Yassar K. Al- ansari
Volume 2, Issue 1 , March 2009, Pages 0-0
Abstract
The soot (solid carbon particles) emitted from diesel engines into atmosphere is to consider one of dangerous pollutant because it is easy inhaled deep into the lungs and some polycyclic aromatic hydrocarbons known for their cancer properties are associated with it. The direct gravimetric method is used ...
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The soot (solid carbon particles) emitted from diesel engines into atmosphere is to consider one of dangerous pollutant because it is easy inhaled deep into the lungs and some polycyclic aromatic hydrocarbons known for their cancer properties are associated with it. The direct gravimetric method is used to measure the soot mass rate. The soot particles through the exhaust pipe are trapped using Pyrex-glass collecting piece with glass wool filter. The rate of soot mass emitted and brake power are expressed in (g/kw hr) unit. The variation of soot mass with engine load is compared with U. S. Environmental Protection Agency (EPA) standards. It is found as the engine load is increased, the rate of soot mass increases and exceeds the (EPA) standards in the first tier. The high rate of soot mass causes strong decrease in the brake power and thermal efficiency. The soot usually burns at the temperature of 600 Co approximately. The results show that the high soot mass in high load can be treated by raising the exhaust temperature and reached to greater than 600Co. In the moderate load up to 70%, it is found that the soot mass emitted is not exceeding the (EPA) standards in the first and second tiers. The exhaust temperature is high and the soot mass rate is to be low and easily treated.
Hayder Shakir Abdulla
Volume 2, Issue 1 , March 2009, Pages 0-0
Abstract
The entropy generation method is applied to measure the thermodynamic losses caused by heat transfer and pressure drop in cylindrical pin-fin heat sinks which cooled by impingement air flow. The use of this method allows the combined effect of thermal resistance and pressure drop to be assessed through ...
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The entropy generation method is applied to measure the thermodynamic losses caused by heat transfer and pressure drop in cylindrical pin-fin heat sinks which cooled by impingement air flow. The use of this method allows the combined effect of thermal resistance and pressure drop to be assessed through the simultaneous interaction with the heat sink. A general expression for the entropy generation rate is obtained by considering the whole heat sink as a control volume and applying the conservation equations for mass and energy with the entropy balance. Analytical and empirical correlations for heat transfer coefficients and friction factors are used in the optimization model, where a new characteristic lengths are used and reference velocity used in Reynolds number and pressure drop. The SUMT method is used to optimize the model which use the directional derivative to reach the minimum value to the objective function which is the entropy generation rate in this research. The language is used to programming the optimization procedure to the objective function and its constraints which is taken from the general electronic package case. The design is performed on the electronic circuit of thickness which is generate in the 300K ambient temperature. A comparison between the results and the results of the horizontal cooling is accomplished for the different air velociti
Ali I.Al-Mosawi
Volume 2, Issue 1 , March 2009, Pages 0-0
Abstract
The objective of this research is to study the effect of changing the reinforcement percentage by fibers on Mechanical properties, for composite material consists of conbextra epoxy (EP-10) resin reinforced by biaxial woven roving kevlar fibers (°45-°0) with density (340 g/cm3) which included impact ...
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The objective of this research is to study the effect of changing the reinforcement percentage by fibers on Mechanical properties, for composite material consists of conbextra epoxy (EP-10) resin reinforced by biaxial woven roving kevlar fibers (°45-°0) with density (340 g/cm3) which included impact strength , tensile strength , flexural strength and hardness Where the Mechanical properties were extracted for phenol formaldehyde resin before reinforcement by fibers, then we reinforced the resin by different weight percentage from Kevlar fibers(20%,40%,60%) and studied the effect on the above mechanical properties as illustrated in the diagrams .
Haider K. Ammash; Nameer A. Alwash; Husain M. Husain
Volume 2, Issue 1 , March 2009, Pages 1-21
Abstract
A nonlinear finite element method is adopted for the large displacement elastic-plastic static analysis of anisotropic plates under in-plane compressive loads. The analysis is based on the two-dimensional layered approach with classical and higher order shear deformation theory with five, seven, and ...
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A nonlinear finite element method is adopted for the large displacement elastic-plastic static analysis of anisotropic plates under in-plane compressive loads. The analysis is based on the two-dimensional layered approach with classical and higher order shear deformation theory with five, seven, and nine degrees of freedom per node. Nine-node Lagrangian isoparametric quadrilateral elements are used for the discretization of the laminated plates. Effects of orthotropy of individual layers, through-thickness shear deformation, fiber،¦s orientation angle, and fiber waviness on the large displacement elastic-plastic static analysis are considered. The plate is analyzed with a range of number of sequences (k) of sine wave fiber (1-12) and with a range of the amplitude of fiber path (ƒ´) of sine wave fiber (0.0-0.5). The conclusion it is shown that the behavior of the laminated plate is very sensitive to the shape of fibers (straight or sine wave), also the behavior of the plate with sine wave fiber depends on the amplitude of the fiber and the number of sequences of the fiber, and so the capacity of the laminated plate with sine wave fiber and under in-plane compressive load in the direction of waviness is higher than the capacity of the plate with sine wave fiber and under in-plane compressive load orthogonal to the direction of waviness by approximate value (42%).Keyword: Large Displacement, elastic-plastic analysis, finite element method, composite plate, in-plane compressive loads.
Qusay A. Jabal
Volume 2, Issue 1 , March 2009, Pages 22-30
Abstract
High strength concrete is widely used especially during the last century. High Strength concrete means concrete with max. Compressive strength ( )more than 50 N/mm2 (Shetty, 1988). Polymer modified concrete was) used since 1970s by adding polymer monomers such as styrene Butadiene rubber (SBR) ...
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High strength concrete is widely used especially during the last century. High Strength concrete means concrete with max. Compressive strength ( )more than 50 N/mm2 (Shetty, 1988). Polymer modified concrete was) used since 1970s by adding polymer monomers such as styrene Butadiene rubber (SBR) to ordinary concrete during casting as a percentage of weight of cement in order to improve the mechanical properties of concrete.This research includes the study of the effect of styrene Butadiene Rubber on Tensile Strength of Polymer modified concrete PMC, also include the effect of the polymer on compressive strength and relationship between tensile and compressive strength (as a mathematical model). A different types of mixes (1: 1.5: 2, 1:1.5:3 and 1:2:4) were used in this research.
Ali Hasson Nahhab
Volume 2, Issue 1 , March 2009, Pages 31-37
Abstract
This research produces a new results about using of locally available reed fibers in concrete. The main parameter of this study was the volume fraction of fibers. The reed fibers were added to the mix in percentages of 1, 2, 3, 4,and 6%. The test program included: slump, compressive strength, splitting ...
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This research produces a new results about using of locally available reed fibers in concrete. The main parameter of this study was the volume fraction of fibers. The reed fibers were added to the mix in percentages of 1, 2, 3, 4,and 6%. The test program included: slump, compressive strength, splitting tensile strength and impact resistance. It was found that the presence of reed fibers leads to reduce workability, compressive, splitting tensile and impact strength. It was also found that, generally, this reduction increases as the volume percentage of fibers is increased.
Salam Kh. Abdullah; Zaidun Naji Abudi; Ahmed H. Ali
Volume 2, Issue 1 , March 2009, Pages 38-44
Abstract
Many different media are used and operated by batch system to study the effect of using to reduce the heavy metals (lead, chrome and copper) ions from polluted water .The media used in this study are cone powder of corn, pinnulace corn and granular activated carbon. Many tests are conducted in these ...
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Many different media are used and operated by batch system to study the effect of using to reduce the heavy metals (lead, chrome and copper) ions from polluted water .The media used in this study are cone powder of corn, pinnulace corn and granular activated carbon. Many tests are conducted in these experiments to reduce these ions through various dosage of media with fixed the other conditions (mixing time, pH, volume of solution and speed of mixing). The concentration of the metals in solution where measured before and after the treatment by atomic absorption spectrophotometer. The removal efficiency of the three ions (Pb, Cr and Cu) are (93.0, 78.0 and 71.2)%, respectively with pinnulace corn, (87.4, 61.4 and 64.8 )% respectively with powder of corn and (98.3, 96.5 and 96.8)% respectively with granular activated carbon (GAC), with higher dosage for each media. These results show the ability of cone powder of corn and pinnulace corn to reduce the heavy metals from industrial waste water.
Ehab Abdul-Razaq Husain; Saad Saffah Hassoon
Volume 2, Issue 1 , March 2009, Pages 45-57
Abstract
In this paper, a new wideband direction-of-arrival (DOA) estimation method is proposed, related to the real time capability of DOA estimator the complexity estimation of the algorithms is used. This includes the calculation of different algorithms complexity and its applicability, taking into account ...
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In this paper, a new wideband direction-of-arrival (DOA) estimation method is proposed, related to the real time capability of DOA estimator the complexity estimation of the algorithms is used. This includes the calculation of different algorithms complexity and its applicability, taking into account frame and slot times, minimum number of samples and estimation bandwidth. The complexity of the algorithms as a function of key parameters is used. Based on these estimated functions, the execution time of the algorithms was calculated. Through the use of MATLAB package, which is used as reference for the calculation a DSP system with 400 MFLOPS processing power. Most algorithms can be executed within 400 µs. It’s provided also a method of two step estimation for further reduction of the execution time. Through this approach, a significant reduction was achieved for some combination of algorithms
Hanan A. R. Akkar
Volume 2, Issue 1 , March 2009, Pages 58-65
Abstract
In this paper a proposed design of five multi-layer feed-forward Artificial Neural Networks (ANNs) is presented for optimized Butterworth filter. The first and second network perform Butterworth ideal Low Pass Filter (LPF) and typical LPF. The third ANN performs Band Pass Filter (BPF). The fourth network ...
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In this paper a proposed design of five multi-layer feed-forward Artificial Neural Networks (ANNs) is presented for optimized Butterworth filter. The first and second network perform Butterworth ideal Low Pass Filter (LPF) and typical LPF. The third ANN performs Band Pass Filter (BPF). The fourth network perform multi–BPF which consists of two layers, the first layer consists of six tansig neurons and the second layer consists of one purline neuron, and the fifth feed-forward network is designed to perform the High Pass Filter (HPF) which consists of three layers, the first layer consists of three tansig neurons, the second layer consists of three tansig neurons and the third layer consists of one purline neuron. Back-propagation training algorithm is used to train the proposed networks with Mean Square Error (MSE) equals 10-10. Simulation and test programs are implemented by using MATLAB
Mazin M. Ali
Volume 2, Issue 1 , March 2009, Pages 66-73
Abstract
The probability density function of a-Si, taking into consideration presence of dangling bonds with correlation effect, is derived . The effects of temperature, trap level positions, free carriers concentrations and ratio of capture cross sections on the probability density function have been studied ...
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The probability density function of a-Si, taking into consideration presence of dangling bonds with correlation effect, is derived . The effects of temperature, trap level positions, free carriers concentrations and ratio of capture cross sections on the probability density function have been studied with respect to various positions of donor like and acceptor like trap levels, where it is found by MATLAB that variation of position of acceptor like trap level divides the curve of probability within air gap into three sublevels of values one, zero and the third has values in between. These sublevels have been affected by increasing the temperature of a-Si wafer, changing the concentration of free carriers and position of donor like trap level, while changing of ratio of capture cross section has no effect on the distribution of probability density function
Rehab Noor Mohammed Al-Kaby
Volume 2, Issue 1 , March 2009, Pages 74-93
Abstract
A mathematical model for the unsteady state heat and mass transfer in regenerative rotary heat exchanger is derived and solved numerically by using finite difference method. Triangular shape of the rotary matrix with silica gel (SiO2) that used as desiccant material is taken here. The heat transfer coefficient ...
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A mathematical model for the unsteady state heat and mass transfer in regenerative rotary heat exchanger is derived and solved numerically by using finite difference method. Triangular shape of the rotary matrix with silica gel (SiO2) that used as desiccant material is taken here. The heat transfer coefficient and the mass transfer coefficient that used in the present study are suitable for different types of the matrix shapes. The unsteady state time effect, inlet air temperature, Number of Transfer Unit (NTUt), heat exchanger length, inlet air temperature and the desiccant material volume on the latent, sensible and total effectiveness are discussed. It has been notes that the increasing of the heat exchanger length, inlet air temperature, desiccant material volume and the (NTUt) will increase the sensible, latent and total effectiveness. The increasing of the inlet air mass flow rate will decrease the total, latent and sensible effectiveness. The steady state time for the latent effectiveness is lower than the steady state time for the sensible and total effectiveness.
