The thermal and electrical performance of different designs of air based hybrid photovoltaic/thermal collectors is investigated experimentally and theoretically. The circulating air is used to cool PV panels and to collect the absorbed energy to improve their performance. Four different collectors have been designed, manufactured and instrumented namely; double PV panels without cooling (model I), single duct double pass collector (model II), double duct single pass (model III), and single duct single pass (model IV) . Each collector consists of: channel duct, glass cover, axial fan to circulate air and two PV panel in parallel connection. The temperature of the upper and lower surfaces of PV panels, air temperature, air flow rate, air pressure drop, wind speed, solar radiation and ambient temperature were measured. The power produced by solar cells is measured also. A theoretical model has been developed for the collector model IV based on energy balance principle. The prediction of the thermal and hydraulic performance was obtained for the fourth model of PV/T collector by developing a Matlab computer program to solve the numerical model. The experimental results show that the combined efficiency of model III is higher than that of models II and IV. The pressure drop of model III is less than that of models I and IV, by (43.67% and 49%). The average percentage error between the theoretical and experimental results was 9.67%.
The importance of news broadcasts in society has increased after the domination of television over the mass media, especially after emerging the satellite channels, and spreading the satellite dishes among the public at large.
As well as the great role played by the modern technology in the transmission of news and events happening at once. Such role has contributed, significantly, in changing the concept and values of the news. The live broadcast of the events filmed is the news itself.
In the midst of the great transformations and circumstances that Iraq went through after 2003, which witnessed political and security instability, and the large increase in the number of media, especially satellite channels, in Iraq
... Show MoreThe child spends several hours watching animated films, which affect their behavior negatively and positively. This calls parents to monitor what their children are watching, to show them the serious risks of some violent films, and to direct them toward choosing both positive and educational programs that develop their positive behavior. This study aimed to explore the positive and negative effects of watching animation films as well as to identify the role animation films in increasing the cognitive knowledge of kindergarteners. To do this, the descriptive and analytical methods were used. A questionnaire was adopted as a tool for data collection. A scale of (45) items classified into three categories was applied on the r
... Show MoreScientists are investigating the efficacy of different biosorbents for promoting economic and environmental viability in purifying contaminants. Among the primary by-products of biodiesel production is waste microalgae biomass, which has the potential to be used as a cheap biosorbent for the treatment of pollution. In the present study, the biomass left over after extracting the chlorella vulgaris was used to test the potential biosorption of CIP from simulated aqueous solutions. Bisorbent's ability was characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). Analysis with a Fourier Transform Infrared Spectrometer revealed that C
... Show MoreThe current research aims to identify the multiple intelligences in the fourth students’ acquisition of the literary processes of Arabic grammar and to identify the differences in multiple intelligence according to gender (males - females). The study was determined for students of the fourth literary preparatory Al-Hakim Preparatory (for males) and Rabat Preparatory (for females) of the Second Karkh Education Directorate, topics from the Arabic grammar subject (past tense, present tense, imperative, subject, and object) for the first semester of the academic year 2019-2020. The results showed that there were no statistically significant differences at the significance level (0.05) between the average scores of the students who were tau
... Show MoreThe subject of children's rights in the modern era of the priorities of educators , because the child in the community is the future , which is held by the hope which is the basis for society in the renaissance and progress so quickly communities to prove these rights through its various institutions and issued legislation and held numerous conferences and taking specialists the field of childhood Aatron aspects of this rights and Aasalunha including a benefit for children until tomorrow for the rights of children , psychological and social health and educational . Therefore, the current study focused on the awareness of parents and educators of children's rights as individuals most closely satisfying their needs and rights. The
... Show MoreAlO-doped ZnO nanocrystalline thin films from with nano crystallite size in the range (19-15 nm) were fabricated by pulsed laser deposition technique. The reduction of crystallite size by increasing of doping ratio shift the bandgap to IR region the optical band gap decreases in a consistent manner, from 3.21to 2.1 eV by increasing AlO doping ratio from 0 to 7wt% but then returns to grow up to 3.21 eV by a further increase the doping ratio. The bandgap increment obtained for 9% AlO dopant concentration can be clarified in terms of the Burstein–Moss effect whereas the aluminum donor atom increased the carrier's concentration which in turn shifts the Fermi level and widened the bandgap (blue-shift). The engineering of the bandgap by low
... Show MoreThe research topic dealt with the strategic recovery of the insurance service, which is one of the approaches that have an important role in providing solutions and remedies for the recession that affects companies and hinders them from achieving their strategic goals. The research also addressed the strategic objectives of the company as the rationale and actual guide for companies of all activities in order to protect their systems from deviation for its desired purpose. So the aim of the research is to demonstrate the repercussions of the strategic recovery of the insurance Service represented by (compensation, speed of response, apology, initiative (identifying the problem). The company's strategic goals are represented (prof
... Show MoreThe goal of the study is to discover the best model for forecasting the exchange rate of the US dollar against the Iraqi dinar by analyzing time series using the Box Jenkis approach, which is one of the most significant subjects in the statistical sciences employed in the analysis. The exchange rate of the dollar is considered one of the most important determinants of the relative level of the health of the country's economy. It is considered the most watched, analyzed and manipulated measure by the government. There are factors affecting in determining the exchange rate, the most important of which are the amount of money, interest rate and local inflation global balance of payments. The data for the research that represents the exchange r
... Show MoreThe contemporary art culture is considered a resultant of preceding human civilizations from the early days. At the same time, it got closer to the local privacy, because the contemporary Iraqi potter worked hard to create new art, refusing to base his art on the early works, creating art pieces that contains properties to inherited art and their form significance, in order to create a new identity of his own, bringing an empowerment to his deepened civilization, with the goal to create national identity ideas from one hand, and entity and locality from another. Europeans also followed the direction of our civilization, such as (Picasso, Henry Moore, Barbra Hurth, Brankouzi, Hans Arp,..etc). From this point of view comes the importance o
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