Journal of University of Babylon

‎ Friction stir processing (FSP) is an emerging surface engineering technology that can eliminate ‎casting defects locally by refining microstructures, thereby improving the mechanical properties of ‎material. This paper presents the effects of FSP on microstructure and mechanical properties of cast ‎aluminum alloy grade at three different transverse speeds viz. (116, 189 and 303) mm/min under two ‎different rotational speeds 450 and 710 rpm. On processing, the work material was observed to have ‎increased tensile, yield, impact strengths, ductility properties and hardness. The observations have been ‎elaborated in detail along with the microstructures of parent and processed samples. Different heat ‎treatment methods like annealing, normalizing and quenching have been applied to the samples of ‎tensile test to evaluation mechanical properties like ultimate tensile strength, yield strength and ‎percentage of elongation. Also results showed that when rotational speed increase and transverse ‎speed decrease, the temperature was measured increase too.‎

The feasibility of sawdust as low cost adsorbent to remove methylene blue from aqueous ‎solutions was investigated through batch and column studies. Batch experiments were carried out with ‎treated sawdust and commercial activated carbon to compare the adsorption behavior of them in ‎terms of their adsorption capacities with the initial concentration of 100 mg/L and solution pH of 5. ‎Equilibrium data were fitted to Langmuir and Freundlich isotherm models. The equilibrium data were ‎best represented by the Langmuir isotherm model, with maximum monolayer adsorption capacity of ‎‎30.11 mg/g for sawdust while 39.09 mg/g by using activated carbon. In column experiments, fixed bed ‎adsorption of methylene blue was performed on sawdust columns and the breakthrough curves were ‎determined by varying bed depth, flow rate and influent concentration. The highest operating time of ‎‎1200 min. was obtained using 50 mg/l initial dye concentration, 20 cm bed height, pH of 5, and ‎‎3.33*10-6 m3/sec flow rate. ‎

The Haditha reservoir in Iraq was selected as case study to be used in the numerical models, because it ‎possesses the two relevant types of reservoir sedimentation processes (delta formation and density ‎current). It represents a case where the reservoir storage capacity losses are substantial. In order to reduce ‎capacity losses. The delta formation was simulated for fixed and fluctuating water level in the reservoir, ‎including the simulation of the formation of channels in the delta.‎
The model was a previous run for simulating delta formation, and by subsequently applying the ‎gradual water drawdown procedure used in the Haditha reservoir, the actual removing process of the ‎accumulated sediment was simulated. In this study the different processes and phenomena related to ‎reservoir sedimentation were simulated in successful way for a real and a schematized reservoir, whereas ‎also flushing as mitigation measure was fairly well simulated when compared with the practice in Haditha ‎reservoir. However more studies and a proper calibration and verification are needed to predict the ‎sedimentation processes more accurately before using the model for design purposes.‎

This study is focuses with the possibility of using Tanser SS2 geogrid as a reinforcement material ‎to increase the bearing capacity and reduce settlement under strip foundation located on sandy soil with ‎cylindrical cavity. Forty five laboratory model tests were conducted using a steel box with 1250 mm in ‎length, 800 mm in depth and 250 mm in width. Increment loads were applied on strip footing with 100 mm ‎in width and 250 mm in length. Since the length of the model foundation was approximately the same as ‎the width of the test box and length of the cavity, it can be assumed that an approximate plane strain ‎condition exist during the tests. For each model, the relationship between the applied pressure and the ‎corresponding settlement was detected. ‎
From the results of a series of laboratory tests, it was found that the bearing capacity ratio (BCR) ‎of the soil increases with increasing in width of geogrid, (b/d) specially when the cavity center coincides ‎with the centerline of the strip footing (X/d=0). The effect of geogrid width will reduce with moving the ‎cavity away from the strip footing. When the width of the geogrid layer was high (b/d), the maximum ‎increase in bearing capacity ratio can be noticed at high depth of geogrid layer (h/d=3), and this bearing ‎capacity ratio becomes very low at small geogrid width for same value of (h/d=3). ‎
At zero lateral distance ratio (X/d) and two layer reinforced, the higher generated bearing ‎capacity are noted when the vertical distance between two layer geogrid is (S/d=1, i.e optimum value), but ‎at (S/d=0.5), the values of footing resistance are lowest. The effects of number of layer (N) on the bearing ‎capacity of strip footing are very small at low value of geogrid width. At geogrid width (b/d >1), the ‎case of geogrid (N=3, i.e optimum value) record the highest values of the bearing capacity ratio. The ‎location of peak strain readings of the geogrid surface is depends upon the cavity position. As the geogrid ‎layers were near to the base of the footing, the values of reinforcement strains were increased.‎

To know water quality for multi uses in the north of Hilla city, it is important to study the quality of the ‎water parallel with the quantity. In this research, two national methods are adopted to evaluate and ‎judge the suitability of Euphrates River in this zone (study case) for irrigation use. These methods are ‎the water quality index (WQI) of the Canadian and Bhargava model. ‎
‎ The main river passing through the north of Hilla city is Euphrates River and his branch Hilla River, ‎the uses of its water are different and its use for irrigation depends on many environmental ‎parameters. The researcher studied the quality of this river for irrigation use during 2011. Took four ‎stations on the river in Babylon (Euphrates River/AL-Musiab, Euphrates River/Kifil, Hilla River/ ‎Hindia barrage and Hilla river/Hilla. The main results showed that there is no difference between the ‎two techniques at significance level (0.08) and the quality of the river inter the boarder classified as ‎GOOD and FAIR according to Bhargava and the Canadian method respectively. Also that there is a ‎serious deterioration in the water quality downstream Al-Kifil station because of the local drains that ‎discharge in the river. These results ensure the need to receive higher water quality at the boarders ‎‎(quantity and quality) to raise the quality in the downstream the river.‎

In this paper, the Invasive Weeds optimization( IWO) is exploited to produce the array ‎radiation pattern that is nearest to the desired objective which exhibits sidelobe level (SLL) suppression ‎and/or null placement. The inter-element position of even element Linear Arrays Array (LAA) is ‎optimized and relocated whilst maintaining uniform excitation over the array aperture and the phase ‎of the antenna . IWO method is utilized here as an adaptive beam former that makes a uniform linear ‎antenna array steer the main lobe towards the Direction of Arrival (DoA) of a desired signal, form nulls ‎towards the respective DoA of several interference signals and achieve low side lobe level (SLL). The ‎IWO algorithm can be successfully used to locate the optimum element positions based on symmetric. ‎The results obtained showed that the IWO algorithm is capable of finding the optimal solution in most ‎cases with superior performance over conventional and particle swarm optimization (PSO) methods.‎

‎ Permanent deformation of subgrade soil is the accumulation of plastic deformation due to ‎continuous repeated loads from traffic. The main objective of this study is to investigate some of the ‎factors that affect the permanent deformation of stabilized subgrade soil such as additive type, ‎moisture content, applied stress, curing time and additive percentage. In this research soil samples were ‎tested in the standard case without additive and with the additive, two types of additives have been ‎used (cement and hydrated lime).The test procedure and test results conducted on original soil and ‎treated soil are presented. Soil-lime mixtures were tested under three levels of stress (28, 42, 63) KPa, ‎three curing conditions (3days at 50°C, 7days at 40°C and 28 day at 22°C)with three percents of lime ‎‎(3% is the optimum lime content),at various moisture contents and dry density corresponding to 95% ‎maximum dry density .The permanent deformations are monitored during 60 load cycles, and the ‎accumulated permanent deformations are determined.‎

This study concerns with electrochemical technique known electrocoagulation used to treat a ‎high polluted effluent whereby sacrificial anodes corrode to release active coagulant precursors into ‎the solution. Response Surface Methodology (RSM) was applied in the development of modeling, ‎statistical analyzing, and interpreting the resulted treatment data of textile wastewater by ‎electrocoagulation, besides response, residual, probability, surface and contour plots. A central ‎composite design has been used for the simultaneous study of the effects of operation time and the ‎current density on electrocoagulation responses. The effectiveness of the considered design parameters ‎was well examined to find the optimum experiments with less lack of fit. Models to perform simulated ‎regressions with one response gives the best fitted equation of second-order functions of two factor ‎variables that has been obtained to find optimum removals. The optimum conditions for predicted ‎maximum COD, TSS and Turbidity removals were found to be (56.54 min. and 20mA/cm2), (53.13 ‎min. and 20 mA/cm2) and (54.74 min. and 20 mA/cm2), respectively.‎

‎ This study aims to investigate the effects of applying the direction diverting blocks, ‎‎(DDBs),fixed on an ogee spillway surface with different slope on energy dissipation. Three ogee spillway ‎models were prepared with slope of 1:1, 0.85:1, and 0.75:1. All models were constructed with a scale ratio ‎of 50:1. Six sizes of DDBs of triangular shapes were used. These blocks were arranged in eighteen ‎configurations for slope 1:1, fourteen configurations for each spillway models with slope 0.85:1 and ‎‎0.75:1. The configurations differ in spacing between rows of blocks and the number of rows. ‎
‎ Eight hundred and forty six test runs were carried out to investigate the energy dissipation ‎downstream the three spillway models with and without using DDBs in different configurations. Froude ‎Number and the distance of the hydraulic jump, measured from the toe of the weir, were used as a ‎measure of flow energy and to provide a base for comparisons.‎
When DDBs were used, the maximum reduction in Froude Number was 36%, 89%, and 93% for ‎spillway models with slopes 1:1, 0.85:1, and 0.75:1, respectively. A full reduction in the values of hydraulic ‎jump distance was achieved in the three spillway models. The DDBs were efficient in reducing the distance ‎of the hydraulic jump, and as a result, if the DDBs are used, then the stilling basin will be much shorter or ‎may be eliminated.‎

‎ An experimental study for turbulent two-phase flows agitated by an impeller in a mixing tank is ‎presented. All the experiments carried out in a stirred tank with three types of impellers. conductivity meter ‎method has been used to evaluate the mixing time, effect of sodium chloride trace, impeller geometry, its ‎speed and flow rate of gas phase on mixing time has been investigated. Results show that the mixing time ‎is dependent on the amount of tracer added to the system, and decreasing with increasing the impeller ‎speed into single and two phase systems. Also, is shown that different flow regimes can affect the final ‎concentration of conductimeter.‎

The purpose of this study is to investigate the effect of Ti additions on corrosion resistance of ‎high copper dental amalgam. Ti addition is added in different percentages of ( 0.1, 0.2, 0.3, 1, 2, 3 ‎wt%). The specimens were prepared according to ADA specification No. 1. The specimens have been ‎stored at 37±1 Cº using glass chamber prepared for this purpose. The corrosion test has been carried ‎out according to ASTM standard ( G5 – 87) and at 37±1 Cº. Titanium addition with mentioned ‎percentages led to shifting the corrosion potential to positive direction, corrosion rate improvement ‎‎(91%) at (3% Ti), and passive layer formation increases with increasing titanium content. Vickers ‎hardness has been measured after six months from the end of trituration, and it found that the highest ‎hardness value was of the highest titanium content amalgam.‎

‎ RF and Microwave filters can be implemented with transmission lines. Filters are significant ‎RF and Microwave components. Transmission line filters can be easy to implement, depending on the ‎type of transmission line used. The aim of this paper is to develop a set of transmission line filters to do ‎practical work with. There are different transmission lines due to different RF and Microwave ‎applications. The characteristic impedance and how easy it is to incise precise lengths are two ‎important characteristics of transmission lines; thus they are used to investigate which transmission ‎line to use to implement filters.The first part of this paper looks into which transmission line to use to ‎erect a filter. Then the different filter design theories are reviewed. The filter design theory that allows ‎for implementation with transmission lines is used to design the filters. Microstrip transmission lines are ‎used to implement transmission line filters. They are the transmission lines with which it is easiest to ‎change the characteristic impedance. This paper presents a new approach that can be easily involved ‎in the implementation of the radio frequency and microwave (RF/MW) circuits for many ‎applications. The approach is based on the implementation of the system using MATLAB simulink. ‎

‎ This paper discusses the studies properties of the optical transmission system in optical fiber ‎based on bragg gratings and uniform fiber Bragg gratings used through fiber optic of the two channel ‎and stimulations are performed using Optisystem software . Due to its versatile advantages Fiber Bragg ‎grating are widely used in many optical systems as band filters, dispersion compensators, in-fiber ‎sensors or fiber grating lasers and amplifiers. By simulating a model of communication system and ‎using the most suitable settings of the system which include input power (dBm), fiber cable length ‎‎(km), there are two different parameters that will be investigated which are Bit Error Rate( BER) and ‎Qulity Factor (Q )at the receiver.‎

‎ In the present work, effect of addition AgNO3 on some optical properties of polystyrene has ‎been studied . for that purpose, many samples has been prepared by adding AgNO3 on the polystyrene ‎by different volume percentages from these salts with polymer and by different thickness.The ‎absorption and transmission spectra has been recorded in the wavelength range (190-1100)nm. The ‎absorption coefficient and energy gap of the indirect, allowed, forbidden transition have been ‎determined. ‎

Multivariate statistical techniques namely factor analysis and cluster analysis were applied to ‎evaluate spatial variations, and to interpret measured water quality data set in Tigris river at Baghdad. ‎The water quality was monitored at seven different sites, along the water line, over a period of one ‎year (2011) using 14 water quality parameters. When factor analysis was applied, three factors were ‎identified, which were responsible from the 86.750% of the total variance of the water quality in the ‎Tigris river. The first factor called the anthropogenic factor explained 49.829% of the total variance ‎and the second factor called the erosion and rainfall factor explained 24.967% of the total variance. ‎While, the third factor called the pH factor explained 11.954% of the total variance. Hierarchical ‎cluster analysis was used to classify seven stations with similar properties and results distinguished ‎three groups of stations. Results revealed that, water quality in Tigris river was strongly affected from ‎anthropologic influences. Thus, these methods are believed to be valuable to help water resources ‎managers understand complex nature of water quality issues and determine the priorities to improve ‎water quality.‎

‎ In this paper, an active fourth order band pass analog filter is designed and simulated. The filter is ‎designed such that it has butter worth response. The topologies that will be used to implement the filter ‎are the multiple feed back (MFB) and Sallen-Key in order to compare between them to decide the best ‎one. The filter is designed for radio frequency identification (RFID) system reader to reject all signals ‎outside the band (10-20) kHz and to amplify the low antenna signal. This is because the identification ‎number signals which are transmitted from the tag of RFID are (12.5 kHz) and (15.65 kHz).So the ‎pass band of the filter is taken to be (10-20) kHz. The values of the resisters and capacitors of the filter ‎circuit using the Sallen-Key and MFB topologies are calculated and the circuits are then simulated with ‎the MULTISIM program to reach the final conclusion which describes the result of simulation ‎compared to the simulation of the transfer function of the filter using MUTLAB program.‎

‎ Two experimental models are built to investigate the effect of a geometric arrangement of building ‎distribution over populated lands in urban areas; they are traditional and reciprocal models. The ‎experimental results show that the heat transfer and temperature degrees variation is much more ‎active and effectible for reciprocal (chess) arrangement model than traditional arrangement Model. ‎The study indicates that with an 1) initial temperature of 23.3oC for the inner space of the buildings ‎and for cooling process, traditional and reciprocal modes offer 20.9oC and 20.4oC after 70 minutes ‎respectively. Whereas for heating process, traditional and reciprocal models offer 45.8oC and 48.5oC ‎after 70 minutes respectively.2) initial temperature of 39.4oC for the inner space of the buildings and ‎for cooling process, traditional reciprocal models offer 25oC and 21.5oC after 70 minutes respectively. ‎Whereas, for heating process, traditional and reciprocal models offer 46oC and 49oC after 70 minutes ‎respectively. ‎

This research aims to investigate how to increase the structural strength of reinforced concrete ‎deep beam with large openings. Two approaches are under consideration; the first is the effect of steel ‎reinforcement bars near the opening edges, and the second is attaching CFRP layers around the ‎opening. The software ANSYS 12.1 is used to handle the nonlinear finite element analysis. The ‎ultimate strength of reinforced concrete deep beam with opening obtained by ANSYS 12.1 show fair ‎agreement with experimental results (despite the high complexity of the problem), with a difference of ‎no more than 21%. The present work concludes that using a circular opening instead of a square one ‎with the same size can save a 19% of structural strength. Also, the introducing of steel bars around the ‎opening increases the strength by up to 48%, while the using of CFRP laminates enhances the strength ‎by an amount of up to 29% for beams considered in the present research. ‎

This study deals with ultrasonic pulse velocity tests done on concrete to find out its compressive ‎strength with different mix ratios, different water cement ratios and in different ages. The cubes used ‎were 150x150x150mm and the batches were prepared using three mix ratios 1:1:2,1:1.5:3 and 1:2:4 ‎respectively. For each batch three water cement ratios were used 0.4,0.5 and 0.6. The concrete cubes ‎were tested at 3,7,14 and 28 days age in the compression machine. Before testing any cube, it was ‎tested by an ultrasonic pulse tester to find out the velocity of the waves through concrete. Ansys ‎software version11 was used to do the analytical work through so many runs to get the compression ‎stresses in concrete and the displacement in z-direction (the direction of applying the load).A ‎comparison was done between the experimental and analytical work through so many graphs in the ‎study. The maximum percentage difference between the results of the two was between (6.4-7.8)% ‎where the results of the Ansys were presented in two ways upper and lower bounds. The difference ‎seems to be reasonable ,but a care must be taken in concrete assessment. ‎

‎ Concrete is a critical material for the construction of infrastructure facilities throughout the world. A ‎new material known as Reactive Powder Concrete (RPC), or sometimes called Ultra-High Performance ‎Concrete (UHPC), is becoming available that differs significantly from traditional concretes. It is an ‎ultra high strength and high ductility composite material with advanced mechanical properties. It ‎consists of special concrete whose microstructure is optimized by precise gradation of all particles in the ‎mix to yield maximum density.‎
Different RPC mixes in the experimental investigation of the present study the mechanical ‎properties of RPC including compressive strength, density and absorption.‎
The main variables used in the production of the different RPC mixes of the present research ‎are three, namely, type of pozzolanic admixture (metakaolin, micro silica, and silica fume), type of ‎fibers (steel and polypropylene fibers) and volume fraction of fibers (1.0,1.5, and 2.0)%.‎
The experimental results indicated that RPC mixes with silica fume gave the highest values of ‎compressive strength and density and lowest value of absorption in comparison with RPC using micro ‎silica or metakaolin where metakaolin was the third in such comparisons. However the RPC mixes ‎used in the present investigation gave group compressive strength ranging between 164 -195 MPa.‎
It was also found that the use of steel fibers with high volume fraction (2%) in an RPC mix ‎increases the compressive strength by 8% and density of the concrete by 2.5% and reduces its ‎absorption by 13%, unlike an RPC mix using polypropylene fibers of lesser volume fraction.‎

This paper explores the idea of tailoring the profile of reinforcing fibers to improving buckling ‎strength of composite plates. This paper analyzes the uniaxial buckling behavior of composite laminates ‎with variable fiber spacing using eight node iso parametric finite element methods. The present ‎investigation is limited to single layer composites having parallel fibers. The non uniform spacing fiber ‎results in variable elastic stiffness and non uniform pre buckling stress field, which are shown to have a ‎pronounced influence on the buckling strength. Numerical results are obtained for seven non uniform ‎distributions E-glass fibers in epoxy matrix in rectangular plates with types of boundary condition, and ‎range of aspect ratio. The redistributions are seen to increase the buckling load by as much as 75 % for ‎proposed distribution equation. ‎

Iraqis are becoming increasingly concerned about environmental pollution and the limitations of ‎water treatment processes. A review is made to report sources and of tastes and odors in potable water ‎supplies. ‎
The field survey indicate occurrence of 102 odors and 79 tastes problems with maximum ‎Threshold 35 , 70 respectively in taps during the period of 2006 to 2012 for metropolitan area in the ‎city of Hilla, attributed to various sources; and use of ‎‏11248‏‎ Point¬of¬use treatment devices in kitchen ‎appliance.‎
Approach for controlling the problem was carried out by experiment using a chamber of 1 m3 ‎with tree trunks on top. The results shown about 99% of the taste and odors attributed to various ‎sources were removed with detention time 3- 4 hours, which can be similar to the detention time in ‎typical basin, and tree trunks can be used for one season or three months.‎