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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 Sep 30 2022
Journal Name
Journal Of Economics And Administrative Sciences
The role of GRI standards in reporting the dimensions of sustainable development - An applied study in a number of local companies on the Iraq Stock Exchange
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The current research aims to shed light on the Global Reporting Initiative (GRI), which helps to report financial and non-financial information by economic units in general and listed on the Iraq Stock Exchange in particular. The research was based on a main premise that apply the criteria of the Global Reporting Initiative (GRI) would provide useful information to users to help them make appropriate decisions. To achieve the goal of the research, the descriptive analysis method was used, and quantitative analysis was used. At the level of the descriptive analysis method, a desk survey was conducted. As for the quantitative analysis, it relied on applied data through a questionnaire form (Questioners) as a research tool, and the

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Publication Date
Sun Oct 01 2017
Journal Name
Iecon 2017 - 43rd Annual Conference Of The Ieee Industrial Electronics Society
Optimal second order integral sliding mode control for a flexible joint robot manipulator
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The flexible joint robot manipulators provide various benefits, but also present many control challenges such as nonlinearities, strong coupling, vibration, etc. This paper proposes optimal second order integral sliding mode control (OSOISMC) for a single link flexible joint manipulator to achieve robust and smooth performance. Firstly, the integral sliding mode control is designed, which consists of a linear quadratic regulator (LQR) as a nominal control, and switching control. This control guarantees the system robustness for the entire process. Then, a nonsingularterminal sliding surface is added to give a second order integral sliding mode control (SOISMC), which reduces chartering effect and gives the finite time convergence as well. S

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Publication Date
Tue Nov 01 2016
Journal Name
2016 International Conference On Advanced Mechatronic Systems (icamechs)
Hierarchical sliding mode control applied to a single-link flexible joint robot manipulator
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Trajectory tracking and vibration suppression are essential objectives in a flexible joint manipulator control. The flexible joint manipulator is an under-actuated system, in which the number of control actions is less than the degree of freedom to be controlled. It is very challenging to control the underactuated nonlinear system with two degree of freedom. This paper presents a hierarchical sliding mode control (HSMC) for a rotary flexible joint manipulator (RFJM). Firstly, the rotary flexible joint manipulator is modeled by two subsystems. Secondly, the sliding surfaces for both subsystems are constructed. Finally, the control action is designed based on the Lyapunov function. Computer simulation results demonstrate the effectiveness of

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Publication Date
Sat Feb 03 2018
Journal Name
Chinese Journal Of Physics
A true random number generator based on the photon arrival time registered in a coincidence window between two single-photon counting modules
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True random number generators are essential components for communications to be conconfidentially secured. In this paper a new method is proposed to generate random sequences of numbers based on the difference of the arrival times of photons detected in a coincidence window between two single-photon counting modules

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Publication Date
Sat Jan 01 2022
Journal Name
Proceeding Of The 1st International Conference On Advanced Research In Pure And Applied Science (icarpas2021): Third Annual Conference Of Al-muthanna University/college Of Science
A theoretical study including the breakdown voltage characteristics for some industrial gases
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Industrial characteristics calculations concentrated on the physical properties for break down voltage in sf6, cf4 gases and their mixture with different concentrations are presented in our work. Calculations are achieved by using an improved modern code simulated on windows technique. Our results give rise to a compatible agreement with the other experimental published data.

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Publication Date
Tue Jan 08 2019
Journal Name
International Journal Of Mechanical Engineering And Technology (ijmet)
MANUFACTURING AND ANALYSIS CUSTOM FOOT ORTHOTIC FOR FLEXIBLE FLATFOOT
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This paper presents two main parts: The first part involves manufacturing the specimens form composite material for mechanical testing (tensile, flexural and fatigue tests), then design a custom foot orthesis (CFO) and manufacturing from composite lamination (3nylglass 2carbon fiber 3nylglass) for patient suffer from flexible flat foot since birth and over-pronation. The second part of this research involves a design a model of custom foot orthesis in (solid work 2018) and then analysis of custom foot orthosis in engineering analysis program (ANSYS V.18.2).The applied pressure in boundary condition adopted from Force Sensor Resistance (FSR 402 ) in various regions in foot after wearing composite CFO. Used a composite materials in engineerin

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Publication Date
Wed Jul 01 2026
Journal Name
Iranian Journal Of Veterinary Medicine
The Role of Melatonin in Thyroid Function in Adult Rats
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Background: The thyroid gland, a vital endocrine organ, the thyroid gland synthesizes and secretes hormones, such as triiodothyronine (T3), thyroxine (T4), and calcitonin. The pineal gland produces and releases melatonin, which is stimulated in the dark and suppressed in the presence of light. Objectives: This study aimed to assess how melatonin influences adult male rats’ thyroid performance.Methods: Eighteen adults male Wistar albino rats (Rattus norvegicus) (approximately 12-14 weeks old and weighing 220±10 g) were randomly divided into three groups, each containing six rats, and were treated for 30 days as follows: The control group (A) received distilled water (DW). The A1 group received 10 mg/kg body weight (B.W.) of melatonin oral

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Publication Date
Sun Dec 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
Analysis The Consistency Between The Tariff And The Exchange Rate And Their Reflection On The Trade Balance In Iraq
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       The trade balance is considered as a way to join the national economy with the world, So it is the mirror that reflect the economic center of the country and it is point to competitive ability of it, The tariff and the exchange rate perform a great role to motivate the domestic production and improve the trade balance if we direct them to achieve the same purpose. The Iraqi economic has trade balance which achieve overabundant during the years of studying because of the oil exports, while the other exports represent a small percentage it is hardly remember, and expansion in imports from other side causes exhaustion in oil revenues, and this make the trade balance in permanent

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Publication Date
Thu Apr 25 2019
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
The Correlation between the Dimensions of Organizational Silence and the F Function Life an Exploratory Study of the Views of a Sample of Workers in the Health Center / Sulaykh: The Correlation between the Dimensions of Organizational Silence and the F Function Life an Exploratory Study of the Views of a Sample of Workers in the Health Center / Sulaykh
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The research aims to test the effect of the behavioral factors (intangible) represented by an explanatory variable represented by organizational silence and a responsive variable of quality of Function life. The problem was the negative effects of the organizational silence on the morale of the employees and consequently their performance and the quality of function life. To collect the data and information needed to measure the two variables of research conducted in the health center / Sulaikh by taking a sample of (40) employees to test the hypotheses of research through the survey of their views, using statistical tools non parametric using the program. The most important recommendations were the establishment of training workshops fo

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Publication Date
Wed Oct 17 2018
Journal Name
Journal Of Economics And Administrative Sciences
the role of marketing intelligence in promoting new product policies.a sample survey of workers in a number of mineral water plants in dohuk governorate
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Marketing Intelligence is one of the important methods of collecting information about competitors ' products and changes in customers ' tastes and needs that contribute to determining the policies to be followed in product development.

The problem of research, which seeks to be answered by the extent to which the companies in question have the appropriate and effective mechanisms to develop their products, and the nature of the relationship between the components of marketing intelligence and new product development policies. The importance of research is determined by the importance of obtaining important and necessary information to make the appropriate decision on the development of the new product an

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