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The Oscillation Dynamics of Droplets Subject to Electrowetting Actuation
摘要： The dynamic behavior of an Electrowetting-on-Dielectrics (EWOD) actuation process can be linked to certain fluid properties of the actuated polar liquid droplet. After actuation, inertia will lead to droplet oscillations where the contact angle asymptotically approaches the newly created surface tension equilibrium value. The decay behavior, frequency and amplitude of these oscillations can be related to material parameters such as density, viscosity and mass. In this work we study the characteristics of these oscillations, present simulation results and develop a measurement setup for first observations of oscillations on deionized water droplets. We show that there is a big difference between two grounding schemes, in particular regarding the dynamic movement of the liquid-gas interface. It turns out that only an electrical grounding from below leads to utilizable oscillations. Finally we point towards applications for future Lab-on-a-Chip applications.
关键词： actuator,FEM simulation,electrowetting,viscosity sensing,droplet oscillations,Lab-on-a-Chip
更新于2025-09-23 15:22:29
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Investigation into effect of coupled resonance phenomenon towards sensitivity enhancement of SAW conductivity sensors integrated with ZnO nanorods
摘要： In this work, FEM simulation was used to investigate the sensitivity of a one-port surface acoustic wave (SAW) resonator sensor to changes in electrical conductivity of the sensing medium composed of ZnO nanorods offering elastic loading on the surface of the resonator. A system of coupled resonators was formed when the height of the ZnO nanorods attached to the surface of the resonator was adjusted such that the resonant frequency of the nanorod approached the original resonant frequency of the SAW resonator. It was observed that the use of ZnO nanorods of resonant dimensions as sensing medium could enhance the sensitivity of the composite SAW sensor to changes in electrical conductivity of the sensing medium by up to 79 times. The comparatively higher sensitivity of the SAW conductivity sensor utilizing ZnO nanorods at resonant dimensions as sensing medium was attributed to the fact that the system of coupled resonators thus formed operates at a state of high sensitivity to changes induced in piezoelectric stiffening of the substrate during SAW propagation. The observations from FEM simulation conducted in the present work suggests strong prospects for the use of coupled resonance phenomenon at nanoscale for enhancing the sensitivity of conductivity-based SAW gas sensors and UV detectors employing 1-D ZnO nanostructures as sensing medium.
关键词： ZnO nanorods,sensitivity enhancement,SAW resonator,coupled resonance,FEM simulation
更新于2025-09-23 15:19:57
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AIP Conference Proceedings [AIP Publishing INTERNATIONAL SYMPOSIUM ON GREEN AND SUSTAINABLE TECHNOLOGY (ISGST2019) - Perak, Malaysia (23–26 April 2019)] INTERNATIONAL SYMPOSIUM ON GREEN AND SUSTAINABLE TECHNOLOGY (ISGST2019) - FEM simulation of deformations in strings of shingled solar cells subjected to mechanical reliability testing
摘要： Among several emerging interconnection technologies, shingled solar cell interconnection is the technology to realize highest power densities in solar modules. Its main feature is the replacement of ribbon stringing with direct interconnection by a slight overlapping of the solar cells using electrically conductive adhesives (ECA) as joint material. To succeed in a highly competitive market, this type of interconnection still has to prove its reliability, which requires a sound understanding of the loads this ECA joint faces during module lifetime. This study applies structural mechanic simulations based on the Finite Element Method (FEM) to investigate the impact of external loads according to IEC 61215 on a string of shingled solar cells within a solar module laminate. Linear elasticity is compared to the more realistic viscoelastic modelling of the encapsulant (EVA) and the ECA with the objective of reducing computational effort, which is caused by viscoelasticity. We found that linear elasticity can be applied in comparative studies to investigate the potential of different geometric designs to reduce mechanical stress in the joint. When it comes to the calculation of absolute values for stress and strain the strong viscoelastic properties of EVA and ECA cannot be neglected.
关键词： viscoelastic modelling,shingled solar cells,mechanical reliability testing,ECA joint,FEM simulation
更新于2025-09-12 10:27:22
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Distortion minimization of laser beam welded components by the use of finite element simulation and Artificial Intelligence
摘要： Welded components often require costly efforts to compensate for the thermally induced distortions. This is usually done by applying a specific pre-deformation or by reworking, for example by thermal straightening. These approaches are not practicable for joining complex structures. Therefore, a method that is capable of minimizing the distortions of a complex frame structure with multiple welds is presented. A meta-model by means of an Artificial Neural Network is used to predict the local distortions depending on the welding parameters within sub-areas. A genetic algorithm is utilized to efficiently find suitable welding parameters for the global structure. It could be shown that by applying the method, distortion minimized parameters from more than one billion potential parameter combinations are identified both efficiently and reliably.
关键词： Component distortions,Artificial Intelligence,Metamodeling,Genetic algorithms,FEM simulation,Artificial Neural Networks,Laser beam welding
更新于2025-09-12 10:27:22
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[IEEE 2018 3rd International Symposium on Instrumentation Systems, Circuits and Transducers (INSCIT) - Bento Gon?alves, Brazil (2018.8.27-2018.8.31)] 2018 3rd International Symposium on Instrumentation Systems, Circuits and Transducers (INSCIT) - Finite Element Modelling design and optimization of Love Wave mesoporous transducers for biochemical detection in liquid medium
摘要： We study numerically by a Finite Element Modeling (FEM) approach the design and the optimization of a Love wave transducer coated with a mesoporous sensitive layer. This association could allow to realize an easy functionalizable transducer for biochemical detection in liquid medium. The FEM approach is a good way to design the transducer by estimating many physical parameters in order to obtain a device which could work properly for a given application. Especially, by using a porous layer coated on an acoustic Love wave transducer, we need to be sure that the propagation parameters are still compatible with a usable device. In this paper, after a description of the reduced finite element model of the Love wave transducer, we show that the first experimental results are in a good agreement with the simulations. An “ultra-reduced” FEM approach of the Love wave transducer is carried out for easier consideration of the porous sensitive coating. Finally, experimental transducers are coated with TiO2 porous sensitive layers by the sol gel technique: the porosity is varied in the range from 10% to 25 %, the pore size from 10 nm to 200 nm, and the thickness from 100 nm to 500 nm. Simulated and experimental results are in good accordance, and allow us to conclude that such transducer could achieve a good propagation of the acoustic wave for biochemical sensing.
关键词： liquid medium,biochemical detection,SAW transducers,mesoporous layer,FEM simulation
更新于2025-09-11 14:15:04
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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - The Simulations of the Effect of the External Field in the Joule Balance
摘要： Due to the movement of the main magnet, the effect of the external field is a critical problem in the joule balance. The FEM simulations of the external field both in the electromagnet system and permanent magnet system are performed in this paper. The results show that although the error caused by the external field is much smaller in the permanent magnet system than that in the electromagnet system, it still needs to be further reduced. More efficient solutions should be considered to eliminate the effect of the external field when the permanent magnet system is used.
关键词： external field,FEM simulation,Kibble balance,joule balance,the Planck constant
更新于2025-09-10 09:29:36