Experimental and numerical investigations of the centrifugal pump performance at non-cavitating and cavitating flow conditions were carried out in the present study. Experiments were performed by applying a vacuum to a closed-loop system to investigate the effects of the net positive suction head available (NPSHa), flow rate, water temperature and pump speed on the centrifugal pump performance. Accordingly, many of the important parameters concerning cavitation phenomenon were calculated. Also, the noise which is accompanied by cavitation was measured. Numerical analysis was implemented for two phase flow (the water and its vapor) using a 2-D simulation by ANSYS FLUENT software to investigate the internal flow of centrifugal pump under cavitating conditions. It was observed that with decreasing NPSHa, the values of the pump head, flow rate and efficiency initially remain constant, but with further reduction in NPSHa these parameters will decrease. Also, it was found that at 3% head drop the percentage drop of the flow rate is less than 2% whereas the percentage drop of the efficiency is greater than 3%. Numerically, it was noticed that the cavitation regions appear at the leading edge of suction side of the impeller blades which represents the lowest pressure area inside the computational domain of the centrifugal pump.
Take the teacher's key position in the educational system as a foundation stone and primarily responsible for achieving the goals of Education , and efficient teacher conscious is the teacher who prepared educationally and specialized training well add to the enjoyment of a range of features that enable them to adjust and compatibility with educational developments
Hence the problem of the study questioning the Kindergarten Does teacher professional awareness that enable it to perform its work learned from experienceThe research sought to measure
1-Professional awareness among teacher Kindergarten
2-Professional awareness of Kindergarten parameters depending on the type of kindergarten.
Limited search parameters Riyadh govern
MWCNTs and hybrid nanocomposite ZnO/Se/MWCNTs have been prepared via Solvothermal technique using Parr reactor at the temperature 180°C and SeCl2 as a catalyst. The obtained MWCNTs and ZnO/Se/MWCNTs are investigated using the FE-SEM, XRD, UV-VIS Spectroscopy and Z-Scan. The novelty of this research is studying the nonlinear optical properties for these prepared materials and the results exhibit that the thickness of the deposited film for hybrid nanocomposite ZnO/Se/MWCNTs is increased, which in turn, increase the nonlinear phase shift of the laser beam compared with the MWCNTs.
Idioms are a very important part of the English language: you are told that if you want to go far (succeed) you should pull your socks up (make a serious effort to improve your behaviour, the quality of your work, etc.) and use your grey matter (brain).1 Learning and translating idioms have always been very difficult for foreign language learners. The present paper explores some of the reasons why English idiomatic expressions are difficult to learn and translate. It is not the aim of this paper to attempt a comprehensive survey of the vast amount of material that has appeared on idioms in Adams and Kuder (1984), Alexander (1984), Dixon (1983), Kirkpatrick (2001), Langlotz (2006), McCarthy and O'Dell (2002), and Wray (2002), among others
... Show MoreThis study aims to illustrate and compare the perspectives of Ibn Sahnun and al-Kabasi about educational system. To this end, the researcher adopted the inductive-analytical approach to analyze their educational perspectives. The study included two chapters: one to give an overview of the life of Ibn Sahnun and al-Kabasi and the other to analyze their perspectives. The findings revealed Ibn Sahnun and al-Kabasi confirmed that compliance with the Islamic rules is an essential condition over all aspects. As for Ibn Sahnun pointed out to the important of teaching Quran as a basic reference and guide of Muslim daily-life skills and behaviors. On the other hand, al-Kabasi focused on the creation and religion as two-main aspe
... Show MoreCollapsible soil has a metastable structure that experiences a large reduction in volume or collapse when wetting. The characteristics of collapsible soil contribute to different problems for infrastructures constructed on its such as cracks and excessive settlement found in buildings, railways channels, bridges, and roads. This paper aims to provide an art review on collapse soil behavior all over the world, type of collapse soil, identification of collapse potential, and factors that affect collapsibility soil. As urban grow in several parts of the world, the collapsible soil will have more get to the water. As a result, there will be an increase in the number of wetting collapse problems, so it's very important to com
... Show MoreDiscotic liquid crystal compounds were synthesized and characterized. Liquid crystalline texture of these compounds was investigated by polarized optical microscopy (POM). The Hartree-Fock approximation (HF) was used to calculate theoretical molecular parameters for synthesized compounds such as optimization, hardness, EHOMO, ELUMO, and energy gap using the Gaussian 09W program.
Job stress is considered one of the most important obstacles that may appear in the work field. In order to deal with the obstacles and challenges , the idea to deal with job stress has come to address job stress as one of the most important trends that enable organizations to face those challenges through focusing on the role of job stress and the organizational climate of the organization.
The research deals with two variables: the job stress as an independent variable, and the organizational climate as a dependent one. Each variable includes five sub-dimensions. These dimensions have been involved in an interaction to form
... Show MoreThe main aim of this research study is to point out the vital importance of high-quality exterior audits to limit discretionary accounting, as it could distort a company’s commercial results. The research introduces a well-founded hypothesis on the preventive powers of high-quality audits, as it can act as a strong exterior control. The research focuses on testing the complex relationship between earnings management and investors’ behavior within the public-listed companies from the food industry. The research gathers credible annual comprehensive data from thirty-five publicly-listed firms from the United States. It encompasses the twenty years prior to 2024, as it includes the twenty years prior to 2024. Additionally, the gathered dat
... Show MoreSoil invertebrates community an important role as part of essential food chain and responsible for the decomposition in the soil, helps soil aeration , nutrients recycling and increase agricultural production by providing the essential elements necessary for photosynthesis and energy flow in ecosystems.The aim of the present study was to investigate the soil invertebrates community in one of the date palms plantation in Aljaderia district South of Baghdad, , and their relationships with some physical and chemical properties of the soil , as Five randomly distributed replicates of soil samples were collected monthly. Invertebrates samples were sorted from the soil with two methods, direct method to isolate large invertebrates and indirec
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