In this work, the effect of vortex shedding on the solar collector performance of the parabolic trough solar collector (PTSC) was estimated experimentally. The effect of structure oscillations due to wind vortex shedding on solar collector performance degradation was estimated. The performance of PTSC is evaluated by using the useful heat gain and the thermal instantaneous efficiency. Experimental work to simulate the vortex shedding excitation was done. The useful heat gain and the thermal efficiency of the parabolic trough collector were calculated from experimental measurements with and without vortex loading. The prototype of the collector was fabricated for this purpose. The effect of vortex shedding at different operation conditions was examined. The variation of angles of attack and wind velocity leads to different values of vortex loading coefficients and shedding frequencies. The relation between the dynamic characteristics and solar collector performance was evaluated. The finite element method was used to estimate the dynamic characteristic of the solar collector in addition to experimental work to evaluate the relation between the dynamic behavior of the collector and its performance.
This study aimed to provide a conceptual model for the use and benefits of the e-Government as related to administrative fraud and financial corruption. The study also looked into their concepts, forms, dimensions and types and the role of e-Government on fraud reduction, corruption in administration and finance and its impact on the government performance. From the result, it is revealed that there is need for electronic government for implementation in order to curb the rate of fraud and administrative and financial corruption and improve the quality of service provision for better performance
Metal oxide nanoparticles demonstrate uniqueness in various technical applications due to their suitable physiochemical properties. In particular, yttrium oxide nanoparticle(Y2O3NPs) is familiar for technical applications because of its higher dielectric constant and thermal stability. It is widely used as a host material for a variety of rare-earth dopants, biological imaging, and photodynamic therapies. In this investigation, yttrium oxide nanoparticles (Y2O3NPs) was used as an ecofriendly corrosion inhibitor through the use of scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), UV-Visible spectroscopy, X-ray diffraction (XRD), and energy dispersive X-ray spe
... Show MoreThis study includes adding chemicals to gypseous soil to improve its collapse characteristics. The collapse behavior of gypseous soil brought from the north of Iraq (Salah El-Deen governorate) with a gypsum content of 59% was investigated using five types of additions (cement dust, powder sodium meta-silicate, powder activated carbon, sodium silicate solution, and granular activated carbon). The soil was mixed by weight with cement dust (10, 20, and 30%), powder sodium meta-silicate (6%), powder activated carbon (10%), sodium silicate solution (3, 6, and 9%), and granular activated carbon (5, 10, and 15%). The collapse potential is reduced by 86, 71, 43, 37, and 35% when 30% cement dust, 6% powder sodium meta-silicate, 10% powder activated
... Show MoreThe research aims at identify the role of the electronic trading system used in the Iraq stock exchange to promote trading activity for the stocks of listed companies in this market.
To prove the hypothesis of research, it was selected the main trading indicators for the market to be a main field in test the research hypothesis.it was selected as the period of time for (9)years span between the years (2005-2013) because they represent the first two articles of equal time periods represent aperiod that preceded the introduction of electronic trading system while the second represents the period of time that followed
The research found a number of conclusions but the mo
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The nanocompsite of alumina (Al2O3) produced a number of beneficial effects in alloys. There is increasing in resistance of materials to surface related failures , such as the mechanical properties , fatigue and stress corrosion cracking .The experimental results observed that the adding of reinforced nanomaterials type Al2O3 enhanced the HB hardness, UTS, 0.2 YS and ductility of 2014 Al/Al2O3 nano composites . the analysis of experiments, indicated that The maximum enhancement was observed at 0.4 wt.% Al2O3. The ultimate improvement percentage were 15.78% HB hardness, 18.1% (UTS), 12.86% (
... Show MoreIn subterranean coal seam gas (CSG) reservoirs, massive amounts of small-sized coal fines are released during the production and development stages, especially during hydraulic fracturing stimulation. These coal fines inevitably cause mechanical pump failure and permeability damage due to aggregation and subsequent pore-throat blockage. This aggregation behavior is thus of key importance in CSG production and needs to be minimized. Consequently, such coal fines dispersions need to be stabilized, which can be achieved by the formulation of improved fracturing fluids. Here, we thus systematically investigated the effectiveness of two additives (ethanol, 0.5 wt % and SDBS, 0.001 and 0.01 wt %) on dispersion stability for a wide range of condit
... Show MoreThis study aims to study the political caricature and its indications in the Palestinian newspapers, to know its subjects, the active characters, the artistic styles, and the symbols the caricaturists use.
The study concluded that there is a variety of subjects that the political caricature handled in the studied newspapers and the degree of interest in every subject. The subjects related to the international subjects came first (% 24.5) and the other subjects came next (% 22.2).
The results showed the caricaturists relied on unnamed symbolic active characters that came first (% 62.3) and named symbolic characters (% 11.1). The positive characteristics of the Palestinian figures were higher than the negative ones, and the
... Show MoreThis study aims to evaluate the performance of emergency departments according to international standards through studying the performance in some of Iraqi public hospitals, where the evaluation performance is considered one of the important topics that take a great deal of officials' attention, especially decision makers in health organizations.
The researcher has derived the research idea from the importance of work in emergency department in hospitals and to what it provides of medical services and quick and immediate nursing care that help in patients' lifesaving, and it is the mirror that reflects the real image for the hospital
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