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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
Thu Jan 16 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Security and confidentiality of information and its impact on the competitive performance of insurance companies: A prospective study for the Iraq insurance company and ALhamraa Insurance company (private)
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The security of information represent the available  protection of  information and its component and guaranty the its safety and confidentiality. The absent or lack or stop of security of information and without maximum benefit may lead to lose confidence and make it burden on the company. So we must protect the company and information from the damages which may lead to the frailer of performance and loses of the company and its workers. So the security of information considered one of the potential  and controlling basis to protect individuals and companies from the damages. To insure the security  and confidentiality of information there are delicate,  proper and trusted ways, like FIRE WALL, PASS WORD, SYPHAR

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Publication Date
Sun Oct 18 2026
Journal Name
Adab Al Rafidayn
Measuring the quality of office services using (LibQUAL + ®): the central library of the University of Baghdad as a model
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Libraries, information centers, and everything related to organizing and preparing information need to be periodically re-evaluated in order to stand on the level of quality, which means improving the general reality of these institutions to ensure sufficient satisfaction from beneficiaries of the services provided. This is what was worked on in this research, as one of the most important quality standards in libraries and information centers, LibQUAL+®, was applied in one of the most important and oldest central university libraries, namely the Central Library of the University of Baghdad at its two locations, Al-Jadriya and Al-Waziriya. The sample of beneficiaries to whom the questionnaire was distributed reached 75 beneficiaries distrib

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Publication Date
Tue Nov 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
Proposal of Using Principle of Maximizing Entropy of Generalized Gamma Distribution to Estimate the Survival probabilities of the
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Abstract

In this research we been estimated the survival function for data suffer from the disturbances and confusion of  Iraq Household Socio-Economic Survey: IHSES II 2012 , to data from a five-year age groups follow the distribution of the Generalized Gamma: GG. It had been used two methods for the purposes of estimating and fitting which is the way the Principle of Maximizing Entropy: POME, and method of booting to nonparametric smoothing function for Kernel, to overcome the mathematical problems plaguing integrals contained in this distribution in particular of the integration of the incomplete gamma function, along with the use of traditional way in which is the Maximum Likelihood: ML. Where the comparison on t

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Publication Date
Fri Dec 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
The role of Job description and Perceived organizational support to achieving An Excellent Job performance - An Exploratory study of the views of a sample of department heads at Sulaimaniyah University.
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     This research Sought to identify the correlation relationships and the impact of each of the job description and perceived organizational support, Excellent Job performance of the heads of academic departments in the faculties of the University of Sulaymaniyah Iraqi Kurdistan Region, totaling (89) as President, and to achieve this was Default plan includes research variables as well as the formulation of a number of preparation fundamental assumptions, and researchers used a questionnaire for this purpose as a tool head of the collection of data and information, as it was distributed (80) copies, and the number of retrieved them (76) a copy of a valid statistical analysis, as well as conducting personal i

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Publication Date
Tue Dec 30 2014
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Influences of Operating Variables on Hydrodynamic Performance of Plunging Water Jet Downflow Bubble Column
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The hydrodynamics of a co-current down flow bubble column has been investigated with air – water system. A Perspex bubble column of 5cm in diameter and 1.5m height is used as a test contactor using nozzles of 7, 8 and 9 mm diameter for air-water distributing. The column is provided with three electro-resistivity needle probes for bubble detection.
Experimental work is carried out with air flow rates from 0.09 to 0.45 m3/hr and liquid flow rates from 0.65 to 1.1m3/hr in order to study the effects of superficial gas velocity, nozzle diameter and liquid flow rate on the characteristics of hydrodynamic interactions viz. gas hold up, bubble diameter and bubble velocity by using two technical methods, direct height measurements for air-wa

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Publication Date
Mon Jan 01 1990
Journal Name
Solar & Wind Technology
Use of passive heat transfer and fluorescence to improve performance of photovoltaic solar panels
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Publication Date
Mon Mar 15 2010
Journal Name
International Journal Of Poultry Science
Effect of Supplementing Different Levels of Chromium Yeast to Diet on Broiler Chickens Performance
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The experiment was conducted at the Faculty of Agriculture University of Ain Shams-Egypt, from January to March 2008, to study the effect of different levels of chromium yeast (Cr-yeast) on broiler chickens performance, carcass quality and enzyme activity through 35 days of experimental periods. A total of 450 one-day old unsexed chickens (Cobb) strain were used. The birds were randomly allocated to five treatments with 3 replicates each. The treatments were control (T1) without supplementation and T2, T3, T4 and T5 which were supplemented with 0.5, 1, 1.5 and 2 mg Cr-yeast /kg diet, respectively. Live body weight and weight gain were significantly (p<0.05) higher when Cr-yeast were supplemented at 1 (T3), 1.5 (T4) and 2 (T5) mg/kg diet. Fe

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Publication Date
Thu Apr 15 2010
Journal Name
International Journal Of Poultry Science
Effect of Dietary Supplementation with Different Oils on Productive and Reproductive Performance of Quail
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Publication Date
Sat Oct 01 2022
Journal Name
Inorganic Chemistry Communications
Investigation of performance and efficiency of donor-π-bridge-acceptor based material solar cell
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The novel groups of organic chromophores containing triphenylamine (TPA) (ATP-I to ATP-IV) have been constructed by structural modification of electron donors with substitution biphenyl and bipyridine rings inserting a π-linkage. Density functional theory (DFT) and time-dependent type of it (TD-DFT) have been operated to study results of donating ability of TPA and spacer on absorption, geometrical, photovoltaic, and energetic attributes of these sensitizers. Structural attributes have been revealed that incorporation of TPA, acceptor and π bridge include a perfect coplanar conformation in TPA-III. Based on frequency computations and ground-state optimization, bandgap (Eg) energy, ELUMO, EHOMO have been determined. For enlightening maximu

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Publication Date
Sat Mar 01 2025
Journal Name
Wasit Journal Of Engineering Sciences
Impact of Substrate Dielectric Constant on Performance of 2.4 GHz Microstrip Patch Antenna Array
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In recent years, arrays have been widely used in many applications, especially those applications that need high guidance, whether in military, medical, or other applications. Arrays are highly oriental, unlike single antennas.  In this work, we analyze the effect of the insulating substrate insulation constant on the 2X2 microstrip patch antenna array at a frequency of 2.4 GHz, which is suitable for WLAN applications. CST Microwave Studio Version 2019 was used to design, simulate, and analyze the proposed model. The bar line feeding technique was used to feed the array. A set of mathematical relationships was used to calculate the dimensions of the array. We simulated and analyzed the array on three dielectric pillars: (FR-4) with

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