ISSN: 1999-8716

Volume 4, Issue 1

Volume 4, Issue 1, Spring 2011, Page 1-143


MODELING OF THE CURE OF EPOXY BASED COMPOSITE, HEATED AT CONSTANT TEMPERATURE IN CYLINDERICAL MOULD

Adnan A. Abdul Razak

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 1-11

ABSTRACT:- The heat transfer process involved in the curing of fiber-reinforced thermosetting composites is investigated numerically. This composite is made of woven fiber and resin and placed in a cylindrical mould. The governing equation for one dimensional heat transfer, and accounting for the heat generation due to the exothermic cure reaction in the composites had been used. A finite element method is developed to solve the mathematical model problems for composites manufacturing. The solution of the complete mathematical system gives, both, the temperature and the degree of reaction as functions of time and position. It was found that the temperature at the central of the sample increases up to the external imposed temperature, because of the thermal conductivity of the resin and fiber. The heat generated by the exothermic reaction of the resin is not adequately removed; the increase in the temperature at the center increases the resins rate reaction, which in turn generates more heat.
Keywords:- Mathematical model, curing, epoxy resin, cylindrical mould

FROM A HORIZONTAL CYLINDER EMBEDDED IN A POROUS MEDIA

Ahmed Hassen Ahmed; Eklas Edan Kader; Hatam Abd Hassan; Abdulrakib Abdulwahab Masad Al-Wahbi; Omer Hazem Karofa; Manar Salih Mahdi; Safa Hussain Abid Awn; Osama Y. AL-Rawi; Ali H. Aziz; Saad Qassim Fleh; Ali Laftah Abbas

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 1-19

ABSTRACT:- Theoretical and experimental study of heat transfer steady natural convection from the cylinder embedded in a saturated porous media was cared out. the theoretical part of the work includes the derivation of the governing momentum and energy equation by using Darcy flow model. The two equations are solved by finite difference method with constant cylinder surface temperature, with a Peclet number under steady condition and Rayleigh number ranged between (10

Keywords

natural convection
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porous media
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horizontal cylinder
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الحمل الطبيعي
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الوسط المسامي
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اسطوانة أفقية.

ELASTIC- PLASTIC ANALYSIS FOR SQUARE SHELL TUBES DURING PURE BENDING USING FINITE ELEMENT

Eklas Edan Kader

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 12-29

ABSTRACT :- An analytical model with sufficiently non linear kinematics to capture the development in engineering applications to resist bending stress for thin walled elastic-plastic steel tubes which used as structural members. The results indicate that collapse of such tubes is imperfection sensitive for tubes with height to thickness ratio (h/t), but the sensitivity decreases as the ratio decreases. Experimentally, the tubes collapse due a limit moment instability which is followed by the formation of a kink on the compression flange of the tubes. The present research removes the limitation in the pre- bifurcation analysis and concentrates on the numerical prediction ANSYS -11 program of the response with stress and strain distribution on thin walled tubes of square cross section. The numerical, analytical and experimental results are converges to each other, by simulating the response of square tubes subjected to static and dynamic axial bending loading .The finite element models used for this work are featured by the geo-metric and material characteristics of square tubes and comparison of the computed bending response to the results and findings of the experimental works shows that the finite element models described here, approached the actual bending response of the square tubes to a satisfactory degree both in terms of collapse modes and main bending characteristics such as bending stress and strain and deformation displacement.
Keywords:- Finite element model, square shell, bending.

STUDY EFFECTIVE OF HARDENING BY BAD OIL ENGINE AND TEMPERING TO SOME MECHANICAL PROPERTIES

Hatam Abd Hassan

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 20-30

ABSTRACT:- This research aims to develop some mechanical properties for carbon steel (CK38) ductility ,yield stress ,shear stress ,ultimate stress ,fracture stress and impact strength ) at quenching (15) samples testing for every tensile and intact tests in dissociated engine oil medium with circulating and tempering at 260 oC , 460 oC and 650 oC temperature) , ( 3) samples testing for every tempering temperature) , (5) for hardness and one for chemicals composition . then compare mechanical properties before and after heat treatment to show if we can use it in much and important The results after heat treatment show increase in ductility ,yield stress ,shear stress ,ultimate stress ,fracture stress ,impact strength , static and dynamic energy .

REMOVAL OF METHYLENE BLUE FROM AQUEOUS SOLUTIONS USING YEMEN BENTONITE

Abdulrakib Abdulwahab Masad Al-Wahbi

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 30-53

ABSTRACT - Removal of Methylene Blue (MB) from aqueous solutions using Yemen bentonite as low-cost adsorbent have been studied as a function of temperature, particle size and solution pH . The adsorption capacity increased with increasing temperature (15 to 45˚C ) and solution pH value (2 to 12) and decreasing particle size (500-710 to 80-125). The maximum adsorption capacity was 500.0 (mg.g-1) at T = 25˚C, dp = 250-355 μm and pH = 12. The experimental data were analyzed by Langmuir, Freundlich, Temkin and Redlich-Peterson isotherms, and found that the Redlich-Peterson isotherm best fit the experimental data over the whole concentration range with R2 values lie between 0.9986 and 0.9999. Thermodynamic parameters such as standard Gibbs free energy (ΔG˚), standard enthalpy (ΔH˚), and standard entropy (ΔS˚) were calculated. The thermodynamic parameters of MB/clay system indicated spontaneous and endothermic nature of the adsorption process. The results demonstrate that Yemen bentonite is effective in the removal of MB from aqueous solutions and can be used as alternative of high cost commercial adsorbents.
Keywords:- Adsorption; Methylene Blue; Yemen bentonite.

EVALUATING OF FUNCTIONAL EFFICIENCY OF MODERN HOUSES SPACES IN MOSUL CITY

Omer Hazem Karofa

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 31-47

The research handles the measuring of functional efficiency in the modern Iraqi city taking Mosul city as a good example of this study, the problem of (lacking resources involved in the field of evaluating the functional efficiency of the modern houses spaces locally) was put on the table of discussion.
The theory depended by the research is represented by (the functional efficiency of any building is affected by the space arranging of the involved building) , tow main aims were achieved by the research, the first is represented by (evaluating the functional efficiency of the modern houses spaces locally) the second is concerned with (the possibility of reaching a sample of a space system concerned with the modern spaces houses in such a way that keep it functionally efficient as long as possible).
Doing so, it was possible to deal with one of the mathematical analysis methods using a computing program which is (syntax.exe), it provides us with a digital results so precise in analysis, in order to obtain the data, selected samples of modern houses were selected and analyzing them by space syntax theory indicators.
Once the theory was selected and the results were obtained, the research made several results by which many questions found their answers, these questions which were mentioned at the beginning of the research are:-
1. How can we collect the functional efficiency with the house space systematizing?
2. Is it possible to reach a sample of house in which the space systematizing can be effective in such way with the functional efficiency?
3. Is it possible to apply the dependant method in the analyzing on a different other space system of houses that are of different times or even of buildings that are of non-residential functions?
Answering these questions, the research realized that the house, as a functional system, containing all of the actions, is still lacking to the succeeding qualifications unless having these functions with certain indicators of the Space arranging that are contributing in some way in evaluating the functional efficiency of that house.

THE INFLUENCE OF APEX ANGLE ON MIXED CONVECTION IN A POROUS SECTOR CHANNEL

Manar Salih Mahdi

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 54-70

ABSTRACT: - The influence of apex angle on mixed convection in a horizontal porous sector channel is investigated. The analysis is performed by considering fully- developed hydrodynamically and thermally flow. The governing equations have been solved numerically using finite difference method. The channel is heated from the right surface, and cooled from the left one –both are held at constant temperature- while the top surface is adiabatic. The numerical analysis has been conducted in the following range of parameters: radius of the sector=4, (Pe=20(, (Ra*=100 and 1000(, the apex angle (Φ=30o, 60o, 75o and 90o). The results are presented to demonstrate the effect of increasing the apex angle on the streamlines, the isotherms and local Nusselt number. The highest stream function appears in a specified apex angle depending on Ra*. The local Nusselt number values are decreasing as the apex angle is increasing at (Ra*=1000), while at (Ra*=100) its values are increasing as the apex angle is increasing. A correlating equation is suggested to correlate ( (against apex angle (Φ) and (Ra*( for )Pe=20(.
Keywords: - porous, mixed convection, horizontal sector channel.

IMPROVEMENT OF GYPSEOUS SOIL BY PRE-WETTING

Safa Hussain Abid Awn

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 71-82

ABSTRACT:- Gypseous soil is one of problematic soils facing civil engineer. The problem appears when constructing heavy buildings or hydraulic structures on these soils after wetted by water from rainfall or from the raising of water table level from any source.
On the other hand gypseous soil is considerably strong and has good properties when it is dry. The dissolution of gypsum depends on many factors: gypsum content, temperature, atmospheric pressure and others. Number of Remedies for these soils was carried out by many investigators, some of these methods are not workable, and the others are expansive.
A new method of improving the collapsibility of such soil was presented by Prewetting Gypseous soil with water many cycles using laboratory and field models with different footing stress, which reduces the collapsibility of this soil primary. A laboratory model of 320 mm diameter and 472 mm height made from thick plastic was used. Two soils with different gypsum content 50% and 70%, brought from Aldor and Balad, in Salah Al Deen government in Iraq, was used. A footing of circular base (50 mm diameter), applies 45 kN/m2 and 100kN/m2 stresses with the aid of fix weights placed on it. The results of laboratory tests on the model samples shows a considerable reduction percent in the deformation ratio (Settlement/width of footing (S/B)) of 63% achieved from the 3rd wetting cycle by water for sample contain 50% gypsum. The reduction percent was 91% at the 3rd cycle of prewetting for sample containing 70% gypsum tested at stress level up to 45kN/m2, while it is 86% for the laboratory model with 100kN/m2 applied stress, with the same gypsum content. The results of field test for the soil containing70% gypsum tested at 100kN/m2 stress shows a pronounce improvement in the S/B value which gives a reduction percent reaches 90 %, which shows a considerable improvement in the collapsibility of this problematic soil.
Keywords:- Gypseous Soil, Soil Improvement.

SWITCHING ANGLE OPTIMIZATION BASED GENETIC ALGORITHMS FOR HARMONIC REDUCTION IN THREE-PHASE PWM STRATEGY

Osama Y. AL-Rawi

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 83-94

ABSTRACT :- In variable speed drive (VSD), it is desirable to reduce the harmonic effects, which causes current distortion and torque pulsation, besides, the harmonic power losses is an additional power losses that is introduced in the motor due to the presence of harmonic voltages.
However, the problem of the high total harmonic current distortion (THD) still exists specially at low and medium speeds by using sub-optimal pulse width modulation (PWM) strategy. In the past to generate optimized PWM, is done by defining a general PWM in terms of a set of switching angles. Which result in a set of nonlinear equations in terms of the unknown switching angles. These equations are nonlinear as well as transcendental in nature. There is no efficient method that can be applied to solve such equations. The practical method of solving these equations is a trial and error process. Taking all the factors into account, a numerical technique can be applied to solve these set of nonlinear equations, but with some limitations.
To overcome these limitations, Genetic algorithms (GAs) serves to search for optimal switching angles setting. In addition, the (THD) will be reduced, this lead to obtain the optimal PWM waveform and to simplify the practical implementation, and then improving the performance of the system output.
GAs were employed as a search and optimization engine. Normally the tuning of the switching angles is a trail and error problem.
In this paper, GAs provides a much simpler approach to off-line tuning of PWM switching angles than the rather complicated non-genetic optimization algorithms.
Keywords:- Optimization, Genetic algorithm, PWM.

PUNCHING SHEAR AND FLEXURAL STRENGTHS OF SELF COMPACTED CONCRETE NON-RECTANGULAR SHAPED FLAT PLATE SLABS

Ali H. Aziz

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 95-107

ABSTRACT :- This study is conducted to investigate experimentally the punching shear and flexural strengths of reinforced concrete flat plate slabs made with Non-Rectangular (triangular and trapezoidal) shaped. Four test self-compacting concrete slab groups were manufactured, each of which consisted of three slab specimens identical in size and shape but different in constituent’s properties. All slabs are simply supported along the all edges and subjected to single point load applied at the center of gravity of each slab.
Experimental results shows that the use of self compacting concrete improves the punching shear resistance and allows higher forces to be transferred through the slab-column connection. For slabs which were designed to fail in punching shear, the ultimate capacity of the tested specimens increased by (7%) to (20%) when the shape of slab specimens changed from triangular to trapezoidal. In contrast of slabs which were designed to fail in flexure, the ultimate capacity of the tested specimens increased from (16%) to (58%) when the shape of slab specimens changed from triangular to trapezoidal.
The cracking load depends essentially on concrete strength and not on slab configuration, but, the ultimate capacity depends on both, concrete strength and shape of slab.
Keywords:- Punching Shear, Flexural, Self compacted, Slabs, Concrete, Non-Rectangular

PROPOSED ALGORITHM FOR TCP/IP TRAFFIC OVER ATM NETWORK

Saad Qassim Fleh

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 108-124

ABSTRACT - In this work, a suggested algorithm is designed that operates at ATM Adaptation Layer (AAL) layer, this algorithm is named Adding Identification number and Matching (AIDM) algorithm. The resulting transport protocol from using AIDM algorithm is named as Improved TCP/IP Reno. AIDM is an efficient recovering technique that attempts to make TCPIP Reno performance less sensitive to cell losses. Improve TCP/IP Reno is presented and a result is compared with other TCPIP Reno .This result explain the network performance is enhanced about 20.53 % as average of the enhancement rates of the given samples and the period of time required to recover the damaged cell is reduce .
Keywords:- ATM network , TCP/IP Reno protocol , ATM Layers , Network traffic

NON-LINEAR ANALYSIS OF CONTINUOUS COMPOSITE CONCRETE–STEEL BEAMS UNDER CYCLIC LOADINGS

Ali Laftah Abbas

DIYALA JOURNAL OF ENGINEERING SCIENCES, Volume 4, Issue 1, Pages 125-143

ABSTRACT :- Non-linear analysis of continuous composite concrete–steel beams under cyclic loadings has been investigated in this paper. A three-dimensional finite element analysis (FE) ANSYS computer program(ANSYS version 9.0) was conducted to investigate the nonlinear behaviour of this beam up to failure through the prediction of the values of slip, deflection along the spans of the composite beam for different number of loading cycles up to one million cycles of the load of range (52%of the ultimate load of the beam). The results obtained from analyzing a continuous composite concrete-steel beam under cyclic loadings show good agreement with available experimental results and other available analytical results. A parametric study is also conducted in this paper to study the influence of some parameters such as the number of loading cycles, and the amount of load ratio on the values of slip and deflection. This parametric study shows that as the number of loading cycles increased, slip and deflection values along the composite beam will increased due to reduction in strength of all components of the composite beam, and the absolute values of maximum slip and maximum deflection will reduce as the load ratio changes from negative to positive signs .
Keywords:- Composite beams, continuous beams, concrete-steel beam, deflection, cyclic loads, shear connectors, slip