Print ISSN: 1813-0526

Online ISSN: 2220-1270

Volume 16, Issue 4

Volume 16, Issue 4, Summer and Autumn 2008, Page 1-102


Non-Linear Finite Element Analysis Of Reinforced Concrete Slabs For Creep And Shrinkage

Majid A. AL Jurmaa; Ayad A. Abdul -Razzak

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 1-12
DOI: 10.33899/rengj.2008.44715

A non-linear, layered, finite element model for predicting the time dependent behavior of reinforced concrete slabs under sustained transverse loading is presented. The effects of biaxial creep and shrinkage are accounted for using short form of creep and shrinkage prediction model B3 for structures of medium sensitivity. The layered approach is used to represent the steel reinforcement and discretize the concrete slab through the thickness. The reinforcement steel is represented as a smeared layer of equivalent thickness with uniaxial strength and rigidity properties. Elastic perfect plastic approaches have been employed to model the compressive behavior of the concrete. The yield condition is formulated in terms of the first two-stress invariant. The movement of the subsequent loading surfaces is controlled by the hardening rule, which is extrapolated from the uniaxial stress-strain relationship defined by a parabolic function. concrete crushing is a strain controlled phenomenon. Which is monitored by a fracture surface similar to the yield surface. A smeared fixed crack approach is used to model the behavior of the cracked concrete, coupled with a tensile strength criterion to predict crack initiation. Several examples for which experimental results are available are analyzed, using the proposed model .The comparison showed good agreement.
Key words: Creep and Shrinkage, Nonlinear Analysis Reinforced Concrete Slabs, Time Dependent analysis.

Studying The Influence Of Compacting Method On The Engineering Properties Of Expansive Clayey Soil

Ali H. Al-Bayati; Ibrahim M. Al-Kiki; Khawla A. Al-Juari; Anas F. Qassid

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 1-16
DOI: 10.33899/rengj.2008.44741

Abstract
This study deals with the effect of two methods of compaction (static compaction (S.C.) and dynamic compaction (D.C.)), on the engineering properties of high plasticity clayey soil (CH) selected from Mosul city.
Results showed that maximum dry density of soil compacted by static method is higher than that compacted by dynamic method. But the inverse was obtained for optimum moisture content. Unconfined compressive strength, effective shear strength parameters (ć, ǿ), splitting and California Bearing Ratio (CBR) for soil compacted by dynamic method has higher values than that compacted by static method.
Swelling pressure and free swell tests gave higher values under static compaction method. But the values of compression index and coefficient of consolidation using dynamic compaction method gave higher values.
On the other hand, the results of crumb, slackening and pinhole tests showed that the internal erosion of soil compacted by dynamic method are less than that compacted by static method. From filter paper method and soil water characteristic curves showed that compaction methods had no effect on soil suction. Finally, statistical models between engineering properties for soil compacting by two methods were obtained.

Behaviour And Strength Of High Strength Concrete L-Beams Under Combined Shear, Bending And Torsional Loading

Ferhad R. Karim; Ferhad R. Karim; Omer Qarani Aziz

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 13-29
DOI: 10.33899/rengj.2008.44722

Abstract
This investigation examines experimentally the behavior and ultimate strength of L-shaped reinforced high strength concrete beams under combined shear, bending and torsion.
The experimental program consists of casting and testing (13) high strength concrete beams under bending, shear and torsion. The main parameters are the effect of compressive strength, the eccentricity and transverse to longitudinal reinforcement ratio.
An increase in transverse to longitudinal reinforcement ratio by (21.43%) for beams under 80mm eccentricity of loading causes decrease in ultimate resisting torsional moment by (13.19%), and for an eccentricity of 170mm; the decrease in resisting torsional moment is (15.14%). Increasing in eccentricity for torsion of (112.5%) caused a decrease in load carry capacity by (43.33%) if all types of reinforcement remain the same.
By using multiple nonlinear stepwise regression analysis, based on data in this research and from other literatures; equations are proposed for predicting shear strength at cracking and ultimate loads and torsional capacity at cracking and ultimate loads. These proposed equations showed good agreement when compared with equations given by Codes of practice like (ACI, Canadian and BS) and showed good relations..

Keywords: Bending, high strength concrete, L-shaped beams, shear, torsion.

Effect of chisel plow shanks shape on power Requirements of Tractor

Mahmood Elias Ahmed Al-Taee; Saad Abdul Jabbar Al- Rajaboo

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 17-26
DOI: 10.33899/rengj.2008.44742

Abstract
This study was carried out at two sites of different soil texture, clay and a clay loam during the season of 2005 – 2006 In Mosul .A plough of three different shank shapes have been used . These shapes were vertical, inclined forward and curved with two plough depths of 8-12 cms and 13-17 cms successively with three speeds 3.70, 7.15 and 9.64 km/hour. In order to study the effect of the shank shape on the power requirements -which include the draft force, rate of fuel consumption, slippage ratio and the power loss due to slippage. The two experimental farms have been designed by the use of (RCBD) with three factors and replications. The main results of this study, The vertical shank outperformed at the first site and the inclined forward outperformed at the second site in recording the lowest requirement with their means, the 8-12 cm depth outperformed at the two sites with their means in recording the lowest power requirement, the (3.70) km/ hour speed recorded the lowest power requirement except fuel consumption at the two sites with their means, The second site (clay loam texture) outperformed records the lowest power requirements.and at the effect of interaction between the sites, shank shape, depth and speed on the studied properties the inclined forward shank at depth of (8-12) cm and at speed of (3.70) km/hour gave the lowest power requirement at the second site except fuel consumption.
Keyword: Tillage – Chisel Plow Shanks –– Power requirement

Optimal Multicrop Allocation of Seasonal Water Under Limited Irrigation Water

Anmar Al-Talib; Abdul-Sattar Al-Dabagh; Eman Hazim Sheet

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 27-40
DOI: 10.33899/rengj.2008.44743

Abstract
As water demand is increasing and the world food problem is becoming more pronounced، world efforts are forwarded towards the optimal usage of water resources، specially in regions where water is scare or irrigation is very costly. Inadequate irrigation is considered one of the methods that increase water usage efficiency and the application of optimization methods is essential in order to increase agriculture production.
A mathematical model was developed for optimal allocation of irrigation water under full and inadequate irrigation. The model determines the optimal seasonal allocation of irrigation water between crops. The output of the model are the area and water allocated for each crop under limited and full irrigation، the effects of various management options، as changing the plan of agriculture، type of production function، and value of irrigation water، were studied. The model was run for many percentages of full irrigation ranging from 10% to 100%. The model is considered a good approach for deciding on area and amount of irrigation water which achieves optimal values in irrigation planning projects under limited water resources.
Keywords: irrigation optimization, nonlinear programming, limited irrigation water, water allocation for different crops.

Effects Of Camber Of Beam On Behavior Of Single Span Portal Frames

Kanaan Sliwo Youkhanna Athuraia

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 30-37
DOI: 10.33899/rengj.2008.44725

An attempt is made to study the effect of camber on the behavior (deflection and failure load) of single span portal frames under concentrated load. Two types of cambering were used, the first by cambering both top and bottom surfaces of the beam and the second by cambering the bottom surface only (the top surface is kept leveled) which is more acceptable from point of view of uniformity of super imposed dead load distribution.
There is a considerable effectiveness of the camber on the failure load compared with straight beams (without camber). Also, there is effectiveness considering )dead+live( load deflections for cambered beams compared with straight beams.
Keyword : Membrane Action, Camber, Concentrated Load, Deflection, Failure.

The Use Of Liquid Asphalt To Improve Gypseous Soils

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 38-48
DOI: 10.33899/rengj.2008.44727

This work aimed to study the effectiveness of liquid asphalt in the enhancement of gypseous soils properties. This enhancement is by reducing the effect of water on gypsum particles and increasing strength parameters.
The work included two types of treatments firstly is by mixing technique and the second type is by grouting technique.
The testing program included the determination of unconfined compressive strength, shear strength and collapsibility parameters of untreated and treated gypseous soil with different percent of liquid asphalt.
The test results showed that the maximum unconfined compressive strength and the shear strength of soil increased to an optimum value and then decreased with increasing liquid asphalt.
The study concluded that the mixing technique was better than the injection technique because the mixing technique will cover the particles with a film of asphalt while the injection fills the voids of soil with asphalt. Moreover the results show that the oblique injection gives more strength to the soil than normal injection.
Keywords: Gypseous soil, Liquid asphalt, Soil improvement, Grouting, Injection

Study for the Quality of the Ground Water in Meshraq -1

Gada Younis Abdullah AL-Ubaidy

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 41-52
DOI: 10.33899/rengj.2008.44744

The study of chemical, physical characteristic of the ground water is important to determine the suitability of this water for drinking or irrigation and agriculture uses. The study of ground water in Meshraq-1 is so is important for this area from economic power live. Eight wells had been chosen for this study. Results of these tests show that the ground water in Meshraq-1 law quality, due to industrial hot water pumping may cause this deterioration of water especially SO4-2 will reach (177-1771) p.p.m for the first test and (169-1570) p.p.m for the second test, CO3-2 and HCO3- so this ground water will deteriorate the river.
Key words: ground water – meshraq – quality of ground water – pollution of water.

Complexity Reduction and Performance Improvement of Multistage Detector with Parallel Interference Cancellation for DS-CDMA System

Sedki. B. T. Younis; Bayez K. Al-Sulaifanie

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 49-58
DOI: 10.33899/rengj.2008.44730

Abstract
In this paper we propose a new method which combines the partial cancellation and differencing technique to achieve performance improvement and reduction in complexity, the proposed technique is named Multistage (DP-PIC) Detector. The simulation model for the proposed DP-PIC is implemented in floating and fixed point arithmetic. The simulation results illustrates that a partial cancellation factor of 0.7 and 0.8 in the first and second stage respectively gives a good performance for the proposed technique. A precision of 16-bit is enough to achieve a small performance degradation compared to floating point results. Finally the proposed fixed point DP-PIC is implemented on TMS320C6400 DSP simulator. The implementation results illustrate that 35% complexity reduction can be achieved compared with conventional PIC detection.
Keywords: DS-CDMA, PIC, Complexity reduction, performance improvement.

Dual Irrigation Technology (DIT) Under Surface Irrigation System

Abbod M. Aljumaily; Isam M. Alhadithy

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 53-60
DOI: 10.33899/rengj.2008.44745

In the dual irrigation technology (DIT), irrigation process is divided into two stages. In the first stage saline water is added as a part of irrigation water requirements , then good quality irrigation water is supplied in the second stage to complete irrigation water requirements. Piston flow may accurse in the soil because the time interval between two stages as short as possible , so the water content is greater than field capacity . Piston flow leaches the saline water that used in the firs stage of (DIT) under the root zone depth, so it is minimize the salinity effects of that water. Drainage water of 6 ds/m and Euphrates river water (1ds/m) are used to irrigate corn under furrow irrigation system with (DIT) at Ramady city in Iraq. Advance face in the furrow completes from drainage water , then second stage of (DIT) using river water . The experiment results summarized in the high relative yield (more than 95%) and saving about third quantity of fresh irrigation water. No significant differences in the salinity effects at the upper two thirds of the root zone depth compared with some furrows irrigated by river water only . Salinity effects at the lower third decrease as the distance from the upstream of the furrow increase, logarithmic relation between salinity effect and furrow length is proposed
Key words: Dual Irrigation , saline irrigation water , water quality

Estimation of Design Parameters for Cellular WCDMA Network

S. A. Mawjoud

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 59-68
DOI: 10.33899/rengj.2008.44732

Abstract

The estimation of design parameters for WCDMA network which support different data rate (Multimedia) services is an essential step in network planning. The estimated parameters includes: Cell coverage range using path loss propagation model, average and maximum path loss, throughput, capacity / km2, number of users per cells blocking capacity, tracking efficiency. The parameters are computed for different data rates.

Key words: WCDMA, noise rise, load factors.

Nasma Maan M. Thabit

Nasma Maan M. Thabit

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 61-85
DOI: 10.33899/rengj.2008.44746

Abstract
Architecture is considered as a language during he last four decades, contemporary studies had presented this trend through different approaches which delt primarily with meaning and signs as semantic expressions in all events. In Mosul, it has emerged in reactions concentrating on architecture relating to continuity and links with social structures which represent the vessel that contains human culture. Hence, there was a strong need to verify various methods and strategies that extent the space surrounding continuity context.
The paper discusses the importance of utilization of implicit symbol concentrating on the architectural reality, in order to explore the particular problem which has been represented as lack of clarity of utilization of implicit symbol in Mosul architecture. Thus, the objective of the paper has been formed and method has been specifies by building theoretical framework consisting of four main items of detailed theoretical field as the following: (what implicit symbol is?, implicit symbol utilization, implicit symbol characteristics and implicit symbol aims). Specify utilization of implicit symbol in architecture firstly, then the application of one of the main items (implicit symbol creation utilization) trends through Mosul architecture secondly, concluding the forms of implicit symbol thirdly.
Finally, conclusions have declared the importance of the role of utilization of implicit symbol in works of Mosul architecture by using many strategies.
Key words: utilization of implicit symbol, Mosul Architecture

Performance Improvement Of Cellular Systems Using MIMO-OFDM

S. A. Mawjoud; W. M. Abdul-Latef

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 69-79
DOI: 10.33899/rengj.2008.44733

The combination of multiple-input multiple-output (MIMO) system with OFDM techniques is regarded as a promising solution for enhancing the data rates of next-generation wireless communication systems.
SDM is implemented to transmitted different signals simultaneously at the same carrier frequency and to detect the transmitted signals using many techniques such as zero frequency, minimum mean square error with and without decision feedback and maximum likelihood decoding.
Furthermore, orthogonal frequency division multiplexing technique included in the simulation process using the parameters of the IEEE 802.11a standard. The fading channel is modeled by exponentially – decayed Rayleigh fading channel which is based on the indoor WLAN, Least Square (LS) method is used to estimate the channel for each subcarrier.

Keyword: WCDMA, MIMO-OFDM.

Fpga Design And Implementation Of A Scan Conversion Graphical Sub-System

Amar I. Dawod; Fakhraldeen H. Ali

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 80-92
DOI: 10.33899/rengj.2008.44735

Abstract
One Major modeling primitive in the field of Computer Graphics is a planar polygon. This polygon can have an arbitrary number of vertices and different shapes. In this paper a graphic sub-system is designed and implemented using Field Programmable Gate Array
( FPGA ). One of the main tasks of the hardware designed is scan-converting convex planar polygons required to update an image in the image memory or video RAM which is used as a Frame Buffer. A facility to read the pixels (Picture Elements), from the frame buffer, for display on the monitor of the computer is also included in the design.
Keywords: frame buffer, scan-conversion, polygons, pixels, FPGA

A Pipelined Fault Tolerant Architecture for Real time DSP Applications

Ahmad Falih Mahmood

AL-Rafdain Engineering Journal (AREJ), Volume 16, Issue 4, Pages 93-102
DOI: 10.33899/rengj.2008.44737

Abstract
This paper presents a new, expandable, pipelined linear array architecture designed for transparently tolerating processor failures for real-time DSP applications. The proposed system use twelve TMS320C40 DSP processors ( Processor Modules PMs ) to construct ten stages pipelined system with two spare processors (SPs). However, the system can be expanded to increase the pipeline stages and the performance, and adding more spare processors to increase the dependability and reliability of the system. In Proposed scheme, the system can automatically reconfigure itself in the event of failure in one or two of its DSP processors and the computations continue unhindered without noticeable performance degradation. Each DSP processor communicates with neighboring processors through a high speed communication ports ( commport ). Some of these commports in every processor are used as a bypass links in case of failure of one or two processors. The system uses the forward-task-shift (FTS) mechanism to tolerate the fault by assigning the function of the failed processor to the next fault-free processor.

Keywords- Linear processor array, fault tolerant, bypass links, pipelining, TMS320C40, DSP processors.