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Force decay of orthodontic elastomeric chains by using three different mechanisms simulating canine retraction
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Background: The ideal force-delivery system must: provide optimal tooth moving forces that elicit the desired effects, be comfortable and hygienic for the patient, require minimal operator manipulation and patient cooperation and provide rapid tooth movement with minimal mobility during orthodontic therapy, the elastomeric chains have the greatest potential to fulfill these requirements. Materials and Methods: This in vitro study was designed to determine the effect of three different mechanisms for canine retraction : (6-3 , 6-5-3 and chain loop ) on the load relaxation behavior of three types of elastomeric chains : (maximum clear , maximum silver and extreme silver) from the same company (Ortho Technology company) with two different brand configurations: closed loop and open (short filament) chains under effect of time at (zero time, 24hr., 7, 14 , 21 and 28 days) in artificial saliva. Results: Statistical analysis showed that there was a highly significant difference in the mean percentage force decay for the three different mechanisms (P? 0.001).For all the three types, the 6-3 mechanism had the smallest mean percentage force decay. There was a highly significant difference in the mean percentage force decay for the different types (P? 0.001). For all three mechanisms, extreme silver elastomeric chains had the smallest percentage force decay while maximum silver elastomeric chains had the highest percentage force decay. Conclusion: This study illustrated that for all the three types of elastomeric chains, the (6-3) mechanism had the smallest mean percentage force decay. This finding suggests that it may be most efficient to retract a canine utilizing elastomeric chain directly from the molar hook to the canine bracket. The chain loop mechanism may not be indicated for space closure in vivo due to the excessive physiological force values involved with this mechanism.

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Publication Date
Sun Jun 20 2021
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
REDESCRIPTION OF SCORPIO KRUGLOVI (BIRULA, 1910) (SCORPIONES, SCORPIONIDAE) FROM THI QAR PROVINCE, SOUTH OF IRAQ
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Information on the scorpions' fauna of Iraq is limited especially in Thi Qar Province. The scorpion specimens of the present study were collected from the desert area which is located between the provinces of Thi Qar and Al-Muthana (Al-Kata'a region). The Scorpio kruglovi (Birula, 1910) redescribed in this study was found in this area. The diagnostic characters are given and the important features are figured.

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Publication Date
Tue Jun 30 2015
Journal Name
Al-khwarizmi Engineering Journal
Influences of the Twisted Strips Insertion on the Performance of Flat Plate Water Solar Collector
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Abstract

    In order to enhance the efficiency of flat plate solar water collectors without changing in its original shape and with low additional cost, twisted strips are inserted inside its riser pipes. Three flat plate collectors are used for test. Family of twisted strips are inserted inside each collector risers with different twisted ratios (TR=3,4,5). The collectors are connected in parallel mode (Z-Configuration) and are exposed to the same conditions (solar radiation and ambient temperature) .The experimental results show that, the highest heat transfer rate occurs at twisted ratio (3) .Consequently, for the same twisted ratio the daily efficiencies for the solar collector at d

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Publication Date
Sun Dec 30 2007
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
The Effect of Solvent Extraction of Light Lubricating Oil on Viscosity Index and Chemical Composition
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An investigation was conducted for the improvement of viscosity index of light lubricating oil fraction (40 stock)
obtained from vacuum distillation unit of lube oil plant of Daura Refinery, using solvent extraction process.
In this study furfural solvent was used to extract the undesirable materials which reduce the viscosity index of raw
lubricating oil fraction.
The studied effecting variables of extraction were extraction temperature range from 70 to 110°C, and solvent to oil
ratio range from 1:1 to 4:1 (wt/wt).
The n-d-M method was used for calculation of carbon distribution and structural group analysis of the raffinate
produced from furfural extraction.
Also the three component phase diagram for a mixed-ba

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Publication Date
Thu Nov 21 2024
Journal Name
Al Rafidain Journal Of Engineering Sciences
A Review of the Effect of Crumb Rubber as an Additive on Hot Mix Asphalt
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Materials recycling has a significant economic and environmental impact; as a result, steel, aluminium, plastic, and other recyclable materials have been pushed for use in construction materials. One of these recyclable materials is the crumb rubber, has been considered as a pavement component. The general behaviour of the composite rubber-hot mix asphalt system would be varied from that of the conventional rubber free mix. In this review, desirable characteristics of hot mix asphalt are highlighted first. Also, effect of gradation and the main types of rubber are specified. Afterward, many studies that considered the crumb rubber as a waste product and its associated mixture and modifiers are reviewed. The factors affect the crumb

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Publication Date
Fri Mar 01 2019
Journal Name
Iraqi Journal Of Physics
Influence of working pressure and lasing energy of Al plasma in laser-induced breakdown spectroscopy
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Aluminum plasma was generated by the irradiation of the target
with Nd: YAG laser operated at a wavelength of 1064 nm. The
effect of laser power density and the working pressure on spectral
lines generating by laser ablation, were detected by using optical
spectroscopy. The electron density was measured using the Stark
broadening of aluminum lines and the electron temperature by
Boltzmann plot method it is one of the methods that are used. The
electron temperature Te, electron density ne, plasma frequency
and Debye length increased with increasing the laser peak
power. The electron temperature decrease with increasing gas
pressure.

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Publication Date
Fri Oct 20 2023
Journal Name
Advances In Science And Technology Research Journal
Impact of TIG Welding Parameters on the Mechanical Properties of 6061-T6 Aluminum Alloy Joints
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Publication Date
Tue Aug 01 2023
Journal Name
Journal Of Engineering
The Role of Project Health Check Reports in Identifying Indicative Factors of a Troubled Project
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Government-sponsored projects in Iraq significantly improve the economic situation and provide services but face high rates of troubling blocks. This work aims to identify indicative factors of the Troubled Project using periodic health check reports based on a literature review and interviews with Iraqi experts. As a result, a questionnaire was prepared that included four sections. The first is personal information; the second section is information about knowing the level of institutions’ implementation of project management through prepared documents. The third section is about indicative factors for the project's trouble, including 25 workers; the fourth section is about the questions in the periodic reports to che

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Publication Date
Fri Jun 01 2012
Journal Name
Journal Of Engineering
Effects of Functionalized Polyethylene and Styrene ButadIene Styrene Polymers on Performance Grade of Local Asphalt
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Rutting is one of the major distresses in pavement. The objective of this paper is to develop an improved asphalt binder grading system for Iraq based on the principal of Superpave system, and increasing performance grade of product asphalt binder in Iraq using polymers without raising the viscosity of the binder. Two types of polymers are used, Plastomers, Functionalized Polyethylene (PE) which is developed by asphalt research group in Wisconsin University in the USA, and Elastomers, Styrene Butadiene Styrene (SBS) with and without cross linker. Mastercurve are drown for these modified binders, Rolling thin film aged, to show effects on rheological properties at high temperature for complex modulus (G*) and phas

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Publication Date
Mon Aug 01 2016
Journal Name
Journal Of Engineering
Modeling and Simulation of Thermal Performance of Solar-Assisted Air Conditioning System under Iraq Climate
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In Iraq most of the small buildings deployed a conventional air conditioning technology which typically uses electrically driven compressor systems which exhibits several clear disadvantages such as high energy consumption, high electricity at peak loads. In this work a thermal performance of air conditioning system combined with a solar collector is investigated theoretically. The hybrid air conditioner consists of a semi hermetic compressor, water cooled shell and tube condenser, thermal expansion valve and coil with tank evaporator. The theoretical analysis included a simulation for the solar assisted air-conditioning system using EES software to analyze the effect of different parameters on the power consumption of c

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Publication Date
Wed May 01 2019
Journal Name
Russian Journal Of Electrochemistry
Preparation and Characterization of Graphite Substrate Manganese Dioxide Electrode for Indirect Electrochemical Removal of Phenol
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Manganese dioxide rotating cylinder electrode prepared by anodic deposition on a graphite substrate using MnSO4 solution in the presence of 0.918 M of H2SO4. The influence of different operational parameters (MnSO4 concentration, current density, time, and rotation speed) on the structure, and morphology of MnO2 deposit film was examined widely. The structure and crystal size determined by X-ray diffraction (XRD), the morphology examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The γ-MnO2 obtained as the main product of the deposition process. It found that the four parameters have a significant influence on the structure, morphology, and roughness of the prepared MnO2 deposit. The crystal size in

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