@article { author = {}, title = {Construction and Operating CO2 Laser System with Heat Distribution Technique}, journal = {Engineering and Technology Journal}, volume = {25}, number = {6}, pages = {247-255}, year = {2006}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.25.6.1}, abstract = {In this work ، a CW CO2 laser system was constructed and operated. This system employs an intermediate heat sink unit in order to increase cooling rate of the active medium, which is CO2:N2: He mixture. The obtained results in this work explain that using the heat sink unit causes the output laser power to increase to 52W compared to 5W obtained from the same system without using the heat sink unit. This heat sink technique can be considered as reasonable solution to increase cooling rate of the active medium throughout forming an intermediate region in which the gas flow rate is high.  }, keywords = {}, url = {https://etj.uotechnology.edu.iq/article_181287.html}, eprint = {https://etj.uotechnology.edu.iq/article_181287_956398b1d6fa68761e1a1db321a4d8eb.pdf} } @article { author = {Hala, M.}, title = {Synthesis Of Nucleosides Analogues Substituted With Oxy Amino Acetylenic Derivatives}, journal = {Engineering and Technology Journal}, volume = {25}, number = {6}, pages = {702-710}, year = {2007}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.25.6.2}, abstract = {This work describes the synthesis of 5-(5'-(4-disubstituted amino-butyn-2-yl)oxy-b-D-ribofuranose) uracil.For the synthesis of these compounds, 5-(b-D-ribofuranose) uracil wasconverted to its 5-(2',3'-O-isopropylidene-b-D-ribofuranose) uracil (1), itcontains the free hydroxyl group at C-5 for the required chemicalmodification. Accordingly (1) was prepared from 5-(b-D-ribofuranose) uraciland acetone using anhydrous ferric chloride (FeCl3) as Lewis acid catalyst.The treatment of (1) with propargyl bromide in benzene in a phase transferconditions in presence of tetrabutyl amonium bromide and 2% sodiumhydroxide solution yielded acetylenic ether derivative 5-(2',3'-Oisopropylidene-5'-(propyn-2-yl) oxy-b-D-ribofuranose) uracil (2), which wassubjected to Mannich reaction with secondary aliphatic amines andparaformaldehyde to give the acetylenic amino oxy derivatives (3a-f). Thetreatment of (3a-f) with sulfuric acid at room temperature affected selectivelythe removal of acetal group at 2',3'-position giving (4a-f) in good yield.The aim of the present work is the preparation of new carbohydratederivatives containing acetylenic amines soluble in water, which possess apossible biological activity.}, keywords = {Nudeosides analogues,Amino acetylenic}, url = {https://etj.uotechnology.edu.iq/article_181288.html}, eprint = {https://etj.uotechnology.edu.iq/article_181288_57260a65551db40a85ee9c2e0dd36081.pdf} } @article { author = {Sami, A. and Ahmed, N.}, title = {Study on Improvement of Casting Conditions for Some Aluminum Bronze Alloys}, journal = {Engineering and Technology Journal}, volume = {25}, number = {6}, pages = {711-727}, year = {2007}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.25.6.3}, abstract = {Two types of aluminium bronze alloys have been studied to determine theproper methods of melting and casting in two different conditions; with treatingmaterials as (Albral 2, Logas 50 and deoxidizing tube E3) and without anddetermine the effects of these conditions on mechanical properties of alloys.These alloys are :-a) Aluminium bronze alloys (AB1).b) Nickel-aluminium bronze alloys (AB2).These alloys were produced using different melting processes and cast method.The first one was made by preparing the charge materials to be melted andthen, to the cast process without using any types of additions and treatmentmaterials. The second one was made with casting conditional control, usingproper techniques of casting and using protective layers to minimize theoxidation and other casting defects. The molten metals from both processeswere poured into two types of moulds; sand and metal moulds, both types werein dimensions (Ø100×250) mm.The final products of each type of alloys in each type of conditions were used toperform many types of inspections; chemical analysis, visual test, structureexaminations, hardness test and tensile test.The results of all processes and inspections show that the properties of alloyswhich were treated and cast in metal moulds were better than that cast in sandmoulds. These alloy castings are free from shrinkage cavities, inclusions andporosities due to using suitable sequence in alloy contents melting, no overheat,reducing the melting time, selecting non-turbulence casting method and suitableselection of pouring temperatures. The mechanical properties (hardness andultimate tensile strength) for treated nickel-aluminium bronze alloys (T-AB2)were better than that for other alloys.}, keywords = {}, url = {https://etj.uotechnology.edu.iq/article_181289.html}, eprint = {https://etj.uotechnology.edu.iq/article_181289_146da156a00648d70ec867a6e35a6c10.pdf} } @article { author = {Ayad, K. and Jasim, M.}, title = {Numerical Simulation Of Two Dimensional Transient Natural Convection Heat Transfer From Isothermal Horizontal Cylindrical Annuli}, journal = {Engineering and Technology Journal}, volume = {25}, number = {6}, pages = {728-745}, year = {2007}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.25.6.4}, abstract = {Numerical solutions are presented for the transient natural convection heattransfer problem in horizontal isothermal cylindrical annuli, enclosed in heatedinner and cooled outer cylinders. Solutions for laminar case were obtained withinGrashof number based on the inner diameter which varied from 1x102 to 1x105 inair. Both vorticity and energy equations were solved using alternating directionimplicit (ADI) method and stream function equation by successive over relaxation(SOR) method. The structure of fluid flow such as a velocity vector andtemperature distribution as well as Nusselt number were obtained and the effect ofdiameter ratio on them was examined. In addition, the Grashof number waschanged with the influence of variation in Prandtle number and diameter ratio. Ournumerical calculation are summarized by Nussult number vs. Grashof numbercurves with diameter ratios and Prandtl as a parameter, which serves as a guide tonatural convection heat transfer calculated from annulus. Good agreement withprevious data is obtained.}, keywords = {Natural Convection,NUMERICAL SIMULATION,Isothermal,Cylindrical Annui}, url = {https://etj.uotechnology.edu.iq/article_181290.html}, eprint = {https://etj.uotechnology.edu.iq/article_181290_abea21b10bb09cc4f1c20918893d1a37.pdf} } @article { author = {Mohammed, A.R.}, title = {Effect of Airplane Tail Aspect Ratio on Lateral- Directional Stability}, journal = {Engineering and Technology Journal}, volume = {25}, number = {6}, pages = {746-756}, year = {2007}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.25.6.5}, abstract = {For lateral-directional stability analysis, the horizontal tail geometricparameters effect has not been considered. In the present work, the effect ofhorizontal tail aspect ratio on the lateral-directional stability derivatives,rolling static, lateral dynamic stability and Routh discriminate of the airplaneis investigated.The increasing of the horizontal tail aspect ratio improves both the rollingstatic stability and damping ability in the rolling convergence mode anddecreases the damping ability in spiral mode. The results could be used as realdesign requirements for further configuration improvements of the airplane.}, keywords = {}, url = {https://etj.uotechnology.edu.iq/article_181291.html}, eprint = {https://etj.uotechnology.edu.iq/article_181291_448252d53c787e681869ff9d4e2404e6.pdf} } @article { author = {Zaidoon, M. and Safa, A.}, title = {Mathematical Modeling Of Multi Component Batch Extractive Distillation}, journal = {Engineering and Technology Journal}, volume = {25}, number = {6}, pages = {757-774}, year = {2007}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.25.6.6}, abstract = {A dynamic model has been developed to study the dynamic behavior of multicomponent batch extractive distillation column. The set of equationsgoverning (material bvalance, heat balance, summation of mole andequilibrium equations) which represent the dynamic model are solved to givethe temperature and composition profile. Eigenvalue method was used tointegrate the stiff ordinary differential equations.Matrix method was used to solve many equations simultaeously to redefinethe column parameters during program run. Newtons algorithm was used tocalculate the plate temperatures on each tray.The calculations and simulations in this paper were obtained by usingMATLAB environment, version 6. The result of the proposed model arecompared with experimental result taken under the same operatingconditions. This model shows good agreement with experimental results andexplains features of the batch extractive distillation process.}, keywords = {Extractive Distillation,Azeotropic,Batch Distillation,Dynamic simulation}, url = {https://etj.uotechnology.edu.iq/article_181292.html}, eprint = {https://etj.uotechnology.edu.iq/article_181292_b54c4e3d34b5324f9c5a99058616e61c.pdf} } @article { author = {Ibrahem, Ali and Ali, A.}, title = {Comparative Study Between Newtonian And Non Newtonian Lubricants In Journal Bearing Using Variable Viscosity}, journal = {Engineering and Technology Journal}, volume = {25}, number = {6}, pages = {775-796}, year = {2007}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.25.6.7}, abstract = {The focus of this investigation is to study the effect of lubricant viscosityvariation on the performance of the finite width plain journal bearing withNewtonian and non–Newtonian lubricans in the steady state operation.Conventional and modified Reynolds equations in two dimensional formsare solved numerically. The change in viscosity due to temperaturevariation, using adiabatic solution, is taken into account.The results of this work on Newtonian lubricant show that the viscositydecreases under, at the same load parameter, and causes a decrease in theshear force and an increase in the side leakage flow rate and eccentricity ratio.For the non-Newtonian lubricant, at the same nonlinearity factor, the sideleakage flow rate increases due to viscosity variation, while the load capacityand shear force are decreased.}, keywords = {plain journal bearing,non–Newtonian lubricant,viscosity variation}, url = {https://etj.uotechnology.edu.iq/article_181293.html}, eprint = {https://etj.uotechnology.edu.iq/article_181293_954bfa7f91e855fc34d0e5367f7ca4f7.pdf} } @article { author = {Khalid, Z. and AmmarM, . Al-Baldawi and Ammar, H.}, title = {Study on Temperature and Etching Effects on Silicon Oxide Formation Using Laser Ellipsometric Method}, journal = {Engineering and Technology Journal}, volume = {25}, number = {6}, pages = {797-807}, year = {2007}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.25.6.8}, abstract = {In this paper, a laser ellipsometric method is implemented to study theformation of oxide films on silicon substrate at room temperature in air. Twolasers, He-Ne and semiconductor diode, as well as a tungsten halogen lamp,were used as a light source in this method to show the importance ofcoherency for accurate results. The thickness of oxide layer was measured andthe results is compared with that calculated for a monolayer of oxide.Behavior of thermally formed oxides was studied using ellipsometry todetermine polarizer angle as a function of etching time.}, keywords = {Native Oxides,Ellipsometry,Silicon devices,Laser Polarization}, url = {https://etj.uotechnology.edu.iq/article_181294.html}, eprint = {https://etj.uotechnology.edu.iq/article_181294_2a018befcb392dd80c07feb3756e6d4a.pdf} } @article { author = {Akeel, D. and Omar, A.}, title = {Phase Transformations of Hadfield Manganese Steels}, journal = {Engineering and Technology Journal}, volume = {25}, number = {6}, pages = {808-814}, year = {2007}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.25.6.9}, abstract = {In the present work, the effect of different silicon percentages that wereadded to Hadfield manganese steel on the microstructure, phases and hardnessare investigated. The results show that silicon has the crucial role in changing thehardness and Fe3C phase morphology from acicular to chunky through differentstages. X-ray diffraction line profile analysis shows that two phases are presentedin the matrix of Hadfield manganese steels; these phases are austenite and Fe3C.}, keywords = {Hadfield steel,silicon content}, url = {https://etj.uotechnology.edu.iq/article_181295.html}, eprint = {https://etj.uotechnology.edu.iq/article_181295_05aa732ef96f11953f69a901c4c82578.pdf} } @article { author = {Sami, A. and Mokdad, T.}, title = {Studying Critical Flash Over of Different Types of High Voltage Insulator}, journal = {Engineering and Technology Journal}, volume = {25}, number = {6}, pages = {815-827}, year = {2007}, publisher = {University of Technology-Iraq}, issn = {1681-6900}, eissn = {2412-0758}, doi = {10.30684/etj.25.6.10}, abstract = {The critical flashover CFO of an insulation structure is commonly used todescribe the insulation structure lightening impulse strength. In this work,first CFO of polymer and porcelain each alone was measured and then, a newstructural arrangement is represented to measure (CFO). This arrangementsconsists of three layers; fiberglass is placed between two layers of polymer andporcelain .All insulation materials are examined in dry and wet condition withpositive and negative lightening impulse under (15,25 and 35) KV. The criticalflashover voltage (CFO) of insulator is distributed on certain surface alongwith fiberglass distribution poles as an insulator. Also altitude of poles istaken into consideration in calculating critical flashover voltage for bothinsulator and structure. (CFO) voltages are added from fiberglassdistribution pole to basic insulation component and are calculated based onthe test result of the (CFO). The above measurements indicated that the totalCFO voltage of new arrangements insulator under dry condition is muchhigher than under wet condition for the same impulse polarity and tested polelength.}, keywords = {Insulation material,critical flashover,high voltage insulator,polymer insulator,Porcelain insulator}, url = {https://etj.uotechnology.edu.iq/article_181296.html}, eprint = {https://etj.uotechnology.edu.iq/article_181296_7a4e413e07ef951cba58dc37f4923543.pdf} }