Visualization of water flow around different bluff bodies at different Reynolds number ranging (1505 - 2492) was realized by designing and building a test rig which contains an open channel capable to ensure water velocity range (4-8cm/s) in this channel. Hydrogen bubbles generated from the ionized water using DC power supply are visualized by a light source and photographed by a digital camera. Flow pattern around a circular disk of (3.6cm) diameter and (3mm) thickness, a sphere of (3.8cm) diameter and a cylinder of
(3.2cm) diameter and (10cm) length are studied qualitatively. Parameters of the vortex ring generated in the wake region of the disk and the separation angle of water stream lines from the surface of the sphere are plotted versus Reynolds number. Proper empirical formulas are investigated to describe the behavior of vortex ring parameters and separation angle versus Reynolds number. Vortex growth history in the wake region of the cylinder is identified by analyzing the photographs extracted from the digital camera used for
photography purposes. Water velocity measurement in the upstream region and near the edge of the disk is conducted at different Reynolds number by measuring the length of Hydrogen bubble pulse streaks generated in the upstream region of the disk using electronic pulse generator circuit. Special electronic circuit is designed and fabricated to cut off the applied DC voltage. The calibration of the designed pulse generator is conducted using the proper oscilloscope device. The pictures extracted from the digital camera are used for analyzing the generated Hydrogen pulses.
Background: Enterococcus faecalis (E. faecalis) is a prototypical resistant bacterium in root canal infections and a leading cause of endodontic treatment failure. German chamomile (Matricaria chamomilla) flower extract has been used as a traditional medicine to treat infections. The aim of this study was to investigate the antimicrobial efficacy of chamomile extract on the removal of E. faecalis root canal biofilm. Materials and Methods: Chamomile flower extract was prepared and subjected to detailed chemical analysis. For the in vitro biofilm model, human mandibular premolars (n=48) with 18-20mm working length were used. Root canal preparation was performed using the ProTaper® Next system. Each sample was split longitudinally and reassem
... Show MoreThe research aims: to build a measure of the cognitive competence of coaches from the point of view of players of Iraqi Premier League volleyball clubs and extract scores and standard levels for it. In order to achieve the objectives of the research, the descriptive method was used using the survey method. As for the research sample, it was chosen intentionally, and was represented by volleyball players for the Premier League 2024-2025. The sample was divided into exploratory, constructive, and standardizing, and starting the construction procedures, which included finding the scientific foundations for the scale, in addition to extracting the modified standard score and levels for the sample of the main experiment for standardization. Amou
... Show MoreThe importance of social exclusion lies in the psychological problems that cause problems in social relations and mental-physical health. For this reason, the researcher set three goals for the current research: identifying the level of social exclusion among people infected with the Coronavirus. The incubation period of the virus. Social exclusion and its relationship to the duration of incubation of the disease among people infected with the Coronavirus. The result showed that the research sample does not suffer from social exclusion. The mean value for the period from
(8-14) days is the highest value followed by the period (1-7) days and the period
(14 days or more) comes at the end. There is no statistically sig
... Show MoreThe experiment was carried out in the green house of botanical garden belong to Department of Biology/College of Education for Pure Science Ibn AL-Haitham, University of Baghdad for growing season 2017-2018 to evaluate effect of lead stress with concentrations (0, 50, 100, 150) mg.L -1 and Selenium concentrations (0, 15, 30) mg.L-1 on growth of dill plant using pots. The experiment was designed according to completely randomized design (CRD) with three replications. Result indicated that dill plants subjected to lead stress with height concentrations caused decrease in plant parameters (plant height, no. of branches. plant-1, root length, shoot dry weight, the content of nitrogen, phosphorus and potassium, protein concentration, no. of umbe
... Show MoreThe study aimed to reveal the impact of employing the strategy of the talk-ative groups on the achievement and academic tendencies of chemistry forstudents of the fifth grade of applied science for the academic year (2018 -2019), and to achieve this goal the researcher used the experimental methodon the sample of the study consisting of (50) students, prepared achievementtest falls Under (60) paragraphs, and the scale of tendencies for chemistryfalls under (30) paragraphs, and after the researcher completed the researchexperiment according to what was planned:The superiority of the experimental group studied according to the strate-gy of the talkative groups was found in the post-application of the test ofachievement and attitudes of chemis
... Show MoreIn this work, (CdO)1-x (CoO)x thin films were prepared on glass slides by laser-induced plasma using Nd:YAG laser with (λ=1064 nm) and duration (9 ns) at different laser energies (200-500 mJ) with ratio (x=0.5), The influence of laser energy on structural and optical properties has been studied. XRD patterns show the films have a structure of polycrystalline wurtzite. As for AFM tests results for the topography of the surface of the film, where the results showed that the grain size and the average roughness increase with increasing laser energy. The optical properties of all films were also studied and the results showed that the absorption coefficient for within the wavelength range (280-1100 nm), The value of the optical power gap fo
... Show More