Browsing by Author "Yehia, H. M."

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    Acoustic Energy Conversion into Useful Electric Energy from Disk Jockey by Using Piezoelectric Ttransducers
    (IEEE, 2016) Selim, Kyrillos K.; Haggag, Ayman; Yehia, H. M.; Amer, Fathy Z.; El-Garhy, Ahmed M.
    In this study a new noise source is proposed as a one of renewable energy sources in energy harvesting. Disk Jokey (DJ) is a common device in celebrations and other events. Converting the produced noise from DJ to electric energy by using a suitable piezoelectric transducer is the main aim of this study. Piezoelectric sensors are used to convert the sound waves to electric charges. Piezoelectric sensor of the model 7BB-41-2 is used in this study. The piezoelectric sensors are connected in series, parallel, and hybrid combination connections. The disk jockey is used as an acoustic noise source. The sound intensity levels of the output sound are 81, 84, 87 dB. The output of the three connection modes are measured at 0, 1,2,3,4, and 5cm distance. The results showed that the parallel connection gave the highest power at the various distances. The maximum generated power is 4.96m watts without using an external power supply for the signal condition device. The power decreases by increasing the distance from the source of the noise.
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    Effect of diamond additions on the microstructure, physical and mechanical properties of WC- TiC- Co/Ni Nano-composite
    (ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND, 2018-02) Yehia, H. M.; El-Kady, Omayma; Abu-Oqail, Ahmed
    WC- TiC- Co- Ni/diamond composites have been prepared by powder metallurgy technique. 2.5%, 5%, 7.5% and 10 wt% diamond were added. WC- TiC- Co/diamond was coated with 12 wt% nickel by the electro-less deposition process. All the samples were compressed at 700 MPa then sintered at 1450 for 1 h. XRD, EDAX, and microstructure were investigated. Density, electrical resistivity, thermal conductivity, magnetic properties, the coefficient of thermal expansion, fracture toughness and hardness were studied. The results of XRD and EDAX analysis show that new phases were formed. It also revealed that the diamond content has a positive effect on the thermal properties of composites. Presence of Ni content improves the Fracture toughness of the composites but decreases the hardness.