Polarity reversal
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ON POLAR MAGNETIC FIELD REVERSAL AND SURFACE FLUX TRANSPORT DURING SOLAR CYCLE 24 Open
As each solar cycle progresses, remnant magnetic flux from active regions\n(ARs) migrates poleward to cancel the old-cycle polar field. We describe this\npolarity reversal process during Cycle 24 using four years (2010.33--2014.33)\nof lin…
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Electrokinetic remediation of soil polluted with insoluble organics using biological permeable reactive barriers: Effect of periodic polarity reversal and voltage gradient Open
This study investigated the remediation of clay soil polluted with low-solubility organics (diesel hydrocarbons) using a combined electrochemical-biological technology. Electrokinetic soil flushing was used, coupled with a biological perme…
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Earth’s magnetic field is probably not reversing Open
Significance Earth’s magnetic field is generated in Earth’s convecting liquid iron outer core and protects Earth’s surface from harmful solar radiation. The field has varied on different timescales throughout geological history, and these …
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Synchronizing volcanic, sedimentary, and ice core records of Earth’s last magnetic polarity reversal Open
Earth’s last magnetic field reversal was complex, with excursions at 795 and 784 ka before a final polarity flip at 773 ka.
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Pulsed Electric Fields-Assisted Extraction of Valuable Compounds From Arthrospira Platensis: Effect of Pulse Polarity and Mild Heating Open
The present study aimed to investigate the effect of the main pulsed electric field (PEF) process parameters on the cell damages of A. platensis microalgae and the extractability of valuable compounds [water-soluble proteins (WSP), C-phyco…
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Effect of the polarity reversal frequency in the electrokinetic-biological remediation of oxyfluorfen polluted soil Open
This work studies the feasibility of the periodic polarity reversal strategy (PRS) in a combined electrokinetic-biological process for the remediation of clayey soil polluted with a herbicide. Five two-weeks duration electrobioremediation …
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Dynamics of surface charge and electric field distributions on basin‐type insulator in GIS/GIL due to voltage polarity reversal Open
In this study, a simulation model of surface charge accumulation has been established. The model considers three accumulation ways, i.e. electrical conduction within the gas, through insulator volume and along the insulator surface. The ge…
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Solar cycle 24: An unusual polar field reversal Open
Context. It is well known that the polarity of the Sun’s magnetic field reverses or flips around the maximum of each 11 year solar cycle. This is commonly known as polar field reversal and plays a key role in deciding the polar field stren…
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DC electrical tree growth in epoxy resin and the influence of the size of inceptive AC trees Open
Electrical tree propagation is a precursor to dielectric failure in high voltage polymeric insulation. Tree growth has been widely studied under AC conditions, but its behavior under DC is not well understood. The aim of this work was to e…
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Extensional Polarity Change in Continental Rifts: Inferences From 3‐D Numerical Modeling and Observations Open
Extensional basins often show along‐strike variability in terms of fault geometries, basement structures, subsidence, and thermal evolution. This is particularly pronounced when extension reactivates preexisting suture zones with opposing …
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Investigation of electrode passivation during electrocoagulation treatment with aluminum electrodes for high silica content produced water Open
One of the main challenges for the implementation of electrocoagulation (EC) in water treatment are fouling and passivation of the electrodes, especially for applications with high contaminant concentrations. For the first time, we investi…
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Lightning as a space‐weather hazard: UK thunderstorm activity modulated by the passage of the heliospheric current sheet Open
Lightning flash rates, R L , are modulated by corotating interaction regions (CIRs) and the polarity of the heliospheric magnetic field (HMF) in near‐Earth space. As the HMF polarity reverses at the heliospheric current sheet (HCS), typica…
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Analysis of Cable Overvoltages in Symmetrical Monopolar and Rigid Bipolar HVDC Configuration Open
The symmetrical monopolar configuration is the prevailing scheme configuration for high voltage direct current (HVDC) interconnectors utilizing themodular multilevel converter (MMC) topology. However, the rigid bipolar configuration is gai…
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Designing HVDC GIS/GIL spacer to suppress charge accumulation Open
To suppress the charge accumulation on the spacer surface in direct current (DC) gas insulated transmission line (GIL) is an important and emergent issue for the development of a clean, safe and economic smart grid. A design method of the …
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DC Model Cable under Polarity Inversion and Thermal Gradient: Build-Up of Design-Related Space Charge Open
In the field of energy transport, High-Voltage DC (HVDC) technologies are booming at present due to the more flexible power converter solutions along with needs to bring electrical energy from distributed production areas to consumption si…
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Multidecadally resolved polarity oscillations during a geomagnetic excursion Open
Significance A stalagmite-based paleomagnetic record of the post-Blake excursion reveals details of repeated centennial–millennial interhemispheric polarity drifts and saw-tooth inclination oscillations during periods of low geomagnetic fi…
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Partial discharge behavior under operational and anomalous conditions in HVDC systems Open
Power cables undergo various types of overstressing conditions during their operation that influence the integrity of their insulation systems. This causes accelerated ageing and might lead to their premature failure in severe cases. This …
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Electrical Tree Initiation and Growth in Silicone Rubber under Combined DC-Pulse Voltage Open
Electrical tree is a serious threat to silicone rubber (SIR) insulation and can even cause breakdown. Electrical trees under alternating current (AC) and direct current (DC) voltage have been widely researched. While there are pulses in hi…
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Effect of polarity reversal on the enhanced electrokinetic remediation of 2,4-D-polluted soils: A numerical study Open
This article presents a numerical study of the transport phenomena involved in the electrokinetic remediation of soils polluted with polar pesticides. 2,4-Dichlorophenoxyacetic acid is used as a representative of this pesticide type. A one…
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Relationship between pore size and reversible and irreversible immobilization of ionic liquid electrolytes in porous carbon under applied electric potential Open
Transport of electrolytes in nanoporous carbon-based electrodes largely defines the function and performance of energy storage devices. Using molecular dynamics simulation and quasielastic neutron scattering, we investigate the microscopic…
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Self-replicating subduction zone initiation by polarity reversal Open
Subduction zones have recurrently formed on Earth. Previous studies have, however, suggested that they are unlikely to start in the interior of a pristine ocean. Instead, they seem to be more likely to form from another pre-existing subduc…
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Soft-mode driven polarity reversal in ferroelectrics mapped by ultrafast x-ray diffraction Open
Quantum theory has linked microscopic currents and macroscopic polarizations of ferroelectrics, but the interplay of lattice excitations and charge dynamics on atomic length and time scales is an open problem. Upon phonon excitation in the…
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Circular Dichroism and Isotropy – Polarity Reversal of Ellipticity in Molecular Films of 1,1’‐Bi‐2‐Naphtol Open
We have studied the circular dichroism (CD), in the ultraviolet and visible regions, of the transparent, chiral molecule 1,1’‐Bi‐2‐naphtol (BINOL) in 1.5 μm thick films. The initial transparent film shows an additional negative cotton effe…
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Correction: Carbon dots with tunable dual emissions: from the mechanism to the specific imaging of endoplasmic reticulum polarity Open
Correction for ‘Carbon dots with tunable dual emissions: from the mechanism to the specific imaging of endoplasmic reticulum polarity’ by Shuang E et al., Nanoscale, 2020, 12, 6852–6860, DOI: 10.1039/C9NR10982J.
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Bromine radical as a visible-light-mediated polarity-reversal catalyst Open
Polarity-reversal catalysts enable otherwise sluggish or completely ineffective reactions which are characterized by unfavorable polar effects between radicals and substrates. We herein disclose that when irradiated by visible light, bromi…
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Space charge dynamics in epoxy resin under voltage polarity reversal at various temperatures Open
Epoxy resin has been used to cast the core of the dry‐type high voltage direct current bushings and can accumulate space charge under high electric fields at high temperatures, which is believed to be a potential threat to the safe operati…
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Cardiac Response to Low-Energy Field Pacing Challenges the Standard Theory of Defibrillation Open
Background— The electric response of myocardial tissue to periodic field stimuli has attracted significant attention as the basis for low-energy antifibrillation pacing, potentially more effective than traditional single high-energy shocks…
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Research on the dynamic characteristics of electric field distribution of the ± 1100 kV Ultra high voltage converter transformer valve‐side bushing using weakly ionised gas conductance model Open
Ultra high voltage (UHV) converter transformer valve‐side bushings are the key equipment indirect current (DC) transmission projects, and are subjected to high voltage and large current with large number of harmonics simultaneously. The el…
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Electrical Treeing in Cable Insulation under Different HVDC Operational Conditions Open
Electrical treeing (ET) can irreversibly deteriorate the insulation of polymeric power cables leading to a complete failure. This paper presents the results of an experimental investigation into the effects of unipolar and polarity reversi…
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Effect of Stimulus Polarity on Physiological Spread of Excitation in Cochlear Implants Open
Background: Contemporary cochlear implants (CIs) use cathodic-leading, symmetrical, biphasic current pulses, despite a growing body of evidence that suggests anodic-leading pulses may be more effective at stimulating the auditory system. H…