The present work presents design and implementation of an automated two-axis solar tracking system using local materials with minimum cost, light weight and reliable structure. The tracking system consists of two parts, mechanical units (fixed and moving parts) and control units (four LDR sensors and Arduino UNO microcontroller to control two DC servomotors). The tracking system was fitted and assembled together with a parabolic trough solar concentrator (PTSC) system to move it according to information come from the sensors so as to keep the PTSC always perpendicular to sun rays. The experimental tests have been done on the PTSC system to investigate its thermal performance in two cases, with tracking system (case 1) and without tracking system (case 2). The experimental results showed that the average solar radiation falling on the PTSC prototype in the two cases during the same time was 854 and 701 watt/m2, respectively, which means an increase in the solar radiation about 21.8 % when using tracking system. It was found that the average useful heat gain output of solar collector was equal to (376.2, 252.6 watt) for the two cases, respectively, so there was an increase of about 48.9 % when using the tracking system. Also, the average thermal efficiency of the PTSC was found to be (20.7, 26.5 %) for the two cases, respectively, which means an increase in the average efficiency by 28% with use of tracking system compared to the fixed case.
Polycyclicacetal was prepared from the reaction of PEG with aldehyde derived from Erythro-ascorbic acid (pentulosono-ɣ-lactone-2,3-enedianisoate).All these compounds were characterized by Thin Layer Chromatography (TLC) and FTIR spectra and aldehyde was also characterized by (U.V-Vis), 1HNMR, 13CNMR, and mass spectra.The inhibitory effect of prepared polymer on the activity of human serum AcetylCholinesterase has been studied in vitro. The polymer showed a remarkable activity at low concentration (4.7x10-3 – 4.7x10-8M).
This study aimed to study the effect of Ziziphus spina christi Aqueous cold and Alcoholic leaves and fruits extracts on the growth and activities of the following types of bacteria :( Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pyogenes ). The results appeared outweigh the alcoholic extract of leaves and fruits of Sidr that prepared by saxholate extractor by addition of ethanol 95% significant superiority as compared with aqueous extract that prepared by using distilled water as was its influence inhibitor to the growth and effectiveness of bacteria , about the treatment of in-vivo to cause injury to these types of bacteria diagnosed laboratory mice and treated with alcoholic extract of the leaves o
... Show MoreMixed ligand metal complexes are synthesized from oxalic acid with Schiff base, and the Schiff base was obtained from trimethoprim and acetylacetone. The synthesized complexes were of the type [M(L1)(L2)], where the metal, M, is Ni(II), Cu(II), Cr(III), and Zn(II), L1 corresponds to the trimethoprim ((Z)-4-((4-amino-5-(3,4,5- trimethoxybenzyl)pyrimidine-2-yl)imino)pentane-2-one) as the first ligand and L2 represent the oxalate anion (𝐶𝑂 ) as a second ligand. Characterization of the prepared compounds was performed by elemental analysis, molar conductivity, magnetic measurements, 1H-NMR, 13C-NMR, FT-IR, and Ultraviolet-visible (UV-Vis) spectral studies. The recorded infrared data is reinforced with density functional th
... Show MoreBackground: Chief complaint of patients attending dental clinic represents the first step towards treatment plan. However, most of patients are not aware but the extent and severity of periodontal disease, which could be also, misdiagnose by the dentist. Aim of the study: To investigate whether reported chief complaint(s) are consistent with oral hygiene status Materials and methods: Records of 1102 patients, attending periodontics clinics in the college of dentistry/ university of Baghdad, were used to determine ten most commonly reported chief complaints. Sample of patients was further subdivided according to gender and age. In addition, plaque and gingival index were recorded to determine oral hygiene status. Results: Patients mostly
... Show MoreEvery researcher must say that the world in continually progress toward the best and that
the Arab and Islamic civilization had produced much of systems and virtuous educational
practices which raised from Islamic heritage. This nation was not isolated from external
world, but it was made a clear active for promote the banner of other nations which entered
under her influence to promote Islamic banner and Muslims. Consequently also Muslims are
affected and influenced, this resulted a clear impact in the civilization and educational
ideology especially in the contemporary teaching methods.
The research deals with the concept of rationalization of consumption, which is legitimately legitimized, by indicating the permissibility of consumption and its limits in Islam, the legitimate aspects of spending and its controls, and the concept of development in the Islamic economy. The researcher followed the descriptive method by presenting the legal texts and jurisprudential opinions and linking them to contemporary economic problems.The research has reached several conclusions, the most important of which is that the goal of Islam in relation to consumption is to inform the Muslim of the amount of economic maturity, and the truth of alms is good in money and religion. It is necessary for achieving maturity that both means
... Show MoreThe study aims at measuring the dimensions of binding and non-binding social responsibility and its relation to the organizational performance in telecommunication companies in the Republic of Yemen using analytical descriptive approach and questionnaire as a main tool for data collection and comprehensive inventory method.
It has been found that there is a positive effect and significant moral relation between social responsibility with its binding and non-binding dimensions and the organizational performance of telecommunication companies in the Republic of Yemen at a level of significance below (0.05). It has also been found that the correlation between the non-binding social responsibilit
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تدور الدراسة في علم الاقتصاد المنزلي حول احتیاجات الانسان الضروریة لاستمرار الحیاة ومواقف في محیط
الاسرة وتفاعل مع ظروف البیئة المحیطة بھ .والتي تكون دائمة التغییر لذلك یمكن تعریف علوم وفنون الاقتصاد
المنزلي وفنونھ انھا عبارة عن مجموعة منظمة من المعارف والعلوم تتركز في محور الاسرة والمنزل حیث ینمو
ویتطور الانسان بالعلاقات الانسانیة والنواحي الاقتصادیة والاجتماعیة من جھة والنواحي العلمیة وا
In this paper, a polymer-based composite material was prepared by hand Lay-up method consisting of epoxy resin as a base material reinforced by magnesium oxide powder once and silicon dioxide powder again and with different weight ratios (3, 6, 9 and 12) wt %. The three-point bending test was performed in normal conditions and after immersion in sulfuric acid. The results showed that the bending value decreased with the increase of the weighted ratio of the reinforcement material (MgO, SiO2). The Bending of samples reinforced by SiO2 was found to be less than the bending of samples reinforced by particles (MgO). For example, the bending of the SiO2 sample (0.32 mm) at the weighted ratio (3%) and for the MgO (0.18mm) sample at the weight
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