Table of content

ALNAHRAIN JOURNAL FOR ENGINEERING SCIENCES

مجلة النهرين للعلوم الهندسية

ISSN: 25219154 / eISSN 25219162
Publisher: Al-Nahrain University
Faculty: Engineering
Language: Arabic and English

This journal is Open Access

About

AlNhrain Journal for Engineering Sciences is a refereed scientific engineering journal published by the College of Engineering, Nahrain University two times per year. The journal publishes the scientific output of researchers from Iraq and abroad in the fields of architectural, chemical, civil, computer, electrical, information technology, laser and optoelectronics, mechanical and medical engineering as well as in related fields. Papers written in Arabic and English are accepted and they are subjected to proper evaluation and accordingly classified as follows:
• Original research papers and papers on novel design, analysis or construction methods of great value to the engineers which include basic and practical results.
• Short communications or short discussions on papers which have already appeared in the journal provided that whose text should not exceed 800 words.

The material of the paper should not violate any intellectual property right of any person or entity and should not contain any subject matter that contravenes any laws and should meet ethical standards applicable to the research discipline.

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Contact info

Editor-in-Chief
College of Engineering Journal
Al-Nahrain University
P.O. Box 64040 , Al-Jadyriah
Baghdad-Iraq.
e-mail: journal.engineering@nahrain-eng.org
jourengnah@gmail.com
Phone: +964 (0) 7817 202 662

Table of content: 2017 volume:20 issue:3

Article
Effect of Medium Quenching and Temperature on Corrosion Behavior of Aluminum Alloy 6061

Authors: Abbad Kassouha --- Sami Entakly
Pages: 498-504
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Abstract

In the present work the effect of heat treatment processes at different temperatures and in different quenching media on mechanical properties in addition to corrosion behavior in different pH solutions of aluminum alloy 6061 was achieved. The alloy was received as fabricated and the solution heat treatment processes was achieved at temperatures (490,530,570 °C), then quenching for every degree was done in two media (water, oil) to obtain on six samples. The artificial aging was done on every sample at temperature (160°C) for one hour. The microstructure was examined to show Mg2Si in every sample. The results of hardness test showed that the hardness of alloy increased with increasing heat treatment temperatures, and at the same temperature the quenched specimens in oil had higher hardness. On the other hand, the tension tests showed that the strength of alloy increased with increasing of heat treatment temperature, and at the same temperature the quenched specimens in water had higher hardness. The results of corrosions test showed that the heat treatment operations improved corrosion resistance, and the lower value was get upon treating at 530°C.


Article
Effect of Heat Treatment on The Hydroformability of CuZn 35 Sheet Metal

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Abstract

Sheet metal forming becomes a research topic for its widely using in the industrial field, these researches seeking for a better specifications of the products with low cost of production processes using available raw materials. In this work the sheet metal used is CuZn35 1mm thick. This sheet metal formed by a process named hydroforming process using a square shaped die to form the sheet metal according to its cavity by the pressure of the hydraulic which must be in direct contact with the surface of the sheet metal. Tests had been made for this sheet metal and for the final product for the as received specimen and for the heat treated one which shows the improvement of the formability of this sheet metal.

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Article
Effect of Temperature on Buckling of Composite Materials Column

Authors: Kadhim K. Resan --- Mohammed H. Ali --- Noor K. Faheed
Pages: 511-519
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Abstract

A theoretical and experimental investigation pertaining to the buckling behavior of slender fiber reinforced polymer columns subjected to axial loading under varying temperatures (from room temperature to 50℃). Two groups of composite materials were used for manufacturing of test specimens, the first consist of perlon fiber as a reinforcement and acrylic resin as a bonding matrix, while the second consists of a combination of perlon and carbon fibers as reinforcement. The composite specimens were fabricated by vacuum molding technique and cut according to ASTM D-638 for conducting tensile test. The data from tensile test were used to calculate the effective slenderness ratio and defining the column as Euler buckling column. An experimental rig was designed, manufactured and calibrated to study the effect of thermal and buckling load subjected to columns. Numerical analyses pertaining the buckling behavior for both groups were conducted. The results show that the temperature has a considerable effect on properties of fiber reinforced polymer composites where the value of critical load and Young's Modules decrease with the increase of temperature for both groups. Perlon & Carbon reinforcement composites gave best mechanical properties, which make them the best candidate to improve the buckling resistance characteristics of composite materials.


Article
Study The Effect of Conditions of The Electro Spinning Cabin (Humidity) on Electro-spun PolyVinyl Alcohol (PVA) Nano-fibers

Authors: Samara Alswid --- Manal Issa
Pages: 520-525
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Electrospinning is a simple and highly versatile method for generating ultrathin fibers (mainly polymers) with diameters ranging from a few micrometres to tens of nanometres. This technique has attracted tremendous recent interest in both academia and industry, owing to its unique ability to produce ultrafine fibers of different materials in various fibrous assemblies. Electrospinning is a process that uses an electric potential to overcome the surface tension of a solution to produce an ultra-fine jet, which elongates, thins and solidifies as it travels through the electric field to a collector.. In this research, we studied the effect of conditions of the cabin “specifically humidity” on the diameter of nanofibers manufactured by electrospinning. We used Polyvinyl alcohol (PVA) polymeric solution with weight concentration of 10%, voltage 20 kv, under different values of relative humidity. Fiber morphology and fiber diameter were determined using scanning electron microscope, and measuring the fiber diameter by using image j program. It was found that the diameter of the fibers increased with increasing the relative humidity within our studying area .


Article
Thermohydrodynamic Characteristics of Worn Journal Bearing Lubricated With Oil Containing Nanoparticles Additive

Authors: Basim A. Abass --- Nadhim F. Mohammed
Pages: 526-543
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In the present work the worn journal bearing is simulated to discuss the effect of adding TiO2 nanoparticles to the base oil on its thermal performance. An extensive numerical investigation is carried out to study the effect of different parameters affecting thermal performance of worn journal bearing such as the eccentricity ratio (ε), the wear depth parameter (δ), and the nanoparticle concentration (Φ). The computational approach is provided by using finite difference method for solving the governing equations, namely, the modified Reynolds equation, energy and heat conduction equations with suitable equation to include the variation of the oil film thickness due to the bearing wear in order to estimate the benefits of using nanolubricant in worn journal bearings. Oil viscosity dependence on nanoparticle concentrations is considered by using Krieger Dougherty model. The mathematical model as well as the computer program prepared to solve the governing equations were validated by comparing the oil film pressure distribution obtained in the present work for a worn journal bearing with that obtained numerically by Hashimoto et.al [2](1986) with 3% maximum deviation between the results. The maximum oil film pressure obtained in this work was compared with that obtained experimentally by Roy [12] (2009) for intact journal bearing with 3% as a maximum error between the results. The results obtained show that the nanoparticles addition by 0.5% and 1% to the base oil increases the load carrying capacity of the worn journal bearing by 20% and 40% respectively while decreases the oil side leakage by 5% and 10% and friction coefficient by 2.75% and 5.7% as compared to that lubricated with pure oil. This is happen with the expense of power losses. Calculations also shows that adding a higher percentage of nanoparticles (2%) has a harmful effect on the performance of a worn journal bearing since the power losses is highly increased.


Article
Application of ANFIS for Prediction Micro Holes in EDM

Authors: Shukry H. Aghdeab --- Raed R. Shwaish
Pages: 544-549
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The present work demonstrates the optimization process of Micro- hole of Electrical Discharge Machining (EDM) by Adaptive Neuro Fuzzy Inference System (ANFIS). The workpiece material was copper alloy. The current, gap distance and pulse on time were the control parameters of EDM. The process has been successfully modeled using ANFIS model constructs a fuzzy inference system in MATLAB 7.2 Software Gaussian type for optimization of micro diameter, were adopted during the training and testing process of ANFIS model in order to compare the prediction accuracy of micro diameter by one membership function. Finally, the comparison of ANFIS results with experimental data indicates that adoption of Gaussian membership function in proposed system achieved satisfactory accuracy. Prediction using ANFIS model compared with experimental values of micro holes at correspond ratio 98.37%.

Keywords

EDM --- ANFIS


Article
Optimal Policies for Conjunctive-Use and Cropping Pattern for Al-Wand Basin

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Applying conjunctive use between surface water and ground water is getting widely used at many regions in the world, due to the increasing need of water resources, especially when large quantities of water and for long time are used for irrigation purposes to meet agricultural production requirements. The linear programming has been formulated to optimize the optimum allocation of water. An economic analysis of conjunctive use for Al-Wand project in Iraq has been done for a certain cropping pattern using two scenarios of management and operation of ground water and surface water. One suggested scenario was to use ground tank to save the water during the period of water excess to be used during the shortage period. The other scenario was to operate the reservoir dam to supply the water requirements during the agriculture years. The main concerns of this research were: the fluctuation of the ground water and how to estimate the deficit of yield which is caused by using the decreased water in irrigation. The economic analysis has been done by calculating the overall cost and the annual estimation of return. It can be concluded that the operation of surface water at (60 and 70%) from total available surface is a compromise, because some of the water still flow in the river and canals and the ground water reservoirs were not affected especially its storage capacity.


Article
Robust Controller Design for Two Wheeled Inverted Pendulum System

Authors: Hazem I. Ali --- Zain AlAbdeen M. Shareef
Pages: 562-569
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In this paper, the design of a robust controller for two wheeled inverted pendulum (TWIP) system is presented. In the first stage of the design, a full state feedback H_2 control is designed for stabilizing the inclination of (TWIP) system to upright position. The 〖 H〗_∞ controller for the stabilized system is synthesized in the second stage. The mathematical model of the system based on the Newtonian approach is developed. The results verify that the proposed controller can compensate the system parameter uncertainty with a more desirable time response specifications.


Article
Robust Controller Design for Two Wheeled Inverted Pendulum System

Authors: Hazem I. Ali --- Zain AlAbdeen M. Shareef
Pages: 562-569
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In this paper, the design of a robust controller for two wheeled inverted pendulum (TWIP) system is presented. In the first stage of the design, a full state feedback H_2 control is designed for stabilizing the inclination of (TWIP) system to upright position. The 〖 H〗_∞ controller for the stabilized system is synthesized in the second stage. The mathematical model of the system based on the Newtonian approach is developed. The results verify that the proposed controller can compensate the system parameter uncertainty with a more desirable time response specifications.


Article
Application of HEC-RAS Model to Predict Sediment Transport for Euphrates River from Haditha to Heet 2016

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The aim of this study is to evaluate the sediment transport and to assess the quality of water for a reach of Euphrates River with a length of (124.4 km), begins from downstream of Haditha dam which represents the upstream of study, and ends at Heet station in Heet city which represents the downstream. There are 196 cross-sections which were distributed along the study area by using the model of one-dimensional HEC-RAS version 4.1. Calibration and Verification processes from(01-Sep-2013) to (30-Nov2013) and (01-DEC-2013) to (28-FEB-2014) respectively, show that the optimal Manning Roughness Coefficient (n) is equal to (0.033) which gives the less error ratio between the observed and calculated water surface elevations. By comparing the results of sediment transport “mass accumulated” for this study which equal to (237.38ton/day) was larger than the value of the previous study which equal to (165ton/day, measured in 2010). But the value of sediment load of this study at Heet station was equal to (551.76 ton/day) which was less than the value of previous study (189.041×〖10〗^3 ton/day, measured in 1988), due to increasing in the rates of discharge that was arrived the reach of study area.


Article
Preparation and Characterization of Copper Nanocomposite Catalysts and its Activity for Adsorption of Lead from Aqueous Solution

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Abstract

The efficiency of adsorption using copper nanocomposite catalysts for the removal of lead ions from aqueous solution was studied. Nano copper and its nanocomposition were prepared in laboratory in very accurate conditions. After preparing samples, the samples were analyzed using XRD and SEM and that shows very good morphology of catalytic performance and has nano sized of crystalline shape. In order to study the efficiency of these catalysts, all samples were tested using adsorption process. The preparing samples show very good efficiency for lead removing from aqueous solution, and reach maximum removal efficiency 96% for 0.05g of adsorbents at pH 10, otherwise increasing or decreasing the pH would give undesirable results for all samples. Langmuir isotherm fitted better than Freundlich isotherm for adsorption of lead.

Keywords

Nanocomposits --- Adsorption --- Lead


Article
Experimental and Numerical Study the Influence of Sheet Metal Thickness on a Deep Forming Operation of Multi Stages for Hexagonal Cup

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Abstract

In this research, experimental and analytical deep drawing of the several-stages design mold is produce hexagonal cup and also proved the influence of the thickness of the sheet on the allocation of strain and laminating in curvature of the cup area for all stages of the drawing. Three stages deep drawing mold was designed and constructed to carry out the experimental work required to produce a hexagonal cup of (28.25 mm by 24.5 mm) , (60 mm) high drawn from a circular flat sheet (80 mm diameter), made from low carbon steel (1006–AISI). Analysis program (ANSYS11.0) to perform the finite element method to accomplish the analytical side of the search. Three types of thickness sheet (t_° = 0.5, 0.7,1 mm) with constant radius of curvature of punch equal to (R_p =4) mm, radius of curvature of die equal to (R_d =8 mm) and radius of curvature of wall of die (R_c= 4 mm) were used. From the experimental and analytical results of the three stages of drawing, it has been found that drawing load less than the more advanced stages of drawing operation on the wall of cup, maximum laminating take place at curvature of the cup area with sheet thickness equal to (t_° =0.5 mm) and maximum thickening take place at the at throat cup with sheet thickness equal to (t_° =1 mm), the maximum values of strains (radial, hoop, thickness and effective) take place at throat cup with sheet thickness equal to (t_° =1 mm).


Article
Design of SCADA System for Oil Pipeline Control Using LabVIEW

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The paper describes a design and simulation of a Supervisory Control And Data Acquisition (SCADA) system to control oil pipeline and depot plant. The aim of the process is to control oil transportation through a shared pipeline and to minimize products contamination. The study attempts to fulfill an optimal sequence of batches of refined products to satisfy the customer demands in term of: volume , maximum flow rate, optimizing the total operational cost, and reducing products contamination. The proposed system introduces a control algorithm to perform process control system functions and for achieving the tasks and actions in specific sequences and precedence. The control algorithm performs processing of pumping station control, sharing single oil pipeline, maintaining tanks level, and depot inventory control. This paper investigate many factors which effects the length of transmix segment, which enable to offer optimum solutions to reduce products contamination. LabVIEW software is used for performing various signals acquisition and monitoring, also for simulating and designing the control system strategy.


Article
The Influence of Fines Content on the Mechanical Properties of Aggregate Subbase Course Material for Highway Construction using Repeated Load CBR Test

Authors: Adil N. Abid --- Abdulhakim O. Salih --- Esraa A. Nawaf
Pages: 615-624
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Abstract

The effect of fines content (material finer than 0.075 mm) on the mechanical properties of subbase course aggregate is studied in this paper. a laboratory tests were carried out using percentage of fines material 5%, 10% and 15% by weight adding to the original subbase aggregate class B according to Iraqi specification (SCRB) which the specification limit the range of fines between 5-15%. The repeated load CBR test was done to study the mechanical properties; accumulative permanent, elastic deformation and equivalent elastic modulus. The RL CBR test was useful technique to assess the influence of fines material and stress level on the equivalent elastic modulus, and on the evolution of deformation. The equivalent modulus increase when adding 5% of fines material in case of plastic fines, but in case of non-plastic the increase continues until adding 10% fines material. Adding fines material also led to change in accumulative permanent deformation, where adding 5% fines material increase the permanent deformation by 36%, 5% for material with plastic fines and 20% for material with non-plastic fines for unsoaked samples. In case of soaked samples permanent deformation increase by 28% and 25% at adding fines material for material with plastic fines where decrease by 1% at adding 5% fines to original granular material with non-plastic fines. The theoretical modeling show that the deformation increase by increasing number of loads repetitions.


Article
Strengthening and Retrofitting of Reinforced Concrete Hollow Columns using High Strength Ferrocement Fibers Composites

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Eight RC circular hollow columns (external diameter = 220 mm, internal diameter = 100 mm, length = 1000 mm and the hollow part = 700mm) casted and strengthened with ferrocement fibers composites to illustrate the behavior of these columns under concentric and eccentric axial compression force. Two columns where used as reference columns, which were repaired after failure to be tested as retrofitted columns. Six specimens were strengthened with one and two WWM layers as required. The variables considered included number of the WWM layers (N), the loading configuration and the eccentricity value (e) of loading. The ferrocement thickness was constant at 20 mm in all retrofitted and strengthened specimens. The test results revealed that the maximum increase in the ultimate concentric loads were 67% by strengthening the reference column with two layers of WWM, and the maximum increase in the ultimate eccentric load of columns was 78% by increasing of the WWM from one to two layers. For a constant number of WWM layers, the change from concentric to eccentric force caused a decrease in the ultimate load value attaining 73.5% for one- layer WWM strengthened columns. The failure of columns occurred by yielding of steel reinforcement followed by concrete crushing (i.e. tension failure).


Article
Fiber Bragg Grating in Biomedical Application

Authors: Arwa A. Moosa
Pages: 636-640
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The aim of this work is to use Fiber Bragg Grating (FBG) to detect the breast cancer at its earliest stages based on the Photoacoustic (PA) hybrid technique. The fiber Bragg gratings sensitivity to acoustic wave, effect of grating length, effect of grating refractive index modification, and ultrasonic frequency on the wavelength sensitivity and intensity sensitivity of the ultrasonic sensor (FBG) for ultrasonic waves were investigated using a simulation programs. A wavelength for the photoacoustic (PA) excitation laser was chosen with respect to a high absorption by the tumor and with low absorption to the surrounding tissue (normal tissue); for higher contrast absorption between them. Fiber Bragg can be used as a sensor to detect the acoustic wave emitted from the tumor (depending on the photoacoustic principle). In this study, k-wave a MATLAB toolbox was used to simulate photoacoustic wave which is detected with fiber Bragg grating simulation, using Optisystem program. The acoustic wave was transferred to FBG by using Optisystem-MTLAB communication programs to detect tumors.


Article
Significance of using a Superpave Gyratory Compactor to Simulate Field Compaction of Fine Grained Soil

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Field compaction equipment used for fine grained soil usually applies a kneading action or vibration that produces shear forces which also reshape soil particles arrangement. A state that might not be completely simulated by laboratory Proctor tests. This study aims at investigating the significance of using the newer modified Texas superpave gyratory compactor (SGC) to simulate field compaction of fine grained soil due to its ability to apply loads in different angles generating shear forces on the compacted soil specimens. Two types of soil (A-4) and (A-7-6) were compacted using standard Proctor, modified Proctor and (SGC). The results were compared to dry field densities of the same soil in order to evaluate the most representative test. It was found that maximum dry densities of soil type (A-4) obtained using (SGC) under (200 kPa) and (600 kPa) were lower by (2.07%) and higher by (1.35%) than the maximum dry densities obtained using standard and modified Proctor tests respectively. It was also found that maximum dry densities of soil type (A-7-6) obtained using (SGC) under (300 kPa) and (600 kPa) were lower by (1.02%) and higher by (1.23%) than the maximum dry densities obtained using standard and modified Proctor tests respectively. The aforementioned confinement pressure values were applied in order to achieve dry densities similar to that obtained by Proctor tests. When comparing laboratory results to dry filed densities, it was found that (SGC) test results were slightly closer to them than Proctor tests results. Nevertheless, the difference between (SGC) and Proctor tests results seems to be insignificant for these types of soil compared to the higher effort needed to perform (SGC) tests.


Article
Optimization of Process Parameters for Bioethanol Production from Low grade Iraqi Dates

Authors: Hussain Majeed Flayeh
Pages: 647-656
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Box-Wilson experimental design method was employed to optimize bioethanol production from low grade, unclassified, waste Iraqi dates. The optimization process was based on four independent relevant parameters-initial sugar concentration (50-100 g/l), pH (4.5-6.5), fermentation time (48-96 hrs), and temperature (25-35℃). A maximum bioethanol yield of 33.9 g/l was practically achieved following thirty different experimental runs, as specified by 24-Central Composite Design (CCD). The optimum values for the aforementioned four parameters, corresponding to the maximum yield, were: 75g/l, pH 5.5, 72 hrs, 30℃, respectively. The obtained experimental data were utilized to develop a semi-empirical model, based on a second-degree polynomial, to predict bioethanol yield. The model was tested using ANOVA software (Design expert® 9) and found acceptable (R2=0.9025). Yield response surface and contour plots were created using the developed model, which revealed the presence of high-yield plateaus whose specifications will be useful in controlling pilot-or industrial scale future units to ensure economical feasibility.


Article
A Comparative Study of the Performance of Finned Tube Air Cooled Condenser with Refrigerants R22 and R407C

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Mathematical and numerical study of finned tube air cooled condenser for air conditioning unit with two ton refrigeration capacity using R22 as a base fluid and R407C an alternative fluid was investigated. Different parameters were considered in this work, such as condensing pressure, ambient temperature and refrigerant mass flow. A comparison of performance between two condensers when using R22 and R407C were performed. A redesign the condenser operates with the R407C to operate with the same system that operates with R22. The result showed the same behavior for the two refrigerants, the condensers are possible to work with R407C for the same geometry and some modifications in the structure of heat exchange with the same air velocity. The proposed model was validated with the outputs from the test data given in literature papers, derived from air cooled condensers with different dimensions. The results exhibited an agreement with the experimental results with a percentage of compatibility ± 10%.


Article
Determination of Mass Transfer Coefficient for Copper Electrodeposition by Limiting Current Technique.

Authors: Marwa H. Ibrahim --- Sarmad T. Najim
Pages: 666-672
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An experimental study was conducted to investigate the mass transport behavior for electrochemical reduction of copper in the presence of 0.5M H2SO4 as supporting electrolyte by limiting current technique (LCT). The experiments were carried out via rotating cylinder electrode made of copper as cathode. The effects of various operating conditions: rotation rates 100, 200, 300, 400, and 500rpm, electrolyte temperatures 30, 45, and 60℃, and cupric ions concentration 250, 500, and 750 ppm on mass transfer rate were studied. It was observed that mass transfer coefficient based mainly on rotation rates, then temperature and finally cupric ions concentration. The electrodeposition of cupric ions was proved to be a mass control. The mass transfer coefficient for rotating cylinder electrode was correlated with the aid of dimensionless groups as follows: Sh = 0.236 Re^(0.664 ) Sc^0.356 And the above correlation is a good agreement with eisenberg equation.


Article
Single and Binary Biosorption isotherms of Different Heavy Metal Ions Using Fungal Waste Biomass

Authors: Hasanain Saad Al-Hares
Pages: 673-684
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The ability of fungal waste biomass type White Agaricus Bisporus to biosorb Pb(II) ,Cr(III), Cd(II) and Co(II) from wastewater was investigated in batch process. Single and binary mixtures were used at low metal concentration wastewater treatment. The size of the biosorbent ranged 0.3-1 mm. The biosorption capacity of the biosorbent was evaluated under equilibrium conditions at 25 °C. Results indicated that the biosorption capacity of waste of fungi for the binary mixture was always lower than that for a single component system. Eight isotherm models were used to fit the experimental data of single system and Langmuir model was found a suitable to describe the biosorption data. The maximum uptake capacity (qe) of Pb(II), Cr(III), Cd(II) and Co(II) in single system was 158.73, 46.94, 40.16 and15.94 mg/g respectively with correlation coefficients 0.999,0.998,0.988 and 0.991 respectively. For binary system, four biosorption models were used to fit the experimental data. Extended Langmuir model gave the best fitting. The removal percentage of heavy metals onto fungal waste biomass was in order of Pb(II) > Cr(III) > Cd(II) > Co(II) in both single and binary system. The results show that the using waste of fungi as a biosorbent of heavy metals gave a higher uptake capacity of four heavy metals.


Article
Design of Integral Sliding Mode Controller for Servo DC Motor

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DC servo motor is simple in construction and control and has many applications. However, the uncertainties due to its parameters changes such as load torque and friction are an evitable. Therefore, a robust controller has to be employed for keeping specified requirements irrespective to parameter variations. In the present work, two sliding mode controllers have been suggested to control the speed of DC motor under motor load changes; classical and integral sliding mode controllers. The integral slide mode control could show better tracking characteristics than its counterpart and also could compensate the change in system parameters.


Article
An Investigation to the Performance of Quantized DSSS in Mobile Wireless Communications under AWGN and Multipath Fading Channels

Authors: Dr. Riyadh Jabbar Soudani
Pages: 692-700
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This paper presents an investigation to the performance of quantized direct-sequence spread spectrum system (DSSS) in mobile wireless communications systems. To obtain a real world value (RWV), the DSSS received signal is quantized to different levels of fixed-point values. These modes of quantization are evaluated by calculating BER under different channels environments (AWGN, Rayleigh, and Rician multipath fading). The effect of range of the represented values, the number precision and increasing in quantization noise on the performance of quantized DS in mobile wireless communications is also investigated. Based on simulation results, it is observed that quantized direct-sequence offers a trade-off between complexity and noise rejection compared to non-quantized DSSS and making a good representation of the digitized signals to implement the required DSSS in mobile wireless communications.


Article
The Relationship between P-Wave Morphology and Atrial Fibrillation

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The objective of this paper is to develop an efficient P-wave detection algorithm based on the morphology characteristics of arrhythmias using time domain analysis. ECG from normal subjects, and patients with atrial fibrillation were studied. After baseline wander cancellation, power line interference filtration, the step of QRS detection using the pan- Tompkins algorithm is utilized to calculate R peak which represent the reference point to detect P peak. The algorithm was tested with experiments using MIT-BIH arrhythmia database which included Paroxysmal Atrial Fibrillation PAF prediction challenge, Massachusetts Institute of Technology MIT-BIH normal sinus rhythm, long term Atrial Fibrillation AF and MIT-BIH atrial fibrillation where every P-wave was extracted. The results reveal that the algorithm is accurate and efficient to detect and classify arrhythmias resulted from atrial fibrillation.

Keywords

Atrial Fibrillation --- P-wave --- QRS --- ECG


Article
Damage detection in composite plate based on vibration Measurements using Genetic Algorithm

Authors: Rafal Taha Abdulhussein --- Muhammad A.M.
Pages: 709-718
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Abstract

The effect of defect on structures and machines has negative consequences on them and it always takes researchers concern and attention in order to find feasible solutions to trace and detect the location of the defect accurately. In this research, the effect of a hole with different diameters on a square composite plate is studied as well as the effects of both the boundary condition and the plate thickness, furthermore, Vibration analysis of composite plate has been studied numerically and experimentally. The Numerical analysis has been carried out by using FEM by building MATLAB program as well as (ANSYS 15). The experimental part of this research is done by using vibration measuring instruments. The rate of error among the experimental tests and the numerical solution is less than 15%. These results have been used an inputs to the Genetic Algorithm model that the defect is located by, with a high percentage of success.


Article
Influence of Friction Stir Welding Rotation Speeds In dwell phase on the Temperature Distribution of AA6061-T6 Aluminum Alloy Weldment

Authors: Rasheed Nema Abed
Pages: 719-726
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Friction Stir welding (FSW) parameters, which play a vital principle, that impact on the mechanical, microstructural properties of the weldment because of the warmth produced by the contact between the instrument and work-piece, An AA6061-T6 aluminum composite plate with measurements (186*150*4) mm3 welded through various rotational paces 800, 1000, 1200 and 1450 rpm, the created heat measured through thermocouples embedded in study zones of the Weldment, a Finite Element model have been executed by utilizing ANSYS 12.1 bundle charges to ponder the temperature appropriation amid stay stage, the outcomes demonstrates a decent assention between the after effects of exploratory and hypothetical tests. The most extreme temperature measured at this condition was 0.71 from the liquefying temperature of the sample at a maximum rotational speed of (1450) r/min.


Article
Force Convection Heat transfer from a Different Cross Section Cylinder Embedded in Porous Media

Authors: Suhad A. Rasheed --- Jasim M. Abood
Pages: 727-736
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This research presents an experimental study of forced convection heat transfer for laminar steady flows in a duct filled with saturated porous media glass balls.The heater model consists of a circular cylinder , square cylinder and triangular cylinder .The experimental work was studied the effect of changing heater section on forced convection heat transfer with selected values of heat supply ( 2455W/m2 ).The experiments were carried out for Reynolds number ( 1094 ≤


Article
Comparison of Different Types of Fitness Functions to Choose the Appropriate Attributes for Porosity Prediction

Authors: Muna Hadi Saleh --- Hadeel M. Tuama
Pages: 737-743
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Porosity is one of the most important reservoir characteristics because it indicates to fluid collection. Several techniques used to get good porosity prediction, so, in this study we employed seismic attributes and well log data in a genetic algorithm to get the best porosity prediction. The study attempt to enhance the performance of genetic algorithm for attribute selection and therefore porosity prediction by applying genetic algorithm on different types of fitness functions like average mean square error fitness, average correlation coefficients fitness and performance index fitness. Also, used two methods to represent attributes in genetic algorithm. Different witnesses applied to choose the appropriate fitness function that gives high porosity prediction.


Article
Adsorption of Copper Ions from Aqueous Solution Using Raw and Modified Can Papyrus: Experimental and Kinetic Study

Authors: Usama Akram Saed --- Noor Sabah A. Jaleel
Pages: 744-750
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The adsorptions of copper ions from aqueous solution by can papyrus were studied using batch and continuous adsorption. It has been improved surface area and efficiency of the cane papyrus using urea and thiurea at different concentrations through stirring in period of time with mixer. Results proved that cane papyrus very well in the adsorption of metal through the study of important variables and influences such as the contact time, pH in addition to the initial concentration. It was found that the effect of pH at 6 to 7 better than acid or base solution also found that the best time for adsorption to reach equilibrium is 90min and there is no effect of temperature significantly on the results observed, studied the effect of weight of the cane where found that 0.4g best weight. After treatment with urea and thiurea the results improved from the 56% removal by natural cane, 61% for urea modified and 68% for thiurea modified. For continuous adsorption the results shows that when the flow rate increase in constant bed of adsorbent the breakthrough decrease. As well as the best curve was obtained using a cane modified with thiurea weighing 2.5g in a continuous flow rate where the breakthrough curve is start from 25min to 175min. The results was applied to Langmuir and Freundlich adsorption isotherms, the results fitted will to both at correlation coefficients 0.971 and 0.9066 for Langmiur and Freundlich respectively. Pseudo second order was applied and gives better results for adsorption where R2 is 0.9941 while for pseudo first order R2 is 0.136.

Keywords

Adsorption --- Canpapyrus --- Cupper


Article
CFD Simulation of Enhancement Techniques in Flat Plate Solar Water Collectors

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Abstract

The present work is a numerical study of thermal performance of modified flat plate solar water collectors. Numerical simulations have been done by solving the governing equations (Continuity, Momentum and Energy) equations in the laminar regime , three dimensions by using the FLUENT software version (14.5). The effect of flow on temperature distribution of flat plate water collectors by inserting (twist strip with twist ratio (3), helical spring surrounding the solid shaft) inside riser pipes is numerically simulated and compared with solar collector without inserting device inside its riser pipes at flow rates of (100)ℓ/h . The numerical simulation results show that the flat plate water, solar collectors with the inserted, twist strip and helical spring that’s surround the solid shaft were higher enhancement of heat transfer than without inserted devices. The useful energy in case of twist strip is (10%) higher than the case of flat plate solar collector without enhancement device. Also, the case of helical spring is increased (6.8 %) than the twist strip, and (16.2%) than collector without enhancement device for the same mass flow rate.


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

Authors: Ahmed Waheed Mustafa --- Jaafar Ahmed Zahi
Pages: 762-769
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Abstract

The optimal spacing between elliptic tubes cooled by free convection is studied numerically. A row of isothermal elliptic 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 axis ratio of the tubes is (0 ≤  ≤ 0.5), and the working fluid is air (Pr =0.71). The results show that the optimal spacing decreases as Rayleigh number increases for all axis ratios, and the maximum density of heat transfer increases as the Raleigh number increases for all axis ratios and the highest value occurs at axis ratio ( =0) (flat plate) while the lowest value occurs at ( =0.5) (circular tube). The results also show that the optimal spacing is unchanged with the axis ratio at constant Rayleigh number.


Article
Estimating Transfer Function of Below-Knee Prosthesis at Two Phases of Gait Cycle

Authors: Mahmud Rasheed Ismail --- Imad Zuhair Ghani
Pages: 770-777
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Abstract

The modern development in prosthetics field demand the evaluation of the dynamical behavior and automatic control .The key process in the design and implement of these devices is the determination of the model parameters inherited with the transfer function .In such complicated structures it is so difficult to evaluate transfer function analytically ,however experimental approaches can serve as a simple and effective tool for estimating transfer function and model parameters .In this regard computer software such as Matlab is used .System Identification SID refers to the method for estimating the system transfer function from experimental tests by using computer .In the present paper; SID method is employed for analyzing below-knee prosthesis leg .In order to simulate with the practical requirement for design and evaluation ,two phases of human gait are considered ,namely; swing phase and single support of stance phase .The validity of this method is firstly checked by applying it on clamped-clamped beam model where the required parameters are evaluated and compared theoretically (via modal analysis) and experimentally (via System identification) .It is found that ; the error in estimating the transfer function parameter of beam is not exceeded 6% . Then the transfer function of the prosthesis are estimated for two phases of gait cycle .It is found that; the estimated transfer function of the prosthesis leg is highly affected by the phase type of gait cycle , where ;the natural frequency highly increases, the static gain decrease for support phase as compared with the swing phase ,however the damping ratio does not affected .


Article
The influence of the thickness of the plate on a deep forming operation of several stages

Authors: Sabih Salman Dawood AL Ghrawy --- Ali Tuaimah
Pages: 790-800
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Abstract

In this research, practical and analytical deep drawing of the several-stages design mold is produce hexagonal cup and also proved the influence of the thickness of the plate on the allocation of strain and laminating in curvature of the cup area for all stages of the drawing. Three stages deep drawing mold was designed and constructed to carry out the practical work required to produce a hexagonal cup of (28.25 mm by 24.5 mm) , (60 mm) high drawn from a circular flat plate (80 mm diameter), made from low carbon steel (1006–AISI). Analysis program (ANSYS11.0) to perform the finite element method to accomplish the analytical side of the search. Three types of thickness plate ( = 0.5, 0.7,1 mm) with constant radius of curvature of punch equal to ( =4) mm, radius of curvature of die equal to ( =8 mm) and radius of curvature of wall of die ( =4 mm) were used. From the practical and analytical results of the three stages of drawing, it has been found that drawing load less than the more advanced stages of drawing operation on the wall of cup, maximum laminating take place at curvature of the cup area with plate thickness equal to ( =0.5 mm) and maximum thickening take place at the at throat cup with plate thickness equal to ( =1 mm), the maximum values of strains (radial, hoop, thickness and effective) take place at throat cup with plate thickness equal to ( =1 mm)

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