bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heat Flow in Southern Australia and Connections With East Antarctica
Authors: Pollett Alicia , Hasterok Derrick , Raimondo Tom , Halpin Jacqueline A. , Hand Martin , Bendall Betina , McLaren Sandra 
Published: October 2019

Key Points

First heat flow measurements from the Coompana Province, southern Australia, indicate values of 40–70 mW/m2 (57 ± 3 mW/m2 average)
A tectonically reconstructed heat flow map constrains the thermal regime of geological provinces formerly contiguous with East Antarctica
Geophysical models of Antarctic heat flow are likely underestimating crustal sources of radiogenic heat that influence subglacial melting
The Effect of Earthquake Kinematics on Tsunami Propagation
Authors: Williamson A. , Melgar D. , Rim D. 
Published: October 2019

AbstractTsunamis are one of the most destructive effects of subduction zone earthquakes. Directly observing and understanding the generation and propagation of tsunamis remains challenging due to limited offshore instrumentation and a sparse catalog of large events. This makes linking characteristics of the earthquake rupture to their effect on tsunami generation difficult. While past studies explored how varying earthquake source geometries affect tsunami nucleation, little has been done to examine the role of the kinematic component of rupture on the tsunami; we explore these effects in this study. While past studies have examined the kinematic effect using coastal tide gauge data, we expand this examination to more recent pressure gauges. We identify a consistent rotation of the main beam of tsunami energy when using a kinematic model, affecting far‐field hazards. We also identify a delay in tsunami arrival times at both coastal and open‐ocean gauges that can be as long as the total source duration. For large earthquakes, this delay introduces nonnegligible mapping errors when employing open‐ocean tsunami data for source characterizations. As a result of our findings we recommend including a kinematic component to tsunami modeling when studying events with source durations over 120 s and using recordings from open‐ocean pressure gauges. We also find that when focusing purely on coastal gauge data and near‐source hazards, the kinematic component is a much smaller contribution to the source uncertainty and can be ignored.
A Thick Negative Polarity Anomaly in a Sediment Core From the Central Arctic Ocean: Geomagnetic Excursion Versus Reversal
Authors: Liu Jianxing , Shi Xuefa , Liu Yanguang , Liu Qingsong , Liu Yan , Zhang Qiang , Ge Shulan , Li Jinhua 
Published: October 2019

AbstractThere are two distinctly different views on Quaternary sedimentation rates in the central Arctic Ocean, namely, that they were on cm/kyr or on mm/kyr scales, largely as a result of divergent interpretations of magnetic reversal stratigraphy. This study provides new evidence to help resolve this controversy in the form of an almost 1‐m‐thick negative polarity interval located at ~1.15 m below the seafloor in a 4.15‐m‐long sediment core from the Lomonosov Ridge, central Arctic Ocean. This thick polarity anomaly was first revealed through alternating field demagnetization of natural remanent magnetization on u‐channel samples. It was subsequently confirmed to be an authentic signal of a syndepositional geomagnetic field by integrating detailed rock magnetic studies, transmission electron microscopy with energy‐dispersive X‐ray spectroscopy analyses of magnetic extracts, and both alternating field and thermal demagnetization of discrete paleomagnetic samples. Here we conclude that it is more reasonable to interpret the reversed interval as a record of the Matuyama Chron rather than a Brunhes‐aged excursion, which yields mean sedimentation rates of ~1.5 mm/kyr and ~0.5 mm/kyr in the Brunhes and Matuyama Chrons, respectively. These estimates are remarkably lower than assumed in most recent studies, but in good agreement with both previous magnetostratigraphic and recent geochemical studies relative to the decay of Be and U‐series isotopes, which might indicate “sediment‐starved” environments at least in some parts of this region. Overall, our results not only imply that chronostratigraphy in the central Arctic Ocean remains open to debate but also warrant further investigations in this microfossil‐barren region.
Meridional and Zonal Eddy‐Induced Heat and Salt Transport in the Bay of Bengal and Their Seasonal Modulation
Authors: Gonaduwage Lasitha Perera , Chen Gengxin , McPhaden Michael J. , Priyadarshana Tilak , Huang Ke , Wang Dongxiao 
Published: October 2019

AbstractThis study investigates basin and regional‐scale eddy (turbulent)‐induced heat and salt transport associated with mesoscale eddies of the Bay of Bengal (BOB). A high level of eddy‐induced transport is found in four subregions: the western boundary of the northern BOB (NB), the western BOB (WB), the southwestern BOB near Sri Lanka (SWB), and the southeastern BOB (SEB). The main seasons for eddy‐induced heat transport in the NB and SWB are identified as the presummer (March to April) and summer monsoon (May to September) seasons, whereas the postsummer monsoon season (October to November) is the main season for the WB and SEB. It is found that not only meridional but also zonal eddy‐induced transport is significant, due to the semienclosed nature of the BOB, which restricts poleward transport in the northern part of the bay. An analysis of upper‐layer eddy energetics reveals that the main contributor to the increased eddy kinetic energy and thus the transport is baroclinic instability in the NB, SWB, and WB, while both barotropic and baroclinic instability are important in the SEB. Using a 2.5‐layer reduced gravity model, baroclinic instability in the NB, SWB, and SEB is further investigated. The results reveal that strong vertical velocity shear and weak stratification are essential for generating baroclinic instability, which enhances the seasonal eddy‐induced transport in the respective subregions.
Impact of Approach Angle of an Impinging Cyclone on Generation of Storm Surges and Its Interaction with Tides and Wind Waves
Authors: Pandey Smita , Rao A. D. 
Published: October 2019

AbstractDetailed investigation is made on the effect of cyclone's approach angle on generation of storm surges and its nonlinear interaction with tides and wind waves using a standalone 2DDI ADCIRC and a coupled ADCIRC+SWAN model. Numerical experiments are executed using 17 idealized straight cyclone tracks of same intensity moving at constant forward speed. The study domain considers an idealized bathymetry with straight coastline and uniform shelf width. All cyclones make landfall at the same location with angles approaching from 10° to 170° with an increment of 10°. The simulations show that the maximum storm surge is computed for tracks land falling with 60o–90o. Increase in the peak storm surge is seen about 15% from 10o–60o, while it decreases by about 13% from 90o–170o. Surge‐wave interaction modifies the maximum water level by about 21–26%. The maximum wave contribution is seen for track with 90o followed by 160o and 20o. During different phases of tide, surge‐tide interaction modifies peak surge, its occurrence, and location as cyclone makes landfall at different angles. The extent of affected coastal stretch is maximum on either side of the landfall for the tracks moving close to the coast, while it is minimum for the perpendicular track (90o), confined only to the right of the landfall. The peak surge‐tide‐wind wave interaction along the coast at both high and low tide is seen about 2–4 hr after the landfall. The interaction along the coast depends on approach angles of the cyclone; however, the total water level is mainly modified by both tidal phase and approach angle.
Five‐Year Measurements of Net Ecosystem CO2 Exchange at a Fen in the Zoige Peatlands on the Qinghai‐Tibetan Plateau
Authors: Liu Xinwei , Zhu Dan , Zhan Wei , Chen Huai , Zhu Qiuan , Hao Yanbin , Liu Wenjun , He Yixin 
Published: October 2019

AbstractLittle is known about the relationship between carbon sequestration and environment in some alpine peatland ecosystems, especially in remote areas such as the Qinghai‐Tibetan Plateau. In the present study, net ecosystem CO2 exchange (NEE) flux was measured from 2013 to 2017 at the Riganqiao fen in the Zoige peatlands on the eastern Qinghai‐Tibetan Plateau using the eddy covariance technique. In the growing season, diurnal CO2 uptake peaks occurred between 12:00 and 14:00, while emission peaks occurred between 21:00 and 22:00. Carbon uptake peak occurred mainly from June to July in the growing season, and the maximum daily net CO2 uptake of −8.4 g C m−2 d−1 was observed in mid‐June 2016. The Riganqiao peatland was a net CO2 sink, with uptake (g C m−2 yr−1) of average −171.4 ± 38.1 during the five years. Photosynthetically active radiation (PAR) and soil temperature (Ts) were significantly correlated with diurnal net CO2 uptake. In growing seasons, PAR was significantly correlated with daytime CO2 uptake, and Ts was a major determinant of ecosystem respiration during growing and nongrowing seasons, although the fitting functions differed between the two seasons. Rainfall influenced interannual variability of cumulative NEE and water table depth (WTD) and volumetric water content (VWC) were both significantly correlated with interannual NEE. Our results suggest that in the long term, peatland NEE is affected mainly by the water regime, which is influenced by soil temperature and water condition.
Hypervelocity Impact Experiments in Iron‐Nickel Ingots and Iron Meteorites: Implications for the NASA Psyche Mission
Authors: Marchi S. , Durda D.D. , Polanskey C.A. , Asphaug E. , Bottke W.F. , Elkins‐Tanton L.T. , Garvie L.A.J. , Ray S. , Chocron S. , Williams D.A. 
Published: October 2019

AbstractThe National Aeronautics and Space Administration (NASA) Psyche mission will visit the 226‐km diameter main belt asteroid (16) Psyche, our first opportunity to visit a metal‐rich object at close range. The unique and poorly understood nature of Psyche offers a challenge to the mission as we have little understanding of the surface morphology and composition. It is commonly accepted that the main evolutionary process for asteroid surfaces is impact cratering. While a considerable body of literature is available on collisions on rocky/icy objects, less work is available for metallic targets with compositions relevant to Psyche. Here we present a suite of impact experiments performed at the NASA Ames Vertical Gun Range facility on several types of iron meteorites and foundry‐cast ingots that have similar Fe‐Ni compositions as the iron meteorites. Our experiments were designed to better understand crater formation (e.g., size, depth), over a range of impact conditions, including target temperature and composition. We find that the target strength, as inferred from crater sizes, ranges from 700 to 1,300 MPa. Target temperature has measurable effects on strength, with cooled targets typically 10–20% stronger. Crater morphologies are characterized by sharp, raised rims and deep cavities. Further, we derive broad implications for Psyche's collisional evolution, in light of available low resolution shape models. We find that the number of large craters (>50 km) is particularly diagnostic for the overall bulk strength of Psyche. If confirmed, the number of putative large craters may indicate that Psyche's bulk strength is significantly reduced compared to that of intact iron meteorites.
Anomalous Phyllosilicate‐Bearing Outcrops South of Coprates Chasma: A Study of Possible Emplacement Mechanisms
Authors: Buczkowski Debra L. , Seelos Kimberly D. , Viviano Christina E. , Murchie Scott L. , Seelos Frank P. , Malaret Erick , Hash Christopher 
Published: October 2019

AbstractThe formation of widespread phyllosilicate‐bearing near‐surface layers on Mars has often been attributed to pedogenesis, a process of weathering basaltic soils by continued exposure to meteoric water percolating down from the surface, which can result in layers of aluminum phyllosilicates forming over layers of iron‐magnesium phyllosilicates. We present evidence of an Fe/Mg‐smectite bearing layer stratigraphically above Al‐phyllosilicates in three circular features to the south of Coprates Chasma, suggesting that some process other than, or in addition to, a single pedogenic sequence must have been involved. A review of several formation mechanisms shows that all models require multiple episodes of aqueous alteration. In addition, only by invoking groundwater alteration in conjunction with pedogenesis can we reconcile the stratigraphic pattern of altered material exposed by these features.
Recovery of Soils From Acidic Deposition May Exacerbate Nitrogen Export From Forested Watersheds
Authors: Lawrence Gregory B. , Scanga Sara E. , Sabo Robert D. 
Published: October 2019

AbstractEffects of ambient decreases in N deposition on forest N cycling remain unclear as soils recover from acidic deposition. To investigate, repeated soil sampling data were related to deposition, vegetation, and stream data, for 2000–2015 in North and South Buck Creek watersheds, in the Adirondack region of New York, USA. In 63 other Adirondack streams, NO3− concentrations were also compared between 2004–2005 and 2014–2015, and a link between soil calcium and stream NO3− was investigated using data from 387 Adirondack streams that were sampled in either 2003–2005 or 2010–2011. No trends in N export or NO3− concentrations were observed in either Buck watershed despite a 45% decrease in N deposition, although South Buck N export was 2 to 3 times higher than in North Buck, where 48% of deposited N was accounted for by accumulation in the upper soil. In marked contrast, the upper profile in South Buck showed a net loss of N. Increased decomposition appeared likely in South Buck as those soils are adjusted to lower levels of acidifying S deposition, whereas decomposition increases in North Buck were likely suppressed by high levels of natural organic acidity. Stream NO3− concentrations in Buck watersheds bracketed regional results and were consistent with the regional streams that showed no overall change in NO3− concentrations between 2004 and 2014. A negative correlation observed between NO3− concentration and watershed buffering capacity expressed as the ratio of Ca2+ to SO42− also suggested that stream NO3− concentrations were elevated where soil Ca depletion had occurred.
Marked changes in diversity and relative activity of picoeukaryotes with depth in the world ocean
Authors: Giner Caterina R , Pernice Massimo C , Balagué Vanessa , Duarte Carlos M , Gasol Josep M , Logares Ramiro , Massana Ramon 
Published: October 2019

Abstract
Microbial eukaryotes are key components of the ocean plankton. Yet, our understanding of their community composition and activity in different water layers of the ocean is limited, particularly for picoeukaryotes (0.2–3 µm cell size). Here, we examined the picoeukaryotic communities inhabiting different vertical zones of the tropical and subtropical global ocean: surface, deep chlorophyll maximum, mesopelagic (including the deep scattering layer and oxygen minimum zones), and bathypelagic. Communities were analysed by high-tthroughput sequencing of the 18S rRNA gene (V4 region) as represented by DNA (community structure) and RNA (metabolism), followed by delineation of Operational Taxonomic Units (OTUs) at 99% similarity. We found a stratification of the picoeukaryotic communities along the water column, with assemblages corresponding to the sunlit and dark ocean. Specific taxonomic groups either increased (e.g., Chrysophyceae or Bicosoecida) or decreased (e.g., Dinoflagellata or MAST-3) in abundance with depth. We used the rRNA:rDNA ratio of each OTU as a proxy of metabolic activity. The highest relative activity was found in the mesopelagic layer for most taxonomic groups, and the lowest in the bathypelagic. Altogether, we characterize the change in community structure and metabolic activity of picoeukaryotes with depth in the global ocean, suggesting a hotspot of activity in the mesopelagic.
Optimisation electric field inverse solving algorithm for non‐destructive detection of voltage on transmission lines
Authors: Wang Ru , Tian Jin , Wu Fei , Zhang Zhenhua , Liu Haishan , Gong Li 
Published: October 2019

Electromagnetic field inverse calculation plays a crucial role in solving the problem arising from the design and non‐destructive testing of electromagnetic devices in engineering. In this study, an optimisation algorithm for electric field inverse calculation is proposed, which enables non‐destructive detection of voltage on overhead transmission lines, enhances the robustness of the algorithm and improves the accuracy of calculation. Firstly, 2D and 3D calculation models of electric field are established. A multimedium calculation model with the operating environment of transmission lines considered is proposed. Based on the multimedium calculation method, the calculation environment is categorised into soil, vegetation, geology, and other media, and the correctness of the optimisation method is verified by the finite‐element method‐based model. Secondly, in order to eliminate the measurement noise and electric field distortion to the electric field measurement data, a modified model based on Kalman filter is constructed. Both multimedium calculation method and Kalman filter are applied to the inverse calculation of electric field as an optimisation electric field inverse solving algorithm. Finally, the inverse optimisation method is applied to 220 kV transmission lines and practical 500 kV ultra‐high voltage transmission lines, respectively, to improve the accuracy and robustness of calculation.
Minimum phase bipolar converter for DC microgrid applications
Authors: Kumar Pawan , Singh Rajeev Kumar , Mahanty Ranjit 
Published: October 2019

This study proposes a minimum phase bipolar converter for dc microgrid applications, which is derived from the combination of and Sepic converters with some modifications in both of them in order to get a minimum phase system. In the proposed bipolar converter (PBC), the equivalent series resistance of transfer capacitors of both and Sepic converters is increased by adding resistances and introducing magnetic coupling between the filter inductors of the Sepic converter with a series RC network. These circuit modifications eliminate right half plane zero from the PBC and thereby make it a minimum phase, unlike the conventional –Sepic bipolar converter. Due to the minimum phase behaviour, the proposed converter can deliver high load current, achieves high bandwidth and facilitates simpler controller design in contrast to the conventional –Sepic bipolar converter. Detailed steady state and dynamic modelling of the PBC has been carried out in order to show its advantages. A 500 W laboratory prototype has been developed and implemented using field programmable gate array‐based system to verify the operation of the proposed converter.
Adaptive maintain power signature scheme for power over ethernet system
Authors: Li Yongyuan , Zhu Zhangming 
Published: October 2019

Power over Ethernet (PoE) technology has been widely used in networking market for its space‐saving, flexibility and low cost. As the PoE system needs to meet maintain power signature (MPS) requirements specified by the IEEE standard, it is important for powered device (PD) to draw a predetermined minimum current. If the PD current goes below the minimum current, the power sourcing equipment (PSE) assumes the PD has been disconnected and terminates operating voltage. If a fixed current is added to exceed the minimum current, a phenomenon of power wasting will be caused during standby or ultra‐low power mode. This study proposes an adaptive MPS scheme to achieve power‐saving and meet the MPS requirements. It consists of current comparator and MPS circuit to extract the periodic pulsed current for MPS requirements. The proposed scheme has been fabricated in 0.18 μm 100 V Bipolar‐CMOS‐DMOS process adding no extra pin and an area is 1.45 × 2.23 mm2. Test results show that the proposed interface sources a periodic pulsed current with a period of 318 ms and 25% duty cycle to tackle the issue of MPS absence in very low power condition.
Three‐dimensional rotatable omnidirectional MCR WPT systems
Authors: Li Wanlu , Wang Quandi , Wang Yingcong , Kang Jianwei 
Published: October 2019

Recently, Wi‐Fi wireless power transfer (WPT) has attracted increasing attention. In this study, a rotatable three‐dimensional (3D) transmitter (Tx) is first designed which only needs to be powered by a single source without current amplitude or phase control. Mutual inductance formulas of the Tx and a receiver (Rx) during the Tx's 3D rotation are derived based on Biot‐Savart law and rotating matrix, and the maximum coupling areas are obtained. A method of achieving equal coupling of Rxs with the Tx which simultaneously charges two Rxs is proposed. A real rotatable 3D Tx and an omnidirectional magnetically coupled resonant (MCR) WPT prototype are fabricated, and the theoretical analysis is verified by simulation and experiment. Experiment displays that the maximum or desired coupling of single or two Rxs in 3D space can be obtained by calculated rotation combinations. The maximum power transfer efficiency (PTE) of the system can reach 90.2% with the transmission distance of 1.5 times the radius of Tx. Finally, the PTE can be maintained at 73% with the transmission distance varying from 18 to 27 cm by a novel method. The proposed 3D technique could be applied to many fields including Wi‐Fi WPT home devices, remote sensing and some mechanical systems.
Distribution of intramuscular giant lipomas in the functional compartments of the forearm: a report of 12 cases
Authors: Capkin Sercan , Cavit Ali , Yilmaz Kutay , Kaleli Tufan 
Published: October 2019

Abstract
Purpose The aim of this study was to investigate the distribution of intramuscular giant lipomas in the functional compartments of the forearm and to compare their clinical, radiological and histopathological features with those reported in the current literature.
Methods The study included 12 patients who were surgically treated for intramuscular lipomas > 5 cm in size located in the forearm that had been confirmed histopathologically between April 2006 and March 2017. Data about the patients with respect to age, sex, affected side, localisation of the lipomas in the forearm functional compartments, size, histopathological features and recurrence were collected. According to the clinical complaints, direct radiography and magnetic resonance imaging were applied.
Results The average diameter was 6.5 cm (range: 5.5–9 cm). All lipomas had a well-defined border. All the patients presented with soft-tissue masses that were painless in seven patients. Five patients had nerve compression symptoms. When the lipomas were classified according to the functional compartments of the forearm, six of them were located in the superficial volar compartment, two in the deep volar compartment, two in the deep dorsal compartment and two in the lateral compartment. All lipomas were surgically removed by marginal excision. None had complications or recurrence at a mean of 6.5 years follow-up (range: 1–12 years) after surgery.
Conclusions Intramuscular lipoma is a relatively uncommon tumour, especially in the forearm. Because of the proximity to the neurovascular structures in the forearm, excision of lipomas should be performed with care and include wide incisions. Additionally, knowing the anatomical features of the compartment where the lipoma is localised in the forearm is important in planning surgery to enable easier dissection of the lipoma and lessen the risk of damage to adjacent neurovascular structures.
Level of evidence Level 4