Experimental investigations of Schumann resonance frequencies

1973 ◽  
Vol 35 (11) ◽  
pp. 2047-2053 ◽  
Author(s):  
K. Sao ◽  
M. Yamashita ◽  
S. Tanahashi ◽  
H. Jindoh ◽  
K. Ohta
Keyword(s):  
Experimental Investigations ◽  
Schumann Resonance ◽  
Resonance Frequencies

Optimization of spiral-shaped piezoelectric energy harvester using Taguchi method

2017 ◽  
Vol 24 (19) ◽  
pp. 4484-4491 ◽  
Author(s):  
R Tikani ◽  
L Torfenezhad ◽  
M Mousavi ◽  
S Ziaei-Rad
Keyword(s):  
Taguchi Method ◽  
Energy Harvester ◽  
Piezoelectric Materials ◽  
Mechanical Energy ◽  
Experimental Investigations ◽  
Optimum Level ◽  
Low Frequencies ◽  
Piezoelectric Energy ◽  
Resonance Frequencies ◽  
Design Values

Nowadays, environmental energy resources, especially mechanical vibrations, have attracted the attention of researchers to provide energy for low-power electronic circuits. A common method for environmental mechanical energy harvesting involves using piezoelectric materials. In this study, a spiral multimode piezoelectric energy harvester was designed and fabricated. To achieve wide bandwidth in low frequencies (below 15 Hz), the first three resonance frequencies of the beam were designed to be close to each other. To do this, the five lengths of the substrate layer were optimized by the Taguchi method, using an L27 orthogonal array. Each experiment of the Taguchi method was then simulated in ANSYS software. Next, the optimum level of each design variable was obtained. A test rig was then constructed based on the optimum design values and some experimental investigations were conducted. A good correlation was observed between measured and the finite element results.

scholarly journals Modifications of the middle atmosphere conductivity during sudden ionosphere disturbances and variations of schumann resonance frequencies

2018 ◽  
Vol 23 (1) ◽  
pp. 19-33
Author(s):  
I. Kudintseva ◽  
◽  
Y. Galyuk ◽  
A. Nikolaenko ◽  
M. Hayakawa ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Schumann Resonance ◽  
Resonance Frequencies

scholarly journals Investigation of Multifrequency Piezoelectric Energy Harvester

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Andrius Čeponis ◽  
Dalius Mažeika
Keyword(s):  
Frequency Response ◽  
Numerical Investigation ◽  
Energy Harvester ◽  
Wide Spectrum ◽  
The Body ◽  
Experimental Investigations ◽  
Response Characteristics ◽  
Piezoelectric Energy ◽  
Resonance Frequencies ◽  
Frequency Response Characteristics

This paper presents results of numerical and experimental investigations related to the piezoelectric energy harvester that operates at multifrequency mode. Employment of such operation principle provides an opportunity for obtaining frequency response characteristics of the harvester with several resonant frequencies and in this way increasing efficiency of the harvester at a wide spectrum of excitation frequencies. The proposed design of the energy harvester consists of five cantilevers which forms square type system. Cross sections of the cantilevers are modified by periodical cylindrical gaps in order to increase strain value and to obtain more uniform strain distribution along the cantilevers. Cantilevers are rigidly connected to each other and compose an indissoluble system. Square type harvester has seismic masses at every corner. These masses are placed under specific angle in order to reduce natural frequencies of the system and to create additional rotation moments in the body of harvester. Results of the numerical investigation revealed that harvester has five resonance frequencies in the range from 15 Hz to 300 Hz. Numerical analysis of the harvester revealed that the highest open circuit voltage density is 19.85 mV/mm3. Moreover, density of the total electrical energy reached 27.5 μJ/mm3. Experimental investigation confirmed that frequency response characteristics are obtained during numerical investigation and showed that energy density of the whole system reached 30.8 μJ/mm3.

Experimental Analysis of Continuous Vibrations in Dielectric Elastomer Membrane Actuators via Three-Dimensional Laser Vibrometry

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Sophie Nalbach ◽  
Gianluca Rizzello ◽  
Stefan Seelecke
Keyword(s):  
High Voltage ◽  
Membrane Surface ◽  
Three Dimensional ◽  
Dielectric Elastomer ◽  
Experimental Investigations ◽  
Laser Vibrometer ◽  
Vibration Modes ◽  
Resonance Frequencies ◽  
Out Of Plane ◽  
Voltage Signal

Dielectric elastomer (DE) membrane transducers are well known for exhibiting large deformations when subject to high voltage. Furthermore, DEs are characterized by an actuation bandwidth of several kilohertz, which allows their use in high-frequency applications, e.g., acoustic ones. The frequency response of DE membranes depends on many parameters such as geometry, pre-stress, and electrode pattern. By properly designing such parameters, it is possible to control vibration modes and resonance frequencies of the membrane, opening up a number of application scenarios. Motivated by this fact, this work presents the first experimental study of continuous vibrations generated in DE membranes via high-voltage excitation. The system under investigation consists of a squared DE membrane with a circular electrode, preloaded out of plane with a linear spring. Vibrations are generated by applying a broadband high-voltage signal to the DE membrane. A 3D laser vibrometer is used to reconstruct the three-dimensional oscillations of scanning points on the membrane surface. Experimental investigations are performed to study the effects of DE geometry and pre-stress on the membrane motion, in terms of resulting frequency spectrum and vibration modes.

MODIFICATIONS OF MESOSPHERIC CONDUCTIVITY IN SUDDEN IONOSPHERE DISTURBANCES AND CHANGES OF THE SCHUMANN RESONANCE FREQUENCIES

2018 ◽  
Vol 77 (8) ◽  
pp. 727-746
Author(s):  
I. G. Kudintseva ◽  
Yu. P. Galyuk ◽  
A. P. Nickolaenko ◽  
Masashi Hayakawa
Keyword(s):  
Schumann Resonance ◽  
Resonance Frequencies

scholarly journals Influence of Magnetic Field with Schumann Resonance Frequencies on Photosynthetic Light Reactions in Wheat and Pea

Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 149
Author(s):  
Vladimir Sukhov ◽  
Ekaterina Sukhova ◽  
Yulia Sinitsyna ◽  
Ekaterina Gromova ◽  
Natalia Mshenskaya ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Chronic Treatment ◽  
Quantum Yields ◽  
Photochemical Quenching ◽  
Schumann Resonance ◽  
Short Term ◽  
Resonance Frequencies ◽  
Non Photochemical Quenching

Photosynthesis is an important target of action of numerous environmental factors; in particular, stressors can strongly affect photosynthetic light reactions. Considering relations of photosynthetic light reactions to electron and proton transport, it can be supposed that extremely low frequency magnetic field (ELFMF) may influence these reactions; however, this problem has been weakly investigated. In this paper, we experimentally tested a hypothesis about the potential influence of ELFMF of 18 µT intensity with Schumann resonance frequencies (7.8, 14.3, and 20.8 Hz) on photosynthetic light reactions in wheat and pea seedlings. It was shown that ELFMF decreased non-photochemical quenching in wheat and weakly influenced quantum yield of photosystem II at short-term treatment; in contrast, the changes in potential and effective quantum yields of photosystem II were observed mainly under chronic action of ELFMF. It is interesting that both short-term and chronic treatment decreased the time periods for 50% activation of quantum yield and non-photochemical quenching under illumination. Influence of ELFMF on pea was not observed at both short-term and chronic treatment. Thus, we showed that ELFMF with Schumann resonance frequencies could influence photosynthetic light processes; however, this effect depends on plant species (wheat or pea) and type of treatment (short-term or chronic).

Experimental Investigations on Viscoelastic Properties of a Shape Memory Polymer

2014 ◽  
Author(s):  
Pauline Butaud ◽  
Morvan Ouisse ◽  
Vincent Placet ◽  
Emmanuel Foltête
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Viscoelastic Properties ◽  
Mechanical Characterization ◽  
Shape Memory Polymer ◽  
Viscoelastic Behavior ◽  
Experimental Investigations ◽  
Special Focus ◽  
Suitable Model ◽  
Resonance Frequencies

The shape memory polymers (SMPs) are polymeric smart materials which have the remarkable ability to recover their primary shape from a temporary one under an external stimulus. The study deals with the synthesis and the thermo-mechanical characterization of a thermally-actuated SMP, the tBA/PEGDMA, with a special focus on viscoelastic properties. The mechanical characterization is performed using three kinds of tests: quasi-static tensile tests, dynamic mechanical analysis (DMA) and modal tests. The first one allows the identification of the Youngs modulus and the Poisson’s ratio at ambient temperature. Modal analyses are done for various temperature values, and resonance frequencies are measured. In order to validate the time-temperature equivalence on this SMP, a DMA is performed under harmonic loading for different temperatures and a master curve highlights a complementarity of the results. Finally a suitable model for the viscoelastic behavior of the SMP is identified.

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