Articles

DYNAMIC EQUILIBRIUM FOR DETERMINING DRAIN SPACING FOR DIFFERENT SOILS
Dr.Abdul-Sattar Aldabagh, Entesar M.Ghazal (Author)
June 2005 ,Pages 1-11

Abstract: ABSTRACT The main purpose of drainage is to provide a root environment that is suitable for the maximum growth of plants. This study is conducted to find the drain spacing using dynamic equilibrium concept for four different soils with different drain depths, and compare the results with those obtained for the peak irrigation period and the steady state equations using arithmetic, geometric and exponential means. The study included soil texture and hydraulic conductivity tests for four different soils. The drainable porosities of soils were found from especial curves. Two crops were chosen(maize and cotton) and their water requirement and growing season were estimated from previous studies. A computer program was made to obtain the drain spacing using the previously mentioned methods. The drain spacings obtained with the dynamic equilibrium concept were higher than those obtained with the peak irrigation period .The difference in drain spacing becomes more evident with greater depths and higher values of drainable porosity. The drain spacing required for maize is higher than that for cotton. This means that the spacing is affected by both soil type and crop

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EFFECT OF RE-VIBRATION TIME AND STEEL FIBER CONTENT ON THE PROPERTIES OF CRUSHED CEMENT-SAND MORTAR CONCRETE Dr.
Payman Hassan, Ali R. Yousif, Dr. Omar Qarani Aziz (Author)
June 2005 ,Pages 1-12

Abstract: Abstract The investigation aims to study the effect of re-vibration time and amount of steel fiber on the properties of concrete made with crushed cement-sand mortar as coarse aggregate. Three mixes were prepared with 0.00, 50 and 100 percent replacement of natural gravel by crushed cement-sand mortar aggregates. Mix proportions of concrete were 1: 2: 3 by weight. The water cement ratio of 0.50 to 0.60 was used to obtain the same workability for all mixes throughout the research. The specimens were cast to investigate compressive and splitting tensile strength of concrete. The results showed that concrete made of crushed cement-sand mortar as coarse aggregate had lower workability than concrete made with natural gravel aggregate for the same water cement ratio. This reduction in workability is reduced for the richer mixes and the influence of coarse aggregate on the workability decreases with an increase in the amount of cement in the mixture. Concrete compressive and splitting tensile strength were improved due to re-vibration by about 19 percent at the peak value (about one hour after initial vibration) with volume fraction of steel fiber of about 0.5 percent. The steel fibers improve the compressive strength of concrete by about 8-11 percent and the splitting tensile strength by about 10.3 percent for the same period of revibration.

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EVALUATION OF THE GROUND WATER IN MOSUL CITY
Huda H. Badr, Khalid M. Khidir, Hameed .R. Rafike (Author)
June 2005 ,Pages 12-28

Abstract: ABSTRACT In this research an evaluation of the ground water quality at the area located on both sides of Tigris river in Mosul city. Where thirty wells were had been chosen and water samples were taken monthly for chemical and physical tests (pH، temperature، Ec، COD & BOD)، from each well for period from October 2001 to May 2002. Coliform bacteria test were done for all wells during November and February. The computer program Surfer 32 is used for preparing a topographic map and contour maps depending on the data obtained. For the evaluation of ground water quality a computer program in( Visual BASIC) were made to analyze the collected data. The result of this research shows that the ground water are polluted with coliform bacteria, it means that the ground water polluted by recharging sewage water.There is a high concentrations of salts and organic material in the ground water.Also the results of the analysis showed that the quality of the ground water were improved during the period of the raining season

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Effect of Stress – Strain Relationship on the Elasticity Modulus and Moment Capacity
Dr. Mereen Hassan Fahmi (Author)
June 2005 ,Pages 13-32

Abstract: Abstract: The Effect of strain on the elasticity modulus and moment capacity of members are studied using different types of stress – strain relationships (linear, elasto-plastic, elastic perfectly plastic, bi-linear, tri-linear and other continuous models) for bending with or without axial loads using the steps of solution shown in the research. Generally in all cases inelastic modulus reduced with increasing the strain and stress level and significant decrease is occurred in the value of inelastic modulus, the value of inelastic modulus reduces to about (50%) of its initial value when the stress value within (0.4-0.5) of the yield strength. Effect of stress ratio (RF) and strain ratio (Rε) are also studied. Suitable equations are proposed to estimate the values of inelastic modulus and moment capacity

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Preliminary Investigation of the Economics of the Stratified Integrated Collector – Storage Domestic Hot Water System in Iraq
Maan S. Al dabbagh, Dr. Ghalib Y. kahwaji (Author)
June 2005 ,Pages 29-38

Abstract: Abstract: This research aims at investigating the economics of domestic solar hot water systems in order to promote the use of such systems in Iraq in spite of the low prices of the natural energy sources. The integrated collector storage system, suggested by Kahwaji, is adopted in this study due to its simplicity and good thermal performance especially with respect to nighttime heat loss. Thermal and economics analysis indicated that the system can provide savings of 49 %, 56 %, 35 % and 58 % in the domestic hot water energy expenditure in the environment of the cities of Mosul, Baghdad, Basrah and Ratba respectively when 20 % inflation rate for the price of electricity and a system life time of 20 years are used.

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Khabur River Flow Modeling using Artificial Neural Networks
Jowhar R. Muhamad, Jwan N. Hassan (Author)
June 2005 ,Pages 33-42

Abstract: Abstract: Modeling a hydrologic time series has been one of the most complicated tasks owing to the wide range of data, the uncertainties in the parameters influencing the time series and also due to the non availability of adequate data. Recently, Artificial Neural Networks (ANNs) have become quite popular in time series forecasting in various fields. This paper demonstrates the use of ANNs to forecast Khabur monthly river flows for flow data from January 1958 to December 1975. Using the feed forward network. The network is trained using the lagged or delayed variables from SARIMA model as an input variables for the network. ANN model for mouthy flow gives better result in comparison with Traditional ANN models and SARIMA model.

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Simulation of Adaptive Blind Multiuser Detector in DS-CDMA Wireless Communication
R. Hussein, Dr.S. Mawjoud (Author)
June 2005 ,Pages 43-55

Abstract: Abstract: Multiuser detection is the demodulation of signals of different users interfering with each other. This phenomena known as multiple access interference occurs mostly in code division multiple access (CDMA) systems. In this paper the study and analysis of the blind adaptive multiuser detection algorithm is achieved for directsequence code division multiple access (DS-CDMA) communication systems. The goal is to obtain multiuser detectors that require only knowledge of the signature waveform and timing of the desired user. Comparison is performed of the blind adaptive technique with the conventional detector (matched filter detector) or (M.F.D) in perfect power control and in the presence of the near-far effect. In the present simulation, the blind adaptive multiuser detection showed an excellent bit error rate as compared to the conventional detection with the same requirements. Also the blind detector showed an immunity towards the near-far problem. In this simulation the use of adaptive variable step size is used in contrast to the constant step size shows improvement in speed convergence and stability of the algorithm adapte

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Ultrasonic Defect Sizing in Grey Cast Iron Compared with Steel, Using the Maximum Echo Amplitude Technique
Dr. S. I. Ibrahim (Author)
June 2005 ,Pages 56-71

Abstract: Abstract: In ultrasonic defect sizing using the maximum echo amplitude technique, the reflected echo signal height is taken to be related to the amount of ultrasound propagated energy which is reflected from defects and to the information contained in this reflected energy. In this investigation horizontal drilled holes of known sizes are considered in grey cast iron which is usually treated as the most difficult type of cast irons when ultrasonically inspected, due to its high sound attenuated nature. The defects sizing results obtained from grey cast iron are compared with those obtained from a steel of a similar pearlitic matrix structure as a reference material. 2, 4, 6 & 8 mm drilled holes at known depths are prepared in both grey cast iron and steel test samples. Maximum echo amplitude sizing method is adopted, using both compression wave probes & shear wave probes of 1,2,4 & 6 MHz frequencies at different scanning positions. Although the results are only limited to defect sizing in grey cast iron with reference to steel, they do

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