ORIGINAL_ARTICLE
A Study On The Effect of Using Various Reflectivities of Output Couplers on CW Carbon Dioxide Laser Performance
A practical study has been carried out on axial flow CW CO2 laser bychanging the output coupler with a wide range of reflectivities. ZnSe mirrorswere used in various reflectivities (20, 30, 40, 45, 50, 55, 60, 65, 70,75,80,85,90).It has been found that the output power varies considerably with varies thereflectivity of the output coupler. Thus the optimum reflectivity for 1moptical length and 1cm discharge tube of CW CO2 laser is found to be 65±5%. Our results have been compared with other published data.
https://etj.uotechnology.edu.iq/article_25957_c84e2b85dd222928f88c86bb33be2165.pdf
2007-12-01
333
336
10.30684/etj.25.10.10
Laser
cw laser
Reflectivity
ORIGINAL_ARTICLE
Effect of Super Plasticizer on the Properties of Pre-cast Concrete Flags Reinforced by Steel Fibers and Including Slag
This 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 materials338with 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).
https://etj.uotechnology.edu.iq/article_173033_9097c6bee6ad4ddf923d8d937f6e75e6.pdf
2007-12-01
337
352
10.30684/etj.25.10.11
Pre-cast Concrete
Steel Fibers
Slag
Qais
Frieh
bce.19.77@grad.uotechnology.edu.iq
1
Civil Engineering Dep., University of Technology-Iraq
AUTHOR
Bassam
Aljabbar
2
Civil Engineering Dep., University of Technology-Iraq
AUTHOR
ORIGINAL_ARTICLE
Rapid Solidification Processing Of Al-3Wt%Mg Alloy
Metallic ribbons were formed under a chill block melt –spinningprocess conditions for Al-3 wt% Mg alloy. X-ray diffractometry, opticalmicroscopy, electron microscopy and thermoanalytical data have been used toestablish comparison between as–received alloy and ribbons.Thermogravimetric data showed that the weight gain is lower for theribbons compared to the as –received alloy.
https://etj.uotechnology.edu.iq/article_25958_3085283bca2bad192f95ce2d76664063.pdf
2007-12-01
1102
1109
10.30684/etj.25.10.1
Talib
Khalel Ibrahim
1
AUTHOR
Ali
Sabea Humod
2
AUTHOR
ORIGINAL_ARTICLE
Numerical Investigation intoVelocity and Temperature Fields Over Smooth and Rough Ducts for Several Types of Turbulators
Numerical study on a laminar and turbulent fluid flow andtemperature distribution in a rectangular duct with six types of vortexgenerators has been carried out. A modified version of ESCEAT threedimensioncode has been used to solve Navier-Stokes and energy equations.The effect of vortex generator type, geometrical configuration, anddimensions on flow and temperature in different planes has been presented.The purpose of the present investigation is to highlight the complex threedimensionalinteraction of the vortices generated by wings and other vortexgenerators to understand how such vortices configurations structure thevelocity and temperature fields. Experiment in terms of velocities andtemperatures vectors and contours were performed on 6 configurations,which experiments are (fin, fence, rib, wing-type, rectangular-type, andwinglet-type) vortex generators The results show good agreement withpublished data.
https://etj.uotechnology.edu.iq/article_25975_bb4ef28e43cee99dfbff62295445528e.pdf
2007-12-01
1110
1127
10.30684/etj.25.10.2
Vortex Generator
Three
Dimensional flow
Wall function
Laminar and Turbulent
Sabah
Tarik Ahmed
1
AUTHOR
Waheed
S. Mohammed
2
AUTHOR
Laith
J.H
3
AUTHOR
ORIGINAL_ARTICLE
Production of Organosilane by The Direct Reaction of Silicon with Methyl Chloride
The aim of this work is to study the production of organosilane by thecatalytic reaction of Methyl chloride (CH3Cl) with silicon (Si) and using copper(Cu) as catalyst in a fluidized bed reactor. Gas chromatographic (GC) techniquewas used on-line for analysis of the reacted gas.The experimental work was carried out using columns with dimensions 5 cminternal diameter and 50 cm height stainless steel used as a fluidized bed reactor.Gas distributor was fitted at the bottom of column with 25 holes of 0.1cm holediameter.The reaction started with experiments at different bed temperatures (200-400) oC and the catalyst used is only copper (Cu) in two different percent (10 %and 15 % of the silicon) in order to anticipate the optimum temperature andcatalyst value required for the best conversion of organosilane, these twovariables were kept constant for the remaining experiments.Experiments were performed to reflect the effect of each of these variables:particle diameter, bed height and reacted gas velocity on the organosilaneproduction. It was found that organosilane conversion was the highest at 350 oCand 15% copper. The gas velocity at a value little more than minimumfluidization velocity is gave better conversion than low velocity that gave fixedbed or high velocity and that gave turbulent fluidization, higher level of contactmass, and finally higher particle diameter this gives homogenous fluidizationconcerning the reacted gas velocity.
https://etj.uotechnology.edu.iq/article_25977_8f916568e0694d3c17422c511d095686.pdf
2007-12-01
1128
1142
10.30684/etj.25.10.3
Organosilane
direct reaction of silicone with methyl chloride
Ihsan
B. Hamawand
1
AUTHOR
Fadi
Z. Hanna
2
AUTHOR
Moayed
G. jalhoom
3
AUTHOR
ORIGINAL_ARTICLE
Calculation of Energy Band gap of Porous Silicon Based On The Carrier Transport Mechanisms
The energy bandgap of photoluminescence porous silicon is calculatedbased on the analysis of the current-voltage characteristics and themeasurements of the thermal activation energy of the zero bias and reversebias currents of PS/n-Si porous silicon diodes at different temperatures. The2.1 eV bandgap resulting from these electrical measurements agrees well with2 eV measured in PL spectra.
https://etj.uotechnology.edu.iq/article_25978_982d818b12bd4aff1be2fca25ed4534c.pdf
2007-12-01
1143
1148
10.30684/etj.25.10.4
Alwan
M.Alwan
1
AUTHOR
ORIGINAL_ARTICLE
A Study On the Structure and Electrical Properties of Pbo.9Sn0.1Se/Si Heterojunction
In this work, as Study on the structural and electrical properties ofPbo.9Sn0.1Se/Si hetrojunction was made by depositing compound of Lead, Tinand Selenide film on Si by thermal evaporation.XRD diffraction analysis of the film, shows the dominant crystalorientation is (200) as well as (Pbo.9Sn0.1Se) film deposited is polycrystallinestructure.Electrical properties of Pbo.9Sn0.1Se/Si heterojunction detector have beeninvestigated. The electrical properties under dark condition show a rectifyingbehavior with low rectification factor, and exhibit soft breakdown reversecurrent. C-V characteristics suggest that the fabricated diode was abrupttype, built in potential determined by extrapolation from 1/C2-V curve to thepoint (V=0) and it was equal to (0.4V).
https://etj.uotechnology.edu.iq/article_25979_a8503019c97a40e46e65d009993437c2.pdf
2007-12-01
1149
1153
10.30684/etj.25.10.5
Alwan
M. Alwan
1
AUTHOR
ORIGINAL_ARTICLE
The Biological Effects of Low Level Laser Therapy with Static Magnetic Field on Acute and Chronic Pain
This paper presents the biological effects of the low level laser therapy(LLLT) with static magnetic field. The therapy was applied either alone orcombined with conventional therapy for the treatment of acute and chronicpain. Two groups of volunteers with a variety of conditions were randomlyselected from the patients who were usually treated by conventional therapy.The LLLT with static magnetic field was proposed to the first group asextension of the conventional treatment. The second group underwent onlythe LLLT with static magnetic field. LLLT was performed with an opticaland magnetic system specially designed for this purpose. Short–term andlong–term effects as well as conditions responding only to LLLT wererecorded. Results indicate disappearing or stable reduction of pain in mostcases, while partial restoration of mobility was noticed in some other cases.The success of the treatment was up to 70% for both groups
https://etj.uotechnology.edu.iq/article_25980_cf4236cd0486293a9e41087238c3ce3f.pdf
2007-12-01
1154
1161
10.30684/etj.25.10.6
Aseel
A. Al-sharify
1
AUTHOR
ORIGINAL_ARTICLE
A Content-Based Authentication Using Digital Speech Data
A watermarking technique for speech content and speaker authenticationscheme, which is based on using abstracts of speech features relevant tosemantic meaning and combined with an ID for the speaker is proposed inthis paper. The ID which represents the watermark for the speaker, isembedded using spread spectrum technique while the extracted abstracts ofspeech features are used to represent the watermark for the speech, embeddedin the original speech file using secret key. The abstracts speech feature isimplemented using B-spline curve interpolation. The paper provides abackground knowledge for the concept of speaker watermarking and contentfragilewatermarking based on digital speech data. Then, the suggestedfeature based authentication scheme is developed and the results from theevaluation are presented. Show that the suggested scheme is successful incombining speech and speaker watermark authentication.
https://etj.uotechnology.edu.iq/article_25981_0b66ff657cbde09f599a25347544f690.pdf
2007-12-01
1162
1170
10.30684/etj.25.10.7
speech content authentication
digital watermarking for speaker authentication
CONTENT
fragile watermarking authentication
spline interpolation
wavelet transform
Hanaa
M. Salman
1
Department of Computer Science & Information System, University of Technology-Baghdad, Iraq
AUTHOR
ORIGINAL_ARTICLE
The Effect of Annealing Temperatures on Optical and Electrical Properties of PbTe Thin Films
The study was carried out by the preparing of PbTe thin films and studying theeffect of annealing temperatures on electrical and optical properties.The PbTe thin films have been prepared by thermal evaporation in a vacuum of(2*10-5) Torr with thickness 500nm at room temperature and annealed at differentannealing temperatures of (373,423,473)K for 30 min.The electrical measurements show that the PbTe thin films have two kinds ofactivation energy which increases with increasing annealing temperature.The Hall Effect measurements prove that thin films are n-type at room temperatureand convert to p-type by annealing temperature and it is found thatNH decreases with increasing annealing temperature but μH increases with increasingannealing temperature.The optical measurements show that the PbTe thin films have direct energy gapwhich show that energy gap increases with increasing annealing temperatures and itis found the transmittance increases with increasing annealing temperatures
https://etj.uotechnology.edu.iq/article_25995_f4c51b2561cdf0b97b5753387c85950b.pdf
2007-12-01
1171
1183
10.30684/etj.25.10.8
Akram
N . Al-Mashhadany
1
AUTHOR
Noor
S. Sadeq
2
AUTHOR
ORIGINAL_ARTICLE
Surface Preparation of Aluminum for Plating by Zincating
The objective of this work is to gain better understanding of theinfluence of zincate bath chemistry on zincating morphology of Aluminumbond pads to provide reference for zincating chemistry design and processcontrol for wafer bumping applications.
https://etj.uotechnology.edu.iq/article_25996_3513ac53835f668358ac9514ad51e973.pdf
2007-12-01
1184
1193
10.30684/etj.25.10.9
Metallization
Electrolss nickel
Zincate
Mohammed
Hliyil Hafiz
1
AUTHOR
Baha
Sami Mahdi
2
AUTHOR