ISSN: 2521-9154

Volume 20, Issue 4

Volume 20, Issue 4, Summer 2017, Page 801-1011


Simulation Study of the Variations in Driving Pressure and Frequency on Microbubbles Contras Agents Behavior.

Aladdin M. Hasson; Abdulkarim H. Dagher; Bassam T. Mohammad; Jasim A. Harbi; Furat I. Hussein; Laith A. Sabri; Ahmed Waheed Mustafa; Mays Munir Ismael; Ahmed A. Ali; Hussain Y. Mahmood; Mahmood Wael Saeed; Jumaa S. Chiad; Muhammad Safa al-Din Tahir; Shakir M. Mousa; Zaid Adnan Abdel-Rahman; Ahmed Daham Wiheeb; Marwa Majeed Jumaa; Wajdi Sadik Aboud; Dawood Eisa Sachit; Najmuldeen Yousif Mahmood; Sadiq Jafer Abbass; Duha Qais Abd-ul-Amir; Ansam M. Salman; Amal F. Jaffar; Alaa Ayyed Jabur Al-Taie; Miqdam T Chaichan; Raid Saleh Jawad; Rasha M. Hussein; Ali A-M. H. AlAsadi; Ahmed Hikmat Faseeh; Ahmed Hazim Abdulkareem; Abdul Sattar J. M.Hasan; Abdul Kadhim M. H. Hadi; Noora Saleh Ekaab; Samir Ali Amin; Sadeq Hussein Bakhy; Fouad Ali Abdullah; Dr. Abdul-Sahib T. Al-Madhhachi; Dalia Shakir Atwan; Hussain J. Al-Alkawi Electromechanical Eng. Dep; Raad M. Fenjan; Samar K. Abdul-Zahraa; Hazem I. Ali; Ali Hadi Saeed; Laith Khalid Al-Hadithy; Mustafa Mahmood Al-Ani; Fatima N. Jaseem; Mofeed A.L. Jaleel

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 801-806

The difference between the density of the gas core of microbubbles and the surrounding media causes the behavior of microbubbles contrast agents in an ultrasound field to be nonlinear and intricate. In addition, many factors affect the radial oscillations of these microbubbles. Some of these factors are related with the bubble structure and its shell material such as the initial radius of the bubble, shell thickness, viscosity of the shell material and its elasticity. Other factors are related with the incident acoustic wave such as the driving frequency and driving pressure amplitude. In this simulation study the effects of pressure and frequency as influential factors on the stability of the microbubble were studied in wide range (frequencies are extend from f

Keywords

Ultrasound contrast agents
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Microbubbles
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Bifurcation
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Nonlinear behavior
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Driving pressure and frequency

Monitoring and Control on Impressed Current Cathodic Protection for Oil Pipelines

Jasim A. Harbi; Furat I. Hussein; Laith A. Sabri

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 807-814

This research is devoted to design and implement a Supervisory Control and Data Acquisition system (SCADA) for monitoring and controlling the corrosion of a carbon steel pipe buried in soil. A smart technique equipped with a microcontroller, a collection of sensors and a communication system was applied to monitor and control the operation of an ICCP process for a carbon steel pipe. The integration of the built hardware, LabVIEW graphical programming and PC interface produces an effective SCADA system for two types of control namely: a Proportional Integral Derivative (PID) that supports a closed loop, and a traditional open loop control. Through this work, under environmental temperature of 30°C, an evaluation and comparison were done for two types of controls tested at low soil moisture (48%) and high soil moisture (80 %) to study the value of current, anode voltage, pipe to soil potential (PSP) and consumed power. The results show an decrease of 59.1% in consumed power when the moisture changes from the low to high level. It was reached that the closed loop controller PID is the best solution in terms of efficiency, reliability, fast response and power consumption

The Optimal Spacing between Finned Tubes Cooled by Free Convection Using Constructal Theory

Ahmed Waheed Mustafa; Mays Munir Ismael

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 815-822

The optimal spacing between finned tubes cooled by free convection is studied numerically. A row of isothermal finned tubes are installed in a fixed volume and the spacing between them is selected according to the constructal theory (Bejan's theory). In this theory the spacing between the tubes is chosen such that the heat transfer density is maximized. A finite volume method is employed to solve the governing equations; SIMPLE algorithm with collocated grid is utilized for coupling between velocity and pressure. The range of Rayleigh number is (103 ≤ Ra ≤ 105), the range of the tube position is (0.25 ≤  ≤ 0.75), and the working fluid is air (Pr =0.71). The results show that the optimal spacing decreases as Rayleigh number increases for all tube positions, and the maximum density of heat transfer increases as the Raleigh number increases for all tube positions and for Ra=105 the highest value of heat transfer density occurs at tube position ( =0.75) while the lowest value occurs at tube position ( =0.25). The results also show that the optimal spacing remains constant with change of the tube position at constant Rayleigh number.

Experimental and Numerical Attenuation of Vibration for Delta Wing Using PI Controller

Ahmed A. Ali; Hussain Y. Mahmood; Mahmood Wael Saeed

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 823-831

Active vibration controlling loop with proportional - Integral (PI) controller was tested numerically and experimentally for delta wing with three different manufacturing materials; aluminum, [0/90] composite and aluminum foam, both P and PI loop were tested separately. Numerical work was performed in ANSYS v.15 where controller with piezoelectric transducers was totally integrated in program macro. Experimental wings where fabricated to be tested under simulated excitation. Labview 2015 program with high speed Data acquisition were used besides actuators to perform controlling circuit experimentally. Good suppression in wing oscillation was performed where 72% of wing's time of vibration was eliminated for aluminum foam wing. Noticeable agreement was achieved between experimental and numerical responses.

A Suggested New Material to Manufacture Above-Knee Prosthetic Socket Using the Lamination of Monofilament, Cotton and Perlon Fibers

Jumaa S. Chiad; Muhammad Safa al-Din Tahir

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 832-837

At present use of glass fibers in lamination prosthetic socket, is due to its fiber strength and hardness, and low cost, but there are other more important things which must be considered than these specifications which are1the health1and safety. In this research fiberglass is replaced with monofilament fiber in order to be safe to on makers and users of this socket. In this paper two models of lamination manufacturing have been made and compared in terms of mechanical properties and fatigue life. The first is available and consists of: (4 perlon, 2 fiberglass and 4 perlon), The second is proposed lamination which consists of: (4 perlon, 1 cotton, 1 monofilament and 4 perlon). Simulations were conducted on the made socket made of two types of lamination by using ANSYS 14.5 to show the distribution of stresses, the amount of deformation and less safety factor for both cases. The results show an increase of 42% in the Young's modulus and a decrease in tensile stress and yield stress by 10.8% and 46% respectivel, As for the stress endurance it witnessed an increase of 140%.The simulation results show a decrease in the deformation by 40.7% and an increase in the minimum value of the safety factor of 0.323 to 1.05.

Improvement the Hardness of Stainless Steel 321 by Magnetic Abrasive Finishing Process

Shakir M. Mousa

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 838-845

Magnetic Abrasive Finishing (MAF) process which is a non-traditional polishing technique, is suitable for variety of engineering materials, producing high quality surfaces of parts. An experimental setup study is made to carry out MAF process to improve surface layer quality and hardness of stainless steel grade 321 plate. This study uses two different magnetic pole shapes such as conical magnetic pole without grooves and conical magnetic pole with six grooves. The finally results show that the conical magnetic pole with six grooves can create best surface layer quality and improve hardness in (MAF) process. The process parameters are the applied number of pitches between grooves, finishing time, cutting speed of magnetic pole, voltage, and volume of powder (dose). The magnetic abrasive powder consisted of silicon carbide SiC, particle size 300μm, SiC (65%), it is mixed with the ferromagnetic iron particles (iron powders), particle size 300μm, Fe (35%). Taguchi matrix L18 for five input parameters with mixed level design (2-3) levels was used for designing the experiments and optimal values evaluation for all parameters to improve the hardness. By using MINITAB software data was analyzed, the results indicate that empirical equation (mathematical predicted models) represents the relation of the input parameters with the change in micro Vickers Hardness. The most significant parameters on change in hardness are volume of powder (42.34%) and number of pitches between grooves (25.30%).

Commercial CaO Catalyzed Biodiesel Production Process

Zaid Adnan Abdel-Rahman; Ahmed Daham Wiheeb; Marwa Majeed Jumaa

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 846-852

Biodiesel produced from vegetable oils is a good alternative clean diesel. The present study was conducted because there are some variations or contradictions in literature on the use of CaO heterogeneous catalyst. In this study, biodiesel was produced from sunflower vegetable oil and methanol in presence of commercial calcium oxide catalyst in batch mechanical stirrer reactor. The effect of three operating conditions, methanol mole ratio (4-12), reaction time (0.5-2.5 h) and catalyst amount (2-10 %), on the yield of biodiesel was studied at constant reaction temperature of 60 oC. Response surface methodology (RSM) was used with central composite design (CCD) of experiments. Polynomial correlation was found for the dependent variable of the process (yield of biodiesel), satisfactorily predicted at 95% confidence level. The optimum yield biodiesel was about 98% and at operating condition of methanol ratio 10, reaction time 2 h and catalyst amount 8 %. The reaction time was found to be the most effective operating condition. Kinetics study of the process showed that first order reaction with triglyceride concentration and zero order with methanol concentration gave best fit with the experimental data, triglyceride with a reaction rate constant k= 1.53 h-1.

Adaptive Control of Robot Manipulators with Velocity Estimation and Bounded Torque

Wajdi Sadik Aboud

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 853-863

The robot manipulator output feedback problem points out to the controlled system in which the measurements of the joint position are available. In this study, all kinematic and dynamic parameters of robot manipulator are supposed unknown and the manipulator have to follow the desired trajectory. Therefore, the adaptive control problem for robot manipulators based on velocity estimation is investigated. According to the practical robot actuator power limitation, the bounded torque input is also considered in this study. The control algorithm is applied for 2-link manipulator to evaluate controller effectiveness. The design parameters that guaranteed the control performance of closed loop system are chosen by using optimization output constrained method. The proposed controller performances are provided by numerical simulations.

Effect of Several Parameters on Membrane Fouling by Using Mathematical Models of Reverse Osmosis Membrane System

Dawood Eisa Sachit

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 864-870

In this paper, models were applied to investigate the parameters that affect membrane fouling. Osmotic pressure across the membrane, salt concentration at the surface of the membrane, solute mass transfer coefficient, effective coefficient diffusion of water, and concentration polarization factor were the main parameters that calculated in this simulation. Sodium chloride was assumed the only salt existed in the feed flux. In addition, changing the applied pressure versus increasing the salt concentration in the feed flux and their effect on the water permeation coefficient was investigated. The results confirmed that concentration polarization gives a good indication about the formation of the fouling layer at the membrane surface and consequently permeate decline.

Studying the Effect of Mixture of Pomegranate Peel and Licorice on the Mechanical Properties of Epoxy

Najmuldeen Yousif Mahmood

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 871-875

Reinforcement process of epoxy has been widely used to improvement of mechanical properties. Therefore, this work is concerned with the reinforcement of epoxy by adding natural materials (Pomegranate peel and Licorice particles) at epoxy. Different percentages of particles (5, 10, 15 and 20%) were used. The mechanical testing were included tensile, bending, hardness and impact tests. Hardness of epoxy was increased at increasing of Pomegranate peel (PP) and Licorice (L) percentages. Impact resistance of epoxy with Pomegranate peel (PP) has reached the highest at (10%), while with Licorice (L) has reached the highest at (5%). The results of tensile strength represent that increases of tensile strength at all percentages of (L), while (PP) showed that decreases at (5%) and increases at others percentage. Bending strength of epoxy has increased as increasing of (PP) at all percentage that used, but it has increased at (5, 10 and 20%) of (L), while it has dropped at (15%).

Effects of Backpack Loads on Kids Posture

Sadiq Jafer Abbass; Duha Qais Abd-ul-Amir

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 876-886

Kids carrying heavy loads as a part of everyday activity may be related to bend their trunks forward to maintain body posture and balance while walking. This study was to determine a correlation between the weight of a child's backpack, their body weight, and certain features of their body posture. The study group consisted of 6 children, in age of primary school. The anthropometry (age, length, weight) were taken for each volunteers. A school backpack was specially built for the present study. Walking gait was filmed in three cases: (zero kg, 3 kg and 6 kg) backpack.
Posture was analyzed by using (Kenova and MATLAB) computer programs.
The results show that the forward inclination of the trunk increases when the load and the walking distance are increased, this forward inclination segment may impose greater stress over the vertebral column (ligaments and intervertebral disks) and increase the risk of back problems.
Spine and back health may be adversely affected by load carriage and it may be important to use spinal curvature as a measure of posture for load carriage. This study shows that the backpack load cause a lumbar asymmetry by 10 to 20 degree according to the load which has a significant amount of back pain in kids.

Studying of Laser Tissue Interaction Using Biomedical Tissue

Ansam M. Salman; Amal F. Jaffar; Alaa Ayyed Jabur Al-Taie

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 894-903

In our work, three internal regions of rat are exposed to four different lasers with different power density, and then studying the histology of the tissues. Together the total absorption and transmission of the tissues at certain wavelength were determined.
Changing the wavelength across the absorption peak caused a significant difference in laser tissue interactions and changing the absorption coefficient, relaxation time, generated heat, and the intensity as a function of penetration depth. Furthermore, little mechanical damage could be seen in conventional histology.

The Influence of Graphene Oxide Addition on The Fortified Nitrile Butadiene Rubber Nano-composite Qualities

Miqdam T Chaichan; Raid Saleh Jawad; Rasha M. Hussein

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 904-910

Strengthening elastomers by the Nano-fillers, for example, Graphite subordinates, have high embellishments on their attributes. In the present work, Graphene Oxide (GO) nano-sheets have scattered in huge rubbers was Nitrile Butadiene Rubber (NBR). Enhancement the vulcanization procedure on (GO/NBR) nano-composite elastic was performed by arrangement blending strategy and rumination blending method. Scattering of GO into NBR was homogenous, where affirmed by Scanning Electron Microscopy (SEM) and X-beam Diffraction (XRD) test. Breaking down the useful gatherings by Fourier-Transformed Infrared Spectrophotometry (FTIR) has been explored as well. Diverse stacking wt% of GO inside NBR has clear impacts on the rigidity and flexibility conduct of the nano-composite. Impact of GO on the electrical conductivity and persuasive properties of GO/NBR nano-composite elastic portrayed too. The GO presence has upgraded the crosslinking trademark in GO/NBR nano-composite elastic and enhanced its properties.

Fluidics Jet Vectoring for Incompressible Flow by Using Counter Flow Method for Circular Duct

Ali A-M. H. AlAsadi; Ahmed Hikmat Faseeh

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 911-923

Computational and experimental investigation of fluidic thrust vectoring using counter-flow method had been carried out in the present work. The experimental investigation involved the design and construction of a test rig for a circular duct to examine the effect of various geometric variables on the thrust vectoring angle. The experimental tests covered Coanda surface radius R/d = (0.58823, 1.17647, 1.75471), secondary gap height h/d = (0.02941, 0.05882), over a secondary mass flow ratio range (0 ≤ m ̇S/m ̇p ≤ 0.06568). Load cell readings were obtained using two components overhead. The computational investigation involved a 3D numerical solution using ANSYS Fluent. The test cases parameters used in the experimental work were used as an input for the numerical solution. The results show that the thrust vectoring angle is increased by increasing the secondary suction rate. Three control zones can be observed: a “dead zone” can be seen at low mass flow ratios. Followed by a control region where continuous primary jet control is achievable until a saturation region is reached. The coanda surface ratio determines the length of the dead zone in which small coanda surface resulted in an extended dead zone region. The secondary gap height increase had an inverse effect on the thrust vectoring angle. The investigation shows that both experimental and computational results obtained followed a similar general pattern and gave a good agreement when compared with available studies on jet vectoring angle.

Development Models of Artificial Neural Network and Multiple Linear Regression for Predicting Compression Index and Compression Ratio for Soil Compressibility of Ramadi City

Ahmed Hazim Abdulkareem

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 924-936

Artificial neural networks (ANN) as new techniques employed for the development of predictive models to estimate the needed parameters in geotechnical engineering to be used for comparison with laboratory and field tests and consequently reduce the cost, time, and effort. Flexible computing techniques are using an alternative statistical tool to analyze and evaluate experimental data from 102 consolidation tests on a variety of undisturbed soils from Ramadi city. The regression equations are developed to estimate the compression index and the compression ratio from index data. Multi-Layer Perceptron (MLP) network model is used to calculate compression index and a compression ratio of soils and comparing with the multiple linear regression statistical model MLR. It is found that the MLP showed a higher performance than MLR in predicting Cc and Cr and model accuracy between 0.81 to 16 percent. This will provide a good method for minimizing the potential inconsistency of correlations.

The Effect of Using Castor Oil on the Pollutants Emission in a Continuous Combustion Chamber

Abdul Sattar J. M.Hasan; Abdul Kadhim M. H. Hadi; Noora Saleh Ekaab

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 937-944

This study investigates the effect of Castor oil on the pollutants emissions in the continuous combustion chamber. The bio-blend fuels used are mixtures of Castor oil with two types of hydrocarbon fuels (gas oil and kerosene). The pollutants measured include carbon monoxide CO, unburned hydrocarbon UHC, soot and nitrogen oxide NOx . It is found that all pollutants have less emissions when using Castor oil blended in different percentages of 5% , 7%, and 10% . The lower emission with Castor oil blends due to the existence of oxygen O2 in the chemical structure of the Castor oil which is sufficient to seek the complete combustion. The test were conducted through the range of equivalence ratio between (0.85-1.7) . Results showed that Castor oil blends with gas oil brings a reduction of about 71.2% in CO, 22.1% in UHC, 37.8% in NOx and 29.6% in soot emissions from that of pure gas oil. But, blends with kerosene, showed a reduction of about 70.6% in CO, 20% in UHC, 35.8% in NOx and 29% in soot emissions compared with those of pure kerosene.

Study the Effect of Welding Parameters on the Residual Stresses Induced by Submerged Arc Welding process

Samir Ali Amin; Sadeq Hussein Bakhy; Fouad Ali Abdullah

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 945-951

Welding residual stress has influences on fatigue, fracture, and corrosion. It is therefore important to explore the welding factors effect on the residual stresses. In this work, four welding factors (current, arc voltage, welding travel speed and included angle) were used to weld low carbon steel (ASTM A516 Grade 60).The experiments included welding of (60) pieces with dimensions of (300 x 150) mm and 10 mm thickness that were conducted based on the design matrix founded by using design of experiment (DOE) software (DESIGN EXPERT 10) with response surface methodology (RSM) technique. The X-Ray diffraction (XRD) method was used to measure the residual stress, which was then modeled and optimized in terms of the welding factors using (RSM) technique. The data showed that the welding travel speed and arc voltage have a significant influence on the residual stress. It was found that the optimum solution for minimum residual stress was at 450 Amp welding current, 34 volt arc voltage, 38 cpm welding speed, and 60⁰ included angle. Where, the optimum value of residual stress was (-88.4 MPa). Finally, the predicted and experimental results of residual stress were in agreement with a maximum error of 1.8%.

Variability in Soil Erodibility Parameters of Tigris Riverbanks Using Linear and Non-Linear Models

Dr. Abdul-Sahib T. Al-Madhhachi

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 959-969

Most researches have predicted soil erosion of cohesive riverbanks using linear (excess shear stress model) and non-linear (Wilson model) models based on two soil parameters (detachment coefficient, kd, and critical shear stress, τc) of the linear model and two soil mechanistic parameters (mechanistic detachment parameter, b0, and threshold parameter, b1) of the non-linear model. The goal of this research was to quantify the soil erodibility parameters of Tigris Riverbanks on Nu’maniyah-Kut Barrage reach using linear and non-linear models through the model parameters at three different water contents: dry side, optimum side, and wet side of water contents. Soil samples were collected from three locations south of Baghdad city on Nu’maniyah-Kut Barrage reach of Tigris Riverbanks. Six soil samples acquired from these sites were laboratory tests achieved using a miniature version of Jet Erosion Test device (“mini” JET) to determine the erodibility parameters of both linear and non-linear models. Blaisdell solution (BL) and scour depth solution (SD) were applied to determine (kd and τc) of linear model from JETs data. Physical soil characteristics; including bulk density, particle size distribution (sand%, silt%, and clay%), average particle size (D50), and angle of repose were reported for six samples acquired from the three sites. The results showed lower value of kd of toe in compared with bank side for some specific sites as observed for both BL and SD solutions of excess shear stress model especially at wet side of water content. No general pattern of τc related to different water content were observed. The parameters (b0 and b1) of non-linear model have the same behavior of linear model parameters (kd and τc), but with different magnitude related to different water contents, respectively.

Effect of Particle Size of Waste Glass on Compressive Strength and Modulus of Rupture of Concrete Mix

Dalia Shakir Atwan

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 970-975

Glass is an inert material which could be used and recycled many times. Several tons of waste glass (WG) are generated annually worldwide due to the rapid growth of the population and improvement in the standard of living. In this study, the WG was used and supplied with three different particle sizes; 600µm, 2.36 mm and 4.75mm and partially weight replaced of fine aggregate at ratios 10%, 20% and 30%. The effectiveness of that changes on compressive strength and modulus of rupture at ages 28 and 90 days for concrete specimens produced were studied. The results showed that compressive and modulus of rupture at all ages increased along with addition of WG as glass powder (GP). Moreover, the specimens containing 30% of GP replaced has the best results, also it is found at this percentage of GP, more beneficial and capable to increased compressive and flexural strength up to 18.64% and 5.87 % respectively at 28-day compared to reference specimen. Besides, the test results revealed that at a replacement level 10% of 2.36mm fine glass (FG) has slightly improved the strength characteristics. While, the results demonstrated decreasing in that properties for the concrete specimens contained on coarse glass (CG) up to 4.75mm. The maximum negative effect on compressive strength and modulus of rupture recorded at the ratio 30% of CG where was the reduction in compressive strength 28.52% opposite 22.12% for modulus of rupture at age of 28-day. From that results, it can be concluded that the effect of FG was little compared to GP.

Thermo-Mechanical Fatigue (TMF) Model for (2017-T4) Aluminum Alloy under Variable Temperature

Hussain J. Al-Alkawi Electromechanical Eng. Dep; Raad M. Fenjan; Samar K. Abdul-Zahraa

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 976-982

In this work, constant and increasing temperature fatigue interaction effect on fatigue behavior of 2017-T4 aluminum alloy was investigated. Fatigue tests at constant load constant temperature and constant load increasing temperature were performed for five applied stresses which are (350,275,200,175 and 150 MPa) that based on the tensile test behavior .The constant temperatures were room temperature (RT) (25 ̊C) and 100 ̊C. While the increasing temperatures were RT, 50 ̊C, 100 ̊C and 150 ̊C for one test program. The constant fatigue property of the increasing temperatures was observed the worst case compared to the others constant fatigue properties. A new variable temperature fatigue damage model was proposed. It is based on the S-N curve and taking into account the effects of constant loads and variable temperature. A comparison between prediction of the proposed model and crack growth rate due to Miner rule was made. The results proved that this model is satisfactory and gave safe results than Miner rule compared to experimental data.

Robust Tuning of PI-PD Controller for Antilock Braking System

Hazem I. Ali; Ali Hadi Saeed

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 983-995

This paper presents the design of robust four parameters (two degree of freedom) PI-PD controller based on Kharitonov theorem for antilock braking system. The Particle Swarm Optimization (PSO) method is used to tune the parameters of the proposed controller based on Kharitonov theorem to achieve the robustness over a wide range of system parameters change. The proposed cost function combines the time response specifications represented by the model reference and the frequency response specifications represented by gain margin and phase margin and the control signal specifications. The model reference control is used because of the antilock braking system is originally nonlinear and has different operating points. The robust stability is guaranteed by applying the Kharitonov theorem. Three types of road conditions (dry asphalt, gravel and icy) are used to test the proposed controller.

Nonlinear Finite Element Analysis of RC Beams without Stirrups Strengthened by Longitudinal Soffit Bonded CFRP Strips for Shear

Laith Khalid Al-Hadithy; Mustafa Mahmood Al-Ani

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 996-1004

This study concerns utilization of nonlinear finite element method for to evaluate the role of longitudinal soffit-bonded CFRP strips in elevating the shear behavior of RC beams without stirrups. All beams cross-sections were of 150 mm breadth and 200 mm depth, the overall length was 1500 mm with clear span 1300 mm. One beam was provided by minimum web reinforcement according to the ACI 318M-14, while the other five were without web reinforcement but externally strengthened by a variety of CFRP-strip combinations consisting of longitudinal soffit-bonded strips. The predictions of a proposed ANSYS (version 14.5) model for six of the test beams including modeling of concrete, steel rebars, CFRP strips and supports and loading steel plates, by SOLID65, LINK180, SHELL41 and SOLID185 elements, respectively, show high agreements with experimental evidence, which stands as a definite witness to the efficiency and reliability of the present numerical model.

Study the Effect of Electrodeposition Parameters on Ni/SiC Composite Coating

Fatima N. Jaseem; Mofeed A.L. Jaleel

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES, Volume 20, Issue 4, Pages 1005-1011

In this research, we successfully obtained Ni/SiC micro-composite coatings with various contents of SiC particles of particle size(10 µm), by using electrodeposition method from nickel watts bath in which the SiC particles suspend. The effects of the current density, temperature, and particle loading(PL) of SiC particles in the electrolyte on the morphology, texture, and vol% of SiC in deposit were investigated. The morphological and structural analysis show uniform distribution of SiC particles within the composite coatings. It was found that the depositing conditions affect the microstructure of deposited nickel and the SiC vol% in deposit. Furthermore, the vol% of SiC increases in deposit by increasing the particle loading(PL) in the bath, while decreased by increasing the current density. Also the higher values of SiC vol% were obtained at temperature (50°C).