Print ISSN: 1813-0526

Online ISSN: 2220-1270

Volume 16, Issue 5

Volume 16, Issue 5, Summer and Autumn 2008, Page 1-101


Multi Rate Audio Coding Based On Combining Wavelet with DCT Transform

Adnan I. Hussein

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 1-8
DOI: 10.33899/rengj.2008.44849

Abstract
In this paper an efficient algorithm proposed to encode the audio signals with multirate capability. The algorithm based on combining discrete wavelet with DCT transform for maximum decorrelation. The coefficients of the frame are scaled and encoded using non uniform quantizer. The main features of this algorithm are: low complexity and near transparent audio quality resulted in the range 48 – 64 Kbps for most SQAM signals. The algorithm outperform much better than DWPT with SPIHT algorithm previously.

Keyword : wavelet , DCT , audio , coding , Huffman , and psychoacoustics.

Effect of Induction Motors Parameters On the Performance at Transient Operating States

Abdul Ghani A. Abdul Ghafoor

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 1-11
DOI: 10.33899/rengj.2008.44872

The effect of induction motors as loads in modern electrical power systems is very large, specially when these motors suffer from transient behavior conditions. These transient conditions, which occur owing to electric faults characterized in turn by their high speeds, have their huge impact on the entire transient conditions occurring in electrical power systems. Park-Gorve equations technique is used in this research study in order to obtain the induction motor equations which are frequency variation dependent, and would thus result in getting the motor parameters under the transient operating conditions.
This research study shows that maximum torque tends to increase motor current and decreasing the motor reactance. It shows that short circuit currents increase with the increase of mechanical loads of the motor.
It also shows that lower moment of inertia result in larger starting motor currents and larger growth of motor current.

Keywords: Induction Motors, Parameters, Transient.

A New Technique Of Microcomputer Based Overcurrent Relay

Mohammed Yahya Suliman

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 9-19
DOI: 10.33899/rengj.2008.44851

Abstract

A new technique of three phase overcurrent relay is described in this paper. The performance of the new design shows the ability to obtain any shape of characteristic using exponential type model with high accuracy. Also the new design used more accuracy, fast measurement for peak detection with error less than 2%. The relay tested for normal and very inverse characteristics, also tested for line-to-line fault the results show the ability of discrimination the fault current and isolate the section of the system affected by a fault so that the remaining system can continue to operate normally.

Key-words: overcurrent relay, Peak detector, time coordination margin (TC), time multiplier setting (TMS), Programmable Peripheral Interface 8255 (PPI).

The Earth Thermal Machin And The Green House Effect Bassam M. Mustafa

Bassam M. Mustafa

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 12-19
DOI: 10.33899/rengj.2008.44877

In this research we try to explain the greenhouse effect by suggesting a model looking to the earth –atmosphere system as a thermal machine .In this model earth absorbed heat and light energy from the sun ,doing work in achieving biological and other activities . the access energy is transmitted to the space. This system really represent a reversible thermal machine obey the 2nd law of thermodynamics and with efficiency about 56% . But the increase in the burning materials lead to an increase in the percentage of CO2 ,and since its molecules can absorb the radiation from the earth . thus leads to form irreversible engine with entropy production , by calculating the increase in CO2 the increase in entropy production is calculated . The increase in entropy increase earth’s temperature and lead to the greenhouse effect .

Key Words : Green house , Global otel for Green house, Atouspheric changes.

Advance of wetting pattern during redistribution phase under trickle source

Haqqi I. Yasin

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 20-26
DOI: 10.33899/rengj.2008.44882

Abstract

The soil wetting pattern under a trickle source is developed from water movement in wetting phase and redistribution phase. The present study included developing equations for vertical advance and horizontal advance of the wetting front during the redistribution phase. The advance is a function of time from the beginning of water application, total application time, water application rate, and saturated hydraulic conductivity. The same of equations can be used during the wetting phase too. The data of water movement in the soil under trickle source were obtained from previously developed researches.

Key words : trickle source, wetting pattern, wetting phase, redistribution phase.

Adaptive Filter Application in Echo Cancellation System and Implementation using FPGA

Rafid Ahmed Khalil

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 20-32
DOI: 10.33899/rengj.2008.44853

Abstract

In telephony system, the received signal by the loudspeaker, is reverberated through the environment and picked up by the microphone. It is called an echo signal. Which is in the form of time delayed and attenuated image of original speech signal, and causes a reduction in the quality of the communication. Adaptive filters are a class of filters that iteratively alter their parameters in order to minimize a difference between a desired output and their output. In the case of acoustic echo, the optimal output is an echoed signal that accurately emulates the unwanted echo signal. This is then used to negate the echo in the return signal. The better the adaptive filter simulates this echo, the more successful the cancellation will be. This paper examines LMS algorithm of adaptive filtering and the application in acoustic echo cancellation system. Employing a discrete signal processing in Matlab for simulation with real acoustic signals. Also a hardware implementation of an adaptive filter have been developed using XC3S500E Xilinx FPGA chip, and VHDL language on RTL abstraction level.

Keywords: Acoustic echo cancellation, Adaptive Filter, FPGA, VHDL.

The Daily Optimal Management Of Dokan Reservoir At Minimum Levels Of Discharges For Maximaze The Hydroelectric Power

Oday .Y. Thanoon; Abdul-Wahab.M.Younis

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 27-32
DOI: 10.33899/rengj.2008.44895

Abstract
Aim of the present research is to find the best optimal daily management and operation policy of Dokan dam reservoir using Discrete Differential Dynamic Programming(DDDP) at minimum levels of inflow discharge during the period of 30 years for maximizing the hydropower generation (1965-1995). The results of this study were compared with previous results for an optimal monthly management and operation policy for the same reservoir and the same year. .
It has been found that the total annual hydroelectric generation power for the case under investigation is 1073 MW, ie, an increase of 93 MW from the monthly operation of 980 MW.
Also,it has been found that the number of trials to reach the optimal management ranged between 70and 90 trials in the daily operation, while the optimal management was observed in the case of monthly operation at were trialsfrom35to70. All results obtained for the daily optimal operation policy were good without neglecting any restrictions demanded taken in to consideration.

Key words: water resources, optimal management, hydroelectric power

Tele-operated Vehicles System Using WLAN and Industrial Ethernet Techniques

Qutaiba I. Ali

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 33-42
DOI: 10.33899/rengj.2008.44856

Abstract

Tele-operated vehicles have been used in different applications and environments. This paper studies the case in which a Tele-operated vehicle is guided through city streets. OPNET package is used to simulate the behavior of the system. Industrial Ethernet is assumed to be the field bus network of the vehicle and WLAN technique (IEEE802.11b) is assumed to be the communication link between the vehicle and the control center. The real time performance of the system is investigated during changing some important parameters. Then , image compressing technique is used to enhance the real time behavior of the system.

Keywords: Tele-operated Vehicle, Industrial Ethernet , WLAN , Image Compression

Plot in Architecture The representation of a single point In time

Janan Abd Satar Mustafa

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 33-50
DOI: 10.33899/rengj.2008.44897

The architectural literatures dealt with plot as a tool to create the architectural text , using it as a mean of giving order , selecting , sequencing or developing images in the design process as it is connected with the intertextual texts or texts that telling stories and representing events.
It is a plan to create an architectural product and to map out the structure of design process and the harmonically consequences of its steps.
It works in two levels : the conceptual structure and the formal one.
The research dealt with a temporal sequence of events and the representation of time in spatial form , it focused on the single point in time or “ frozen moment “ common to realism , photography, or even the ordinary genre scenic frames one episode while implying what went before and what will follow.The study results comes up with new characteristics and values for the single point in time and the conclusions showed that this strategy contains in some of its parts the strategy of linear consequences that links a series of individual episodes into linear sequences and it determined the specific differences between them.

Key word : plot, temporal patterns of events, sequence of events, structure of events, architectural Narrative.

Forced Vibration Analysis Of Rectagular Plates Usinig Higher Order Finite Layer Method

J. H. Haido; A. A. Abdul-Razzak

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 43-56
DOI: 10.33899/rengj.2008.44859

Abstract

In this paper a higher order finite layer formulation based on the auxiliary nodal surface (ANS) technique for a forced vibration analysis of rectangular plates is presented. The forced vibration analysis has been performed using the Newmark integration method for investigating the vibration characteristics and finding the response of rectangular plates under the action of dynamic loads. The forced vibration of the rectangular plates subjected to moving and impact loads has been studied.
Several examples have been studied to show the good performance of the higher order finite layer with one ANS for forced vibration analysis of plate.

Keywords: Finite layer, Forced Vibration, Thick Plate.

The Relation of Space Containment of Traditional Alleys with its Integration Degree (An Analytical Study of the District of Jame Al-Kabeer in the Old City of Mosul)

Hatim Hazim Al-Sofi

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 51-62
DOI: 10.33899/rengj.2008.44900

Abstract
The Arabic–Islamic cities is characterized with its narrow alleys and their hierarchy in width and containment. So the district of Jame Al-Kabeer which represents an example of the urban fabric of the old Arabic–Islamic city of Mosul has been selected to measure the degree of alley's containment enclosure by measuring the percentage of the width (W) of the alley to the height (H) and its integration within the Space Syntax theory. The shape of the integration core was peripherical integration core and the segregation core was in the center of the district. The percentage of the narrow alleys was 60.6% and the normal alleys 3.4% which represent the high degree of enclosure of the alleys in general. The statistical relation between the degree of integration and the degree of containment of the alleys was significant.

Key Words: Urban Design, Urban Space, Arabic – Islamic Cities.

Nonlinear Finite Element Analysis of Fibrous Reinforced Concrete Beam-Column Joints

N. S. Al-Saffar; S. A. Al-Ta

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 57-69
DOI: 10.33899/rengj.2008.44862

In this paper, the finite element method is used to study the nonlinear behaviour of beam-column fibrous reinforced concrete joints under short–term monotonic loading. Concrete is represented by eight nodded isoparametric elements and the reinforcement was represented by axial two noded bar elements embedded in the concrete elements. Strain hardening approach, has been employed to model the compressive behavior of the fibrous concrete. In tension a continuous function is used to model fibrous concrete in the pre-peak and post – peak states. Material nonlinearities due to cracking of concrete, crushing of concrete in compression, debonding and pull – out of fibers and yielding of reinforcement have been taken into account. A smeared fixed crack approach of the cracked concrete in tension is assumed. An incremental – iterative scheme based on Newton – Raphson’s method is employed for the nonlinear solution algorithm and a displacement criterion is adopted for checking the convergence of the solution. Several previously published test results for fiber reinforced concrete beam-column joints were analyzed and the numerical results showed good agreement with the published experimental results.

Keywords: Beam, Column, Fibrous concrete, Finite element, Joint, Nonlinear analysis.

The Effect Of Center Distance Change On Gear Teeth Engagement And Stress Analysis

Omar D.Mohammad

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 70-81
DOI: 10.33899/rengj.2008.44864

Abstract

The present study concentrates on the changes in gear teeth engagement and stress analysis of meshing teeth when gearing system is operated at a non-standard extended center distance. (Ansys) programming using F.E.M have been applied for stress analysis on a gear model. Many cases with changing center distance have been studied. It is clear that the operating center distance was increased; the stresses generated on tooth will be increased dependently.

Keywords : Spur gear, Center distance, Teeth engagement, Stress analysis

Thermal and Economic Evaluation of Using a Single Stage LiBr-H2O Absorption Chiller to Boost the Power Output of a Gas Turbine Generator

A.R.Habbo Mohammed; Ghalib.Y.Kahwaji

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 82-93
DOI: 10.33899/rengj.2008.44867

Abstract

The exhaust gases of gas turbines carry a significant amount of thermal energy that is usually expelled to the atmosphere without taking any further part in the power generation process. This low grade thermal energy can however be put into beneficial use as a heat source to a vapor absorption chiller that serves as cooling system to be operated during hot months to cool inlet air to the gas turbine to raise its power generation design level.
This paper describes the thermal and economic advantages of using a Single Stage LiBr-H2O absorption chiller to boost the power output of a gas turbine generator with application to Mosul gas turbine power plant. The results showed that maximum increase in power output when inlet cooling involved is approximately 17.5%, which occurs in July and August being the hottest month in the year. The economic results showed that maximum economic saving of $34.9 million dollar which represent 8% saving can be obtained at inflation rate of 6% and interest rate of 1%.

Key words : Gasturbine , Absorption system , Thermal analysis , Economic analysis.

Load Sharing On Spur Gear Teeth And Stress Analysis When Contact Ratio Changed

Omar D.Mohammad; Sabah M.J.Ali

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 5, Pages 94-101
DOI: 10.33899/rengj.2008.44869

Abstract


The present research work concentrates on the effect of contact ratio change on the stresses generated on meshing gear teeth. Many cases of contact ratio (1.6, 1.7, 1.8, 1.9 & 2.0) have been studied. In each case the value and location of load were determined on the involute profile of meshing tooth. Also the angular position of this tooth for critical loading condition (at the instant when the generated root stresses at the maximum state). (Ansys) programming using F.E.M have been applied for stress analysis on gear model. From this study it is clear that, the highest contact ratio resulted in the lowest generated tooth stresses (i.e. the highest load carrying capacity). This depends on the value, location and direction of load applied on tooth involute.

Keywords : Spur gear, Contact ratio, Load sharing, Stress analysis