Hassan Hamed Abd Al-Hachami
Volume 4, Issue 2 , June 2011, Pages 0-0
Abstract
In This Work ,The producing composite materials to types of ceramic particles : by Die Compaction method and Samples prepared and fired at ( 1100 0C ). It is measuring Physical properties after use different Parameters such (different pressing pressure and Zirconia has been added with different) ...
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In This Work ,The producing composite materials to types of ceramic particles : by Die Compaction method and Samples prepared and fired at ( 1100 0C ). It is measuring Physical properties after use different Parameters such (different pressing pressure and Zirconia has been added with different) By showed the increased the physical properties bulk density, apparent density whith increased Zirconia by method linear becuse higher density material Zirconia )6 gm/cm3(.
Volume 4, Issue 2 , June 2011, Pages 0-0
Abstract
A construction industry has a special characters, differs from the other industries; becomes of its huge size, continuous build up and the dependency of the others projects on it ( i.e projects builds needs constructions) and it can be argued that the construction industry, an industry productive
To ...
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A construction industry has a special characters, differs from the other industries; becomes of its huge size, continuous build up and the dependency of the others projects on it ( i.e projects builds needs constructions) and it can be argued that the construction industry, an industry productive
To any successful project implementation it needed to consider all the integration between project phases.Any defect in the application of the project time schedule will tend to extra costs, delay fines and this will cause a loss of profit national economy because of the delay in the project commissioning time schedule and taking advantage of this project.
The aims of this research are to study and analyze the defect in the time control system for projects construction. To get the objectives of the search, the researchers use to study previous literatures rummages deals with project time scheduling and control. In this study Cairo-UR Bridge project was selected for monitoring and follow up.
We collecting and analysis the data to determine the deviation in the project time schedule. In this study we discussed a number of solutions to decline this deviation by adoption of scientific methods after the application of these solutions this deviation was decline but not completely disappear for many reasons, we explained it during this study.
Ehsan Sabah M. Al-Ameen
Volume 4, Issue 2 , June 2011, Pages 1-8
Abstract
The effect of drilled and moulded-in circular holes of woven fabric composites on failure strength have been examined in flexural test. Three types of woven fabric-reinforced composite systems were used: glass fiber (E glass), Kevlar fiber, and glass- Kevlar hybrid in polyester matrix. All these types ...
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The effect of drilled and moulded-in circular holes of woven fabric composites on failure strength have been examined in flexural test. Three types of woven fabric-reinforced composite systems were used: glass fiber (E glass), Kevlar fiber, and glass- Kevlar hybrid in polyester matrix. All these types are of (30%) volume fraction, and hole diameter of (1, 2, 3, 4 and 5 mm) for each type. ISO standard flexural specimens were tested and repeated three times.
It is noticed that the specimens with moulded-in holes exhibit failure strengths higher than those of drilled specimens by (7- 24%). Also the values of stress concentration factors (Kt) increase with increasing the hole size for all types of laminates, and they were arranged in an ascending order as follows: Kevlar/ polyester, glass-kevlar hybrid/ polyester, and glass/ polyester.
Haider Khazal Mehbes; Hassanein Ibraheem Khalaf; Ameen Ahmad Nassar
Volume 4, Issue 2 , June 2011, Pages 9-25
Abstract
This paper presents an efficient meshless method by using an elliptic domain rather than traditional isotropic domain of influence. The method involves an element free Galerkin formulation in conjunction with an anisotropic weight function. In the elliptic weight function, each node has three characteristic ...
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This paper presents an efficient meshless method by using an elliptic domain rather than traditional isotropic domain of influence. The method involves an element free Galerkin formulation in conjunction with an anisotropic weight function. In the elliptic weight function, each node has three characteristic indications that are major radius, inner radius, and the direction of the local domain. Furthermore, the space that will be covered by the elliptic will be less than the area of the circle (isotropic) at the same main diameter. This means leaving many points of integration are not necessary. Therefore, the computational cost was decreased. For the first time, the elliptic domain is used in the problems of linear elastic fracture mechanism LEFM. MATLAB codes are used in obtaining the results of this research. The results are compared with those present in the literature.
Dr. Fadhel Abbas Abdullah
Volume 4, Issue 2 , June 2011, Pages 26-36
Abstract
Theoretical and experimental investigations of composite material as thermal insulation consists of natural fibers (White feather, Jute, Egg shell, and Black feather) are present in this work. The experimental works are divided into two parts. The first part involved with the study of the thermal conductivity ...
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Theoretical and experimental investigations of composite material as thermal insulation consists of natural fibers (White feather, Jute, Egg shell, and Black feather) are present in this work. The experimental works are divided into two parts. The first part involved with the study of the thermal conductivity of the composite materials. Lee's disc method is used to measure the thermal conductivity of different types of natural composite materials. These values are compared with theoretical values of thermal conductivity calculated using Maxwell model. The effect of volume fraction on thermal conductivity is studied. The second part included building two rigs which have the dimensions (1m X 1m X 1m). The first rig used as reference and the second rig to measure the temperature distribution on the lower surface of the roof insulation. The effects of change in volume fraction, air gap, and types of natural composite insulation on temperature reduction are investigated. The results show that the (Jute composite material) gives good results as composite thermal insulation compared with other natural composite materials.
Hassanain Ghani Hameed; Hayder Aziz Neema
Volume 4, Issue 2 , June 2011, Pages 37-50
Abstract
In this research a parabolic solar concentrator system has been experimentally studied. The experimental devise consists of a communication satellite dish with 1.5 m diameter and 0.17 m depth. Its interior surface is covered with aluminum reflecting layer and equipped with a disc receiver, (with diameter ...
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In this research a parabolic solar concentrator system has been experimentally studied. The experimental devise consists of a communication satellite dish with 1.5 m diameter and 0.17 m depth. Its interior surface is covered with aluminum reflecting layer and equipped with a disc receiver, (with diameter of 0.22 m and depth of 0.07 m) in its focal position. The orientation of the dish is assured by the tracking system for the satellite, as a tracking system for the sun, with some limitations. Performance of the solar evaporating system is tested under the local conditions of Najaf city during the interval from 10/3 to 25/4/2010. The data are collected on ambient temperature, temperature of inflow water, water and vapor temperatures inside the receiver. The obtained results showed that the amount of distillate was much dependent on the incident solar radiation intensity and the accurate focusing of the system. The system productivity can range from 6.9 to 15.3 L/day of fresh water, when the air was used to condensate the vapor receiver output (air – cooling), and this productivity increased by 28 – 33.5% when the inflow water used to condensate the vapor receiver output (water – cooling).
Abdul Munium Razoki Majeed Algbory
Volume 4, Issue 2 , June 2011, Pages 51-67
Abstract
In this study, the stress analsis of the steel-aluminum compound thick cylinders under the effects of internal pressure, thermal loading and rotational loading has been carried out using the finite element method. The structure is treated as axisymmetric body, because each of the geometry and applied ...
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In this study, the stress analsis of the steel-aluminum compound thick cylinders under the effects of internal pressure, thermal loading and rotational loading has been carried out using the finite element method. The structure is treated as axisymmetric body, because each of the geometry and applied loads are symmetric about the longitudinal axis.
The stresses variations (Hoop, Axial, Radial, Equivalent) through the walls thickness are determine here and the results were checked using two theories of elastic failures (Tresca and Von-Misses).
The results showed that, the Hoop stresses at the inner surface is about (600 MPa) due to effect of Internal pressure, (-500 MPa) due to thermal load, (57 MPa) due to effect of rotational speed while about (150 MPa) due to the effect of the total loading.
It can be seen that the max. hoop stress concentrated at the contact surface between the two cylinders. Also the temperature distribution through the cylinder thickness has been determined.
Dr. Gazi K. Saeed; Dr. Saad B. H. Farid; Dr. Fadhil A. Chyad
Volume 4, Issue 2 , June 2011, Pages 68-74
Abstract
Four varieties of sodium feldspar substitutes have been prepared. Different percentages of kaolin, silica and sodium salts are milled, mixed and submitted to heat treatment. The reacted powders are then grinded and tested by x-ray diffraction. The results show the existence of feldspar phase. The densities ...
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Four varieties of sodium feldspar substitutes have been prepared. Different percentages of kaolin, silica and sodium salts are milled, mixed and submitted to heat treatment. The reacted powders are then grinded and tested by x-ray diffraction. The results show the existence of feldspar phase. The densities were measured and show close agreement to the reported values. The final result is establishing a technological root for the synthesis of feldspar substitute utilizing local materials.
Musa H. Waly; Emad A. Hussein
Volume 4, Issue 2 , June 2011, Pages 75-92
Abstract
The selection of the three coefficients of proportional-integral (PID) controllers (Ki, Kp, and Kd) is basically a search problem in a three-dimensional space. This is so because points in the search space correspond to different selections of a PID controller’s three parameters. By choosing different ...
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The selection of the three coefficients of proportional-integral (PID) controllers (Ki, Kp, and Kd) is basically a search problem in a three-dimensional space. This is so because points in the search space correspond to different selections of a PID controller’s three parameters. By choosing different points of parameter space, we can produce, for example, different step responses for a step input. A PID controller can be determined by moving in this search space on trial-and-error basis. The main problem in the selection of the three coefficients is that these coefficients do not readily translate into the desired performance and robustness characteristics that the control system designer has in mind. Several rules and methods using root locus and performance indices. The first design uses the Integral of Time multiplied by Absolute Error (ITAE) performance index. Hence we select the three PID coefficients (Ki, Kp, and Kd) to minimize the ITAE performance index, which produces a good transient response to a step input.
Our paper uses the Genetic Algorithm (GA). In this method the selection of the three PID coefficients depends on the minimization of the Mean Squared Error (MSE), which will produce an excellent transient response to a step input.
Wasan A. Jehad; Yaqeen S. Mezaal
Volume 4, Issue 2 , June 2011, Pages 93-100
Abstract
A novel design for compact microstrip bandpass filter design is presented for use in the application of modern wireless communication systems. The proposed filter structure is composed of two fractal-based microstrip resonators. The structure of each resonator is in the form of the Peano fractal curve ...
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A novel design for compact microstrip bandpass filter design is presented for use in the application of modern wireless communication systems. The proposed filter structure is composed of two fractal-based microstrip resonators. The structure of each resonator is in the form of the Peano fractal curve geometry. Two microstrip single-mode resonators with structures based on the 2nd Peano fractal-shaped geometries have been modeled at a design frequency of 2.4 GHz. The resulting filter structures based on these resonators, show considerable size reduction compared with the other microstrip bandpass filters based on other space-filling geometries designed at the same frequency. The performance of the resulting filter structures has been evaluated using a method of moments (MoM) based software package, Microwave Office 2009, from Advanced Wave Research Inc. Results show that the proposed filter structures possess good return loss and transmission responses besides the size reduction gained, making them suitable for use in a wide variety of wireless communication applications. Furthermore, performance responses show that the new resonator has less tendency to support the higher harmonics.
Dr. HANAN A. R. AKKAR
Volume 4, Issue 2 , June 2011, Pages 101-111
Abstract
The structure is a very important aspect in neural network design, it is not only impossible to determine an optimal structure for a given problem, it is even impossible to prove that a given structure is optimal. In this paper, PSO (Particle Swarm Optimization) are used to construct best ANN (Artificial ...
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The structure is a very important aspect in neural network design, it is not only impossible to determine an optimal structure for a given problem, it is even impossible to prove that a given structure is optimal. In this paper, PSO (Particle Swarm Optimization) are used to construct best ANN (Artificial Neural Network) architectures, and find an optimal pattern of connections and weights to reduce structure complexity by minimizing the number of connection weights in a Feed Forward Artificial Neural Network (FFANN). They are called Particle Swarm Optimization-Neural Network systems (PSONN). PSONN systems are examined through theoretical analysis and computer simulation using MATLAB package. They are tested by several different examples, where the tests show that PSO a more efficient and automated search method can be used to find an optimal topology of ANN. The best and trained network with few numbers of iteration is provided using PSONN for finding an optimal structure. Finally, a simpler network, faster training with higher accuracy than full connected network is obtained by using PSONN for finding optimal connections and weights.
Yahya Jasim Harbi
Volume 4, Issue 2 , June 2011, Pages 112-121
Abstract
Channel coding is very important for secure communication. The most widely used communication coding is turbo coding technique, which is very secure technique. We deal in this paper with turbo code which is new class of convolutional codes. The performance of turbo code reaches the Shanon limits in terms ...
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Channel coding is very important for secure communication. The most widely used communication coding is turbo coding technique, which is very secure technique. We deal in this paper with turbo code which is new class of convolutional codes. The performance of turbo code reaches the Shanon limits in terms of bit error rate BER. To build the turbo code encoder we used two parallel concatinations of two Recursive Systematic Convolutional codes (RSC) and the associated decoder which is using the feedback decoding rule. At low signal-to-noise ratio (SNR), bit error rates (BER) of Turbo code were obtained by simulation.
Fadhil A. Hassan; Ola Hussian; Dr. Majid K. Al-Khatat
Volume 4, Issue 2 , June 2011, Pages 122-133
Abstract
This paper proposes a new simplified method for design, simulation, implementation, and obtaining optimum value of ac output filter to the SVPWM inverter fed induction motor using the benefit of PSIM program is developed. Also a complex mathematical equations and transfer functions are not desirable.
...
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This paper proposes a new simplified method for design, simulation, implementation, and obtaining optimum value of ac output filter to the SVPWM inverter fed induction motor using the benefit of PSIM program is developed. Also a complex mathematical equations and transfer functions are not desirable.
The L-C filter cancels all harmonics and a real pure sinusoidal output voltage and current is obtained. Due to the flexibility of PSIM software, the values of L-C combination are obtained by trial and error method. The advantage of this method, it can vary the values of inductor and capacitor until the value of desired outcome is obtained.
Experimental and simulation results have verified the superior performance and the effectiveness in reduction the harmonics of the proposed filter.
Giath A. Al-Sharify
Volume 4, Issue 2 , June 2011, Pages 134-142
Abstract
The chemical additives are one of the most common solutions to stabilize expansive clay. Microsilica is one of these additives used recently to improve the engineering properties of soft and plastic clay. This study investigates the suitability of such additive to improve the swelling characteristics. ...
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The chemical additives are one of the most common solutions to stabilize expansive clay. Microsilica is one of these additives used recently to improve the engineering properties of soft and plastic clay. This study investigates the suitability of such additive to improve the swelling characteristics. Moreover, two cases will be examined; the effect of adding (0 - 10) percentages of the microsilica alone and the microsilica in conjunction with lime. The results indicate that, the microsilica has a positive effect on the swelling characteristics especially in the presence of lime. The percent of free swell and swell pressure decreased 24.49% and 34.64% respectively due to adding up to 10% of microsilica. This reduction becomes 53.94% for free swell and 59.75% for swell pressure when added in the presence of 2% of lime. Moreover, approximately 85% of this reduction has been achieved at 4 % of microsilica and 2 % of lime.
Zaidun Naji Abudi
Volume 4, Issue 2 , June 2011, Pages 143-155
Abstract
The specific goals of this study are to determine the optimum inflow to the filters (hydraulic loading rates) and media characteristic such as the effective size, the particle size distributions within the bed media. In addition to modify the traditional slow sand filter to gain better flow control to ...
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The specific goals of this study are to determine the optimum inflow to the filters (hydraulic loading rates) and media characteristic such as the effective size, the particle size distributions within the bed media. In addition to modify the traditional slow sand filter to gain better flow control to treat grey water of high turbidity. Three set of experiments were carried out during nine months from April to December in Mustansiryiah University, college of engineering, environmental hydraulic laboratory.
The first set of experiments were achieved by using (1m height) sand of effective diameter 0.35 mm, uniformity coefficient, UC=2.2 and porosity (39%), the second set of experiments were carried out by using sand of 0.75mm diameter, UC= 2.9 and porosity (43%) to study the effect of grain size of sand on water head over sand surface and removal efficiency. While the other set of experiments were done by using (0.7m height) sand of effective diameter 0.35 mm, UC=2.2 and porosity (39%) to study the effect of filter height of sand on removal efficiency.
Measurements of chemical, physical and bacterial parameters were achieved during nine months from April to December. These parameters include turbidity, pH, PO4-2, BOD5, COD, TDS, TSS, and coliform removal for treated grey water.
Results show that filter loading rate has been determined to be not more than 680 L/hr/m2 which removal efficiency of BOD5 was (51%) and minimum filter loading rate has been tested to be 212 L/hr/m2 which removal efficiency of BOD5 was (83%).
Khamail Abdul-Mahdi Mosheer
Volume 4, Issue 2 , June 2011, Pages 156-167
Abstract
The primary objective is to determine whether the structural efficiency of plates can be improved with variable thickness. The large displacement analysis of steel plate with variable thickness at x-direction is obtained numerically, using finite differences. The effects of boundary condition, tapering ...
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The primary objective is to determine whether the structural efficiency of plates can be improved with variable thickness. The large displacement analysis of steel plate with variable thickness at x-direction is obtained numerically, using finite differences. The effects of boundary condition, tapering ratio, type of tapering equation and plate aspect ratio on large deflection behavior of rectangular plates are investigated. Numerical results for rectangular steel plate are presented for the different effects. This study showed that the large deflection behavior is very sensitive for thickness variation (tapering ratio) where the maximum deflection will increase about 5% for slenderness ratio (b/t=100) and tapering ratio (1-2) of simply supported plate.
