The design, construction and investigation of experimental study of two compound parabolic concentrators (CPCs) with tubular absorber have been presented. The performance of CPCs have been evaluated by using outdoor experimental measurements including the instantaneous thermal efficiency. The two CPCs are tested instantly by holding them on a common structure. Many tests are conducted in the present work by truncating one of them in three different levels. For each truncation the acceptance half angle (θc) was changed. Geometrically, the acceptance half angle for standard CPC is (26o). For the truncation levels for the other CPC 1, 2 and 3 the acceptance half angle were 20o, 26o and 59o, consequently. A significant difference between the instantaneous thermal efficiency of 3.86× CPC (θc=20o) and 2.32× CPC (θc=26o), and between that for 3.61× CPC (θc=26o) and 2.32× CPC (θc=26o). It's noticed that the difference between the instantaneous thermal efficiency of 2.32× CPC (θc=59o) and 2.32× CPC (θc=26o) is small compared with the difference of the first and second cases, the instantaneous thermal efficiency of 2.32× CPC (26o) was higher than those for other three CPCs. The experimental results show that the maximum thermal efficiency of the full 2.32×CPC (26o) is 0.708, the maximum thermal efficiency of the 3.93×CPC (15o), when it's truncated to 3.84× CPC (20o), 3.61× CPC (26o) and 2.32× CPC (59o) are 0.51, 0.52 and 0.66, respectively. As the concentration ratio decreases from (3.93× to 1×), the thermal efficiency, energy losses and optical efficiency increase from (0.47 to 63), (1.58 to 7.2 K.m2/W) and (0.494 to 0.797), respectively.
This research is based on the descriptive and analytical methodology. The importance of studying labor laws and labor unions in Japan between 1889 and 1946 constitutions is because Japan was out of a feudal phase, and had no idea about the factory system and industrialization in their modern sense before the Meiji era. Generally, its labor system used to be mostly familial, and the economic system was based on agriculture. This called for the enactment of legislations and laws appropriate for the coming phase in Meiji era. Thus, this paper examines the role of Meiji government in enacting labor legislations and laws when he came to power in 1896, and his new constitution in 1889 and the civil code of 1896. It further examines the way Mei
... Show More
Many biological tests were done to study the effect of the crude alcoholic leaves extracts on the biological characteristics at the larvae fruit fly Ceratitis capitata with different concentrations of the extracts exposed 1,2,3,5 and 7.5 % at constant laboratory conditions includes the temperature and the relative humidity (27±2C0&70±5 % respectively). The results of the experiments showed that the alcoholic extracts of the plant effected the growth and the development of the larvae and pupae according to the concentrations . The alcoholic extracts proved to have the highest mortality tend to 66.76 % in larva treated with alcoholic at concentration 7.5 % the
... Show More
The research entitled "the attitudes of Iraqi People towards the Logic Propaganda for Terrorist Organization such as Daash Regulation, as-Qaida, and Jabhat al-Nasra". It is a field study on the professors and the students of the College of Mass Media at Baghdad University in 2014.
After the global war on terrorism declared on September 11, 2011, the researcher finds it is important to study such subject as it threats the unity and sovereignty of Iraq especially after th
... Show More
The rivers are the main source of fresh water for many countries and the great development which is considered as one of the sustainable development elements in its various agricultural, industrial, domestic and environmental fields .The countries of the world seek food security and water security in order to ensure the basic needs of citizens .Because their distribution is uneven in many regions of the world with different human needs, which leads to conflicts over water sources, especially those located in one international river basin .This has led to the emergence of internationallegal rules governing the management of The problem revolves around the dialectic between limited water resources and increased need for water use b
... Show More
Brainstorming is one of the fundamental and necessary concepts for practicing the auditing profession, as auditing standards encouraged the implementation of brainstorming sessions to reach reasonable assurance about the validity of the evidence and information obtained by the auditor to detect fraud, as the implementation of brainstorming sessions and the practice of professional suspicion during the audit process lead to increase the quality of auditing and thus raise the financial community's confidence in the auditing profession again after it was exposed to several crises that led to the financial community losing confidence in the auditing profession.
The research aims to explain the effect of brain
... Show More
Brainstorming is one of the fundamental and necessary concepts for practising the auditing profession, as auditing standards encouraged the implementation of brainstorming sessions to reach reasonable assurance about the validity of the evidence and information obtained by the auditor to detect fraud, as the implementation of brainstorming sessions and the practice of professional suspicion during the audit process lead To increase the quality of auditing and thus raise the financial community's confidence in the auditing profession again after it was exposed to several crises that led to the financial community losing confidence in the auditing profession.
The research aims to explain the effect of brain
... Show More
There are Islamic sources and books that deal with the different doctrinal and differential framework of the Islamic religion with a monistic approach, describing them with embarrassing jurisprudential titles such as: excommunication and expiation, and epithets that carry the characteristics of hatred and rejection, in addition to removing them from the sect and religion, and the reason for that is that the doctrine (A) or (b) considers itself the doctrine that represents only the Islamic religion, and other doctrines are misguided and disbelieving. the reasons behind this - besides the attempt to establish doctrinal and fiqih rooting in claiming truth and escaping from within the foundational differential doctrinal system – is the pol
... Show More
The importance of the research lies in preparing exercises using a proposed device to learn the skill of thehuman wheel on a machine rug of ground movements of the artistic gymnastics. As for the research problem:Through the presence of the two researchers as teachers and observers of this sport in the gymnastics hall,they noticed that there is difficulty in the students’ performance of the skill of the round off on the machineof the mat of ground movements, according to the researchers’ opinion, the reason for this is that skillsare taught with the limited availability of assistive devices, as well as the lack of use of these devices inexercises according to biomechanical variables, although they facilitate the learning process
... Show More
unacceptable social behaviors, particularly withdrawal behavior that appears in children with autism represent a major problem hindering the process of communication with those around them and therefore the process of mergence with them be difficult.
The withdrawal causes a real affect deficit for children with autism limits the possibility of development of their intellectual and mental growth due to their solitude and the weakness of their focus in the acquisition of pedagogical skills and lack the necessary social skills to maintain the relations of friendship and enjoyment of them.
withdrawal children fail to participate
... Show More