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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 Nov 11 2011
Journal Name
Thesis
Performance Analysis of a New Compact Magneto-Rheological Proportional Control Valve for Hydraulic Actuation Using FEM and Experimental Approach
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One of the main parts in hydraulic system is directional control valve, which is needed in order to operate hydraulic actuator. Practically, a conventional directional control valve has complex construction and moving parts, such as spool. Alternatively, a proposed Magneto-rheological (MR) directional control valve can offer a better solution without any moving parts by means of MR fluid. MR fluid consists of stable suspension of micro-sized magnetic particles dispersed in carrier medium like hydrocarbon oil. The main objectives of this present research are to design a MR directional control valve using MR fluid, to analyse its magnetic circuit using FEMM software, and to study and simulate the performance of this valve. In this research, a

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Publication Date
Wed Jan 01 2025
Journal Name
Special Topics &amp; Reviews In Porous Media: An International Journal
EXPERIMENTAL AND NUMERICAL INVESTIGATION OF A DOUBLE PASS SOLAR AIR HEATER PROVIDED WITH POROUS ABSORBER PLATE FOR DRYING APPLICATIONS
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This investigation integrates experimental and numerical approaches to study a novel solar air heater aimed at achieving an efficient design for a solar collector suitable for drying applications under the meteorological conditions of Iraq. The importance of this investigation stems from the lack of optimal exploitation of solar energy reaching the solar collector, primarily attributable to elevated thermal losses despite numerous designs employed in such solar systems. Consequently, enhancing the thermal performance of solar collectors, particularly those employed in crop drying applications, stands as a crucial focal point for researchers within this domain. Two identical double-pass solar air heaters were designed and constructed for

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Publication Date
Wed Dec 15 2021
Journal Name
Al-academy
The aesthetic work of theatrical rehearsal and its directing applications "Taqasim on Al-Hayat Play as a model"
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This research reviews the aesthetic variables that were founded according to (theatrical rehearsal) as one of the most important pillars on which the theatrical process is based, because of its necessity in developing theatrical art on several levels that helped the theatrical director in organizing his work, and this became clear through the research chapters represented in the first chapter (methodological framework) and the second chapter, which consisted of the first topic (the duality of watching / rehearsal) and the second topic (the applications of theatrical rehearsal in theatrical experiences), all the way to the third chapter (research procedures), which included the analysis of theatrical rehearsals (sharing on life), and the

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Publication Date
Fri Jan 10 2025
Journal Name
Journal Of Ecological Engineering
Synthesis and characterization of magnetic nanoparticles coated with citric acid as a coagulant for the Tigris River treatment
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The coagulation and flocculation process using coated magnetic nanoparticles is considered one of the effective technologies for turbidity removal. This study investigates an application of magnetic nanoparticles coated with citric acid in the coagulation and flocculation process on Tigris River water in Baghdad, Iraq. Magnetic nanoparticles (MNP1) were synthesized by the co-precipitation method and coated with citric acid (MNP2). The prepared MNP1 and MNP2 were characterized by XRD, FTIR, AFM, FE-SEM, EDS, and zeta potential analysis. For coagulation process, the effect of different types of coagulants (alum, FeCl3, MNP1, MNP2), coagulant dosage (10–110 mg/l), and initial pH (3–9) were examined in this work. The best coagulant was MNP2

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Publication Date
Thu Nov 03 2022
Journal Name
Res Militaris
Prose of Sons of Imam Ali Al-Rida (Peace Be Upon Them): A Study Regarding the Structure of the Image and Its Implications - Simile as a Model
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Praise be to God, Lord of the Worlds, and prayers and peace be upon the most honorable of creation, Muhammad, whom God sent as a mercy to the worlds, and his pure God and his faithful companions. The Islamic heritage was replete with texts issued from among the pure infallibility, which constituted a prominent teacher that takes the student to stop there in search of its goals, purposes and beauty. The choice was made from those texts that were issued by the imams of Muslims in the Abbasid era, namely Imam Muhammad al-Jawad, his son Imam Ali al-Hadi and his grandson Imam Hassan Zaki al-Askari. (Peace be upon them), and scholars have called them (sons of satisfaction), and researchers have shed light on these texts from rhetorical, artistic

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Publication Date
Sat Aug 01 2026
Journal Name
Journal Of Taibah University Medical Sciences
The key role of RANKL and OPG as molecular biomarkers in bone remodeling associated with different grafts regarding socket preservation: A systematic review
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Objectives: Bone remodeling usually depends on complex molecular signaling, where receptor activator of NF-B ligand (RANKL) and osteoprotegerin (OPG) serve as key modulators that regulate osteoclastogenesis and overall bone metabolism process. This systematic review aimed to evaluate the influence of different graft materials on RANKL and OPG expression following alveolar ridge preservation. Methods: An electronic search of the literature was performed in Embase via Ovid, Medline via Ovid, CINAHL, Scopus and Web of Science databases, in addition to a manual search regarding all related articles. PRISMA guidelines and PICO framework were followed in this systematic review. The inclusion criteria were limited to English-published studies

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Publication Date
Sat Mar 31 2018
Journal Name
Journal Of Engineering
Potential of Microalgae Cultivation in Dairy Wastewater as a Step in Low-Cost Biofuel Production
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The present study addresses adopting the organic and nutritious materials in dairy wastewater as media for cultivation of microalgae, which represent an important source of renewable energy. This study was carried out through cultivation of three types of microalgae; Chlorella sp., Synechococcus, and Anabaena. The results shows the success the cultivation of the Synechococcus and  Chlorella Sp, while the Anabaena microalgae were in low-growth level. The highest growth was in the Synechococcus farm, followed by Chlorella and Anabaena. However, the growth of Synechococcus required 10 days to achieve this increase that re

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Publication Date
Fri Dec 01 2023
Journal Name
Case Studies In Construction Materials
Experimental and environmental investigations of the impacts of wood sawdust on the performance of reinforced concrete composite beams
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Publication Date
Wed Jan 01 2020
Journal Name
2nd International Conference On Materials Engineering &amp; Science (iconmeas 2019)
A kinetic model for prodigiosin production by Serratia marcescens as a bio-colorant in bioreactor
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Publication Date
Mon Dec 18 2017
Journal Name
Al-khwarizmi Engineering Journal
Experimental Investigation on the Emission Characteristics of a Dual – Fuel Micro Gas Turbine by Injecting Ethanol into Compressor Inlet Air
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Pollutants generation is strongly dependant on the firing temperature and reaction rates of the gaseous reactants in the gas turbine combustion chamber. An experimental study is conducted on a two-shaft T200D micro-gas turbine engine in order to evaluate the impact of injecting ethanol directly into the compressor inlet air on the exhaust emissions. The study is carried out in constant speed and constant load engine tests. Generally, the results showed that when ethanol was added in a concentration of 20% by volume of fuel flow; NOx emission was reduced by the half, while CO and UHC emissions were almost doubled with respect to their levels when burning conventional LPG fuel alone.

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