Amal Sadiq Atta; Nawres Jabar Nasse; Eklas Ahmad Abd-lrazaq
Volume 8, Issue 1 , March 2015, Pages 0-0
Abstract
This paper include studying the effect of adhesive wear of three groups which fabricated of 100% non-saturated polyester resin, 70% non-saturated polyester resin with 30% E -fiber glass, and the third was 70% non-saturated polyester resin with 30% carbon fiber.
Adhesive wear test have been conducted ...
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This paper include studying the effect of adhesive wear of three groups which fabricated of 100% non-saturated polyester resin, 70% non-saturated polyester resin with 30% E -fiber glass, and the third was 70% non-saturated polyester resin with 30% carbon fiber.
Adhesive wear test have been conducted on specimens which fabricated from material above according to ASTM G-99 in diminutions (10x10x25) at variable loads(5,10,15,17.5)N ,sliding speed (1.9, 3.79, 5.96) m/min and constant time (5) min using pin on disc method in dry condition at room temperature. Wear rate in the experiments was determined as weight loss.
The results show that the wear rate of composite specimens increase when the applied load and sliding speed for all types of composites increased. The wear characteristics improved by adding carbon fiber to polyester gives less wear rates compared with other types of composites for all loads and sliding speeds
Jassim Atiya Alwan
Volume 8, Issue 1 , March 2015, Pages 0-0
Abstract
The aim of this research is to prepare a site & laboratory studying to define the distresses and the pavement condition for one of the main roads in Hilla city by defining pavement distresses and their arising causes by standard American Pavement Condition Index (PCI) method without any Pavement laboratory ...
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The aim of this research is to prepare a site & laboratory studying to define the distresses and the pavement condition for one of the main roads in Hilla city by defining pavement distresses and their arising causes by standard American Pavement Condition Index (PCI) method without any Pavement laboratory tests and compare Pavement condition definition with the familiar classical method after executing different tests which is required much efforts & cost, also the research is including how to repair the arising distresses with the recent technics which have to be employed during road pavement design or at distresses repairing to decrease or to prevent their arising. (50) road sectors were required for one of the Asphaltic road directions with(5.0)km length,(7.0)m width and listing their different pavement distresses by site inspection using (PCI) method to find the pavement condition index (PCI) values for each sector to define the pavement sectors condition. A selection of (10) asphaltic samples by core test and another(10) samples of road pavement from same locations to execute different tests. The (PCI) method values results showed that (30) sectors are in fair conditions, (20) sections are poor and the pavement include (8) distresses from a (19) standard distresses in this method which is supported by test results of classical method for Pavement condition definition and its distresses arising due to bad site execution of road pavement layers, inefficient wearing course to resist traffic loads and these distresses should be repaired by spraying emulsion fog seal, adding sandy seal layer with fine gravel some times and removing with repaving wearing course in some locations
Saleh Alatawi
Volume 8, Issue 1 , March 2015, Pages 0-0
Abstract
This research is an exploratory and descriptive study of the variation orders, as one of the most important issues and variables acting in Saudi construction management. The researcher tried to achieve five objectives, Which are: identifying the main active stakeholders in the variation orders, to determine ...
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This research is an exploratory and descriptive study of the variation orders, as one of the most important issues and variables acting in Saudi construction management. The researcher tried to achieve five objectives, Which are: identifying the main active stakeholders in the variation orders, to determine to what extend they affect the variation orders, how the variation orders are priced, monitoring and identifying the most important activities that cause the variation orders, and to identify the most important aspects on how the variation orders affect the management of construction projects.
To achieve the objectives above, the researcher conducted a field study, which relied on a sample survey approach to obtain the required data. The researcher applied the field study using 256 samples from the field of governmental construction management.
The research found a number of results, of which:
• The owner of the project was in the first place as the stakeholder that starts the variation orders.
• Original contract item pricing is the most common way to calculate the value of the variation orders.
• To refrain from execution, while awaiting the written permitting comes in the first place, as a method of practice in the execution of variation orders.
• That the project's owner is the most effective stakeholder that makes the variation order executable.
• Architectural works are most common cases in which the variation orders are repeated in a manner that is greater than all the other cases
Qasim Abbas Atiyah
Volume 8, Issue 1 , March 2015, Pages 1-13
Abstract
Recently, Shape Memory Alloys (SMAs) has been on the forefront of research. SMAs are unique alloys in that they can remember an original shape after being deformed. They have been used for a wide variety of applications in various fields. The natural frequencies have been identified as one of the most ...
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Recently, Shape Memory Alloys (SMAs) has been on the forefront of research. SMAs are unique alloys in that they can remember an original shape after being deformed. They have been used for a wide variety of applications in various fields. The natural frequencies have been identified as one of the most critical parameter in vibration study which may lead to structure failure during resonance. In present work, an analytical solution for the calculation of natural frequencies of composite cantilever beams with embedded SMA wires was studied. The beams were clamped at one end and free in other end. A mathematical model is developed to describe the behavior of the natural frequencies of a cantilever composite beam embedded by SMA wires and solved by using Matlab program. The natural frequencies found from the analytical were compared with previous research and got a good agreement error. It was found that the natural frequencies of beams decreased with increasing the number of embedded SMA wires at a temperature below martensite temperature transformation and increased with increasing the number of embedded SMA wires at a temperature above austenite finish transformation. Some geometrical factors and mechanical properties were studied in this work, such as width of beam, thickness of beam, length of beam, diameters of SMA wires, modulus of elasticity of Glass fiber epoxy, and austenite ratio in SMA wires. Increasing these factors caused increasing in the natural frequencies of composite beam while the increase of length of beam resulted in decreasing in natural frequencies.
Muhanad Hamed Mosa
Volume 8, Issue 1 , March 2015, Pages 14-20
Abstract
In this paper, fatigue crack growth rate (FCGR) analyses were conducted on compact specimens of an AISI 4340 alloy to study the behavior over a range in load ratios (0.1 ≤ R ≤ 0.95) and constant maximum stress intensity factor (Kmax) condition. Previous study had indicated that high R > 0.7 and constant ...
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In this paper, fatigue crack growth rate (FCGR) analyses were conducted on compact specimens of an AISI 4340 alloy to study the behavior over a range in load ratios (0.1 ≤ R ≤ 0.95) and constant maximum stress intensity factor (Kmax) condition. Previous study had indicated that high R > 0.7 and constant Kmax test conditions near threshold conditions were suspected to be free crack-closure and that any differences were caused by Kmax effects, from threshold to near fracture conditions. Cracks in high-cycle fatigue (HCF) components spend a large portion of their fatigue life near threshold conditions. In order to characterize the evolution of damage and crack propagation during these conditions, fatigue crack growth rate (FCGR) data at threshold and near-threshold conditions are essential in predicting service life and in determining the proper inspection intervals. Fatigue crack growth model, namely Forman were examined, this model implicit the effect of R ratio and ease of curve fitting to measured data. The Forman model may be suggested for use in critical applications in studying fatigue crack growth for different load ratios.
Ali A. Jazie Al-Khaledy
Volume 8, Issue 1 , March 2015, Pages 21-37
Abstract
A bone waste was utilized as a cost effective catalyst for the transesterification of Indian mustard oil. This high efficient and low-cost waste catalyst could make the biodiesel production from Indian mustard oil competitive with petroleum diesel.The catalysts samples were calcined at different temperatures ...
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A bone waste was utilized as a cost effective catalyst for the transesterification of Indian mustard oil. This high efficient and low-cost waste catalyst could make the biodiesel production from Indian mustard oil competitive with petroleum diesel.The catalysts samples were calcined at different temperatures (800oC, 900oC and 1000oC) for 2 hrs. The samples were characterized by using X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and BET surface area analyzer. A simple model was used to study the kinetics of hydroxyapatite-catalyzed transesterification of mustard oil. The optimum conditions for biodiesel production were (reaction temperature (60oC), a methanol-to-oil molar ratio (20:1) and catalyst amounts (18% based on oil weight). Two steps were concluded for the transesterification process, the initial one is the triglyceride (TG) mass transfer controlled region, The second one is the chemical reaction controlled region. The high adsorbed methanol concentration and the lower availability of active specific catalyst surface caused the TG mass transfer controlled region.Increasing the catalyst amount in the transesterification process caused increasing both the TG mass transfer and chemical reaction rates.The effect of mixing conditionsin the transesterification process was predicted in the modeling strategy.
Ali Hameed Naser Al-Mamoori
Volume 8, Issue 1 , March 2015, Pages 38-58
Abstract
The region of a slab in the vicinity of a support could fail in shear by developing a failure surface in the form a truncated cone or pyramid. This type of failure, called "Punching Shear Failure", is usually the source of collapse of flat-plate and flat-slab structures. An experiment to be conducting ...
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The region of a slab in the vicinity of a support could fail in shear by developing a failure surface in the form a truncated cone or pyramid. This type of failure, called "Punching Shear Failure", is usually the source of collapse of flat-plate and flat-slab structures. An experiment to be conducting to investigate the punching shear strength and failure behavior of self concrete (SCC) slabs using carbon fiber reinforced polymer (CFRP) bars as internal strengthening in connection region for slab-column. Seven interior slab-column connections tested including same concrete compressive strength and ratio of the reinforcement. All slabs will be tested as a simply supported and subjected to punching loading by interior column. Test results show that the internal strengthening technique by using high tensile strength CFRP bars improves the bearing capacity of RC two-way slabs.
Based on the experimental results, it is possible to increase punching shear capacity by using internally reinforced with CFRP bars concentrated in slab-column zone, this increase is about (33-100%) compared with the unstrengthened (control) slab.
The effectiveness of the CFRP bars is depended substantially on distributed or arrangement manner in slab-column region.
Also, it is found that, the use of NSM CFRP bars is an effective technique to enhance shear capacity of SCC slab-column models and nearly provided the same efficiency of internal reinforcement.
Even efficient to increase the punching shear load, the top reinforcement of CFRP bars will not change the brittle-type punching shear failure mode compared with bottom CFRP bars reinforcement.
Haider Muhamed Umran
Volume 8, Issue 1 , March 2015, Pages 59-72
Abstract
The quality of an electrical power plays an important factor in any industrial process, these factors relate to the economic and technical benefits. The cement industry used many of the miscellaneous equipment's, which are classifying as non-linear loads such as induction motors, transformers and etc. ...
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The quality of an electrical power plays an important factor in any industrial process, these factors relate to the economic and technical benefits. The cement industry used many of the miscellaneous equipment's, which are classifying as non-linear loads such as induction motors, transformers and etc. The electrical equipment's are absorbing additional currents called "inductive reactive currents"; the effects of additional currents making electrical network inefficient, result of reducing the power factor. However, the low power factor will affect the increase the loads on the power station on the one hand and on the efficiency of the equipment's, capacity of transformer's, sizes of cables and capacity of switchgears on the other hand this in relation to the cement plant.
In this paper, the effects of low power factor on main motors which use in AL-Najaf cement plant analyzed, such as raw material mill, cement mill and the clinker cooler. The necessary reactive power for the capacitor bank calculated according to practical readings for equipment's information that printed on the name-plates, by using two methods for calculation (the mathematical equations and table of factor K). The influence of power factor correction on the motors, transformers and sizes and losses of electrical cables calculated. The advantages of power factor correction are analyzed for economic and technical sides.
Hayder A. M. Al-Hameedi
Volume 8, Issue 1 , March 2015, Pages 73-81
Abstract
In this study commercially pure aluminum sheets were welded using friction stir welding (FSW) process. Three rotational speeds of 800, 1100 and 1500 rpm were used. The axial force, passing speed, and tool geometry were constant. Parameters were optimized depending on the results of the macrograph, micrographic, ...
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In this study commercially pure aluminum sheets were welded using friction stir welding (FSW) process. Three rotational speeds of 800, 1100 and 1500 rpm were used. The axial force, passing speed, and tool geometry were constant. Parameters were optimized depending on the results of the macrograph, micrographic, microhardness, and tensile strength. The results showed that the sound joint with the best possible microstructure and mechanical properties was obtained at a rotational speed of 1100 rpm. The microscopic and local mechanical properties proposed that mechanical mixing is the main material flow mechanism in the formation of the nugget zone (NZ).
Abbas Jassem Jubear
Volume 8, Issue 1 , March 2015, Pages 82-98
Abstract
This study aims to perform an experimental study of heat transfer by forced convection for three cylinders (with 12 triangular, rectangular shape fins and without fins) made of aluminum. The inner and outer diameters of these cylinders considered in this study ware (16 mm) and (48 mm) respectively .The ...
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This study aims to perform an experimental study of heat transfer by forced convection for three cylinders (with 12 triangular, rectangular shape fins and without fins) made of aluminum. The inner and outer diameters of these cylinders considered in this study ware (16 mm) and (48 mm) respectively .The study has been performed for different,geometry, slope angles (0°-45°) and range of air velocities (0.5-4m/s). The three cylinders ware heated by a constant heat flux generated by passing an alternative current (AC) through a resistance placed inside the internal space for each cylinder . The effects of air velocity , inclined angle and geometry of fins have been studied in this study for a range of heat fluxs (13-247) W. The results show that the rate of heat transfer increases as the air velocity increases but it decreases with increasing inclined angle. The heat transfer coefficient increases generally with increasing Reynolds number (Re) and the heat transferred from triangular test sample (12) fins is greater than that from rectangular test sample and without fin type. An empirical relationships between Reynolds number (Re) and Nusselt number (Nu) is concluded:
Test sample (12) fins with triangular section : Nu=0.02474 Re^0.939
Test sample (12) fins with rectangular section: Nu=0.047 Re^0.8353
Test sample without fins Nu=0.06 Re^0.71
