Print ISSN: 1813-0526

Online ISSN: 2220-1270

Volume 18, Issue 6

Volume 18, Issue 6, Summer and Autumn 2010, Page 1-104

Effect of High Temperature on Engineering Properties of Light Weight Blocks Concrete

R. B. Abdurrahman; Z. A. Mohammed; Dr. A. H. Ahmed

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 1-9
DOI: 10.33899/rengj.2010.35165

Light weight concrete blocks have an important role in the last years for it is practical and economical benefit in the building construction. An It has light density providing high thermal insulation and less dead load normally all light weight concrete has fire resistance in its nature, as well as, these type of light weight block has the ability to support quite large amount of load and relatively easy to work and can be cut and shaped with hand tools.
The effect of high temperature on light weight concrete blocks was studied after exposure to (150,350,550)ºC for one hour. The effect of the method of cooling after heating (by air or water) on the compressive and flexural strengths were studied and compared together. The water absorption capacity was also measured during the process of water cooling. The compressive strength relatively increased with high temperature and air cooling , and also increased with measuring the exposed time up to (90) minute, above this time the compressive strength decreased. For water cooling the compressive strength trend to decrease . Flexural strength is decreased as the exposed temperature increased in all cases.
Key words: Concrete ,Light Weight Concrete, High Temperature.


Dr. Mohamad N. Mahmood; Ayad B. Behnam

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 1-14
DOI: 10.33899/rengj.2010.34783

In the present work a formulation of the reinforced bars and prestressed tendons embedded in the brick element is developed and used for the nonlinear analysis of reinforced-prestressed concrete beams. The reinforcement and prestressing bars are represented by an axial 3 nodded bar elements embedded into the 20 nodded isoparametric brick concrete element. Perfect bond is assumed between concrete and prestressing steel bars (or tendons) such that displacements and strains of the bars are assumed to be compatible with those of the concrete element. To verify the applicability of the model two prestressed beams are analyzed and the numerical results show a good agreement with the experimental one.

Keywords: Brick element, Embedded bar, Finite element, Nonlinear analysis, Prestressed concrete.

Processing Lightweight Aggregate to produce Lightweight Concrete

Daad Mohamed Daood; Dr.Nadia Salim Esmaeil

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 10-23
DOI: 10.33899/rengj.2010.35172

The modern techniques development used in the production of concrete led to the emergence of types of concrete with different densities compared to normal concrete . This research aimed manufacturing types of lightweight aggregate (coarse and fine) and then the production of lightweight concrete blocks with a good thermal insulation , by using available locally materials . Two types of lightweight aggregate , have been produced by using two methods of manufacturing , first type , where AL-Hadbaa aggregate , produced from Clay , which is on the edge of the Tigris river in Mosul , using 50% Clay and 50% silt , the density obtained about 860 Kg/m3 . The second AL-Rabean aggregate , was the adoption of natural laminated Clay which is located in Nineveh province , in very large quantities , it's mineralization is Montmurlite and kaolinite , density obtained was 750 Kg/m3 , this type did not produce in Iraq and which it's manufactured method simple and economic . The standard tests have been made and were adopted in the production of concrete blocks , lightweight concrete block produced from AL-Hadbaa aggregate , used in bearing walls , have 28 – day compressive strength 15.33 N/mm2 and density about 1770 Kg/m3 .
The AL-Rabeaan aggregate used to product concrete block for the purposes of thermal insulation , it's thermal conductivity coefficient was 0.55 W/m.kcal and have a density 1640 Kg/m3 .
Keywords : Clay , lightweight aggregate , concrete block


Rabi M. Najem

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 15-27
DOI: 10.33899/rengj.2010.34788


In this research , the formulation of optimum cost design for one way reinforced concrete slabs is presented , since it is useful and have a widespread usage among practicing engineering and applied to realistic structures subjected to the actual constraints of commonly used design codes such as the American concrete instituted code (ACI,2005).

The formulation contains minimizing an objective function that represent the cost of steel reinforcement and the cost of concrete , which is subjected to many constraints containing : flexural constraints , serviceability constraints and deflection constraints that illustrated with details in this paper . the optimum solution is calculated using the lagrangian multipliers method , and a visual basic computer software were developed to find the optimum solution .

Key Words: Optimization , Lagrangian Multiplayer , Optimum Cost Design . One way Slabs .

Behavior of Lime Stabilized Gypseous Soil Beams Under static Loads

A.H. Al Zubaydi; M. T. Al- Layla Professor

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 24-39
DOI: 10.33899/rengj.2010.35180

This work aims to study the stress-strain curves of soil samples subjected to tensile stress. The samples (50*50*300 mm) were prepared from lime stabilized gypseous soil using (3%) lime as stabilization percent. The samples were cured at (25,49 and 600C) for a period of (2,15,30,90 and 180) days. The results obtained from flexural tensile tests were analyzed using three methods of analysis. These methods are, the elastic bending theory, direct, and differential method. The elastic and the direct methods gave, generally similar results of the soil flexural tensile stress while the differential method gave lower values. Also the tensile stress-strain curves obtained by the elastic method were consistent, while the curves from direct and differential methods are in consistent, with the exception of the samples compacted at the dry side of the compaction curve.

Modeling of ultimate load for R.C. beams strengthened with Carbon FRP using artificial neural networks

Dr. Salim T.Yousif; Majid A. AL- Jurmaa; Majid A. AL- Jurmaa

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 28-41
DOI: 10.33899/rengj.2010.34813


The use of carbon fiber reinforced composite materials is an accepted technology that is being used in practice to strengthen existing reinforced concrete (R/C) elements. An artificial neural network (ANN) model was developed using past experimental data on flexural failure of R/C beams strengthened by carbon FRP. The input parameters cover the carbon sheet properties, beam geometrical properties and reinforcement properties; the corresponding output is the ultimate load capacity. The ANN prediction and the measured experimental values are compared with load prediction of ACI440.2R-02 formulas. A sensitivity study of parameters that affect ultimate load of R/C beams strengthened by carbon FRP is carried out. It is concluded that ANN can predict, to a good degree of accuracy, the ultimate load capacity of R/C beams strengthened by carbon FRP and it is a viable tool to carry out parametric study of flexural behavior of R/C beams strengthened by carbon FRP.

Keywords: carbon FRP, Reinforced Concrete Beam, Ultimate Load, and Neural Network

Frequency Analysis of Hydrologic Drought (Case Study)

Dr. Kamel A. Al-Mohseen

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 40-52
DOI: 10.33899/rengj.2010.35187


In this paper, the possibility of studying the occurrence probabilities of hydrologic drought events has been explored. The obtained results were based on the case study of the annual inflow to Fatha discharge station on Tigris river, Iraq, over the period (1931-1988). This recorded time series is basically used to evaluate the observed duration and severity of the drought. The theory of runs is adopted to estimate, both, the probabilities of duration and severity of the drought. Three stochastic models have been used for modeling the hydrologic process having short-term time dependence to generate additional data for statistical inferring of the drought duration. Models such as(AR(1),AR(2),and ARMA(1,1))have been formulated by means of modern techniques called (SAMA-2007). The number of the generated series was ranging between 100 to 10000 series. This help in the estimation of the probabilities of drought severity for which no rigorous mathematical solution is exist yet. Discrepancy in the performances of the proposed models have been noticed, especially in their capabilities of preserving the statistical properties of the observed time series. It is concluded that while a certain model has a satisfactory performance in preserving certain parameters, it failed in the estimation of other parameters.

(Keywords: Drought, Stochastic Modeli

Gap Acceptance, and Traffic Safety Analysis On U-Turn Median OpeningsOf Arterial Roads

Dr. Abdul Khalik Al-Taei

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 42-53
DOI: 10.33899/rengj.2010.34824

In this study, eight locations on U-turn median openings in Duhok City were investigated about gaps or lags of traffic opposing and delaying traffic turning left. Other data was collected from the scene like conflicts with turning traffic, travel speed, and volumes of opposing and parallel flow. Accident frequency experienced near U-turn openings location for three years (2005-2007) was collected too.
Analysis of data using statistical methods show different empirical models correlating independent variables like , gap length travel speed , traffic volume , approach width , conflict rate…etc. with dependent variables like , delay time , accident rate , and percentage of drivers accepting or rejecting gaps . Average lag obtained to control safety of studied locations was 3.5 sec.
Key Word: Gap Acceptance, Duhok


Dr.Eman Hazim Sheet

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 53-60
DOI: 10.33899/rengj.2010.35198

A mathematical optimization model for optimum weekly irrigation water requirements for maize crop at Mosul area is developed. The main objective function is to maximize profit. The growing season is divided into (17)weeks with constraints on actual evapotranspiration, soil moisture at the root zone and deep percolation. The total amount of irrigation water requirements is assumed known and limited at the beginning of the season. The results of this approach was compared with a previous simulation model for irrigation water requirement. It is found that optimization model reduce seasonal irrigation water by 13% compared with simulation models. The proposed model is simple for predicting weekly irrigation requirements and can be used for any crop by changing crop data. where simulation models take longer time and do not give optimal solutions. As this model is applied to many crops grown over large areas, a huge amount of irrigation water may be saved

KEYWORDS:optimization ,irrigation scheduling, optimal yield

Handoff Priority Schemes in Wireless Mobile Cellular System

H. A. Al-Tayyar; S. A. Mawjoud

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 54-60
DOI: 10.33899/rengj.2010.34852


Handoff operation, algorithm and modeling is vital in wireless cellular system. Two fundamental handoff procedures exist. The first model concerning the propagation environment and the second model is the limited channel resources which is dealt with in this paper. A realistic model of guard channel priority representing mobility is suggested and simulated.
Keywords: Wireless network, Handoff priority schemes.

Mole Fraction Effect on Semiconductor Optical Amplifier Specifications

Khalis A. Mohammed

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 61-69
DOI: 10.33899/rengj.2010.34862

Semiconductor optical amplifier had been studied theoretically using the traveling wave equation. The study took into consideration the many parameters that could affect the operation of amplifier, such as mole fraction, noise figure and material gain have been studied theoretically for the suggested amplifier in the wavelength of 1.55 m. The results show that gain material peak was shifted when injected current and wavelength were varied. An interesting result of the noise figure was found to be minimum at the operating wavelength of 1.55 m.
Keywords: Amplifier noise, noise, noise figure, noise measurement, wideband semiconductor optical amplifiers.

The Efficiency of the Spatial Distribution of Civil Defense Stations in Mosul City

Ahmed A. Alfakhry; Dr. Turki Hassan Ali; Faris Attallah

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 61-104
DOI: 10.33899/rengj.2010.35204

Civil defense stations in cities are one of the basic emergency services that should be considered in mind of every urban designers and planners who is going to design and develop any city , because of the urgent need to provide safety requirements against fire
The construction and building activities in Mosul city had witnessed a great expansion with high rate increase in number of its population in the last decades, this increase in population growth had not accompanied by provision of the essential services needed by the city because of the known circumstances that prevailed in Iraq and its cities during the past period.
This led to increase pressure on the service activities in the city and worsening the outcome of such infrastructure services, from those the firefighting and rescue services. So the fulfillment of civil defense stations provision and its distribution requirements has become one of the necessities that the designers should be addressed and solved.
This research, study the efficiency of spatial distribution of civil defense stations in Mosul city, its number, and positioning according to the actual need, based on the available local and international standards.

FPGA Based Implementation of Convolutional Encoder- Viterbi Decoder Using Multiple Booting Technique

Yahya Taher Qassim; Dr. Dhafir A. Alneema

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 70-80
DOI: 10.33899/rengj.2010.34888

Convolutional encoding is considered one of the forward error correction schemes. It is an essential component of wireless communication systems such as the third generation (3G) mobile systems, which utilize some formulation of Convolutional encoding usually decoded via Viterbi decoders. There are different structures of Convolutional encoding which impart different requirements on the decoder. The Viterbi decoder segments with slight modifications can be used on systems with different constraint lengths, frame size and code rates. In this research, the design and implementation of Convolutional encoder with constraint length 3 and rate 1/2, and Viterbi decoder on Spartan 3E FPGA Starter kit (supported with XC3S500E) using multiple booting technique has been presented. VHDL language is used as a design entry. In the starter kit mentioned above, two designs are implemented on the flash memory using the multiple booting technique: the Convolutional encoder and the Viterbi decoder. The FPGA is configured with the specified design depending on the loaded program from the Intel flash memory. With this way of configuration, the FPGA itself can operate as a Convolutional encoder or Viterbi decoder that gain benefit through the reuse of the same hardware.
Key words : Convolutional encoder, Viterbi decoder, multiple booting technique and FPGA.

Design and FPGA Implementation of Takagi- Sugeno Fuzzy Controller Based on LUTs

Rasha Ilham Majeed

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 81-94
DOI: 10.33899/rengj.2010.34908

In this paper, an approach for designing Fuzzy Controller based on Takagi-Sugeno inference engine with high computational speeds in architecture is proposed. The work focuses on advantages and disadvantages of Takagi-Sugeno control as compared with Mamdani's', in addition to focus on how computational complexity of the inference engine can be reduced and the speed of computation can be increased. Fuzzy Controller is implemented on FPGA using Look-Up Table (LUT). Whereas, each LUT is represented by Block RAMs in FPGA besides using number of arithmetic units in the design. To interface the design with users, a GUI program is designed using Visual Basic. Using JTAG port, the GUI's data can be stored in Block RAMs. Later, a designed Air Conditioning application is implemented and the practical results (in FPGA), theoretical results (computed by hand) and Matlab results are compared.
Keywords: LUT, FPGA, JTAG port, Takagi-Sugeno Fuzzy Controller, GUI.


Dr. F. M. Abdulla; A. M. Ali; H. A. Ibrahim

Al-Rafidain Engineering Journal (AREJ), 2010, Volume 18, Issue 6, Pages 95-104
DOI: 10.33899/rengj.2010.34930

The effect of deformation on the corrosion of galvanized high strength low alloy steel sheet is studied. Specimens in the uniaxial, plain and biaxial strains were stretched by a hemispherical punch to three different punch heights for each path of strain. After each deformation, The deformed specimens together with a fourth non deformed specimen were subjected to a corrosive medium for the same sequential times. To determine the effect of corrosion, all the specimens were weighted before and after each corrosion stage and the hardness was also measured It was found that corrosion in the deformed specimens was higher than in the non-deformed ones. Also it was found that corrosion increased by moving from the uniaxial to the biaxial strain passing through the plain strain path and by increasing the punch heights. The results were verified by the hardness measurement.

KEYWORDS: galvanized HSLA steel, corrosion, deformation, strain path