scholarly journals COMBINATION EFFECT OF PNEUMATIC BREAKWATER AND OTHER TYPE BREAKWATER ON WAVE DAMPING

1978 ◽  
Vol 1 (16) ◽  
pp. 131
Author(s):  
Yuichi Iwagaki ◽  
Toshiyuki Asano ◽  
Tsutomu Honda
Keyword(s):  
Low Frequency ◽  
Surface Flow ◽  
Transmission Factor ◽  
Combination Effect ◽  
Wave Damping ◽  
Submerged Breakwater ◽  
Damping Effect ◽  
Guide Plate ◽  
Floating Breakwater ◽  
Low Frequency Waves

This paper deals experimentally with combinations of the pneumatic breakwater and other type breakwaters in order to increase the effectiveness of wave damping. Firstly, a submerged breakwater is picked up, and the wave damping effect of this combined type breakwater is examined. Results obtained in this experiment show that some improvements on the wave damping are found for low frequency waves that cannot be damped by the pneumatic breakwater only. The reason of appearence of the combination effect is explained that a part of energy of the transmitted waves over the submerged breakwater transfers to shorter period waves. Secondly, a floating breakwater is combined with the pneumatic breakwater. Experiments show that the transmission factor for high frequency waves becomes smaller than that of the pneumatic breakwater only, while there is not so much wave damping effect for low frequency waves even when the floating breakwater is combined. In addition, a guide plate is set below the bottom of the floating breakwater in order to increase the horizontal flow velocity for a given air discharge. It is found that the velocity of horizontal surface flow by using the guide plate increases as much as about 1.3 times that in the case of the pneumatic breakwater only. As a result, a little improvement on the wave damping due to the guide plate is also found.

scholarly journals ON THE FLOATING BREAKWATER - A NEW ARRANGEMENT

1986 ◽  
Vol 1 (20) ◽  
pp. 148
Author(s):  
C.H. Lee ◽  
S.W. Twu
Keyword(s):  
Wave Damping ◽  
Model Studies ◽  
Damping Effect ◽  
Floating Breakwater ◽  
New Type ◽  
The One ◽  
Better Than

A new type of floating breakwater composed of net-tubes and buoy-balls is presented in this paper. A series of model studies have been carried out for several arrangements of this structure. As wave damping effect is concerned, a case that the structure being set vertically is shown to be better than the one being set horizontally, while more than two rows of the structures are set vertically and separately, a case which being connected with ropes between adjoining rows is proved to be better than the case without connecting ropes.

PEMANFAATAN RADIASI ENERGI TEGANGAN 150 KV UNTUK LAMPU LED PENERANGAN JALAN

Jurnal Teknik ◽  
2018 ◽  
Vol 7 (1) ◽  
Author(s):  
Mauludi Manfaluthy
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
High Voltage ◽  
Low Frequency ◽  
Energy Utilization ◽  
World Health ◽  
Electromagnetic Signals ◽  
Health Organization ◽  
The Magnetic Field ◽  
Low Frequency Waves

WHO (World Health Organization) concludes that not much effect is caused by electric field up to 20 kV / m in humans. WHO standard also mentions that humans will not be affected by the magnetic field under  100 micro tesla and that the electric field will affect the human body with a maximum standard of 5,000 volts per meter. In this study did not discuss about the effect of high voltage radiation SUTT (High Voltage Air Channel) with human health. The research will focus on energy utilization of SUTT radiation. The combination of electric field and magnetic field on SUTT (70-150KV) can generate electromagnetic (EM) and radiation waves, which are expected to be converted to turn on street lights around the location of high voltage areas or into other forms. The design of this prototype works like an antenna in general that captures electromagnetic signals and converts them into AC waves. With a capacitor that can store the potential energy of AC and Schottky diode waves created specifically for low frequency waves, make the current into one direction (DC). From the research results obtained the current generated from the radiation is very small even though the voltage is big enough.Keywords : Radiance Energy, Joule Thief, and  LED Module.

scholarly journals Integral Equations for Problems on Wave Propagation in Near-Earth Plasma

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1395
Author(s):  
Danila Kostarev ◽  
Dmitri Klimushkin ◽  
Pavel Mager
Keyword(s):  
Magnetic Field ◽  
Integral Equations ◽  
Field Potential ◽  
Low Frequency ◽  
Fredholm Equation ◽  
Compression Waves ◽  
Parallel Component ◽  
Electric Field Potential ◽  
The Magnetic Field ◽  
Low Frequency Waves

We consider the solutions of two integrodifferential equations in this work. These equations describe the ultra-low frequency waves in the dipol-like model of the magnetosphere in the gyrokinetic framework. The first one is reduced to the homogeneous, second kind Fredholm equation. This equation describes the structure of the parallel component of the magnetic field of drift-compression waves along the Earth’s magnetic field. The second equation is reduced to the inhomogeneous, second kind Fredholm equation. This equation describes the field-aligned structure of the parallel electric field potential of Alfvén waves. Both integral equations are solved numerically.

scholarly journals Electromagnetic power of lightning superbolts from Earth to space

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J.-F. Ripoll ◽  
T. Farges ◽  
D. M. Malaspina ◽  
G. S. Cunningham ◽  
E. H. Lay ◽  
...  
Keyword(s):  
Low Frequency ◽  
Optical Emission ◽  
High Energy ◽  
Very Low Frequency ◽  
Electromagnetic Power ◽  
Power Spectral ◽  
High Energy Tail ◽  
Van Allen Probes ◽  
Long Time ◽  
Low Frequency Waves

AbstractLightning superbolts are the most powerful and rare lightning events with intense optical emission, first identified from space. Superbolt events occurred in 2010-2018 could be localized by extracting the high energy tail of the lightning stroke signals measured by the very low frequency ground stations of the World-Wide Lightning Location Network. Here, we report electromagnetic observations of superbolts from space using Van Allen Probes satellite measurements, and ground measurements, and with two events measured both from ground and space. From burst-triggered measurements, we compute electric and magnetic power spectral density for very low frequency waves driven by superbolts, both on Earth and transmitted into space, demonstrating that superbolts transmit 10-1000 times more powerful very low frequency waves into space than typical strokes and revealing that their extreme nature is observed in space. We find several properties of superbolts that notably differ from most lightning flashes; a more symmetric first ground-wave peak due to a longer rise time, larger peak current, weaker decay of electromagnetic power density in space with distance, and a power mostly confined in the very low frequency range. Their signal is absent in space during day times and is received with a long-time delay on the Van Allen Probes. These results have implications for our understanding of lightning and superbolts, for ionosphere-magnetosphere wave transmission, wave propagation in space, and remote sensing of extreme events.

Preferential acceleration of heavy ions from thermal velocities

1968 ◽  
Vol 46 (10) ◽  
pp. S638-S641 ◽  
Author(s):  
D. B. Melrose
Keyword(s):  
Frequency Spectrum ◽  
High Frequency ◽  
Heavy Ions ◽  
Crab Nebula ◽  
Low Frequency ◽  
High Frequency Waves ◽  
Hydromagnetic Waves ◽  
The Crab Nebula ◽  
Low Frequency Waves

The acceleration of ions from thermal velocities is analyzed to determine conditions under which heavy ions can be preferentially accelerated. Two accelerating mechanisms involving high-and low-frequency hydromagnetic waves respectively are considered. Preferential acceleration of heavy ions occurs for high-frequency waves if the frequency spectrum falls off faster than (frequency)−1. For the low-frequency waves heavy ions are less effectively accelerated than lighter ions. However, very heavy ions can be preferentially accelerated, the abundances of the very heavy ions being enhanced by a factor Ai over the thermal abundances. Acceleration of ions in the envelope of the Crab nebula is considered as an example.

WIND observation of gyrating-like ion distributions and low frequency waves upstream from the Earth's bow shock

1997 ◽  
Vol 20 (4-5) ◽  
pp. 703-706 ◽  
Author(s):  
K. Meziane ◽  
C. Mazelle ◽  
C. d'Uston ◽  
H. Rème ◽  
R.P. Lin ◽  
...  
Keyword(s):  
Low Frequency ◽  
Bow Shock ◽  
Wind Observation ◽  
Ion Distributions ◽  
Earth’S Bow Shock ◽  
Low Frequency Waves
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