Ext Abstr Hum Factors Computing Syst
April 2022
The last several years have seen a strong growth of telerobotic technologies with promising implications for many areas of learning. HCI has contributed to these discussions, mainly with studies on user experiences and user interfaces of telepresence robots. However, only a few telerobot studies have addressed everyday use in real-world learning environments.
View Article and Find Full Text PDFChorus waves play a key role in outer Van Allen electron belt dynamics through cyclotron resonance. Here, we use Van Allen Probes data to reveal a new and distinct population of intense chorus waves excited in the heart of the radiation belt during the main phase of geomagnetic storms. The power of the waves is typically ~ 2-3 orders of magnitude greater than pre-storm levels, and are generated when fluxes of ~ 10-100 keV electrons approach or exceed the Kennel-Petschek limit.
View Article and Find Full Text PDFJ Geophys Res Space Phys
February 2022
Loss mechanisms act independently or in unison to drive rapid loss of electrons in the radiation belts. Electrons may be lost by precipitation into the Earth's atmosphere, or through the magnetopause into interplanetary space-a process known as magnetopause shadowing. While magnetopause shadowing is known to produce dropouts in electron flux, it is unclear if shadowing continues to remove particles in tandem with electron acceleration processes, limiting the overall flux increase.
View Article and Find Full Text PDFJupiter's rapidly rotating, strong magnetic field provides a natural laboratory that is key to understanding the dynamics of high-energy plasmas. Spectacular auroral x-ray flares are diagnostic of the most energetic processes governing magnetospheres but seemingly unique to Jupiter. Since their discovery 40 years ago, the processes that produce Jupiter's x-ray flares have remained unknown.
View Article and Find Full Text PDFJ Geophys Res Space Phys
June 2021
Suprathermal electrons in the solar wind consist of the "halo," present at all pitch angles, and the "strahl" which is a field-aligned, beam-like population. Examining the heliospheric evolution of strahl beams is key to understanding the in-transit processing of solar wind suprathermal electrons, in particular, to identify electron scattering mechanisms and to establish the origin of the halo population. Not only does this have significant implications with regard to the kinetic processes occurring within the solar wind but also its thermodynamic evolution, as the suprathermal electrons carry the majority of the solar wind heat flux.
View Article and Find Full Text PDFThe substorm process releases large amounts of energy into the magnetospheric system, although where the energy is transferred to and how it is partitioned remains an open question. In this study, we address whether the substorm process contributes a significant amount of energy to the ring current. The ring current is a highly variable region, and understanding the energization processes provides valuable insight into how substorm-ring current coupling may contribute to the generation of storm conditions and provide a source of energy for wave driving.
View Article and Find Full Text PDFDuring geomagnetic substorms, stored magnetic and plasma thermal energies are explosively converted into plasma kinetic energy. This rapid reconfiguration of Earth's nightside magnetosphere is manifest in the ionosphere as an auroral display that fills the sky. Progress in understanding of how substorms are initiated is hindered by a lack of quantitative analysis of the single consistent feature of onset; the rapid brightening and structuring of the most equatorward arc in the ionosphere.
View Article and Find Full Text PDFRemoval of Sr from aqueous media presents particular challenges, especially in complex wastes such as nuclear industry liquors. Commercial sorbents while effective, can be highly expensive and subject to negative effects from competing ions. Here we evaluate two potential biosorbents (crab carapace and spent distillery grain) as potential alternatives and compare their performance to two commercial sorbents for Sr removal at industrially relevant concentrations (low mg/L).
View Article and Find Full Text PDFUltralow frequency (ULF) waves play a fundamental role in the dynamics of the inner magnetosphere and outer radiation belt during geomagnetic storms. Broadband ULF wave power can transport energetic electrons via radial diffusion, and discrete ULF wave power can energize electrons through a resonant interaction. Using observations from the Magnetospheric Multiscale mission, we characterize the evolution of ULF waves during a high-speed solar wind stream (HSS) and moderate geomagnetic storm while there is an enhancement of the outer radiation belt.
View Article and Find Full Text PDFSubstorm onset is marked in the ionosphere by the sudden brightening of an existing auroral arc or the creation of a new auroral arc. Also present is the formation of auroral beads, proposed to play a key role in the detonation of the substorm, as well as the development of the large-scale substorm current wedge (SCW), invoked to carry the current diversion. Both these phenomena, auroral beads and the SCW, have been intimately related to ultra-low frequency (ULF) waves of specific frequencies as observed by ground-based magnetometers.
View Article and Find Full Text PDFThe time scales of reconnection outflow, substorm expansion, and development of instabilities in the terrestrial magnetosphere are comparable, i.e., from several to tens of minutes, and their existence is related.
View Article and Find Full Text PDFWave-particle interactions play a crucial role in energetic particle dynamics in the Earth's radiation belts. However, the relative importance of different wave modes in these dynamics is poorly understood. Typically, this is assessed during geomagnetic storms using statistically averaged empirical wave models as a function of geomagnetic activity in advanced radiation belt simulations.
View Article and Find Full Text PDFWe report the first Jupiter X-ray observations planned to coincide with an interplanetary coronal mass ejection (ICME). At the predicted ICME arrival time, we observed a factor of ∼8 enhancement in Jupiter's X-ray aurora. Within 1.
View Article and Find Full Text PDFJ Geophys Res Space Phys
October 2015
We present the first multievent study of the spatial and temporal structuring of the aurora to provide statistical evidence of the near-Earth plasma instability which causes the substorm onset arc. Using data from ground-based auroral imagers, we study repeatable signatures of along-arc auroral beads, which are thought to represent the ionospheric projection of magnetospheric instability in the near-Earth plasma sheet. We show that the growth and spatial scales of these wave-like fluctuations are similar across multiple events, indicating that each sudden auroral brightening has a common explanation.
View Article and Find Full Text PDFJ Geophys Res Space Phys
July 2016
Substorms are fundamental and dynamic processes in the magnetosphere, converting captured solar wind magnetic energy into plasma energy. These substorms have been suggested to be a key driver of energetic electron enhancements in the outer radiation belts. Substorms inject a keV "seed" population into the inner magnetosphere which is subsequently energized through wave-particle interactions up to relativistic energies; however, the extent to which substorms enhance the radiation belts, either directly or indirectly, has never before been quantified.
View Article and Find Full Text PDFAt the beginning of the twentieth century, an anaesthetist could choose between nitrous oxide, chloroform, and ether (diethyl ether) for the induction of painrelieving unconsciousness. By the end of century, the choice was between a small number of fluorinated aliphatic ethers such as Enflurane, Desflurane, and Sevoflurane, and (in some jurisdictions) the rare gas, xenon. Between these endpoints researchers had identified a surprisingly broad range of hydrocarbons, noble gases, organohalogens, and aliphatic ethers that possessed anaesthetic properties.
View Article and Find Full Text PDFDuring substorm growth phases, magnetic reconnection at the magnetopause extracts ∼10 J from the solar wind which is then stored in the magnetotail lobes. Plasma sheet pressure increases to balance magnetic flux density increases in the lobes. Here we examine plasma sheet pressure, density, and temperature during substorm growth phases using 9 years of Cluster data (>316,000 data points).
View Article and Find Full Text PDFRationale: The worldwide generation of plastic electronic waste (e-waste) is reaching epic proportions. The presence of toxic brominated flame retardants (BFRs) within these materials limits their ability to be recycled, resulting in large amounts of e-waste reaching landfills.
Methods: Liquid extraction surface analysis mass spectrometry (LESA-MS) employing a chip-based nanoelectrospray coupled to a triple quadrupole mass spectrometer represents a novel control technology for directing e-waste streams for recycling.
J Geophys Res Space Phys
February 2014
Unlabelled: The substorm current wedge (SCW) is a fundamental component of geomagnetic substorms. Models tend to describe the SCW as a simple line current flowing into the ionosphere toward dawn and out of the ionosphere toward dusk, linked by a westward electrojet. We use multispacecraft observations from perigee passes of the Cluster 1 and 4 spacecraft during a substorm on 15 January 2010, in conjunction with ground-based observations, to examine the spatial structuring and temporal variability of the SCW.
View Article and Find Full Text PDFCarapace from the edible crab was assessed for the biosorption of Hg from aqueous solutions. Batch adsorption studies were used to determine the effects of contact time, pH, concentration, particle size and Cu(II) as a co-ion. The removal of Hg was fast and efficient, attaining >80.
View Article and Find Full Text PDFThis paper explores issues of governance and decision-making structures associated with the problem of hexachlorobenzene (HCB) waste at Botany in New South Wales. From a government perspective, the problem is 'downstream' of a well-known national controversy over whether Australia should have a high-temperature incinerator (HTI) to 'dispose' of such scheduled wastes. The 1992 decision not to proceed with HTI followed an extensive process of public consultation, which, against the expectations of industry and government, saw the emergence of Australia-wide community opposition.
View Article and Find Full Text PDFMagnetospheric substorms explosively release solar wind energy previously stored in Earth's magnetotail, encompassing the entire magnetosphere and producing spectacular auroral displays. It has been unclear whether a substorm is triggered by a disruption of the electrical current flowing across the near-Earth magnetotail, at approximately 10 R(E) (R(E): Earth radius, or 6374 kilometers), or by the process of magnetic reconnection typically seen farther out in the magnetotail, at approximately 20 to 30 R(E). We report on simultaneous measurements in the magnetotail at multiple distances, at the time of substorm onset.
View Article and Find Full Text PDFIn the ozone fervour of the mid-nineteenth century, the ability of ether, turpentine, and other unsaturated oils to take up oxygen was construed in terms of ozone, and the products were styled "ozonised ether" and "ozonised oils." Their undoubted oxidising power led to their use as disinfectants, notably by Dr. John Day in Australia, and Charles Kingzett in England and later America.
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