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.
ne,؛Stability constants were determined for complexes of amino acids : L-leuc tryptophane and Aspartic acid with thorium (IV ) and uranyle ( U02++) ions at ؛ serine
The study was conducted to determine the effect Toxoplasma gondii and the efficacy of azithromycin and garlic tablets on the treatment of acute murine toxoplasmosis and observe the histopathological changes due to infection. 60 Albino mice were divided into six groups, and their survival rate, pathology, bioassay trial and immunofluorescence were observed. Results revealed that azithromycin (250 mg/kg/day) given to infected mice increased the survival rate (90% on day 7 PI) and decreased the histopathological changes when compared with the control groups. Garlic tablets (500 mg/kg/day) had lesser effect on infected mice, and the survival rate (40% at days 6 and 7 PI) was lower than the groups treated with azithromycin. The group treated wit
... Show MoreThis paper aimed to investigate the relationship between work stress and cognitive failures among administrators of university professors and included a sample by searching from (474) teachers’ administrators and those who obtaining master degree or doctorate. Work stress scale was used, which is prepared by Amina Boashiri supporting by that, a measure of cognitive failures has also been used which is prepared by Khamis Shaeal Al Badri. In order to obtain the results statistical methods were used including (one-sample t-test, Pearson correlation coefficient) results indicated a high level of stress Work stress and high level of cognitive failures among professors as administrators, and also there is a positive correlation, as well as stat
... Show MoreThe trichomes and chemical composition of three species of the genus Salvia wild-grown (Salvia lanigera, Salvia spinosa) and cultured (Salvia officinalis) were studied in the Anbar governate, the chemical components of the stem and leaves were studied by Gas chromatography–mass spectrometry(GC-MS), in addition to studying the trichomes of the epidermis in the stem and leaves (upper and lower epidermis) by Light microscope. Important differences appeared to us in the chemical study, where it was found that some compounds were found in species without others, which gives them taxonomic importance, also, the trichomes were important in distinguishing the studied species, the species S. spinosa was distinguished by the presence of gla
... Show MoreBackground: obesity is nowadays a pandemic condition. Obese subjects are commonly characterized by musculoskeletal disorders and particularly by non-specific low back pain (LBP). However, the relationship between obesity and LBP remain to date unsupported by an objective measurement of the mechanical behavior of spine and it is morphology in obese subjects. . Objectives: To identify the relationship between obesity and LBP regarding (height, weight, sleeping, chronic diseases, smoking, and steroid). Method: A cross-sectional study was conducted from the first of January 2016 to January 2018 in obe
... Show MorePraise be to God, who created people from one soul, and made her husband, and prayers and peace be upon His Messenger, Mercy given and the grace given, and on a machine and companions pure. Divorce cases have increased in recent years in a worrying manner, especially since divorce has unforeseen consequences at the individual and social levels. The source of concern stems from the fact that the cohesion and integrity of society starts from a family as it is the cornerstone of the social structure, which is the foundation upon which the large society is based. Marital life may suffer from problems and obstacles that are difficult to solve, so the man presents the divorce of his wife and that the phenomenon of divorce is not a result of it, b
... Show MoreThis research aims to study the morphological anatomical characteristics and geographical distribution of the species Horwoodia dicksoniae (Turrill) belong to Brassicaceae family in Iraq. The results were revealed the morphological characteristics of the root, stem, leaves, fruits and seeds, abaxial surface of the leaf characterized by covered with simple hairs. The fruits were circular in shape with wide wing and have one seed. The seeds were conical shape and pustular surface configuration. The anatomical characteristics of the root, stem, and leaf were studied and the cross-section of the root was characterized by thick periderm layer and cortex layer consisting primarily of parenchyma cells, stem cross section was characterize
... Show MoreOscillation criteria are obtained for all solutions of the first-order linear delay differential equations with positive and negative coefficients where we established some sufficient conditions so that every solution of (1.1) oscillate. This paper generalized the results in [11]. Some examples are considered to illustrate our main results.