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Enhancing Heat Transfer in Tube Heat Exchanger by Inserting Discrete Twisting Tapes with Different Positions
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Enhancement of heat transfer in the tube heat exchanger is studied experimentally by using discrete twisted tapes. Three different positions were selected for inserting turbulators along tube section (horizontal position by α= 00, inclined position by α= 45 0 and vertical position by α= 900). The space between turbulators was fixed by distributing 5 pieces of these turbulators with pitch ratio    PR = (0.44). Also, the factor of constant heat flux was applied as a boundary condition around the tube test section for all experiments of this investigation, while the flow rates were selected as a variable factor (Reynolds number values vary from 5000 to 15000). The results show that using discrete twisted tapes enhances the heat transfer rate by about 60.7-103.7 % compared with plane tube case. Also, inserting turbulators with inclined position offers maximum heat transfer rate by 103.7%.

 

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Publication Date
Sun Dec 09 2018
Journal Name
Baghdad Science Journal
Enhancement of the Tensile and the Compression Properties for Heat- Cured Acrylic Resin Denture Base Materials
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This work aims to investigate the tensile and compression strengths of heat- cured acrylic resin denture base material by adding styrene-butadiene (S- B) to polymethyl methacrylate (PMMA). The most well- known issue in prosthodontic practice is fracture of a denture base. All samples were a blend of (90%, 80%) PMMA and (10%, 20%) S- B powder melted in Oxolane (Tetra hydro furan). These samples were chopped down into specimens of dimensions 100x10x2.5mm to carry out the requirements of tensile tests. The compression strength test specimens were shaped into a cylinder with dimensions of 12.7mm in diameter and 20mm in length. The experimental results show a significant increase in both tensile and compression strengths when compared to cont

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Publication Date
Sun Jun 30 2013
Journal Name
Al-kindy College Medical Journal
Neural Tube Defects in Iraq
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1.
Embryonic Origin of Neural Tube Defects.
Insaf Jasim Mahmoud
2.
Etiology of Neural Tube Defectss.
Ali Abdul Razzak Obed
3.
Epidemiology of Neural Tube Defects in Iraq.
Mahmood Dhahir Al-Mendalawi
4.
Surgical Management of Neural Tube Defects.
Laith Thamer Al-Ameri
5.
Prevention of Neural Tube Defects in Iraq.
Mahmood Dhahir Al-Mendalawi

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Publication Date
Sat May 25 2024
Journal Name
Optical And Quantum Electronics
Enhancing plasma jet parameters control by external magnetic field strength variation
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Abstract This research scrutinizes the impact of external magnetic field strength variations on plasma jet parameters to enhance its performance and flexibility. Plasma jets are widely used for their high thermal and kinetic energy in both medical and industrial fields. The study employs optical emission spectroscopy to measure electron temperature, electron density, and plasma frequency in a plasma jet subjected to varying magnetic field strengths (25, 50, 100, 150, and 250 mT). The results indicate that a stronger magnetic field results in higher electron temperature (1.485 to 1.991 eV), electron density (5.405 × 1017 to 7.095 × 1017), and plasma frequency 7.382 × 1012 to 8.253 × 1012 Hz. As well as the research investigates the influ

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Publication Date
Sat Dec 30 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Charge Transfer Between d-p States in Ti02 By Employing Compton Scattering Techniques
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The com pton profiles for Ti02 have been measured using a SCi

Am-241 compton spectrometer .A pellet of the oxide was prepared from a polycrystalline powder    having a thickness of 1.54 mm ,about J 00000  counts   have   been  accumulated   at   the  compton   peak

.Theoreti cal compton profiles have been calculated for different ionic anangements using free atom compton profile for the core electrons.The   theoretical  and  experimental  results  ahrce  well  for (Ti/4(0 .2    arrangement which support complete transfer of valence electrons from metal to oxygen ions, i.e., full ionic &nbs

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Publication Date
Sat Mar 31 2018
Journal Name
Journal Of Engineering
Effect of Using Extra Fins on the Pin Fin Classic Geometry for Enhancement Heat Sink Performance using EGM Method
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In the present study, the effect of new cross-section fin geometries on overall thermal/fluid performance had been investigated. The cross-section included the base original geometry of (triangular, square, circular, and elliptical pin fins) by adding exterior extra fins along the sides of the origin fins. The present extra fins include rectangular extra fin of 2 mm (height) and 4 mm (width) and triangular extra fin of 2 mm (base) 4 mm (height). The use of entropy generation minimization method (EGM) allows the combined effect of thermal resistance and pressure drop to be assessed through the simultaneous interaction with the heat sink. A general dimensionless expression for the entropy generation rate is obtained by con

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Publication Date
Tue Aug 22 2017
Journal Name
Heat Transfer—asian Research
Thermal Enhancement from Pin Fins by Using Elliptical Perforations with Different Inclination Angles
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Abstract<p>Many of the proposed methods introduce the perforated fin with the straight direction to improve the thermal performance of the heat sink. The innovative form of the perforated fin (with inclination angles) was considered. Present rectangular pin fins consist of elliptical perforations with two models and two cases. The signum function is used for modeling the opposite and the mutable approach of the heat transfer area. To find the general solution, the degenerate hypergeometric equation was used as a new derivative method and then solved by Kummer's series. Two validation methods (previous work and Ansys 16.0‐Steady State Thermal) are considered. The strong agreement of the validation results (0.3</p> ... Show More
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Publication Date
Mon Jan 01 2024
Journal Name
Dental Hypotheses
Effect of Surface Treatments with Plasma and Chemical Bond on Shear Bond Strength of Acrylic Denture Teeth to Flexible and Heat-Cured Denture Base Material: An In Vitro Study
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Introduction: We aimed to evaluate the shear bond strength of acrylic denture teeth to flexible and heat-cured denture base material after surface treatments with argon plasma, chemical bonding agent (PALFIQUE universal), and combination. Methods: A total of 80 incisor acrylic denture teeth were treated with a argonplasma, chemical bond (PALFIQUE universal bond), and a combination with 10 samples for each group. The neck (gingival portion) of teeth was cut at a 45° angle, and the teeth were attached to heat-cured acrylic resin and flexible denture base material. All the specimens were stored in artificial saliva for 7 days in an incubator (37 °C). A shear

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Publication Date
Wed Apr 23 2025
Journal Name
Misan Journal For Physical Education Sciences
An analytical study of the percentage of performance contribution of some defensive skills by playing positions (1,5,6) for the free player (libero) in volleyball
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The game of volleyball, like all other sports, has been made by new amendments, the most important of which is the system of what is not the system of the free player in 1998, which gave added importance to the skills of receiving the transmission and defending the stadium being one of the important skills where the law allowed the free player to move and position in the back positions of the stadium Limited support mainly defensive skills. This is to make the state of stability and balance between defensive and offensive skills, which helps in the development of the game and make it exciting and enjoyable for players and fans. Therefore, the researchers decided to shed light by identifying the percentage of the contribution of the free pla

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Publication Date
Fri Jun 15 2018
Journal Name
Journal Of Baghdad College Of Dentistry
Effect of phosphate ester addition on transverse strength and hardness of heat cured acrylic denture base material
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Background: acrylic resin denture base consider a common denture base material for its acceptable cost, aesthetic and easy processing but still has disadvantages including easy of fracture and low impact strength. Material and method: The experimental group was prepared by addition of 15% phosphoric acid 2-hydroxyethyl methacrylate ester (PA2HEME) with polymethyl methacrylate monomer; the experimental groups was compared with the control one. The specimens were prepared according to ADA specification No. 12 with dimension 65 mm x 10 mm x2.5 mm (length x width x thickness respectively). The prepared specimens were tested by three-point flexural strength utilizing Instron Universal Testing Machine (WDW, Layree Technology Co.), Shore D hard

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Publication Date
Wed Apr 23 2025
Journal Name
Journal Of Baghdad College Of Dentistry
Clinical evaluations for the masticatory efficiency of heat cure resin and flexible types of denture base materials
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Background: The aim of this study was for estimation and comparism of masticatory efficiency in patient wearing heat cured acrylic and flexible base partial denture, finding out the role of peanuts and carrots on the measurement of chewing efficiency, and to find out whether the types of P.D. (being single or two opposing each other) has any effect on the masticatory performance. Materials and methods: Twenty partially edentulous patients were selected. Five of these patients were selected having Kennedy class I with no modification against natural dentition, other 5patients having Cl.I against Cl.I . The other 5 patients having Cl.III against natural dentition and the last 5 patients were with Cl.III against Cl.III. several ways were used

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