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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
Sat Dec 02 2023
Journal Name
Journal Of Engineering
Discussion on the Structural Design Index and Design Method of Widening and Splicing Lane of Old Asphalt Pavement
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The splicing design of the existing road and the new road in the expansion project is an important part of the design work. Based on the analysis of the characteristics and the load effect of pavement structure on splicing, this paper points out that tensile crack or shear failure may occur at the splicing under the repeated action of the traffic load on the new/old pavement. According to the current structure design code of asphalt pavement in China, it is proposed that the horizontal tensile stress at the bottom of the splicing layer and the vertical shear stress at other layers of the splicing line should be controlled by adjusting the position and size of the excavated steps in addition to the conventional design ind

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Publication Date
Mon Jan 01 2024
Journal Name
Chemical Methodologies
Study of the biological activity and total antioxidant content of complexes derived from sulfonic acid and 4-hydroxybenzaldehyde
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The new liganed Schiff base named [(E)-3-hydroxy-4-((3,4,5- trimethoxybenzylidene)amino) naphthalene-1- sulfonic acid] was synthesized from 3,4,5-trimethoxybenzyldehyde and 1-amino-2-aphthol-4- sulfonic acid in equal molar ratio. A series of new metal complexes' of the common molecular formulation [M(L)2(H2O)2].H2O are synthesized and characterized by IR, UV–Vis spectra, mass spectra, atomic absorption, elemental analyses, chloride content, magnetic susceptibility and conductivity measurements as well as thermo gravimetric analysis (TGA, DSC). Consistent with results of the magnetic and spectral studies, the advised geometrical structures for all of the prepared complexes have been octahedral formula

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Publication Date
Mon Nov 16 2020
Journal Name
International Journal Of Psychosocial Rehabilitation
The effect of positive and negative flexibility exercises to develop special strength and effectiveness of 400m youth Hurdlers
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The research problem lies in: The use of positive and negative flexibility exercises to develop the special strength of the 400m hurdles player, that some young people face weakness and a problem in performance, which requires the need to prepare special exercises for physical and skill numbers using the types of exercises that have resilient strength, flexibility and have the effect on developing and determining the level of physical and skill performance. To develop 400m hurdles, special strength, explosive power and the characteristic velocity of arms and legs. Research aims: 1. Preparing positive and negative flexibility exercises to develop the special force and the effectiveness of 400m youth barriers. 2. Identify the effect of exerci

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Publication Date
Wed May 29 2019
Journal Name
Indian Journal Of Physics
Effect of lasing energy on the structure and optical and gas sensing properties of chromium oxide thin films
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Publication Date
Thu Jul 01 1999
Journal Name
Bulletin Of The Iraq Natural History Museum (p-issn: 1017-8678 , E-issn: 2311-9799)
Effect of juvenile hormone analogue and precoene II on the growth and metamorphosis of house fly Musca domwstica
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Larval instar duration of the house fly Musca domesticais influenced by the application of GHA and precocine. Topical use of ug / ul of JHA KID 183 prolonge Juvenile period compared to the control. On the contrary, application of ug / ul of precocine decreased it. Application of both substances has no effect. The emergence inhibitors were also influenced by such treatments. It reached 52.39% by the use of JHA, (-14.28%) by the use of precocine.

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Publication Date
Fri Feb 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
Work pressure of the administrative and academic members of Biskra University, its sources and its relation to some personal and functional variables
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  The study aimed to highlight the reality of the functional pressures with its dimensions (role ambiguity, role conflict, role burden, glass ceiling, and discrimination in composition). The researchers also relied on the questionnaire as a essential tool for data collection. The field study was conducted at the University of Mohammed Khiedr - Biskra -, the study was conducted on the basis of the total survey, which included all the workers of the 6 faculties of Biskra University (523 female employees).

     After the analyzing of the data using the version 21 of the statistical program Spss, The study reached a number of results, the most of them is the low level of the functiona

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Publication Date
Sat Jun 04 2022
Journal Name
Journal Of Inorganic And Organometallic Polymers And Materials
Improving the Mechanical Properties, Roughness, Thermal Stability, and Contact Angle of the Acrylic Polymer by Graphene and Carbon Fiber Doping for Waterproof Coatings
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Publication Date
Mon Oct 01 2018
Journal Name
Journal Of Educational And Psychological Researches
The instrumental support search strategies and avoid coping to psychological stressors and their relationship to the cognitive motivation of Al-Anbar University students.
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the Current research aims to identify the psychological stressors coping strategies and their relationship to the cognitive motivation among Al-Anbar University students through the following hypotheses: 1) no statistically significant differences at a level (0.05) among the sample according to the instrumental support strategy depending on the variable type and specialization, 2) No statistically significant differences at a level (0.05) among the sample in regard of coping avoiding strategy depending on the variable type and specialization, 3) There is no statistically significant difference at a level (0.05) in cognitive motivation level among Al-Anbar University students, 4) No statistically significant differences at a level (0.05)

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Publication Date
Wed Jun 03 2020
Journal Name
Political Sciences Journal
The Chinese-Russian role towards the Iranian nuclear program)An analytical study of formation and development according to international variables and future prospects(
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The Iranian nuclear program was one of the most prominent issues in the international arena, in light of Iran's insistence on using it in various ways, and according to international changes, it came under pressure from the American side to impose packages of sanctions, which continued to our time, as it went to Russia and China to gain support in developing its nuclear activities. And, by virtue of the common interests that are linked between them, Iran has received great support from the last two countries in all fields to reach the final agreement in 2015, regarding asserting the peace of these activities, in addition to lifting all restrictions represented in the previous sanctions according to the Security Council resolutions, Aldo

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Publication Date
Sat Feb 02 2019
Journal Name
Journal Of The College Of Education For Women
The Military Thinking and His Islamic balance in The Caliph Ali Bin Abi Talib ( peace is on him ) Compact to Malek Al Ashtar (God be pleased on him ): The Military Thinking and His Islamic balance in The Caliph Ali Bin Abi Talib ( peace is on him ) Compact to Malek Al Ashtar (God be pleased on him )
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Abstract
This study turns about The Military Thinking and His Islamic balance in
The Caliph Ali Bin Abi Talib ( peace is on him ) Compact to Malek Al Ashtar
(God be pleased on him )The military field is very wide in all intellectual and
practically effects at The Caliph Ali Bin Abi Taleb(peace is on him ). Its
considered the first seed for islam ,therefore,there are a lot from military
situtions which proved his practical experience in these affairs , and away
from the details of war and practical battles lets search the sample and the
academic study for fair military thinking (justice) in The Compact of Caliph Ali
to Malek Al Ashtar when he became the ruler of egypt.
The military fair thinking determines fr

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