Polarity Time Research Articles

Breakdown Characteristics of Liquid Silicone Rubber in Needle-Plane Configuration Under Polarity Reversal

The results of breakdown voltages in liquid silicone rubber (LSiR) insulation under stepped polarity reversal voltages at a uniform temperature in a needle-plane electrode system are presented in this article. In the presence of defects such as sharp conductor projections or protrusions in the cable insulation stressed under polarity reversal direct current (dc) voltages, the electric field distribution is far more complex due to nonlinear insulation conductivity and time-dependent field distribution. The electric field distribution and space-charge accumulation are intricate functions of factors such as geometry and nonlinear conduction. In this article, a two-dimensional (2-D) axisymmetric model of a needle-plane geometry is developed using the finite-element method to compute the time-dependent field, space charge, and current density distribution under polarity reversal dc, which apparently did not get much attention until now. Interesting results on the effect of polarity transition time and applied polarity time step on the abovementioned distributions are addressed and presented. The pronounced effects of nonlinear conductivity on the time-dependent field distribution are also demonstrated. Furthermore, from the breakdown experiments conducted on tip-plane electrode system for different tip radii and applied time steps, the results put forward a rational and practical estimate of the breakdown field using the proposed model.

Polarization through the elastic scattering in magnetic field

There exists conceptual possibility to obtain the polarized beams of particles through their elastic scattering in magnetic field. Here such possibility is discussed with the use of classical spin models for, both, the cases of charged and neutral magneton. In the charged particle case the fundamental possibility to observe the effect stems from results of Novosibirsk experiment carried out in 1984. Within the proposed schematic design the polarization process lies in more rapid getting out from the trajectory of those particles which have “wrong” spin directions. For the charged particle the BMT and Frenkel models predict opposite Langevin-type polarizations and for the neutral particles the results obtained from the both are identical being consistent with the previous studies. Parameter [Formula: see text] (Sokolov–Ternov polarization time for electrons) is shown to emerge within the classical theory. The effect of noncomplete equilibrium polarization degree cannot be obtained in such model experiment since the kinetic process of the spin-flip transitions is left beyond the scheme considered. At that time the noninertial nature of motion entails in asymmetry between dependencies of spin–spin radiation rate on two horizontal spin components. This purely classical property is analyzed in the context of so-called “circular Unruh effect.”

Spin of Protons in NICA and PTR Storage Rings as an Axion Antenna

A new approach to search for axions in the storage ring experiments, applicable at a short coherence time of the in-plane polarization as is the case for protons is discussed. The technique can readily be applied at any storage ring equipped with internal polarimeter for the radial polarization of the beam (COSY, NICA, PTR). A possibility of substantial broadening of the range of attainable axion masses in storage rings with the hybrid electric and magnetic bending is pointed out, the PTR proton storage ring being an example.

Impact of Strong and Weak Stratospheric Polar Vortices on the Mesosphere and Lower Thermosphere

AbstractThe impact of strong and weak Northern Hemisphere stratospheric polar vortices on the zonal mean and atmospheric tides in the mesosphere and lower thermosphere (MLT) is investigated using Specified Dynamics Whole Atmosphere Community Climate Model (WACCM) with thermosphere‐ionosphere eXtension (SD‐WACCM‐X) simulations and Aura Microwave Limb Sounder observations. The observed and simulated zonal mean anomalies during strong and weak vortices are in good agreement. Zonal mean and tidal anomalies during weak polar vortex events are consistent with those known to occur during sudden stratospheric warmings. Generally opposite, though weaker, anomalies are found to occur when the stratospheric polar vortex is strong. The most notable impact in the MLT is a reduction in the migrating semidiurnal tide of ∼25%–35% during strong polar vortex times. The results demonstrate that, in addition to weak polar vortex events, a strong stratospheric polar vortex can also have an appreciable impact on the middle and upper atmosphere.

Middle Miocene-Pleistocene Magneto-Cyclostratigraphy from IODP Site U1501 in the Northern South China Sea

Site U1501 of International Ocean Discovery Program (IODP) Expedition 368 locates on a broad regional basement high in the northern margin of the South China Sea (SCS). This study refines the chronostratigraphy of the upper 160 m sedimentary succession from Hole U1501C using paleomagnetic measurements and cyclostratigraphic analysis on the Natural Gamma Radiation (NGR) data. Rock magnetic analysis displays that the magnetic signal of the sediments is mainly carried by single-domain (SD) and multi-domain (MD) magnetite. A total of 12 geomagnetic reversals are identified and correlated to the geomagnetic polarity time scale (GPTS) in Geologic Time Scale 2020 (GTS 2020), combining biostratigraphic data and planktonic foraminiferal oxygen records. The Milankovitch cycles of 405-kyr long orbital eccentricity, ∼100-kyr short orbital eccentricity, and obliquity cycles are identified in the NGR profile. A 15.54 Myr astronomical time scale is constructed by tuning the short eccentricity cycles filtered from the NGR profiles to the La2010 astronomical solution with the constraints of the magnetostratigraphic results, biostratigraphic age datum and planktonic foraminiferal oxygen records. This new high-resolution age model provides a new temporal constraint on the tectonic and paleoenvironmental evolution in the South China Sea.

Multipartite classically entangled scalar beams.

Classically entangled light is used to refer to a class of structured beams with space-polarization, polarization-time, and space-time non-separable states akin to entangled states, which enable novel quantum-analog methods and applications in structured light. Here, we argue that classical entanglement is also available for pure scalar beams with multiple non-separable spatial degrees of freedom (DoFs). We theoretically and experimentally demonstrate a class of scalar ray-wave structured light with multiple controllable local DoFs to emulate multipartite entangled states, including the Greenberger-Horne-Zeilinger states. Our work unveils a rich parameter space for high-dimensional and multi-DoF control of structured light to extend applications in classical-quantum regimes.

Numerical Investigation of Charge Packet Dynamics in Polyethylene Assuming Barrier Height-Electric Field Hysteresis Hypothesis

Charge packet phenomenon is a sign of the impending breakdown of the dielectric materials. In order to discuss the formation mechanism of charge packets, space charge characteriscs in polyethylene under the electric field of 150kV/mm are simulated based on the bipolar transport model assuming hysteresis in the barrier height for holes. It is found that if hysteresis in the barrier height is not introduced, net charge densities in the vicinity of the electrodes increase with the increase of polarization time. However, charge packets could not be reproduced without hysteresis hypothesis. When hysteresis loop in the barrier height are incorporated, charge packets are generated and propagated with the velocity about 3μm/s. The dying away of charge packets is not observed, which disagrees with the experimental data.

Full-Stokes polarization transformations and time sequence metasurface holographic display

With the development of micro/nano fabrication technology, metasurface holography has emerged as a revolutionary technology for the manipulation of light with excellent performance. However, for applications of full-Stokes polarization encryption and time sequence holographic display, multiplexing strategies of metasurfaces with large bandwidths and simple operations still need to be developed. As one of the most popular schemes of multiplexing, polarization multiplexed metasurfaces have shown flexible recording abilities for both free-space beam and surface waves. Here, by using a dielectric metasurface equipped with double phase holograms, we have achieved flexible polarization multiplexed transformations from one full-Stokes space to another. The vectorial hologram is optimized by a hybrid genetic algorithm and digitalized with subwavelength modulated units. Based on a quantitative map and remarkable information capacity, time sequence holographic display and complex optical encryption are experimentally demonstrated by changing input/output polarization channels in real time. We believe our method will facilitate applications in smart compact devices of dynamic display, dynamic optical manipulation, optical encryption, anticounterfeiting, etc.

Social Trust in Polarized Times: How Perceptions of Political Polarization Affect Americans' Trust in Each Other.

Most Americans think that the country is politically divided and polarization will only get worse, not better. Such perceptions of polarization are widespread, but we do not know enough about their effects, especially those unrelated to political variables. This study examines the consequences of perceived polarization for levels of social trust in the United States. Trust in fellow citizens is the backbone of a well-functioning democracy, given its role in promoting social cohesion and facilitating collective action. Using nationally representative panel data, as well as an original survey experiment, I find that perceived polarization directly undermines Americans’ trust in each other. A belief that members of society share common values fosters social trust, but perceptions of partisan divisions and polarization make people less trusting of their fellow citizens. Due to perceived polarization, people are less likely to believe that others can be trusted to do the right thing, which in turn decreases their willingness to cooperate for good causes. I discuss the implications of these findings for society’s ability to work together toward common goals.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11109-022-09787-1.

Seize the King

Reviewed by: Seize the King Jennifer A. Low Seize the King Presented by the Classical Theatre of Harlem at the Richard Rodgers Amphitheater, Marcus Garvey Park, New York, NY. 6–29 July 2021. Written by Will Power. Directed by Carl Cofield. Choreography by Tiffany Rea-Fisher. Scenic design by Christopher and Justin Swader. Lighting design by Alan C. Edwards. Costumes by Mika Eubanks. Sound design and music by Frederick Kennedy. With Ro Boddie (Richard the Duke), R. J. Foster (Hastings), Andrea Patterson (Queen Woodville), Alisha Espinosa (Lady Anne/Edward V), Carson Elrod (Buckingham); Daniela Funicello, Tracy Dunbar, Jenny Hegarty Freeman, Hannah Gross, and Alisa Gregory (dancers). New York has another Shakespeare in the Park, and its passion, intensity, and innovation rival that of the Public Theater’s summer stage in Joe Papp’s heyday. The Classical Theatre of Harlem has presented free theater each summer since 2013 at the Richard Rodgers Amphitheater, mounting such productions as Romeo and Juliet, The Tempest, and The Bacchae. This venue, a bandshell in Marcus Garvey Park in Harlem, underwent a renovation completed in 2011; it gained state-of-the-art lighting, sound hookups, and a wider stage that promoted a more intimate and direct relationship between performers and audience members. The Classical Theatre of Harlem is helmed by Producing Artistic Director Ty Jones, the Obie-award-winning actor best known for his role on the Starz show Power, and Associate Artistic Director Carl Cofield, who was recently named chair of the graduate acting program at NYU’s Tisch School of the Arts. The company’s stated mission is to tell stories through the lens of the African diaspora, combining original adaptations, music, and dance to present great classics of world literature. [End Page 156] From 6 July to 29 July 2021, the company presented the New York premiere of Will Power’s reimagining of Richard III. His play Seize the King is written in iambic pentameter but also very much in the American vernacular. Power is a playwright, actor, and rapper described as one of the pioneers and co-creators of hip hop theater. Having performed in the 1998 film Drylongso and on several television shows including Russell Simmons’s Def Poetry Jam, Power turned to playwriting, combining music, rhymed dialogue, and choreography in his dramas. Seize the King, first performed in 2018, seems to be a response to America’s political climate at that time: Power asserted in an interview that in times of polarization and dysfunction, “you have to go back to the past and imagine what those old stories are for today” (McVicker). Power’s play begins with the death of Edward IV, the king who re-ascends the throne shortly before the start of Shakespeare’s Richard III. Like Shakespeare, Power spotlights Richard’s skillful manipulation of allies and adversaries, creating a tighter and more muscular plotline by focusing on just six named characters. Power’s fluent verse echoed a myriad of dramatic lines from a range of Shakespeare plays. Early on, his Richard the Duke (Ro Boddie in this production) soliloquized, Now I am through with sloppy secondsSecond in line, second in command, second best, second born,No more, the hour now is mine. This Richard’s sentiments echo those of Shakespeare’s Edmund in King Lear, reiterating the word “second” as Shakespeare reiterates “base.” Power also makes frequent use of blunt, forthright American colloquialism; just as he works with the expression “sloppy seconds,” he later builds on the phrase “Kiss my ass.” When Elizabeth Woodville, the Queen, demands that Richard “Kiss my feet, and beg for forgiveness/Kiss it. Kiss it. Kiss it motherfucker!” (echoing Jean Genet’s bishop), Richard does so, only to be met with another demand: “Now kiss my ass.” “Ass” ups the ante of “feet” and, by turning in profile and sticking out her posterior, Queen Woodville (Andrea Patterson) showed she intended the phrase literally. Power then inverted the phrase, turning to the other meaning of “kiss my ass”—absolutely not. Richard kissed Queen Woodville’s posterior before us––down front and center-stage––in order to procure her signature, which was necessary to finalize the order that would make him Protector of...

Cause Marketing in a Time of Polarization

Abstract: The polarization of consumer reactions to many social causes today, such as women's rights, transgender rights, racial justice, climate change, and the environment, makes cause marketing riskier and more complex than it has been in the past. The research study reported here highlights the nature and importance of authenticity in messaging and provides data from 28 marketing professionals about how to do cause marketing effectively, avoiding pitfalls that may alienate consumers. The study finds that the characteristics of authenticity that marketing professionals find most important in today's environment of cause-related marketing efforts are different from the characteristics of authenticity in more general environments—those not related to these contemporary social causes. Moreover, cause marketing has become widespread in our economy and is a reflection of changes in values, mores, and attitudes in society. In spite of the risks of cause marketing, the professionals in this sample believe it is worth the effort.

Comparative study of electrooptic, dielectric, and structural properties of two glassforming antiferroelectric mixtures with a high tilt angle.

Vitrification of the antiferroelectric smectic-C_{A}^{*} phase is reported for the orthoconic mixture W-1000 and its new derivative W-356. The crystallization is not observed even upon slow cooling and the cold crystallization on subsequent heating is also absent. Molecular dynamics in the smectic phases of both mixtures is investigated down to 173K and the fragility parameters are determined from the temperature behavior of the α-process. X-ray diffraction is applied to compare the structural parameters of W-356 and W-1000 as well as to study the structural changes during the glass transition of the Sm-C_{A}^{*} phase. The evolution of the smectic layer order within the Sm-C_{A}^{*} glass is reported, while the correlation length of the short-range order in the smectic layers is shown to be almost constant below the glass transition temperature. Electrooptic properties of W-356: spontaneous polarization, tilt angle and switching time are determined and compared with these of W-1000. The observed differences between the properties of W-356 and W-1000 might be explained by the dimer formation of components with the -C≡N terminal group, present only in the W-356 mixture, and by the different structure of the aromatic molecular core in one of the W-356 components.

A Conversation with Elisabeth Niklasson

Elisabeth Niklasson is lecturer at the School of Geosciences at the University of Aberdeen. She holds two master’s degrees in Cultural Heritage and Computational Archaeology from Gothenburg University, and a PhD in Archaeology from Stockholm University. She has long been interested in the ethical and political aspects of archaeological heritage, particularly relating to contemporary identity politics. A core part of her research has focused on European heritage policies, studying the influence of European Union (EU) funding schemes on archaeology. She has also reflected critically on the reception of aDNA in archaeology. In recent years, she has expanded her focus to analyse uses of the past by populist and extreme right movements in Europe, making vital contributions to our understanding of heritage in times of political polarization.

Paleomagnetism, magnetostratigraphy, provenance, and tectonic setting of the Lower Cretaceous of nuclear southern Mexico

We studied the sedimentology, provenance, and paleomagnetism of Lower Cretaceous strata in nuclear southern Mexico deposited in continental, marginal and marine settings in order to better understand their tectonic setting and paleographic correlations. The studied units have been assigned to the Zicapa, Atzompa, Caltepec, Xonamanca, and Jaltepetongo formations, which are interpreted as an eastward-deepening paleogeography (in present day coordinates) deposited between Valanginian and Aptian time in a system of extensional basins contemporaneous with arc magmatism. Provenance interpreted from sandstone petrology, conglomerate clast counts, and detrital zircon U–Pb geochronology indicates that these successions consist of polymictic conglomerate, quartz-lithic metamorphoclastic and feldspathic-quartz lithic volcaniclastic sandstone, and mudstone. These were sourced from the underlying Precambrian and Paleozoic basement rocks, as well as from proximal suites of mafic to acid Jurassic (∼182-145 Ma), and Cretaceous volcanic rocks (∼140-123 Ma). The remanent magnetization in the Atzompa and Caltepec formations is multivectorial, and the characteristic remanent magnetization resides in hematite. For the Atzompa the grand mean is Dec = 335.3° and Inc = 25.4° (k = 15.4, α95 = 12.7°; N = 10 accepted sites). For the Caltepec the grand mean is Dec = 354.3°, Inc = 27.9° (k = 29.15, α95 = 6.1°, N = 20 accepted sites). Magnetizations in both units predate folding and pass reversal tests. For the uppermost Zicapa the magnetization is nearly univectorial and resides in a soft magnetic phase; the grand mean is D = 275.2°, I = 36.0° (k = 34.4, α95 = 10.1°, N = 7 accepted sites). For the Caltepec and Atzompa formations, I/E corrected directions indicate a paleolatitude of ∼20° to 23°N which is indistinguishable from that expected assuming stability with respect to the North America craton (∼24°), implying only minor tectonic motions since Early Cretaceous deposition, and demonstrating that the present distribution of units studied resembles their paleographic relations. The magnetostratigraphy of these units can be correlated with some confidence to the M10-M0r sequence of the geomagnetic polarity time scale, suggesting that the formations record late Valanginian and early Aptian marine transgressions that might correlate with global eustatic curves. The temporal and paleogeographic distribution of magmatism in southern Mexico is consistent with the presence of a continental arc formed by eastward subduction under the North American plate continuously from Early Jurassic to Aptian time, and extension in a back-arc setting during the Hauterivian-Barremian driven by slab rollback. We assign the system of extensional basins to the “southlands rift”, a short-lived event that predates amalgamation of oceanic terranes in the west and Albian carbonate platform development.

Teardown analysis and characterization of a commercial lithium-ion battery for advanced algorithms in battery electric vehicles

In recent years, in-depth analysis of the manifold properties of commercial lithium-ion batteries has gained increasing attention, as it fosters optimized design and operational strategies of battery-powered applications such as battery electric vehicles. However, various properties are not easily accessible and experimental determination requires intensive efforts in the battery lab. In this study, we have performed a tear-down analysis of a commercially available lithium-ion cell with a silicon-doped graphite anode and a Ni-rich NCA cathode. Enhanced by computed tomography (CT) scans, we reveal the cell’s internal geometrical properties. Furthermore, mini pouch half cells of the anode and cathode have been built to examine their electrochemical properties in context with full cell measurements. In particular, we examined the open circuit voltage with different measurement methods and for different temperatures and performed reconstruction of the full cell via fitting of electrode potentials. We give detailed insights into the kinetics of the cell by analyzing the distribution of relaxation times (DRT) calculated from electrochemical impedance spectroscopy (EIS). Individual loss processes are assigned to either electrode and their polarization resistances and time constants are quantified over a large SOC and temperature range. A comprehensive open-source dataset of the investigated cell is provided to propel international research activities in the development of advanced models and algorithms for lithium-ion batteries.

Repeatability of Polar Accumulation Time Series From Interannual Repeat Radar Echograms

Ice-penetrating radar is increasingly used to reconstruct surface mass balance (SMB) time series, but questions remain regarding the multi-year consistency of such measurements. We compare annually-resolved SMB time series reconstructed from airborne radar collected in 2011 and 2016 in order to assess the repeatability of radar-based estimates. We further compare results between the flights using a traditional manual method to determine annual layers and an automated probabilistic method. The results indicate low biases (2.98%–6.54%) between different collection times and methods with root-mean-square errors of 27.1%–36.5%. Overall bias distributions minimally differ based on collection time and reconstruction method, although specific sites can deviate more substantially. These results suggest that ice-penetrating radar can be used to reconstruct temporally stable annually-resolved SMB time series even when data collection is separated by several years. This outcome permits large syntheses of radar-derived SMB time series with less regard to homogeneous collection times.

Analysis of Earth’s polar motion and length of day trends in comparison with estimates using second degree stokes coefficients from satellite gravimetry

We analyzed the impacts of data span on trend estimates using Earth’s long-term polar motion time series, 1846-present, and using methodologies including singular spectrum analysis, and Panteleev’s filter to mitigate the time series containing transient signals. Our results show that the fluctuations of the mean rotational pole position, the Markowitz wobble, cannot be fully explained by the oceanic and atmospheric excitations. However, there exists plausible similarity with the variations of amplitudes of the Chandler wobble. To explain the abrupt deviation of the mean pole from the previous state after year 2000, we first compute Earth rotation excitations, using the temporal variations of the second-degree Stokes coefficients, C 21 , S 21 , estimated from GRACE, GRACE Follow-On and Satellite Laser Ranging (SLR), 2002–2021. We then compare their trend estimates with that of the Earth’s polar motion, and conclude that the drift of the pole is consistent with the climate-induced mass redistributions within the Earth system during the past two decades. However, the observed trend is not in exact agreement with the prediction values using contemporary glacial isostatic adjustment (GIA) process forward models. The analysis of the J 2 variations since 1976 from SLR and the corresponding length of day (LOD) changes, reveals a clear trend reversal around the year 2000. However, the observed J 2 variations can only explain ∼ 5 % of the long-term LOD changes. The remaining decadal signal in the LOD, usually accounted for by the angular momentum exchange at the core-mantle boundary, is observed to be anti-correlated with the Earth surface temperature anomaly. The geophysical explanation on these relationships remains elusive, and necessitates future studies.

Dual-polarization Sentinel-1 data polarization time series InSAR technology surface deformation monitoring—Taking shanghai pudong airport as an example

Dual-polarization Sentinel-1 data polarization time series InSAR technology surface deformation monitoring—Taking shanghai pudong airport as an example

Solvent-Dependent Excited-State Evolution of Prodan Dyes.

Excited-state character and dynamics of two 6-(dimethylamino)-2-acylnaphthalene dyes (Prodan and Badan-SCH2CH2OH) were studied by picosecond time-resolved IR spectroscopy (TRIR) in solvents of different polarity and relaxation times: hexane, CD3OD, and glycerol-d8. In all these solvents, near-UV excitation initially produced the same S1(ππ*) excited state characterized by a broad TRIR signal. A very fast decay (3, ∼100 ps) followed in hexane, whereas conversion to a distinct IR spectrum with a ν(C═O) band downshifted by 76 cm-1 occurred in polar/H-bonding solvents, slowing down on going from CD3OD (1, 23 ps) to glycerol-d8 (5.5, 51, 330 ps). The final relaxed excited state was assigned as planar Me2N → C═O intramolecular charge transfer S1(ICT) by comparing experimental and TDDFT-calculated spectra. TRIR conversion kinetics are comparable to those of early stages of multiexponential fluorescence decay and dynamic fluorescence red-shift. This work presents a strong evidence that Prodan-type dyes undergo solvation-driven charge separation in their S1 state, which is responsible for the dynamic fluorescence Stokes shift observed in polar/H-bonding solvents. The time evolution of the optically prepared S1(ππ*) state to the S1(ICT) final state reflects environment relaxation and solvation dynamics. This finding rationalizes the widespread use of Prodan-type dyes as probes of environment dynamics and polarity.

National Truth Commission in Brazil: the Thread of History and the Right to Memory and Truth

The article aims to problematize the issues of memory and Transitional Justice from the context of the establishment of the Brazilian National Truth Commission – (CNV, in Portuguese). The disputes about what to remember, how to remember, and what to forget (or not to forget) can become very complex in times of political polarization. By problematizing the Brazilian case between 2008 and 2014, we seek to highlight how the institution path of the CNV dealt with legislative and empirical obstacles around memory, history, forgetting, and resentment. Methodologically, the research used primary sources (legislative and judicial documents, reports, opinions) and secondary sources (specialized literature on the subject). Using the descriptive method, we present the Brazilian transitional context and the course of the CNV to demonstrate how the tension between resentment and the right to memory and the right to truth were organized by the Commission. While the outcome of the CNV Report is relevant, the accountability of human rights violators in Brazil is neutralized by the justice system. The promise of a public policy on memory remains in oblivion controlled by political elites.