scholarly journals A Nonresonant Hybridized Electromagnetic-Triboelectric Nanogenerator for Irregular and Ultralow Frequency Blue Energy Harvesting

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Weibo Xie ◽  
Lingxiao Gao ◽  
Lingke Wu ◽  
Xin Chen ◽  
Fayang Wang ◽  
...  
Keyword(s):  
Large Scale ◽  
Double Helix ◽  
Low Frequency ◽  
Triboelectric Nanogenerator ◽  
Frequency Wave ◽  
Ultralow Frequency ◽  
Jialing River ◽  
Working Principle ◽  
Double Helix Structure ◽  
Power Point

As a promising renewable energy source, it is a challenging task to obtain blue energy, which is irregular and has an ultralow frequency, due to the limitation of technology. Herein, a nonresonant hybridized electromagnetic-triboelectric nanogenerator was presented to efficiently obtain the ultralow frequency energy. The instrument adopted the flexible pendulum structure with a precise design and combined the working principle of electromagnetism and triboelectricity to realize the all-directional vibration energy acquisition successfully. The results confirmed that the triboelectric nanogenerator (TENG) had the potential to deliver the maximum power point of about 470 μW while the electromagnetic nanogenerator (EMG) can provide 523 mW at most. The conversion efficiency of energy of the system reached 48.48%, which exhibited a remarkable improvement by about 2.96 times, due to the elastic buffering effect of the TENG with the double helix structure. Furthermore, its ability to collect low frequency wave energy was successfully proven by a buoy in Jialing River. This woke provides an effective candidate to harvest irregular and ultralow frequency blue energy on a large scale.

scholarly journals The Connection between Coherent Structures and Low-Frequency Wave Packets in Large-Scale Atmospheric Flow

2004 ◽  
Vol 61 (21) ◽  
pp. 2616-2626 ◽  
Author(s):  
Daniel Hodyss ◽  
Terrence R. Nathan
Keyword(s):  
Coherent Structures ◽  
Large Scale ◽  
Wave Packets ◽  
Low Frequency ◽  
Wave Groups ◽  
Atmospheric Flow ◽  
Subsequent Formation ◽  
Frequency Wave ◽  
Wave Focusing ◽  
Group Velocities

Abstract A theory is presented that addresses the connection between low-frequency wave packets (LFWPs) and the formation and decay of coherent structures (CSs) in large-scale atmospheric flow. Using a weakly nonlinear evolution equation as well as the nonlinear barotropic vorticity equation, the coalescence of LFWPs into CSs is shown to require packet configurations for which there is a convergent group velocity field. These LFWP configurations, which are consistent with observations, have shorter wave groups with faster group velocities upstream of longer wave groups with slower group velocities. These wave group configurations are explained by carrying out a kinematic analysis of wave focusing, whereby a collection of wave groups focus at some point in space and time to form a large amplitude wave packet having a single wave front. The wave focusing and the subsequent formation of CSs are enhanced by zonal variations in the background flow, while nonlinearity extends the lifetimes of the CSs. These results are discussed in light of observed blocking formation in the Atlantic–European and South Pacific regions.

scholarly journals Triggered Convection, Gravity Waves, and the MJO: A Shallow-Water Model

2013 ◽  
Vol 70 (8) ◽  
pp. 2476-2486 ◽  
Author(s):  
Da Yang ◽  
Andrew P. Ingersoll
Keyword(s):  
Shallow Water ◽  
Large Scale ◽  
Low Frequency ◽  
Propagation Speed ◽  
Water Model ◽  
Shallow Water Model ◽  
Horizontal Scale ◽  
Frequency Wave ◽  
Large Scale Structures ◽  
Scale Structures

Abstract The Madden–Julian oscillation (MJO) is the dominant mode of intraseasonal variability in the tropics. Despite its primary importance, a generally accepted theory that accounts for fundamental features of the MJO, including its propagation speed, planetary horizontal scale, multiscale features, and quadrupole structures, remains elusive. In this study, the authors use a shallow-water model to simulate the MJO. In this model, convection is parameterized as a short-duration localized mass source and is triggered when the layer thickness falls below a critical value. Radiation is parameterized as a steady uniform mass sink. The following MJO-like signals are observed in the simulations: 1) slow eastward-propagating large-scale disturbances, which show up as low-frequency, low-wavenumber features with eastward propagation in the spectral domain, 2) multiscale structures in the time–longitude (Hovmöller) domain, and 3) quadrupole vortex structures in the longitude–latitude (map view) domain. The authors propose that the simulated MJO signal is an interference pattern of westward and eastward inertia–gravity (WIG and EIG) waves. Its propagation speed is half of the speed difference between the WIG and EIG waves. The horizontal scale of its large-scale envelope is determined by the bandwidth of the excited waves, and the bandwidth is controlled by the number density of convection events. In this model, convection events trigger other convection events, thereby aggregating into large-scale structures, but there is no feedback of the large-scale structures onto the convection events. The results suggest that the MJO is not so much a low-frequency wave, in which convection acts as a quasi-equilibrium adjustment, but is more a pattern of high-frequency waves that interact directly with the convection.

Propagation of Alfvén waves in ion-sound turbulent plasma

1971 ◽  
Vol 6 (2) ◽  
pp. 309-323 ◽  
Author(s):  
André Rogister
Keyword(s):  
Large Scale ◽  
Low Frequency ◽  
Alfven Waves ◽  
Turbulent Plasma ◽  
Larmor Radius ◽  
Alfvén Waves ◽  
Sound Waves ◽  
Very High Frequency ◽  
Frequency Wave ◽  
Finite Larmor Radius

The propagation of low-frequency, large-scale (compared to the ion Larmor frequency Ωi and radius Ri), oblique Alfvén waves in a turbulent plasma is investigated in the framework of kinetic theory. The turbulent field is the statistical average of one-dimensional ion-sound waves of very high frequency and short wavelength (ω ≫ ΩiRe≫ λ). In the absence of resonant particle effects, and to first order in a finite Larmor radius expansion, it is shown that the turbulence can lead either to spatial diffusion (damping) or anti-diffusion (growth), with Bohm scaling, of the low frequency wave. Finite Larmor radius and frequency effects in the propagation of oblique Alfvén waves are simultaneously obtained for arbitrary β plasma; the results can easily be generalized, merely by deforming certain integration contours, to obtain the corresponding Landau decrement.

scholarly journals Investigation of High-Frequency Internal Wave Interactions with an Enveloped Inertia Wave

2012 ◽  
Vol 2012 ◽  
pp. 1-12
Author(s):  
B. Casaday ◽  
J. Crockett
Keyword(s):  
Internal Wave ◽  
High Frequency ◽  
Wave Breaking ◽  
Large Scale ◽  
Critical Level ◽  
Low Frequency ◽  
Small Scale ◽  
Wave Interactions ◽  
Frequency Wave ◽  
Action Density

Using ray theory, we explore the effect an envelope function has on high-frequency, small-scale internal wave propagation through a low-frequency, large-scale inertia wave. Two principal interactions, internal waves propagating through an infinite inertia wavetrain and through an enveloped inertia wave, are investigated. For the first interaction, the total frequency of the high-frequency wave is conserved but is not for the latter. This deviance is measured and results of waves propagating in the same direction show the interaction with an inertia wave envelope results in a higher probability of reaching that Jones' critical level and a reduced probability of turning points, which is a better approximation of outcomes experienced by expected real atmospheric interactions. In addition, an increase in wave action density and wave steepness is observed, relative to an interaction with an infinite wavetrain, possibly leading to enhanced wave breaking.

scholarly journals ANTIREFLECTIVE VERTICAL STRUCTURE EXTENDED FOR ATTENUATION OF LOW FREQUENCY WAVES

2012 ◽  
Vol 1 (33) ◽  
pp. 49
Author(s):  
Jose Alberto Gonzalez-Escriva ◽  
Josep Ramon MEDINA
Keyword(s):  
Large Scale ◽  
Vertical Structure ◽  
Wave Reflection ◽  
Wind Waves ◽  
Low Frequency ◽  
Scale Model ◽  
Frequency Wave ◽  
Large Scale Model ◽  
Multiple Unit ◽  
Low Frequency Waves

A new maritime vertical structure was designed to improve the antireflective performance for wave reflection of wind waves and oscillations associated with intense storms, resonance waves in port basins, etc. Multiple unit chambers formed with long cell circuits (Medina et al., 2010) are responsible for the low frequency wave absorption that was studied through large-scale model testing.

scholarly journals Coaxial double helix structured fiber-based triboelectric nanogenerator for effectively harvesting mechanical energy

2020 ◽  
Vol 2 (10) ◽  
pp. 4482-4490
Author(s):  
Jinmei Liu ◽  
Nuanyang Cui ◽  
Tao Du ◽  
Gaoda Li ◽  
Shuhai Liu ◽  
...  
Keyword(s):  
Double Helix ◽  
Mechanical Energy ◽  
Triboelectric Nanogenerator ◽  
Helix Structure ◽  
Double Helix Structure

A new fiber-based triboelectric nanogenerator with a coaxial double helix structure is developed to effectively and long-timely harvest mechanical energy.

Effects of Low-Frequency Wave Interactions on Intraseasonal Oscillations

2004 ◽  
Vol 61 (24) ◽  
pp. 3025-3040 ◽  
Author(s):  
Paul E. Roundy ◽  
William M. Frank
Keyword(s):  
Large Scale ◽  
Low Frequency ◽  
Austral Summer ◽  
Multiple Linear Regression Model ◽  
High Amplitude ◽  
Wave Interactions ◽  
Frequency Wave ◽  
Intraseasonal Oscillations ◽  
The Tropics

Abstract Intraseasonal oscillations (ISOs) control much of the large-scale variability of convection in the Tropics on time scales of about 15–100 days. These disturbances are often thought to be dominated by eastward-propagating modes, especially during austral summer, but disturbances that propagate westward are also important. This work demonstrates by means of a multiple linear regression model and a brief case study that eastward- and westward-moving intraseasonal modes often cooperatively interact with one another to produce many of the characteristics of the observed Southern Hemisphere summer ISO. These interactions appear to be facilitated by topography and/or by the convective anomalies that are cooperatively induced by the eastward- and the westward-moving components of the oscillations. These interactions do not occur during every period of intraseasonal convective activity, but they do commonly occur during periods of high-amplitude convective anomalies. This analysis shows that eastward- and westward-moving intraseasonal modes should not be generally assumed to be linearly independent entities.

PROTOTIPE APLIKASI PENYIRAMAN TANAMAN MENGGUNAKAN SENSOR KELEMBABAN TANAH BERBASIS MICRO CONTOLLER ATMEGA 328

2019 ◽  
Vol 5 (1) ◽  
pp. 97-106
Author(s):  
Rudi Budi Agung ◽  
Muhammad Nur ◽  
Didi Sukayadi
Keyword(s):  
Soil Moisture ◽  
Growth And Development ◽  
Large Scale ◽  
Simple Method ◽  
Moisture Sensor ◽  
Sensor Development ◽  
Soil Moisture Sensor ◽  
Application Systems ◽  
Harvesting Systems ◽  
Working Principle

The Indonesian country which is famous for its tropical climate has now experienced a shift in two seasons (dry season and rainy season). This has an impact on cropping and harvesting systems among farmers. In large scale this is very influential considering that farmers in Indonesia are stilldependent on rainfall which results in soil moisture. Some types of plants that are very dependent on soil moisture will greatly require rainfall or water for growth and development. Through this research, researchers tried to make a prototype application for watering plants using ATMEGA328 microcontroller based soil moisture sensor. Development of application systems using the prototype method as a simple method which is the first step and can be developed again for large scale. The working principle of this prototype is simply that when soil moisture reaches a certainthreshold (above 56%) then the system will work by activating the watering system, if it is below 56% the system does not work or in other words soil moisture is considered sufficient for certain plant needs.

DNA Inspirited Rational Construction of Nonconventional Luminophores with Efficient and Color-Tunable Afterglow

2020 ◽  
Author(s):  
Yunzhong Wang ◽  
Saixing Tang ◽  
Yating Wen ◽  
Shuyuan Zheng ◽  
Bing Yang ◽  
...  
Keyword(s):  
Rational Design ◽  
Room Temperature ◽  
Double Helix ◽  
Mechanical Grinding ◽  
Room Temperature Phosphorescence ◽  
Color Tunable ◽  
Potential Applications ◽  
Rational Construction ◽  
Double Helix Structure ◽  
Made In

<div>Persistent room-temperature phosphorescence (p-RTP) from pure organics is attractive </div><div>due to its fundamental importance and potential applications in molecular imaging, </div><div>sensing, encryption, anticounterfeiting, etc.1-4 Recently, efforts have been also made in </div><div>obtaining color-tunable p-RTP in aromatic phosphors5 and nonconjugated polymers6,7. </div><div>The origin of color-tunable p-RTP and the rational design of such luminogens, </div><div>particularly those with explicit structure and molecular packing, remain challenging. </div><div>Noteworthily, nonconventional luminophores without significant conjugations generally </div><div>possess excitation-dependent photoluminescence (PL) because of the coexistence of </div><div>diverse clustered chromophores6,8, which strongly implicates the possibility to achieve </div><div>color-tunable p-RTP from their molecular crystals assisted by effective intermolecular </div><div>interactions. Here, inspirited by the highly stable double-helix structure and multiple </div><div>hydrogen bonds in DNA, we reported a series of nonconventional luminophores based on </div><div>hydantoin (HA), which demonstrate excitation-dependent PL and color-tunable p-RTP </div><div>from sky-blue to yellowish-green, accompanying unprecedentedly high PL and p-RTP </div><div>efficiencies of up to 87.5% and 21.8%, respectively. Meanwhile, the p-RTP emissions are </div><div>resistant to vigorous mechanical grinding, with lifetimes of up to 1.74 s. Such robust, </div><div>color-tunable and highly efficient p-RTP render the luminophores promising for varying </div><div>applications. These findings provide mechanism insights into the origin of color-tunable </div><div>p-RTP, and surely advance the exploitation of efficient nonconventional luminophores.</div>

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