Print ISSN: 1813-0526

Online ISSN: 2220-1270

Volume 20, Issue 1

Volume 20, Issue 1, Winter and Spring 2012, Page 1-132


Evaluating and Comparing of a Diesel Engine Performance and Its Pollutants Operating on Blends of Sunflower and Soybean Biodiesel Fuel

Arkan M. A. Sedeeq; Adil Abdulah; Firas S. Al-khayatt

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 1-9
DOI: 10.33899/rengj.2012.47210

Abstract
This study eventuated in two stages, the first is to extract biodiesel fuel from crude vegetable oil of sunflower and soybean oils, and the second stage is to use these extracted fuels to operate diesel engine. Three types of fuel used, the first fuel is conventional diesel fuels for comparison, the second and third types of fuel consist of four blends (B25, B50, B75, B100) for each type of sunflower and soybean biodiesel fuels. The fuels were used in the engine to find the criteria of performance of the engine which includes(Torque, Brake power, Specific fuel consumption) and discovers in the combustion products on (O2, CO, NO, CO2) for each type of fuel. The result of this study shows that the maximum performance of the engine is reached when the conventional diesel fuel is used, but increased the pollutants in atmosphere. The use of biodiesel fuel in the engine decreases the performance of the engine, but it will decrease emitting of (CO2, CO) and increase(NO) comparing with conventional diesel fuel. The results show decrease 31.9% in engine power when use the fuel (B100-SF) and decrease 18.2% of CO2 comparing with conventional diesel fuel. The fuel(B100-SB) shows decrease 33.7% in engine power and decrease 38.6% of CO2 when comparing with conventional diesel fuel. In addition the blends (B25-SF, B50-SF, B75-SF) give better engine performance and less pollutants emission when comparing with identical blends of fuel (B25-SB, B50-SB, B75-SB

Evaluating and Comparing of a Diesel Engine Performance and Its Pollutants Operating on Blends of Sunflower and Soybean Biodiesel Fuel

Arkan M. A. Sedeeq; Adil Abdulah; Firas S. Al-khayatt

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 1-9
DOI: 10.33899/rengj.2012.47223

Abstract
This study eventuated in two stages, the first is to extract biodiesel fuel from crude vegetable oil of sunflower and soybean oils, and the second stage is to use these extracted fuels to operate diesel engine. Three types of fuel used, the first fuel is conventional diesel fuels for comparison, the second and third types of fuel consist of four blends (B25, B50, B75, B100) for each type of sunflower and soybean biodiesel fuels. The fuels were used in the engine to find the criteria of performance of the engine which includes(Torque, Brake power, Specific fuel consumption) and discovers in the combustion products on (O2, CO, NO, CO2) for each type of fuel. The result of this study shows that the maximum performance of the engine is reached when the conventional diesel fuel is used, but increased the pollutants in atmosphere. The use of biodiesel fuel in the engine decreases the performance of the engine, but it will decrease emitting of (CO2, CO) and increase(NO) comparing with conventional diesel fuel. The results show decrease 31.9% in engine power when use the fuel (B100-SF) and decrease 18.2% of CO2 comparing with conventional diesel fuel. The fuel(B100-SB) shows decrease 33.7% in engine power and decrease 38.6% of CO2 when comparing with conventional diesel fuel. In addition the blends (B25-SF, B50-SF, B75-SF) give better engine performance and less pollutants emission when comparing with identical blends of fuel (B25-SB, B50-SB, B75-SB).

Design and Realization of Bireciprocal Lattice Wave Discrete Wavelet Filter Banks

Jassim M. Abdul-Jabbar; Sama N. M. Al-Faydi

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 1-14
DOI: 10.33899/rengj.2012.47144

Abstract
In this paper,designs and efficient realizations of special types of IIR wavelet filter banks are introduced. These special typesare the bireciprocal lattice wave discrete wavelet filter banks (BLW-DWFBs). It is believed that these IIR filter banks possess superior band discriminations and perfect roll-off frequency characteristics with respect to their FIR counterparts. 5th and 7th order bireciprocal lattice wavedigitalfilters (BLWDFs) are first derived. They are designed to simulate scaling and wavelet functions of six-level wavelet transform. Such IIR filter banks are then realized as all-pass sections. Computationally-efficient realizations by such sections indicate that the resulting IIR discrete wavelet filter banks canlead to hardware implementations with less-complexity.

Keywords:All-Pass Sections, Bireciprocal Lattice Wave Filters (BLWDFs), Bireciprocal Lattice Wave Digital Discrete Wavelet Filter Banks (BLW-DWFBs), IIR Wavelet Filter Banks, Scaling And Wavelet Functions.

Effect of size, shape and distribution of surface defects on the forming of aluminum sheet

Ahmed Nafie Rashid

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 10-19
DOI: 10.33899/rengj.2012.47229

The research was conducted on samples of aluminum sheet with 1 mm thickness, annealed at (275 C˚). To examine the effect of the size of surface defects on the stretch forming by introducing defects of different sizes on the surface of the sheet before forming process .Then forming the samples using a hemispherical punch without lubrication up to the fracture point. It was found that the defects size have a big effect on the fracture initiation and its propagation. The same result was found for the defect shape. Also the defect distribution was studied, where the defects distribution shows big effect on fracture position, which gave a clear picture of the forming is concentrated. Giving the opportunity to control forming and reduce the fracture.

Keywords: Aluminum, Stretch forming, Surface defects

FPGA Implementations of Single-Multiplier Digital Sine-Cosine Wave Generators

Jassim M. Abdul-Jabbar; Noor N. Qaqos; and

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 15-26
DOI: 10.33899/rengj.2012.47147

Abstract
This paper presents four different realizations of single-multiplier sine-cosine generators based on second-order digital filter structure. FPGA implementations of these four realizations are carried out on FPGA Spartan-3E Kit. Implementation results are comparedfrom the view points of utilization resources and maximum frequency of operation. Another comparison is made between one of implementations of the derived structures and other two recent CORDIC-based implementations. The comparison results indicate that smaller chip area can be achieved in the case of the proposed structure of the sine-cosine generator. In addition, such structure can operate with higher circuit frequency as compared with the two others.
Keywords: Digital Sine-Cosine Generators, Second Order Structure, CORDIC, FPGA Implementation

Thinking performance comparison of the designer in architectural education between the use of digital and traditional method

Dr. N.T. Alkymakchy

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 20-34
DOI: 10.33899/rengj.2012.47233

It is obvious to argue that the current era is a computer age which dominate scientific and academic fields, and thus have formed a new language used in most of life disciplines. Since the architecture is the reflected mirror of the culture, social and technological development over the centuries, it has become a fertile ground in which various disciplines interact from the generation of the idea, till building construction.
Many schools of architecture try to catch up with this trendby inclusion of computer studies into their educational curriculum to fit what is required from students in the exercise of the profession, without looking deeply at what can affect the design thinking productivity.
This paper presents an evaluation studyof the architecturaldesign education by applying a performance comparison between students using the sketching as a design toolduring conceptual phase of design vs. students using digital means to accomplish the design mission, in order to detect the impact of digital medium on the degree of productivity of design thoughts during that phase and its returns positively or negatively on the overall productive thinking during the design process.
Key words: architectural design, architectural education, digital medium, productive thinking

Implementation of Encoding Circuit for Inverse Differential Manchester Code (IDMC) And Clock Recovery Circuit

Warqaa Youns Ibraheem

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 27-37
DOI: 10.33899/rengj.2012.47151

Abstract
In this research an inverse differential Manchester code (IDMC) circuit is implemented to encode random data using logical circuits, and clock recovery circuit is implemented too. A design of the first stage of clock recovery circuit which represents an edge detector circuit has been implemented using two one-shot mono-stable )74121( to detect the rising and falling edges respectively.
The two circuits are tested practically at a low bit rate (1Kb/s) to study there operations. The encoding and clock recovery processes observed using oscilloscope. A comparison is made using simulation program (MATLAB 7.4 ) with the practical results and they were close to simulation results. The encoded circuit has been tested at (5Mb/s) which is lying in Token ring LAN range.
In this research a practical illustration of the effectiveness of high pass filtering on random data has been made and compared with IDMC encoded data, this comparison improve the advantages of line code that have dc balance and high transition density which are lack in the random data.

Keywords: Line Code, Inverse Differential Manchester encoder circuit, clock recovery, practical implementation

Metaphoric Image in Contemporary Iraqi Architecture

Dr. Ali haider Saad Al-Jameel; Mazin Jaber omar Al-Nima

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 35-57
DOI: 10.33899/rengj.2012.47237

Abstract
Metaphor is considered as one of the concepts that were adopted by Post_Modern Architecture in the context of the suggestions for solving the problems of Modern Architecture concerning form, meaning and intercommunication. As the direct result of the metaphoric process is the (Metaphoric Image), this research aims to define the specialties of Metaphoric Images in Contemporary Iraqi Architecture within the period from 1950 until now. In fact, the research presents a new approach to classify Iraqi Architectural Trends according to the concept of Metaphoric Image.
In the application section, (23) metaphoric images were selected from the contemporary Iraqi Architecture and studied by a questionnaire regarding different aspects of the concept of Metaphoric Image. The data collected was statistically treated, and according to the results, the images were analyzed and classified, to get finally, the conclusions, which clarify their specialties. Final discussion confirmed the possibility of the approach metaphoric images in clarifying and defining the differences between different Iraqi Architectural trends.

Matlab SimulationDesign and performance Comparison of OFDM &FH-OFDM Systems

Ammar Abdul-HamedKhader

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 38-48
DOI: 10.33899/rengj.2012.47154

Abstract
Single-carrier techniques are vulnerable for fading and multipath propagation. Recently, multicarrier modulation (MCM) or OFDM have received considerable attentions andhave made a great deal of progress in world. Also spread spectrum techniques are robust against fading and interference. In this paper a non-coherent FH-OFDM system is proposed to improve the performance of OFDM system in multiuser interference. This system is examined using two differentschemes of hopping pattern, namely, Random FH (RA-FH) &Revolver FH (RE-FH).The comparison indicates that RA-FH is more efficient than RE-FH and conventional OFDM for multiuser interference.When compared with previous works that depend on Cluster hopping (CH) Diversity System (DS), the proposed system possesses BER of less than (0.001)for six interferes with high SNR.

Keywords: Orthogonal Frequency Division Multiplexing (OFDM), Frequency Hopping OFDM (FH-OFDM), Random FH (RA-FH) and Revolver FH (RE-FH).

Effect of Partial Heating on Natural Convective Heat Transfer in an Inclined Porous Cavity

Muyassar E. Ismaeel; Dr. Amir S. Dawood

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 49-60
DOI: 10.33899/rengj.2012.47156

Abstract
This paper reports a numerical study of natural convection heat transfer in an inclined square porous enclosure partially heated from bottom. The finite difference technique with Gauss – Siedel method is used to solve the governing equations. The governing parameters are modified Rayleigh number, inclination angle, and insulation ratio (Length of insulated part / Total length of the cavity). It is seen that the governing parameters have pronouns effect on the rate of heat transfer. However, the increases in inclination angle increase the rate of heat transfer until it becomes maximum then decrease to unity at the angle 180˚. Also, the increase of insulation ratio decreases the rate of heat transfer and the angle of maximum heat transfer.

Keywords : Natural Convection , Porous , Partial Heating , Inclined

Voltage and Frequency Regulation of a Three Phase Induction Generator Using Voltage Source Inverter

Prof. Basil M. Saied; Mr. Hasan A.Mohammed

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 58-69
DOI: 10.33899/rengj.2012.47240

ABSTARCT
In this paper the study of a three phase SEIG system under steady state condition is presented. In order to obtain self excitation, a voltage source inverter (VSI) supported by a battery energy storage system and based on sinusoidal pulse width modulation (SPWM) strategy is used. The output generated voltage and frequency are adjusted by changing modulation index (M). The relationship between the modulation index (M) and (dc) battery voltage source has also been found in order to regulate the value of terminal voltage. This system has been also examined with the existence of capacitor located at the D.C link side of the inverter, electronic load has been used to absorb the excess power and also to limit the DC voltage across the capacitor from exceeding the limit , while the generated terminal voltage is fixed by adjusting the modulation index.
As a result the terminal voltage and frequency fluctuation due to load and speed changes are eliminated. The generated voltage waveform is sinusoidal with (THD) less than (4%), keeping power quality within the international standards. both simulation and experimental results are in agreement with objectives of this research

Numerical Study of Heat Transfer by Natural Convection of Porous Layer Using Non-Equilibrium Model

Mohanad K. Radhi; Amir S. Dawood

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 61-75
DOI: 10.33899/rengj.2012.47157

Abstract
This numerical study documents the phenomena of heat transfer by natural convection in thermally non-equilibrium porous cavity for Darcy flow model. The cavity is heated from below at constant temperature with keeping the upper plate isothermal . The side walls were assumed to be thermally insulated. Finite difference method has been employed for discretization of governing equations which include a Darcian momentum equation and energy equations for solid and fluid phases. An iterative Guass-Seidle method was applied for determination of final solution of governing equations. This investigation was performed under the effect of the following non-dimensional groups: modified Rayleigh number , scaled heat transfer coefficient and thermal conductivity ratio . The non-equilibrium is found to be affected by scaled heat transfer coefficient more than being affected by the thermal conductivity ratio. So It had been noticed that all Nusselt numbers are affected by the thermal conductivity ratio, while the effect of scaled heat transfer coefficient was confined to a solid phase Nusselt number.

Keywords: Porous Layer, Heated from Below, Thermal Non-equilibrium Model

Aerobic Composting of Municipal Solid waste in Mosul City

Soad A. Abawi; Nadia A. Yakoob; Hamid A. Hamid

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 70-83
DOI: 10.33899/rengj.2012.47250

Abstract
An aerobic digestion for solid waste samples which had been mixed randomly to represent the normal (real) case, and for samples prepared to have Carbon to Nitrogen C:N equal (1-30) as an ideal case. The result of this process was a dry matter has 1:3 the original weight of the used solid waste in the digestion and this product was called compost. The duration of digestion for ideal case was (23) days in summer and (27) days in winter, while for normal case it was (30,33) in summer and winter respectively. In this research several factors effecting on the digestion such as (temperature of air and mix, pH variation ,water content and volume reducing of solid mixture were studied). we concluded that the effect of air temperature variation was mild on digestion, and the water content was in the ideal range of the process,. The solid waste volume decreased in the end of digestion process for ideal case to (37,40.5)%, while decreased to (39,41)% for real case in the summer and winter respectively. The produced compost in both case was shown free from pathogenic microorganism and rich in nutrients (N, P, K) and their concentrations approach to commercial compost as well as their economic value. It has been found that the heavy metals concentrations in the resultant compost were in the standard limits.

Experimental Study of Lift/Drag Ratio Enhancement Using Continuous Normal Suction

Taha A. Abdullah; Dr. Laith M. Jasim; Dr. Amir S. Dawood

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 76-84
DOI: 10.33899/rengj.2012.47159

Abstract
An experimental work of continuous normal suction from the wing upper surface effects on the aerodynamic forces is carried out, as well as, the effect of normal suction slot channels location and the mass flow rate sucked strength are involved in this study. The wing model with NACA-0015 has been made to achieve normal suction from the wing upper surface by means of four slot channels. The satisfaction of the suction is done by using vacuum pump. The tests are to be done for incompressible flow over wing with and without a continuous normal suction for three different angle of attack 8, 12 and 16 Deg., and for three different Reynolds numbers 13.6×104, 20.4×104 and 24.5×104. The results showed that the continuous normal suction can significantly increase the lift to drag force ratio, and this ratio is increasing more as the strength of the suction increases.

Keywords : Aerodynamic – Incompressible Flow – Boundary Layer Control – Normal Suction– Experimental work – Lift and Drag Coefficient

Experimental Study for Improving the performance of Stepped Spillway using an Obstructions

Elham Majeed Kurukji

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 83-93
DOI: 10.33899/rengj.2012.47255

Abstract

In this paper the energy dissipation was studied using stepped spillway, in addition to that the elimination of air pockets which take place at steps was also studied by using obstructions along the edge of steps. These obstructions were made from iron with square cross-section. Several experiments were conducted on stepped spillway with and without obstructions. The results of the experiments showed that these obstructions were very successful in eliminating air pockets. Their present in general had a positive effect on energy dissipation along the stepped spillway. The results also indicated that the use of these obstructions should be started from second step until the middle step of the spillway.
Keywords: stepped spillway, obstructions, energy dissipater, open channels, discharges.

On The Durability of fine Grained Soils Stabilized With Lime

Dr. Suhail Adrees A. Khattab; Yousif Abduallah Hussein

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 85-92
DOI: 10.33899/rengj.2012.47161

Abstract
Measuring the durability of lime stabilized soils is one of the main concerns in soil stabilization, since there is no standard procedure for this case. This research studies the durability of lime stabilized fine grained soils using the slake durability device.
The effects of curing time and temperature, molding moisture contents, test duration time, and the effect of drying or wetting the samples before slaking, on the durability of gypseous soil (34% gypsum) A and clayey soil B were studied. The results showed that the increase of molding moisture content decrease the weight loss for both soils, also it is found that soil A gave higher weight loss than soil B. Increasing the curing temperature or curing time decreases the loss weight due to pozzolanic reaction.
On the other hand, results indicated that the specimens wetted before slaking gave higher weight loss than specimens dried before slaking.
Finally, a linear relationship was obtained between test duration time and weight loss of soils. It is found that curing for 2 days at 25°C is approximately equivalent to curing for (4-13.5) days and (3.4-13.5) days at 25ºC for soil A and B respectively.
Key words: durability, lime stabilization, slake durability, gypseous soils.

Numerical Modeling of Pore Water Pressure Development within a Thin Clay Core in an Earth Dam

Amina. A. Khalil

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 93-109
DOI: 10.33899/rengj.2012.47163

Abstract
This work aims at studying the pore water pressure development within a thin clay core in an earth dam. The study consists of two parts; a parametric study for general thin clay core (with and without chimney drains), followed by a case study of BADUSH dam. Different operation levels and storage times with the possibility for rapid rise in water level are considered for the case study. Finally the effect of an earthquake on pore water pressure in this types of a dam was also studied as a case study.
Two dimensional finite element analysis was used to simulate pore water pressure development by GEO-SLOP software taking into consideration saturated /unsaturated conditions. Results showed that the presence of a chimney drain plays an effective role in dissipation of the pore water pressure. In the case of BADUSH dam, a high pore water pressure development was observed, in 8 days as a consequence of a rapid rise of water level, and it must be taken into account when designing dams. Also results show that the pore water pressure in the range of (175-145 kPa) through the typical section and approximately between (25-50 kPa) for the two other sections at the end of construction time, making the height and construction time of the dam are the most effective factors affecting pore water pressure development.

Keywords: Pore water pressure, Finite element, Unsaturated soil, BADUSH dam

Capacity Enhancement InWCDMA Cellular Network

Dr. S.Abdul MawjoudA; T.Hussien

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 110-122
DOI: 10.33899/rengj.2012.47164

Abstract
The third generation (3G) cellular system offers high data rate services compared with 1G and 2G systems, for good services and increased number of users,therefore for an operator,it is most important to utilize all possible resources to improve the network capacity and quality of service (QOS). The aim of this paper is to investigate usingsimulation, the impact ofsectorisation, antenna beam width and antenna tilting on capacity. The area of study is a cellular network in urban area with 13*13 Km containing 19 sites, four different sectors used are 1sector,3sectors,4sectors and 6sectors, five different antennas are used in the simulations with 3dB beam width of 120o,90o,65o and 33o and also an Omni-directional antenna, two types of tilting considered are mechanicaland electrical tilt, the result obtained show that the capacity depends on many parameters (load, interference, service type, sectors number, antenna tilt) and can be increased in the proper choice of theseparameters.
Keywords: Cellular system, Cellsectorisation,Antenna tilt, Capacity.

Comparison of Four Neural Network Learning Methods Based on Genetic Algorithm for Non-linear Dynamic Systems Identification

Dr. Rafid Ahmed Khalil

AL-Rafdain Engineering Journal (AREJ), Volume 20, Issue 1, Pages 122-132
DOI: 10.33899/rengj.2012.47165

Abstract
Non-linear dynamical systems are difficult to control due to the model uncertainties and external disturbances that may occur in these systems. This paper addresses the problem of identification using dynamic neural networks (DNNs) based on genetic algorithm (GA) for nonlinear dynamic systems. Four different dynamic neural networks are used for identification of the same nonlinear dynamic system, using the genetic algorithm (GA) to train the Layer-Recurrent Network (LRN), Focused Time-Delay Neural Network (FTDNN), the Elman Network, and Nonlinear Autoregressive Network with Exogenous inputs (NARX). The simulation results show the generalization ability of the four dynamic neural networks which provide the high precision of model of the nonlinear dynamic system. Also this paper illustrates the advantages and disadvantages of the different dynamic neural networks trained by GA.
Keywords: Dynamic Neural Networks, Nonlinear system identification, genetic algorithm.