecture of network. The best model is selected according to the trial and error
procedure based on three common statistic coefficients (coefficient of correlation, root mean square error, and coefficient of efficiency). The best model from first experiment is used to predict the stage river for one, two, and three days ahead as the second experiment. Results indicated the ANNs with back-propagation algorithm are a powerful technique to predict the short term stage of Tigris River

Enhancing Embedded Data Security By Turns Cipher Block Chaining Mode Into Stream Cipher

Salah Mahdi Saleh

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2457-2473

In this paper, a secure data hiding method is introduced. It increases the security of embedded data through combining between the steganography and cryptography. First, the secrete message is divided into blocks with same size according to length of key stream that is generated using nonlinear key generator. This key is used to encrypt the first block in secret message using the stream cipher, whereas the other blocks are encrypted depending on the behavior of cipher block chaining (CBC) mode that turn on the stream cipher in order to
guarantee no duplicated encrypted blocks. In our CBC mode the current ciphertext block will became a key stream to encrypt the next plaintext block, and so on. After encryption stage complete, the encrypted massage are embedded randomly in bmp image using LSB insertion method to increase the security.

Design a Position Control of the Blade Pitch Angle for Variable Speed Wind Turbine Generators

Roshen T. Ahmed

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2474-2488

Variable speed wind turbine generators are more powerful than constant
speed turbines. However the unstable wind speed causes the variable speed machine to have variable voltage and frequency. The quality of power can be improved if a suitable control technique is used
in the system, the fluctuating wind generator output needs to be controlled, for this reason one needs to study the dynamic characteristics of the combined wind generator system. Better control design can be designed for more dynamic performance. Blade pitch control of the fan is discussed here in this research by using rotary
potentiometers for position control and some tests is done in control laboratory as a simulation of the position control.

A Practical Method for Production of Foamed Glass

Aseel B. Al-Zubaidi

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2489-2495

A two stage preparation method of foamed glass is described here aiming
to achieve reproducibility and convenience. Fritting of the solid components assembles the first stage; where firing a mix of the frit, foaming agents and the liquid component gather the second stage. Almost uniform cellular structure of the foamed glass is achieved at elatively low firing temperature of the mix (820°C for 10 min). The cellular structure is enclosed with a shell of continuous surface. Physical properties (density, porosity and water absorption) are measured
for the product along with the mechanical properties that concerns production of building blocks, namely impact and compression strength.
The flexibility of the presented two stage preparation method simplifies
future attempts to modify its properties to adapt particular applications.

Improvement of Output Displacement of Servo Pneumatic System using Fuzzy PI Controller

Mohammed Y. Hassan; Majid A. Oleiwi; Shaimaa Mahmood Mahdy

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2496-2508

Pneumatic systems are widely used in industrial automation for their
advantages such as speed of motion, low cost of maintenance, safe operation and high power/ weight ratio, cleanliness, simplicity of operation as compared with other systems such as hydraulic and electro - mechanical technologies. In this work, a fuzzy PI controller is designed for improving the output displacement of the servo pneumatic system, in order to improve the position transient response. The aim of tuning is to reach minimum steady state error in the output displacement and also to compensate the effect of applying
different types of external load forces. The parameters of the controller are tuned using a trial and error method. A comparison between the results of using Fuzzy PI controller and the PID controller showed that the Fuzzy PI controller has improved the maximum error ratio in position up to 45 % by adding a fixed external load force and up to 19 % by adding variable external load force with high
compensation for the effects of any external load force.

Analysis Up To Failure of Straight and Horizontally Curved Composite Precast Beam and Cast-In-Place Slab with Partial Interaction

Husain M. Husain; Mohammed J. Hamood; Shaima; a Tariq Sakin

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 2509-2522

In this study, a nonlinear three dimensional finite element analysis has been used to conduct an analytical investigation on the behavior of curved in plan composite concrete-concrete beam using the analysis system computer program (ANSYS v.9.0 2004). Various types of beams, with available experimental results are chosen to check the validity and the accuracy of the adopted models. In general good agreement is obtained. The maximum percentage difference in ultimate loadcarrying
capacity is 12%. Parametric studies are carried out to study the influence of the curvature (L/R ratio of 0, 0.1, 0.15 and 0.2) on the behavior of the curved in plan composite concrete beams. Also, some important material and solution parameters that affect the structure behavior are studied. These include the slab thickness, support condition, compressive strength of concrete and the percentage
of steel across the interface between the stem and the slab of the composite beam.

Effect of Dual Reinforcement on Wear Resistance by Aluminum Compacts Reinforce by SiC, Al2O3

Mohammed Moanes Ezzaldean Ali; Hanan A. R. Akkar; A. K. M. AL-Shaikhli; Ali K. Shayyish; Muhsin J. Jweeg; Wisam Auday Hussain; Mohammed T. Hussein; Mohammad A. Al-Neami; Farah S. Al-Jabary; Jafar M. Hassan; Ali H. Tarrad; Mohammed N. Abdullah; Ahmed T. Mahdi; Eyad K. Sayhood; Husain M. Husain; Nidaa F. Hassan; Rehab F. Hassan; Akbas E. Ali; Assim H Yousif; Kassim K Abbas; Aqeel M Jary; Shakir A. Salih; Ali T. Jasim; Ammar A. Ali; Hosham Salim; JafarM. Daif; Ali H. Al Aboodi; Ammar S. Dawood; Sarmad A. Abbas; Salah Mahdi Saleh; Roshen T. Ahmed; Aseel B. Al-Zubaidi; Mohammed Y. Hassan; Majid A. Oleiwi; Shaimaa Mahmood Mahdy; Husain M. Husain; Mohammed J. Hamood; Shaima; a Tariq Sakin

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 423-429

The producing composite materials of dual reinforcement in which the matrix material is aluminum reinforced with two types of ceramic particles : which are Alumina (50μm

Keywords

composite materials; wear test ; Al2O3; SiC: Al

Effect of Non-Symmetric Die on Extrusion Process And Product Bending

Engineering and Technology Journal, 2009, Volume 27, Issue 13, Pages 430-450

The development in production of curved sections in one forming process
using direct extrusion process is going to increase annually because of increasing demands on such sections that are used in car body construction and railways .This research aims to find a new method for design of non-symmetric dies ,that can extrude a curved product by one pass of extrusion and by controlling the material flow through the deformation zone of the die .The (F.E.M) and (U.B.M) were used in
designing the non-symmetric dies so that the lower and upper die angles are different. The simulation of metal flow during the extrusion process, stresses and strains distribution in the bullet, friction factor and the die angles on the bending or eccentricity of the product were found. The extrusion pressure and the power consumption during the process were also found using both (FEM) and (UBM) methods. The results have shown that :
The bend of the product using non-symmetric dies is always towards the small die angle. It has been also shown that the amount of bent or the eccentricity of the product can be predicted from the extrusion parameters. The amount of eccentricity increased with increases of the metal displacement in the dies.