bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal and Interannual Variations of Sea Ice Mass Balance From the Central Arctic to the Greenland Sea
Authors: Lei Ruibo , Cheng Bin , Heil Petra , Vihma Timo , Wang Jia , Ji Qing , Zhang Zhanhai 
Published: March 2018

AbstractThe seasonal evolution of sea ice mass balance between the Central Arctic and Fram Strait, as well as the underlying driving forces, remain largely unknown because of a lack of observations. In this study, two and three buoys were deployed in the Central Arctic during the summers of 2010 and 2012, respectively. It was established that basal ice growth commenced between mid‐October and early December. Annual basal ice growth, ranging from 0.21 to 1.14 m, was determined mainly by initial ice thickness, air temperature, and oceanic heat flux during winter. An analytic thermodynamic model indicated that climate warming reduces the winter growth rate of thin ice more than for thick ice because of the weak thermal inertia of the former. Oceanic heat flux during the freezing season was 2–4 W m−2, which accounted for 18–31% of the basal ice energy balance. We identified two mechanisms that modified the oceanic heat flux, i.e., solar energy absorbed by the upper ocean during summer, and interaction with warm waters south of Fram Strait; the latter resulted in basal ice melt, even in winter. In summer 2010, ice loss in the Central Arctic was considerable, which led to increased oceanic heat flux into winter and delayed ice growth. The Transpolar Drift Stream was relatively weak in summer 2013. This reduced sea ice advection out of the Arctic Ocean, and it restrained ice melt because of the cool atmospheric conditions, weakened albedo feedback, and relatively small oceanic heat flux in the north.
New Evidence of Breakpoint Forced Long Waves: Laboratory, Numerical, and Field Observations
Authors: Moura T. , Baldock T. E. 
Published: March 2018

AbstractNumerical modeling and analysis of laboratory and field data are combined to show new evidence of breakpoint forced long waves. The laboratory data and numerical modeling show that the breakpoint can oscillate at frequencies not directly linked to the wave group envelope for specific bichromatic wave groups. The breakpoint therefore oscillates at frequencies where incident bound long waves are not present, enabling direct identification of breakpoint forced waves. Spectral analysis and cross‐shore wave propagation patterns indicate that the breakpoint forced waves occur at subharmonic wave groups frequencies, the repeat frequency of the short waves within the group, and at frequencies associated with triad interactions. The results indicate that in this case the long waves are generated by breakpoint forcing rather than by energy transfer during shoaling of the incident waves. The slowly varying shape of the short waves in the groups and wave merging at the breakpoint controls the modulation of the breakpoint in these cases. The spectral analysis is applied to two field data sets where the breakpoint oscillation, incident waves and shoreline oscillation were measured, and infragravity wave generation is again identified at discrete frequencies that are not present in the incident wave group envelope, with merging of waves at the breakpoint again evident. The magnitudes of the generated infragravity waves outside the surf zone are also dependent on the normalized surf zone width. Both sets of observations provide further evidence for the generation of infragravity waves by the breakpoint forcing mechanism in the field.
Spatial Variability of Sediment Transport Processes Over Intratidal and Subtidal Timescales Within a Fringing Coral Reef System
Authors: Pomeroy Andrew W. M. , Lowe Ryan J. , Ghisalberti Marco , Winter Gundula , Storlazzi Curt , Cuttler Michael 
Published: March 2018

AbstractSediment produced on fringing coral reefs that is transported along the bed or in suspension affects ecological reef communities as well as the morphological development of the reef, lagoon, and adjacent shoreline. This study quantified the physical process contribution and relative importance of sea‐swell waves, infragravity waves, and mean currents to the spatial and temporal variability of sediment in suspension. Estimates of bed shear stresses demonstrate that sea‐swell waves are the key driver of the suspended sediment concentration (SSC) variability spatially (reef flat, lagoon, and channels) but cannot fully describe the SSC variability alone. The comparatively small but statistically significant contribution to the bed shear stress by infragravity waves and currents, along with the spatial availability of sediment of a suitable size and volume, is also important. Although intratidal variability in SSC occurs in the different reef zones, the majority of the variability occurs over longer slowly varying (subtidal) timescales, which is related to the arrival of large swell waves at a reef location. The predominant flow pathway, which can transport suspended sediment, consists of cross‐reef flow across the reef flat that diverges in the lagoon and returns offshore through channels. This pathway is primarily due to subtidal variations in wave‐driven flows but can also be driven alongshore by wind stresses when the incident waves are small. Higher frequency (intratidal) current variability also occurs due to both tidal flows and variations in the water depth that influence wave transmission across the reef and wave‐driven currents.
Using Stereo Satellite Imagery to Account for Ablation, Entrainment, and Compaction in Volume Calculations for Rock Avalanches on Glaciers: Application to the 2016 Lamplugh Rock Avalanche in Glacier Bay National Park, Alaska
Authors: Bessette‐Kirton Erin K. , Coe Jeffrey A. , Zhou Wendy 
Published: March 2018

AbstractThe use of preevent and postevent digital elevation models (DEMs) to estimate the volume of rock avalanches on glaciers is complicated by ablation of ice before and after the rock avalanche, scour of material during rock avalanche emplacement, and postevent ablation and compaction of the rock avalanche deposit. We present a model to account for these processes in volume estimates of rock avalanches on glaciers. We applied our model by calculating the volume of the 28 June 2016 Lamplugh rock avalanche in Glacier Bay National Park, Alaska. We derived preevent and postevent 2‐m resolution DEMs from WorldView satellite stereo imagery. Using data from DEM differencing, we reconstructed the rock avalanche and adjacent surfaces at the time of occurrence by accounting for elevation changes due to ablation and scour of the ice surface, and postevent deposit changes. We accounted for uncertainties in our DEMs through precise coregistration and an assessment of relative elevation accuracy in bedrock control areas. The rock avalanche initially displaced 51.7 ± 1.5 Mm3 of intact rock and then scoured and entrained 13.2 ± 2.2 Mm3 of snow and ice during emplacement. We calculated the total deposit volume to be 69.9 ± 7.9 Mm3. Volume estimates that did not account for topographic changes due to ablation, scour, and compaction underestimated the deposit volume by 31.0–46.8 Mm3. Our model provides an improved framework for estimating uncertainties affecting rock avalanche volume measurements in glacial environments. These improvements can contribute to advances in the understanding of rock avalanche hazards and dynamics.
The Effect of IMF Fluctuations on the Subsolar Magnetopause Position: A Study Using a Global MHD Model
Authors: Bonde R. E. F. , Lopez R. E. , Wang J. Y. 
Published: March 2018

AbstractDuring southward interplanetary magnetic field (IMF) conditions, the subsolar magnetopause moves inward even under steady solar wind pressure. This is generally referred to as “erosion.” Empirical and computational studies have been conducted to quantify the effect of magnetopause erosion; however, they generally use steady state IMF conditions. Solar wind conditions are not usually constant for very long, especially during such conditions as are present in high‐speed streams, which typically have large fluctuations in the IMF. These IMF fluctuations can occur on a range of times scales and amplitudes, resulting in a series of northward and southward IMF intervals imposed on the magnetosphere. We have simulated the effect of such IMF variations on the magnetopause position using a global magnetohydrodynamic model. We find that there are both time lag and hysteresis‐like effects on the motion of the magnetopause due to the variation in the magnitude of the southward IMF and that the instantaneous position of the magnetopause can be significantly different from what one would expect from steady state conditions.
High‐Citation Papers in Space Physics: Examination of Gender, Country, and Paper Characteristics
Authors: Moldwin Mark B. , Liemohn Michael W. 
Published: March 2018

AbstractThe number of citations to a refereed journal article from other refereed journal articles is a measure of its impact. Papers, individuals, journals, departments, and institutions are increasingly judged by the impact they have in their disciplines, and citation counts are now a relatively easy (though not necessarily accurate or straightforward) way of attempting to quantify impact. This study examines papers published in the Journal of Geophysical Research—Space Physics in the year 2012 (n = 705) and analyzes the characteristics of high‐citation papers compared to low‐citation papers. We find that high‐citation papers generally have a large number of authors (>5) and cite significantly more articles in the reference section than low‐citation papers. We also examined the gender and country of institution of the first author and found that there is not a statistically significant gender bias, but there are some significant differences in citation statistics between articles based on the country of first‐author institution.
Looking Beyond the Powder/Dense Flow Avalanche Dichotomy
Authors: Faug T. , Turnbull B. , Gauer P. 
Published: March 2018

AbstractKöhler et al. (2018, https://doi.org/10.1002/2017JF004375) deploy a high spatial and temporal resolution GEODAR radar system to reveal the inside of snow avalanches over the entire slope. They detect a rich variety of longitudinal and slope normal flow structures across a data set of 77 avalanches recorded over 6 years. Distinctive features in the radar signatures permit the definition of seven flow regimes and three distinct stopping signatures, illustrating behaviors much richer than the conventional dichotomy between dense flow avalanches and powder snow avalanches. This presents modelers with the challenge of exploring the physics of these regimes, the transitions between them and their relationship with the surrounding conditions.
Distributed Student's t filtering algorithm for heavy‐tailed noises
Authors: Xu Chen , Zhao Shunyi , Huang Biao , Liu Fei 
Published: March 2018

SummaryIn this paper, a distributed Student's t filtering algorithm to deal with heavy‐tailed noises is developed. In the traditional Kalman filter, the distribution of the signal is assumed. However, in reality, outliers in the signal are often encountered for which the assumption of Gaussian distribution is no longer valid. The Student's t distribution can describe noises in the presence of outliers. As a result, the weight on each data point within the filter adapts to the data quality so that the filter becomes insensitive to the outliers. We first derive the distributed filtering algorithm from the centralized Student's t filter, which is able to handle heavy‐tailed noises such as outliers and then analyze properties of the proposed method. It is shown that the proposed algorithm provides the same accuracy as the centralized Student's t filtering with no performance loss. Furthermore, the distributed Student's t filtering with feedback is developed, which is in accordance with centralized filtering, and the local error covariance is reduced as expected. Two numerical examples support the theoretical results and illustrate the validity of the proposed method.
Hybrid Plasmonic and Pyroelectric Harvesting of Light Fluctuations
Authors: Shiran Chaharsoughi Mina , Tordera Daniel , Grimoldi Andrea , Engquist Isak , Berggren Magnus , Fabiano Simone , Jonsson Magnus P. 
Published: March 2018

AbstractState‐of‐the‐art solar energy harvesting systems based on photovoltaic technology require constant illumination for optimal operation. However, weather conditions and solar illumination tend to fluctuate. Here, a device is presented that extracts electrical energy from such light fluctuations. The concept combines light‐induced heating of gold nanodisks (acting as plasmonic optical nanoantennas), and an organic pyroelectric copolymer film (poly(vinylidenefluoride‐co‐trifluoroethylene)), that converts temperature changes into electrical signals. This hybrid device can repeatedly generate current pulses, not only upon the onset of illumination, but also when illumination is blocked. Detailed characterization highlights the key role of the polarization state of the copolymer, while the copolymer thickness has minor influence on performance. The results are fully consistent with plasmon‐assisted pyroelectric effects, as corroborated by combined optical and thermal simulations that match the experimental results. Owing to the tunability of plasmonic resonances, the presented concept is compatible with harvesting near infrared light while concurrently maintaining visible transparency.
Epsilon‐Near‐Zero Photonics: A New Platform for Integrated Devices
Authors: Niu Xinxiang , Hu Xiaoyong , Chu Saisai , Gong Qihuang 
Published: March 2018

AbstractEpsilon‐near‐zero (ENZ) photonics is the study of light–matter interactions in the presence of structures with near‐zero permittivity and has been emerging as an important field of research in recent years. The introduction of zero permittivity structures also introduces a number of unique features to traditional photonic systems, including decoupling of their spatial and temporal field variations, tunneling through arbitrary channels, constant phase transmission, strong field confinement, and ultrafast phase transitions. Along with the continued developments in the theoretical research on ENZ photonics, many novel functional photonic devices are proposed and demonstrated experimentally, thus indicating the broad prospects of ENZ photonics for fabrication of high‐performance integrated photonic chips. Zero‐epsilon materials, which represent a singular point in optical materials, are expected to lead to remarkable developments in the fields of integrated photonic devices and optical interconnections. This review summarizes the underlying principles, the related novel physical effects, the fundamental principles for realization of ENZ photonic systems, and the integrated device applications of ENZ photonics. The review concludes with a brief overview of the challenges to be confronted and the potential development directions that may be pursued to realize extensive applications of ENZ photonics in the field of integrated photonic signal processing.
Light‐Induced Charge Separation in Mixed Electronic/Ionic Semiconductor Driving Lithium‐Ion Transfer for Photo‐Rechargeable Electrode
Authors: Andriamiadamanana Christian , Sagaidak Iryna , Bouteau Gaspard , Davoisne Carine , Laberty‐Robert Christel , Sauvage Frédéric 
Published: March 2018

AbstractLi‐ion batteries need to be regularly recharged, requiring chargers and connection to the grid to reverse the lithium‐ion transfer. Autonomous power sources independent of the electrical infrastructure are desired. A strategy to develop continuously functioning Li‐ion batteries is focused on a new architecture of electrodes which are capable of both harvesting light energy and storing it. One possible way to achieve this lies in a study aimed at evaluating whether lithium ions can display mobility inside a crystal structure upon light absorption, as in analogy to the dissociation process of excitons. Herein, it is demonstrated that by using LixTiO2 nanoparticles, bandgap excitation can induce a quantitative Li‐ion deinsertion reaction by the free holes generated. The half‐electrochemical cells containing these mesoporous lithiated TiO2 can be fully oxidized in only 1 h of light exposure. It displays close to 3 V open‐circuit potential under light and electrical load, and, provides a constant output power under fluctuating light conditions. Such an approach has the potential, when integrated into a fully regenerative device containing a suitable counter electrode, to generate energy during both day and night, thus having the potential to close the gap between electrochemical energy storage batteries and energy conversion photovoltaics.
High Temperature Polymer Electrolyte Membrane Fuel Cells for Integrated Fuel Cell – Methanol Reformer Power Systems: A Critical Review
Authors: Zhang Jin , Xiang Yan , Lu Shanfu , Jiang San Ping 
Published: March 2018

AbstractThe development of reliable power sources is important for the continuous operation of various electric equipment in unmanned aircraft and the field environment. Currently electric power delivery to such systems is mainly by battery packs. An alternative is to use fuel cells (FCs). FCs are electrochemical devices that are used to convert chemical energy of fuels such as hydrogen and methanol to electricity. Methanol is an attractive fuel because it is liquid at ambient temperature, has a much higher energy density than hydrogen and low reforming temperature (220–300 °C). Thus, integration of methanol steam reformers (MSRs) with FCs makes it possible to continuously produce electricity. The key challenge in such power system is the development of fuel cells which can be effectively operated at compatible temperature range of MSR, i.e., 220–300 °C in order to increase synergetic heat integration and system reliability. Herein, the latest development of high temperature polymer electrolyte membrane fuel cells (HT‐PEMFCs) is critically reviewed. The prospect of the integrated HT‐PEMFCs‐MSR as a reliable and compact power source is discussed. The results indicate that phosphoric acid doped polybenzimidazole (PA/PBI) membranes with in situ formed phosphosilicate nanocluster proton carriers show the technical feasibility of the development of HT‐PEMFCs at temperatures of 200–300 °C.
Densification by Compaction as an Effective Low‐Cost Method to Attain a High Areal Lithium Storage Capacity in a CNT@Co3O4 Sponge
Authors: Chen Yijun , Wang Yunsong , Wang Zhipeng , Zou Mingchu , Zhang Hui , Zhao Wenqi , Yousaf Muhammad , Yang Liusi , Cao Anyuan , Han Ray P. S. 
Published: March 2018

AbstractAchieving a high areal capacity is essential for the transfer of outstanding laboratory electrode results to commercial applications and also to ensure there exists a capacity matched cathode and anode for a properly tuned battery. Despite intensive efforts, most electrode materials exhibit areal capacities lower than that of the graphite anodes (4 mA h cm−2). An effective and low‐cost approach is reported to attain a high areal capacity via an intense densification by compacting a porous carbon nanotube sponge grafted with Co3O4 nanoparticles. The hybrid sponge can be compacted to a large degree (up to a tenfold densification) while still keeping its structural integrity and the 3D porous network. This method allows achieving a mass loading of up ‑to 14.3 mg cm−2 and an areal capacity of 12 mA h cm−2 (at a current density of 200 mA g−1) together with a gravimetric capacity of >800 mA h g−1. This densification by compaction approach offers an effective and low‐cost strategy to develop high mass loading and areal capacity electrodes for practical energy storage systems.
RuII‐Catalyzed Regioselective Debrominative Annulation Reaction of Salicylaldehydes and Propargyl Bromide: Synthesis of 2‐Methylchromones
Authors: Borthakur Somadrita , Kaishap Partha P. , Gogoi Sanjib 
Published: March 2018

AbstractA new method for the annulation reaction of salicylaldehydes with propargyl bromide is described. This RuII‐catalyzed annulation reaction provides 2‐methylchromones, which are a substructure of many biologically active natural products. The annulation reaction could be further extended to the synthesis of 2‐methylfuran‐fused compounds.
Plasmonic Hotspots in Air: An Omnidirectional Three‐Dimensional Platform for Stand‐Off In‐Air SERS Sensing of Airborne Species
Authors: Phan‐Quang Gia Chuong , Lee Hiang Kwee , Teng Hao Wen , Koh Charlynn Sher Lin , Yim Barnabas Qinwei , Tan Eddie Khay Ming , Tok Wee Lee , Phang In Yee , Ling Xing Yi 
Published: March 2018

AbstractMolecular‐level airborne sensing is critical for early prevention of disasters, diseases, and terrorism. Currently, most 2D surface‐enhanced Raman spectroscopy (SERS) substrates used for air sensing have only one functional surface and exhibit poor SERS‐active depth. “Aerosolized plasmonic colloidosomes” (APCs) are introduced as airborne plasmonic hotspots for direct in‐air SERS measurements. APCs function as a macroscale 3D and omnidirectional plasmonic cloud that receives laser irradiation and emits signals in all directions. Importantly, it brings about an effective plasmonic hotspot in a length scale of approximately 2.3 cm, which affords 100‐fold higher tolerance to laser misalignment along the z‐axis compared with 2D SERS substrates. APCs exhibit an extraordinary omnidirectional property and demonstrate consistent SERS performance that is independent of the laser and analyte introductory pathway. Furthermore, the first in‐air SERS detection is demonstrated in stand‐off conditions at a distance of 200 cm, highlighting the applicability of 3D omnidirectional plasmonic clouds for remote airborne sensing in threatening or inaccessible areas.
Exacerbation of Murine Experimental Autoimmune Myositis by Toll‐Like Receptor 7/8
Authors: Sciorati Clara , Monno Antonella , Doglio Maria Giulia , Rigamonti Elena , Ascherman Dana P. , Manfredi Angelo A. , Rovere‐Querini Patrizia 
Published: March 2018

ObjectiveToll‐like receptor 7 (TLR‐7), TLR‐8, and interferon (IFN)–induced genes are expressed in patients with idiopathic inflammatory myositis. This study was undertaken to investigate whether their activation influences the natural history of the disease.MethodsExperimental autoimmune myositis was induced in mice by injection of the amino‐terminal portion of the murine histidyl–transfer RNA synthetase (HisRS). Disease was compared in the presence or the absence of the TLR‐7/8 agonist R‐848 in wild‐type mice and in mice that fail to express the IFNα/β receptor (IFNα/βR‐null mice).ResultsExperimental autoimmune myositis induced by a single intramuscular immunization with HisRS spontaneously abated after 7–8 weeks. In contrast, levels of anti‐HisRS autoantibodies, endomysial/perimysial leukocyte infiltration, and myofiber regeneration persisted at the end of the follow‐up period (22 weeks after immunization) in mice immunized with HisRS in the presence of R‐848. Myofiber major histocompatibility complex (MHC) class I molecules were detectable only in mice immunized with both HisRS and R‐848. MHC up‐regulation occurred early and in muscles that were not directly injected with HisRS. Muscle MHC expression paralleled with leukocyte infiltration. MHC class I molecules were selectively up‐regulated in myotubes challenged with R‐848 in vitro. Type I IFN was necessary for the prolonged autoantibody response and for the spreading of the autoimmune response, as demonstrated using IFNα/βR‐null mice. Muscle infiltration was maintained in the injected muscle up to the end of the follow‐up period.ConclusionTLR‐7/8 activation is necessary to induce and maintain a systemic autoimmune response targeting the skeletal muscle. This experimental autoimmune myositis model reproduces many characteristics of human idiopathic inflammatory myopathies and may represent a tool for preclinical studies.