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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
Wed Aug 31 2022
Journal Name
Al-kindy College Medical Journal
A Population based Study on Self Medication Practice in Pakistan
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Background: The risk of antibiotics resistance (AR) increases due to excessive of antibiotics either by health care provider or by the patients.

Objective: The assessment of the self-medication Practice of over the counter drugs and other prescription drugs and its associated risk factor.

Subjects and Methods: Study design: A descriptive study was conducted from “20th December 2019 to 08th January 2021”. A pre validated and structured questionnaire in English and Urdu language was created to avoid language barrier including personal detail, reasons and source and knowledge about over the counter drugs and Antibiotics. Sample of the study was randomly selected.

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Publication Date
Fri May 01 2015
Journal Name
Journal Of Engineering
On Gradient Descent Localization in 3-D Wireless Sensor Networks
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Localization is an essential demand in wireless sensor networks (WSNs). It relies on several types of measurements. This paper focuses on positioning in 3-D space using time-of-arrival- (TOA-) based distance measurements between the target node and a number of anchor nodes. Central localization is assumed and either RF, acoustic or UWB signals are used for distance measurements. This problem is treated by using iterative gradient descent (GD), and an iterative GD-based algorithm for localization of moving sensors in a WSN has been proposed. To localize a node in 3-D space, at least four anchors are needed. In this work, however, five anchors are used to get better accuracy. In GD localization of a moving sensor, the algo

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Publication Date
Wed Dec 01 2021
Journal Name
Journal Of Economics And Administrative Sciences
THE MEDIATING ROLE OF PRODUCT INNOVATION ON THE RELATIONSHIP BETWEEN MARKETING INFORMATION SYSTEM AND CUSTOMER ORIENTATION
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 Marketing information system (KMIS) is an essential factor of developing business’ performance and getting sustainable success. The main goal of the research is to measure effect of MIS on customer orientation and product innovation. Also, another goal is to analyze the mediation role of product innovation in relationship MIS and customer orientation. This study sought to analyze the marketing information system and measure its effect on the customer orientation and product innovation. The data of the study were collected using questionnaire. The data were analyzed using statistical tools and SPSS programming. The results of the study showed that the KMIS can positively and significantly effect product innovation. Also, t

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Publication Date
Wed Aug 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
Integration of e-commerce, information technology and its impact on reducing costs to make pricing decisions
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   E-commerce is the most important result of information technology in this day and age, has resulted in the use of commercial transactions to changes in economic, social, and psychological, and produced a new type of shopping, jobs, and create new job opportunities, and changed the traditional work environment. The challenge currently facing economic units is how to transfer this technology and its integration within the community, especially after the massive developments that have occurred in the areas of commercial and congested markets units, the economic and the products and services the many and varied and intensified competition among these units to achieve a profit, leading to the emergence of e-commerce as on

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Publication Date
Sun Apr 10 2022
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
أثر خصائص لجنة التدقيق في الإفصاح عن رأس المال الفكري: أدلة من فسطين: The Impact of Audit committee characteristics on Intellectual capital disclosure : Empirical evidence from Palestine
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The study aimed to examine the impact of audit committee characteristics on the practices of intellectual capital disclosure in the annual reports of Bank and Insurance companies listed on Palestine Exchange, through performing content analysis of the annual reports for the study sample which totaled thirteen companies, including six banks and seven insurance companies. To achieve the study objectives, the study employed a content analysis approach in order to analyze the content of the intellectual capital disclosure practice, in addition, the study used cross-sectional with longitudinal data for time series for a period of time between 2014-2019. The empirical results indicated that financial expertise and the number of meeting

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Publication Date
Mon Apr 04 2022
Journal Name
Journal Of Educational And Psychological Researches
The Effect of Sample Size on the Item Differential Functioning in the Context of Item Response Theory
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The current study examined the effect of different sample sizes to detect the Item differential functioning (DIF). The study has used three different sizes of the samples (300, 500, 1000), as well as to test a component of twenty polytomous items, where each item has five categories. They were used Graded Response Model as a single polytomous item response theory model to estimate items and individuals’ parameters. The study has used the Mantel-Haenszel (MH) way to detect (DIF) through each case for the different samples. The results of the study showed the inverse relationship between the sample size and the number of items, which showed a differential performer.

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Publication Date
Wed Sep 30 2020
Journal Name
مجلة كلية الادارة والاقتصاد للدراسات الاقتصادية والادارية والمالية - بابل
أثر المقدرة الجوهرية في تعزيز الأداء الاستراتيجي و تحقيق الميزة التنافسية في القطاع الصناعي : بحث تطبيقي في عينة من شركات القطاع الصناعي
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Publication Date
Wed Mar 04 2026
Journal Name
Sport Culture
Some bio-motor abilities and their relationship to the skill of standing on the hands followed by the forward roll on the mat of floor movements in artistic gymnastics for women
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The research consists of five chapters, and in the first chapter, it addresses the introduction and importance of the research, where the researcher explained the importance of bio-motor abilities and their role in achieving a high level through their connection to the skill performance of standing on the hands followed by the forward roll, and the research problem: Do these bio-motor abilities have an impact on the level of skill performance? Handstand followed by forward roll.

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Publication Date
Sat Sep 30 2017
Journal Name
College Of Islamic Sciences
Internal music in the poetry of guidance In the era of Islam and its effects Artistic and semantic
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In this research entitled "Internal music in the poetry of guidance in the era of Islam and its artistic and semantic implications" dealt with the following:
 Preface, which addressed the importance of internal music in poetry, and its close association with poetry, and the poet himself, to reveal what is touring himself and revolves in his imagination.
 Repetition of all kinds: repetition of letters, repetition of words, and repetition of phrases: It showed what this repetition of strengthening the melody, and linking parts of words within the same house, or the poem, and create a special musical atmosphere to spread a certain significance and to confirm the meanings and accompanied by musical accommodation.
 Anaphysic

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Publication Date
Fri Sep 30 2022
Journal Name
College Of Islamic Sciences
Principles of war and jihad to protect the environment and civilians in times of war in Islamic Sharia
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Research summary

Islam protects the environment and civilians in peace and war, and in international humanitarian law protection of the environment and civilians in international conflicts only. As for wars and internal conflicts, it is not within the jurisdiction of international humanitarian law. In Islamic law, the principles of protecting the environment and civilians are fixed in all wars and conflicts, whether internal or external, local. or international.

Islam laid down moral principles in war, including:

- Preserving the environment and avoiding corruption in the land by burning trees and killing animals unnecessarily.

- Not to be exposed to non-combatants, including women, boys, the elderly, the disa

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