scholarly journals Lightweight Unmanned Aerial System for Time-Domain Electromagnetic Prospecting—The Next Stage in Applied UAV-Geophysics

2021 ◽  
Vol 11 (5) ◽  
pp. 2060 ◽  
Author(s):  
Alexander Parshin ◽  
Ayur Bashkeev ◽  
Yuriy Davidenko ◽  
Marina Persova ◽  
Sergey Iakovlev ◽  
...  
Keyword(s):  
Time Domain ◽  
Gamma Ray ◽  
Pulse Generator ◽  
Measuring System ◽  
Electromagnetic Sounding ◽  
Mountainous Regions ◽  
Time Domain Electromagnetic ◽  
Unmanned System ◽  
Classical Triad ◽  
The Time Domain

Nowadays in solving geological problems, the technologies of UAV-geophysics, primarily magnetic and gamma surveys, are being increasingly used. However, for the formation of the classical triad of airborne geophysics methods in the UAV version, there was not enough technology for UAV-electromagnetic sounding, which would allow studying the geological environment at depths of tens and hundreds of meters with high detail. This article describes apparently the first technology of UAV-electromagnetic sounding in the time domain (TDEM, TEM), implemented as an unmanned system based on a light multi-rotor UAV. A measuring system with an inductive sensor—an analogue of a 20 × 20 or 50 × 50 m receiving loop is towed by a UAV, and a galvanically grounded power transmitter is on the ground and connected to a pulse generator. The survey is carried out along a network of parallel lines at low altitude with a terrain draping at a speed of 7–8 m/s, the maximum distance of the UAV’s departure from the transmitter line can reach several kilometers, thus the created technology is optimal for performing detailed areal electromagnetic soundings in areas of several square kilometers. The results of the use of the unmanned system (UAS) in real conditions of the mountainous regions of Eastern Siberia are presented. Based on the obtained data, the sensitivity of the system was simulated and it was shown that the developed technology allows one to collect informative data and create geophysical sections and maps of electrical resistivity in various geological situations. According to the authors, the emergence of UAV-TEM systems in the near future will significantly affect the practice of geophysical work, as it was earlier with UAV-magnetic prospecting and gamma-ray survey.

scholarly journals Megasource time-domain electromagnetic sounding at Poggi del Sasso - Cinigiano (GR)

1994 ◽  
Vol 37 (5 Sup.) ◽  
Author(s):  
G. V. Keller ◽  
P. Cantini ◽  
R. Carrara ◽  
O. Faggioni ◽  
E. Pinna
Keyword(s):  
Depth Profile ◽  
Time Domain ◽  
Environmental Conditions ◽  
Dipole Source ◽  
Electromagnetic Noise ◽  
Electromagnetic Sounding ◽  
Piecewise Constant ◽  
Time Domain Electromagnetic ◽  
The Time Domain ◽  
Single Set

An experiment was carried out in the vicinity of the “I Terzi” area in Southeastern Tuscany (fig. 1) to evaluate the applicability of the Time Domain Electromagnetic (TDEM) sounding method under the geological and environmental conditions prevailing in that area. An electromagnetic source was established using a motor-generator set and heavy cable. Measurements were attempted at four sites. Numerous samples of electromagnetic noise were recorded at each of these sites. At one site, signals transmitted for a grounded dipole source at 1.6 km distance were also recorded with the noise. The single set of observations has been processed and inverted to yield a six-layer piecewise constant resistivity depth-profile to a depth of about 2 km. The primary achievement of the experiment was demonstration of the praeticability of TDEM methods under the conditions prevailing in the site.

scholarly journals ROLE OF THE 3.6M DOT TO INVESTIGATE CONNECTIONS BETWEEN LONG-GRBS AND CORE-COLLAPSE SNE

2021 ◽  
Vol 53 ◽  
pp. 127-133
Author(s):  
A. Kumar ◽  
S. B. Pandey ◽  
R. Gupta ◽  
A. Aryan ◽  
A. J. Castro-Tirado ◽  
...  
Keyword(s):  
Time Domain ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Global Network ◽  
Core Collapse ◽  
Robotic Telescopes ◽  
The Time Domain ◽  
Time Critical ◽  
Near Future

Newly installed 3.6m DOT at Nainital (Uttarakhand) is a novel facility for the time domain astronomy. Because of the longitudinal advantage of India, it could be used to study new transients reported by a global network of robotic telescopes. Observations with the 4K × 4K CCD Imager at the axial port of the 3.6m DOT will be very helpful in the near future towards understanding the different physical aspects of time-critical events, e.g., Gamma-ray bursts (GRBs), Supernovae, Gravitational wave candidates, etc. Using the Imager with broadband filters (Bessel UBVRI and SDSS ugriz), ~6.5' × 6.5' images could be obtained to attempt various science goals in synergy with other multi-band facilities. In this study, we present an analysis of unpublished R-band data of GRB 171205A/SN 2017iuk spanning between ~12 to 105 days since burst, that observed using the 3.6m DOT with 4K × 4K CCD Imager. In the R-band light curve, a bump appears to start from ~3 days, which shows the peak at ~15 days after the burst, clearly indicates photometric evidence of association of SN with GRB 171205A.

scholarly journals Convergence of the uniaxial PML method for time-domain electromagnetic scattering problems

2021 ◽  
Author(s):  
Changkun Wei ◽  
Jiaqing Yang ◽  
Bo Zhang
Keyword(s):  
Time Domain ◽  
Electromagnetic Scattering ◽  
Scattering Problem ◽  
Three Dimensional ◽  
Scattering Problems ◽  
Laplace Transform Technique ◽  
The Laplace Transform ◽  
Time Domain Electromagnetic ◽  
Numer Anal ◽  
The Time Domain

In this paper, we propose and study the uniaxial perfectly matched layer (PML) method for three-dimensional time-domain electromagnetic scattering problems, which has a great advantage over the spherical one in dealing with problems involving anisotropic scatterers. The truncated uniaxial PML problem is proved to be well-posed and stable, based on the Laplace transform technique and the energy method. Moreover, the $L^2$-norm and $L^{\infty}$-norm error estimates in time are given between the solutions of the original scattering problem and the truncated PML problem, leading to the exponential convergence of the time-domain uniaxial PML method in terms of the thickness and absorbing parameters of the PML layer. The proof depends on the error analysis between the EtM operators for the original scattering problem and the truncated PML problem, which is different from our previous work (SIAM J. Numer. Anal. 58(3) (2020), 1918-1940).

Gamma-ray bursts: the time domain

1995 ◽  
Vol 231 (1-2) ◽  
pp. 95-102 ◽  
Author(s):  
Jay P. Norris
Keyword(s):  
Time Domain ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
The Time Domain

scholarly journals Characteristic Variability Time Scales of Long Gamma-Ray Bursts

2003 ◽  
Vol 214 ◽  
pp. 339-340
Author(s):  
Rongfeng Shen ◽  
Liming Song
Keyword(s):  
Power Density ◽  
Time Scales ◽  
Time Domain ◽  
Time Scale ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Time Dilation ◽  
Dilation Effect ◽  
The Time Domain ◽  
Intrinsic Characteristic

We determine the characteristic variability time scales for 410 bright long GRBs by locating the maximums of their Power Density Spectra (PDSs) defined and calculated in the time domain. The averaged characteristic variability time scale decreases with peak fluxe. This is consistent with the time dilation effect expected by cosmological origin of GRBs. The occurrence distribution of the characteristic variability time scale shows bimodality, which might be interpreted as that the long GRB sample is composed of two sub-classes with different intrinsic characteristic variability time scales.

Exploration of an alluvial aquifer in Oman by time-domain electromagnetic sounding

1998 ◽  
Vol 6 (3) ◽  
pp. 383-393 ◽  
Author(s):  
M. E. Young ◽  
R. G. M. de Bruijn ◽  
A. Salim Al-Ismaily
Keyword(s):  
Time Domain ◽  
Alluvial Aquifer ◽  
Electromagnetic Sounding ◽  
Time Domain Electromagnetic
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