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.
Abstract
The aim of the research is to identify the role of ethical leadership in achieving comprehensive quality standards in public education schools in the Al-Ardha governorate. To achieve this goal, the descriptive approach was used, the researcher developed a questionnaire consisting of (35) items, divided into two sections: the first one is related to ethical leadership includes (17) items, and the second section relates to total quality management includes (18) items. The research sample consisted of (405) teachers from the stages of public education. The results showed that the level of ethical leadership practice (ethical personal characteristics, ethical administrative features, teamwork, and human rela
... Show MoreThe technology and modern social communication medias have contributed to changing many of our concepts about education to a large extent; these technological advancements have created new challenges for the Instructor of course, but on the other hand it did provided him with expressive media, models and strategies that the old methods cannot fulfill, including the flipped classroom strategy, which is one of the modern technical solutions and in it's optimal use it can correct the weakness of the traditional education and can develop the communication skills as a whole among the students, in order to create a positive, active and interactive student.
The current research contained - four chapters: the first one included the methodolog
This research reveals the treatment mechanisms followed in the media for covering the topic of displacement and captivity of Yazidi in the Iraqi press, through studying all the publishing in one of the Iraqi newspapers concerning the research subject. The research problem is in the following questions:
- What are the journalistic arts that are tackled by the newspaper concerning the subject of the Yazidi women?
- What are the editing forms for the model of the press subjects that have been employed about the event and what are its sources?
- What are the highlighting means used in presenting the subjects within the journalistic arts?
- What are the i
Iraqi economy has grown rapidly. Iraqi citizen, therefore, should be very much involved with the comprehensive development after his long patience. Such development should begin with him and his family to get the housing commodity, which is indeed not a cheap one.
In this regard, the Iraqi legislator drew attention to the necessity of issuing housing finan
... Show MoreBackground:
Multiple sclerosis is a chronic disease believed to be the result of autoimmune disorders of the central nervous system, characterised by inflammation, demyelination, and axonal transection, affecting primarily young adults. Disease modifying therapies have become widely used, and the rapid development of these drugs highlighted the need to update our knowledge on their short- and long-term safety profile.
Objective:
The study aim is to evaluate the impact of disease-modifying treatments on thyroid functions and thyroid autoantibodies with subsequent effects on the outcome of the disease.
Materials and Methods:
A retro prospective study
... Show MoreAA Noaimi, BM Fadheel, Saudi medical journal, 2008 - Cited by 25
<span lang="EN-US">The fundamental of a downlink massive multiple-input multiple-output (MIMO) energy- issue efficiency strategy is known as minimum mean squared error (MMSE) implementation degrades the performance of a downlink massive MIMO energy-efficiency scheme, so some improvements are adding for this precoding scheme to improve its workthat is called our proposal solution as a proposed improved MMSE precoder (PIMP). The energy efficiency (EE) study has also taken into mind drastically lowering radiated power while maintaining high throughput and minimizing interference issues. We further find the tradeoff between spectral efficiency (SE) and EE although they coincide at the beginning but later their interests become con
... Show MoreThe research aimed at designing a teaching aid for learning backswing into handstand as well as identifying its effect on learning skill performance. The researchers hypothesized statistical differences between pre and post-tests in favor of the research group. They used the experimental method on six (13 – 16) year–old Baghdad club gymnasts. The researchers used the one group design in which all players perform pretests followed by special tests on the teaching aid than are tested posttests. The researchers conclude that the teaching aid positively affected learning the skill as well as the teaching aid was very good and endured the performance of all gymnasts. The researcher recommended making simi
... Show MoreThis study investigates the possibility of removing ciprofloxacin (CIP) using three types of adsorbent based on green-prepared iron nanoparticles (Fe.NPs), copper nanoparticles (Cu. NPS), and silver nanoparticles (Ag. NPS) from synthesized aqueous solution. They were characterized using different analysis methods. According to the characterization findings, each prepared NPs has the shape of a sphere and with ranges in sizes from of 85, 47, and 32 nanometers and a surface area of 2.1913, 1.6562, and 1.2387 m2/g for Fe.NPs, Cu.NPs and Ag.NPs, respectively. The effects of various parameters such as pH, initial CIP concentration, temperature, NPs dosage, and time on CIP removal were investigated through batch experiments. The res
... Show More