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alkej-347
Experimental and Numerical Research on Flow-Induced Vibration in Valves
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Abstract  

All central air conditioning systems contain piping system with various components, sizes, material, and layouts. If such systems in operating mode, the flow in piping system and its component such as valves can produce severe vibration due to some flow phenomenon’s. In this research, experimental measurements and numerical simulation are used to study the flow-induced vibration in valves. Computational fluid dynamics (CFD) concepts are included with one-way and two-way fluid-structure interaction concepts by using finite element software Package (ANSYS 14.57). Detection analysis is performed on flow characteristics under operation conditions and relations with structural vibration. Most of real geometrical, operational, and boundary conditions are simulated to obtain best similarity with real operation conditions. Comparisons performed between experimental data and numerical results (one-way and two-way simulation) to verify the results. The main conclusion was drawn from the study that the dominant source of vibration for valve is the water pulsation in addition to amount of water hammering. In addition, the main source of water pulsation in globe valve is the vortex shedding and pressure difference between upstream and downstream of valve. The vibration amplitude was increased with increasing flow rate until to be maximum when the flow rate around 30% and then decreased until flow rate reaches to around 85% and then trends to be constant.

Keywords: Flow-induced vibration, vortex shedding, pressure pulsation, valve, finite element, ANSYS, fast Fourier transform (FFT).

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Publication Date
Fri Dec 16 2022
Journal Name
Journal Of The College Of Languages (jcl)
The official business style of the Russian literary language. Problems of formation.: Официально-деловой стиль русского литературного языка. Проблематика формирования.
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In the article we consider features of official style, its functions and factors which influence the definition of the style. The topicality of the issue can be explained by rapid development of market economy which affects in its turn business correspondence. In this regard, there are a lot of cliché, terms and professionalisms appeared recently. Only correct usage of them can serve as a key to successful communication in Russian as well as other languages. This work highlights documents that are part of the diplomatic style such as declarations, credentials, notes, resolutions and other documents. The administrative style can include orders and instructions.

Аннотация.

 В данной статье рассмо

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Publication Date
Sun Feb 10 2019
Journal Name
Journal Of The College Of Education For Women
دور اﻟﺘﻐﺬﯾﺔ ﻓﻲ ﻣﺮﺣﻠﺔ اﻟﻄﻔﻮﻟﺔ اﻟﻤﺒﻜﺮة (3- 5 سنوات ( وبعض المتغيرات ودورها في اصابة الاطفال بتسوس الاسنان
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Teeth decay is one of the distinctive diseases which infects the children of generation .though it is not adeacly disease, it leads to huge problems , especially if it is infect children in their early childhood .There are many factors which lead to this disease , and to achieve the goal of this research in trying to stop the most important nutrition factors and others reasons that have relation with this disease .The practical application has been done for four months on children , who have been chosen randomly of the age ( 3-5 years) of both sexes , infected with teeth decay , from Baghdad city ( al karkh and al rusafa ) , the number of children reached to 90 child , divided into tow groups 45 male , and( 45 )female .Again they have be

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Publication Date
Tue Nov 13 2018
Journal Name
Arab Science Heritage Journal
الثروة الثروة المائية في المغرب العربي من القرن 4 – 7 هـ/ 10 م – 13 م دراسة تاريخية
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Water resources would be differentiate in Morocco specially in Morocco  which appear as form of eyes ,rivers as dissolved water of mountain.

The human takes care of water either as rains to store and use in necessity trying to bring it to Maracas  by  helping from state

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Publication Date
Wed Oct 04 2023
Journal Name
Arab Science Heritage Journal
المدراس الثانوية في الاعظمية ( ثانوية كلية بغداد- ثانوية الأعظمية للبنين – ثانوية الأعظمية للبنات - ثانوية الحريري للبنات) أنموذجاً
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Education received the attention of the monarchy in Iraq, especially after the developments that the country witnessed after Iraq gained independence and joined the League of Nations in 1932 AD in all political, economic and cultural aspects.  In this regard, due to its distinguished geographical location, where the atmosphere, the natural environment and the religious and political standing were available, which made it a center of attraction for most Iraqi families and political figures.  Learning and pioneering the path of knowledge, so it witnessed a great prosperity in secondary education, so several important schools appeared that contributed to advancing the wheel of learning forward, including Baghdad College High Schoo

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Publication Date
Tue Jan 01 2008
Journal Name
Journal Of Educational And Psychological Researches
أثر استخدام استراتيجيتي جانيه وميرل تينسون في اكتساب المفاهيم الجغرافية والاحتفاظ بها لدى طالبات الصف الرابع العام
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مشكلة البحث :-

     ظلت رغبة الانسان في المعرفة وفهم الكون الذي يعيش فيه ، ملازمة له منذ المراحل الاولى لتطور البشرية ، فالانسان بما يتمتع به من امكانات وقدرات وطاقات كامنة استطاع عن طريق تفاعله واحتكاكه الدائم والمستمر والخلاق مع البيئة المحيطة به ان يلاحظ ، ويتخيل ويتذكر ويفكر ويخطط ويبتكر ، مستفيداً من اخطائه في التعرف عليها ، وفي زيادة قدرته على التحكم فيها وتحسينها وتطويره

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Publication Date
Mon Jan 01 2007
Journal Name
Journal Of Educational And Psychological Researches
اتجاهات طالبات قسم رياض الاطفال نحو العمل في رياض الاطفال ( دراسة مقارنة كليتي التربية للبنات والتربية الاساسية )
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ان نجاح رياض الاطفال في تحقيق اهدافها يتوقف الى حد كبير على معلمة الروضة التي تزود الطفل بالخبرات ، فهي تمثل الام البديلة للطفل ، وتقع على عاتقها مسؤوليات نفسية واجتماعية واخلاقية نحو اطفال الروضة ، لدلك فان معلمة الروضة تقوم بعدة ادوار في رياض الاطفال ، فهي ممثلة لقيم المجتمع وتراثه التي تسعى الى غرسها في الطفل . 

 وعليه فان ليس كل من تتقدم للعمل في رياض الاطفال تصلح ان تكون معلمة ناجح

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Publication Date
Fri Feb 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
A Comparison of Parameters Estimation Methods for the Negative Binomial Regression Model under Multicollinearity Problem by Using Simulation
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This study discussed a biased estimator of the Negative Binomial Regression model known as (Liu Estimator), This estimate was used to reduce variance and overcome the problem Multicollinearity between explanatory variables, Some estimates were used such as Ridge Regression and Maximum Likelihood Estimators, This research aims at the theoretical comparisons between the new estimator (Liu Estimator) and the estimators

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Publication Date
Sun Mar 01 2009
Journal Name
Journal Of Economics And Administrative Sciences
Use the path analysis method to diagnoseFactors influencing the intentions of the employees of the University of Dhi Qar To introduce Internet behavior
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The purpose of this study is to diagnose factors that effect Thi-Qar behavioral intention to use internet. A sample of (127) internet users of university staff was taken in the study and were analyzed by using path analyze . The study concluded that there is a set of affecting correlation. It was founded that exogenous variables (gender, income, perceived fun, perceived usefulness, Image, and ease of use) has significant effect on endogenous (behavioral intention) . The result of analysis indicated that image hopeful gained users comes first, ease of use secondly, perceived fan and perceived usefulness on (dependent variables (daily internet usage and diversity of internet usage. Implication of these result are discussed . the st

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Publication Date
Sun Jun 18 2023
Journal Name
Arab Science Heritage Journal
أشهر العلماء العرب المسلمين وإسهاماتهم في علم الفلك من خلال كتاب سير أعلام النبلاء للذهبي (ت748هـ / 1348م)
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The Arabs muslim , throughout the historical ages, had many and varied contributions in various fields of science and knowledge, and in all scientific disciplines. They were preceded by scholars of other sects, so their books were translated into Arabic and they added to it many of their scientific research and writings that affected Arab and Islamic libraries, as these scientific research turned into basic references for the benefit of students of science in this field, and they did not stop at that, but built observatories, and invented They developed many astronomical devices in their time and observed the planets and stars, drew maps for them and determined their locations

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Publication Date
Mon Jan 20 2020
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Assessment of Long Distance Chasing Photometer (NAG-ADF-300-2) by Estimating the Drug Atenolol with Povidone Iodine Via CFIA
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     Atenolol was used with povidone iodine to prove the efficiency, reliability and repeatability of the long distance chasing photometer (NAG-ADF-300-2) using continuous flow injection analysis. The method is based on reaction between atenolol and povidone iodine in an aqueous medium. Optimum parameters was studied to increase the sensitivity development of method. Calibration graph was linear in the range of 2-19 mmol/L for cell A and 5-19 mmol/L for cell B. Limit of detection 146.4848 ng/55 µL and 2.6600 µg/200 µL respectively to cell A and cell  B. Correlation coefficient (r) 0.9957 for cell A and 0.9974 for cell. Relative standard deviation (RSD %) was lower than 1%, (n=8) for the determination of

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