Ali Fahad Fahem; FATHI A. ALSHAMMA
Abstract
Leaf springs are commonly used in the suspension system of automobiles and are subjected to varying stress from dynamic loading leading to failure. An analytical method using formulation and solution technique classical laminated plate theory (CLPT) for design optimization of composite leaf springs under ...
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Leaf springs are commonly used in the suspension system of automobiles and are subjected to varying stress from dynamic loading leading to failure. An analytical method using formulation and solution technique classical laminated plate theory (CLPT) for design optimization of composite leaf springs under different dynamic loading is presented here. Different ratios of height/ width (h/b), and duration of time effect are conclusions. A numerical method using FEM (Ansys11.0) has been for solving the dynamic stress distribution in composite leaf springs. Both theoretical and numerical results give good agreement and the studies reveal that the model proposition flexibility has a significant influence on the system dynamic behavior and using likelihood with car industry automobile less than 500 kg. per wheel.
Kareem D.jaseem; Ali I. Al-Mosawi; Abbas A. Al-Jeebory
Volume 2, Issue 2 , June 2009, Pages 15-24
Abstract
In this research we studied the effect of flame retardant material addition which is zinc borate on the flame resistance for composite material consist of phenol formaldehyde resin reinforced by woven roving carbon fiber(0O-90O) with (225g/cm3) density . where we added zinc borate as a protected surface ...
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In this research we studied the effect of flame retardant material addition which is zinc borate on the flame resistance for composite material consist of phenol formaldehyde resin reinforced by woven roving carbon fiber(0O-90O) with (225g/cm3) density . where we added zinc borate as a protected surface layer from direct flame with (4mm) thickness on the surface of composite material and measuring the rang of its thermal resistance by applied thermal erosion test , which included exposition the flame retardant layer direct flame gas torch (butane-propane) with different exposed distances (10mm ,15mm ,20mm,25mm) and study the influence one substrate composite material as illustrated in the diagrams between surface temperature and time .
Ziad. M. Al-Makhyoul
Volume 2, Issue 2 , June 2009, Pages 25-43
Abstract
This study explains the effect of presence two adiabatic partitions fixed horizontally inside two dimensional enclosure filled with porous medium on natural convection heat transfer. The vertical walls of enclosure was insolated and the heat is transferred from the bottom to the above. A numerical study ...
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This study explains the effect of presence two adiabatic partitions fixed horizontally inside two dimensional enclosure filled with porous medium on natural convection heat transfer. The vertical walls of enclosure was insolated and the heat is transferred from the bottom to the above. A numerical study is used to solve the governing equations which represented by momentum, energy and continuity equations with finite difference method and it was in non-Darcian heat flow. The study included change in modified Rayleigh number (100 to 500), an inertia parameter (10-2 to 10-4), change the upper partition length at (30%-50%-70%) with stay the lower partition is constant at (30%) and opposite, change the lengths of two partitions at (30%-50%-70%) together, change the positions of two partitions at (20%-30%-40%) for the lower partition and (60%-70%-80%) for the upper partition and in addition to divergence between the two partition. The study at a constant aspect ration at (A=1.0). The results are showed the reduction in heat transfer compare with the no partitions. When the increase in the length of upper partition, the reduction in heat transfer of (68.2%) while when the increase in the length of lower partition the reduction reach to (66.4%) and the increase in the lengths of two partitions lead to the reduction to (73.2%). The reduction is (50%) when the two partitions near from both and when the upper partition near the cold wall and the lower partition near the hot wall, finally the heat transfer is reduced with (46.3%) when the change in the position of partitions toward the cold wall.
Aseel Hadi Hamza; Amar Jabar Badr; Saad Hameed Najem
Volume 2, Issue 2 , June 2009, Pages 44-54
Abstract
This research deals with studying the effect of graphite on the wear resistance of aluminum – silicon alloy. Firstly this alloy (master alloy) is prepared using casting method then graphite particles added in weight ratio (5.5 %) by using vortex technique after that the master alloy and composite ...
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This research deals with studying the effect of graphite on the wear resistance of aluminum – silicon alloy. Firstly this alloy (master alloy) is prepared using casting method then graphite particles added in weight ratio (5.5 %) by using vortex technique after that the master alloy and composite material casted in dies and prepared for sliding wear test , wear test was made under different conditions of applied load , sliding distance and surface roughness at the room temperature. The results show that wear rate increases with increasing any of the above conditions, also the composite material show higher resistance wear than of master alloy.
Waleed Mohammad Abid
Volume 2, Issue 2 , June 2009, Pages 55-62
Abstract
In many electric circuit boards thermally induced buoyancy effects are not always sufficient to adequately cool high density electronic packages found in modern circuit boards. Instances thermal enhancement techniques, such as heat sinks, must be used to increase the effective surface area for heat transfer ...
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In many electric circuit boards thermally induced buoyancy effects are not always sufficient to adequately cool high density electronic packages found in modern circuit boards. Instances thermal enhancement techniques, such as heat sinks, must be used to increase the effective surface area for heat transfer so lower the thermal resistance between sources and sink.Both vertical rectangular and pin finned surfaces were studied to show the shape effect and natural convection heat transfer coefficient. The thermal dissipated from vertical rectangular finned surfaces greater than pins finned surfaces. The overall thermal resistance of the pins finned surfaces greater (31%) compared with vertical rectangular finned surfaces.An empirical equation was predicted to calculate average natural convection heat transfer coefficient from vertical rectangular and pin fins. The results show an excellent convince with the Literature review where the overall error was about (0.12%).
Ahmed S. Abdul-Aziz; Ahmed N. Rashid
Volume 2, Issue 2 , June 2009, Pages 63-72
Abstract
The effect of annealing at different temperatures on the formability of aluminum sheet of thickness (1.5) mm was studied in this work. Experimental testing including tension test, stretching test by using hemispherical punch without lubricant on the un treated and the annealed specimens. It was noticed ...
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The effect of annealing at different temperatures on the formability of aluminum sheet of thickness (1.5) mm was studied in this work. Experimental testing including tension test, stretching test by using hemispherical punch without lubricant on the un treated and the annealed specimens. It was noticed that the best annealing temperature is about (275° C), and the best time is about (10) minutes. Improvement of formability occurred due to annealing process on the aluminum sheet.
Sada A. alyasri
Volume 2, Issue 2 , June 2009, Pages 73-82
Abstract
A new approach to calculate the delay time on roads due to the deterioration of the Level Of Service (LOS) was adopted. The approach bases on the daily traffic volume and road volume capacity. The time value was accordingly estimated based on direct and indirect costs and then compared to the cost of ...
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A new approach to calculate the delay time on roads due to the deterioration of the Level Of Service (LOS) was adopted. The approach bases on the daily traffic volume and road volume capacity. The time value was accordingly estimated based on direct and indirect costs and then compared to the cost of the LOS improvement. The results of comparison were demonstrated through figures and tables The purpose of this research was to provide decision maker with necessary and optimum way decide on whether maintanence or road exteusion is proper solution when los is deterioratedThe comparison has shown that time value curves intersect cost of construction a maintanence at LOS then we shall know the boundary to improve. LOS by construction new line, upgrading low LOS roads depends on both the daily traffic volume and the present LOS of the road.
Ahmed M. Alsuliman; Haider S. Abdullah
Volume 2, Issue 2 , June 2009, Pages 83-93
Abstract
In this study, a practical models are accomplished on a group of houses in Diwaniyah ,Halla ,Karabla,and Najaf. A PVC pipe of (6 inch) diameter and (0.5m) length associated with an electrical pump to raise the level of water to the circulating tank open up which is basin at the earth's surface. A vertical ...
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In this study, a practical models are accomplished on a group of houses in Diwaniyah ,Halla ,Karabla,and Najaf. A PVC pipe of (6 inch) diameter and (0.5m) length associated with an electrical pump to raise the level of water to the circulating tank open up which is basin at the earth's surface. A vertical (PVC) pipe was placed at the bottom of basin of the circulating tank and its length between (12-15) m which is used to lower the water to the underground water with holes of (3mm) diameter every each (5cm) long after the depth of (2m) from the connecting region. A simple treatment was done on the sewage water by the septietank and circulating tanks to make the pollution near to the accepted ratios during the oxidation of organic matter in the sewage water. During this study 90% of the sewage water was ejected to the groundwater with a continuous monitoring to its level. The results showed that the study model was appropriate to (250) person for each unit. It is the way to take advantage of sewage water in ecological development through the shipment of groundwater
ALI H. GHAWI
Volume 2, Issue 2 , June 2009, Pages 94-107
Abstract
The reaction that takes place in a process tank is in a large way dependent on the internal hydraulics of the tank, irrespective of the type of tank. In some tanks mixing is desirable in others plug flow is desirable. In most tanks it is very hard to achieve either of the two. This is partially due to ...
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The reaction that takes place in a process tank is in a large way dependent on the internal hydraulics of the tank, irrespective of the type of tank. In some tanks mixing is desirable in others plug flow is desirable. In most tanks it is very hard to achieve either of the two. This is partially due to the fact that the area through which the fluid enters the tank is small in relation to the tank cross sectional, complex geometries and changes of fluid direction. Baffles can in some cases offer cost effective and simple solutions. This paper demonstrates how Computation Fluid Dynamic (CFD) can be used to improve process tanks performance in Iraq water treatment plant by the introduction of baffles.
Dr.Haider K. Ammash; Muthana H. Muhaisin
Volume 2, Issue 2 , June 2009, Pages 108-128
Abstract
The study aims to present anew form of the effective moment of inertia by enhancement Branson's model to take the effect of several factors such load type(concentrated, uniformly distribution, and two points) loads, shear deformations affect are also considered. These deformations depend on the span ...
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The study aims to present anew form of the effective moment of inertia by enhancement Branson's model to take the effect of several factors such load type(concentrated, uniformly distribution, and two points) loads, shear deformations affect are also considered. These deformations depend on the span to depth ratio. The results of the presented model were compared with (experimental results, Branson's model results, and results of other models). The results of the present model give best agreement with experimental results than Branson's and the other models; the results showed that the effective moment of inertia reduced by about 27% for span to depth ratio of (20 to 5) due to shear deformation effects.
Salam Khudhair Abdullah; Nabeel H. Ameen; Hydar K. Esa
Volume 2, Issue 2 , June 2009, Pages 129-135
Abstract
The technology of ion exchange is applied in batch operation for removing potassium-40 as from liquid solutions (prepared in laboratory by solved known amount of KCl in known amount of distilled water. A measured quantity of the ion exchange medium (bentonite clays) is mixed with radioactive solution ...
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The technology of ion exchange is applied in batch operation for removing potassium-40 as from liquid solutions (prepared in laboratory by solved known amount of KCl in known amount of distilled water. A measured quantity of the ion exchange medium (bentonite clays) is mixed with radioactive solution containing potassium-40 in a suitable mixing vessel. The activity concentrations of liquid solution containing potassium-40 in the influent and effluent samples are measured by gamma ray spectroscopy system composed of a high purity germanium detector with 40% efficiency coupled to an 8192 channel personal computer analyzer. The amount of exchanger media required and the rate of exchange is determined by laboratory tests. The distribution coefficient for bentonite clays for removing K-40 in batch operation (0.104815 l/gm) is estimated by correlation line method, with a correlation coefficient between the observed and the predicted data of 96%. To ensure accuracy and reliability of the collected data, the test is used to measure deviations between the observed and expected K-40 activity concentration captured by the bentonite clays and passed through it. No significant difference is observed between observed and expected data at 5% significant level. The results indicate that the distribution coefficient can be used in predicting the amount of an ion exchanger media needed to remove potassium-40 with a certain decontamination factor.
Ryidh A. Yasir; Zaidun Naji Abudi
Volume 2, Issue 2 , June 2009, Pages 136-148
Abstract
The improving of living condition and increasing of population density growth assist in increase the quantity and quality of domestic solid waste in households in Nassiriya city.
A samples of solid waste have been collected from households in Nassiriya city to know the quantity of solid waste generated. ...
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The improving of living condition and increasing of population density growth assist in increase the quantity and quality of domestic solid waste in households in Nassiriya city.
A samples of solid waste have been collected from households in Nassiriya city to know the quantity of solid waste generated. Households classified into three zones according to economic status (high, middle and low income levels). Samples collected for seven months, from January to July 2008.
This paper explains that the generation rate of solid waste for person or capita changes from each income level to another and from month to other and we can represent 0.68 kg/cap./day as average of domestic solid waste generated in present time in city, the quantity of solid waste generated in Nassiriya city is equal to 22.15 ton/day this only for domestic waste (solid waste from commercial, industrial and medical waste not reported in this paper).
Value of density was calculated is equal to 275.33 kg/m3, the percent of each individual component for solid waste components also calculated and for seven months for each income level. These percent shows that the most common components is organic (food) waste which is participle and its percent in range of (61.88 % to 69.95 %) and these value is similar with other results in other cities of Iraq.
The compressive of results of this paper with other results shows its similar to Iraqi cities and differs to Europe united cities.
Abdulhaq Hadi
Volume 2, Issue 2 , June 2009, Pages 149-163
Abstract
The flexible pavement layers attach at every hours during the day to hundred thousand from several traffic loading according to number of axles, number of wheel for each axles (Dual and Triple …,etc) and tire pressure.
These different types of above variable generate stresses, strains and defilations ...
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The flexible pavement layers attach at every hours during the day to hundred thousand from several traffic loading according to number of axles, number of wheel for each axles (Dual and Triple …,etc) and tire pressure.
These different types of above variable generate stresses, strains and defilations in the pavement layers (with overlap stresses and deflection) caused to fatigue of pavement to reduced pavement life. In order to design exchange these loads to Equivalent Single Wheel Load (ESWL).
Little programs are available to solve this problem as an exact solution. In this work using 3D finite element model make by SAP 2000 program based on the equal maximum vertical interface deflection for equal contact area concept. The results are compared with the analytical solution obtained from Kenlayer Computer program.
Amer D. Zmat; Ali H. GHAWI
Volume 2, Issue 2 , June 2009, Pages 164-176
Abstract
Biofilm models were used to model and predict the performance of Rotating Biological Contactors (RBC) in wastewater treatment plants. Assessment techniques have been adopted to evaluate this method in terms of hydraulic loading and Biochemical Oxygen Demand (BOD) removal. The results revealed that RBC ...
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Biofilm models were used to model and predict the performance of Rotating Biological Contactors (RBC) in wastewater treatment plants. Assessment techniques have been adopted to evaluate this method in terms of hydraulic loading and Biochemical Oxygen Demand (BOD) removal. The results revealed that RBC not only is efficient, but also proven to be odor controlling reactor. RBC provides efficient mixing and reduces time of retention to minimum, so that a great reduction of area of treatment plants will be achieved.
Thulfikar R. Al- Husseini Munaf A. Al- Rammahi; Haider K. Ammash
Volume 2, Issue 2 , June 2009, Pages 177-191
Abstract
In the present study, the optimum hydraulic and structural design of inverted siphon has been studied. Modified Hooke and Jeeves method considered in the present study and some modifications were doing. These modifications are:1) modification on the assumed initial base points, 2) modification on the ...
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In the present study, the optimum hydraulic and structural design of inverted siphon has been studied. Modified Hooke and Jeeves method considered in the present study and some modifications were doing. These modifications are:1) modification on the assumed initial base points, 2) modification on the value of step length, 3) modification on the value of the reduced step length at each trial. Many shapes of inverted siphon considered as (circular section, square section, and rectangular section). A computer program was writing by FORTRAN90 language depending on the method mentioned. STAAD Pro2006 software program was considering to structural analysis and design of inverted siphon. Many examples solved to check the accuracy of the written program.
Haider Hussein Alwan
Volume 2, Issue 2 , June 2009, Pages 192-205
Abstract
The well waters are important source to provide potable water by using storage water under ground level, it important source to provide potable water in desired.
In this study, 14 wells has been driven in some of villages Dyala governmental. A study has been selected samples from well waters, it tested ...
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The well waters are important source to provide potable water by using storage water under ground level, it important source to provide potable water in desired.
In this study, 14 wells has been driven in some of villages Dyala governmental. A study has been selected samples from well waters, it tested chemically & physically especially (Total Dissolved Solids TDS) in Central Organization for Standardization & Quality Control in Baghdad.
A study has been drawing necessary graphs between salinity concentrations ratios in well waters & the standard limits in Iraqi standards for potable water No. 417, Also the study has been taken suitable photos for drilling, putting filter pipe screen & gravel filter pack & isolated matter between ground water and shallow water.
By this study, we can depend on the wells to provide potable water. From test results, just two wells are passing all important lab. Tests, it clean water no pollution & depend on it directly to provide potable water after disinfection stage, while the rest required to desalinate by (Reverse Osmosis system) & disinfection processes, a few of wells doesn't desalinate because high cost.
Muhammed S. Muhammed; Ali H. Nahhab; Haider K. Ammash
Volume 2, Issue 2 , June 2009, Pages 206-214
Abstract
The present investigation was carried out to study the possibility of using waste glass of size up to 5mm as a fine aggregate in concrete and mortar. The waste glass was used as a partial weight replacement of sand with percentages of 10, 20, 30 and 40 %. The results have indicated that increasing the ...
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The present investigation was carried out to study the possibility of using waste glass of size up to 5mm as a fine aggregate in concrete and mortar. The waste glass was used as a partial weight replacement of sand with percentages of 10, 20, 30 and 40 %. The results have indicated that increasing the fractions of sand replacement by waste glass leads to reduce the compressive and tensile strength for both mortar and concrete. Up to 20 % replacement, the 28 days compressive strength of concrete and mortar is about 92 and 95 percent from the reference strengths, respectively. Also, it was found that the expansion of mortar specimens increase with increasing the waste glass content in the mix. At 20 % of sand replacement by waste glass, the expansion is slightly higher than that for the control specimens.
Thaar Saud Al-Gasham
Volume 2, Issue 2 , June 2009, Pages 215-228
Abstract
Structural standards and codes of practice are reviewed continuously and improvements are implemented as research findings reveal more accurate method of design. Design for shear unlike design for bending and axial forces, which have been perfected over the years, because of its behavior is difficult ...
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Structural standards and codes of practice are reviewed continuously and improvements are implemented as research findings reveal more accurate method of design. Design for shear unlike design for bending and axial forces, which have been perfected over the years, because of its behavior is difficult to predicate accurately. In spite of many decades of experimental research and the use of highly sophisticated analytical tools, it is not yet fully understood.
This paper reviews the provisions of the current standards in relation to shear of reinforced concrete beams, highlights their weaknesses and strengths and compares their predictions with 122 test beams failing in shear (from existing tests). It was found that five codes [ACI, BS, NZ, EUR, NOR] lead to some, unsafe strength predictions. In other cases these methods could lead to excessively conservative predictions. To examine the accuracy of the existing methods, statistical analysis [Mean ( ), Standard Deviation (SD), and Coefficient of Variation (COV)] of shear failure strength to predicted design value are used.
Khamail Abdul-MahdiI Mosheer; Nameer A. Alwash; Ammar Y. Ali
Volume 2, Issue 2 , June 2009, Pages 229-244
Abstract
This research deals with nonlinear analysis of reinforced concrete deep beams with openings by three dimensional finite element method under static load. The constitutive models of the material nonlinearity are adopted to take into account the nonlinear stress-strain relationships of concrete and steel, ...
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This research deals with nonlinear analysis of reinforced concrete deep beams with openings by three dimensional finite element method under static load. The constitutive models of the material nonlinearity are adopted to take into account the nonlinear stress-strain relationships of concrete and steel, such as (cracking and crushing of concrete, and yielding of reinforcement). A twenty-noded isoparametric brick element with sixty degrees of freedom is employed to model the concrete while the reinforcing bars are modeled as axial members embedded through the brick element with perfect bond. Parametric study is considered to deal with the effect of opening location on the ultimate strength of deep beams. It was found that providing an opening at the shear zone causes sharp decrease in ultimate load by about (31%-56%) for simply supported deep beams. Therefore, if the designer has to provide an opening in a deep beam, he should keep it far away from the load path
Sallal Rashid Al-Owaisy
Volume 2, Issue 2 , June 2009, Pages 245-252
Abstract
An experimental program was adopted in this study to investigate the degree of dependency on the using of ultrasonic pulse velocity (UPV) to evaluate the residual strength of concrete exposed to high temperatures as in the case of fires. This experimental program focus on the relationship between compressive ...
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An experimental program was adopted in this study to investigate the degree of dependency on the using of ultrasonic pulse velocity (UPV) to evaluate the residual strength of concrete exposed to high temperatures as in the case of fires. This experimental program focus on the relationship between compressive strength and UPV of high strength concrete (HSC) after high temperature exposure. The tests were carried out using 100mm cubes. Three concrete mixes were used with target compressive strengths of 40 MPa, 60 MPa and 80 MPa. Totally fifty four concrete cubes were tested in this study. The specimens were divided into three groups according to their original compressive strength. Four temperature levels of 150oC, 350oC, 500oC and 700oC were adopted. Three specimens from each group were heated to each temperature level, cooled and then tested. While, six specimens from each group were tested as reference specimens without heating. The test results show that both concrete compressive strength and UPV decreased after high temperature exposure. Another observation is that at temperatures (150oC and 350oC ), the normal strength concrete (NSC) suffered higher percentage loss in strength than HSC, while the opposite stands at 700oC. Also it is observed that the UPV showed higher percentage loss than in compressive strength for both NSC and HSC at temperatures of 350oC and higher. Finally, it was found that the UPV-temperature behavior differs than the compressive strength-temperature behavior
Mohammed Khachi Al-Zairjawi
Volume 2, Issue 2 , June 2009, Pages 253-261
Abstract
This paper describes a study on the effect of adding cement and silica fume with cement on the engineering properties (Compaction and Shear strength) of the clayey soil. Inorganic clay with low plasticity was used in this study as a natural soil. A series of laboratory experiments have been implemented ...
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This paper describes a study on the effect of adding cement and silica fume with cement on the engineering properties (Compaction and Shear strength) of the clayey soil. Inorganic clay with low plasticity was used in this study as a natural soil. A series of laboratory experiments have been implemented and varieties of samples were made by mixing both cement and silica fume with cement . Four different percentages of cement (2%, 4%, 6% and 8%) and three different percentages of silica fume (2%, 4% and 6%)were used as a stabilization materials . Test results show that adding cement and silica fume with cement decreases the maximum dry density and increases the optimum moisture content. The unconfined compressive strength of the soil was found to increase significantly with increase in the cement and silica fume with cement content especially after a long curing period.
Waqid Hameed Al-Mussawi
Volume 2, Issue 2 , June 2009, Pages 262-274
Abstract
The junction open channel flow is encountered in many hydraulic engineering such as irrigation ditches, wastewater treatment facilities and fish passage conveyance structures. The flow behavior at junction becomes very complex because of the interaction between the branch and main channel, that’s cause ...
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The junction open channel flow is encountered in many hydraulic engineering such as irrigation ditches, wastewater treatment facilities and fish passage conveyance structures. The flow behavior at junction becomes very complex because of the interaction between the branch and main channel, that’s cause many complex problems such as local sedimentary, channel scour and sidewall erosion and others. This paper provides detail application of numerical solution (Finite Volume) by FLUENT-2D software in simulation of 90º open channel junction flows. Numerical simulations undertaken in present two dimensional work use Standard k-ε turbulence model. Comparisons have been made between numerical results and measured experimental velocities of Weber et al. (2001), good agreement between the model predictions and experimental measurements have been obtained. The model is then applied to investigate the dimensions of separation zone. The simulation results show that separation zone size increases as the discharge ratio of the upstream main channel to the downstream channel decreases.
Kareem Dakeel Jasem; Ahmed Hashm Yousif; Abas Naji
Volume 2, Issue 2 , June 2009, Pages 275-287
Abstract
The structure of flow and heat transfer characteristics over a heated fin (at constant heat flux) in rectangular duct with using triangle protrusion has been studied numerically. An incompressible flow and finite volumes method (FVM) in general coordinates with collocated grid arrangement are ...
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The structure of flow and heat transfer characteristics over a heated fin (at constant heat flux) in rectangular duct with using triangle protrusion has been studied numerically. An incompressible flow and finite volumes method (FVM) in general coordinates with collocated grid arrangement are used to solve two dimensions continuity, Navier – Stokes and energy equations. The Prandtl number and Reynolds number are takes as 0.71 and 2000 respectively.
At present study, different lengths of base of triangle protrusion (d/H = 0, 0.26, 0.53, 0.8, 1.07, 1.33) at (l/H= 0.13) was used. The results were compared with the case of flow inside duct without using protrusion. The results indicate that heat transfer and pressure drop is affected by the length of protrusion base especially near the triangle protrusion. The results illustrate that the heat transfer will be increasing with decreases the length of protrusion base. This study identifies an enhancement in the average heat transfer with increasing in pressure drop
Ali Fahad Fahem; Fathi A. Alshamma
Abstract
In this work, a study of the effect of impact loading on dynamic crack propagation in thin and isotropic thick plates for two types of material, stainless steel, and aluminum, are investigated analytically and numerically to give a complete study of 3D crack growth of simply supported plate with internal ...
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In this work, a study of the effect of impact loading on dynamic crack propagation in thin and isotropic thick plates for two types of material, stainless steel, and aluminum, are investigated analytically and numerically to give a complete study of 3D crack growth of simply supported plate with internal crack at the center of plate. The dynamic stress intensity factor (DSIFs), the velocity of dynamic crack propagation, and the deep of the crack normal to the crack face for different angles from the crack tip have been calculated when the Contact of a cylindrical impactor on isotopic plates is considered, to support the analytical result for DSIFs with a numerical package result (Ansys-10). This is based on the finite element method used to investigate the stress and the values of dynamic stress intensity factors at the crack tip by full transient dynamic Analysis using 3D (element, Solid-90). The results from the Airy stress function method give good agreement with the results of Ansys for a long time duration in impact loading while the energy method is in agreement with the Ansys package for some time and then becomes limited. In addition, the DSIFs and crack propagation velocity are increasing with an angle from the crack tip and velocity impact increasing.
Essam Z. Fadhel; Mustafa T. Hussein
Volume 2, Issue 2 , June 2009, Pages 304-314
Abstract
This paper presents the symbolic analysis of the dynamic model of flexible robot arm. A planar single flexible link is considered. The finite element method is used for dynamic modeling of the system; the link is modeled as single finite element to simplify the problem. A symbolic algorithm is developed ...
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This paper presents the symbolic analysis of the dynamic model of flexible robot arm. A planar single flexible link is considered. The finite element method is used for dynamic modeling of the system; the link is modeled as single finite element to simplify the problem. A symbolic algorithm is developed using MatLab program, general symbolic solution describing the dynamic behavior of single link flexible manipulator is obtained; including two types of boundary conditions, payload and frictional terms. The effect of physical parameters of the manipulator on the characteristics of the system and the impact of their variation on the transfer function features of the system are clearly shown by the symbolic algorithm presented in this paper
Inad F. Mustafa
Volume 2, Issue 2 , June 2009, Pages 315-323
Abstract
The increased role of advanced materials in mechanical design optimization has purred the development of new material types and combinations previously unavailable to the designer .These new materials give the designer the ability to design higher density systems by matching the material characteristics ...
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The increased role of advanced materials in mechanical design optimization has purred the development of new material types and combinations previously unavailable to the designer .These new materials give the designer the ability to design higher density systems by matching the material characteristics of all parts within the system .Certain metal matrix composites now allow the designer to select needed material properties over a fairly large range (thermal expansion , conductivity and material strength for example ).The current work has been made for the evaluation of coefficient of thermal expansions (CTE) of Aluminum based cast composites reinforced with mixture of (Al2O3 ) and (SiC) particles with different volume fraction . The cast composites have been prepared by liquid metallurgical route .The results show that (CTE) significantly increased with increasing temperature up to 400C◦ .But it has been observed that (CTE) decreases with increasing volume fraction of reinforcing particles .The ( CTE ) values were found to be comparable with theoretical results .Turner model showed conformance with the current experimental results.
Khaldoon F. Brethee
Volume 2, Issue 2 , June 2009, Pages 324-334
Abstract
The natural frequencies of composite laminates plate with effect of various plate parameters have been studied using ANSYS5.4 program. Laminate composites are increasing used in various mechanical structures and industrial applications, due to their higher stiffness and higher strength-to-weight ratio. ...
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The natural frequencies of composite laminates plate with effect of various plate parameters have been studied using ANSYS5.4 program. Laminate composites are increasing used in various mechanical structures and industrial applications, due to their higher stiffness and higher strength-to-weight ratio. The effects of number of layers, angle of fiber orientation, boundary conditions, width to thickness ratio and laminate arrangement with the natural frequencies of plate having cutout at the center are studied. The non-dimensional fundamental frequency of vibration is found to increase with increase in width to thickness ratio and angle of fiber orientation. The natural frequencies of plate depend on size and shape of the cutout, with increasing values from the plate without cutout because the mass of the plate decrease. The effect of number of layers is found to be insignificant beyond four layers and the laminate arrangement show different results between symmetric and anti-symmetric laminate plate. Some of the results compared with M.K.Pandit et al. [2], that have various size of rectangular cutout at the center, with good agreement results
Muayad Muhammad Sadiq; Zaid M. Hassan; Ghassan Fadhil Muhammad
Volume 2, Issue 2 , June 2009, Pages 335-352
Abstract
The centrifugal fan is the most widely used because it can efficiently move large quantity of the gas over a wide range of pressures. The flow that enters throughout the impeller is analyzed by using a streamline curvature technique, this method used for a compressor, by neglect the term of gas density ...
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The centrifugal fan is the most widely used because it can efficiently move large quantity of the gas over a wide range of pressures. The flow that enters throughout the impeller is analyzed by using a streamline curvature technique, this method used for a compressor, by neglect the term of gas density change. The turbulent flow is modeled by using algebraic eddy viscous model which based on the mixing length, the turbulent model is applied on the hub to shroud stream surface. The shock in the present work is form by increasing the volume flow rate in put to the impeller .The impeller that chosen in this work is the impeller of the pre-heater fan in the heating system of clinker in AL-Muthanna factory of cement, which has back curved blade. The results prove that the increasing in the volume flow rate (forming shock losses) has an effect on the velocity profile and static pressure, so that where the volume flow rate increase the velocity profile increase and static pressure decrease.
Ahmed Ali Shaker; Mohamed Fadhil Thabit
Volume 2, Issue 2 , June 2009, Pages 353-367
Abstract
In this work a boundary layer analysis for free convection flow of viscous, incompressible fluid past over vertical plate is presented. A computer program is developed in Quick basic language to obtain numerical solutions for the resulting governing equations (mass, energy, and momentum). A parametric ...
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In this work a boundary layer analysis for free convection flow of viscous, incompressible fluid past over vertical plate is presented. A computer program is developed in Quick basic language to obtain numerical solutions for the resulting governing equations (mass, energy, and momentum). A parametric study of all involved parameters is conducted and a representative set of numerical results for the velocity profile and temperature distribution are illustrated graphically and physical aspects of the problem are discussed. The validity of results is verified and shows that there is a good agreement between the results of the present numerical solution and the correlation related to it.
Maase Fasel Mailak
Volume 2, Issue 2 , June 2009, Pages 368-378
Abstract
The aim of this study was to investigate elasto-plastic thermal stresses in a thermoplastic of Thick Spherical vessels under high pressure The present study deals with spherical shells analysis, The elastic and plastic theory of spherical shell is consider in this search, with a thick sphere subjected ...
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The aim of this study was to investigate elasto-plastic thermal stresses in a thermoplastic of Thick Spherical vessels under high pressure The present study deals with spherical shells analysis, The elastic and plastic theory of spherical shell is consider in this search, with a thick sphere subjected to different types of loading such as internal pressure, external pressure and thermal loading have been studies. The Tresca yield condition used in this study. When the applied pressure exceeds the minimum pressure required to initiate the yielding at the inner radius, plastic zone starts to be formed. The residual stress components also were calculated using elastic and elasto-plastic solution result
Adnan Sh. Jabur; Heider. Y. Thamir
Volume 2, Issue 2 , June 2009, Pages 379-393
Abstract
The object is to get simulated observation of the solidification front movement inside casting, which was extracted from theoretical simulation of the solidification process, in the prediction of shrinkage cavities locations in the final ingots. A (Fortran) program was developed using the finite difference ...
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The object is to get simulated observation of the solidification front movement inside casting, which was extracted from theoretical simulation of the solidification process, in the prediction of shrinkage cavities locations in the final ingots. A (Fortran) program was developed using the finite difference method. Several factors were taken into consideration in this system, such as the variation of liquid and solid volume fractions during solidification, changing the thermophysical properties of the cast metal with changing metal state and temperature. Also, the latent heat was introduced as an isolated source term to the mentioned equation. The verification of the system efficiency was achieved by the comparison between the cavity location in theoretical and real casting. There was a good agreement. Finally, the simulated cooling curves of selected points inside the casting were studied.
Salam Hadi Hussain
Volume 2, Issue 2 , June 2009, Pages 394-412
Abstract
Single-phase air flow periodically developed at constant property (Pr=0.7), laminar forced convection in two-dimensional sinusoidal corrugated-plate channels, which are maintained at uniform wall temperature are considered. The governing differential equations for continuity, momentum, and energy equations ...
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Single-phase air flow periodically developed at constant property (Pr=0.7), laminar forced convection in two-dimensional sinusoidal corrugated-plate channels, which are maintained at uniform wall temperature are considered. The governing differential equations for continuity, momentum, and energy equations are solved computationally using finite-volume technique, where the pressure term is handled by the SIMPLE algorithm. The computational grid is non-orthogonal and non-uniform, and it is generated algebraically. All the dependent variables are stored in a non-staggered manner. For the two-dimensional problem, numerical solutions are obtained for a wide range of channel corrugation aspect ratios (0.25 ≤ γ ≤ 1.0), plate spacing ratio (0.25 ≤ ε ≤ 1.5), and flow rates (10 ≤ Re ≤ 1000). The flow field is found to be strongly influenced by γ, ε and Re, and it displays two distinct regimes: a low Re or γ, ε undisturbed laminar-flow regime, and a high Re or γ, ε swirl-flow regime. In the no-swirl regime, the flow behavior is very similar to that in fully developed straight-duct flows with no cross-stream disturbance. In the swirl regime, flow separation and reattachment in the corrugation troughs generates transverse vortex cells that grow spatially with Re, γ and ε, and the transition to this regime also depends on Re, ε and γ. The mixing produced by these self-sustained transverse vortices is found to significantly enhance the heat transfer, depending upon Re, γ and ε, with a relatively small friction factor penalty.
Salih Abdul Jabbar Salih
Volume 2, Issue 2 , June 2009, Pages 413-424
Abstract
This paper deals with the prediction of the overall gas holdup g in slurry bubble column depending on wide range of databank of around 69 measurements collected from the open literature. Correlation for gas holdup was derived using combination of dimensionless analysis and Genetic Algorithm. The correlation ...
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This paper deals with the prediction of the overall gas holdup g in slurry bubble column depending on wide range of databank of around 69 measurements collected from the open literature. Correlation for gas holdup was derived using combination of dimensionless analysis and Genetic Algorithm. The correlation takes in consideration the physical properties of liquid and gas that effect on gas holdup and therefore effect on the design of slurry bubble column. Also a comparison between the correlation driven from Genetic Algorithm and a new correlation driven using Quasi-Newton method was made and found that the Average Absolute Relative Error (AARE) was 10.8 % and 16.1%, respectively. This shows that the use of Genetic Algorithm is improve the prediction of gas holdup in slurry bubble column.
Balasim A. Abid; Dr. Rahman Sh. Abdulmohsin; Mr. Hisham M. Al.Tamimi
Volume 2, Issue 2 , June 2009, Pages 425-438
Abstract
Time-averaged local heat transfer coefficient profiles were studied in a 0.2 m bubble column diameter using air-water system. The effects of the superficial gas velocity and axial locations (Z/D) on the heat transfer coefficient and its radial (r/R) profiles were investigated in bubble column. Significant ...
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Time-averaged local heat transfer coefficient profiles were studied in a 0.2 m bubble column diameter using air-water system. The effects of the superficial gas velocity and axial locations (Z/D) on the heat transfer coefficient and its radial (r/R) profiles were investigated in bubble column. Significant differences were observed between heat transfer coefficients in the axial directions viz. in the bulk flow region (Z/D=4.8) higher than in the distributor region (Z/D=0.28) by 15% -23% for increasing the superficial gas velocity from 0.03-0.35 m/s. The heat transfer coefficient increase with superficial gas velocities and the values in the center of the column were 8–12% greater than those near the wall region .The characteristics of bulk flow region have large variation in radial direction and little in axial direction for the values of heat transfer coefficients.
Rafid Kadhem Abbas
Volume 2, Issue 2 , June 2009, Pages 439-458
Abstract
The present paper deals with using a useful method to monitor the wear of the teeth of milled tooth bits during drilling. This approach is done by using two dimensionless parameters TD (dimensionless torque) and RD (dimensionless rate of penetration) . By plotting TD vs. RD , The constants a1 and a2 ...
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The present paper deals with using a useful method to monitor the wear of the teeth of milled tooth bits during drilling. This approach is done by using two dimensionless parameters TD (dimensionless torque) and RD (dimensionless rate of penetration) . By plotting TD vs. RD , The constants a1 and a2 could be determined and both used to calculate the two other dimensionless parameters ED (bit efficiency) and FD (bit dullness) as a bit dullness evaluation indicators , which could be used rather than other traditional techniques. This approach applied on three wells , Zubair #166 , Zubair #162 and Zubair #174 in Zubair field Southern Iraq .The obtained results could be useful to detect bit wear and according to that, the decision of pulling and using new bits could be determined easily and therefore drilling operations will be actively done with lowest costs and efforts. .
Ali A. Jazie Al-Khaledy
Volume 2, Issue 2 , June 2009, Pages 459-476
Abstract
In chemical technology and power engineering, equipment containing heat exchanging pipes and various cylindrical links immersed into moving fluid was often used. The estimation of the hydrodynamic action on these elements is based on the solution of the plane problem on the flow past a cylinder. In the ...
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In chemical technology and power engineering, equipment containing heat exchanging pipes and various cylindrical links immersed into moving fluid was often used. The estimation of the hydrodynamic action on these elements is based on the solution of the plane problem on the flow past a cylinder. In the hydrodynamics of inviscid flow past a body of nonzero thickness, it was assumed that there are regions near the body in which the flow accelerates from the front stagnation point to the midsection and decelerates behind the midsection. According to the Bernoulli theorem, a pressure counter-gradient arises in the deceleration region, which acts both in the outer flow and in the boundary layer. For the inviscid flow, the fluid particles store sufficiently much kinetic energy in the acceleration region to overcome this barrier, but in the frictional flow, the fluid particles that remain in the boundary layer cannot reach the region of higher pressure. They are pushed away from the wall, and an opposite flow arises downstream. This phenomenon is known as the boundary layer separation. A CFD models were simulated for the viscous flow past bodies changed from a circular cylinder to flat plate. FLUENT 6.3.26 package was used for solving the model preprocessed in GAMBIT 2.3.16 for flow past a body. Fluent solvers were based on the finite volume method and general conservation (transport) equation for momentum was discretized into algebraic equations. The pressure and velocity gradients for viscous flow past bodies changed from a circular cylinder to flat plate was predicted and plotted and the effect of eccentricity on the pressure and velocity gradients was studied.
Samir S. Mustafa
Volume 2, Issue 2 , June 2009, Pages 477-485
Abstract
Iraqi National Super Grid suffers from out of synchronism of the system due to short circuit in the lines. The main goal of this work is to study the effect of optimum generation and reconfiguration of some transmission paths on transient stability improvement for Iraqi Network in case of short circuit ...
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Iraqi National Super Grid suffers from out of synchronism of the system due to short circuit in the lines. The main goal of this work is to study the effect of optimum generation and reconfiguration of some transmission paths on transient stability improvement for Iraqi Network in case of short circuit in Haditha-Qaim line because it is one of the wrest lines. A programmable package build under Matlab5.3 was used to determine synchronous machines rotor angles as an indicator of transient stability. Sad Al-Mosul, Haditha and Nasiriya power plant were chosen to notice the situation of stability.
Mazin M. Ali
Volume 2, Issue 2 , June 2009, Pages 486-499
Abstract
A system of sixteen programmable drivers has been established around an 8085 microprocessor, where each driving path is independent and can be programmed to energize the driven element at the desired timing for the desired period of time . An input programming circuit of thirty programming steps is built ...
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A system of sixteen programmable drivers has been established around an 8085 microprocessor, where each driving path is independent and can be programmed to energize the driven element at the desired timing for the desired period of time . An input programming circuit of thirty programming steps is built to enter the driving sequence for selected driver that specified by the driver selector .
Samir S. Mustafa
Volume 2, Issue 2 , June 2009, Pages 500-513
Abstract
Iraqi super grid power system consists of six generating power plants : Baji, Sad Al-Mosul, Haditha, Mussayab, Nasiriya and Hartha. A Matlab5.3 package has been used to calculate the optimum generation of the system generators which gives minimum losses in comparison with the total losses according ...
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Iraqi super grid power system consists of six generating power plants : Baji, Sad Al-Mosul, Haditha, Mussayab, Nasiriya and Hartha. A Matlab5.3 package has been used to calculate the optimum generation of the system generators which gives minimum losses in comparison with the total losses according to the same data which were recorded in National Control Center. The losses reduction became 30.96% . Gradient method has been employed for the solution of optimal power flow. The partial derivative of active and reactive losses with respect to injected power were used as an indicator on optimum power generation.
Ali Abdul Razzaq Al - Tahir
Volume 2, Issue 2 , June 2009, Pages 514-531
Abstract
This work studies the effect of varying air-gap length on performance and behavior of electromechanical relays. When the air-gap length changed due to mechanical movement producing from air or liquid pressure in pneumatic or hydraulic system, respectively therefore; the magnetic reluctance is change, ...
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This work studies the effect of varying air-gap length on performance and behavior of electromechanical relays. When the air-gap length changed due to mechanical movement producing from air or liquid pressure in pneumatic or hydraulic system, respectively therefore; the magnetic reluctance is change, that is the inductive properties be effected and as a result of that, the switching value of voltage and current are changed drastically in electromechanical relays. It can be controlled on the min. and maximum value for air pressure in a pneumatic system by controlling on the minimum and maximum value corresponding to voltage and current in the system relay. Two models of transducers are used in this study; the first is variable reluctance displacement transducer studies the intensity of magnetic field lines in 2-D, the intensity of magnetic field vectors and summation of magnetic field intensity contours estimated. The magnetic force is determined with air- gap length changing from (0.8 to 0.2) cm, gradually. Second model is variable differential reluctance transducer. The same results obtained in first model are determined in second model with two cases, armature in mid-way and armature shifted to right side by (0.4) cm. The magnetic force is determined along the line of axisymmetric and in Y direction of armature location. The results show from ANSYS 5.3 and MATLAB - 7 - simulation, the magnetic field increases with decreases of air-gap length in first model and for the second model the magnetic field concentrated in mid - way armature position and increase in the side where the air - gap length reduced and reduced in the side where the air – gap length increasing.
Muhanad Dhiya Hashim
Volume 2, Issue 2 , June 2009, Pages 532-541
Abstract
In the industrial world the computers and microprocessors have become popular for use in automatic control systems, thus we have a new generation of control systems which is called Programmable Logic Controller . These systems has plenty of control components )Timers, Counters, Registers, Comparator, ...
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In the industrial world the computers and microprocessors have become popular for use in automatic control systems, thus we have a new generation of control systems which is called Programmable Logic Controller . These systems has plenty of control components )Timers, Counters, Registers, Comparator, Clock, …(inside the software of the PLC instead of the classical components , and the
contacts of the relay ) Normal open and Normal close ) have been replaced by the orders which are saved in memory. The updating and modification of the system is easy to obtain by rewriting the program.Another advantage of the PLC is that the input of the PLC is photo isolated and shielded , but the most important advantage is that we can test the program befor it's using in the machine by using the simulator which is included with the PLC program
