scholarly journals Active Cloaking and Illusion of Electric Potentials in Electrostatics

2021 ◽  
Author(s):  
Andreas Helfrich-Schkabarenko ◽  
Alik Ismail-Zadeh ◽  
Aron Sommer
Keyword(s):  
Electric Potential ◽  
Superposition Principle ◽  
Current Source ◽  
Three Dimensional ◽  
Numerical Results ◽  
Research Fields ◽  
Electric Potentials ◽  
Three Dimensional Models ◽  
First Time ◽  
A Current

Abstract Cloaking and illusion has been demonstrated theoretically and experimentally in several research fields. Here we present for the first time an active exterior cloaking device in electrostatics operating in a two-horizontally-layered electroconductive domain, and use the superposition principle to cloak electric potentials. The device uses an additional current source pattern introduced on the interface between two layers to cancel the total electric potential to be measured. Also, we present an active exterior illusion device allowing for detection of a signal pattern corresponding to any arbitrarily chosen current source instead of the existing current source. The performance of the cloaking/illusion devices is demonstrated by three-dimensional models and numerical experiments using synthetic measurements of the electric potential. Sensitivities of numerical results to a noise in measured data and to a size of cloaking devices are analysed. The numerical results show quite reasonable cloaking/illusion performance, which means that a current source can be hidden electrostatically. The developed active cloaking/illusion methodology can be used in subsurface geo-exploration studies, electrical engineering, live sciences, and elsewhere.

scholarly journals Active cloaking and illusion of electric potentials in electrostatics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andreas Helfrich-Schkabarenko ◽  
Alik Ismail-Zadeh ◽  
Aron Sommer
Keyword(s):  
Electric Potential ◽  
Superposition Principle ◽  
Current Source ◽  
Three Dimensional ◽  
Numerical Results ◽  
Research Fields ◽  
Electric Potentials ◽  
Three Dimensional Models ◽  
First Time ◽  
A Current

AbstractCloaking and illusion has been demonstrated theoretically and experimentally in several research fields. Here we present for the first time an active exterior cloaking device in electrostatics operating in a two-horizontally-layered electroconductive domain, and use the superposition principle to cloak electric potentials. The device uses an additional current source pattern introduced on the interface between two layers to cancel the total electric potential to be measured. Also, we present an active exterior illusion device allowing for detection of a signal pattern corresponding to any arbitrarily chosen current source instead of the existing current source. The performance of the cloaking/illusion devices is demonstrated by three-dimensional models and numerical experiments using synthetic measurements of the electric potential. Sensitivities of numerical results to a noise in measured data and to a size of cloaking devices are analysed. The numerical results show quite reasonable cloaking/illusion performance, which means that a current source can be hidden electrostatically. The developed active cloaking/illusion methodology can be used in subsurface geo-exploration studies, electrical engineering, live sciences, and elsewhere.

Morphology of the cephalothorax integument of Bryocamptus pygmaeus (Copepoda: Harpacticoida: Canthocamptidae), based on a new research method

2021 ◽  
Vol 30 (2) ◽  
pp. 320-330
Author(s):  
A.A. Novikov ◽  
E.B. Fefilova
Keyword(s):  
Three Dimensional ◽  
Komi Republic ◽  
Southeastern Part ◽  
The North ◽  
Udmurt Republic ◽  
The Republic ◽  
A New Technique ◽  
Three Dimensional Models ◽  
New Research ◽  
First Time

The number and location of sensilla and pores of the cephalothorax integument of the species Bryocamptus pygmaeus (G.O. Sars, 1863) (Copepoda, Canthocamptidae) were studied for the first time on the material from several European regions: the southeastern part of the Bolshezemelskaya tundra (Ne­nets Autonomous District), the north of the Komi Republic, the Republic of Karelia, and the central part of European Russia (Udmurt Republic). In the samples examined, two groups of populations differing in the characters of cephalothorax integument were recognised. These differences were found to correlate with the variability of the endopod of fourth pair of female legs, which bears four setae in specimens of the eastern form, while a specimen examined from Karelia has five setae. Pore maps are composed for both groups of morphotypes. A statistical analysis was carried out based on a new technique using three-dimensional models of the cephalothorax. As a result of this analysis, a high similarity between individuals of the eastern form and differences of the latter from the Karelian specimen were revealed.

scholarly journals Enhanced macroboring and depressed calcification drive net dissolution at high-CO 2 coral reefs

2016 ◽  
Vol 283 (1842) ◽  
pp. 20161742 ◽  
Author(s):  
Ian C. Enochs ◽  
Derek P. Manzello ◽  
Graham Kolodziej ◽  
Sam H. C. Noonan ◽  
Lauren Valentino ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Skeletal Structure ◽  
Global Ocean ◽  
Biological Processes ◽  
Micro Computed Tomography ◽  
Dead Coral ◽  
Intergovernmental Panel ◽  
Three Dimensional Models ◽  
First Time ◽  
High Carbon Dioxide

Ocean acidification (OA) impacts the physiology of diverse marine taxa; among them corals that create complex reef framework structures. Biological processes operating on coral reef frameworks remain largely unknown from naturally high-carbon-dioxide (CO 2 ) ecosystems. For the first time, we independently quantified the response of multiple functional groups instrumental in the construction and erosion of these frameworks (accretion, macroboring, microboring, and grazing) along natural OA gradients. We deployed blocks of dead coral skeleton for roughly 2 years at two reefs in Papua New Guinea, each experiencing volcanically enriched CO 2 , and employed high-resolution micro-computed tomography (micro-CT) to create three-dimensional models of changing skeletal structure. OA conditions were correlated with decreased calcification and increased macroboring, primarily by annelids, representing a group of bioeroders not previously known to respond to OA. Incubation of these blocks, using the alkalinity anomaly methodology, revealed a switch from net calcification to net dissolution at a pH of roughly 7.8, within Intergovernmental Panel on Climate Change's (IPCC) predictions for global ocean waters by the end of the century. Together these data represent the first comprehensive experimental study of bioerosion and calcification from a naturally high-CO 2 reef ecosystem, where the processes of accelerated erosion and depressed calcification have combined to alter the permanence of this essential framework habitat.

Current Source Design for 3D Magnetic Field Simulation

2013 ◽  
Vol 760-762 ◽  
pp. 1354-1359
Author(s):  
Zhi Li ◽  
Shu Bao Pan
Keyword(s):  
Magnetic Field ◽  
Design Principle ◽  
Current Source ◽  
Three Dimensional ◽  
Calibration Method ◽  
Constant Current ◽  
Constant Current Source ◽  
Precision Error ◽  
Magnetic Field Simulation ◽  
A Current

This paper designs a current source which is used for simulating the three dimensional magnetic field. Gives the circuit schematic, Analyzes the design principle of the circuit and puts forward the calibration method of software which is suitable for the operation in microprocessor and improves the output accuracy of the constant current source. Actual test shows that the output of the constant current source is 0.1mA-500mA and the precision error is less than 0.03% of full scale. It has been used in the degaussing device testing and maintenance. The performance is stable and reliable achieves good results.

Three‐dimensional model results for an electrical hole‐to‐surface method: Application to the interpretation of a field survey

Geophysics ◽  
1988 ◽  
Vol 53 (1) ◽  
pp. 85-103 ◽  
Author(s):  
D. Le Masne ◽  
C. Poirmeur
Keyword(s):  
Field Survey ◽  
Current Source ◽  
Electrical Potential ◽  
Three Dimensional ◽  
Electrical Parameters ◽  
Three Dimensional Model ◽  
Borehole Geophysics ◽  
Homogeneous Half Space ◽  
Surface Method ◽  
Three Dimensional Models

An important objective of borehole geophysics is to maximize information about inhomogeneities in the vicinity of existing boreholes. Three‐dimensional models (parallelepipedic inhomogeneities in a homogeneous half‐space) are used here to characterize the responses of an electrical hole‐to‐surface method ELECENT (ELECtrode ENTerrée) where conductive or resistive inhomogeneities (orebodies) occur in the vicinity of a borehole. Two types of surface measurements are carried out simultaneously at each station: electrical potential V (as in mise à la masse), and associated electrical field E. These two measured parameters give rise to three other parameters, two apparent resistivities (one for each V and E case) and another parameter quantifying the orientation of the E field. The influence of various geometrical and electrical parameters (such as the horizontal and vertical distances between the current source, the stations, and the inhomogeneity, and the size and resistivity of the inhomogeneity) on the five parameters above appears to be important. Values and positions of the extrema of these five parameters are characteristic of the geometrical and electrical parameters of the models. The orientation of the E field, for instance, is found to be critical to determining the shape of the inhomogeneity and its depth relative to the current source. The theoretical results obtained are used to interpret a field survey carried out around a borehole at the Beauvain prospect in France. Field maps of the five parameters show characteristics similar to the models described in the theoretical part of the study.

scholarly journals Application of the method of observing the natural impulse electromagnetic field of the Earth to trace watered faults on the example of Yeristovo quarry

2019 ◽  
Vol 109 ◽  
pp. 00128
Author(s):  
Kristina Zmiievska ◽  
Oleksandr Tubaltsev ◽  
Artur Zmiievskyi
Keyword(s):  
Electromagnetic Field ◽  
Reliable Method ◽  
Three Dimensional ◽  
Field Studies ◽  
Express Method ◽  
Tectonic Structure ◽  
The Earth ◽  
Three Dimensional Models ◽  
First Time ◽  
Natural Impulse

The article presents the results of applying the express method of observing the natural impulse electromagnetic field of the Earth to isolate flooded faults in areas adjacent to the Yeristovo quarry. The features of the geological and tectonic structure of the territory of the Yeristovo field are considered. According to the results of the field studies, for the first time, maps of the density of the natural impulse electromagnetic field of the Earth flux were constructed for this area, which made it possible to isolate and trace the positions of watering faults. In addition, to visualize the most difficult fragments of the structure of the plots, three-dimensional models were built. On the basis of the conducted research, it is possible to recommend the use of water catching wells using a reasonably economical and reliable method of observing the natural impulse electromagnetic field of the Earth. It is advisable to lay them in the zones of minimum values of the natural impulse electromagnetic field of the Earth, within the southern parts of the research sites. The use of advanced observations will avoid unproductive costs when drilling water-reducing wells.

On sensitivity of surface‐to‐borehole resistivity measurements to the attitude and the depth to center of a three‐dimensional spheroid

Geophysics ◽  
1985 ◽  
Vol 50 (7) ◽  
pp. 1173-1178 ◽  
Author(s):  
F. W. Yang ◽  
S. H. Ward
Keyword(s):  
Apparent Resistivity ◽  
Current Source ◽  
Three Dimensional ◽  
The Body ◽  
Simple Method ◽  
Pilot Studies ◽  
Resistivity Measurements ◽  
Oblate Body ◽  
A Current

Borehole‐to‐surface and surface‐to‐borehole resistivity measurements are versatile but not totally tested methods for detecting anomalies in the vicinity of a borehole. The former method has been discussed by several authors (Alfano, 1962; Merkel, 1971; Merkel and Alexander, 1971; Barnett, 1972; Snyder and Merkel, 1973; Snyder, 1976; Daniels, 1977, 1978, and 1983), but the latter has not received much attention. Morrison (1971) and Daniels (1977) are among the few who have addressed the problem. Each method has its own advantages. Surface‐to‐borehole resistivity measurements are made by placing a current source on the surface and measuring the apparent resistivity in a borehole in which the measuring electrodes are closer to the body than in the borehole‐to‐surface case. Pilot studies presented here suggest that the surface‐to‐borehole method can provide indicators of the attitude and the depth to the center of a body. This paper illustrates a simple method for qualitatively determining the attitude and the depth to the center of a body for a thin three‐dimensional (3-D) conductive oblate body with the surface‐to‐borehole technique. Attitude conveys the orientation of the body— horizontal, vertical dipping toward a borehole, or dipping away from a borehole.

Steady-state response of an elastic half-space to a moving dislocation of finite width

1983 ◽  
Vol 73 (1) ◽  
pp. 1-22
Author(s):  
J. Enrique Luco ◽  
John G. Anderson
Keyword(s):  
Half Space ◽  
Near Field ◽  
Three Dimensional ◽  
Elastic Half Space ◽  
Numerical Results ◽  
Finite Width ◽  
Slip Vector ◽  
State Response ◽  
Three Dimensional Models ◽  
Fault Length

abstract An analytical method to evaluate the transient response on the surface of an elastic half-space for a kinematic dislocation over an infinitely long fault of finite width and arbitrary dip is presented. The model includes finite rupture velocities in the direction of both the strike and dip of the fault. In this sense, it differs from previous two- and three-dimensional models which typically assume one of these velocities to be infinite. In addition to the effects of the free boundary, the model considers a slip vector in an arbitrary direction. The assumptions of infinite fault length and uniform rupture velocities account for the relative simplicity of the solution which is invariant to an observer moving along the strike of the fault with a speed equal to the rupture velocity. These assumptions limit the applicability of the solution to near-field locations far from the ends of realistic faults. A limited set of numerical results illustrating the types of pulse shapes obtained by use of this model, and, some tests to validate the derivation and the numerical results are presented.

scholarly journals Historic photographs of glaciers and glacial landforms from the R. S. Tarr collection at Cornell University

2019 ◽  
Author(s):  
Julie Elliott ◽  
Matthew E. Pritchard
Keyword(s):  
New York ◽  
Landscape Change ◽  
Three Dimensional ◽  
Gold Rush ◽  
Ecological Change ◽  
Cornell University ◽  
The Public ◽  
Three Dimensional Models ◽  
Glacial Landforms ◽  
First Time

Abstract. Historic photographs are useful for documenting glacier, environmental, and landscape change and we have digitized a collection of about 1949 images collected during an 1896 expedition to Greenland and trips to Alaska in 1905, 1906, 1909, and 1911, led by Ralph Stockman Tarr and his students at Cornell University. These images are openly available in the public domain through Cornell University Library (http://digital.library.cornell.edu/collections/tarr). The primary research targets of these expeditions were glaciers (there are about 990 photographs of at least 58 named glaciers) but there are also photographs of people, villages, geologic features, and formerly glaciated regions, including glacial features near Cornell University in Ithaca, New York. Some of the glaciers featured in the photographs have retreated significantly in the last century or even completely vanished. For many glaciers, multiple views are available, potentially allowing the use of photogrammetric techniques to generate three-dimensional models of the ice extent. While some of these photographs have been used in publications in the early 20th century, most of the images are only now widely available for the first time. The digitized collection also includes about 300 lantern slides made from the expedition photographs and other related images and used in classes and public presentations about glaciers and glaciations by several Cornell faculty over the decades. The images are of scientific interest for understanding glacier and ecological change, of public policy interest for documenting climate change, of historic and anthropological interest as local people, settlements, and gold-rush era paraphernalia are featured in the images, and of artistic and technological interest as the photographic techniques used were cutting-edge for their time.

Plastic replicas as three-dimensional models of pulps

1975 ◽  
Vol 39 (8) ◽  
pp. 544-546
Author(s):  
HL Wakkerman ◽  
GS The ◽  
AJ Spanauf
Keyword(s):  
Three Dimensional ◽  
Dimensional Models ◽  
Three Dimensional Models
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