Study the effect of the chemical heat treatments on mechanical properties steel (40 Cr)
text
article
2008
eng
This work deals with improvement of the mechanical properties of low alloy steel (DIN 40Cr) using surface thermochemical heat treatments ,Carbonizing, Nitriding, andCarbonitriding. Carborizing processes were performed at 900 – 950 Cº for 3hrs. Nitridingprocesses were performed at 570Cº for 1.5 hrs. Carbonitriding processes were performed at840 Cº for 3hrs. Some specimens were oil quenched at 860 Cº followed by tempering at 500Cº. The microstructure, tensile, hardness, and impact tests were measured. The resultsshowed that Carbonizing, Nitriding, and Carbonitriding processes caused improvement ofmechanical properties of low alloy steel. However specimens that were subject to quenchingand tempering had better mechanical properties than specimen that were subject tocarbonizing, Nitriding, and carbonitriding.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
324
334
https://etj.uotechnology.edu.iq/article_26705_02edddacb7b5cde94543000d0261dd55.pdf
dx.doi.org/10.30684/etj.26.8.15
A Novel Deployable Open Ends Support Reflector
Adnan
D. Mohammed
author
Adnan
D. Mohammed
author
Muhsin
J. Jweeg
author
text
article
2008
eng
This paper presents an improved deployable reflector concept for an Earthobservation mission that requires a low-cost L-band Synthetic Aperture Radar(SAR) satellite. The required reflector shape is an offset parabolic cylinder with anarc length of 7.888 m and a width of 3.2 m. A novel hollow solid structuralconcept is proposed that comprises curved surfaces formed from thin sheets ofcarbon-fiber-reinforced-plastic (CFRP) connected by flexible hinges along theedges. This proposed structure has very high stiffness-to-weight-ratio, because ofits thin-walled box-type construction. A preliminary design of the full-scalestructure in deployed configuration, which has an estimated mass 22.5 kg and18.665 kg and fundamental natural frequency of 0.72 Hz and 0.64 Hz before andafter the optimization analysis respectively, is presented in the paper. This is 3.5 to4.2 times lighter than the traditional reflector structure, made from lightweightcurved panels with self-locking hinges. A detailed study of a quarter-scaletechnology demonstrator made of 0.6mm thick thermoplastic (nylon), includingdesign, manufacture and testing is also presented.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
894
906
https://etj.uotechnology.edu.iq/article_26688_cff8ee7ab5786e19352aa84f96af6783.pdf
dx.doi.org/10.30684/etj.26.8.1
Application of Artificial Neural Network In Cathodic Protection of Carbon Steel Pipe In Sea Water
Sami
Abulnoun Ajeel
author
Ghalib
A. Ali
author
text
article
2008
eng
The intelligent techniques are used successfully in a broad band of applicationsone of these applications is the cathodic protection system. Examples of thesetechniques used in cathodic protection are fuzzy logic and genetic algorithms. Thepresent work aims to use the neural network to predict the minimum currentdensity required in impressed current cathodic protection to protect low carbonsteel pipe which have been related previously.[1].This work deals with choosing the best network architecture for cathodicprotection system. This step used multilayer feed forward network fourenvironment variables (concentration C%, temperature T, distance D and pH) asinput to identify the minimum current density as output in a feed forward networkstructure with one hidden layer using the practical results data for the learningprocess. The best number of neurons in the hidden layer is chosen by trial and errorand it is found to be 25 neurons. the decision function used is the tan trainingalgorithm with one variable learning rate. Then, neural network training is doneusing 25 data samples from the experimental data for the current density in theabove four variables conditions. The stopping criterion for training was to obtain asum square error of 0.001 or read 10000 Epochs. An (SSE) than 0.001 wereobtained after 5226 Epochs.Generalization test used 5 data samples taken from the experimental resultsother than those data samples used in the learning process to check theperformance of the neural network on these data. The SSE for these samples was0.0053 and it shows a good generalization results for our application. Thecomparison between the actual experimental output and the neural network out putafter the learning process are almost identical which indicates that good learningprocess was achieved.The practical results indicate that neural network system can be usedsuccessfully to obtain minimum cathodic protection current density to protect lowcarbon steel pipes.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
907
918
https://etj.uotechnology.edu.iq/article_26689_8fd7951350c429306dc7ac8c8d1348d0.pdf
dx.doi.org/10.30684/etj.26.8.2
Diffusion of various liquids to tubular shaped fiber reinforced composites
Hussein
Ali Hamid AL-Abdly
author
Najat
j. Salah
author
Adnan
A. AbdulRazak
author
Hassen
Sh. Majdi
author
text
article
2008
eng
In present work tubular –shaped fiber reinforced composites weremanufactured by using two types of resins ( Epoxy and unsaturated polyester) andseparately reinforced with glass, carbon and kevlar-49 fibers (filament and wovenroving), hybrid reinforcement composites of these fibers were also prepared. Thefibers were wet wound on a mandrel using a purposely designed winding machine,developed by modifying an ordinary lathe, in winding angle of 55° for filament.Various liquids were allowed to diffuse into the composite samples, where allcomposite samples were immersed in water, HCl (0.5N, IN) and NaOH (0.5N, 1N).The exhibited behaviors were mainly explained in accordance to Fick’s –law.However, there were few case of anomalous behavior observed.The observed difference in diffusion rate for acidic and basic solutionsmay be explained in terms of different permeability of OH- and H+ ions in thecomposite samples. This permeability was also found to be affected by thedebonding process which might be initiated by the liquid penetration. Diffusioncoefficients were also deduced and their relatively higher values are indicative forsome damage mechanism taking place in the composite and not the pure matrix.UP composite exhibited higher values than EP composite which suggest that higherdamage has taken place in UP-composite.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
919
937
https://etj.uotechnology.edu.iq/article_26690_40a1382f5c25ca25a8151cb156e32e66.pdf
dx.doi.org/10.30684/etj.26.8.3
Properties of Inclined Silicon Carbide Thin Films Deposited By Vacuum Thermal Evaporation
Khalid
Z. Yahiya
author
Ammar
H. Jraiz
author
Najem
Abdu Al-Kazem
author
text
article
2008
eng
In this work, thermal evaporation system was employed to deposit thin films of SiC onglass substrates in order to determine the parameters of them. Measurements includedtransmission, absorption, Seebak effect, resistivity and conductivity, absorption coefficient,type of energy band-gap, extinction coefficient as functions of photon energy and the effectof increasing film thickness on transmittance. Results explained that SiC thin film is an ntypesemiconductor of indirect energy and-gap of ~3eV,cut-off wavelength of 448 nm,absorption coefficient of 3.4395x104cm-1 and extinction coefficient of 0.154. Theexperimental measured values are in good agreement with the typical values of SiC thinfilms prepared by other advanced deposition techniques.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
938
943
https://etj.uotechnology.edu.iq/article_26691_4b74e50c037d6419d1dc528df206a7c8.pdf
dx.doi.org/10.30684/etj.26.8.4
An Approach For Forming Spur Gear Tooth Profile
Safaa
H. Abdulrahman
author
Adnan
D. Mohammed
author
text
article
2008
eng
Due to high working speed requirement in industry of rotating components, geardesign development become quite noticeable and rapid in the vicinity of engineeringparameters which become to have a large effect on its performance. In this work the spurgear of straight tooth is chosen because of its wide usage in industry, also an equationfor joining the involute profile and fillet curve is generated. Variation effect on the shapeof tooth profile forming is studied. A suggested method for generating tooth profile isobtained and a computer program is written for drawing the involutes and trochoidcurves. The results obtained from the new method are the true continuous involute andtrochoid curves in comparison with those obtained from Mechanical Desk softwarewhich are approximated curves fitted results.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
944
957
https://etj.uotechnology.edu.iq/article_26693_a1f5d07268f1416c9f87f28e16723eff.pdf
dx.doi.org/10.30684/etj.26.8.5
Hydroxyapatite Coating Improved Corrosion Resistance of 316L Stainless Steel Used For Surgical Implants Applications
sami
Abualnoun Ajeel
author
Nabeel
Alawi kadhim
author
text
article
2008
eng
Incidences of failure of stainless steel implant devices reveal the occurrence ofsignificant localized corroding pitting and crevice corrosion. To reduce corrosion andachieve better biocompatibility, the alloy of stainless steel was coated by hydroxapatite(HAP) by electrphoretic depositing method.The study involves modified surface of 316L stainless steel by coating it withhydroxyapatite by electrophoretic deposition. The method was carried out in various timeintervals (from 1 to 5 minutes) at constant potential of 60 V. The electrochemical behaviorof 316L stainless steel (uncoated and HAP coated specimens) was studied in simulatedhuman body environment. Synthetic blood plasma was utilized for simulated body fluidconditions.The corrosion parameters obtained from open circuit potential and potentiadynamicpolarization for the specimens indicate nobler shift in the polarization parameters, OCPtime,corrosion potential (Err) and corrosion current density (Icorr), for all coated specimensin comparison with the uncoated specimen. The final corrosion results for the alloy indicatedthat the specimen coated for 3 minutes was found to be more noble and have optimumcorrosion properties compared with the other coated specimens.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
958
970
https://etj.uotechnology.edu.iq/article_26694_2b8957cb33bbccc5de0ef9710bcf0951.pdf
dx.doi.org/10.30684/etj.26.8.6
Mathematical Modeling of Conversion CO To CO2 in Batch Mode CO2 Laser System
Adawiya
J. Haider
author
Duha
S. Ahmed
author
Hind
J. Jawad
author
text
article
2008
eng
The oxidation of carbon monoxide CO over supported noble metal catalyst is animportant part of the catalytic control in sealed-off TEA CO2 laser system. In this model,the activities of supported noble metal catalysts (Pt/Al2O3 and Pd/Al2O3) separately inremoval CO as CO2 gas phase are studied at isothermal conditions. A batch equation is usedin this model to study the effect of reaction rate parameter k (sec −1 ) on conversion processesat contact time t =2500 (sec) and to control the path of gases from and the reactor cavity toindicate the effect of contact time. These results are confirming that the dissociated gases areremoved by using catalysts to regenerate CO2 molecules during the electrical discharge.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
971
975
https://etj.uotechnology.edu.iq/article_26695_e6dcfef8b94505637a12886c1695d099.pdf
dx.doi.org/10.30684/etj.26.8.7
Design of Free – Form Planar Closed Curves Using Four Point Interpolation
Wissam
K.H
author
Hussam
L. Alwan
author
Bushra
B. Abd Alhassan
author
text
article
2008
eng
It is desirable to construct a free-form closed curve, since large numbers ofmechanical elements follow these curves. In this work we present a parametricinterpolation for construction a free form closed curves using four point interpolationtechnique. The problems and solutions approach for closing open or disjoint curves isdemonstrated taking C1 continuity as a criterion for the solution of these problems.When the coordinates of any number of control points are introduced, the proposedalgorithm constructs and closed the intended curve. The designer is free to vary andmanipulate these control points to change the shape of the desired curve.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
976
985
https://etj.uotechnology.edu.iq/article_26696_a78b1b8c3105bbed3d2efd4906afbc77.pdf
dx.doi.org/10.30684/etj.26.8.8
Starting Performance Analysis of Single-Phase Capacitor Motor Using Finite Element Method
Krikor
S. Krikor
author
Dhari
Y. Mahmood
author
Maha
K. Yousif
author
text
article
2008
eng
This paper presents the starting performance analysis of the single-phase capacitor motorand the effect of motor capacitor on the starting performance. The analysis approach is basedon 2-D finite element method for the transient case, with the software (ANSYS V.8). Thevalidity of the proposed analysis method is verified by experimental values which are foundto be in good agreement.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
986
994
https://etj.uotechnology.edu.iq/article_26698_8bb4f4adf45c302dc35a7c40aa139f44.pdf
dx.doi.org/10.30684/etj.26.8.9
Electrical Characteristics of Silicon p-n Junction Solar Cells Produced by Plasma-Assisted Matrix Etching Technique
Oday
A. Hamadi
author
Ban
A.M. Bader
author
Afnan
K. Yousif
author
text
article
2008
eng
In this work, plasma-induced matrix etching technique was used to fabricate p-n junctionsolar cells and their electrical characteristics were studied. Results showed reasonableimprovement in solar cell characteristics when compared to the characteristics of thecells fabricated without etching process or by conventional thermal evaporationtechnique. The maximum conversion efficiency of the fabricated cells was about(2.15%) at irradiation power of (90W/cm2) and the fill factor was (56.90%).الخصائص
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
995
1001
https://etj.uotechnology.edu.iq/article_26700_e6bc1376f8fc0e5cc901ee036f578e71.pdf
dx.doi.org/10.30684/etj.26.8.10
Dynamically Loaded Analysis of The Adjustable Hydrodynamic Pads Bearing
Muhannad
Z. Khelifa
author
Ali
H. Zaibel
Iraq
author
Haider
Kh.Mehbas
author
text
article
2008
eng
This paper presents the instantaneous journal center velocity under dynamic loadfor adjustable hydrodynamic four pads bearing. The velocity is calculated by mobilitymethod in different values of length - diameter ratios (0.25, 0.5, 0.75 and 0.95). Finitedifference method was used to solve the Reynolds equation in two dimensions. Thisequation includes the total oil film thickness (oil film thickness and elastic deformationpad material due to generated pressure ).The effects of many parameters were studiedsuch as dynamic coefficients (stiffness and damping coefficients) and power loss on thebearing performance. The results proved that the journal center velocity and mobilitycomponents is affected by the sign of the eccentricity ratio components, also themaximum value of the journal center velocity is determined by the values of the length -diameter ratios. The vertical stiffness coefficient (Kyy) and damping coefficient (Cyy)increase as the eccentricity ratio increased. The power loss were found increase whenlength diameter ratio increase.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
1002
1015
https://etj.uotechnology.edu.iq/article_26701_c2bbc69dd0c382f65aead443769e6247.pdf
dx.doi.org/10.30684/etj.26.8.11
Factors Affecting the Relationship Between Total Porosity and Electrical Resistivity for Concrete Repair Materials
Maan
Salman Hassan
author
text
article
2008
eng
The paper examines the properties of five different types of repair and substratematerials, including conventional mortar, fly ash mortar, silica fume mortar, conventionalconcrete substrate, and high-performance concrete substrate materials. Assessment wascarried out on the basis of some physical properties (total porosity, and electrical resistivity).These properties were measured at early age and later after 14 weeks of exposure conditionsto 6 % (by weight) of sodium chloride solution to simulate typical marine environment.The results show that the electrical resistivity and total porosity measurements appearto be related and the measurements obtained are affected by the pore structure of thematerials. It is also expresses that if a material has grater proportion of coarse aggregates (e.g.the substrate concrete in this study) it will appear to have a lower porosity although theporosity of mortar surrounding the aggregates could be higher. This makes comparisonsbetween materials containing different aggregates proportions and size difficult.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
1016
1024
https://etj.uotechnology.edu.iq/article_26702_01a9f3b5faa2ed12af078e28574b92d7.pdf
dx.doi.org/10.30684/etj.26.8.12
Mathematical Model For Estimation of Desublimated Solid Layer Thickness and Surface Temperature
Wameath
Shawki Abdul-Majeed
author
text
article
2008
eng
The thickness of the desublimatd solid layer is an important parameter required forevaluation of such desublimation process, especially in the case of solid layers productionneeded for special applications. A mathematical model has been derived based on theanalogy of heat and mass transfer to calculate the solid layer thickness of the desublimatedlayer during the operation period. The prediction of thickness from the derived model isbased on the data related to the applied experimental conditions as well as the physicalproperties of the vapour-gas mixture inside desublimator. The calculated thickness from themodel has been used to calculate the temperature gradient of the solid layer surface duringthe run period.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
1025
1035
https://etj.uotechnology.edu.iq/article_26703_6151b4e8966628c94c89c6e34ff6dd4d.pdf
dx.doi.org/10.30684/etj.26.8.13
Properties of High Performance Mortar Using Local Additives
Husain
M.Husain
author
Zain
A. Raouf
author
Wasan
I. Khalil
author
text
article
2008
eng
High performance mortar can be produced by using ultrafine particles and superplasticizeradmixtures which reduce water – cement ratio (less than 0.3). In this investigation an attemptwas made to examine the possibility of replacing a part of weight of sand (10 and 20%) or apart of weight of cement (11.5, 17 and 23%) by low cost locally feldspar powder (FP) withoutimpairing the high strength characteristic of the mortar. The experimental work includes thepreparation of the feldspar material as one type of pozzolana, and selection of highperformance mortar mix. Finally the properties of the selected mortar (compressive strength,modulus of rupture, density, pulse velocity, static and dynamic moduli of elasticity) at roomtemperature at 3, 7, 14, 28, 60, 90 and 180 days and after exposure to high temperatures in therange from 150 to 900°C at age 60 days were investigated.The results show that the incorporation of 17% of feldspar powder as a partial replacement ofcement and 4% of superplasticizer by weight of cement to 1:1 cement to sand mortar mixenabled the production of high performance mortar with compressive strength of about 80N/mm2 at 28 days. This mix shows significant drop in compressive strength and modulus ofrupture of about 45 and 60% respectively, while the reduction in static and dynamic moduliwas about 66 and 86% respectively after exposure to 600°C.
Engineering and Technology Journal
University of Technology-Iraq
1681-6900
26
v.
8
no.
2008
1036
1054
https://etj.uotechnology.edu.iq/article_26704_b510012d5a80499b7cb6b8a04b02bf7d.pdf
dx.doi.org/10.30684/etj.26.8.14