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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
Fri Apr 01 2022
Journal Name
Journal Of Engineering
Improvement of Diesel Fuel Engine Performance by Nanoparticles Additives
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This study was done to investigate the impact of different nanoparticles on diesel fuel characteristics, Iraqi diesel fuel was supplied from al-Dura refinery and was treated to enhance performance by improving its characteristics. Two types of nanoparticles were mixed with Iraqi diesel fuel at various weight fractions of 30, 60, 90, and 120 ppm. The diesel engine was tested and run at a constant speed of 1600 rpm to examine and evaluate the engine's performance and determine emissions. In general, ZnO additives' performance analysis showed they are more efficient for diesel fuel engines than CeO. The performance of engine diesel fuel tests showed that the weight fraction of nanoparticles at 90 and 120 ppm give a similar

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Publication Date
Thu May 11 2023
Journal Name
Engineering Applications Of Computational Fluid Mechanics
Photovoltaic-thermal system combined with wavy tubes, twisted tape inserts and a novel coolant fluid: energy and exergy analysis
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To create a highly efficient photovoltaic-thermal (PV-T) system and maximise the energy and exergy efficiency, this study aims to propose an innovative configuration of a PV-T system comprising wavy tubes with twisted-tape inserts. Following the validation of a numerical model, a parametric study has been conducted to assess the geometrical effects of twisted tape and wavy tubes, as well as the coolant fluid type and velocity, on the overall performance of a PV-T system, located in Shiraz, Iran. It is found that employing twisted tape improves the energy and exergy efficiency by approx. 6.3%. The best configuration yields 12.4% and 16.8% increase in energy and exergy efficiency compared to conventional PV systems. This is achieved at 15% vo

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Publication Date
Tue Feb 12 2019
Journal Name
Iraqi Journal Of Physics
Laser wavelength and energy effect on optical and structure properties for nano titanium oxide prepared by pulsed laser deposit
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Nano TiO2 thin films on glass substrates were prepared at a constant temperature of (373 K) and base vacuum (10-3 mbar), by pulsed laser deposition (PLD) using Nd:YAG laser at 1064 nm wavelength. The effects of different laser energies between (700-1000)mJ on the properties of TiO2 films was investigated. TiO2 thin films were characterized by X-ray diffraction (XRD) measurements have shown that the polycrystalline TiO2 prepared at laser energy 1000 mJ. Preparation also includes optical transmittance and absorption measurements as well as measuring the uniformity of the surface of these films. Optimum parameters have been identified for the growth of high-quality TiO2 films

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Publication Date
Sun May 04 2014
Journal Name
Journal Of Physical Education
The effect of developing the strength of the muscles of the arms and shoulders in developing the performance of some floor movements skills in artistic gymnastics for women
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Publication Date
Sun Jan 05 2020
Journal Name
Annals Of Tropical Medicine And Public Health
THE EFFECT OF THE TRAINING CURRICULUM ON DEVELOPING KINETIC AND TRANSITIONAL RESPONSE SPEED, ACCURACY OF THE STOPPING WALL PERFORMANCE, AND DEFENDING THE STADIUM IN VOLLEYBALL
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Publication Date
Sun Mar 28 2021
Journal Name
Journal Of The College Of Education For Women
The Effectiveness of a Structural Theory- based Training Program in Enhancing Arabic Language Teachers’ Teaching Practices and their Tendencies towards Structural Teaching: مريم بنت حسن البلوشي، ريا بنت سالم المنذري، علي مهدي كاظم
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The study aims to identify the effectiveness of a structural theory-based training program in enhancing the teaching practices of Arabic language teachers teaching grade ten in South Al Batinah in Sultanate of Oman. The study used the quasi-experimental design, and the sample consisted of 40 male and female teachers. To achieve the objectives of the study, a training program, an observation form and a measurement tool of teachers’ tendencies towards a structural teaching were made. The program was implemented with an experimental group of 20 female and male teachers in the first semester of the academic year 2018/2019. The study has found that there is a statistically significant difference between the average grades before and after i

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Publication Date
Fri Jul 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
The role of the Organizational Service Orientation practices and its Impact in inhancing the employees performance (A Fiald Research in Baghdad Municipality)
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Abstract:

Recently, there is a widespread attention about the service at the level of each of the research and academic studies, and at the organizational level as well. The subject of orientation towards the service aspect is starting to be of this attention being of the modern subjects, relatively, which appeared at the end of the last century, as well as the link of this subject with the relationship between the organization and its customers, and how to provide high quality services to get their satisfaction. Thus, the specialists from researchers were interested in this field to develop an appropriate scale to measure the organizational orientation toward service, and it was the most prominen

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Publication Date
Mon Nov 15 2021
Journal Name
Studies Of Applied Economics
The Role of Market-Share Management Strategies in Explaining the Stocks Performance Variance of a Number of Industrial Companies- An Analytical Research
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The study aims to know the nature of the expected relationship between market share management strategies and the variation in the performance of the shares of a number of Iraqi industrial companies listed in the Iraqi Stock Exchange. For the period (2005-2018) in the light of both the monthly closing prices and sales volume during the research period, the (Panel Data) method was relied on through a stylistic test (fixed effects model and random effects model), and the results determined the need to adopt the fixed effects model method for sample data and test Assumptions, the results showed the positive impact of market share according to its strategies on the performance of stocks according to its studied indicators (Treynor index

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Publication Date
Tue Dec 01 2009
Journal Name
Journal Of Economics And Administrative Sciences
The role of knowledge management in achieving outstanding university performance (Applied study in the Faculty of Management and Economics / University of Kufa)
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The research aims to determine the role of knowledge management to measure performance on a sample of faculties of Administration and Economics the University of Kufa, and to achieve this goal through a researcher from the theoretical literature and research and studies related to the construction of the scheme shows the hypothetical relationship between the variables, which was adopted by the independent variable knowledge management, distributed four variables are: (knowledge generation, knowledge storage, knowledge dissemination, the application of knowledge), as well as four variables representing the variables adopted for the performance of the university are:
(to reduce costs and increase profits, improve quality, scie

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Publication Date
Thu Jun 22 2017
Journal Name
Research Journal Of Pharmaceutical, Biological And Chemical Sciences
Testing the Efficiency of Probiotic in Reducing the Growth of Aspergillus flavas in Corn Stored and its Effect on Performance of Broiler
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This study has been done for testing the effectiveness and efficiency of probiotic in its ability to inhibit Aspergillus flavus , which secretes the aflatoxin B1 and compare it with materials that were approved to be effective in the inhibition of the growth of fungi and break down and reduction of mycotoxin. these are the filax substance and ozone gas. A laboratory experiment has been conducted to determine the isolates out of the fungus producing the aflatoxin B1.the isolate producing aflatoxin B1 has grown on the yellow corn seed. the probiotic was added along with the filax and they have been exposed to ozone gas and then they were stored from 30 days. A bio test was con conducted to knw the effects of biological toxin on the broiler me

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