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joe-2070
Evaluation of Convective Heat Transfer and Natural Circulation in an Evacuated Tube Solar Collector
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The evacuated tube solar collector ETC is studied intensively and extensively by experimental and
theoretical works, in order to investigate its performance and enhancement of heat transfer, for Baghdad climate
from April 2011 till the end of March 2012. Experimental work is carried out on a well instrumented collector
consists of 16 evacuated tubes of aspect ratio 38.6 and thermally insulated tank of volume 112L. The relation
between convective heat transfer and natural circulation inside the tube is estimated, collector efficiency, effect of
tube tilt angles, incidence angle modifier, The solar heating system is investigated under different loads pattern (i.e
closed and open flow) to evaluate the heat loss coefficient from tank and tubes, test the collector with various
aspect ratios (32.9 and 27.2). The enhancement in collector performance is studied by using two reflectors (Flat
Plate and Curved Plate) and nanofluid (Water-AL2O3).Theoretical work is run by software (Fluent 6.3), to compute
the velocity and temperature profiles within the tube, for different tube diameters, effect of tube junction angle and
stagnant region in the bottom of the evacuated tube. The experimental results shows that the heat loss coefficient
for tube is W/m2.K and for tank is W/m2.K, the maximum collector temperature is 79°C in winter and
99°C in summer, while that belong to nanofluid collector is 99°C in winter. The best tilted angle (optimum) of
evacuated tube is 41° annually. The collector efficiency increased when using nanofluid of (1, 0.6, 0.3)% volume
fraction as(28.4, 6.8, 0.6)% respectively. The efficiency decreases as (33, 62)% when decreasing tube aspect ratio
from 38.6% to 32.9% and 27.2% respectively. An increase of (16.9 and 7.08)% in collector efficiency is obtained
when using curved and flat plate reflectors respectively. From simulation the best junction angle of the tank is
22.5°. The stagnant region is influenced with changing heat flux, tilted angle and aspect ratio.

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Publication Date
Mon Apr 23 2018
Journal Name
Ibn Al- Haitham Journal For Pure And Applied Science
Performance of Strelitzia reginae Flowers Dye as Sensitizer for New Dye-Sensitized Solar Cell Fabrication
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        In current study, the dye from flowers petals of Strelitzia reginae used for the first time to prepare natural photosensitizer for DSSC fabrication. Among five different solvents used to extract the natural dye from S. reginae flowers, the ethanol extract of anthocyanin dye revealed higher absorption spectrum of 0.757a.u. at wavelength of 454nm.  A major effect of temperature was studied to increase the extraction yield. The results show that the optimal temperature was 70 °C and there was a sharp decrease of dye concentration from 0.827 at temperature of 70 °C to 0.521 at temperature of 90°C. The extract solution of flowers of S. reginae showed higher concentration in acidic media, especially at pH 4 (0.902). The

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Publication Date
Wed Oct 20 2021
Journal Name
Iraqi Journal Of Industrial Research
Annealing Effect on the SnSe Nanocrystalline Thin Films and the Photovoltaic Properties of the p-SnSe/n-Si Heterojunction Solar Cells
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A thin film of SnSe were deposited by thermal evaporation technique on 400 ±20 nm thick glass substrates of these films were annealed at different temperatures (100,150,200 ⁰C), The effect of annealing on the characteristics of the nano crystalline SnSe thin films was investigated using XRD, UV-VIS absorption spectroscopy, Atomic Force Microscope (AFM), and Hall effect measurements. The results of X-ray displayed that all the thin films have polycrystalline and orthorhombic structure in nature, while UV-VIS study showed that the SnSe has direct band gap of nano crystalline and it is changed from 60.12 to 94.70 nm with increasing annealing temperature. Hall effect measurements showed that all the films have a positive Hall coeffic

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Publication Date
Sun Mar 01 2015
Journal Name
Baghdad Science Journal
Performance evolution of a hybrid thermal solar air conditioning system and compare it with a traditional system according to Iraq weather
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In a hybrid cooling solar thermal systems , a solar collector is used to convert solar energy into heat energy in order to super heat the refrigerant leaving the compressor, and this process helps in the transformation of refrigerant state from gaseous state to the liquid state in upper two-thirds of the condenser instead of the lower two-thirds such as in the traditional air-conditioning systems and this will reduce the energy needed to run the process of cooling .In this research two systems with a capacity of 2 tons each were used, a hybrid air-conditioning system with an evacuated tubes solar collector and a traditional air-conditioning system . The refrigerant of each type was R22.The comparison was in the amou

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Publication Date
Sat Sep 15 2018
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation of the efficacy of ultrasound in the diagnosis of cervical lymphadenopathy
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Background: Cervical lymph nodes are prone to involved by a number of pathologic processes. They are common sites for lymphoma, metastasis, and reactive enlargement in a number of conditions. Aims of the study:-Clinical evaluation of patients with cervical lymphadenopathy. Differentiation between benign and malignant lymph nodes by means of ultra sounds (US) and Correlate the US findings with cytological and/or histopathological findings of cervical lymph nodes. Subjects, Materials and Methods:-The present study was carried out over a period of 6 months and included 81 patients of different age groups presenting with cervical lymphadenopathy. Each patient was examined clinically, then comprehensive sonographic examination of the neck for

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Publication Date
Thu Sep 01 2022
Journal Name
Jordan Journal Of Mechanical And Industrial Engineering
Empact of Discrete Multi-arc Rib Roughness on the Effective Efficiency of a Solar Air Heater
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Artificial roughness on the absorber plate of a Solar Air Heater (SAH) is a popular technique for increasing its effective efficiency. The study investigated the effect of geometrical parameters of discrete multi-arc ribs (DMAR) installed below the SAH absorber plate on the effective efficiency. The effects of major roughness factors, such as number of gaps (Ng = 1-4), rib pitch (p/e = 4-16), rib height (e/D = 0.018-0.045), gab width (wg/e = 0.5-2), angle of attack ( = 30-75), and Reynolds number (Re= 2000-20000) on the performance of a SAH are studied. The performance of the SAH is evaluated using a top-down iterative technique. The results show that as Re rises, SAH-effective DMAR's efficiency first ascends to a specified value o

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Publication Date
Wed Aug 05 2020
Journal Name
Neuroquantology
The Influence of Some Important Parameters on the Performance Efficiency of the Compound Parabolic Solar Concentrator
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Publication Date
Sat Apr 01 2023
Journal Name
Heliyon
Application of solar photo-electro-Fenton technology to petroleum refinery wastewater degradation: Optimization of operational parameters
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Publication Date
Mon Feb 04 2019
Journal Name
Journal Of The College Of Education For Women
Harold pinter and Iraq: An analysis of war(2003)
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Publication Date
Wed Jan 06 2016
Journal Name
Mathematical Theory And Modeling
The act of an operator and Abstract cauchy problem
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Publication Date
Tue Jun 15 2021
Journal Name
Iraqi Journal Of Pharmaceutical Sciences ( P-issn 1683 - 3597 E-issn 2521 - 3512)
Formulation and Characterization of Felodipine as an Oral Nanoemulsions
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            Felodipine is a calcium-channel blocker with low aqueous solubility and bioavailability. Lipid dosage forms are attractive delivery systems for such hydrophobic drug molecules. Nanoemulsion (NE) is one of the popular methods that has been used to solve the dispersibility problems of many drugs. Felodipine was formulated as a NE utilizing oleic acid as an oil phase, tween 80 and tween 60 as surfactants and ethanol as a co-surfactant. Eight formulas were prepared, and different tests were performed to ensure the stability of the NEs, such as particle size, polydispersity index, zeta potential, dilution test, drug content, viscosity and in-vitro drug release. Result

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