scholarly journals Finger-powered electrophoretic transport of discrete droplets for portable digital microfluidics

Lab on a Chip ◽  
2016 ◽  
Vol 16 (13) ◽  
pp. 2521-2531 ◽  
Author(s):  
Cheng Peng ◽  
Yide Wang ◽  
Y. Sungtaek Ju

We demonstrate digital microfluidics based on finger-powered electrophoretic transport of aqueous droplets immersed in dielectric oil. The electrodes are biased by converting mechanical energy into electrical energy using an array of piezoelectric elements.

Author(s):  
Jahangir Rastegar ◽  
Richard Murray

This is a review of two patents relating to electrical power generation on-board gun-fired munitions. The devices harvest mechanical energy from the motion of the projectile (e.g. the axial firing acceleration), and then convert the energy from mechanical to electrical using novel mechanisms and materials such as piezoelectric elements. The devices are particularly important for several reasons. Firstly, the devices are inherently safe because the root source of the electrical energy is the motion of the projectile; therefore no electrical energy can be produced until after the projectile is fired. Second, the devices have a much longer shelf-life than competing electrical power sources such as batteries. Finally, the devices are simple, rugged, and reliable making them ideal for the harsh environment on-board gun-fired projectiles. In addition to presenting the general approach, the logical framework of the patented embodiments is presented, especially with respect to the types of motion used for harvesting and the challenges presented by the varied magnitudes of those motions in different weapon platforms.


Author(s):  
Jahangir Rastegar ◽  
Richard Murray

Piezoelectric-based energy harvesting power sources that employ spring-mass vibrating systems have been employed with great success to harvest energy from various shock loading and/or vibration and oscillatory motions in numerous systems. In these systems, the external stimuli is used to store mechanical energy in the spring of a mass-spring unit which is attached to a piezoelectric element or a magnet and coil generator, and generate electrical energy as the vibrating mass-spring unit undergoes vibration and applies a cyclic load to the piezoelectric element. In this paper, the implementation of such energy harvesting power sources with a novel motion-doubling mechanism is presented. This novel force transmission method has two key advantages. Firstly, it provides the means to amplify the force applied to the piezoelectric element. Secondly, it provides the means of doubling the number of cycles of compressive forces applied to the piezoelectric elements during each cycle of vibration as compared to the direct mass-spring-piezoelectric generators that have been developed to date. The motion doubling and the resulting halving of the required number of cycles of vibration of the mass-spring unit for generating a certain amount of electrical energy has the effect of significantly increasing the mechanical to electrical energy conversion efficiency of the power source by significantly reducing structural damping losses in the spring element and by the increase in the level of force that is applied to the energy harvesting piezoelectric elements. The design and prototype fabrication of such an energy harvesting power sources is discussed.


Piezoelectric elements are commonly installed in shoe sole to make use of the piezoelectric effect due to the vibration generated by the human motion. Piezoelectric shoe is a great device that can be used to harvest energy and can be improved by adding more piezoelectric elements and providing storage to store the harvested energy. However, not many researchers focus on the analyzation of piezoelectric elements’ shape that may affect the efficiency of energy harvesting. In this paper, piezoelectric energy harvesting shoes are designed with piezoelectric elements installed inside the soles of the shoes, thereby gaining mechanical energy from user while walking and running. The mechanical energy was applied to the piezoelectric elements and converted into electrical energy. Bridge rectifier was used to convert the AC voltage output into DC voltage. The project focused on analyzation of the efficiency between round and square shaped piezoelectric elements. Different shape of the piezoelectric element produced different amount of output voltage. Square shaped piezoelectric tended to produce lesser output voltage than the round piezoelectric element. A round piezoelectric with diameter of 4.5cm produced mean output voltage up to 11.56V and square piezoelectric with size of 4.5cm x 4.5cm produced 6.12V. However, this all depended on how much pressure that was applied onto the piezoelectric elements.


Author(s):  
Charles J. Cross ◽  
Sanford Fleeter

The application of shunted piezoelectric elements to provide passive structural damping is investigated by means of experiments performed in the Purdue High Speed Axial Compressor Research Facility. Piezoelectric elements are bonded to three airfoils in the stator row. This airfoil is excited by the wakes generated by an upstream rotor. As the wakes drive the airfoil vibrations, the piezoelectrics experience a strain and in response produce an electric field. Tuned electrical circuits connected to the piezoelectrics as shunts dissipate this electrical energy, with multiple shunting techniques utilized. This electrical energy dissipation and the corresponding reduction in the airfoil mechanical energy result in a reduction in the magnitude of the resonant vibrations. Thus, these passive vibration control experiments demonstrate that shunted piezoelectrics have significant damping capability and could be practical for the elimination or minimization of gas turbine blading flow induced vibrations.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 729-736
Author(s):  
Jincheng He ◽  
Xing Tan ◽  
Wang Tao ◽  
Xinhai Wu ◽  
Huan He ◽  
...  

It is known that piezoelectric material shunted with external circuits can convert mechanical energy to electrical energy, which is so called piezoelectric shunt damping technology. In this paper, a piezoelectric stacks ring (PSR) is designed for vibration control of beams and rotor systems. A relative simple electromechanical model of an Euler Bernoulli beam supported by two piezoelectric stacks shunted with resonant RL circuits is established. The equation of motion of such simplified system has been derived using Hamilton’s principle. A more realistic FEA model is developed. The numerical analysis is carried out using COMSOL® and the simulation results show a significant reduction of vibration amplitude at the specific natural frequencies. Using finite element method, the influence of circuit parameters on lateral vibration control is discussed. A preliminary experiment of a prototype PSR verifies the PSR’s vibration reduction effect.


2018 ◽  
Vol 7 (2-1) ◽  
pp. 433
Author(s):  
K. Sri Vamsi Krishna ◽  
Shiva Prasad ◽  
R. Sabari Vihar ◽  
K. Babitha ◽  
K Veeranjaneyulu ◽  
...  

The main objective of this study is to increase the aerodynamic efficiency of turbine mounted novel wing. The main motive behind this work is to reduce the drag by attaining the positive velocity gradient and generate power by converting the stagnation pressure which also acts as emergency power source. By using the energy source of free stream air, Mechanical energy is converted into electrical energy. The obtained power is presented in terms of voltage generated at various angles of attack with different Reynolds number. Experimental analysis is carried out for NACA4415 airfoil at various angles with respect to free stream ranging from 0deg to 30deg from laminar to turbulent Reynolds number. The results were obtained using the research tunnel at IARE aerodynamic facility center. The aerodynamic advantage of this design in terms of voltage is 9.5 V at 35m/s which can be utilized for the aircraft on board power systems.


2019 ◽  
Vol 17 (1) ◽  
pp. 95
Author(s):  
Jumadi Tangko ◽  
Remigius Tandioga ◽  
Ismail Djufri ◽  
Riza Haardiyanti

Flywheel is a rotating mechanical device, which is generally used on four-wheeled vehicles. Flywheel has a moment of inertia that is able to withstand changes in rotational speed. The energy in flywheel is mechanical energy. This mechanical energy will be converted by generators into electrical energy. At the flywheel-based power plant, tests are carried out in the form of rotation, the generator power of the generator under no load or load conditions, and the time needed for this generator to survive. The results showed that the ability of the flywheel-based power plant in the condition without a backup supply to the motor in the condition of a generator without a load is able to generate power of 860.1 W for 22 seconds, while in a load-bearing generator capable of generating electricity by 708.75 W for 18 seconds 


2021 ◽  
Vol 34 (2) ◽  
pp. 157-172
Author(s):  
Deepak Anand ◽  
Singh Sambyal ◽  
Rakesh Vaid

The demand for energy is increasing tremendously with modernization of the technology and requires new sources of renewable energy. The triboelectric nanogenerators (TENG) are capable of harvesting ambient energy and converting it into electricity with the process of triboelectrification and electrostatic-induction. TENG can convert mechanical energy available in the form of vibrations, rotation, wind and human motions etc., into electrical energy there by developing a great scope for scavenging large scale energy. In this review paper, we have discussed various modes of operation of TENG along with the various factors contributing towards its efficiency and applications in wearable electronics.


2019 ◽  
Vol 4 (2) ◽  
pp. 50-55
Author(s):  
Syarif Moh Rofiq Al- Ghony ◽  
Subuh Isnur Haryudo ◽  
Jati Widyo Leksono

The electric motor is a device that serves to transform electrical energy into mechanical energy of motion. In this case the designed control system motor 3 phase by Smartphones through bluetooth network to find out the effective range of extremity. The methods used in the form of data capture of measurement effective range the furthest that can be reached by bluetooth to activate relay SPDT and motor 3 phase. Results of testing the most effective distance of the otomasisasi control system of motor 3 phase maximum as far as 15 meters with a time of pause 0.5 seconds.


2021 ◽  
Vol 2021 (6) ◽  
pp. 5360-5365
Author(s):  
TOMAS BLEJCHAR ◽  
◽  
SYLVA DRABKOVA ◽  
VACLAV JANUS ◽  
◽  
...  

The energy efficiency of systems, equipment, and sensors is nowadays intensively studied. The new generation of microelectronic sensors is very sophisticated and the energy consumption is in the microwatts range. The energy to power the microelectronic devices can be harvested from oscillating flow in small size channels and so replaceable batteries could be eliminated. Piezoelectric elements can convert energy from oscillation to electrical energy. This paper focuses on the simulation of periodic flow in the fluidic oscillator. CFD simulations were performed for several values of the flow rate. Experimental measurement was carried out under the same conditions as the CFD experiment. The main monitored and evaluated parameters were volume flow rate and pressure loss. Fluid oscillations were analysed based on CFD simulations and the theoretical maximum energy available for the deformation of piezoelectric elements and transformable into electrical energy was evaluated.


Sign in / Sign up

Export Citation Format

Share Document