On the Possibility of Using ULF/ELF Electromagnetic Waves from Undersea Cables to Detect Airplanes Submerged in the Ocean

2021 ◽  
Vol 36 (5) ◽  
pp. 486-495
Author(s):  
Dallin Smith ◽  
Jamesina Simpson
Keyword(s):  
Electromagnetic Waves ◽  
Sensor Array ◽  
Detection System ◽  
Three Dimensional ◽  
Low Frequency ◽  
Background Level ◽  
Ocean Water ◽  
Electromagnetic Signals ◽  
Undersea Cables ◽  
Difference Time

The loss of Malaysian Flight on March 8, 2014, and the subsequent lengthy search for the aircraft highlights the need for an effective detection system for locating airplanes that have crashed into the ocean. The goal of this paper is to test the feasibility of detecting submerged airplanes using ultra-low frequency and/or extremely-low frequency electromagnetic signals generated by undersea cables located along the bottom of the ocean. The proposed detection system is tested using three-dimensional finite-difference time-domain (FDTD) modeling of the cable source, ocean water, ground, and submerged object (aircraft). The perturbation caused by the object is obtained for different positions of the object relative to the cable source. The magnitude of the perturbation is compared to the expected background level for a depth of 3 km into the ocean. A sensor array is proposed for detecting objects within several km of the cable.

Comprehensive design analysis of a 3D printed sensor for readiness assessment applications

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tanushree Agarwal ◽  
Fatemeh Rahmani ◽  
Ishtique Zaman ◽  
Federico Gasbarri ◽  
Keivan Davami ◽  
...  
Keyword(s):  
Sensor Array ◽  
Short Circuit ◽  
Three Dimensional ◽  
Low Frequency ◽  
Optimal Placement ◽  
Chemical Plants ◽  
Readiness Assessment ◽  
Element Analysis ◽  
Content Type ◽  
Flexible Antenna

Purpose This paper aims to develop a comprehensive model of a magnetic sensor array that will be operational for a multitude of electric components in continuous and nonintrusive condition monitoring (CM) or in readiness assessment (RA) applications. Design/methodology/approach A universal nonintrusive model of a flexible antenna array is introduced to monitor and identify failures in electric machine drives. An adjustable sensor is designed to serve as a RA for a vast range of electrical elements in a typical power system by capturing the low-frequency radiated magnetic fields. Findings The optimal placement of the most sensitive radiated fields from several components has been discovered in this case study, enabling the detection of healthy current flow throughout. Thereafter, the short-circuit investigation, representing faulty situations, is implemented and compared with healthy cases. Practical implications This sensing technique can be used for nonintrusive CM of components that are out of reach and cannot have the sensor to be held around it such as components in offshore winds, wind energy generation and power and chemical plants. Originality/value The results are provided for three commonly used machines with a single sensor array with numerous settings. The three dimensional (3 D) finite element analysis is applied in the structuring of the sensor, detection of the optimum location and recognition of faults in the machines. Finally, based on the setup design, 3 D printing is used for the construction of the sensor array. Thus, the sensor array with fault detection avoids major component failures and increases system reliability/resiliency.

Simulation Analysis Based on Finite-Difference Time-Domain Algorithm for GIS Partial Discharge Detection

2013 ◽  
Vol 397-400 ◽  
pp. 2282-2286
Author(s):  
Qiu Ping Liu ◽  
Xu Hong Wang
Keyword(s):  
Time Domain ◽  
Electromagnetic Waves ◽  
Simulation Analysis ◽  
Detection System ◽  
Partial Discharge ◽  
Power Grids ◽  
Detection Technology ◽  
Global Power ◽  
Different Characteristics ◽  
Difference Time

Gas insulated switchgear (GIS) has been widely used in global power grids currently. However, there are several disadvantages of GIS which will cause partial discharge (PD) in the insulation and then make GIS shut down. In this paper, the application of the ultra high frequency (UHF)method for partial discharge monitoring is discussed in detail, including the placement of the UHF sensors , detection system and the different characteristics of the different defects in the PD signals diagram are analyzed as well. Finally, some relevant conclusions are drawn based on Finite-Diffrenee Time-Domain algorithm (FDTD) for simulation of the electromagnetic waves by UHF PD detection technology.

Comparison of ultra-low frequency electromagnetic signals with aftershock activity during the 1989 Loma Prieta earthquake sequence

1993 ◽  
Vol 83 (2) ◽  
pp. 347-357 ◽  
Author(s):  
M. A. Fenoglio ◽  
A. C. Fraser-Smith ◽  
G. C. Beroza ◽  
M. J. S. Johnston
Keyword(s):  
Failure Process ◽  
Low Frequency ◽  
Background Level ◽  
Magnetic Activity ◽  
Aftershock Activity ◽  
Loma Prieta Earthquake ◽  
Negative Results ◽  
Field Fluctuations ◽  
Loma Prieta ◽  
Electromagnetic Signals

Abstract Ultra-low frequency (0.01 to 10.0 Hz) magnetic field fluctuations near the epicenter of the 1989 Loma Prieta earthquake rose sharply immediately before the earthquake following indications of increased disturbance during the previous 12 days. The magnetic activity remained much higher than the pre-earthquake background level for 6 weeks following the mainshock. These observations suggest a causal relationship between the earthquake failure process and the magnetic signals. A search for similar precursory electromagnetic signals associated with aftershocks of this earthquake yields negative results. Specifically, no correlation appears to exist between the amplitude of the electromagnetic activity and the frequency or magnitude of aftershocks following the mainshock. Either a “threshold” earthquake magnitude larger, in this case, than ML 5.5, may be necessary to generate precursory electromagnetic signals or the continued generation of magnetic signals related to the mainshock may have masked signals generated by the larger aftershocks.

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 Reflections on iridescent neck and breast feathers of the peacock, Pavo cristatus

2018 ◽  
Vol 9 (1) ◽  
pp. 20180043 ◽  
Author(s):  
Pascal Freyer ◽  
Bodo D. Wilts ◽  
Doekele G. Stavenga
Keyword(s):  
Three Dimensional ◽  
Refractive Indices ◽  
Rectangular Lattice ◽  
Pavo Cristatus ◽  
Feather Coloration ◽  
Air Channels ◽  
Difference Time ◽  
Modelling Methods ◽  
Reflection Characteristics ◽  
Reflectance Measurements

The blue neck and breast feathers of the peacock are structurally coloured due to an intricate photonic crystal structure in the barbules consisting of a two-dimensionally ordered rectangular lattice of melanosomes (melanin rodlets) and air channels embedded in a keratin matrix. We here investigate the feather coloration by performing microspectrophotometry, imaging scatterometry and angle-dependent reflectance measurements. Using previously determined wavelength-dependent refractive indices of melanin and keratin, we interpret the spectral and spatial reflection characteristics by comparing the measured spectra to calculated spectra by effective-medium multilayer and full three-dimensional finite-difference time-domain modelling. Both modelling methods yield similar reflectance spectra indicating that simple multilayer modelling is adequate for a direct understanding of the brilliant coloration of peacock feathers.

scholarly journals Evolution of a narrow-band spectrum of random surface gravity waves

2003 ◽  
Vol 478 ◽  
pp. 1-10 ◽  
Author(s):  
KRISTIAN B. DYSTHE ◽  
KARSTEN TRULSEN ◽  
HARALD E. KROGSTAD ◽  
HERVÉ SOCQUET-JUGLARD
Keyword(s):  
Three Dimensional ◽  
Low Frequency ◽  
Three Dimensions ◽  
Band Spectrum ◽  
Nls Equation ◽  
Random Surface ◽  
Narrow Bandwidth ◽  
Quasi Stationary State ◽  
The Stability ◽  
Three Dimensional Simulations

Numerical simulations of the evolution of gravity wave spectra of fairly narrow bandwidth have been performed both for two and three dimensions. Simulations using the nonlinear Schrödinger (NLS) equation approximately verify the stability criteria of Alber (1978) in the two-dimensional but not in the three-dimensional case. Using a modified NLS equation (Trulsen et al. 2000) the spectra ‘relax’ towards a quasi-stationary state on a timescale (ε2ω0)−1. In this state the low-frequency face is steepened and the spectral peak is downshifted. The three-dimensional simulations show a power-law behaviour ω−4 on the high-frequency side of the (angularly integrated) spectrum.

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