Solar photovoltaic (PV) has many environmental benefits and it is considered to be a practical alternative to traditional energy generation. The electrical conversion efficiency of such systems is inherently limited due to the relatively high thermal resistance of the PV components. An approach for intensifying electrical and thermal production of air-type photovoltaic thermal (PVT) systems via applying a combination of fins and surface zigzags was proposed in this paper. This research study aims to apply three performance enhancers: case B, including internal fins; case C, back surface zigzags; and case D, combinations of fins and surface zigzags; whereas the baseline smooth duct represents case A. A 2D, steady-state simulation model that took into account the impact of the convective flow of air circulating inside the PVT system in addition to radiative and convective heat losses from the front PV surface was developed and validated via previous tests. The results revealed that, under the same volume requirements, the application of surface zigzags is preferred for airflow rates of 0.06 kg/s or less, whereas the introduction of fins is preferred for higher airflow rates. The results also revealed that, of the three cases considered, the introduction of the fin–surface zigzag combination is the most effective and has the potential to improve the electrical and thermal efficiency by ~26% and 3%, respectively.
ABSTRACT
The research aim is to determine the relation between governmental consumption expenditure (GCE) & GDP in Iraq for the period 1981-2006.
The research has determined the scale of optimization for (GCE) & try to know the extent productivity of this expenditure and using the long run &short run model to test .The results clarify the following
1-The marginal productivity for the (GCE) is positive so it is productive.
2-The (GCE) in Iraq is too high because the marginal productivity for the expenditure less than 1.
3- The (GCE) percentage to GNP is
... Show MoreThe researcher aims to Diagnose the reality of research variables, strategic leadership and decision support systems, and their impact on crisis management in the General Company for Steel Industries because of their important role in preventing crises and reducing their occurrence for the research company in particular and other companies in general affiliated with the Ministry of Industry and Minerals, as well as clarifying theoretical concepts of research variables As it included the answer to questions related to the research problem, including (Is there an impact of the strategic leadership in managing crises if decision support systems are used), and the researcher adopted the descriptive and analytical approach in its comp
... Show MoreThe current study aimed to reveal the moral values available in the Arabic language textbook (Al-Mu’nes) for grades eleven and twelve for post-basic education in the Sultanate of Oman. The researcher adopted the descriptive approach using the sentence as measuring unit in the analysis process. The five fields of moral values and their subcategories values represented the categories of the analysis. Iterations of values and the percentages of iteration were calculated in those textbooks. Moreover and the analysis and stability of the process were confirmed.
After referring to previous studies, it was possible to de
... Show MoreThe importance of this topic may not be overlooked by many of the specialists, because it is one the sciences of the Arabic language, but it is an important method in the field of influencing the recipient and his aesthetic ability to create influential images as well.
The talking about Semantic (Badi'iyah)is as old as the Arabic age, so it may be talking about it not the new thing because the people who specialized have preceded us and exhausted all the talk .
The effect of compound machine on wheat "Tamuz cultivar" was studied based on some technical indicators which were tested under three practical speed (PS) of 2.015, 3.143, and 4.216 km.hr-1 and three tillage depth (TD) of 11, 13, and 15cm. The split-split plot arrangement in RCBD with three replications was used. The results showed that the PS of 2.015km.hr-1 was major best than other two speed in all studied conditions, physical properties (SBD and TSP), mechanical parameters (FD, (DP and LAS), and yield and growth parameters (PVI, BY and HI). The TD of 11cm was major effect to the other two levels TD of 13 and TD of 15cm in all studied conditions. All interactions were significant,
The radial wave functions of the generalise dWoods–Saxon (GWS) potential within the two-body model of (Core + n) have been used to study the ground-state density distributions of protons, neutrons and matter and the associated root mean square (rms) radii of neutron-rich 14B, 22N, 23O and 24F halo nuclei. The calculated results show that the radial wave functions of the generalised Woods–Saxon potential within the two-body model succeed in reproducing neutron halo in these exotic nuclei. Elastic electron scattering form factors for these nuclei are studied by combining the charge density distributions with the plane-wave Born approximation (PWBA).
The vision and philosophy of the economic system in Iraq after 2003 were not clear-cut because of overlapping internal factors was the novelty of the political system and the lack of political and economic decision makers to understanding and conviction full need shaping a new administration for the Iraqi economy is able to succeed economic development programs, and external factors was determinedly organizations international application of shock reforming style and contrary to the social reality and the security which reflected negatively on the work and consistency Lisseeash financial balance between stability and growth and raise the level of consumer spending and the importance of research lies in the ability of fiscal policy to achie
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