University of Technology-IraqEngineering and Technology Journal1681-6900251020071201A Study On The Effect of Using Various Reflectivities of Output Couplers on CW Carbon Dioxide Laser Performance3333362595710.30684/etj.25.10.10ENJournal Article20071201A practical study has been carried out on axial flow CW CO2 laser by<br />changing the output coupler with a wide range of reflectivities. ZnSe mirrors<br />were used in various reflectivities (20, 30, 40, 45, 50, 55, 60, 65, 70,75,80,85,90).<br />It has been found that the output power varies considerably with varies the<br />reflectivity of the output coupler. Thus the optimum reflectivity for 1m<br />optical length and 1cm discharge tube of CW CO2 laser is found to be 65±<br />5%. Our results have been compared with other published data.University of Technology-IraqEngineering and Technology Journal1681-6900251020071201Effect of Super Plasticizer on the Properties of Pre-cast Concrete Flags Reinforced by Steel Fibers and Including Slag33735217303310.30684/etj.25.10.11ENQais J.FriehCivil Engineering Dep., University of Technology-IraqBassam A.AljabbarCivil Engineering Dep., University of Technology-IraqJournal Article20050102This research has studied the possibility of optimizing some of the properties of the precast concrete flags by using by-products of steel fragments from the CNC machines and local slag, the combined influence of these materials<br />338<br />with the water reducing agent. The local slag is produced by the blast furnace from the scrap as a raw material, which is called (steel slag). The local slag has a low activity as a cementicious material due to low content of glass since it has not been treated, and contains high ferrous ratio. The study includes the results of compressive and strength as well as transverse loading tests. Also, it includes the measurements of absorption on different curing durations of the reference concrete samples and concrete contains the metal and chemical additives, reinforced by steel fibers. This study has taken place by replacing the slag instead of fine aggregate, using ratios of (0, 10, 20, 30%) by weight of sand with the influence of steel fibers from the CNC by-products, using ratios of (0.5, 1.0, 1.5 %) by volume of the concrete mix with the influence of super plasticizer of (1.5%) ratio by weight of cement. The results had shown that the concrete compressive strength had increased with using (30%) of slag and (1%) of steel fibers of the CNC machine by- product, with (1.5%) of the super plasticizer, compared with the reference mixes. The results had shown also, that the concrete containing super plasticizer with slag (20%) and (1.0%) of the steel fibers had shown better flexural strength compared with the reference mixes at ages (7, 28 days). The results had also shown increasing in the transverse loading test of the pre cast concrete flags, especially when using slag of (30%) and steel fibers of (1%) and super plasticizer, compared with the reference mixes at ages (7, 28 days). The results had shown clear reduction of the absorption at slag ratio (30%) and (1.0%) of steel fibers with the super plasticizer, compared with the reference mixes at age (28 days).University of Technology-IraqEngineering and Technology Journal1681-6900251020071201Rapid Solidification Processing Of Al-3Wt%Mg Alloy110211092595810.30684/etj.25.10.1ENTalib Khalel IbrahimAli Sabea HumodJournal Article20071201Metallic ribbons were formed under a chill block melt –spinning<br />process conditions for Al-3 wt% Mg alloy. X-ray diffractometry, optical<br />microscopy, electron microscopy and thermoanalytical data have been used to<br />establish comparison between as–received alloy and ribbons.<br />Thermogravimetric data showed that the weight gain is lower for the<br />ribbons compared to the as –received alloy.University of Technology-IraqEngineering and Technology Journal1681-6900251020071201Numerical Investigation intoVelocity and Temperature Fields Over Smooth and Rough Ducts for Several Types of Turbulators111011272597510.30684/etj.25.10.2ENSabah Tarik AhmedWaheed S. MohammedLaith J.HJournal Article20071201Numerical study on a laminar and turbulent fluid flow and<br />temperature distribution in a rectangular duct with six types of vortex<br />generators has been carried out. A modified version of ESCEAT threedimension<br />code has been used to solve Navier-Stokes and energy equations.<br />The effect of vortex generator type, geometrical configuration, and<br />dimensions on flow and temperature in different planes has been presented.<br />The purpose of the present investigation is to highlight the complex threedimensional<br />interaction of the vortices generated by wings and other vortex<br />generators to understand how such vortices configurations structure the<br />velocity and temperature fields. Experiment in terms of velocities and<br />temperatures vectors and contours were performed on 6 configurations,<br />which experiments are (fin, fence, rib, wing-type, rectangular-type, and<br />winglet-type) vortex generators The results show good agreement with<br />published data.University of Technology-IraqEngineering and Technology Journal1681-6900251020071201Production of Organosilane by The Direct Reaction of Silicon with Methyl Chloride112811422597710.30684/etj.25.10.3ENIhsan B. HamawandFadi Z. HannaMoayed G. JalhoomJournal Article20071201The aim of this work is to study the production of organosilane by the<br />catalytic reaction of Methyl chloride (CH3Cl) with silicon (Si) and using copper<br />(Cu) as catalyst in a fluidized bed reactor. Gas chromatographic (GC) technique<br />was used on-line for analysis of the reacted gas.<br />The experimental work was carried out using columns with dimensions 5 cm<br />internal diameter and 50 cm height stainless steel used as a fluidized bed reactor.<br />Gas distributor was fitted at the bottom of column with 25 holes of 0.1cm hole<br />diameter.<br />The reaction started with experiments at different bed temperatures (200-<br />400) oC and the catalyst used is only copper (Cu) in two different percent (10 %<br />and 15 % of the silicon) in order to anticipate the optimum temperature and<br />catalyst value required for the best conversion of organosilane, these two<br />variables were kept constant for the remaining experiments.<br />Experiments were performed to reflect the effect of each of these variables:<br />particle diameter, bed height and reacted gas velocity on the organosilane<br />production. It was found that organosilane conversion was the highest at 350 oC<br />and 15% copper. The gas velocity at a value little more than minimum<br />fluidization velocity is gave better conversion than low velocity that gave fixed<br />bed or high velocity and that gave turbulent fluidization, higher level of contact<br />mass, and finally higher particle diameter this gives homogenous fluidization<br />concerning the reacted gas velocity.University of Technology-IraqEngineering and Technology Journal1681-6900251020071201Calculation of Energy Band gap of Porous Silicon Based On The Carrier Transport Mechanisms114311482597810.30684/etj.25.10.4ENAlwan M.AlwanJournal Article20071201The energy bandgap of photoluminescence porous silicon is calculated<br />based on the analysis of the current-voltage characteristics and the<br />measurements of the thermal activation energy of the zero bias and reverse<br />bias currents of PS/n-Si porous silicon diodes at different temperatures. The<br />2.1 eV bandgap resulting from these electrical measurements agrees well with<br />2 eV measured in PL spectra.University of Technology-IraqEngineering and Technology Journal1681-6900251020071201A Study On the Structure and Electrical Properties of Pbo.9Sn0.1Se/Si Heterojunction114911532597910.30684/etj.25.10.5ENAlwan M. AlwanJournal Article20071201In this work, as Study on the structural and electrical properties of<br />Pbo.9Sn0.1Se/Si hetrojunction was made by depositing compound of Lead, Tin<br />and Selenide film on Si by thermal evaporation.<br />XRD diffraction analysis of the film, shows the dominant crystal<br />orientation is (200) as well as (Pbo.9Sn0.1Se) film deposited is polycrystalline<br />structure.<br />Electrical properties of Pbo.9Sn0.1Se/Si heterojunction detector have been<br />investigated. The electrical properties under dark condition show a rectifying<br />behavior with low rectification factor, and exhibit soft breakdown reverse<br />current. C-V characteristics suggest that the fabricated diode was abrupt<br />type, built in potential determined by extrapolation from 1/C2-V curve to the<br />point (V=0) and it was equal to (0.4V).University of Technology-IraqEngineering and Technology Journal1681-6900251020071201The Biological Effects of Low Level Laser Therapy with Static Magnetic Field on Acute and Chronic Pain115411612598010.30684/etj.25.10.6ENAseel A. Al-sharifyJournal Article20071201This paper presents the biological effects of the low level laser therapy<br />(LLLT) with static magnetic field. The therapy was applied either alone or<br />combined with conventional therapy for the treatment of acute and chronic<br />pain. Two groups of volunteers with a variety of conditions were randomly<br />selected from the patients who were usually treated by conventional therapy.<br />The LLLT with static magnetic field was proposed to the first group as<br />extension of the conventional treatment. The second group underwent only<br />the LLLT with static magnetic field. LLLT was performed with an optical<br />and magnetic system specially designed for this purpose. Short–term and<br />long–term effects as well as conditions responding only to LLLT were<br />recorded. Results indicate disappearing or stable reduction of pain in most<br />cases, while partial restoration of mobility was noticed in some other cases.<br />The success of the treatment was up to 70% for both groupsUniversity of Technology-IraqEngineering and Technology Journal1681-6900251020071201A Content-Based Authentication Using Digital Speech Data116211702598110.30684/etj.25.10.7ENHanaa M. SalmanDepartment of Computer Science & Information System, University of Technology-Baghdad, IraqJournal Article20071201A watermarking technique for speech content and speaker authentication<br />scheme, which is based on using abstracts of speech features relevant to<br />semantic meaning and combined with an ID for the speaker is proposed in<br />this paper. The ID which represents the watermark for the speaker, is<br />embedded using spread spectrum technique while the extracted abstracts of<br />speech features are used to represent the watermark for the speech, embedded<br />in the original speech file using secret key. The abstracts speech feature is<br />implemented using B-spline curve interpolation. The paper provides a<br />background knowledge for the concept of speaker watermarking and contentfragile<br />watermarking based on digital speech data. Then, the suggested<br />feature based authentication scheme is developed and the results from the<br />evaluation are presented. Show that the suggested scheme is successful in<br />combining speech and speaker watermark authentication.University of Technology-IraqEngineering and Technology Journal1681-6900251020071201The Effect of Annealing Temperatures on Optical and Electrical Properties of PbTe Thin Films117111832599510.30684/etj.25.10.8ENAkram N . Al-MashhadanyNoor S. SadeqJournal Article20071201The study was carried out by the preparing of PbTe thin films and studying the<br />effect of annealing temperatures on electrical and optical properties.<br />The PbTe thin films have been prepared by thermal evaporation in a vacuum of<br />(2*10-5) Torr with thickness 500nm at room temperature and annealed at different<br />annealing temperatures of (373,423,473)K for 30 min.<br />The electrical measurements show that the PbTe thin films have two kinds of<br />activation energy which increases with increasing annealing temperature.<br />The Hall Effect measurements prove that thin films are n-type at room temperature<br />and convert to p-type by annealing temperature and it is found that<br />NH decreases with increasing annealing temperature but μH increases with increasing<br />annealing temperature.<br />The optical measurements show that the PbTe thin films have direct energy gap<br />which show that energy gap increases with increasing annealing temperatures and it<br />is found the transmittance increases with increasing annealing temperaturesUniversity of Technology-IraqEngineering and Technology Journal1681-6900251020071201Surface Preparation of Aluminum for Plating by Zincating118411932599610.30684/etj.25.10.9ENMohammed Hliyil HafizBaha Sami MahdiJournal Article20071201The objective of this work is to gain better understanding of the<br />influence of zincate bath chemistry on zincating morphology of Aluminum<br />bond pads to provide reference for zincating chemistry design and process<br />control for wafer bumping applications.