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Enhancing the Performance of Piezoelectric Energy Harvesters Using Permanent Magnets
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A cantilevered piezoelectric beam with a tip mass at its free end is a common energy harvester configuration. This paper introduces a new principle of designing such a harvester which increases the generated voltage without changing the natural frequency of the harvester: The attraction force between two permanent magnets is used to add stiffness to the system. This magnetic stiffening counters the effect of the tip mass on the natural frequency. Three setups incorporating piezoelectric bimorph cantilevers of the same type in different mechanical configurations are compared theoretically and experimentally to investigate the feasibility of this principle. Theoretical and experimental results show that magnetically stiffened harvesters have important advantages over conventional setups. They generate more voltage and they can be tuned across a wide range of excitation frequencies.

 

 

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Publication Date
Mon Jun 01 2009
Journal Name
Al-khwarizmi Engineering Journal
Study the Effect Different Radioactive Dose on Mechanical Properties of Composite Material from Novolak Resin Exposure to High – Energy Radiation
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The research involves using phenol – formaldehyde (Novolak) resin as matrix for making composite material, while glass fiber type (E) was used as reinforcing materials. The specimen of the composite material is reinforced with (60%) ratio of glass fiber.

      The impregnation method is used in test sample preparation, using molding by pressure presses.

      All samples were exposure to (Co60) gamma rays of an average energy (2.5)Mev. The total doses were (208, 312 and 728) KGy.

      The mechanical tests (bending, bending strength, shear force, impact strength and surface indentation) were performed on un irradiated and irrad

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Publication Date
Fri Apr 12 2019
Journal Name
Journal Of Economics And Administrative Sciences
Core competencies and Their Role in Enhancing Organizational flexibility: An Analytical Study of the Views of a Sample of Employees in Presidency University of Mosul
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Abstract

The study aims to identify the levels of core competencies dimensions and types of organizational flexibility in the investigated organization, as well as to determine the nature of the relationship and the impact of core competencies dimensions with the process of organizational flexibility. Thus, a number of research questions were presented to express the research problem as follows:

  • What is the level of the investigated individuals' awareness to core competencies and organizational flexibility across their dimensions and types in the investigated organization?
  • To what extent are core competencies and organizational flexibility available in the Organiz

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Publication Date
Tue Jun 01 2021
Journal Name
Iraqi Journal Of Physics
Influence of Laser Energy on the Structural and Optical Properties of (CdO):(CoO) Thin Films Produced by Laser-Induced Plasma (LIP)
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In this work, (CdO)1-x (CoO)x thin films were prepared on glass slides by laser-induced plasma using Nd:YAG laser with (λ=1064 nm) and duration (9 ns) at different laser energies (200-500 mJ) with ratio (x=0.5), The influence of laser energy on structural and optical properties has been studied. XRD patterns show the films have a structure of polycrystalline wurtzite. As for AFM tests results for the topography of the surface of the film, where the results showed that the grain size and the average roughness increase with increasing laser energy. The optical properties of all films were also studied and the results showed that the absorption coefficient for within the wavelength range (280-1100 nm), The value of the optical power gap fo

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Publication Date
Wed Aug 01 2012
Journal Name
مجلة دراسات عربية في التربية وعلم النفس
Concepts of renewable energy among students at the Ibn Al-Haytham College of Education and its relationship to their environmental awareness
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Publication Date
Thu Sep 01 2011
Journal Name
Journal Of Economics And Administrative Sciences
The influence of the personal values of the workers in the performance of the work teams
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The research aims to know the impact of workers values on their performance which is reflected on increasing productivity and improving its quality as well as the organization's progress and success.  Application of this research took place in the General Company Of Electrical Industries; it contained four main pillars; the first involved research methodology، regarding the problem، importance، aim، basic theory، and method of data collection، the second is dedicated to the theoretical framework related to the research basic variables (values and workgroups) the third is assigned to analyze the actual data by using number of statistical methods، such as mathematical medium and standard deviation and also spearman rank

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Publication Date
Sat Feb 02 2019
Journal Name
Journal Of The College Of Education For Women
The use of ionic pumping method for improving the performance of vacuum micro-electronic valves: The use of ionic pumping method for improving the performance of vacuum micro-electronic valves
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Abstract
The use of electronic valves is commonly available. yet, the most
common is the techniques of communications as prod casting transmitter that
are used by these valves in addition to their use in communication tools as far
distance telephone, electronic measuring techniques , and others.
In this study, an attempt is endeavored for improving the efficiency of the
vacuum micro- valves(GI-19b) through activating their internal surfaces by the
use of ionic pumping which is used for treating valves which are out of order
(because of sedimentation some materials and oxide on its poles). The
existence of these materials and oxide increase the sum of current leakage
moving in between. The use of ionic pumpin

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Publication Date
Thu Mar 21 2024
Journal Name
International Development Planning Review
THE EFFECT OF USING A DISABLING FORCE TRAINING TOOL ON WALKING PERFORMANCE: AN ANALYTICAL STUDY OF TIME AND STEP LENGTH IN THE 20 KM WALKING RACE EVENT FOR APPLICANTS
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Publication Date
Mon Sep 29 2025
Journal Name
Iraqi Journal Of Agricultural Sciences
STUDY THE EFFECTS OF SOME MECHANICAL FACTORS ON THE PERFORMANCE OF THE HAMMER MILL
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Publication Date
Thu Mar 17 2016
Journal Name
International Journal Of Computer Applications
Analysis of Wind Speed Data and Annual Energy Potential at Three locations in Iraq
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Publication Date
Wed Feb 20 2019
Journal Name
Iraqi Journal Of Physics
Theoretical spectroscopic studies of potential energy curves and Fortran parabola for beryllium oxide molecule
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    Theoretical spectroscopic  studies of  beryllium oxide has been  carried out, potential energy curves for ground states X1Σ+ and exited states A1Π , B1Σ+ by using two functions Morse and  and Varshni compared with experimental results. The potentials of this molecule are agreement with experimental results. The Fortrat Parabola corrcponding to  and branches were determind in the range 1<J<20 for the (0-0) band. It was found that for electronic transition  A1Π- X1Σ+  the bands head lies in  branche of  Fortrat p

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