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Item type:Publication, A Comparative Study of the Electrical Characteristics of Piezoelectric and Triboelectric Nanogenerators for Energy-Harvesting Floor Tiles(2020-06-01) ;Yingyong, Phonexai ;Thainiramit, Panu ;Nundrakwang, Songmoung ;Janphuang, PattanaphongIsarakorn, DonPiezoelectric and Triboelectric nanogenerators (PENG and TENG) have gained significant attention for use in self-powered electronics and sensing systems. They also have high potential to harvest energy from low-frequency vibration sources in the ambient environment. This paper investigated the performance and behavior of the two aforementioned nanogenerators based on energy-harvesting floor tiles by using a test bench to demonstrate the electrical characteristics output and comparing their power density output, energy density output, and other properties for characterization and scale-up in practical applications. The input used in the experiment varied the gap distance of the cover plate for the test bench with constant pneumatic pressure to excite the cover plate. The experimental results showed that the power density and energy density of PENG were higher than those of the TENG. The power density and energy density measured in 10 s under 2 Hz of input excitation of PENG and TENG at the gap width of 5 mm were 5773.35 μW/cm3, 1376.26 μJ/cm3 and 752.34 μW/cm3, 31.32 μJ/cm3, respectively. Due to their high output density, they enable promising possibilities to power small consumption electronics and sensing systems. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Design and evaluation of double-stage energy harvesting floor tile(2019-10-01) ;Isarakorn, Don ;Jayasvasti, Subhawat ;Panthongsy, Phosy ;Janphuang, PattanaphongHamamoto, KazuhikoThis paper introduces the design and characterization of a double-stage energy harvesting floor tile that uses a piezoelectric cantilever to generate electricity from human footsteps. A frequency up-conversion principle, in the form of an overshooting piezoelectric cantilever, plucked with a proof mass is utilized to increase energy conversion efficiency. The overshoot of the proof mass is implemented by a mechanical impact between a moving cover plate and a stopper to prevent damage to the plucked piezoelectric element. In an experiment, the piezoelectric cantilever of a floor tile prototype was excited by a pneumatic actuator that simulated human footsteps. The key parameters affecting the electrical power and energy outputs were investigated by actuating the prototype with a few kinds of excitation input. It was found that, when actuated by a single simulated footstep, the prototype was able to produce electrical power and energy in two stages. The cantilever resonated at a frequency of 14.08 Hz. The output electricity was directly proportional to the acceleration of the moving cover plate and the gap between the cover plate and the stopper. An average power of 0.82 mW and a total energy of 2.40 mJ were obtained at an acceleration of 0.93 g and a gap of 4 mm. The prototype had a simple structure and was able to operate over a wide range of frequencies. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Performance and behavior analysis of piezoelectric energy harvesting floor tiles(2019-07-01) ;Panthongsy, Phosy ;Isarakorn, Don ;Hamamoto, KazuhikoJanphuang, PattanaphongThis paper presents the performance and behavior analysis of two unlike piezoelectric energy harvesting floor tiles in which they are functioned with different frequency up-conversion strategies to achieve the high energy conversion efficiency from low and variable-frequency vibration as the human footstep. One of such strategies is to convert the frequency of piezoelectric bimorph up through the magnetic interaction between a permanent magnet and an iron plate, while another one is achieved on that through the mechanical impact between a cover plate and a wall of the floor tile. Experimentally, the floor tiles having one piezoelectric bimorph inside of them are prototyped and then mounted to their individual input-exciting kit to investigate the energy harvesting performance. The input-exciting kits are employed to simulate the human footstep on floor tiles. The results show that the floor tile with frequency up-converting mechanism based on mechanical impact should be a better option for energy harvesting from human footstep due to the low-profile structure and good energy harvesting performance. Moreover, its operational way can result in long-lasting piezoelectric bimorph. When a cover plate is actuated to move down with the velocity of 54.13 mm/s and then released, the floor tile can produce the average power of 0.82 mW at load resistance approximately of 55.68 kΩ. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Fabrication and evaluation of energy harvesting floor using piezoelectric frequency up-converting mechanism(2018-08-15) ;Panthongsy, Phosy ;Isarakorn, Don ;Janphuang, PattanaphongHamamoto, KazuhikoThis paper reports on the fabrication and evaluation of an energy harvesting floor tile using unimorph PZT piezoelectric cantilevers to convert kinetic energy from human footsteps into usable electricity. The operation of the tile is based on frequency up-converting mechanism in which low frequency input vibrations are converted into high frequency vibrations of an electromechanical transduction. The operational frequency of the PZT unimorph cantilever was converted up by an interaction between a permanent magnet and an iron bar. Vertical displacement of the oscillating cantilever was localized with a stopper preventing damage to the piezoelectric layer from shock or over-displacement excitation. The magnetic field density between the magnet and the iron bar was investigated through finite element analysis simulation in order to define an optimal air gap. Experimentally, a unimorph PZT cantilever was initially prototyped to validate the design. The results showed a successful frequency up-conversion with a resonant frequency of 10.54 Hz. Then, it was scaled up by accommodating 24 unimorph PZT cantilevers followed by experimental validation to evaluate its energy harvesting performance. Each cantilever was connected to a full wave bridge rectifier then connected in parallel with the other cantilevers. The generated electrical power and energy were investigated through various resistive loads. The average power and total output energy produced by one foot step on the tile were found to be 1.24 mW and 3.49 mJ, respectively at an optimal load resistance of 74.44 kΩ. The energy conversion efficiency reached 17.12% demonstrating the potential of harvesting energy from human motion. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Polymer based microneedle patch fabricated using microinjection moulding(2018-08-14) ;Janphuang, Pattanaphong ;Laebua, Mongkhol ;Sriphung, Chanwut ;Taweewat, PhatsakonSirichalarmkul, AnanThis paper presents the development of a polymer based microneedle patch for transdermal drug delivery application using plastic microinjection moulding. Design and analysis of the microneedle cavities and mould insert used in the injection moulding process were carried out using Computer-Aided Engineering (CAE) software. A mould insert with low surface roughness was fabricated using Micro Electrical Discharge Machining (μ-EDM). The injection moulding parameters including clamping force, temperature, injection pressure and velocity were characterized in order to obtain the optimum reproducibility. Solid truncated cone microneedles, made of biocompatible polymethyl methacrylate (PMMA), with a round tip radius of 50 μm and 500 μm in height have been realized by microinjection moulding process demonstrating the potential of a low cost, high production efficiency, and suitable for mass production. In addition, a mould insert of cylindrical microneedles fabricated using X-ray LIGA has been proposed. - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Harvesting energy from a rotating gear using an AFM-Like MEMS piezoelectric frequency up-converting energy harvester(2015-06-01) ;Janphuang, Pattanaphong ;Lockhart, Robert A. ;Isarakorn, Don ;Henein, SimonBriand, DanickThis paper presents an analytical and experimental study of a compact configuration to harvest energy from a rotating gear using piezoelectric microelectromechanical system harvesters. The reported configuration realizes a contact-Type frequency up-conversion mechanism in order to generate useful electrical energy. The up-conversion mechanism was achieved using an atomic force microscope (AFM)-like piezoelectric cantilever plucked by the teeth of the rotating gear that could be eventually driven by an oscillating mass. This paper describes relevant design guidelines for harvesting energy from the low-frequency mechanical movement of a rotating gear through analytical modeling and finite element method (FEM) simulation followed by experimental validation. Different harvester configurations are investigated to identify the optimal configuration in terms of the output energy and energy conversion efficiency. The latter results are reported for the first time because of the implementation of an original concept based on the coupling of the harvester with a rotational flywheel. The experimental results reveal that free vibrations of the harvester after plucking contribute significantly to the output energy and efficiency. By adding a proof mass, the efficiency of the system can be greatly improved. For plucking speeds between 3 and 19 r/s, average output powers in the order of tens of microwatts were obtained for continuous plucking. By combining interaction energy, friction, and energy absorption, between the harvester and inertial mass, the maximum efficiency of the impact piezoelectric harvesters was found to be 1.4%. The efficiency results obtained were compared with the noncontact magnetic plucking approach further demonstrating the potential of our concept. Finally, different tip-gear materials combinations were evaluated showing the importance of their nature on the reliability of the presented configuration.
