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Theoretical and Experimental Reflection Coefficients in Flexible Tubes as a Function of the Mach Number
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The standard formulation of Wave Intensity Analysis (WIA) assumes that the flow velocity (U) in the conduit is <;<; the velocity of propagation of waves (c) in the system, and Mach number, M=U/c, is negligible. However, in the large conduit arteries, U is relatively high due to ventricular contraction and c is relatively low due to the large compliance; thus M is > 0, and may not be ignored. Therefore, the aim of this study is to identify experimentally the relationship between M and the reflection coefficient in vitro. Combinations of flexible tubes, of 2 m in length with isotropic and uniform circular cross sectional area along their longitudinal axes, were used to present mother and daughter tubes to produce a range of reflection coefficients. An approximately semi-sinusoidal pulse was generated at the inlet of the mother tube using a syringe pump, first in the condition of initial velocity, U 0 =0, and when U 0 >0 with steady flow to superimpose the pulse. Pressure (P) and Velocity (U) were measured in the mother tube, wave speed was determined using the foot to foot and PU-loops methods. The theoretical reflection coefficient, R t at M=0, has been compared to the experimental reflection coefficient, R at M>0, which was determined as dP-/dP+ as calculated using WIA. The function R(M) changes significantly with the geometrical and mechanical features of the connected tubes. In our experiments, R increased significantly with small values of M. In the range of M=0-0.02, R increased by 4-36%. Therefore, we conclude that M significantly affects the magnitude of reflections.

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Publication Date
Fri Jan 05 2018
Journal Name
Asian Quarterly: An International Journal Of Contemporary Issue
Refugees and the Challenges for Language Education (LE): A Theoretical Study
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DBN Rashid, Asian Quarterly: An International Journal of Contemporary Issue, 2018

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Publication Date
Tue Jul 20 2021
Journal Name
Materials Science Forum
Investigation into the Distribution of Erosion-Corrosion in the Furnace Tubes of Oil Refineries
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Crude oil is one of the most important sources of energy in the world. To extract its multiple components, we need oil refineries. Refineries consist of multiple parts, including heat exchangers, furnaces, and others. It is known that one of the initial operations in the refineries is the process of gradually raising the temperature of crude oil to 370 degrees centigrade or higher. Hence, in this investigation the focus is on the furnaces and the corrosion in their tubes. The investigation was accomplished by reading the thickness of the tubes for the period from 2008 to 2020 with a test in every two year, had passed from their introduction into the work. Where the thickness of more than one point was measured on each tube in the sa

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Publication Date
Mon Aug 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
The effects of human error in the banking risks - Empirical study in a number of Iraqi private banks
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Abstract

This research aims to study human error effects in the banking risks in the private banks  through the measurement and testing of human error effect in every kind of banking risks types and stand on the most closely associated with the risks in order to focus on them and make appropriate processors have with respect to and increase the availability of skills and expertise required to carry out banking operations of error-free manner.

Find dealt with human error in terms of meaning and understandable, classifications and types, causes and consequences and its approaches and theories. Also addressed placed banking risks in terms of meaning and concept, species and entr

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Publication Date
Wed Aug 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
The Impact of knowledge Workers in Organizational Excellence Field research in a number of the Iraqi industrial companies
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The Knowledge Workers is The Largest And Most Powerful Resource Of The Organizational Excellence it is A Precious  Treasure, Therefore Find Organizations at present is looking for them and seek to invest their ideas For achieving excellence, creativity and access to the excellence Organizational , As a result of their importance in terms of engagement and influence in the success or failure of the as an organizational Of The Research is Measuring The Correlation And  Impact Between Knowledge Workers And Organizational Excellence in Sample Of Companies Iraqi Industrial By Standing The Dimensions Of Knowledge Workers ( Characteristics , Skills , Roles , Competencies ) And

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Publication Date
Thu Sep 30 2010
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
CORROSION of BOILER TUBES in SOUTH BAGHDAD ELECTRIC STATION
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The corrosion of low carbon steel boiler tubes in demi water had been investigated. The purpose of this investigation was to determine the change produced in corrosion behavior of the carbon steel as a result of the specific presence of chloride and copper ions in the water under different temperatures. For low carbon steel experiments, the temperature was taken in three levels (125, 175, and 215°C) under about 27 bar pressure and 1500 rpm in autoclave. Using weight loss technique, the corrosion rate ranges from (85 to 789 gmd) for low carbon steel boiler tubes.

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Publication Date
Fri Aug 20 2021
Journal Name
Iraqi Journal Of Laser
Design of Tunable Optical Band Pass Filter based on in-Line PM-Mach Zehnder Interferometer
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In this paper, tunable optical band-pass filters based on Polarization Maintaining Fiber –Mach Zehnder Interferometer presented. Tunability of the band-pass filter implemented by applying different mechanical forces N on the micro-cavities splicing regions (MCSRs). The micro-cavity formed by using three variable-lengths of single-mode polarization-maintaining fiber with (8, 16, 24) cm lengths, splice between two segments of (SMF-28) with (26, 13) cm lengths, using the fusion splicing technique.  Ellipsoidal shape micro-cavities experimentally achieved parallel to the propagation axis having dimensions between (12-24) μm of width and   (4-12) μm of length. A micro-cavity with width and length as high as 24 μm and 12 μ

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Publication Date
Tue Dec 01 2020
Journal Name
Journal Of Economics And Administrative Sciences
The economic implications of the housing problem In Iraq and ways to address it - a theoretical research
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The problem of housing in Iraq is a long-rooted and rooted problem, and it needs a great effort to find out its causes and thus give essential points that contribute to alleviating and addressing it, and it is worth noting that research into the housing problem and the housing sector in Iraq is not done in isolation from other sectors and studies. As well as the economic policies pursued and the social and political conditions. It is known that the Iraqi economy is a unilateral (rentier) economy, that is, it depends almost entirely on exporting oil and obtaining revenues, and that the economic decision and economic policies followed in Iraq are greatly affected by several factors, including the economic, social and political fact

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Publication Date
Sat Jan 01 2022
Journal Name
Materials Research Express
Thermochromic and opacity behaviors in vanadium dioxide nanofilms: a theoretical study
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Abstract<p>Vanadium dioxide nanofilms are one of the most essential materials in electronic applications like smart windows. Therefore, studying and understanding the optical properties of such films is crucial to modify the parameters that control these properties. To this end, this work focuses on investigating the opacity as a function of the energy directed at the nanofilms with different thicknesses (1–100) nm. Effective mediator theories (EMTs), which are considered as the application of Bruggeman’s formalism and the Looyenga mixing rule, have been used to estimate the dielectric constant of VO<sub>2</sub> nanofilms. The results show different opacity behaviors at different w</p> ... Show More
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Publication Date
Sat Jan 01 2022
Journal Name
Materials Research Express
Thermochromic and opacity behaviors in vanadium dioxide nanofilms: a theoretical study
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Abstract<p>Vanadium dioxide nanofilms are one of the most essential materials in electronic applications like smart windows. Therefore, studying and understanding the optical properties of such films is crucial to modify the parameters that control these properties. To this end, this work focuses on investigating the opacity as a function of the energy directed at the nanofilms with different thicknesses (1–100) nm. Effective mediator theories (EMTs), which are considered as the application of Bruggeman’s formalism and the Looyenga mixing rule, have been used to estimate the dielectric constant of VO<sub>2</sub> nanofilms. The results show different opacity behaviors at different w</p> ... Show More
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Publication Date
Tue Aug 15 2023
Journal Name
Al-academy
Government slogans and the reflection of visual identity in their designs
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There is no doubt that development is a human necessity and an urgent technical imperative that science imposes on all aspects of societal life. Especially in the field of graphic design, as logos are among the most prominent graphic achievements of an interactive nature with the requirements of the technical and functional era to serve the recipient and the continuity of interaction with him through a visual message sent to him constantly to remind him of what he interacted with in advance, which is known as visual identity, and during the process of developing logos especially And by providing designs that suit the contemporary technical and functional development, we often see the logo lose its visual identity. Therefore, the research

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