Ahmed Mudhaffer Hashim
Volume 3, Issue 2 , June 2010, Pages 0-0
Abstract
In this paper presents the flexural properties of composites made from natural fibers (Coir fibers) as reinforcing phase in polyester matrix. The chemical treated of fibers with KOH solution at different concentrations (1, 5, 10 % KOH) with different times (0.25, 1, 18, 72, 168, 240 Hours) are used. ...
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In this paper presents the flexural properties of composites made from natural fibers (Coir fibers) as reinforcing phase in polyester matrix. The chemical treated of fibers with KOH solution at different concentrations (1, 5, 10 % KOH) with different times (0.25, 1, 18, 72, 168, 240 Hours) are used. Flexural strength reached the maximum values of (2.81 MPa) at immersed time (18 Hours) with (10 % KOH) concentration, whereas the composites containing fibers treated with (10 % KOH) decreased to (0.312 MPa) at immersed time (240 Hours). This was attributed to degradation of coir fiber when using high concentrations of alkali.
Hamdi E. Ahmed Hamdi
Volume 3, Issue 2 , June 2010, Pages 0-0
Abstract
A Theoretical study has been conducted on the influence of Semi-tube orientation on combined free and forced laminar convection heat transfer where the Semi-tube heated with constant surface temperature. The theoretical study was done for both the thermal entrance region and hydraulically fully developed ...
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A Theoretical study has been conducted on the influence of Semi-tube orientation on combined free and forced laminar convection heat transfer where the Semi-tube heated with constant surface temperature. The theoretical study was done for both the thermal entrance region and hydraulically fully developed region.
Theoretically the governing equations for a flow through an inclined Semi-tube were reduced to four, which are continuity equation, radial and tangential momentum equations, axial momentum equation and vorticity equation in which the variables where the temperature, vorticity, stream function and axial velocity. These equations were reduced to dimensionless equations in which Grashof, Prandtl, Reynolds and Rayleigh numbers were presented. These equations were numerically solved by using the marching process explicit finite difference method and Gauss elimination technique. Numerical results for the inclined Semi-tube heated by constant surface temperature in the thermal entrance region were obtained and represented by stream function contours and isotherms for different values of Rayleigh and channel angle, as well as the circumferential distribution of local Nusselt number and the change of average Nusselt number with Rayleigh number. The results clarify the significant effects of the secondary flow created by natural convection on the heat transfer process, reveal an increase in the Nusselt number as the angle of inclination moves from the vertical to the horizontal position.
Salih Abbas H.Al-Juthery; Dr.Mohammed H.Al-Maamory
Volume 3, Issue 2 , June 2010, Pages 0-0
Abstract
This research is aimed to study the effect addition of Borax on Vulcanization properties of Rubber. which is represented by Viscosity , Elasticity,Plasticity which is defined as Rheology where suitable Quantities from Borax powder with loading level (0,5,10,15,20 pphr) were added to suitable type ...
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This research is aimed to study the effect addition of Borax on Vulcanization properties of Rubber. which is represented by Viscosity , Elasticity,Plasticity which is defined as Rheology where suitable Quantities from Borax powder with loading level (0,5,10,15,20 pphr) were added to suitable type of Rubber (styrene- Butadiene Rubber, Nitrile Rubber ,and poly Chloroprene type (WRT)) and notice the change in Scorch time and this perioed time which is limited the Resistance of Rubber Compounds to Vulcaniztion and Occurrence at Min. point of Viscosity and Curing time which is Limited the Perioed time for Ending the Vulcaniztion Process and Occurrence at atopmost point for Viscosity after addition of Borax to Rubber Compounds and which has been check that the addition Borax powder which is discrease the Viscosity of (SBR ) Rubber and Increase the Viscosity of (NBR) Rubber and Increase the viscosity of (WRT) Rubber for point (10pphr)
Majeed Mattar Ramal
Volume 3, Issue 2 , June 2010, Pages 33-56
Abstract
This research evaluate the drinking water quality of The large treatment plant in the RAMADI city at AL-ANBAR Province .The water samples were taken from which The Intake (Raw Water- Euphrates), The Pumps Unit after Chlorination (Drinking water),. The Concentration of some Characteristics such as physical, ...
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This research evaluate the drinking water quality of The large treatment plant in the RAMADI city at AL-ANBAR Province .The water samples were taken from which The Intake (Raw Water- Euphrates), The Pumps Unit after Chlorination (Drinking water),. The Concentration of some Characteristics such as physical, Chemical and Biological (Bacteriological) Have been calculated. The samples have been taken twice in the month (average of three samples) for one year, to evaluate the drinking water quality and efficiency of the large water treatment plant in the RAMADI. the results show that the Ramadi drinking water quality, drinking water has mean (PH) value of (7.6),mean turbidity of(5 NTU), mean electrical conductivity of (1226 μohms/cm), mean alkalinity of (119 mg/l), mean total hardness of (394 mg/l),mean calcium cation concentration of (49.6 mg/l), mean magnesium cation concentration of (38.4 mg/l), mean chloride anion concentration of (197.5 mg/l), mean Sulphate concentration of (347 mg/l), mean total dissolved solids concentration of (889 mg/l), mean total suspended solids concentration of (24.2 mg/l), mean sodium cation concentration of (130 mg/l), mean potassium cation concentration of (4.9 mg/l), mean nitrate concentration of (3 mg/l),which within local and national standard limitations except the Sulphate (SO4), Turbidity and electrical conductivity which more than the local and national standard limitations, Although, the raw water has good physical and chemical water quality characteristics but, highly polluted with bacteria, drinking water was free from both Coliform bacteria and (E-coli),while has about (2 cells) of total plat count of bacteria . there are many essential problems in the plant, no significant change could be detected in raw and treated water quality. Because of, the maintenance is rarely practiced in time, In addition, the addition of lime is not applied in practice because of the operators thought that the low turbidity water not need lime ,lime not added when turbidity (equal or less than 5NTU). A study for each unit of plant was applied to collect the data and Concentration of some Characteristics such as physical, Chemical have been calculated to determine the problem in the plant. Settling column experiment has been carried to determine the sedimentation tank removal efficiency, the sedimentation units has about (36%)removal efficiency, which is must be (70%-90%) ,the filtration units has about(23.4%) removal efficiency and the disinfection stage has about (97% - 100%) disinfection efficiency, which are within the Iraqi standard limitations and world health organization. (STATICA) descriptive statistical analysis program has been used to perform the required statistical analysis for the data. this program used to find some statistical distribution for water quality characteristics . Each set of data represents an operation period of one month. It was found that data were generally symmetrical and were skewed to the mean values, as measured by the Skewness coefficient .which means good distribution about mean value.
Amer Mustafa Rasheed
Volume 3, Issue 2 , June 2010, Pages 57-75
Abstract
The aim of this research is to study the effect of water absorption on the fatigue property. This is to be done for materials that made from polyester resin reinforce by carbon fibers.This material has been prepared in the laboratory as sheets with two different percentages of fiber carbon contents ...
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The aim of this research is to study the effect of water absorption on the fatigue property. This is to be done for materials that made from polyester resin reinforce by carbon fibers.This material has been prepared in the laboratory as sheets with two different percentages of fiber carbon contents , These percentages are 5% and 8% . Then a specimens have been prepared in a shape and size that convenient to suit the fatigue test machine . These specimens has been weighted before and after immersed in water for (15) days. The weight of the specimens have been checked every (24) hours in order to know the water absorption at room temperature (32) c0 .Then a fatigue tests have been carried out for two types of specimens , These specimens are dry and wet specimens .
Waseem H. Mahdi; Hayder T. Nimnim
Volume 3, Issue 2 , June 2010, Pages 122-147
Abstract
In this paper, a theoretical analysis is presented for estimating the in-plane large displacement elastic-plastic behavior of steel frames having members resting on elastic foundation subjected to either proportional or non- proportional increasing static loads and including shear deformation effect. ...
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In this paper, a theoretical analysis is presented for estimating the in-plane large displacement elastic-plastic behavior of steel frames having members resting on elastic foundation subjected to either proportional or non- proportional increasing static loads and including shear deformation effect. The analysis adopts the beam- column approach and models the structure’s members as beam-column elements. The formulation of the beam- column element is based on Eulerian approach allowing for the influence of the axial force on bending stiffness. Also, changing in member chord length due to axial deformation, flexural bowing and shear deformation effect are taken into account. The formation of tangent stiffness matrix for the member in local and global coordinates with geometric and material nonlinearly including shear effect have been presented. In a special procedure, the calculation of axial force and plastic moment capacity including shear effect has been explained. New interaction equations between the axial force, shear force and plastic moment capacity for box and I-steel sections are presented in this study. The present search has adopted the linear and nonlinear behaviors of soil and these behaviors have been presented by isolated springs at the nodes. The computational technique utilizes an incremental load approach with a Newton-Raphson iteration to satisfy joint equilibrium equations. In order to verify the efficiency of the present formulation, some case studies reported by previous researches are utilized. The investigation is extended to study the effect of shear deformation on the elastic plastic behavior of structures resting on elastic foundation. As a result of this investigation, several important conclusions are obtained, which assure the necessity of taking into account the shear effect in the analysis of large displacement elastic-plastic behavior of structures resting on elastic foundation.
Latef Numan; Asst. Lec. Hesham Abd AL
Volume 3, Issue 2 , June 2010, Pages 148-160
Abstract
The present study is an experimental comparison between the effect of increasing the compressive strength of the section and increasing the reinforcement ratio on the results of strengthening reinforced concrete beams with external steel plates of constant dimensions.
The experimental program consists ...
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The present study is an experimental comparison between the effect of increasing the compressive strength of the section and increasing the reinforcement ratio on the results of strengthening reinforced concrete beams with external steel plates of constant dimensions.
The experimental program consists of testing ten reinforced concrete beams. Five of them are without external steel plates to be the original specimens while the other five ones are provided with steel plates of same dimensions glued at the bottom face of the beams.
Three values of compressive strength (f'c) were used in this study which were (22, 45 and 71MPa) and also three ratios of internal reinforcement (ρ) which were (0.01411, 0.02116 and 0.03445) to investigate their effects on the strengthened beams behavior.
The results showed that the cracking load and the ultimate load can be increased up to (150% and 137%) respectively. Also, by increasing the section compressive strength all the properties of the strengthened beam can be improved while by increasing the reinforcement ratio the deflection and cracking can be reduced to improve the elastic behavior of the beam.
Mohammed Ghanem Jehad
Volume 3, Issue 2 , June 2010, Pages 161-172
Abstract
. Friction factors for fully developed flow in an equilateral triangular duct containing built-in vortex generators of delta wing, rectangular wing, pair of delta winglets, and pair of rectangular winglets have been investigated experimentally for Reynolds numbers ranging from (24 500) to (75 750). The ...
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. Friction factors for fully developed flow in an equilateral triangular duct containing built-in vortex generators of delta wing, rectangular wing, pair of delta winglets, and pair of rectangular winglets have been investigated experimentally for Reynolds numbers ranging from (24 500) to (75 750). The ratio of the cross- sectional area of the test duct to that of the vortex generator (AD/AVG) was remaining constant during experiments. The variable parameters were; type of vortex generator, vortex generator angle of attack, and Reynolds number. The friction factor values for the smooth triangular duct are in good agreement with the existing data. The present results show that the friction factor is affected strongly by the wing greater than the winglet pair of vortex generators. The delta wing causes flow loss greater than the rectangular wing, while the flow loss accompany with the existence of the pair of delta- winglets is less than that of the pair of rectangular winglet. It is also observed that the friction factor is affected remarkably by the angle of attack of vortex generator.
Mahdi Hatf Kadhum
Volume 3, Issue 2 , June 2010, Pages 173-191
Abstract
The performance of a distillator in a double – cycle distillation heat pump system, utilizing water as a working fluid in finned tube heat exchangers for evaporator and condenser, has been investigated. A mathematical model was set for the whole system and a simulating program was developed to simulate ...
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The performance of a distillator in a double – cycle distillation heat pump system, utilizing water as a working fluid in finned tube heat exchangers for evaporator and condenser, has been investigated. A mathematical model was set for the whole system and a simulating program was developed to simulate the double – cycle processes during the steady – state operation. This subroutine program to calculate the water and steam properties in the range of (65 – 115)oC and (0.25 – 1.6906)bar.The experimental results showed good agreement with the results obtained from the computer program. The concentration on the distillator performance during steady – state operation of the system is occurred, and it was found that the distillator performance (COPdist.) increased when the working mass flow rate increased and also it was increased when the working fluid pressure increased and had a maximum value (83.3%) at working mass flow rate of 5.5 kg/hr, working fluid pressure of 0.8 bar and process fluid pressure of 1.01825 bar.
Zainab Talib Abidzaid al-Sharify
Volume 3, Issue 2 , June 2010, Pages 192-212
Abstract
Fluidization process is widely used by a great assortment of industries worldwide; one of these processes is the mass transfer from an immersed body to a fluidized gas bed. This work presents an experimental study of a continuous gas-solid fluidized bed with a porous material placed at the bottom of ...
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Fluidization process is widely used by a great assortment of industries worldwide; one of these processes is the mass transfer from an immersed body to a fluidized gas bed. This work presents an experimental study of a continuous gas-solid fluidized bed with a porous material placed at the bottom of the column to support the packing material. Sand-air-naphthalene system has been used in this work. Sand with sizes distributed between 75-250 microns was used as solid fluidizing particles and air was used for fluidization in a 70 cm height and 8 cm inside diameter fluidization Column. Naphthalene was selected for this study as the immersed object, this have been done by making a spheres of wood of 2.9 cm outside diameter and coating this spheres wood with Naphthalene by dipping this spheres into a bath of molten naphthalene (at about 900C). An empirical correlation was developed for mass transfer of naphthalene vapor into air-sand fluidized bed by using experimental data of many variables such as temperature, air velocity, and sand particle size. The experimental results of the mass transfer in the present work have been compared in curve in Yokota,s coordinate with many documented experimental literatures data. The comparison gave a very good agreement, and show that Sherwood number increased slowly with the increase in gas velocity at constant surface temperature and particle size.
Samir Abdul Cathem Khother; Haider jabber abd
Volume 3, Issue 2 , June 2010, Pages 213-221
Abstract
This search describes an iterative decoding of product code using Soft Input Soft Output Maximum Likelihood (SISO ML) decoder. The SISO ML decoder is implementing using Pyndiah's algorithm where the soft output of decoder is an estimation of the log likelihood ratio (LLR) of the binary decision of ML-decoder. ...
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This search describes an iterative decoding of product code using Soft Input Soft Output Maximum Likelihood (SISO ML) decoder. The SISO ML decoder is implementing using Pyndiah's algorithm where the soft output of decoder is an estimation of the log likelihood ratio (LLR) of the binary decision of ML-decoder. The theoretical justification of this algorithm is developed, and the method used for computing the soft output is fully described. Then the implementation of iterative decoder of product codes (turbo product codes) is described.Simulation results (using MATLAB program version 7 ) of turbo product codes are presented. The simulation process includes different cases. These result shows that powerful BER performance could be achieved by using block codes with large code length, and BER performance depends mainly on minimum Hamming distance of the outer code. These results also compare between conventional ML decoder and iterative ML decoder and show the powerful BER performance of iterative decoder at low SNR, that make it used in deep space communication
