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Enhancing the Performance of Piezoelectric Energy Harvesters Using Permanent Magnets

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
Sun Jan 07 2024
Journal Name
Migration Letters
The Effect Of Preventive Physical Exercises Supported By Collagen Supplements And Vitamin D In Improving Some Of The Physical And Skill Abilities Of Handball Players

The purpose of this paper is to preparing preventive exercises supported by collagen supplements and vitamin D for handball players, and identify the effect of preventive physical exercises supported by collagen supplements and vitamin D on some physical and skill abilities of handball players. The researchers used the experimental method and designed two groups, one experimental and the other control, with both pre- and post-tests, to suit the nature of the research. The research community was selected from handball players (specialized school players), numbering (14), and they were divided into two groups, each group numbering (7) players. One of the most important results reached by the researcher is that: The exercises prepared by the r

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Publication Date
Wed Nov 20 2024
Journal Name
Journal Of Baghdad College Of Dentistry
An evaluation of the influence of different finishing lines on the fracture strength of full contour zirconia CAD/CAM and heat press all-ceramic crowns

ABSTRACT Background: One of the major problems of all ceramic restorations is their probable fracture against the occlusal forces. The objective of this in vitro study was to evaluate the effect of two gingival finishing lines (90°shoulder and deep chamfer) on the fracture resistance of full contour CAD/CAM and heat press all-ceramic crowns. Materials and Methods: Thirty two maxillary first premolars were prepared to receive full contour CAD/CAM (zolid) and heat press (Cergo Kiss) ceramic crowns using a special paralleling device (Parallel-A-Prep). The teeth were divided into four groups according to the type of finishing line prepared. Each crown was cemented to its corresponding tooth using self-etch, self-adhesive dual cure resin ceme

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Publication Date
Sun Jul 01 2007
Journal Name
Journal Of The Faculty Of Medicine Baghdad
A Comparison between Topical application of Calcipotriene, Clobetasol and a combination regime of the two drugs in the treatment of Iraqi Patients with Psoriasis Vulgaris

Back ground: Psoriasis is a chronic relapsing disorder with no life long cure, many systemic and topical modalities are available, one of these topical modalities is the vitamin D analogue
(calcipotriene) which is widely used recently to treat psoriasis and many other skin problems.
Aim of the study: Is to compare the safety, the efficacy and the tolerability of tolerability of topical calcipotriene, topical clobetasol and both of them in combination in treating Iraqi patients with psoriasis vulgaris. (The first study in Iraq that uses calcipotriene ointment in treating psoriasis and comparing it with other known topical treatments that were commonly used to treat this problem).
Patients and methods A to

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Crossref
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Publication Date
Wed Jan 01 2020
Journal Name
Plant Archives
The effect of adding nano concentrations of hydrogen peroxide to the diluted semen of iraqi local roosters on some laboratory characteristics after cooling and cryopreservation

This study was conducted at the poultry farm located in the College of Agricultural Engineering Sciences, University of Baghdad, Abu Gharib (the old site), and laboratories of the Animal Production Department, Jadriya, to investigate the effect of adding hydrogen peroxide H2O2 at nanoscale levels to semen diluents of local roosters sperm in a number of semen characteristics. In this study, 80 roosters local Iraqi chickens were used, the roosters were trained three times a week, to collect semen, until the largest number of them responded. Then the best 40 of the roosters were elected for the purpose of collecting the semen with a pooled sample, and then the samples were diluted and divided equally into four parts. The concentrations of 0, 1

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Scopus
Publication Date
Sun Jul 29 2018
Journal Name
Iraqi Journal Of Science
Assessing the Effects of Al- Rasheed Electrical Power Plant on the Quality of Tigris River, Southern of Baghdad by Canadian Water Quality Index (CCME WQI)

This study was conducted to investigate the effects of Al-Rasheed power plant (RPP) effluents at Al-Zafaraniya city on the physical – chemical of the Tigris River by using Canadian Water Quality Index(CCME WQI).Water samples were taken  monthly at four positions  and 11parameters were analyzed . The results of this study conducted that there was a significant impact of the RPP effluents on increase of water temperature, turbidity and electrical conductivity, and there was an increase in the phosphate concentration and water hardness at station 2 and the model classified water of Tigris river as poor in winter and fair to marginal in rest season for drinking and aquatic life

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Publication Date
Tue Dec 31 2019
Journal Name
Journal Of Economics And Administrative Sciences
The quality of work-life and relation to organizational excellence at King Khalid University of the faculty members' point of view / Business School Case study

This study aimed to identify the quality of the career path and its relation to organizational excellence at King Khalid University in the Faculty of Business from the point of view of the faculty members by identifying the dimensions quality of work-life including (participation of decision making, training and development opportunities, and the balance between personal and work life, and to identify the level of organizational excellence through dimensions ( Excellence of leadership, excellence of the  strategy, and excellence of organizational culture). The descriptive approach was used. The questionnaire was a research tool. It consisted of (29) paragraphs, distributed to the entire study community and then received 127

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Publication Date
Fri Mar 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
Measure and evaluate the return and risk formulas of Islamic Finance: Empirical study of the state of Jordan Islamic Bank and Islamic Arab International Bank

    The study aims to measure and evaluate the return and the risk formulas of Islamic finance of Jordan during the period (2000 – 2009) according of increasing  importance of these banks in recent and coming years to face challenges to maximize returns and minimize risks through financing with  Islamic formula to investigate of existence statistical significant  relationship between returns and risking Islamic bank , has been use of financial other statistical  measurement. Measuring return and risk of Islamic banks have not been widely considered ,except in few descriptive studies . The controversy among academic and professionals about hot to measure and evaluate a comprehe

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Publication Date
Sat Dec 31 2022
Journal Name
Journal Of Economics And Administrative Sciences
The Impact of Management by Walking Around on the Strategic Renewal of Business Organizations (Field Research in a Sample of Excellent grade hotels - in Baghdad)

This work aims to show the nature of the relationship between management by walking around  (the independent variable) and strategic renewal (the dependent variable), as well as it shows the effect of the independent variable on the dependent variable. Questionnaire items were considered the main tool for data collection by three basic aspects. The first involved the personal data of the respondents, while the second included items related to management by walking in five dimensions, and the third is strategic renewal items by addressing four dimensions. The tourism sector, while the community has six Excellent grade hotels was taken into account in this wor

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Publication Date
Tue Oct 01 2013
Journal Name
Journal Of Economics And Administrative Sciences
The relation between the governmental consumption expenditure and the economic growth in Iraq for the period 1981-2006

ABSTRACT

        The research aim is to determine the relation between governmental consumption expenditure (GCE) & GDP in Iraq for the period 1981-2006.

The research has determined the scale of optimization for (GCE) & try to know the extent productivity of this expenditure and using the long run &short run model to test .The results clarify the following

1-The marginal productivity for the (GCE) is positive so it is productive.

2-The (GCE) in Iraq is too high because the marginal productivity for the expenditure less than 1.

3- The (GCE) percentage to GNP is

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Publication Date
Sat Feb 02 2019
Journal Name
Journal Of The College Of Education For Women
The Christian Taghlib tribe in the first century A.H: The Christian Taghlib tribe in the first century A.H

Abstract:
Taghlib tribe had an important part in the history of the first century of
hijra. She managed to get the best social, economic and political basis in the
Arab- Islamic state. In this basis Taghlib was the best Dhimies in the Islamic
state. This tribe refused to be among the people of the book, and to be from
the people of dhima. That tribe refused to pay the Jizya and Khraj, but
accepted to pay double Sadaqa in stead of Jizya and Khraj, so in that case
many Muslims become angry.
Although their Christianity was naïve and simple, Taghlib hold it until the
end of the third century A.H. Taghlib did so because her people wanted to
keep their good relation with the Byzantine. Taghlib thought that the

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