The perturbed equation of motion can be solved by using many numerical methods. Most of these solutions were inaccurate; the fourth order Adams-Bashforth method is a good numerical integration method, which was used in this research to study the variation of orbital elements under atmospheric drag influence. A satellite in a Low Earth Orbit (LEO), with altitude form perigee = 200 km, was selected during 1300 revolutions (84.23 days) and ASat / MSat value of 5.1 m2/ 900 kg. The equations of converting state vectors into orbital elements were applied. Also, various orbital elements were evaluated and analyzed. The results showed that, for the semi-major axis, eccentricity and inclination have a secular falling discrepancy, Longitude of Ascending Node is periodic, Argument of Perigee has a secular increasing variation, while true anomaly grows linearly from 0 to 360°. Furthermore, all orbital elements, excluding Longitude of Ascending Node, Argument of Perigee, and true anomaly, were more affected by drag than other orbital elements, through their falling as the time passes. The results illustrate a high correlation as compared with literature reviews in this field.
Production of fatty acid esters (biodiesel) from oleic acid and 2-ethylhexanol using sulfated zirconia as solid catalyst for the production of biodiesel was investigated in this work.
The parameters studied were temperature of reaction (100 to 130°C), molar ratio of alcohol to free fatty acid (1:1 to 3:1), concentration of catalyst (0.5 to 3%wt), mixing speed (500 to 900 rpm) and types of sulfated zirconia (i.e modified, commercial, prepared catalyst according to literature and reused catalyst). The results show the best conversion to biodiesel was 97.74% at conditions of 130°C, 3:1, 2wt% and 650 rpm using modified catalyst respectively. Also, modified c
... Show MoreSolar hydrogen line emission has been observed at the frequency of 1.42 GHz (21 cm wavelength) with 3m radio telescope installed inside the University of Baghdad campus. Several measurements related to the sun have been conducted and computed from the radio telescope spectrometer. These measurements cover the solar brightness temperature, antenna temperature, solar radio flux, and the antenna gain of the radio telescope. The results demonstrate that the maximum antenna temperature, solar brightness temperature, and solar flux density are found to be 970 K, 49600K, and 70 SFU respectively. These results show perfect correlation with recent published studies.
Ultimate oil recovery and displacement efficiency at the pore-scale are controlled by the rock wettability thus there is a growing interest in the wetting behaviour of reservoir rocks as production from fractured oil-wet or mixed-wet limestone formations have remained a key challenge. Conventional waterflooding methods are inefficient in such formation due to poor spontaneous imbibition of water into the oil-wet rock capillaries. However, altering the wettability to water-wet could yield recovery of significant amounts of additional oil thus this study investigates the influence of nanoparticles on wettability alteration. The efficiency of various formulated zirconium-oxide (ZrO2) based nanofluids at different nanoparticle concentrations (0
... Show MoreA new method based on the Touchard polynomials (TPs) was presented for the numerical solution of the linear Fredholm integro-differential equation (FIDE) of the first order and second kind with condition. The derivative and integration of the (TPs) were simply obtained. The convergence analysis of the presented method was given and the applicability was proved by some numerical examples. The results obtained in this method are compared with other known results.
This study sought to determine the impact of spreading the culture of quality in improving the quality of tourism service in some hotels in Erbil governorate. The theme of excellence in providing service and attention to it has become the concern of most organizations in general and tourism service organizations in particular. Tourists try to establish the mental status of customers about their tourism organizations had to pay attention to the quality of service provided to the customer and work to develop them to the advanced stages of satisfaction and happiness of customers and this will certainly positively affect the improvement of service in the tourism sector, Of the research variables were examined statistically by distrib
... Show MoreIH Abdul-Abbas, QJ Rashid, M RasimYounus, PalArch's Journal of Archaeology of Egypt/Egyptology, 2021 - Cited by 9
The research aims to study the impact of the dimensions of fun in the workplace in achieving internal marketing And knowing the type of relationships That link the dimensions of fun in the workplace With each other, None of the researchers mentioned (to the researcher's knowledge) the link between fun in the workplace and internal marketing From this point of view the main objective is determined, which is to study the effect of fun in the workplace in internal marketing, The research was conducted at Al Salam Public Company for Communications and Information Technology The research community was represented by (308) employees of the aforementioned company , Where a random sample was selected tha
... Show MoreThe Shiite religious authority in Iraq has played an active and vital role over its long history in promoting values of tolerance, rejecting extremism, advocating unity and confronting external challenges. This role has increased significantly after 2003 as a result of the great challenges that have passed in Iraq. Despite its clear policy of non-interference in political matters, except in cases of necessity, but the great role it played in maintaining national unity and advocating the rejection of extremism and sectarianism has made it a necessary need in Iraq to confront any deviations, dispersions or threats that affect society and the state. Therefore, its role in the process of reform was prominent on the political level by calling
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