@article { author = {صالح, هيثم}, title = {ﻣﺤﻀﺮة ﺑﻄﺮﻳﻘﺔ اﻟﺮش ﺑﺎﻟﺒﻼزﻣﺎAl-SiCدراﺳﺔ ﺳﻠﻮك اﻟﺒﻠﻰ ﻟﻄﺒﻘﺔ ﻃﻼء}, journal = {Engineering and Technology Journal}, volume = {26}, number = {1}, pages = {1-9}, year = {2008}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.26.1.8}, abstract = {Due to the importance of aluminum alloys in different industrialapplications because of their light weight and maintaining their highresistance to corrosion, attention is focused on using different techniques toimprove the characteristics of these alloys. Alloys of Al-4.5%Cu are used assubstrate for coating with compound material of abase of aluminumenforced with ceramic substance (SiC) using plasma spray technique.Spraying operation has been done using (180 mm) as distance spray andconstant spraying current (550A).Heat treatments have been done usingvacuum furnace with discharge pressure 6*10-4 torr and temperature 550Cofor two hours. The testing techniques which had been used are hardnessbefore and after heat treatment, wear test after heat treatments by differentslipping distances and influence wear test on micro structure to study theeffect of addition SiC percentage and slipping distance on wear rate. Fromthe result, is seen that wear rate is decreased with increase in slippingdistance and addition percentage.}, keywords = {Plasma spry,Wear behavior in composite materials,Coating Process}, url = {https://etj.uotechnology.edu.iq/article_26056.html}, eprint = {https://etj.uotechnology.edu.iq/article_26056_3160a9cf49162a390423827ce9f8e1ef.pdf} } @article { author = {Mohammed Saeed Ridha, Maha}, title = {Nonlinear Finite Element Analysis of High Strength Fiber Reinforced Concrete Corbels}, journal = {Engineering and Technology Journal}, volume = {26}, number = {1}, pages = {1-15}, year = {2008}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.26.1.1}, abstract = {This research work presents a nonlinear fini te elementinvestigation on the behavior of high strength fiber reinforced concretecorbels. This investigation is carried out in order to get a betterunderstanding of their behavior throughout the entire loading history.The three- dimensional 20-node brick elements are used tomodel the concrete, while the reinforcing bars are modeled as axialmembers embedded within the concrete brick elements. Thecompressive behavior of concrete is simulated by an elastic-plasticwork-hardening model followed by a perfectly plastic response,which terminate at the onset of crushing. In tension, a fixed smearedcrack model has been used.}, keywords = {Corbels,fiber,finite element,nonlinear}, url = {https://etj.uotechnology.edu.iq/article_26061.html}, eprint = {https://etj.uotechnology.edu.iq/article_26061_8faaa20f131ad6c3c4a142379b8207fc.pdf} } @article { author = {}, title = {Prepare and study the magnetic properties of compacted (Fe1-xCox)}, journal = {Engineering and Technology Journal}, volume = {26}, number = {1}, pages = {10-27}, year = {2008}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.26.1.9}, abstract = {The manufacturing of electrical converter using powder-metallurgy can beconsidered as acomplex-subject due to the several variables which includefor examples, selection of raw materials, purity, and grain size. There aremany researches that have been used to study iron-nickel, iron-silicon, andso on, but the research on iron-cobalt in our country is limited and due tothe significance of core-industrial in electrical converters, barometer andcomputer devices…….etc, this work has included:1. Preparing compacted-materials of (Fe1-xCox) by using powdermetallurgyat different weight ratios (x=15, 25, 35, 50).2. studying the effect of time and temperature of sintering on magneticproperties ( permeability, coercivity force, and hystersis loop) formaterials prepared by using powder-metallurgy.3. studying the effect of different ratios of pure cobalt-powder added onmagnetic properties and microstructure of prepared materials.4. produceing different shapes and sizes of electrical-core}, keywords = {}, url = {https://etj.uotechnology.edu.iq/article_26057.html}, eprint = {https://etj.uotechnology.edu.iq/article_26057_a3a97b55330a93a7f36e52500024557e.pdf} } @article { author = {Abdulkhliq Al-Rawi, Wafaa and Salman Al-Lami, Hadi}, title = {Effect of Forming Methods on the Properties of Controlled Porous Ceramics}, journal = {Engineering and Technology Journal}, volume = {26}, number = {1}, pages = {16-28}, year = {2008}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.26.1.2}, abstract = {Two methods of forming, namely, semi-dry press and slip casting were used tofabricate porous ceramics from local raw materials, kaolin and silica. Differentwt.% of aluminum-zinc mixture powders were used as gas creative agent inchemical swelling method to create porosity in ceramic slurry before forming.Dried formed ceramics were fired at fourdifferent firing temperatures of (900, 1000, 1100 and 1200)°C.It was found that the forming technique has a great effect on the properties ofthe fabricated porous ceramics. From porosity point of view, slip casting is bettertechnique to produce high porous ceramics, but semi-dry pressing seems to begood for other physical properties and mechanical properties.}, keywords = {}, url = {https://etj.uotechnology.edu.iq/article_26071.html}, eprint = {https://etj.uotechnology.edu.iq/article_26071_a0ac947e4274b5c5fee9f4ba7615e4fc.pdf} } @article { author = {}, title = {Effect Of Applied Load On Wear Behavior Of Some Copper Alloys}, journal = {Engineering and Technology Journal}, volume = {26}, number = {1}, pages = {28-36}, year = {2008}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.26.1.10}, abstract = {This research devoted to studying the properties of sliding wear ofthree groups of copper alloys chosen to this study. They are Brass (70/30),Silicon bronze and Silicon-Brass. These three groups have been examinedby using (pin on Disc) apparatus under different wear conditions includingapplied loads and disc hardness is constant (35HRC). This study wasconcluded that the wear rate was increased as the applied load and the wearbehavior was changed from mild wear into transition wear as the appliedload is increased. This research concludes that the alloy of Silicon-brass wasthe best alloy due to high wear resistance in comparison with the otheralloys.}, keywords = {}, url = {https://etj.uotechnology.edu.iq/article_26059.html}, eprint = {https://etj.uotechnology.edu.iq/article_26059_a923bf0cf72432a0966323af930bc191.pdf} } @article { author = {Khalid Jawad, Waleed}, title = {Design Modification in a Multi-stage Deep Drawing Process}, journal = {Engineering and Technology Journal}, volume = {26}, number = {1}, pages = {29-44}, year = {2008}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.26.1.3}, abstract = {In this research an analysis of multi-stage deep drawing process is carried outfor process design of cylindrical cup drawing with large drawing ratio ( β = 3.416).A three stage deep drawing tooling was designed and constructed to carry out theexperimental work required to produce a cylindrical cup of (25mm outer diameter)formed from a circular flat blank (82 mm diameter) comprised of mild steel of(0.15%) carbon content, without any intermediate annealing. The difference in thedrawing ratio between the neighboring stages was reduced so as to achieve moreuniform deformation in the cross-section. The study confirms the real deformationmechanism and inspects the contact conditions at the tool-blank interface. In thesecond and third stage of drawing, three direct re-drawing methods were used tore-draw the cup produced from the first stage (By using internal blank holder, without blank holder, and by using centering block method).The analysis reveals that the difference in the drawing ratio, and the irregularcontact condition between the blank and die (which occur when using second andthird method of re-drawing), induces non-uniform metal flow, which causewrinkling, tearing, and severe extension of metal during the re-drawing process. forThere the first method (By using internal blank holder) was chosen for detailedanalysis because it ensures reduction in wrinkling and tearing of the cup wall.From the comparison between the results of the three stages of drawing, it hasbeen found that the drawing force decrease for each successive stage of drawingprocess, increasing the value of effective strain distribution over the cup wall withdie nose radius, the radial and hoop strain increases remarkably for each successivestage of drawing, while the thickness strain increases slightly, which lead toproduce a uniform wall thickness of the re-draw cup. It was found that, the use ofinternal blank holder in re-drawing process, increases cup formability, extends toollife by eliminating wrinkling and tearing, reduces the possibility of failures,improves part quality and increase production speed.}, keywords = {}, url = {https://etj.uotechnology.edu.iq/article_26072.html}, eprint = {https://etj.uotechnology.edu.iq/article_26072_6e522bc1a8e6f77b14742bb3895c30d1.pdf} } @article { author = {J. Al-Sulayfani, Bayar and T. Al-Taee, Hatim}, title = {Modeling of Stress-Strain Relationship for Fibrous Concrete Under Cyclic Loads}, journal = {Engineering and Technology Journal}, volume = {26}, number = {1}, pages = {45-54}, year = {2008}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.26.1.4}, abstract = {A mathematical model to predict the stress–strain behavior of fibrous concrete compositesunder random cyclic compressive loadings is developed. The envelopeunloading strain is used as an index of load history, while the plastic strain andreloading strain are predicted as functions of the envelope unloading strain for bothfull and partial unloading and reloading. The model is independent of the expressionused for the envelope curve. Comparison with cyclic data shows good agreement.The model can be used for completely random loadings, in both the pre–peak andpost–peak ranges. It is suitable for both plain and fibrous concrete composites. Themodel has been built using MATLAB language computer program facilitating theadvanced mathematicaldifficulties of solving and differentiating complex expressions.In this paper, the monotonic stress–strain curves of Al-Sulayfani model [1] for fibrousconcrete had been adopted.}, keywords = {cyclic loading,fibrous concrete,stress,Strain relationship}, url = {https://etj.uotechnology.edu.iq/article_26073.html}, eprint = {https://etj.uotechnology.edu.iq/article_26073_67fd2629cb3924f392c52c08e4ec2b2e.pdf} } @article { author = {K.Jawad, Waleed and H.Mohamed, Jamal}, title = {Studying the Effect of Punch Nose Radius on Deep Drawing Operation}, journal = {Engineering and Technology Journal}, volume = {26}, number = {1}, pages = {55-73}, year = {2008}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.26.1.5}, abstract = {This work aims to study the effect of varying punch nose radius used in deepdrawing operation, on produced cup wall thickness, stress and strain distributionacross the wall of the drawn part, hydrostatic pressure ,residual stress developed inthe drawing part after drawing, and the value of work done to form the requiredshape of drawn part.In this work, six types of punches with various nose radii have been used toform a cylindrical cup of (44mm) outer diameter,(28mm) height, and(0.5mm)sheet thickness of mild steel of (0.15%) carbon content. A commerciallyfinite element program code (ANSYS 5.4), was used to perform the numericalsimulation of the deep drawing operation, and the numerical results werecompared with the experimental work.The results show that, the value of work required to form parts with large noseradii ismuch more than the value required to form parts with small punch noseradii. An increase in the punch nose radius, results in an insignificant increase inshear stress and shear strain. These values are very small which can be ignored.The greatest thinning is seen to occur with hemispherical punch (Dome shapedpunch) due to great stretching of the metal over the punch head. The maximumtensile stresses and the maximum thinning of the dome wall occur nearly at theapex of the dome (a friction coefficient nearly equal to zero). In the presence offriction, the position of maximum strain, which corresponds to the location ofmaximum thinning point, moves away from the apex. The larger the friction is,the larger is the distance between the apex and the point of maximum thinning.The frictional force is applied to the metal largely by the edge of the punch andnot by its flat section. Maximum thickening of the cup wall occurs at the flangerim, and this thickening increases with punch stroke.}, keywords = {}, url = {https://etj.uotechnology.edu.iq/article_26074.html}, eprint = {https://etj.uotechnology.edu.iq/article_26074_d47c19d875b13182d8bbe0d5614982af.pdf} } @article { author = {A. Mahdi, Alaa and Ali Hussian, Tahseen and Mohammed Jassim, Nabeel}, title = {Laminar Natural Convection of Newtonian and Non – Newtonian Fluids in a Square Enclosure}, journal = {Engineering and Technology Journal}, volume = {26}, number = {1}, pages = {74-91}, year = {2008}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.26.1.6}, abstract = {In this investigation, steady two – dimensional natural convection heattransfer of Newtonian and non-Newtonian fluids inside square enclosure has beenanalyzed numerically for a wide range of the modified Rayleigh number of (103 ≤Ra ≤ 105), with non-dimensional parameter(NE) of Prandtl – Eyring model rangingfrom (0 to 10), and modified Prandtl number in the range (Pr* =1,10, and 100).Two types of boundary conditions have been considered. The first,is when the sidewalls are heated at different uniform temperatures and the horizontal walls areinsulated. The second, when the bottom wall is heated by applying a uniform heatflux while the other walls are at the constant cold temperature. Also, the non-Newtonian fluids under consideration were assumed to obey the Prandtl – Eyringmodel. The numerical results of the values of average Nusselt number have beenconfirmed by comparing them to similar known yeslts of previous works using thesame boundary conditions. Good agreement was obtained. The results arepresented in terms of isotherms and streamlines to show the behavior of the fluidflow and temperature fields. In addition, some graphics represent the relationbetween average Nusselt number and the parameters that are mentionedpreviously. The results show the effect of non – dimensional parameter (NE) on thevelocity and temperature profiles. It also shows that the average Nusselt number isa strong function of modified Rayleigh number, modified Prandtl number, nondimensionalparameter, and the boundary conditions. Four different correlationshave been made to show the dependence of the average Nusselt number on thenon-dimensional parameter, the modified Rayleigh and Prandtl numbers.}, keywords = {Natural Convection,Newtonian fluids,Finite Differences Method}, url = {https://etj.uotechnology.edu.iq/article_26075.html}, eprint = {https://etj.uotechnology.edu.iq/article_26075_255dd449d3fef35271515c385de2ad4b.pdf} } @article { author = {Hameed Ahmad, Adil and Khalaf Jaralla, Basim}, title = {Design and Simulation of Broadband Rectangular Microstrip Antenna}, journal = {Engineering and Technology Journal}, volume = {26}, number = {1}, pages = {92-110}, year = {2008}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.26.1.7}, abstract = {In this work, many techniques are suggested and analyses forrectangular microstrip antenna (RMSA) operating in X-band for 10 GHzcenter frequency. These approaches are: lowering quality factor, shiftingfeeding point , using reactive loading and modification of the patch shape.The design of a RMSA is made to several dielectric materials, and theselection is based upon which material gives a better antenna performancewith reduced surface wave loss. Duroid 5880 and Quartz are the best materialsfor proposed design to achieve a broader Bandwidth (BW) and bettermechanical characteristics than using air. The overall antenna BW for RMSAis increased by 11.6 % with Duroid 5880 with shifted feeding point and withcentral shorting pin (Reactive loading) while that for Quartz is 17.4 %.Modification of patch shape with similar improving techniques gives anoverall increasing VSWR bandwidth of 26.2 % for Duroid 5880 and abandwidth of 30.9 % for Quartz. These results are simulated using MicrowaveOffice package version 3.22, 2000.}, keywords = {}, url = {https://etj.uotechnology.edu.iq/article_26076.html}, eprint = {https://etj.uotechnology.edu.iq/article_26076_e45fab74ff248261bc730ec7d307b36b.pdf} }