Table of content

Thi-Qar University Journal for Engineering Sciences

مجلة جامعة ذي قار للعلوم الهندسية

ISSN: 20759746
Publisher: Thi-Qar University
Faculty: Engineering
Language: English

This journal is Open Access

About

Thi-Qar University Journal for Engineering Sciences is a refereed scientific journal Established in 2009 accepts articles from inside and outside Iraq in different engineering sciences. These articles should not be submitted for publication in any scientific journal or conference proceedings.

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Contact info

thiqarej@gmail.com

Table of content: 2011 volume:2 issue:3

Article
Performance Improvement of Multilevel Load Power System by Using Two-Stages Fuzzy Controller

Authors: Baqer Turki Atiyah Al-lamey
Pages: 1-18
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Abstract

This paper presents a new approach to improve the performance of power system by enhancing the voltage profile and reducing the real power losses based on two stages fuzzy controller which is used to select the appropriate size and location of capacitor banks required to minimize the power losses and maintain the voltage profile in permissible limits. The first stage of fuzzy controller is used to specify the optimal location of capacitors installation, while the optimal size is specified by the second stage . The proposed method is tested on a 34-bus, 74-transmission lines from Iraqi Northern power system with multilevel of loads. The load levels are represented by 50%, 75%, 100% and 125% of peak load and satisfied results are obtained to show the feasibility and flexibility of the proposed method.


Article
Effect of Uniformity of Deficit Irrigation with Saline Water on Production
تأثير تناسق الارواء بمياه الري المالحة على الانتاج تحت الري الناقص

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Abstract

T he study aimed towards developing a computer model to be used for evaluating the effect of water distribution uniformity of deficit irrigation with saline water on field crop production. The development of the model is based on the concept of water balance in the field. For the application of the model, corn crop (yellow maize) autumn season is selected using ready data on reference evapotranspiration at the selected field site (North Jazirah Project – Nineva). Moreover, published data on field sprinkler water distribution around sprinkler head of stationary system are used. The main assumption upon which the model is based is that, for a given case, irrigation water distribution and salinity are fixed for all irrigations during the season. The results of the study revealed that the deficit in the yield ratio increases with the increase in moisture depletion ration and water salinity, but decreases with the increase in the degree of irrigation uniformity. Furthermore, the effect of salinity on production is greater with deficit irrigation, therefore a balance should be sought between deficit irrigation level and water salinity on production under each case of irrigation nonuniformity. Finally, the study showed that the leaching fraction increases as the degree of irrigation uniformity deteriorates because deep percolation losses increase with the reduction in uniformity.

Keywords


Article
Study of Natural Convection in a Horizontal Square Enclosure with 4-Inner Heated Rods
دراسة نظرية للحمل الحر داخل فجوة افقية مسخنة بأربعة قضبان اسطوانية

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Abstract

Laminar, natural convection heat transfer of air filling horizontal space between isothermal (cold) square enclosure and four isothermal (hot) cylindrical rods has been theoretically studied. Finite element method has been used to solve the conservation of governing equations by using software package (FlexPDE). Parametric study has been conducted for the range of Rayliegh number10 ,Aspect ratio 0.11AR0.28. Results are presented in the form of streamlines, isotherms contours and Nusselt numbers. Results showed that the overall heat transfer increases with increasing of both Ra and AR. The values of mean Nusselt numbers are compared with data reported in Ref.[6] and [15] , and good agreement has been achieved. 3 Ra10 5


Article
Novel Space Time Spreading Scheme

Authors: Ahmed Abdel Hadi Fadhel
Pages: 35-43
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Abstract

In this paper two spreading schemes and their detection methods were proposed and compared. The comparison depends on the performance of each scheme in Rayleigh flat fading channel. Space Time Spreading (STS) codes are used with Layered Space Time Codes (LST), with Vertical Bell Laboratories Space Time codes (V-BLAST) in particular. Also,Direct Sequence Code Division Multiple Access system (DS-CDMA) was used as a multiuser criterion. As a result of this spreading,a simple decoding algorithm was used. The simulation shows that STS-LST-DS-CDMA system with 3TX-3RX (3transmitting antennas3 receiving antennas) using all paths between ransmitter and receiver was better than LSTDS-CDMA system by about 4dB in SNR at BER of 10 -4 . More detailed results are shown in Table 1. Also, the proposed scheme (may be partially) solves the problem of the code reuse.


Article
Evaluation the Efficiency of Installing Stone Columns in Ground Improvement of Al-Nassiriya City Soil
تقييم كفاءة استخدام الاعمدة الحجرية في تحسين تربة مدينة الناصرية

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Abstract

This paper investigates the performance of stone columns in soft soil of Al-Nassiriya city (one of Iraqi cities in the south). A geotechnical study of physical and mechanical properties of the soil has been carried out for a selected areas from Al-Nassiriya city. A finite difference Matlab program has been employed in simulation of installing stone columns in the aforementioned soil. Results of the study illustrate using stone columns reduces the settlement of the soil for different values of the modular ratio and replacement ratio, thus the Wmax maximum settlement ratio changes from 30% to 16% of the modular ratios (E/E)=10 and 50 respectively. The effect of spacing and column width is taken intoconsideration. All results are reasonable and harmonic with most last studies. c-


Article
Modeling of the Dissolved Oxygen Profile in Marsh Water by Numerical Solution of ADE Using Finite Difference Method

Authors: Mohammed Dekheel Selman
Pages: 57-73
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Abstract

To evaluate the environmental impact of pollution, mathematical models play a major role in predicting the pollution level in the regions under consideration. Computer models are becoming increasingly important tools in every environmental management aspects. A general one dimensional water quality model (Advection-diffusion Equation ADE) has been developed the dissolved oxygen in Abu-Zirig marsh water. The general one-dimensional model equation was solved using the numerical solution by finite difference discritization and procedure was prepared by writing a computer program in MATLAB program (version 7.6).


Article
Duplex Inhibition of CO2 Corrosion in Iraqi Oilfield

Authors: Sami I.J. Al-rubaiey
Pages: 74-94
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Abstract

New method for inhibition CO2 corrosion in Iraqi oilfield was used in this work. This new method included using combination of heat treatment of steel and added Aromatic (Tetrahydronaphthalene) compounds as corrosion inhibitor in different concentration (0.05%, 0.1%, 0.2%, 0.5% and 1%). The results referred that the weight loss was reduced as inhibitor concentration increased for all conditions of specimens whether, there were heat treated or not. The combination of annealing heat treatment of samples and using Aromatic compounds inhibitor offered a better corrosion resistance than the combination of quenching + tempering (Q+T) samples. The presence of inhibitor improves the corrosion resistance for annealed samples. For fully annealing, the weight loss was 5 times lesser than that for (Q+T) samples, while the weight loss of steel (as received condition) was 3 times lesser than that for (Q+T)samples.


Article
Study of the Condenser Performance in Al-Nassiriyah Thermal Power Plant

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Abstract

This paper includes a study of the performance of Al-Nassiriyah thermal power plant condenser. Which includes a calculations of the main variables of condenser (heat transfer, condensation rate, overall heat transfer coefficient and vapour pressure) by applying two dimensional mathematical model and depending on the empirical equations of heat transfer. Comparison was made between the theoretical results for Al-Nassiriyah thermal power plant condenser before operation it (standard power plant) with practical data which taken from the plant for the second unit in year 2007. The comparison showed that there was a large difference between theoretical results and the values taken from the plant as a result to the effect of operation conditions.


Article
Study of Mixed Convection Heat Transfer Inside a Vented Square Cavity with Inner Heated Cylinder
دراسة عملية انتقال الحرارة بالحمل المختلط داخل فجوة مربعة الشكل تحوي أسطوانة داخلية مسخنة

Authors: Falah A.Abood --- Sana M. Shrama --- Zainab K. Radhi
Pages: 113-130
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Abstract

The problem of mixed convection heat transfer for laminar air flow in a square cavity with inner heated cylinder is numerically analyzed by finite element method using software package (FlexPDF) to solve the conservation of governing equations. The right vertical wall is kept at constant temperature and the others are adiabatic. An external flow enters the cavity through an opening in the left vertical wall and exits from another opening in the right vertical wall. Results of streamlines, isotherms, average temperature and average Nusselt number of the heated wall are presented for Ri = 0 to 12, 50 .. Re .. 200, Pr = 0.71 and inlet position hi =0.2. From the present analysis it is found that with increases of Re and Ri numbers the convective heat transfer becomes predominant over the conduction heat transfer. The results of streamlines and isotherms are compared with available result of Rahman et al.[8], a good agreement has been achieved.

Table of content: volume:2 issue:3