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Absorber Diameter Effect on the Thermal Performance of Solar Steam Generator
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In this work, a convex lens concentrating solar collector is designed and manufactured locally by using 10 convex lenses (concentrator) of a diameter 10cm and one Copper absorber tube of a diameter 12.5mm and 1mm in thickness 1m length. Two axes manual Tracking system also constructed to track the sun continuously in two directions. The experiments are made on 17th of May 2015 in climatic conditions of Baghdad. The experimental data are fed to a computer program to solve the thermal performing equation, to find efficiency and actual useful energy. Then this data is used in numerical CFD software for three different absorber diameters (12.5 mm, 18.75 mm and 25 mm). From the results that obtained the maximum thermal efficiency for the collector of diameter 12.5mm equal to 82.3% is higher than that for the collector of 18.75 mm and 25 mm diameter. The maximum outlet temperature is found equal to (105C, 93.9C and 83.5C) for collector absorber diameter equal to (12.5 mm, 18.75mm and 25 mm) respectively. The maximum mass flow rate 0.53 kg/hr when the solar radiation intensity equal to 899 W/m2. The all-day collector efficiency varies with diameter and reaches to maximum value of (77.9%, 61.4% and 52.8) for collector diameter equal to (12.5 mm, 18.75mm and 25 mm) respectively.

 

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Publication Date
Mon Dec 20 2021
Journal Name
Journal Of Craniofacial Surgery
The Effect of Bone Density Measured by Cone Beam Computed Tomography and Implant Dimensions on the Stability of Dental Implants
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Abstract: The aim of this study was to evaluate the effect of bone density value in Hounsfield unit derived from cone beam computed tomography (CBCT), and implant dimensions in relation to implant stability parameters namely the resonance frequency analysis and the insertion torque (IT) value. It included 24 patients who received 42 dental implants (DI). The bone density of the planned implant site was preoperatively measured using cone beam computed tomography. The implant stability was measured using Osstell implant stability quotient (ISQ). The ISQ values were recorded immediately postoperatively and after 16 weeks. The IT value was categorized as 35 N/cm or > 35 N/cm. The mean (standard deviation) primary stability was 79.58 (5.27) ISQ,

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Publication Date
Sun Mar 01 2020
Journal Name
Journal Of Engineering
Study the Effect of Particle Sizes and Concentration on the Rheological Properties of Iraqi Bentonite for Using as Drilling Fluids
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The aim of this study is to identify the effect of particle size and to increase the concentration of Iraqi bentonite on rheological properties in order to evaluate its performance and to know if it can be used as drilling fluid without additives or not. In this study, Iraqi bentonite was carried out by mineral composition (XRD), chemical composition (XRF) and Particle size distribution (PSD), and its rheological properties were measured at different particle size and concentration. The results showed that when the particle size of Iraqi bentonite decreased, and the rheological properties were increased with increased concentration of Iraqi bentonite. Also, Iraqi bentonite was unable to use as drilling fluid without certain additives.

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Publication Date
Sat Jan 05 2019
Journal Name
Iraqi Journal Of Physics
Effect of the AgO content on the surface morphology and electrical properties of SnO2 thin films prepared by PLD technique
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Tin dioxide doped silver oxide thin films with different x content (0, 0.03, 0.05, 0.07) have been prepared by pulse laser deposition technique (PLD) at room temperatures (RT). The effect of doping concentration on the structural and electrical properties of the films were studied. Atomic Force Measurement (AFM) measurements found that the average value of grain size for all films at RT decrease with increasing of AgO content. While an average roughness values increase with increasing x content. The electrical properties of these films were studied with different x content. The D.C conductivity for all films increases with increasing x content. Also, it found that activation energies decrease with increasing of AgO content for all films.

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Publication Date
Mon Jun 01 2009
Journal Name
Journal Of Economics And Administrative Sciences
High performance work systems and general industrial enterprise performance
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High performance work systems and general industrial enterprise performance

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Publication Date
Sun Dec 01 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Measuring the impact of internal control on tax performance using balanced score card indicators: An applied research in a sample of the branches of the General Tax Authority in Iraq
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This research dealt with the impact of internal control on tax performance using balanced scorecard indicators because of its special importance in improving tax performance and reform. The internal control system is a safety valve for senior management in all organizations, it plays an important role in the regularity and development of work and the fight against corruption To provide reliable and accurate data and information, follow up on compliance with laws, regulations and instructions. The aim of this research is to demonstrate how control affects tax performance and how to adapt internal control components to improve tax performance. In the General Authority for taxes and its branches,. The research resulted in a number of conclu

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Publication Date
Tue May 16 2023
Journal Name
Steel And Composite Structures
Thermal buckling and stability of laminated plates under non uniform temperature distribution
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Stability of laminated plate under thermal load varied linearly along thickness, is developed using a higher order displacement field which depend on a parameter “m”, whose value is optimized to get results closest to three-dimension elasticity results. Hamilton, s principle is used to derive equations of motion for laminated plates. These equations are solved using Navier-type for simply supported boundary conditions to obtain non uniform critical thermal buckling and fundamental frequency under a ratio of this load. Many design parameters of cross ply and angle ply laminates such as, number of layers, aspect ratios and E1/E2 ratios for thick and thin plates are investigated. It is observed that linear and uniform distribution of

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Publication Date
Sat Nov 01 2025
Journal Name
Bulletin Of The Chemical Society Of Ethiopia
SYNTHESIS, CHARACTERIZATION, THERMAL PROPERTIES, AND BIOLOGICAL EVALUATION OF AZO-TRANSITION METAL COMPLEXES
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The coupling reaction between tryptamine and 8-hydroxyquinoline led to the formation of a new azo ligand. The synthesized ligand was characterized using CHN, FT-IR, UV-Vis, and NMR spectroscopic techniques. Complexes of the ligand with VO2+, Cr3+, Mn2+, and Mo6+ ions were prepared in a (1:2) ratio, with the general formula [M(L)2]. The obtained complexes were characterized using flame atomic absorption, CHN analysis, FT-IR, and UV-Vis spectroscopy, in addition to magnetic susceptibility and conductivity measurements. The findings suggest that the ligand functions as a bidentate, with the complexes exhibiting octahedral, square planar and square pyramidal geometries. All the complexes were identified as non-electrolytes. Their antioxidant ef

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Publication Date
Wed Jun 11 2003
Journal Name
Iraqi Journal Of Laser
Modeling of Plasma Affected Thermal Profile in Solids During Laser Materials Processing
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A new scheme of plasma-mediated thermal coupling has been implemented which yields the temporal distributions of the thermal flux which reaches the metal surface, from which the spatial and temporal temperature profiles can be calculated. The model has shown that the temperature of evaporating surface is determined by the balance between the absorbed power and the rate of energy loss due to evaporation. When the laser power intensity range is 107 to108 W/cm2 the temperature of vapor could increase beyond the critical temperature of plasma ignition, i.e. plasma will be ignited above the metal surface. The plasma density has been analyzed at different values of vapor temperature and pressure using Boltzmann’s code for calculation of elec

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Publication Date
Mon Mar 08 2021
Journal Name
Baghdad Science Journal
Some machnical and thermal proprties of mullite prepared from iraqi starting materials
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Some mechanical and thermal properties of mullite samples prepared by mixing different phases of alumina and silica powders have been studied according to ASTM methods the cold crushing strength of the sintcred bodies.With different porosity, at room temperature was in the range(18-54)Mpa

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Publication Date
Tue Jan 01 2019
Journal Name
Energy Procedia
Improved thermal and mechanical properties of CdBa2-x SrxCa2Cu3O8+δ superconducting compounds
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