Print ISSN: 1813-0526

Online ISSN: 2220-1270

Volume 21, Issue 2

Volume 21, Issue 2, Winter and Spring 2013, Page 1-117

Effect of Some Variables in Heat of Hydration in concrete

Z. M. Sh. Ibrahim; Prof. Dr. Kh. A. Zakaria

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 1-11
DOI: 10.33899/rengj.2013.72710

In this research, the effects of some parameters on the heat of hydration for two concrete mixes have been studied. The mixes are with and without 15% micro silica as a cement weight replacement designated (M2) and (M1) respectively, and Three concrete mixes by weight namely, (1:2:4 , 1:1.5:3 , and 1:1:2) at uniform consistency that is a constant slump of (75-100 mm) for both(M1) and (M2), and Two curing methods, moist and air cured, While the internal temperature for the specimens was measured for (28) days : at the 1st two days at intervals of half an hour then at intervals of (3 hrs) for the 3rd and 4th day, while at intervals of (6 hrs) until (28) days. The results of the research proved that the heat of hydration was higher at the 1st day than that at the 2nd day, fluctuating during the 1st (48 hrs) . The fluctuation reduces gradually to a steady rate at later ages, While the heat of hydration for all mixes and at all ages (except the 1st day) was higher for air cured specimens than that moist cured for same condition, As the cement content increased the heat of hydration (for mixes M1) increased accordingly and also the addition of silica lowered the internal concrete temperature for M1 mixes (at high and moderate cement contents) in opposite of few cement contents.

Comparison between a Heat Pipe and a Thermosyphon Performance with Variable Evaporator Length_ENG

Dr. Hussain H. Ahmad; Anwar A. Yousif

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 1-12
DOI: 10.33899/rengj.2013.72814

Heat pipes and two phase thermosyphons are heat transfer devices whose operating principles are based on the evaporation/condensation of a working fluid using the capillary pumping forces (in the case of heat pipe) and gravity forces (in the case of two phase thermosyphons) to ensure the fluid circulation. The two systems were designed and constructed to investigate the performance and the affecting parameters, using ethanol as a working fluid. The affecting parameters which were studied are power input (200≤Q≤700) W, working fluid filling ratios (35% and 85%) and aspect ratio, the ratio of evaporator length to inner diameter, (4.0, 7.8 and11.5) . The experimental results showed that the best performance of heat pipe obtained at aspect ratio (7.8) and (85%) filling ratio at (500) W where the maximum heat transfer coefficient was (9950) W/m2.oC, while for the two phase thermosyphon the best performance was obtained at aspect ratio (4.0) for (35%) filling ratio and power input (600) W with maximum heat transfer coefficient equals to(4590) W/m2.oC. The overall comparison between the two systems showed that the performance of the heat pipe is better than that of the two phase thermosyphon. The experimental results of heat pipe was compared with theoretical and empirical correlations showing reasonable agreement especially with immura with percent 70%.
KEY WORDS: heat pipe, two phase thermosyphon, aspect ratio, filling ratio

Behavior Of Composite Beams (Steel-Concrete) Strengthened By (CFRP) Sheets Under Repeated Loading

Dr. Bayar J. Al-Sulayfani; Islam Abd-Ullah Aziz

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 12-26
DOI: 10.33899/rengj.2013.72723

Present study aims mainly to conduct the behavior of composite beams strengthened with carbon fiber reinforced polymers (CFRP) as they subjected to repeated loads. It investigates the enhancement of load capacity up to failure and the reduction in transverse deflection at the ends of composite beam as affected by (CFRP) strengthening. The following parameters were taken in to consideration in this paper. Location of (CFRP) along the composite beam, Wrapped length effect and effects the Number of (CFRP) layers. From test results it is obvious that (CFRP) is very active in increasing the load capacity by (36%) and reducing the mid span deflection by (56%) in addition to minimizing the slip at beam ends by (98%). Depending on the location, length and number of (CFRP) layers in to account.
Key words:- Composite beams, CFRP, Repeated loads and Slip.

The effect of circular holes on the natural frequencies of a beam using transverse vibration measurements method _ENG

Tariq Khalid Abdilrazzaq

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 13-24
DOI: 10.33899/rengj.2013.72817

Defects influence in a negative way the service life of the structures. Thus, defect detection has been a considerable effort in order to eliminate this effect . In this study, the dynamical behavior of a cantilever beam, with different size of a hole, at different distances from the fixed end-for each case- have been measured, evaluated and compared with that of intact beam. It has been shown that the hole may be considered as a defect in most cases, which leads-in general- to decrease the stiffness, according to its size and place, hence affects the dynamic properties i.e., the natural frequencies and the mode shapes. A simulation process for the modal analysis using ANSYS program(release 12.1) is done in order to compare the results. In addition to that, a theoretical analysis is also done. The experimental results of the intact beam were compared with both the ANSYS program and the theoretical results. They showed an acceptable agreement between the three methods.

Keywords: transverse vibration, fault detection, beam crack, beam defect, beam vibration.

The effect of using Non-Uniform Blank Holder Force in Deep Drawing process on the thickness distribution along the cup_ENG

Alaa Dahaam Younis

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 25-31
DOI: 10.33899/rengj.2013.72818

In this paper, a new concept of blank holder in deep drawing is presented. The aim of this study is to predict the wrinkling and thinning (necking) failure through the study of the effect of using constant, variable and non-uniform blank holder force(BHF) between the blank and blank holder on the thickness distribution along the cup (wall, base and nose). Numerical modeling were carried out on various values of blank holder force (BHF) (i.e., Constant-Uniform, Variable-Uniform, Constant Non-Uniform and Variable Non-Uniform). The simulation results shows that the best value of blank holder force were achieved at Variable Non-Uniform type; which gives the smallest difference between maximum and minimum thickness distribution along the cup.
Key wards: ANSYS 11, Deep Drawing, Blank holder force

Mechanical Properties of High Strength Steel Fiber Reinforced Concrete

Dr. salim T. Yousif; hisaan Shams-aldeen

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 27-39
DOI: 10.33899/rengj.2013.72717

In this research, five concrete mixes were prepared, made samples for compressive, Splitting, bending and modulus of elasticity test have been use five of silica fume percentages and three of steel fiber percentages. According to results of this study, addition of steel fiber cause increase in compressive strength, splitting strength, bending strength, modulus of elasticity, and increase the angle of stress-strain curve. Addition of silica fume cause increase in compressive strength, splitting strength, modulus of elasticity, increase the angle of stress-strain curve while cause decreasing in bending strength. The higher compressive strength percentage was (32%) as compared to reference sample prepared at ninety days with silica fume percentage (5%) and steel fiber (0.5%), The higher percentage for splitting strength was (42%) while the highest percentage for modulus of rupture (33%), The highest ratio for modulus of elasticity (27%).
Keywords: High strength concrete, Steel fibers, Silica fume, mechanical properties

Performance Evaluation study of Hybrid Generation System (Microhydro + Diesel) in Iraqi Remote Rural Electrification_ENG

Prof.Dr. M. F. AL Kababjie; W. H. Hamdon

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 32-41
DOI: 10.33899/rengj.2013.72823

This work highlights the benefits and advantages of using Micro Hydro Power Plants (MHPP) in electrification the rural areas, which they are remote from the electric grid and locate beside the river. In these areas Electrical Energy is generated, if any, by diesel generators. This work presents the Performance evaluation and feasibility study as well as environmental effect of adding a Micro Hydro electrical generation unit to two diesel generators used for electrification an Iraqi remote village. Homer software from National Renewable Energy Laboratory (NREL) – USA is used to simulate the system to obtain the optimum hybrid power system configuration. The results of simulation show that the hybrid power system can reduce the cost of electric power unit (kilowatt / hour) as well as reducing the level of air pollution and noise compared to the stand alone diesel system.
Index Terms: Hybrid Generation System, Micro-hydropower, HOMER, Renewable energies, Rural electrification, Environmental effects.

Modulus of Rupture of Fully and Partially Reinforced Concrete Beams With Polypropylene Fibers

Samer Sami Majeed

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 40-51
DOI: 10.33899/rengj.2013.72714

Abstract: -
In this research an experimental study was conducted to explore some mechanical properties such as compressive strength and splitting tensile strength and modulus of elasticity of concrete mix with weighted mixed portions (1 : 1.5 : 2 / 0.35) reinforced with polypropylene fibers by (0.25%, 0.50%, 0.75%, 1.0%, 1.25%) as volume percentage comparing with normal concrete. Research also contain testing modulus of rupture and maximum deflection of polypropylene concrete beams with dimensions (100×100×500) mm with the same volume percentage and concrete beams with half depth fibrous concrete and the other half normal concrete and comparing with the modulus of rupture and maximum deflection of normal concrete beams.
Keywords: Compressive and Tensile strength, Deflection in beams, Modulus of elasticity, Modulus of rupture, Polypropylene fiber.

UWB MB-OFDM 4-Parallel Radix2 FFT Performance Analysis_ ENG

Dr. M. J. Mohammed; B. M. Ahmad; Dr. K. M. Quboa

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 41-53
DOI: 10.33899/rengj.2013.72851


The Ultra Wide-Band Multi Band-Orthogonal Frequency Division Multiplexing (UWBMB-OFDM) systemis a low power (– 41.3 dBm/MHz); short-range (less than 10 m); high speed (53.3 - 480 Mbps) wireless technology with spectral band widthfrom 3.1GHz to 10.6 GHz allocated by Federal Communications Commission (FCC) according to IEEE 802.15.3a standard. The UWB spectrum is divided into 14 subbands, each with 528 MHz bandwidth . Each OFDM symbol is transmitted / received a cross each subband using a single 128-point radix2 IFFT/FFT.
In this paper a simulation software is written using Matlab version 10 to evaluate the Bit Error Rate (BER) of the system using the traditional 128-point IFFT/FFT algorithm, and the proposed 4-parallel 32-point radix2 IFFT/FFT algorithm. It has been shown that a time saving is 28.7 % , and that the BER is better off 5dB using the proposed method as compared to traditional method.

Pressure effect on wetting pattern in layered soil for subsurface point source

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 52-63
DOI: 10.33899/rengj.2013.72799

Laboratory experiments were carried out to investigate the effect of operating pressure on wetting pattern in layered soil for subsurface point water source. This study helps to determine a suitable operating pressure and appropriate spacing between emitters and drip lateral pipes . The layered soil profiles were prepared using two types of soil (clay and loam) in two combinations (clay over loam and loam over clay) . Three operation pressures (4.99, 9.99 and 16.14, m) with a nominal dripper discharge rate (2 l/hr) were used . The experimental results showed that positive back pressure around dripper outlet develops, when the water application rate is larger than the soil infiltration capacity , and the actual dripper discharges were less than the rated dripper discharges by about (10%-28%) due to back pressure effect . Furthermore, it has been observed that water start rising up to the soil surface (Chimney Effect) when the operating pressure is (16.14m) for the loam over clay soil profile, which occurs when water application rate exceeds the soil capability to spread the water. It is found that the total wetted area for both layers was not affected by the operation pressure for the same volume of applied water . In the relationship of the wetting advance (a tb) , it is found that , the constant (b) is not effected by operation pressure while the constant (a) increased with increased operation pressure .

Assessment of Uplink Time Difference Of Arrival (U-TDOA) Position Location Method in Urban Area and Highway in Mosul City_ENG

Yehia R. Hamdy; Dr. Sami A. Mawjoud

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 54-65
DOI: 10.33899/rengj.2013.72854

The aim of this paper is the assessment of the performance of U-TDOA Position Location (PL) method on a UMTS cellular system in Mosul city, Iraq. The study area is a (3×3 km) which covers the University of Mosul campus. Simulation is used to study and evaluate the performance of U-TDOA PL method in urban area and on a highway inside the city. The effect of terrain, multipath, signal to noise ratio (SNR), Geometric Dilution Of Precision (GDOP), shadowing and the configuration of base stations on the positioning accuracy are investigated. The study is conducted on a real coordinates with the distribution of UMTS BSs as the same existing 2.5 Generation Enhanced Data rates for GSM Evolution (EDGE)Asiacell operator.
Keywords: U-TDOA, Position Location, UMTS.

Gross Irrigation Water Requirement for Durum Wheat Crop (Sham 3) At Mosul Area In Season 2009/2010

Ahmed Azhor Thanoon

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 64-72
DOI: 10.33899/rengj.2013.72800

This study aims to determine the gross irrigation water requirement GIWR for durum wheat crop (Sham3) using climate , crop, and soil in Mosul area .
The experiment was carried out in the field of the technical institute of Mosul for the cultivation durum wheat crop cv.Sham3 in season 2009/2010.
The consumptive water use was determined by multiplied the calculated reference crop evapotranspiration using Penman-Monteith equation based on climatological data for Mosul station which considered the nearest to the experiment , by a crop coefficient depended on the growth of stages ( initial , development , mid , and end stage) .
The GIWR was 175 mm.season-1 and determined based on the effective rainfall, consumptive water use , change in soil water storage in root zone , and efficiency of irrigation . Four irrigation treatments were used 100% , 50% , 25% from GIWR , and without irrigation , only rainfall .The results showed that the crop properties such as the grain yield increases with irrigated in full GIWR and reached to 5.5 t/ha ,While it decreases by 20% with irrigated in 50% from GIWR .

Keywords: Irrigation water requirement, Penman-Monteith, Durum wheat, Mosul.

Design and MultiPlierless Realization of ECG- Based Gaussian Wavelet Filter with Lattice Structures_ENG

Dr. Jassim M. Abdul-Jabbar; Abdulhamed M. Jasim

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 66-77
DOI: 10.33899/rengj.2013.72855

In this paper, the Gaussian function is selected as a mother wavelet function and utilized in the design of some corresponding filter banks. With a 1st derivation of the Gaussian function, a similar shape to QRS complex part of the ECG is achieved.It can be used for QRS feature extraction.Using thesymmetry property of the mother wavelet function, the designed FIR wavelet filter banks can be realized in highly-efficient lattice structures which are easy to implement. The resulting lattice structures reduces the number of filter banks coefficients and this reduces, in turn the number of multiplications and improves the filter banks efficiencies as it reduces the number of computations performed. Hardwarely, this leads to less-complex implementations. The resulting quantized multiplier values also lead to a multiplierless realization for such wavelet filter banks.
Keywords: ECG,Wavelet and scaling functions, Filter banks, Lattice structures, Multiplierless realization.

Optimal Neuro-Fuzzy D.C. Motor Speed Control

Assist lecture. Hameed A; Assist lecture. Hameed A

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 73-86
DOI: 10.33899/rengj.2013.72801

This work deals with investigating of d.c. motor speed controlled by a buck-boost converter. Open loop system is tested. Aneuro-Fuzzy controller with random number and type of membership function is designed to control the speed of the d.c. motor as a closed loop system. Because of the lack of a clear and a known way for selecting the type and number of membership function in case of fuzzy control, An Adaptive Neuro-Fuzzy Inference System which comprises a fuzzy inference structure and neural network learning ability is modified to control the speed of the motor. The technique is used to select the optimal number and the best type of membership function for the fuzzy system. The process is carried out through testing four types of membership functions with different numbers (3,5,…etc) for each type and computing the absolute error for each case comparing their results to choose the smallest among them. Then the chosen root is applied to control the system for the rest time of control. The technique is applied to two loads (motors).

FlexuralStrength of Reinforced Concrete Slabs Strengthened and Repaired by High StrengthFerrocement at Tension Zone_ENG

Mohammed N. Mahmood; Hassan SideqThanoon

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 78-89
DOI: 10.33899/rengj.2013.72859

This paper presents a study of the flexural behavior of strengthened and repaired reinforced concrete slabs by ferrocement. The study includes testing 17 simply supported slabs, which include 2 control slabs, 3 strengthened slabs and 12 repaired slabs. In the strengthenedslabs the effect of number of wire mesh layers of ferrocement on the ultimate load, mid span deflection at ultimate load and intensity of cracks were examined. In the repaired part the slabs were stressed to (70 %) of measured ultimate loadof control slab. The effectsof number of wire mesh layers, ferrocement thickness and the connection method between repaired slabsand ferrocementjacket on the ultimate load, mid span deflection at ultimate load and intensity of cracks were examined.
Keywords: Concrete, ferrocement, repair, slab, strengthening

Performance and Heat Transfer Characteristics in Loop Thermosyphon (An Experimental Study)

Dr. Hussain H. Ahmad; Hareth M. Abd

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 87-98
DOI: 10.33899/rengj.2013.72803

A Loop Thermosyphon has been designed, fabricated and tested to investigate the heat transfer characteristics by two-phase natural convection. The rig was made from copper tubes connected with each other in closed loop including four main parts: vertical evaporator located in the bottom of the device and surrounded by an electrical coil heater as a heat source ,a horizontal condenser located in the upper part of the device cooled by water, vapor rising adiabatic tube and condensate return adiabatic tube. In this research the effect of heat input and filling ratio of the evaporator on the heat transfer coefficient and temperature distribution on the loop surface was verified experimentally using distilled water as working fluid at operating pressure near-atmospheric pressure. The maximum heat transport capability for evaporator was found to be equal to (3424 W/m2 oC). A comparison between the present work results with empirical and theoretical correlations of other researchers showed good agreement.

Urban micro-climate in the City of Mosul, Iraq (The Effect of Urban Space Characters on Air Temperature) _ENG

Turki Hassan Ali; Bahjat Rashad Shaheen

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 90-97
DOI: 10.33899/rengj.2013.72861

The proportion of the world's population living in urban areas is constantly increasing. Different urban shapes result different micro-climates. The way cities are planned and build is therefore important for the global energy use. The city of Mosul ( north of Iraq) had witnessed a rapid urbanization during the second half of the last century, adopting the open grid iron system in planning the new residential areas which now exist beside the traditional compact system. This study present result from measurements of Max. air temperature during hot season in (156) points in the traditional paths of the old city (called zuqaqu) and (44) points in the streets of the modern neighborhoods, more over the engineering-physical characteristics of each point had been measured. Using statistical analyzing for determining the impact of each of these characters on the urban micro climate (Max. air temperature).The primary results show that sky view factor has the major impact on air temperature, and that confirm the important role of the urban designers and planners in the urban micro-climate. Key words: urban micro-climate, traditional city, Mosul.

The impact of design concepts on thinking performance in urban design studio

Dr. E. H. Alallaf; H. H. Alsoofe; Dr. N.T. Alkymakchy

Al-Rafidain Engineering Journal (AREJ), 2013, Volume 21, Issue 2, Pages 99-117
DOI: 10.33899/rengj.2013.72808

Design concepts play a crucial role in guiding the mental action during the design task, because they represent the media which support the design goals and strategy, these concepts are vary according to the design circumstance, the type of building and the designer. It is difficult to capture these concepts through the design product in architecture and urban design that due to the difficulty of conceptual perception by the designer and the difficulty of delivering overall conceptual message from architect to others. This problem exacerbate in the students design behavior in architectural study, due to the inadequacy of the experience that they enjoy in the design work, and inappropriate election of the concepts to solve the design problem
This research attempts to draw the design action and its change during a design experiment carried out by students in the final stage of architectural study (in urban design studio), to highlight the variation between this action and the change of design concept to indicate preferences elements of this concept by the student in the message delivery to the recipient, and thus his/her success in completing the work.
The research tries to measure the thinking performance of the student within eight design sessions, through classifying design concept submitted by him/her and drop it into (Rasmussen) model of thinking performance Finally the research will try to find obstacles in the election of certain types of design concepts in urban design projects on the total thinking production.
Keywords: design concepts, architectural education, design thinking, productive thinking