Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 31, Issue 5

Volume 31, Issue 5, April 2013, Page 87-1010

The Effect of Atomizer Position in a Curved Duct on the Humidification Process of Steadily Flowing Air

Hussein Hayder Mohammed Ali; Abdul Satar Jawad Mohammed; Sabah Tarik Ahmed

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 793-815

An experimental study is conducted on the utilization of water atomization to evaluate its impact on the humidification of steadily flowing air travelling throughout a curved portion of a uniform cross sectional duct. One of the more interesting aspects of curved channel flows is the introduction of a secondary flow pattern in the duct cross-section. The naturally generated turbulences in air flow will certainly assist the mixing between the air and the injected water droplets and improve the heat and mass transfer process encountered in evaporative cooling of the incoming air drought.
The present study is considered as a simulation of the gas turbine inlet air cooling by the fogging technique. The drier the air, the better the humidification and cooling process. At higher ambient temperature of 43oC, an increase in the relative humidity of 67.8% and a temperature reduction of 39.6% were recorded at higher water atomizer rate of 24.2ml/s. Generally, the lower half of the curved duct is shown to be less sensitive to the atomizer position for a range of inclination angles between 10o to 45o with radial locations between 5 to 20cm from the inner wall. This situation makes this region most suitable for using atomizing array across it in order to give acceptable performance for cooling system. Nevertheless, the upper half of the curved duct introduces a critical atomizer position suitable for single point spray. This position is considered as the optimum atomizer position defined by a radii ratio of (r/rin = 3.2) and an orientation of -10o to the tangential flow.

Mathematical Estimation for the Bearing Capacity of Sand Column Inserted in Soft Clay Soil

Awf Abdul Rahman Al-Kaisi; Hiba Hussein Ali

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 816-827

Sand column is one of the soft ground improvement methods. It is made up of well compacted sand pile, it is used for enhance the load capacity of soft clay soils, reduce the settlement and accelerate the consolidation process of the native soft soil surrounding it, also the sand column is used to minimize the likelihood of liquefaction when installed in loose sand soils.
This research deals with the evaluation of a mathematical equation depending on the results obtain from series of triaxial test in order to calculate the bearing capacity of sand column which inserted in soft clay soil and for two different cases (floating case condition and other is when the sand column is resting on a firm base).
The results indicate that the calculation of the shaft resistance for sand column mainly depends on the clay medium properties, while the calculation of the end bearing depends on the sand property (depending on the mode of failure for the sand column, which was observed). Another group of mathematical relations was suggested to calculate the load capacity of sand column inserted in soft clay for two area replacement ratios (11% and 6%) and depending on the confining pressures considered (100-400) kPa, and for two cases, the first is when the sand column in the floating case condition and other is when the sand column is resting on a firm base.

The Challenges of Water Sustainability in Iraq

Abdul Hameed M. Jawad Al Obaidy; Mukdad Al-Khateeb

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 828-840

The sustainable development in Iraq is being hindered by several obstacles. Water, being related to the food security, is a main concern that could duplicate the already present socio-economic dilemmas. Unless practical measures are immediately initiated, the consequences are expected to demolish the development achievements, though so modest, and become a real threat to the lives of the Iraqis within the near future. This paper aims to present a holistic view at the current development challenges and to concentrate on the socio-economic challenges to water sustainability in Iraq. Also, stresses on the need for a comprehensive national plan for the conservation of water and other natural resources and how to reverse the environmental challenges into practical opportunities for sustainable development.

Effect of Boundary Conditions on Impact Resistance of Concrete Slabs

Eyad K. Sayhood; Nisreen S.Mohammed; Sabah K. Muslih

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 841-860

A theoretical analysis based on the numerical solution of the slab impact integral equation is carried out to determine the impact force and deflection time histories, the strain energy absorbed by the slabs and the maximum bending moment.
Effect of slab boundary conditions on impact response of slab is also discussed. The theoretical results obtained in the present analysis are compared with experimental and theoretical works previously done. A good agreement is found between theoretical and experimental results. This indicates that the impact resistance of relatively large slabs may be predicted by using the theoretical approach based on equation of undamped slab vibration. All the derivations required to predict the effect of boundary conditions are performed for both forced and free vibrations. For the same falling mass and the same applied kinetic energy (height of drop) for all cases, the maximum central deflection and the maximum impact force are affected by the boundary conditions of the slabs

Experimental Study of the Influence of Baffles on Hydrodynamics of Gas- Solids Fluidized Bed System

Jamal M. Ali

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 861-878

The objective of the present study was to determine the effects of the internals baffles on the gas-solids fluidized bed hydrodynamics, using a circular fluidized bed of Geldert group B sand particles.
Bed expansion data were obtained for un baffled and two different types of baffled (rectangular and circular blades) gas-solids fluidized beds at varying operating conditions, namely air velocity ,particle size (755,424 , 205µm) and initial static bed heights.
Experimental work was carried out in (0.1m) diameter and (1m) height circular fluidized bed column.
The results of the study showed that the particle size affects the measured hydrodynamic behavior especially in the large particle size.
The insertion of baffles into a fluidized bed system improves the contacting efficiency of gas and particle phases.
The effect of rectangular baffles is more significant than the effect of circular baffles on the pressure drop in fluidizing bed.

Empirical Modelling for Prediction of Work piece Surface Roughness and Cutting Tool Temperature in Turning Carbon Steel

HaiderM. Mohammad; Murtadha A. Jabbar

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 879-889

To increase cutting tool life and improve workpiece surface quality, an empirical model was proposed to predict workpiece surface roughness and cutting tool temperature by discovering an empirical equations that depends upon the experimental results of turning carbon steel. These empirical equations predict values; and describe the behaviour of workpiece surface roughness and cutting tool temperature. The experimental work involves turning carbon steel (ASTM Standard A105) by measuring workpiece surface roughness and cutting tool temperature at different cutting speed, feed rate, and depth of cut that consider the major cutting parameters. The results indicated that cutting speed and feed rate has a major effect on workpiece surface roughness and cutting tool temperature. Also, a comparison between experimental and predicted results was made, which show a good agreement, i.e the correlation coefficients reached to 0.9894 for surface roughness and 0.9943% for temperature.

Fracture Energy Influence on the Behavior of Steel Fiber Reinforced Concrete (SFRC) Beam Using Finite Element Method

Mehdi Ali Jawad Albayyati

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 890-909

The principle aim of this research is concentrated on studying the effect of cracks and their propagations on the mechanical behavior of a steel fiber reinforced concrete (SFRC) beam. High strength concretes are being used more often due to their superior properties but these concretes have higher brittleness, which is a disadvantage. The idea of adding fibers to the concrete mixture to improve the mechanical response gives high strength steel fiber reinforced concrete (SFRC) with high toughness. The effect of steel fiber is introduced in the model by giving the concrete specified high value of fracture energy. Concrete cracking is divided into two major zones; the first one is the fracture zone (a combination of wide bridging zone effect and the cohesive microscopic cracking zone) which obeys a special law permitting the transmission of stress across the two faces of crack, this zone is considered as partially cracked concrete. When crack opening exceeds a specific value , this zone is converted to a real crack (an open crack) and cannot transmit any stress across the two faces of a crack. Using the experimental data obtained from the flexural test on notched beam loaded under three-point bending, where fracture mode I is dominated. The response of the applied load-crack mouth opening displacement (CMOD) with using fracture energy calculated by the test and the cohesive stresses corresponding to their crack openings with different values of steel fiber respectively are drawn. The results show that the fracture zone for SFRC is wider than that occurs in plain concrete for many times. The contributions of plain concrete and steel fiber are being demonstrated.

Measurements in Alhadba Minaret Using Robotic Total Station

Rasheed Saleem Abed; Ghassan Najim Abdullah

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 910-920

The old heritage of Alhadba Minaret in Mosul is famous for its considerable height and leaning. After approximately 800 years since its construction still withstanding degradation. It has to be clearly documented for restoration and maintenance works. Defining geometry and measurements using traditional surveying methods is not feasible due to its height and delicate surface. This paper introduces the results of measurements using robotic reflectorless total station of TOPCON (IS-Imaging Station) conducted in and around the minaret. We present new facts regarding the descriptions of shape and curvature of the minaret body as well as specific notes on using this instrument. These measurements compose a complementary part of data collection effort required for a major preservation project that is proposed to be conducted in the future.

2nd order Incremental Data Weighted Averaging (IDWA) Technique to Reduce In-band Tones of an 8-bit Digitalto- Analog Convertor (DAC)

Hasan M. Azzawi

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 921-931

A second order of IDWA (Incremental data weighted averaging) technique is proposed to improve 8-bit digital-to-analog convertor (DAC). In addition, this paper discusses the impact of mismatch between DAC unit elements. The Proposed IDWA/8-DAC circuits, which results in a completely second order mismatch noise shaping while solving in band tone problem. The simulation results show the effectiveness of the IDWA technique in reduction of inband tones, also IDWA technique proves its ability to solve DAC unit elements mismatch. The inband tones are converted into a broadband. It was found that IDWA algorithm proves its ability to solve this problem. The inband tone reduction is improved 8 dB if, element mismatch, =0.01 and 7 dB if =0.08 with proposed IDWA, thus improving the DAC performance if compared with DAC performance without using IDWA circuit. MATLAB (V.7.12) program is used for simulation.

Performance of Powdered Polymerized Concrete at Elevated Temperatures

Dina Mukheef Hamza

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 932-950

In the domain of concrete modification by using polymers, the present study, focused on the use of Carboxy-Methyl Cellulose (CMC) as a water-soluble polymer and investigate its effects on the behavior of concrete. The study include two issues, the first one is the effect of polymer adding method on mechanical properties of concrete such as compressive strength, tensile strength and modulus of elasticity in additional to impact resistance and the second is the effect of graded temperature on these properties. The polymer/cement ratio used herein is 3%, this ratio never used before in the previous researches on many types of water soluble powder polymers.
Three concrete batches were prepared, the first is the reference one as a normal concrete (NOR), the second is a polymerized concrete (POL1) where the polymer added as a latex, and the last also as a polymerized concrete (POL2) but the polymer added as a powder.Each batch contains twelve cubic specimens (100x100x100)mm for compressive strength test, three cubes for each level of temperature, eight cylindrical specimens (150x300)mm for splitting tensile strength test, two cylinders for each level of temperature, and four paneled specimens (450x450x50)mm for impact resistance test, one panel for each level of temperature.
It can be considered from the results that when the polymer CMC used herein added as a latex will give better strength behavior in polymerized concrete than the one which added as a powder by about 28.86% in compressive strength, 19% in splitting tensile strength, very high percent in modulus of elasticity and 16.66% in impact resistance. On the other hand, it is found that the temperature level of 200°C will affect the behavior of polymerized concrete and that contrast with the behavior of normal concrete while in temperature levels 400°C and 600°C the effects on polymerized concrete will be more slightly and more clearly on normal concrete.

Determination of the Position and the Area of any Spot Using Satellite Images

Ameera Meki Jassim; Hussain Zaydan Ali

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 951-963

The position and the area of any spot can be determined in different modes and using satellite image is one of them. For this mode there are many applications like in determining the positions and the areas of the water pollution spots (the rivers, the streams, the marshes….etc.), the air pollution spots, for different agriculture lands ….etc. In this mode, the area of any spot on the satellite image can be determined by finding the planimetric (Grid) coordinates (x, y) for the periphery points of the spot using ERDAS Imagine Software Programme Ver. 9.2 if the satellite image is rectified , but if it isn’t a special method is used for the rectification of the satellite image then the positions and the areas can be determined.

Evaluation of AND-CFAR and OR-CFAR Processors Under Different Clutter Models

Waleed Khalid Abd-Ali; Najim Abd-Ullah

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 964-975

In this paper an evaluation the detection performances for (AND-CFAR) and (OR-CFAR) processors under different clutter models is done for pulsed radar system.
The clutter models used in this paper are three types of distribution (Exponential Clutter distribution, Rayleigh Clutter distribution and Weibull Clutter distribution).
The two detectors (AND-CFAR and OR-CFAR) are the improved conventional Cell Average-CFAR (CA-CFAR) and Order Statistics CFAR (OS-CFAR) by making full use of the cell information. The two CFAR processors combine the results of the CA-CFAR and OS-CFAR to get a better detection performance.
The mathematical equations of the probability of detection and probability of false alarm to the two detectors (AND-CFAR and OR-CFAR) for the three clutter models are founded under the assumptions that a homogenous background with a Swerling I target, and the reference cells are Independent and Identically Distributed (IID), also the detection performances of these detectors (AND-CFAR and OR-CFAR) have been evaluated for the three clutter models first and compared between them with those of CA-CFAR and OS-CFAR for Rayleigh distribution using MATLAB-Programming (M-File).
In this paper is founded that the detection performance to AND-CFAR and OR-CFAR has not been affected by changing clutter models (clutter probability density function) for fixed probability of false alarm, also for the same probability of detection (Pd=0.7) and for fixed probability of false alarm (Pfa=10-6) and N=12, signal-to-ratio power ration (SNR) which ensure this Pd is equal (18dB) for AND-CFAR, but its equal (18.5dB) for OR-CFAR, this means AND-CFAR is better detection performance than OR-CFAR for different clutter models.

Studying the Effect of Addition of Carbon Black on Rheological Properties of Polypropylene and Polycarbonate

Najat J. Salah; Abbas A. Jawad

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 976-991

In the present research the rheological properties of polymer melt composed of (polypropylene- polycarbonate ) unfilled_ filled with different amounts of Iraqi carbon black (2 – 7) wt% was studied. Single screw extruder was used for development of these blends . The rheological behaviour of these blends was investigated by using rotational concentric type rheometer .
The rheological properties shear rate( ( , apparent viscosity (a), dynamic viscosity(ή ), shear stress (τ) and angular frequency (ω),shearing flow at various temperatures ( 220 ˚C, 240˚C and 260 ˚C) were studied and found to be increase with increasing the amount of filler and decrease with increasing temperature. The flow curves were determined in the range of shear rate from about (10 to10 2 ) s-1. The activation energy was also measured, the values of activation energy varied from(11.939 to 20.892) KJ/Mole for different formation.

Performance Evaluation of Dual Tree Complex Wavelet Packet Modulation (Dt-Cwpm) System Over Multipath Rayleigh Fading Channel

Hikmat N. Abdullah; Majid A. Alwan; Fadhil S. Hasan

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 992-1010

The effectiveness of Dual Tree Complex Wavelet Packet Modulation (DT-CWPM) with DQPSK modulation is investigated for communication over flat and frequency selective Rayleigh fading channel. The simulation results show that the performance of the proposed DT-CWPM system is better than that of Orthogonal Frequency Division Multiplexing (OFDM) and other types of Multicarrier Modulation (Slantlet based OFDM and FRAT-OFDM)for the same environment. The comparison of complementary cumulative distribution function (CCDF) of the peak to average power ratio ( PAPR) between different types of multicarrier modulation is also achieved.

The Role of Technical Growth Poles in Achieving the Dimensions of Sustainable Development of Cities (City of Basra as Model)

Sana Sati Abbas; Lubna R. Alazzawi

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 87-109

Most modern studies in the field of the city development and restructuring its physical condition are oriented toward the principals of sustainability in building up strategies for future development.
This research adapted this principal as a starting point by adapting the technical growth pole as a sustainable urban strategy.
The research goes through the available literature review, which studies this issue, analyzing many international examples in order to deduce some principals which can be applied as a long term strategic tools fit for application in Basra being a future development pole in Iraq.