2024-03-29T17:06:12Z
https://etj.uotechnology.edu.iq/?_action=export&rf=summon&issue=1516
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Influence of Electrochemical and Physical Characteristics of Reinforced Concrete on the Design of Cathodic Protection
The design aspect of cathodic protection of steel reinforcement embedded inconcrete; still implies a great deal of uncertainties, assumptions and specifications.Important features, such as design criteria, current distribution, and others are, as yetbeyond standardization.The main aim of this research is to study relationship between the induced levelof polarization and the area of the embedded steel, area of anode, the distance betweenthe cathode and anode and the level of applied external voltage. The experimentalprogram included preparing 12 reinforced concrete specimens with dimensions 20 x 30 x60 cm. The specimens were partially submerged in 3.5% sodium chloride solution.Various electrochemical and electrical measurement were carried out on polarized thespecimen using different external voltages.The results indicate differential moisture content within each specimen hasproduced different potentials along the steel bars. Greater polarization has always beenassociated with the submerged portion of the specimen.The results show that to achieve efficient design, the protected area should bedivided into discrete electrochemical zones depending on the concrete resistance andsteel potential.
2008
06
28
273
285
https://etj.uotechnology.edu.iq/article_26638_94177b7d8081d65c475780dc57767a95.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
اعادة تأهيل المنشآت وتحديثها
The Rehabilitation of old building that is in keeping with the development of countryfor new uses when the old uses has become no more needed because of the technologicaldevelopment in the buildings material such as( steel,brick and concrete) and or the newactivities .The aim of rehabilitation system in this case is to recycle an old building and to put iton to something new in the comprehensive plan of city . We see this in building likeuniversity of it – Al Beat in Baghdad as a case study.
2008
06
28
286
290
https://etj.uotechnology.edu.iq/article_26639_3ce44948b8a105dc4a4fb155703d08a8.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
قياس الدقة الهندسية لمكان العدد باعتماد الخواص الهندسية
Machines tools are used in many important modern industries especially in workshop and inmanufacturing plant, so it’s very important to study accuracy of this machines to determine and manipulationerrors that accrued by many cases, these errors affect on product accuracy.The main goal of the research is to study the geometric accuracy for Sharping & drilling machines. Duringmeasurement process for machine tools must be depended several geometric characteristics such as(Perpendicularity, Parallelism, Flatness…), In this research many testing are made on Opaeha Nehnha drillingmachine & Ctahkoc Tpontenbhbln scraping machine to determine the engineering accuracy of these machines&also to minimize the errors as much as possible to produce high quality products &minimize the rawmaterial wastages during manufacturing process. Drilling machine testing contains; testing the worktablesurface, rotation shift and loading shift. Sharping machine testing contains; testing of ram (Tool Head) andworktable surface. Testing results records in tables explain errors value from standard specifications. Theresults show errors in many accuracy testing.
2008
06
28
291
300
https://etj.uotechnology.edu.iq/article_26640_698d0144f38ba5336a99b3e77f74fa6e.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Effect of Loading Type on Generated Stresses around a Circular Tunnel Lining in Sand
T.
M. Toma
The study is carried out to investigate the behavior of tunnel lining in sandy soil byevaluating the magnitudes of the generated stresses that are generally required to ensure thesafety of tunnel construction. The testing program comprised different factors, i.e., sanddepth, density with and without the effect of surface loading. The experimental work wasaccomplished through an instrumented (strain gauged) circular tunnel model. It was shownthat the generated stresses, for different loading types, i, e., surcharge, circular or striploading, decreased as the sand density increases for all regions (Crown, Shoulder & Springline)and they increase as the sand depth increases. The results are presented in the form ofdesign charts.
Tunnels
Lining
Stresses
Loading Type
2008
06
28
602
608
https://etj.uotechnology.edu.iq/article_26626_1ed8fde6b2201f68834779b2310131b3.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
An Appropriate Traffic Routing Scheme for Node-to-Node Communications in LEO Satellite Network Using Hybrid Mesh Topology
Natiq
Abdullah Ali Al-Shammary
Since Low Earth Orbit (LEO) satellites provide short round trip delays, they arebecoming increasingly important for real-time applications such as voice and video traffic.Several strategies have been proposed for routing in a LEO satellite system. Some of themare based on the Internet Protocol (IP), the Asynchronous Transfer Mode (ATM) switching,and the Routing Sets (RS).This paper will introduce an improving for the new packet routing mechanism overinter-connected satellite networks that is the Minimum Flow Maximum Residual (MFMR)algorithm that will be based on RS concept and will give simulation results of a certainscenario. Our proposed algorithm is based on the Hybrid mesh topology (one of many meshtopologies used in LEO satellite routing). The algorithm is developed and implementedusing a software simulation in Matlab. The proposed algorithm tries to minimize themaximum flow over a given set of shortest paths from the source to destination, and also,generates minimum propagation delay paths. The propagation delay we get is less than thatof MFMR algorithm, i.e., improving the performance of the LEO satellite network by usingHybrid topology.
LEO satellite
ATM
MFMR
and Hybrid Algorithm
2008
06
28
609
619
https://etj.uotechnology.edu.iq/article_26627_bd0f6474bf8d90335bb1142570b039db.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Fabrication and Study Se/Sb on Silicon Detector Heterojunction
Khalid
Z. Yahiya
The optical response characteristics of Se/Sb thin film heterojunction deposited ona p-type silicon substrate were studied. Results indicated that the obtained isotypeheterojunction is linearly graded and has 0.8V built-in potential. Also, the maximumspectral responsivity and maximum quantum efficiency were obtained at the region of (600-650) nm and the detectivity was about 7.77x1010 cm.Hz 1/2.W-1. Response time of themanufactured detector was about 225ns. This work is a good attempt to manufacture theheterojunction detector from V and VI elements.
Isotype heterojunction
based devices
Sbx
Sex devices
Optical response
2008
06
28
620
628
https://etj.uotechnology.edu.iq/article_26628_de6318aa2caafcd5a84f364fca04811f.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Multiple Linear Model to Study Mechanical Properties of Bronze Alloys Using MATLAB Language
Amin
Daway Thamir
Abbas
Khanimas Hussein
This work include prepare five alloys of bronze (Cu-5wt.%Sn, Cu-10wt.%Sn, Cu-15wt.%Sn, Cu-20wt.%Sn, Cu-25wt.%Sn).These alloys were then subjected to tensiletests to determine the tensile strength (MPa) and elongation(%) for each alloy. Tensiletests were performed according to ASTM-E8.MATLAB language was used to determinethe mathematical model for tensile strength and elongation with respect to alloycomposition.MATLAB results showed that there is a multiple linear model betweentensile results and alloy composition.
2008
06
28
629
635
https://etj.uotechnology.edu.iq/article_26629_3451d7eb1c35ad728da1b1b044f2dd1b.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Variable Conditions Effect On Polarization Parameters Of Impressed Current Cathodic Protection Of Low Carbon Steel Pipes
Sami
Abulnoun Ajeel
Ghalib
A. Ali
Cathodic protection is an effective electrochemical technique for preventingcorrosion of metallic structures. It has widespread applications on various structures,suffering serious problems of corrosion in the environments.The main problem with this protection method is to determine the parameters(current density and potential). The previous works in this area used classical statisticalmethods to determine these parameters.In order to determine the cathodic protection potential, it is important to deal withthe electrochemical studies of open circuit potential (OCP) and polarizationinvestigations of low carbon steel used in pipeline application in 3.5 % NaCl solution attemperature range( 30- 50°C).These studies define the corrosion potential and also helpone to understand the corrosion behavior of the used metal (low carbon steel ). Thissystem was used to investigate the influence of various conditions on the minimumcathodic protection current that would provide a full cathodic protection for steel tubeimmersed in sea water. The variable conditions studied are concentration of (0.01 – 3.5)% NaCl , temperature (30- 50°C), distance between pipe (cathode) and graphiteelectrode ( anode ) of (10 – 20) cm and pH solution of (5.0 – 9.0) using a selected rangeof these conditions, the experimental results for the minimum cathodic protection currentwere obtained and recorded.The electrochemical results show that cathodic protection current density increaseswith increasing temperature and concentration. The current density also slightlyincreases with increase distance between cathode and anode.The effective sequence of these parameters on cathodic current density is as follows:Temperature > concentration > pH solution > cathode – anode distance .
2008
06
28
636
647
https://etj.uotechnology.edu.iq/article_26630_4905bf994bbde1cbe52283ef784c9ffc.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Tendency Modelling Of Desublimator For Optimization And Control
Ghanm.
M. Alwan
The study was devoted to test the effect of the process variables on the desublimator(cold trap) efficiency under vacuum technique. Since several intermediate processparameters could not be measured or inspected, then it was necessary to predict them bythe gray model. Although the novel approach (tendency model) for the desublimator wasless accurate than the detailed one, but it showed agreement results when compared withthe experimental data. The accuracy of model could be increased by increasing theprocess variable monitors. The tendency model was more effective to deal with the lackof knowledge about the process when implemented with the optimal control system.
Desublimator
Tendency model
Optimization
control
2008
06
28
648
659
https://etj.uotechnology.edu.iq/article_26631_4ba9c604ee0d72c425b804cc2d165215.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Optimum Solving SHEPWM Equations for Single Phase Inverter Using Resultant Method
Jamal
A. Mohammed
This paper represents new method to determine the optimum switching angles forSelective Harmonic Eliminated PWM (SHEPWM) inverter. Such switching angles aredefined by a set of nonlinear equations to be solved using the Resultant method. This isdone by first converting these equations that specify the harmonic elimination problem intoan equivalent set of polynomial equations. Then, using the mathematical theory ofResultants, all solutions to this equivalent problem can be found without the need for anyinitial guess. The complete solutions for unipolar SHEPWM switching pattern whichproduce the fundamental while not generating specifically chosen harmonics areinvestigated.
Harmonic Elimination
PWM
Resultant Theory
2008
06
28
660
670
https://etj.uotechnology.edu.iq/article_26632_02823817f06dc73a2e98f05c84f64478.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Slot Ventilated Room with Heated Obstruction
Waheed
S. Mohammed
Wissam
A. Mohammed
AbdulJabbar
Muttair Ahmed
A numerical study of two-dimensional turbulent buoyant rcirculating flow withinmechanically ventilated rooms is reported. The study involves the solution of elliptic partialdifferential equations for the conservation of mass, momentum, energy, turbulent energy andits dissipation rate in a finite difference form. These equations were solved together withalgebraic expressions for the turbulent viscosity and heat diffusivity, using (K-ε) turbulencemodel. A modified version of a two-dimensional elliptic computer code was used tosimulate the complex flows inside a slot-ventilated room. The present study demonstratesthat the flow behavior depends on several parameters, such as airflow rate, size andtemperature of the heated obstruction. Each of these parameters was modeled separately tounderstand their affects on the airflow characteristic inside ventilated room.
2008
06
28
671
681
https://etj.uotechnology.edu.iq/article_26633_a64b1f2616899cb8b3fc3ae432fc8a1c.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Corrosion Behavior of Bottom Plates of A potable Water Storage Tank
Mohammed
Hliyil Hafiz
This paper describes the investigation of a corrosion behavior of bottom Plates of apotable water storage tank . The tank was internally inspected for the first time afterfourteen years of service. Paint blisters and rust spots were observed on the bottomplates. Sand blasting and repainting the bottom plates and shell plates were to be usedas a remedial work .However, during the sand blasting, holes and deep pitting were observed on thebottom plates. On-site visual inspection, magnetic flux leakage (MFL) inspection,ultrasonic testing (UT), and evaluation of the external cathodic protection (CP) systemwere used in the failure analysis. The failure is attributed to the ingress of water and itsimpoundment under the tank bottom along the periphery inside the ring wall and failureof water side epoxy coating.
Coating thickness
Corrosion failure analysis
Nondestructive examination
2008
06
28
682
688
https://etj.uotechnology.edu.iq/article_26634_b2b312b6ec137747431418924495966f.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Improvement of Hot Galvanizing By Nickel Under Layer
Mohammed
Hliyil Hafiz
Zn–Ni alloy based coatings have high corrosion resistance, good adherence andunique physical as well as mechanical properties. In the present work, nickel wasdispersed in the under layer of hot dip zinc coating (Galvanizing). showed substantialimprovement in physical as well as galvanic performance. The presence of nickel in theunder layer was found to result in good adherence, less porosity and better hardness .Thepresence of nickel decreases the thickness of the coating and enhances the corrosionresistance character.
Hot dip galvanizing
Zinc coating
Galvanized steel
corrosion
Nickel coating
2008
06
28
689
698
https://etj.uotechnology.edu.iq/article_26635_a9223731220c6b743f1b5de8a5e0e664.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Oxidation Properties of Steel-T22 Alloy Coated by Simultaneous Ge-Doped 699 Chromizing-Siliconizing Process
Ahmed
A. Moosa
Diffusion coating was carried out at 1050 oC for 6 h under argon atmosphere bysimultaneous Ge-doped chromizing-siliconizing process on low alloy steel type-T22.Cyclic oxidation tests were conducted for the uncoated and for the chromizing –Siliconizing coated steel-T22 alloy at 800 oC . For the Ge-dopded chromizingsiliconizingcoated steel, the cyclic oxidation was carried out in the temperature range600-800 oC in air for 100 h at 5 h cycle. The results showed that the oxidation kineticsfor uncoated steel-T22 alloy in air at 800 oC follow a breakaway oxidation and thephases present are FeO (Wustite), Fe3O4 (Magnetite) and Fe2O3 (Haematite).The oxidation kinetics for chromizing –Siliconizing coated system in air at 800 oCwas found to be parabolic. Oxide phases that formed on coated system are SiO2 andCr2O3. The oxidation kinetics Ge-doped chromizing –Siliconizing coated system in air inthe temperature range 600-800 oC was found to be parabolic .Oxide phases that formedon coated system are SiO2 and Cr2O3. The Ge addition improves the oxidation resistanceof low alloy steel.
Steel
cyclic oxidation
Chromizing
Siliconizing
Pack Cementation
2008
06
28
699
709
https://etj.uotechnology.edu.iq/article_26636_6f2af6e84f9fc9450e44b8af5b575bbc.pdf
Engineering and Technology Journal
ETJ
1681-6900
1681-6900
2008
26
6
Harmonics Analysis and Calculation in Power System Networks
Mohammed
k.edan
Abstract- The harmonic distortion in the power system is increasing with wide use ofnonlinear loads such as wave rectifiers, static VAR compensator, and solid-state controlleddevices.Thus, it is important to analyze and evaluate the various harmonic problems in thepower system prior to their occurrence. This paper presents a technique to analyzepropagation of harmonic current and voltage in power system networks, and determine thelocation and magnitude of the maximum harmonic current and voltage in the network.Frequency dependent models of a power system elements and loads have been developedfor the appropriate range of frequency. The harmonic source representation is described.The location of harmonic source, and the system loads are all found to be factors indetermining the magnitude of harmonic currents and voltages flow in the system.
Harmonic
nonlinear load
Harmonic power flow
2008
06
28
710
724
https://etj.uotechnology.edu.iq/article_26637_bbaf449ea9471e9e5c9b63e7c744d189.pdf