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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
Thu Dec 26 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
تقويم تحقق العدالة الضريبية في ظل طرق واساليب تقدير ضريبة الدخل: دراسة تطبيقية في الهيئة العامة للضرائب
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Tax justice is one of the important principles that any tax system seeks to achieve because it is an important and important pillar of the tax because it has negative repercussions on the tax accounting process on the one hand and the low tax revenues on the other hand. Therefore, countries have sought through their tax systems to use methods and methods In the process of estimating taxable incomes to achieve that justice depending on the awareness of their communities. The method adopted differs from one country to another according to the knowledge and understanding of the society of that state for taxation and its role in economic, social and political life. In Iraq, the General Authority for Taxation Methods of estimating taxable inc

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Publication Date
Tue Jun 01 2021
Journal Name
Journal Of The College Of Languages (jcl)
The passive of verbs constructed with prepositions: Das Passiv der mit Präpositionen konstruierten Verben
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 Verbs in German and Arabic are of two types: active and passive. Passive voice  is a grammatical voice construction that is found in many languages.  Out of grammatical perspective, each main verb has a form in the active and one in the passive known as a "genus verbi" (type of verb). In passive voice, both in German and in Arabic, the focus is on the action itself or on the result of the action; often the perpetrator is not mentioned. In German, to conjugate verbs in the passive voice, you must know the forms of werden (to become). German uses werden  + the past participle and states it at the end of a sentence. In Arabic,

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Publication Date
Sun Jul 02 2006
Journal Name
Journal Of Educational And Psychological Researches
اثر المعرفة المسبقة بالأهداف السلوكية في تحصيل طالبات قسم القران الكريم والتربية الإسلامية في مادة احكام التلاوة
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مشكلة البحث

إن طرائق تدريس المواد الشرعية ما تزال تُدّرس بطرائق لا تتناسب مع ما توصل إليه البحث العلمي في الميدان التربوي في الوقت الحاضر ، وهذا مما سبب في وجود أزمة فكرية وعلمية في الأقسام التي تدرس المناهج الدينية .

على الرغم من الأهمية الكبيرة لمادة التلاوة ، إلا أن هناك مشكلة كثيرا ما يعاني منها مدرسو هذه المادة، وهي انصراف الطلبة عن حفظ النصوص القرآن

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Publication Date
Thu Jan 23 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
استخدام بطاقة الأداء المتوازن في تقويم الأداء: دراسة محاسبية في شركة بغداد للمشروبات الغازية من المنشآت الصناعية
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The performance evaluation had Focused for many years ago on The financial factors which are Not enough for the contemporary business organizations. So in order to get useful information it con used The balanced score card which can used to offer information about some measurement on which the level of the act actual performance is determined.

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Publication Date
Wed Oct 04 2023
Journal Name
Exergy - New Technologies And Applications
High Synthetic Image Coding System
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Compressing an image and reconstructing it without degrading its original quality is one of the challenges that still exist now a day. A coding system that considers both quality and compression rate is implemented in this work. The implemented system applies a high synthetic entropy coding schema to store the compressed image at the smallest size as possible without affecting its original quality. This coding schema is applied with two transform-based techniques, one with Discrete Cosine Transform and the other with Discrete Wavelet Transform. The implemented system was tested with different standard color images and the obtained results with different evaluation metrics have been shown. A comparison was made with some previous rel

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Publication Date
Sun Jun 12 2011
Journal Name
Baghdad Science Journal
SlantletTransformbased VideoDenoising
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A technique for noise removal is proposed based on slantlet transform. The proposed algorithm tends to reduce the computational time by reducing the total number of frames through dividing the video film into sub films, finding master frames, applying the slantlet transform which is orthogonal discrete wavelet transform with two zero moments and with improved time localization. Thresholding technique is applied to the details coefficients of the slantlet transform .The denoised frame is repeated to retain the original frame sequence. The proposed method was applied by using MATLAB R2010a with video contaminated by white Gaussian noise .The experimental results show that the proposed method provides better subjective and object

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Publication Date
Sat Jun 01 2013
Journal Name
Engineering And Technology Journal
Performance Improvement of Multi-UserMC-CDMA system Using Discrete Hartly Transform Mapper
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Future wireless communication systems must be able to accommodate a large number of users and simultaneously to provide the high data rates at the required quality of service. In this paper a method is proposed to perform the N-Discrete Hartley Transform (N-DHT) mapper, which are equivalent to 4-Quadrature Amplitude Modulation (QAM), 16-QAM, 64-QAM, 256-QAM, … etc. in spectral efficiency. The N-DHT mapper is chosen in the Multi Carrier Code Division Multiple Access (MC-CDMA) structure to serve as a data mapper instead of the conventional data mapping techniques like QPSK and QAM schemes. The proposed system is simulated using MATLAB and compared with conventional MC-CDMA for Additive White Gaussian Noise, flat, and multi-path selective fa

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Publication Date
Sat Dec 01 2012
Journal Name
Iraqi Journal Of Physics
Wavelet compression for remotely sensed images
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Image compression is very important in reducing the costs of data storage transmission in relatively slow channels. Wavelet transform has received significant attention because their multiresolution decomposition that allows efficient image analysis. This paper attempts to give an understanding of the wavelet transform using two more popular examples for wavelet transform, Haar and Daubechies techniques, and make compression between their effects on the image compression.

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Publication Date
Mon Jan 01 2018
Journal Name
Research Journal Of Pharmacy And Technology
Impact of Human Cytomegalovirus Infection associated with the expressed protein of mutated <i>BRCA1</i> gene in breast tissues from a group of Iraqi Female Patients with Breast Carcinoma
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Publication Date
Wed Sep 20 2006
Journal Name
00
INVESTIGATING SOME OF THE SYNTACTIC ERRORS MADE BY EFL COLLEGE STUDENTS IN WRITTEN ENGLISH EXPRESSIONS استقصاء بعض الاخطاء النحوية لطلبة الكلية دارسي اللغة الانكليزية لغة اجنبية في التعابير الانشائية
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