bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Study of Parameters Affecting Atom Probe Tomography Specimen Survivability
Authors: Prosa Ty J. , Strennen Savanna , Olson David , Lawrence Dan , Larson David J. 
Published: November 2018

AbstractSpecimen survivability is a primary concern to those who utilize atom probe tomography (APT) for materials analysis. The state-of-the-art in understanding survivability might best be described as common-sense application of basic physics principles to describe failure mechanisms. For example, APT samples are placed under near-failure mechanical-stress conditions, so reduction in the force required to initiate field evaporation must provide for higher survivability—a common sense explanation of survivability. However, the interplay of various analytical conditions (or instrumentation) and how they influence survivability (e.g., decreasing the applied evaporation field improves survivability), and which factors have more impact than others has not been studied. In this paper, we report on the systematic analysis of a material composed of a silicon-dioxide layer surrounded on two sides by silicon. In total, 261 specimens were fabricated and analyzed under a variety of conditions to correlate statistically significant survivability trends with analysis conditions and other specimen characteristics. The primary result suggests that, while applied field/force plays an obvious role in survivability for this material, the applied field alone does not predict survivability trends for silicon/silicon-dioxide interfaces. The rate at which ions are extracted from the specimen (both in terms of ions-per-pulse and pulse-frequency) has similar importance.
Identification of stable genotypes and genotype by environment interaction for grain yield in sorghum (Sorghum bicolor L. Moench)
Authors: Hamidou Massaoudou , Souleymane Oumarou , Ba Malick N. , Danquah Eric Yirenkyi , Kapran Issoufou , Gracen Vernon , Ofori Kwadwo 
Published: November 2018

AbstractSorghum is a staple food crop in Niger and its production is constrained by sorghum midge and the use of low yielding, local sorghum varieties. To improve sorghum productivity, it is crucial to provide farmers with high yielding sorghum cultivars that are resistant to midge. We evaluated 282 genotypes in four environments of Niger Republic. Alpha (0.1) lattice with two replications was the experimental design. Genotype and genotype by environment (GGE) biplot analysis was used to study grain yield (GY) stability and G × E interactions. The results revealed that two distinct mega environments were present. Genotype L232 was the best genotype for GY in the first planting date at Konni and the first and second planting dates (PDs) at Maradi. Genotype L17 was the best for GY in the second PD at Konni. The second PD at Konni was the most discriminating environment while the first PD at Konni is suitable for selecting widely adapted genotypes for GY.
Compact D-CRLH resonator for low-pass filter with wide rejection band, high roll-off, and transmission zeros
Authors: Choudhary Dilip Kumar , Abdalla Mahmoud A. , Chaudhary Raghvendra Kumar 
Published: November 2018

AbstractA compact low-pass filter (LPF) with wide rejection band based on T-type circuit of an enhanced dual composite right-/left-handed (D-CRLH) resonator is presented in this paper. The resonator has only one cell with series and parallel tank circuit. The parallel LC tank circuit has been realized by an interdigital capacitor and one shorted finger, whereas its series LC tank circuit is realized by an air gap capacitance and a short circuit stub. The filter has wide rejection band bandwidth with three transmission zeros (TZs). The filter bandwidth and TZs frequencies are controlled by the D-CRLH element values. The results of the proposed filter demonstrate minimum insertion loss in passband, high roll-off rate, and good figure of merit. The measured results are in good agreement with the simulated results. The detailed filter design is discussed in terms of circuit modeling, dispersion analysis, and full-wave simulation. Finally, the filter size is compact (0.10 λg × 0.15 λg) at cut-off frequency.
Magnetic Anomalies in Extensional Detachments: The Xistral Tectonic Window of the Lugo Dome (NW Spain)
Authors: Martínez Catalán José R. , Ayarza Puy , Álvarez Lobato Fernando , Villalaín Juan José , Durán Oreja Manuela , Martín Paramio Manuel , Rodríguez Gómez Silvia 
Published: November 2018

AbstractThe Eastern Galicia Magnetic Anomaly (EGMA) is a conspicuous feature of the aeromagnetic map of Iberia, which structurally overlaps the Lugo and Sanabria domes, two spatially linked late Variscan extensional structures that delineate a segment of the Ibero‐Armorican Arc. In the northern part of the Lugo Dome, the Xistral Tectonic Window exposes a deep section of the continental crust, which includes several extensional detachments and associated shear zones. The aim is to check whether or not there is a correlation between the extensional process and the EGMA. A map of the magnetic anomaly of the Xistral Tectonic Window acquired on land improves the resolution of the aeromagnetic data and shows that the EGMA is actually composed by several shorter wavelength anomalies reaching amplitudes up to 1,214 nT. Their location in relation to outcropping rocks and structures, together with 2‐D modeling, shows a conspicuous link between the anomalies and the extensional detachments. On a larger scale, the EGMA forms the northern part of a largeanomaly occupying the core of the Central Iberian Arc. This anomaly can be related to extension caused by gravitational collapse of the thickened Variscan crust, implying that like the EGMA, local anomalies might reflect extensional structures, many of which may remain buried. Our study may shed light on the origin of magnetic anomalies in other gneiss domes as it shows that they can be related with the doming process instead of being inherited from older rocks presently outcropping at the core of the domes.
A Sequence of up to 11 Seismic Discontinuities Down to the Midmantle Beneath Southeast Asia
Authors: Wölbern Ingo , Rümpker Georg 
Published: November 2018

AbstractThe Earth's mantle exhibits a layered structure seismically characterized by sudden velocity changes or strong gradients. Several seismic boundaries have been identified in the mantle, and a large number of theoretical calculations and laboratory experiments have contributed to the debate on their origin. We analyze P‐to‐S converted phases generated at such interfaces to image the velocity structure within the sublithospheric mantle beneath Indonesia. Our study confirms the existence of various layer boundaries in the upper and lower mantle revealing up to 11 consecutive discontinuities down to ~1,700‐km depth. We detect Ps phases from the Lehmann and the X discontinuities originating at ~245 and ~294 km, respectively, followed by the top of a low‐velocity layer (LVL‐410) at ~368 km. The transition zone discontinuities are imaged at average depths of 408 and 665 km, respectively, which indicates the absence of significant temperature anomalies. In the midmantle we find vague indications for another interface at ~970‐km depth. At ~1,220 km a negative phase is observed followed by a sequence of converting structures of unknown origin at ~1,320, ~1,460, and ~1,500 km. We interpret these interfaces as compositional anomalies related to persisting fragments of subducted lithosphere. A further boundary is observed at ~1,700 km. Even though different causes exist to explain the observed seismic discontinuities including mineral phase transitions, partial melt, and chemical changes, most of them require additional mineral components. Thus, our findings provide clear evidence for significant compositional alteration of the mantle beneath Indonesia as a result of recurring subduction.
Earthquake Stress Drop in the Charlevoix Seismic Zone, Eastern Canada
Authors: Onwuemeka John , Liu Yajing , Harrington Rebecca M. 
Published: November 2018

AbstractStress drop scaling relations of earthquakes in intraplate seismic zones are less well constrained, partly due to less dense instrumentation and lower seismicity rate. Here we use new data to estimate the static stress drop values of earthquakes in the Charlevoix Seismic Zone in eastern Canada (MN < 4.5), June 2012 to July 2017. We first perform double‐difference relocation to obtain the hypocentral distribution of 518 events, which highlights a diffuse distribution within the Charlevoix Seismic Zone, probably related to the highly fractured crust by a Devonian meteorite impact. Using spectral ratios, we obtain stress drop values of 47 events ranging from ~2 to 200 MPa, typical of intraplate earthquakes, and observe an invariant stress drop scaling in the magnitude range Mw 2.2–3.8. Events within the impact structure have higher stress drops than those outside, which may indicate differences of fault maturity of the St. Lawrence paleorift system and the presence of a distributed fracture network.
Bar Code Events in the Juno‐UVS Data: Signature ∼10 MeV Electron Microbursts at Jupiter
Authors: Bonfond B. , Gladstone G. R. , Grodent D. , Gérard J.‐C. , Greathouse T. K. , Hue V. , Kammer J. A. , Versteeg M. H. , Davis M. W. , Becker H. N. , Radioti A. , Elliott S. S. , Imai M. , Paranicas C. P. , Bolton S. J. , Levin S. M. , Connerney J. E. P. 
Published: November 2018

AbstractOne of the most intriguing discoveries of Juno is the quasi‐systematic detection of upgoing electrons above the auroral regions. Here we discuss a by‐product of the most energetic component of this population: a contamination resembling bar codes in the Juno‐UVS images. This pattern is likely caused by bursts of ∼10 MeV electrons penetrating the instrument. These events are mostly detected when Juno's magnetic footprint is located poleward of the main emission relative to the magnetic pole. The signal is not periodic, but the bursts are typically 0.1–1 s apart. They are essentially detected when Juno‐UVS is oriented toward Jupiter, indicating that the signal is due to upgoing electrons. The event detections occur between 1 and 7 Jovian radii above the 1‐bar level, suggesting that the electron acceleration takes place close to Jupiter and is thus both strong and brief.
Wave‐Particle Interaction of Alfvén Waves in Jupiter's Magnetosphere: Auroral and Magnetospheric Particle Acceleration
Authors: Saur Joachim , Janser Sascha , Schreiner Anne , Clark George , Mauk Barry H. , Kollmann Peter , Ebert Robert W. , Allegrini Frederic , Szalay Jamey R. , Kotsiaros Stavros 
Published: November 2018

AbstractWe investigate spatial and temporal scales at which wave‐particle interaction of Alfvén waves occurs in Jupiter's magnetosphere. We consider electrons, protons, and oxygen ions and study the regions along magnetic flux tubes where the plasma is the densest, that is, the equatorial plasma sheet, and where the plasma is the most dilute, that is, above the ionosphere, where auroral particle acceleration is expected to occur. We find that within a dipole L‐shell of roughly 30, the electron inertial length scale in the auroral region is the dominating scale, suggesting that electron Landau damping of kinetic Alfvén waves can play an important role in converting field energy into auroral particle acceleration. This mechanism is consistent with the broadband bidirectional electron distributions frequently observed by Juno. Due to interchange‐driven mass transport in Jupiter's magnetosphere, its magnetosphere‐ionosphere coupling is expected to be mostly not in local force balance. This might be a key reason for the dominant role of Alfvénically driven stochastic acceleration compared to the less frequently occurring, locally forced‐balanced, and thus static mono‐energetic unidirectional acceleration. Outside of approximately L = 30, the ion gyroperiod is the dominating scale suggesting that ion cyclotron damping of heavy ions plays a major role in heating magnetospheric plasma. We also present properties of the dispersion relationship and the polarization relationships of kinetic Alfvén waves including the important effects from the relativistic correction due to the displacement current in Ampère's law.
Methane Production From Marine Gas Hydrate Deposits in Korea: Thermal‐Hydraulic‐Mechanical Simulation on Production Wellbore Stability
Authors: Kim A. R. , Kim J. T. , Cho G. C. , Lee J. Y. 
Published: November 2018

AbstractDuring methane production induced by depressurization, significant mechanical responses of hydrate‐bearing sediment (HBS) such as large volume contraction and subsidence can possibly be generated. Moreover, this phenomenon is further exacerbated by strength and stiffness reduction in the HBSs as hydrate dissociation advances. As a result, the highest compressive strength is concentrated in the vicinity of the production wellbore. Therefore, it is essential to address and evaluate the mechanical responses of HBSs and conduct a stability analysis of the production well during depressurization and hydrate dissociation to prevent the destruction of production facilities and consequent leakage of methane gas. In this study, a reservoir‐scale thermal‐hydraulic‐mechanical coupled simulation using FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions) was conducted to evaluate the mechanical responses of HBSs and the stability of a wellbore during methane production by depressurization at the Ulleung Basin. The structural design and mechanical properties including the dimensions of wellbore components and interface properties related to the interaction behavior between the sediment and wellbore were considered in the three‐dimensional model.
Impact of a Surface Ice Lid on the Optical Properties of Melt Ponds
Authors: Lu P. , Cao X. , Wang Q. , Leppäranta M. , Cheng B. , Li Z. 
Published: November 2018

AbstractTo investigate the influence of a surface ice lid on the optical properties of a melt pond, a radiative transfer model was employed that includes four plane‐parallel layers: an ice lid, a melt pond, the underlying ice, and the ocean beneath the ice. The thickness Hs and the scattering coefficient σs of the ice lid are altered. Variations in the spectral albedo αλ and transmittance Tλ due to Hs for a transparent ice lid are limited, and scattering in the ice lid has a pronounced impact on the albedo of melt ponds as well as the vertical distribution of spectral irradiance in ponded sea ice. The thickness of the ice lid determines the amount of solar energy absorbed. A 2‐cm‐thick ice lid can absorb 13% of the incident solar energy, half of the energy absorbed by a 30‐cm‐deep meltwater layer below the lid. This has an influence on the thermodynamics of melting sea ice. The color and spectral albedo of refreezing melt ponds depend on the value of the dimensionless number σs·Hs. Good agreement between field measurements and our model simulations is found. The number σs·Hs is confirmed to be a good index showing that the influence of an ice lid with σs·Hs < 0.5 is negligible. This criterion can be easily performed during field observations through visually judging whether the ice lid has significantly changed the color of liquid melt ponds or not.
Decadal Shifts in Wind Patterns Reduced Continental Outflow and Suppressed Ozone Trend in the 2010s in the Lower Troposphere Over Japan
Authors: Okamoto S. , Tanimoto H. , Hirota N. , Ikeda K. , Akimoto H. 
Published: November 2018

AbstractThe large increase in the springtime free tropospheric ozone over the western and eastern North Pacific over the last decades has been linked to the increase in anthropogenic emissions in China. However, the increasing trend at Mt. Happo, Japan, has been unexpectedly suppressed since 2008, by 5–10 ppbv. In this paper, we analyzed the tropospheric ozone records at Mt. Happo, along with the changes in climate and anthropogenic emissions. We revealed, based only on observational data, that the changes in climate pattern play an important role in controlling the decadal ozone trend. We found that the persistent La Niña‐like wind pattern during 2008–2013 reduced the export of polluted air masses from East Asia to the western Pacific, even though Chinese emissions continued to increase. On the other hand, an El Niño‐like wind pattern during 1992–1996 and enhanced storm track activity during 2000–2006 enhanced the export of polluted air masses from East Asia, contributing to the accelerated ozone trends. The climate modulations were identified in the O3 trends at the surface sites in western and central Japan and at a remote marine boundary layer site, Minamitorishima. Without this climatic effect driven by the persistent La Niña‐like wind pattern, the ozone trend would have been further upward over the North Pacific in the late 2000s to the early 2010s.
Southern California Coastal Response to the 2015–2016 El Niño
Authors: Young Adam P. , Flick Reinhard E. , Gallien Timu W. , Giddings Sarah N. , Guza R. T. , Harvey M. , Lenain Luc , Ludka B. C. , Melville W. Kendall , O'Reilly W. C. 
Published: November 2018

AbstractWidespread erosion associated with energetic waves of the strong 2015–2016 El Niño on the U.S. West Coast has been reported widely. However, Southern California was often sheltered from the northerly approach direction of the offshore waves. The few large swells that reached Southern California were not synchronous with the highest tides. Although west coast‐wide tidal anomalies were relatively large in 2015–2016, in Southern California, total water levels (sum of tides, anomalies, and wave superelevation) were lower than during the 1997–1998 Niño, and comparable to the 2009–2010 Niño. Airborne lidar surveys spanning 300 km of Southern California coast show the beach response varied from considerable erosion to accretion. On average, the shoreline moved landward 10 m, similar to the 2009–2010 El Niño. Some San Diego county beaches were narrower in the 1997–1998 El Niño than in 2015–2016, consistent with the higher erosion potential in 1997–1998. Beach retreat exceeded 80 m at a few locations. However, 27% of the shoreline accreted, often in pocket beaches, or near jetties. While adjacent beaches eroded, estuary mouths accreted slightly, and several estuaries remained or became closed during the study period. Only 12% of cliffs eroded (mostly at the base), and the average cliff face retreat was markedly less than historical values. Only two cliff‐top areas retreated significantly. Although some areas experienced significant change, the potential for coastal erosion and damage in Southern California was reduced compared to the 1997–1998 El Niño, because of low rainfall, a northerly swell approach, and relatively limited total high‐water levels.
Water Source Signatures in the Spatial and Seasonal Isotope Variation of Chinese Tap Waters
Authors: Wang Shengjie , Zhang Mingjun , Bowen Gabriel J. , Liu Xuemei , Du Mingxia , Chen Fenli , Qiu Xue , Wang Liwei , Che Yanjun , Zhao Guoyong 
Published: November 2018

AbstractDifferent water sources exploited for public use have different exposure to risks associated with climatic and environmental change. Isotope ratios of tap water have previously been studied as a potential tool to link public supply waters with water source characteristics at local to continental scales, providing information on the footprint of and potential risks associated with the water sources used. Work that combines intensive spatial and temporal sampling with independent water management data has been limited, however. In this study, an extensive observation network was established during 2014–2016 to provide monthly tap water sampling across China. We show that the spatial distribution of annual mean tap water isotope ratios is generally consistent with that of local precipitation across China. We identify seasonal correlation between tap water and precipitation isotope ratios in south China, where use of surface water is prevalent. In contrast, relatively invariant tap water isotope ratios elsewhere in China, which are not correlated with seasonal variation of precipitation isotope ratios, can be attributed to use of groundwater or water from river basins with longer storage times. The tap water isotope signatures identified here could be widely applied to characterize water supplies and associated sustainability challenges in different regions worldwide.
Effects of Fine‐Scale Surface Alterations on Tracer Retention in a Fractured Crystalline Rock From the Grimsel Test Site
Authors: Tachi Yukio , Ito Tsuyoshi , Akagi Yosuke , Satoh Hisao , Martin Andrew J. 
Published: November 2018

AbstractFine‐scale alterations found on fracture surfaces and between fracture surfaces and rock matrix are key uncertainties that need to be considered when developing solute transport models for fractured crystalline rocks. This paper presents a comprehensive approach developed for coupling laboratory tests, microscopic observations, and modeling in order to understand and quantify tracer transport processes occurring in natural fracture surfaces, using a single‐fractured granodiorite sample from the Grimsel Test Site, Switzerland. Laboratory tests including through‐diffusion, batch sorption, and flow‐through tests using five tracers with different retention properties indicated that tracer retention was consistently in the sequence of HDO or HTO (deuterated or tritiated water) ≈ Se < Cs < Ni < Eu and as well as showing the existence of a diffusion‐resistance layer near the fracture surface, cation excess, and anion exclusion effects for diffusion. Microscale heterogeneities around the fracture were clarified and quantified by coupling X‐ray computed tomography and electron probe microanalysis. A three‐layer model incorporating as much data as possible including weathered vermiculite, foliated mica, and undisturbed matrix layers, and their properties such as porosity, sorption, and diffusion parameters, obtained from laboratory diffusion tests and microscopic observations, provided a much better interpretation for breakthrough curves and concentration distributions near‐fracture surface of all tracers, measured in flow‐through tests, than either a one‐ or two‐layer model. Mechanistic understanding and detailed modeling considering the effects of fine‐scale surface alteration around a natural fracture should improve confidence for the safety assessment in fractured crystalline rocks.
If Precipitation Extremes Are Increasing, Why Aren't Floods?
Authors: Sharma Ashish , Wasko Conrad , Lettenmaier Dennis P. 
Published: November 2018

AbstractDespite evidence of increasing precipitation extremes, corresponding evidence for increases in flooding remains elusive. If anything, flood magnitudes are decreasing despite widespread claims by the climate community that if precipitation extremes increase, floods must also. In this commentary we suggest reasons why increases in extreme rainfall are not resulting in corresponding increases in flooding. Among the possible mechanisms responsible, we identify decreases in antecedent soil moisture, decreasing storm extent, and decreases in snowmelt. We argue that understanding the link between changes in precipitation and changes in flooding is a grand challenge for the hydrologic community and is deserving of increased attention.