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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
Tue Feb 01 2022
Journal Name
Baghdad Science Journal
Theoretical and Experimental Study of Corrosion Behavior of Carbon Steel Surface in 3.5% NaCl and 0.5 M HCl with Different Concentrations of Quinolin-2-One Derivative
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A theoretical and protection study was conducted of the corrosion behavior of carbon steel surface with different concentrations of the derivative (Quinolin-2-one), namely 7-Ethyl-4-methyl-1-[(4-nitro-benzylidene)-amino]-1H-quinolin-2-one (EMNQ2O). Theoretically, Density Functional Theory (DFT) of B3LYP/ 6-311++G/ 2d, 2p level was carried out to calculate the geometrical structure, physical properties and chemical inhibition chemical parameters, with the local reactivity in order to predict both the reactive centers and to know the possible sites of nucleophilic and electrophilic attacks, in vacuum and two solvents (DMSO and H2O), all at the equilibrium geometry. Experimentally, the inhibition efficiencies (%IE) in (3.5% NaCl)

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Publication Date
Wed Jun 01 2011
Journal Name
Journal Of Economics And Administrative Sciences
Competitiveness of an enterprise under a flexible manufacturing system. Manufacturing strategy and flexibility - Case study
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The research has designed for studying the relationship between manufacturing strategy and its flexibility under the flexible manufacturing system with their reflection on the competitive environmental performance of the firm. To interpret and tackle the problem, a hypothesis has formulated stating that “ the competitive performance of a firm is interpreted by the manufacturing strategy and flexibility which are derived from the firm and its business  strategies under the flexible manufacturing system”. Related literatures with their theoretical dissertations, which enhanced the thoughtful content, have analyzed. An illustrative case study on the flexible manufacturing system at Toyota Motors Corporation working at the g

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Publication Date
Mon Dec 25 2023
Journal Name
Optical Materials
Impact of a precise pH value change on the characteristics of deposited tin monosulphide films onto a flexible substrate
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The chemical bath deposition technique (CBD) is considered the cheapest and easiest compared with other deposition techniques. However, it is highly sensitive to effective parameter deposition values such as pH, temperature, and so on. The pH value of the reaction solution has a direct impact on both the nucleation and growth rate of the film. Consequently, this study presents a novel investigation into the effect of a precise change. in the pH reaction solution value on the structural, morphological, and photoresponse characteristics of tin monosulphide (SnS) films. The films were grown on a flexible polyester substrate with pH values of 7.1, 7.4, and 7.7. The X-ray diffraction patterns of the grown films at pH 7.1 and 7.4 confirmed

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Publication Date
Sat Apr 01 2023
Journal Name
Baghdad Science Journal
A Theoretical Study of the Docking of Medicines with some Proteins
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A set of ten drug compounds containing an amino group in the structure were determined theoretically. The parameters were entered into a model to forecast the optimal values of practical (log P) medicinal molecules. The drugs were evaluated theoretically using different types of calculations which are AM1, PM3, and Hartree Fock at the basis set (HF/STO-3G). The Physico-chemical data like (entropy, total energy, Gibbs Free Energy,…etc were computed and played an important role in the predictions of the practical lipophilicity values. Besides, Eigenvalues named HOMO and LUMO were determined. Linearity was shown when correlated between the experimental data with the evaluated physical properties. The statistical analysis was used to analy

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Publication Date
Thu May 14 2020
Journal Name
Journal Of Planner And Development
Cities of Lebanon from "Planning to Congestion Towards a "flexible mobility culture
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This paper examines the change in planning pattern In Lebanon, which relies on vehicles as a semi-single mode of transport, and directing it towards re-shaping the city and introducing concepts of "smooth or flexible" mobility in its schemes; the concept of a "compact city" with an infrastructure based on a flexible mobility culture. Taking into consideration environmental, economical and health risks of the existing model, the paper focuses on the four foundations of the concepts of "city based on culture flexible mobility, "and provides a SWOT analysis to encourage for a shift in the planning methodology.

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Publication Date
Wed May 10 2023
Journal Name
Journal Of Engineering
Vibration Control Analysis of a Smart Flexible Cantilever Beam Using Smart Material
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This paper features the modeling and design of a pole placement and output Feedback control technique for the Active Vibration Control (AVC) of a smart flexible cantilever beam for a Single Input Single Output (SISO) case. Measurements and actuation actions done by using patches of piezoelectric layer, it is bonded to the master structure as sensor/actuator at a certain position of the cantilever beam.
The smart structure is modeled based on the concept of piezoelectric theory, Bernoulli -Euler beam theory, using Finite Element Method (FEM) and the state space techniques. The number of modes is reduced using the controllability and observability grammians retaining the first three
dominant vibratory modes, and for the reduced syste

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Publication Date
Fri Nov 13 2020
Journal Name
Mechanics Of Advanced Materials And Structures
Enhancing the strength of reinforced concrete columns using steel embedded tubes
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This paper demonstrates an experimental and numerical study on the behavior of reinforced concrete (RC) columns with longitudinal steel embedded tubes positioned at the center of the column cross-section. A total of 12 pin-ended square sectional columns of 150 × 150 mm having a total height of 1400 mm were investigated. The considered variables were the steel tube diameters of 29, 58, and 76 mm and the load eccentricity (0, 50, and 150) mm. Accordingly, these columns were divided into three groups (four columns in each group) depending on the load eccentricity (e) to column depth (h) ratio (e/h = 0, 1/3, and 1). For each group, one column was solid (reference), and the other three columns contained steel tubes with hollow rat

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Publication Date
Tue Jan 01 2019
Journal Name
Journal Of Radiation Research And Applied Sciences
Determination of muon absorption coefficients in heavy metal elements
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Publication Date
Mon Jan 01 2018
Journal Name
African Journal Of Hospitality, Tourism And Leisure
An analytical study of the strategic flexibility variation as a function of the dynamic capabilities based on supply chain management (Case study: The General Petroleum Products Distribution Company in Baghdad)
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Publication Date
Thu Nov 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
The Reflection of self competency of the managers in their behavior
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Abstract

      This research aims to measure the effect of Self competency of the Managers in their behavior from the view point of the working individual in the organization since the behavior of managers is considered to be one of the essential variables in the organization which can affect the performance and the commitment of the working individual. the questioners was used to gather the data and the Iraqi Rail Road co. was the field of the study . and a random sample of (36) individual of the subordinates of the managers society of the study and used the (SPSS) statistical program was used in the analysis of the data of the research . the findings refer to the existence of a

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