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Experimental and Theoretical Study for Performance Enhancement of Air Solar Collectors by Using Different Absorbers
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An experimental and theoretical study has been done to investigate the thermal performance of different types of air solar collectors, In this work air solar collector with a dimensions of (120 cm x90 cm x12 cm) , was tested under climate condition of  Baghdad city with a (43° tilt angel)  by using  the absorber plate (1.45 mm thickness, 115 cm height x 84 cm width), which was manufactured from iron painted with a black matt.

The experimental test deals with five types of absorber:-

 Conventional smooth flat plate absorber , Finned absorber , Corrugated absorber plate, Iron wire mesh on absorber And matrix of porous media  on absorber .

The hourly and average efficiency of the collectors were investigated for three values of mass flow rates (0.016 kg/s to 0.027 kg/s) for each type of collector and then the porosity for the last collector type was tested by changing the porosity of porous media.

A typical air solar collector has been studied Theoretically to build a standard software for testing any type of air solar collectors with local weather data .

From the experimental study  it can be seen  by using some obstacle material to the air flow (fins, corrugated absorber plate, iron wire mesh porous media on the absorber) could be enhanced the efficiencies not less than 4 %  for  finned type and 8 % for corrugated and 25 % for mesh and 30  %  for porous media comparing with flat plate (smooth) collector .

Theoretically, the results showed that the collector with high convention heat transfer coefficient porous media has high  hourly efficiency about (η = 56 %) and iron wire mesh on absorber ( η = 52 % ), on the other  side the minimum  performance occurred in the  flat plate absorber  (η = 28  %).

Comparison of results reveals that the theoretical predictions agree reasonably well with experimental results. And the difference between the theoretical   and experimental efficiency in general was between (1─ 15 %).

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Publication Date
Sat Jun 01 2024
Journal Name
Journal Of Physics: Conference Series
Study of The Effect of Concentration on The Efficiency of The Sensitive N749-TiO2 Solar Cell
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In this research, we studied the effect of concentration carriers on the efficiency of the N749-TiO2 heterogeneous solar cell based on quantum electron transfer theory using a donor-acceptor scenario. The photoelectric properties of the N749-TiO2 interfaces in dye sensitized solar cells DSSCs are calculated using the J-V curves. For the 〖(CH_3)〗_3 COH solvent, the N749-TiO2 heterogeneous solar cell shows that the concentration carrier together with the strength coupling are the main factors affecting the current density, fill factor and efficiency. The current density and current increase as the concentration increases and the strength coupling increases as the N749-TiO2 heterogeneous in solar cell. However, the efficiency is more sens

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Publication Date
Thu Jun 16 2022
Journal Name
Al-khwarizmi Engineering Journal
Comparative study of vibration analysis in rotary shafts between Rayleigh's and Dunkerley's methods
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The importance of vibrations in rotating rotors in engineering applications has been examined, as has the best approach to interpreting vibration data. The most extensively used analytical approaches for rotating shaft vibration analysis have been investigated. In this research, a detailed study was made of the Rayleigh and Dunkerley methods due to their importance in the special calculations to find the amplitude of vibrations in the rotation system. The multi-node method was used to calculate both Dunkerley's and Rayleigh's methods. An experimental platform was built to study the vibrations that occur in the rotating shafts, and the results were compared with theoretical calculations and with different distances of the bearings. It pro

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Publication Date
Fri Jul 01 2022
Journal Name
Nternational Journal Of Special Education
Comparative Study between a Combination of Plants Extracts and Drugs on Thyroid Hormones and Lipid Profile in Experimental Animals
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The thyroid gland is a vital part of the overall endocrine system, which is regulated some of body function as oxygen use, basal metabolic rate, growth, cellular metabolism and development This study shed light on a number of extracts that have been shown to have beneficial effects on the thyroid and its function, as well as the various factors linked to thyroid dysfunction. The experiment was conducted to determine the effect of a mixture of two extracts of "Fucus vesiculosus (150 mg/ kg) with Coleus forskohlii (1000 mg/ kg) and Rosmarinus officinalis (220 mg/ kg) with Camellia sinensis (1.25 mg/ kg)" on thyroid hormones as well as lipids profile and tested the effectiveness of two drugs one of them stimulates the hormones of the thyroid (

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Publication Date
Fri Nov 01 2019
Journal Name
Brain, Behavior, And Immunity
Combination of cannabinoids, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), mitigates experimental autoimmune encephalomyelitis (EAE) by altering the gut microbiome
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Publication Date
Wed Nov 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
A Suggested Model for Using a Students Attendance Management Information Systems/ A Case Study In Lebanese French University/ Erbil
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This study aims to design unified  electronic information system to manage students attendance in Lebanese French university/Erbil, as a system that simplifies the process of entering and counting the students absence, and generate absence reports to expel students who passed  the acceptable limit of being absent, and by that we can replace the traditional way of  using papers to count absence,  with  a complete electronically system for managing students attendance, in a way that makes the results accurate and unchangeable by the students.

            In order to achieve the study's objectives, we designed an information syst

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Publication Date
Mon Feb 01 2021
Journal Name
Iop Conference Series: Materials Science And Engineering
Experimental Study on the Behaviours of Post-tensioned Concrete Members with Unbonded Tendons
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Abstract<p>This paper presents experimental results regarding the behaviours of eight simply supported partially prestressed concrete beams with internally unbonded tendons, focusing particularly on the effect of three different variables: concrete compressive strength, <italic>f<sub>c</sub> </italic>′; jacking stress, <italic>f<sub>j</sub> </italic>; and the prestressing index, ω. Increasing the concrete compressive strength from 35 MPa to 60 MPa was seen to lead to an increase in load-carrying capacity by about 10%. The load capacity was also affected, though to a lesser extent, by the jacking stress. The failure lo</p> ... Show More
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Publication Date
Fri Oct 01 2021
Journal Name
Journal Of Engineering
Experimental Study of Natural Convection in a Closed Cavity (Static Type Domestic Fridge)
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This work provides an analysis of the thermal flow and behavior of the (load-free) refrigerator compartment. The main goal was to compare the thermal behavior inside the refrigerator cavity to the freezer door (home refrigerator) effect and install a fan on the freezer door while neglecting the heat transmitted by thermal radiation. Moreover, the velocity distribution, temperature, and velocity path lines are theoretically studied. This was observed without affecting the shelves inside the cabinet and the egg and butter places on the refrigerator door as they were removed and the aluminum door replaced with a glass door. This study aims to expand our knowledge about the temperature and flow fields of this refrigerator mo

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Publication Date
Mon Dec 31 2018
Journal Name
International Journal Of English Linguistics
Iraqi EFL Students’ Difficulties in Writing Composition: An Experimental Study (University of Baghdad)
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Iraqi EFL students face difficulties in writing composition, especially academic writing, which affects negatively their exam results. This study has been conducted in the Department of English at College of Education for Women, University of Baghdad, in order to identify first year EFL students&rsquo; incompetence in writing. This may enhance their achievement by some weekly writing activities. It deals with Iraqi EFL students&rsquo; difficulties in writing paragraphs such as descriptive, process, opinion, and factual paragraphs. The study aims to identify these difficulties and to suggest suitable solutions for them. The researcher perceives that it is necessary to enhance students&rsquo; skills in writing because it i

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Publication Date
Sun Mar 04 2018
Journal Name
Journal Of The College Of Education For Women
Novel of (Ya Mariam), for Sinan Antwane : A Pragmatic Study
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Pragmatics looked at literary discourse as an external subject that needed an actor and based on a communicative relationship, that is, it examines literary work by focusing on the author's intent, and attempting to monitor the pilgrim and logical dimension in the text. It focuses on the practical and communicative aspect of the language, which aims to convince the recipient and his or her emotional influence.And the novel (Yamrim) starting from the title (Sos) communication, and building dialogue and pilgrims based on two different logic completely, the logic of optimism and look at things with absolute objectivity, the logic of pessimism and closure and look at things with absolute passion. These two tendencies are embodied by the char

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Publication Date
Thu Apr 01 2021
Journal Name
Journal Of Bridge Engineering
Experimental Investigation of Curved-Soffit RC Bridge Girders Strengthened in Flexure Using CFRP Composites
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