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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
Sun Dec 01 2024
Journal Name
Russian Journal Of General Chemistry
Synthesis, Characterization, and Biological Evaluation for New Derivatives Based on 2Сhloro-N-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]acetamide
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Publication Date
Sat Dec 01 2018
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Evaluating the supervision tools of the Central Bank of Iraq to verify the continuity of private banks: An applied research in the Central Bank of Iraq
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The aim of the research to highlight the calendar of the most important tools used by the Central Bank of Iraq, in the implementation of the function of supervisory oversight, to verify the stability of the banking system, and protect the funds of shareholders, and depositors in general and the absence of any raises the risks of default and financial failure in particular, for commercial banks. The most important flaws and weaknesses in these tools, in the early detection of the risks of continuity in a timely manner, The study concluded a set of conclusions, including the weakness of the tools used in the performance of the function of supervisory oversight in detecting cases of default and financial failure in the early time as well as

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Publication Date
Sat Jul 01 2023
Journal Name
International Journal Of Research In Management
The role of network marketing for the Iraqi cement company in improving entrepreneurial behavior (An exploratory study of the opinions of a sample of company leaders)
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Publication Date
Fri Jun 01 2012
Journal Name
Journal Of The College Of Languages (jcl)
An Investigation of Iraqi Fourth-Year University Students’ Recognition of Presupposition Through The Linguistic Triggers
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Presupposition is the background belief that is known by both the speaker and the addressee, it is tied to particular words and aspects of the surface structure that act as linguistic triggers. The present study aims at investigating whether Iraqi fourth -year university students are able to recognize the English presuppositions through the meaning of these linguistic triggers .To fulfil the basic requirements of the study, the researcher has conducted a test . The results of the study have validated the hypothesis of the work and it is found that the linguistic triggers are important tools in recognizing presuppositions.    

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Publication Date
Mon Feb 10 2025
Journal Name
Aip Conference Proceedings
Development of an HPLC method for the determination of tramadol hydrochloride using ZIC-HILIC columns
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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
Tue Feb 01 2022
Journal Name
Advanced Powder Technology
Functionalization of mesoporous MCM-41 for the delivery of curcumin as an anti-inflammatory therapy
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Publication Date
Thu Sep 15 2022
Journal Name
Journal Of Baghdad College Of Dentistry
Immunohistochemical evaluation for integrin binding sialoprotein on healing process of intrabony defect treated by bone sialoprotein
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Background: Bone defect healing is a multidimensional procedure with an overlapping timeline that involves the regeneration of bone tissue. Due to bone's ability to regenerate, the vast majority of bone abnormalities can be restored intuitively under the right physiological conditions. The goal of this study is to examine the immunohistochemistry of bone sialoprotein in order to determine the effect of local application of bone sialoprotein on the healing of a rat tibia generated bone defect. Materials and Methods: In this experiment, 48 albino male rats weighing 300-400 grams and aged 6-8 months will be employed under controlled temperature, drinking, and food consumption settings. The animals will be subjected to a surgical procedure o

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Publication Date
Sat Nov 30 2024
Journal Name
Research Journal Of Chemistry And Environment
Evaluation of blue textile dye decolorization by immobilized polyphenol oxidase using pumice stone under optimum conditions
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Industrial dyes are major pollutants in wastewater and river water with an initial visible concentration of 1 mg/L. Recent studies have shown the possibility of using polyphenol oxidase in catalytic biological treatment due to its ability to oxidize a large number of dyes and pollutants in wastewater and the flexibility to work in wide ranges of temperature, pH and salinity. It is easy availability as well as the low economic cost resulting from its use in biological treatments, this enzyme polyphenol oxidase was used. The findings in this study showed that the extraction of polyphenol oxidase (PPO) from potato peel was homogenized with potassium phosphate buffer (0.1 M, pH 7) at a ratio of 1:10 (weight: volume) for two min. The res

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Publication Date
Fri Sep 15 2023
Journal Name
Journal Of Baghdad University College Of Dentistry
Immunohistochemical evaluation for integrin binding sialoprotein on healing process of intrabony defect treated by bone sialoprotein
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