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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
Sat Dec 28 2024
Journal Name
Dental Hypotheses
Assessment of Color Change of Artificial White Spot Lesions after Sandblasting with Bioactive Glass, Resin Infiltration, or Microabrasion Followed by Color Stability Test by pH Cycling: An in Vitro Study
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Introduction: This study aimed to assess the color change of human teeth with artificial enamel white spot lesions (WSLs) after sandblasting with bioactive glass, resin infiltration, and microabrasion and to test color stability after pH cycling. Methods: Fifty extracted human mandibular first molars were randomly assigned into five groups: Sound, WSLs (untreated), and WSLs sandblasted with bioactive glass (Sylc), WSLs treated by resin infiltration (ICON), and WSLs treated by microabrasion (Opalustre), respectively. All specimens underwent a pH cycling procedure. The color parameters for each specimen were assessed using an Easyshade dental spectrophotometer at different time stages then the color changes (ΔE) were calculated. Results: The

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Publication Date
Sat Feb 27 2021
Journal Name
Journal Of Engineering
Improvement of Unconfined Compressive Strength of Soft Clay using Microbial Calcite Precipitates
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The precipitation of calcite induced via microorganisms (MICP) is a technique that has been developed as an innovative sustainable ground improvement method utilizing ureolytic bacteria to soil strengthening and stabilization. Locally isolated Bacillus Sonorensis from Iraqi soil samples were found to have high abilities in producing urease. This study aims to use the MICP technique in improving the undrained shear strength of soft clay soil using two native urease producing bacteria that help in the precipitation of calcite to increase the cementation between soil particles. Three concentrations of each of the locally prepared Bacillus sonorensis are used in this study for cementation reagent (0.25M, 0.5M, and 1M) during

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Publication Date
Mon Jan 27 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
استعمال أنموذج عائد رأس المال المعدل بالمخاطر (RAROC) في إدارة المخاطر المصرفية: دراسة في عينة من المصارف العراقية الخاصة
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The bank risks has greaten and changed in its nature under the developments of financial liberalization, banking innovation and increasing use for new financial instruments which created by the huge technological advancement happened in the banking  industry. So that, banks in large choose to base the profitability measures adjusted for risks; that is we introduced this research. The most important reason led us to do this is the restriction to use the modern statistical methods by trade bank in Arab countries equally with world banks which were the antecedent to base those models. Therefore, the research problem is embedded in the banks need to use measures that link between profitability and risks and this is what achieved by RARC

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Publication Date
Tue Dec 01 2009
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
دور مراقب الحسابات في تعزيزالإفصاح بالتقارير المالية في ظل حوكمة الشركات: دراسة تحليلية للقوائم المالية للشركة العامه للصناعات المطاطية
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The subject of disclosure, transparency and corporate governance taking globally significant attention recently, especially after the collapse of many large companies because the level of disclosure and transparency is an important measure of the effectiveness and reliability of the system of governance in the companies, the equity in the provision of correct information and clear and complete in a timely manner to all stakeholders in the life of the company with whom in relation  strengthen the confidence the company's management systems and automatic guide the staff and the decision-making.
    The research aims to shed light on the concept of corporate governance, and the reasons and motives of the spread

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Publication Date
Wed Feb 18 2026
Journal Name
Sciences Journal Of Physical Education
تاثير تمرينات اللعب بمساحات مختلفة في تطوير التحمل الخاص في دقة اداء بعض المهارات الاساسية للاعبي كرة القدم الشباب
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مستخلص البحث أهمية البحث عن طريق إعداد برنامج تدريبي يعتمد هذه الطريقة التدريبية في تطوير التحمل الخاص عن طريق العمل على بناء مستوى جيد من التحمل الخاص لدى اللاعبين الشباب في مرحلة الإعداد الخاص, تحقيق نتائج جيدة على مستوى أداء الواجبات المهارية والخططية المطلوبة منه في أثناء زمن المباراة, حيث ارتأت الباحثة من خلال إعداد برنامج تدريبي إلى رفع مستوى (التحمل الخاص) لدى لاعبي كرة القدم وبالتالي يمكنها أن تساع

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Publication Date
Fri Jun 01 2012
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
الممارسات القيادية لرؤساء أقسام الهيئة العامة للضرائب في ظل نظرية شبكة القيادة الإدارية: دراسة تطبيقية في الهيئة العامة للضرائب
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The aim of this study is know the five leadership practices according to the theory of network of leadership by Black and Mouton for the presidents of the Taxation General Board from their prospective, that is through answering the questionnaire questions. To achieving the objectives of this study, the researcher organized a questionnaire form as a main instrument for data collection. It includes (30) items distributed into five leadership practices according to the theory of network of leadership. Each one is subdivided into (6) questions.

The questionnaire was distributed to the presidents of the Taxation General Board of (14). The researcher used the SPSS program to analyses the answers. Through the answers, h

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Publication Date
Mon Oct 01 2007
Journal Name
Journal Of Educational And Psychological Researches
اسباب السرقة لدى تلاميذ المرحلة الابتدائية من وجهة نظر المعلمين والمعلمات في المدارس الابتدائية في مدينة المكلا بمحافظة حضرموت
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يهدف البحث الحالي التعرف على اسباب السرقة لدى تلاميذ المرحلة الابتدائية كما يراها معلموهم ومعلماتهم ، وعن الاساليب المتبعة في معالجة ظاهرة السرقة من قبلهم ، ولقد شملت عينة البحث على ( 200 ) فرداً من معلمي ومعلمات تلاميذ المرحلة الابتدائية في مدينة المكلا للعام الدراسي ( 2004 ـ 2005 ) ، وقد استخدمت الباحثة استبياناً أعدته كأداة للوصول الى اهداف البحث بعد ان تم التأكد من صدقه وثباته ، استخدمت الباحثة معادلة ارتب

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Publication Date
Thu Dec 26 2019
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
امكانية استخدام محاسبة التكاليف في تحديد تكلفة الانتاج لاغراض ضريبة القيمة المضافة: دراسة أستطلاعية تحليلية في الهيئة العامة للضرائب
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         This research is important because of the importance of the subject matter and the implications for the future of development in Iraq. This requires linking the accounting systems with the economic developments. The accounting system we will address in this research is the cost accounting system and its role in determining value added tax. The value added tax and the extent of the relationship with the general accounting principles of cost accounting through which the value added is determined provided the use of a sound and effective cost system.

      The problem of research was about knowing the role of cost accounting in determining the value added

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Publication Date
Wed Aug 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
The Impact of Using the international standard for Training (ISO-10015) to Improve the Quality of the Control Activity – A Survey Study at the Federal Board of Supreme Audit.
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The great  importance of training made it as an investment for the organization, and assert the Quality of performance which support it by prepare the employee to the Current and future Jobs . The Research problem a rounded about How to measure the impact of training based on (ISO 10015) and its effect on the Quality of performance , How to evaluation the results of training to attained the training goals . The Research aims to find out the effects of application of international standard guidelines (ISO 10015) to attained the quality of audit work achieved in the Federal Board of Supreme Audit. The Research sought to achieve a number of objectives cognitive and applied on the basis of four key assumptions, and other su

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Publication Date
Tue Jun 01 2010
Journal Name
Journal Of Economics And Administrative Sciences
دور التمويل الذاتي في إعادة اعمار الوحدات الحكومية غير الهادفة للربح "دراسة تطبيقية في كلية الإدارة والاقتصاد/ جامعة بغداد"
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The Iraqi non profit governmental units are facing great financing challenges in providing the money required for reconstructing the damages occurred after 9th of April 2003.

Related to that, This research, which is contained of studying the self – financing experiment in non profit governmental units which is considered one of the financing alternatives that contribute in providing the required money to meet the shortage of central finance; and creating the economic exploitation for the resources and possibilities achieved by the non profit governmental units themselves for the purpose of employ them in reconstruction and to reduce the burden on the public budget which is responsible of fin

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