scholarly journals Array analysis of magnetic and electric field observatories in China: estimation of magnetotelluric impedances at very long periods

2020 ◽  
Vol 222 (1) ◽  
pp. 305-326
Author(s):  
Hui Wang ◽  
Gary Egbert ◽  
Yusong Yao ◽  
Jiulong Cheng
Keyword(s):  
Electric Field ◽  
Data Acquisition ◽  
Electric Fields ◽  
Principal Component ◽  
Array Analysis ◽  
Data Set ◽  
Wave Source ◽  
Long Period ◽  
Noise Characteristics ◽  
Almost All

SUMMARY Ten years (2008–2017) of continuous measurements from 40 electric and 36 magnetic sites collected in China for earthquake prediction research represent a unique EM array data set, which can be used to explore the challenging problem of very long-period MT data acquisition, to study source characteristics, and ultimately to learn about electric conductivity of Earth's mantle beneath East Asia. In this study, we focus on basic noise and signal characteristics in this data set, and on estimation of the MT impedances. We report a novel method to fix the numerous timing errors in the electric data caused by limitations in instrumentation and data acquisition. Then, we use multivariate array analysis to study signal and noise characteristics for periods from 250 s to 3.5 × 105 s (4 d). Signal-to-noise ratios (SNR) are above 30 dB in magnetic fields for the first two dominant modes, which correspond roughly to N–S and E–W quasi-uniform sources. SNRs for electric fields are lower, especially at very long periods, and especially for N–S electric components. There are clear peaks in signal strength at the daily variation (DV) periods, but source structure becomes more complex, and significant biases in MT impedance tensors are more often seen at these periods. The MT quasi-impedance, computed using the closest magnetic site for each electric site, is estimated by robust remote reference techniques (RR) and by using linear combinations of PCA (principal component analysis) modes that best approximate a uniform or plane-wave source (PW). For almost all sites, smooth impedances are obtained for periods up to 104 s using either approach. This result, and a more detailed analysis of impedances estimates obtained with shorter-wavelength (gradient) sources extracted from the array, suggests that source effects in MT impedances are minimal for periods below 104 s, at least at the latitude of China. At many sites curves can be extended a decade further, to 105 s, but here results are improved by carefully omitting DV bands and (at a few sites) with the PW approach. For longer periods (>105 s) SNR is very low in electric field channels at most sites, making estimation challenging. However, at a few sites, even some near big cities (e.g. including a site within 40 km of Beijing) smooth impedance components related to N–S magnetic sources (Zxx and Zyx) are obtained to periods to 3.5 × 105 s (4 d). This result suggests that cultural noise may not be the main impediment to collecting very long-period MT data.

scholarly journals Model for Deformation of Cells from External Electric Fields at or Near Resonant Frequencies

2020 ◽  
Author(s):  
L. Martinez ◽  
A. Dhruv ◽  
L. Lin ◽  
E. Balaras ◽  
M. Keidar
Keyword(s):  
Electric Field ◽  
Cancer Cells ◽  
Electric Fields ◽  
High Energy ◽  
Atmospheric Plasma ◽  
Maximum Effect ◽  
Viscoelastic Response ◽  
Resonant Frequencies ◽  
Wave Source ◽  
External Electric Fields

AbstractThis paper presents a numerical model to investigate the deformation of biological cells by applying external electric fields operating at or near cell resonant frequencies. Cells are represented as pseudo solids with high viscosity suspended in liquid media. The electric field source is an atmospheric plasma jet developed inhouse, for which the emitted energy distribution has been measured.Viscoelastic response is resolved in the entire cell structure by solving a deformation matrix assuming an isotropic material with a prescribed modulus of elasticity. To investigate cell deformation at resonant frequencies, one mode of natural cell oscillation is considered in which the cell membrane is made to radially move about its eigenfrequency. An electromagnetic wave source interacts with the cell and induces oscillation and viscoelastic response. The source carries energy in the form of a distribution function which couples a range of oscillating frequencies with electric field amplitude.Results show that cell response may be increased by the external electric field operating at or near resonance. In the elastic regime, response increases until a steady threshold value, and the structure moves as a damped oscillator. Generally, this response is a function of both frequency and magnitude of the source, with a maximum effect found at resonance. To understand the full effect of the source energy spectrum, the system is solved by considering five frequency-amplitude couplings. Results show that the total solution is a nonlinear combination of the individual solutions. Additionally, sources with different signal phases are simulated to determine the effect of initial conditions on the evolution of the system, and the result suggests that there may be multiple solutions within the same order of magnitude for elastic response and velocity. Cell rupture from electric stress may occur during application given a high energy source.SignificanceCold atmospheric plasma jets (CAPJs) have been widely researched for their potential applications in cancer therapy. Existing research has focused mainly on the ability of CAPJs to deliver a mixture of reactive species which can be absorbed by cancer cells and induce cell death. The objective of our study is to investigate the mechanical effect of CAPJ electromagnetic (EM) waves on interacting cells. By coupling the EM waves associated with plasma frequency and cell viscoelastic response, we have developed a numerical tool to investigate cell damage either by mechanical or thermal loads. This work is motivated by the promise of EM waves to function as a sensitizing agent for cancer cells in preparation for chemotherapy.

Molecular Electronics Including Temperature Effects Based on Dyes Pigments

2019 ◽  
Vol 19 (6) ◽  
pp. 3631-3636
Author(s):  
Adriana T Amador ◽  
Abel F. G Neto ◽  
Jorddy N Cruz ◽  
Fatima N. B Magno ◽  
Francisco C Marques ◽  
...  
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Molecular Electronics ◽  
Electric Fields ◽  
Density Functional ◽  
Functional Theory ◽  
Degradation Temperature ◽  
Red Color ◽  
The Density Functional Theory ◽  
Almost All

In this work we used the Density Functional Theory to study the thermodynamic properties from Brazilein (BZE) and Brazilin (BZI) molecules, main pigments responsible for the red color from Brazil wood. We did a comparison between the two dyes to then know which dye has better resistance to temperature (T ) and external electric field (E) values, aiming their potential to possible applications in solar cells, as excitons trainers. We have found that the BZE molecule becomes less stable after a temperature known as degradation temperature, and therefore enters oxidation state. However, BZE is more stable and more resistant to high temperatures. With respect to the applied external electric field, we find that BZE is more reactive to almost all the applied electric fields, thus more easily converted into energy in the form of electrical work.

scholarly journals Liposomes Under Real Cell Conditions Behave Like Real Cells with a Single Pulsed Electric Field

2019 ◽  
Author(s):  
Gen Urabe ◽  
Masaharu Shimada ◽  
Takumi Ogata ◽  
Sunao Katsuki
Keyword(s):  
Electric Field ◽  
Red Blood Cells ◽  
Physical Model ◽  
Electric Fields ◽  
Blood Cells ◽  
Pulsed Electric Fields ◽  
Molar Ratio ◽  
Real Cell ◽  
Almost All ◽  
Phosphate Buffered Saline

AbstractLiposomes are widely assumed to present a straightforward physical model of cells. However, almost all previous liposome experiments with pulsed electric fields (PEFs) have been conducted in low-conductivity liquids, a condition that differs significantly from that of cells in medium. Here, we prepared liposomes consisting of soy bean lecithin and cholesterol, at a molar ratio of 1:1, in higher-conductivity liquid that approximated the conditions of red blood cells in phosphate-buffered saline, with inner and outer liquid conductivities of 0.6 and 1.6 S/m, respectively. We found that a single 1.1 kV/cm, 400 μs PEF promoted cell-like spontaneous division of liposomes.

THE IMPROVEMENT OF THE HIGH VOLTAGE TESTING METHOD

2019 ◽  
pp. 4-14
Author(s):  
V. A. Syasko ◽  
S. S. Golubev ◽  
A. S. Musikhin
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Homogeneous Field ◽  
Inhomogeneous Field ◽  
Minimum Thickness ◽  
Air Gaps ◽  
Testing Method ◽  
Almost All

The high voltage spark testing method of protective dielectric coatings is applied in almost all manufacture areas and is governed by ISO, ASTM etc. However, all of it doesn’t pay proper attention to high voltage forming (DC or AC) and its polarity relative to electrode, influence of environment and electric field inhomogeneity. In that paper a detailed analysis of air gap breakdown forming processes was given. A dependence of electric field strength on an interelectrode gap length was given for homogeneous and highly inhomogeneous electric fields. It was shown a breakdown voltage of air gaps in highly inhomogeneous field is greatly less than in homogeneous field. Also, it is described the breakdown voltage of air gaps with positive polarity is less then with negative polarity. The possibility coatings testing with a minimum thickness up to 50 m while reducing the testing voltage without reducing the reliability of the results is shown.

scholarly journals Fatty Acids-Based Quality Index to Differentiate Worldwide Commercial Pistachio Cultivars

2018 ◽  
Author(s):  
Mahnaz Esteki ◽  
Parvin Ahmadi ◽  
Yvan Vander Heyden ◽  
Jesus Simal-Gandara
Keyword(s):  
Fatty Acid ◽  
Quality Index ◽  
Predictive Power ◽  
Principal Component ◽  
Chromatographic Fingerprint ◽  
Data Set ◽  
Linear Discriminant ◽  
Fatty Acid Data ◽  
Percent Accuracy ◽  
Almost All

The fatty-acid profiles of five main commercial pistachio cultivars, including Ahmad-Aghaei, Akbari, Chrok, Kalle-Ghouchi and Ohadi, were determined by gas chromatography: palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0), oleic (C18:1), linoleic (C18:2), linolenic (C18:3) arachidic (C20:0) and gondoic (C20:1) acid. Based on the oleic to linoleic acid (O/L) ratio, a quality index was determined for these five cultivars: Ohadi (2.40) < Ahmad-Aghaei (2.60) < Kale-Ghouchi (2.94) < Chrok (3.05) < Akbari (3.66). Principal component analysis (PCA) of the fatty-acid data yielded three significant PCs, which together account for 80.0% of the total variance in the data set. A linear discriminant analysis (LDA) model evaluated with cross validation correctly classified almost all samples: the average percent accuracy for the prediction set was 98.0%. The high predictive power for the prediction set shows the ability to indicate the cultivar of an unknown sample based on its fatty-acid chromatographic fingerprint.

3D marine magnetotelluric inversion: A hybrid impedance and direct-field approach

Geophysics ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. E335-E346
Author(s):  
Lutz Mütschard ◽  
Ketil Hokstad ◽  
Torgeir Wiik ◽  
Bjørn Ursin
Keyword(s):  
Electric Field ◽  
Real Data ◽  
Source Distribution ◽  
Impedance Tensor ◽  
Inversion Algorithm ◽  
Data Set ◽  
Wave Source ◽  
Field Approach ◽  
Impedance Inversion ◽  
Field Inversion

The measured electromagnetic field in magnetotellurics (MT) is composed of the natural source field and its subsurface response. Commonly, the data are represented as impedances, the complex ratio between the horizontal electric and magnetic fields. This measure is independent of the source distribution because the impedance-tensor estimation contains a deconvolution operator. We have used a Gauss-Newton-type 3D MT inversion scheme to compare impedance-data inversion with an inversion using the recorded electric field directly. The use of the observed electric field is beneficial to the inversion algorithm because it simplifies the estimation of the sensitivities. The direct-field approach permits the use of the observed data without processing, but it presumes knowledge of the source distribution. A method to estimate the time-variable strength and polarization of the incoming plane-wave source is presented and tested on synthetic and real-data examples. The direct-field inversion is successfully applied to a synthetic and a real data set within marine settings. A comparison with the conventional impedance inversion is conducted. The results of the synthetic data example are very similar, with a slightly more accurate reconstruction of the model in the impedance case, whereas the direct-field inversion produces a smoother inversion result when compared with the impedance case. The mapping of a resistive salt structure in the real-data example indicates deviations in the final conductivity models. The impedance inversion suggests a deeper rooted resistive structure, whereas the direct-field inversion predicts a more compact structure limited to the overburden. We have evaluated the advantages of the new approach like the simplification of the sensitivity calculation, limitations, and disadvantages like knowledge of the source distribution.

QUANTUM COHERENCE OF SUPERLATTICES IN TRIANGLE-WAVE ELECTRIC FIELDS

2000 ◽  
Vol 14 (01) ◽  
pp. 41-49 ◽  
Author(s):  
HAI-FENG LIU ◽  
XIAN-GENG ZHAO
Keyword(s):  
Electric Field ◽  
Exact Solutions ◽  
Electric Fields ◽  
Quantum Coherence ◽  
Mean Square Displacement ◽  
Initial Distribution ◽  
Coherent Motion ◽  
Mean Square ◽  
Long Period ◽  
The Mean

The problem of coherent motion of an electron in a long period superlattice driven by a triangle-wave electric field is studied. Exact solutions for the amplitude propagators, the field-induced polarization, the mean-square displacement, and the quasienergy spectrum of any initial distribution and long-range hopping coupling are obtained generally. Total collapse of the quasienergy spectrum is found to take place at certain field parameters, which leads to the transition between localization and delocalization. The transport property of the system is also investigated.

scholarly journals Effects of the airwave in time-domain marine controlled-source electromagnetics

Geophysics ◽  
2011 ◽  
Vol 76 (4) ◽  
pp. F251-F261 ◽  
Author(s):  
Jürg Hunziker ◽  
Evert Slob ◽  
Wim Mulder
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Time Domain ◽  
Beam Steering ◽  
Data Set ◽  
Controlled Source ◽  
Controlled Source Electromagnetics ◽  
Subsurface Reservoir ◽  
The Impact ◽  
Depth Water

In marine time-domain controlled-source electromagnetics (CSEM), there are two different acquisition methods: with horizontal sources for fast and simple data acquisition or with vertical sources for minimizing the effects of the airwave. Illustrations of the electric field as a function of space and time for various source antenna orientations, based on analytical formulation of the electric field in two half-spaces, provide insights into the properties of the airwave and the nature of diffuse electric fields. Observing the development of the electric field over time and space reveals that diffusive fields exhibit directionality. Therefore, techniques that have thus far mostly been applied to wavefields can be adapted for CSEM. Examples range from the well-known up-down decomposition to beam steering. Vertical sources have the advantage of not creating an airwave. On the other hand, it is quite difficult to achieve perfect verticality of the source antenna. Results, using a numerically modeled data set to analyze the impact of the airwave on a signal from a subsurface reservoir in the case of a slightly dipping vertical source, indicate that already for a dip of [Formula: see text], the airwave contributes 20% to the complete electric field in our configuration of reservoir depth, water thickness, and conductivity values.

scholarly journals Derivation of inner magnetospheric electric field (UNH-IMEF) model using Cluster data set

2008 ◽  
Vol 26 (9) ◽  
pp. 2887-2898 ◽  
Author(s):  
H. Matsui ◽  
P. A. Puhl-Quinn ◽  
V. K. Jordanova ◽  
Y. Khotyaintsev ◽  
P.-A. Lindqvist ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Electric Potential ◽  
Field Data ◽  
Input Parameter ◽  
Data Set ◽  
The Public ◽  
Cluster Data ◽  
Electric Field Increase ◽  
Low Altitude

Abstract. We derive an inner magnetospheric electric field (UNH-IMEF) model at L=2–10 using primarily Cluster electric field data for more than 5 years between February 2001 and October 2006. This electric field data set is divided into several ranges of the interplanetary electric field (IEF) values measured by ACE. As ring current simulations which require electric field as an input parameter are often performed at L=2–6.6, we have included statistical results from ground radars and low altitude satellites inside the perigee of Cluster in our data set (L~4). Electric potential patterns are derived from the average electric fields by solving an inverse problem. The electric potential pattern for small IEF values is probably affected by the ionospheric dynamo. The magnitudes of the electric field increase around the evening local time as IEF increases, presumably due to the sub-auroral polarization stream (SAPS). Another region with enhanced electric fields during large IEF periods is located around 9 MLT at L>8, which is possibly related to solar wind-magnetosphere coupling. Our potential patterns are consistent with those derived from self-consistent simulations. As the potential patterns can be interpolated/extrapolated to any discrete IEF value within measured ranges, we thus derive an empirical electric potential model. The performance of the model is evaluated by comparing the electric field derived from the model with original one measured by Cluster and mapped to the equator. The model is open to the public through our website.

Customer-Related Social Stressors

2015 ◽  
Vol 14 (4) ◽  
pp. 165-181 ◽  
Author(s):  
Sarah Dudenhöffer ◽  
Christian Dormann
Keyword(s):  
Service Providers ◽  
Principal Component ◽  
Well Being ◽  
Emotional Dissonance ◽  
Social Stressors ◽  
Data Set ◽  
Confirmatory Factor Analyses ◽  
Confirmatory Factor ◽  
Service Jobs ◽  
Single Data

Abstract. The purpose of this study was to replicate the dimensions of the customer-related social stressors (CSS) concept across service jobs, to investigate their consequences for service providers’ well-being, and to examine emotional dissonance as mediator. Data of 20 studies comprising of different service jobs (N = 4,199) were integrated into a single data set and meta-analyzed. Confirmatory factor analyses and explorative principal component analysis confirmed four CSS scales: disproportionate expectations, verbal aggression, ambiguous expectations, disliked customers. These CSS scales were associated with burnout and job satisfaction. Most of the effects were partially mediated by emotional dissonance. Further analyses revealed that differences among jobs exist with regard to the factor solution. However, associations between CSS and outcomes are mainly invariant across service jobs.

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