bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substrate Integrated Multibeam Antennas
Authors: Cheng Yu J. 
Published: November 2016

AbstractThere is an increasing need for antennas with multiple beam capability to satisfy the growing demand for communication systems and multiple target radars. In the millimeter‐wave frequency band, the power budget is usually costly and difficult to satisfy the requirement for long‐distance and wide‐coverage applications. Therefore, high‐gain, high‐efficient multibeam antennas are necessary for millimeter‐wave systems to improve their performances. An antenna array scheme based on the passive beamforming network (BFN) is an efficient way to form multiple beams in different directions from the same aperture. Depending on simple circuitry and cheap cost, this type of multibeam antenna can be a substitution of passive, active, and digital phased arrays.The currently popular substrate integrated waveguide (SIW) techniques, also called as postwall waveguide or laminated waveguide, combine the best and complementary features of both planar transmission lines and nonplanar waveguides. Thus, it is found very appropriate to construct different high‐frequency circuits and antennas that have been validated by several successful examples.This article presents recent achievements in the development of microwave and millimeter‐wave substrate integrated beamforming networks (BFNs) incorporating both lens‐ and circuit‐based types. They include SIW Butler matrix, Blass matrix, Nolen matrix, Rotman lens, R‐KR lens, reflector lens, and multimode lens. Integrated with proper antennas, compact and on‐substrate multibeam antenna arrays are achieved with good performance. Such a series of SIW BFNs and multibeam antennas present excellent candidates for low‐cost and mass‐reproducible applications in space‐ and ground‐based integrated systems with multiple beam capability.
Tissue Engineering Biomaterials
Authors: Ma Peter X. , Eyster Thomas W. , Doleyres Yasmine 
Published: November 2016

AbstractTissue engineering has shown great promise in developing novel therapies for treating injured tissue and organ failure. Scaffolds play a pivotal role in tissue engineering. Biodegradable polymers are the primary choice of material for tissue engineering scaffolds, due to their numerous advantageous properties. In this article, the principles of tissue engineering are discussed in relation to polymer science and engineering. The most frequently used polymers in tissue engineering are briefly reviewed. These include synthetic and natural polymers commonly used in constructing both porous and hydrogel scaffolds. Their structure and critical properties in relation to scaffold function are discussed in depth, along with a detailed review of the important roles functionalized materials and controlled release play in tissue engineering. Important polymer processing techniques in the context of scaffold fabrication are also reviewed. These include the textile technologies, electrospinning, particulate‐leaching techniques, phase‐separation techniques, rapid prototyping, and other novel three‐dimensional (3D) fabrication techniques. In this update, the impact of pluripotent stem cells, conductive polymers, controlled drug release, 3D printing, and nanofibrous topology on tissue engineering are also discussed.
Combining snow, streamflow, and precipitation gauge observations to infer basin‐mean precipitation
Authors: Henn Brian , Clark Martyn P. , Kavetski Dmitri , McGurk Bruce , Painter Thomas H. , Lundquist Jessica D. 
Published: November 2016

AbstractPrecipitation data in mountain basins are typically sparse and subject to uncertainty due to difficulties in measurement and capturing spatial variability. Streamflow provides indirect information about basin‐mean precipitation, but inferring precipitation from streamflow requires assumptions about hydrologic model structure that influence precipitation amounts. In this study, we test the extent to which using both snow and streamflow observations reduces differences in inferred annual total precipitation, compared to inference from streamflow alone. The case study area is the upper Tuolumne River basin in the Sierra Nevada of California, where distributed and basin‐mean snow water equivalent (SWE) estimates have been made using LiDAR as part of the NASA Airborne Snow Observatory (ASO). To reconstruct basin‐mean SWE for years prior to the ASO campaign, we test for a robust relationship between SWE estimates from ASO and from snow courses and pillows, which have a longer record. Relative to ASO's distributed SWE observations, point SWE measurements in this part of the Sierra Nevada tend to overestimate SWE at a given elevation, but undersample high‐elevation areas. We then infer precipitation from snow and streamflow, obtained from multiple hydrologic model structures. When included in precipitation inference, snow data reduce by up to one third the standard deviations of the water year total precipitation between model structures and improve the consistency between structures in terms of the yearly variability in precipitation. We reiterate previous findings that multiple types of hydrologic data improve the consistency of modeled physical processes and help identify the most appropriate model structures.
Two black carbon pools transported by the Changjiang and Huanghe Rivers in China
Authors: Wang Xuchen , Xu Caili , Druffel Ellen M. , Xue Yuejun , Qi Yuanzhi 
Published: November 2016

AbstractMajor rivers play important roles in transporting large amounts of terrestrial organic matter from land to the ocean each year, and the organic matter carried by rivers contains a significant fraction of black carbon (BC). A recent study estimated that 0.027 Gt of BC is transported in the dissolved phase by rivers each year, which accounts for ~10% of the global flux of dissolved organic carbon. The relative sources of this large amount of riverine dissolved black carbon (DBC) from biomass burning (young, modern 14C) and fossil fuel (old, 14C free) combustion are not known. We present radiocarbon measurements of BC in both dissolved and particulate phases transported by the Changjiang and Huanghe Rivers, the two largest rivers in China, during 2015. We show that two, distinct BC pools (young and old) were carried by the rivers. The DBC pool was much younger than the particulate BC (PBC) pool. Mass balance calculations indicate that most (78–85%) of the DBC in the Changjiang and Huanghe Rivers was derived from biomass burning, and only 15–22% was from fossil fuel combustion. In contrast, PBC from biomass burning and fossil fuel combustion were approximately equal in these two rivers. Export of PBC and DBC by the rivers are decoupled, and fluxes of PBC were 4.1 and 6.7 times higher than DBC in the Changjiang and Huanghe Rivers, respectively. The 14C age differences of the two BC pools suggest that BC derived from biomass burning and fossil fuel combustion are mobilized in different phases and on different time scales in these rivers.
A practical tool for examining paleoerosion rates from sedimentary deposits using cosmogenic radionuclides: Examples from hypothetical scenarios and data
Authors: Val Pedro , Hoke Gregory D. 
Published: November 2016

AbstractWe provide a MatlabTM‐based algorithm that calculates paleoerosion rates based on measured Cosmogenic Radionuclide (CRN) concentrations from sedimentary deposits and additional geological constraints provided by the user. Based on the input data, the algorithm models CRN concentrations accumulated due to sediment burial and the subsequent exhumation of these deposits. Description of the methods and applications of the algorithm are provided, which includes single or coupled CRNs (i.e., 10Be or 10Be + 26Al). Results from the literature are reproduced. Further applicability of this algorithm is demonstrated with hypothetical scenarios of paleoerosion rates. The tool can be used toward the exploration of necessary assumptions, feasibility of case‐studies, and method limits. This contribution accompanies an overview of the paleoerosion rate method, its applications, and necessary assumptions.
Cryogenic flow features on Ceres: Implications for crater‐related cryovolcanism
Authors: Krohn K. , Jaumann R. , Stephan K. , Otto K. A. , Schmedemann N. , Wagner R. J. , Matz K.‐D. , Tosi F. , Zambon F. , von der Gathen I. , Schulzeck F. , Schröder S. E. , Buczkowski D. L. , Hiesinger H. , McSween H. Y. , Pieters C. M. , Preusker F. , Roatsch T. , Raymond C. A. , Russell C. T. , Williams D. A. 
Published: November 2016

AbstractCraters on Ceres, such as Haulani, Kupalo, Ikapati, and Occator show postimpact modification by the deposition of extended plains material with pits, multiple lobate flows, and widely dispersed deposits that form a diffuse veneer on the preexisting surface. Bright material units in these features have a negative spectral slope in the visible range, making it appear bluish with respect to the grey‐toned overall surface of Ceres. We calculate the drop height‐to‐runout length ratio of several flow features and obtain a coefficient of friction of < 0.1: The results imply higher flow efficiency for flow features on Ceres than for similar features on other planetary bodies with similar gravity, suggesting low‐viscosity material. The special association of flow features with impact craters could either point to an impact melt origin or to an exogenic triggering of cryovolcanic processes.
Work done by atmospheric winds on mesoscale ocean eddies
Authors: Xu Chi , Zhai Xiaoming , Shang Xiao‐Dong 
Published: November 2016

AbstractMesoscale eddies are ubiquitous in the ocean and dominate the ocean's kinetic energy. However, physical processes influencing ocean eddy energy remain poorly understood. Mesoscale ocean eddy‐wind interaction potentially provides an energy flux into or out of the eddy field, but its effect on ocean eddies has not yet been determined. Here we examine work done by atmospheric winds on more than 1,200,000 mesoscale eddies identified from satellite altimetry data and show that atmospheric winds significantly damp mesoscale ocean eddies, particularly in the energetic western boundary current regions and the Southern Ocean. Furthermore, the large‐scale wind stress curl is found to on average systematically inject kinetic energy into anticyclonic (cyclonic) eddies in the subtropical (subpolar) gyres while mechanically damps anticyclonic (cyclonic) eddies in the subpolar (subtropical) gyres.
First performance results of a new field‐widened spatial heterodyne spectrometer for geocoronal Hα research
Authors: Gardner D. D. , Mierkiewicz E. J. , Roesler F. L. , Harlander J. M. , Jaehnig K. P. , Nossal S. M. , Haffner L. M. 
Published: November 2016

AbstractA new, high‐resolution field‐widened spatial heterodyne spectrometer (FW‐SHS) designed to observe geocoronal Balmer α (Hα, 6563 Å) emission was installed at Pine Bluff Observatory (PBO) near Madison, Wisconsin. FW‐SHS observations were compared with an already well‐characterized dual‐etalon Fabry‐Perot Interferometer (PBO FPI) optimized for Hα, also at PBO. The FW‐SHS is a robust Fourier transform instrument that combines a large throughput advantage with high spectral resolution and a relatively long spectral baseline (~10 times that of the PBO FPI) in a compact, versatile instrument with no moving parts. Coincident Hα observations by FW‐SHS and PBO FPI were obtained over similar integration times, resolving powers (~67,000 and 80,000 at Hα) and fields of view (1.8° and 1.4°, respectively). First light FW‐SHS observations of Hα intensity and temperature (Doppler width) versus viewing geometry (shadow altitude) show excellent relative agreement with the geocoronal observations previously obtained at PBO by FPI. The FW‐SHS has a 640 km/s (14 Å) spectral band pass and is capable of determining geocoronal Hα Doppler shifts on the order of 100 m/s with a temporal resolution on the order of minutes. These characteristics make the FW‐SHS well suited for spectroscopic studies of relatively faint (~12–2 R), diffuse‐source geocoronal Hα emission from Earth's upper thermosphere and exosphere and the interstellar medium in our Galaxy. Current and future FW‐SHS observations extend long‐term geocoronal hydrogen observation data sets already spanning three solar minima. This paper describes the FW‐SHS first light performance and Hα observational results collected from observing nights across 2013 and 2014.
Identification of scintillation signatures on GPS signals originating from plasma structures detected with EISCAT incoherent scatter radar along the same line of sight
Authors: Forte Biagio , Coleman Chris , Skone Susan , Häggström Ingemar , Mitchell Cathryn , Da Dalt Federico , Panicciari Tommaso , Kinrade Joe , Bust Gary 
Published: November 2016

AbstractIonospheric scintillation originates from the scattering of electromagnetic waves through spatial gradients in the plasma density distribution, drifting across a given propagation direction. Ionospheric scintillation represents a disruptive manifestation of adverse space weather conditions through degradation of the reliability and continuity of satellite telecommunication and navigation systems and services (e.g., European Geostationary Navigation Overlay Service, EGNOS). The purpose of the experiment presented here was to determine the contribution of auroral ionization structures to GPS scintillation. European Incoherent Scatter (EISCAT) measurements were obtained along the same line of sight of a given GPS satellite observed from Tromso and followed by means of the EISCAT UHF radar to causally identify plasma structures that give rise to scintillation on the co‐aligned GPS radio link. Large‐scale structures associated with the poleward edge of the ionospheric trough, with auroral arcs in the nightside auroral oval and with particle precipitation at the onset of a substorm were indeed identified as responsible for enhanced phase scintillation at L band. For the first time it was observed that the observed large‐scale structures did not cascade into smaller‐scale structures, leading to enhanced phase scintillation without amplitude scintillation. More measurements and theory are necessary to understand the mechanism responsible for the inhibition of large‐scale to small‐scale energy cascade and to reproduce the observations. This aspect is fundamental to model the scattering of radio waves propagating through these ionization structures. New insights from this experiment allow a better characterization of the impact that space weather can have on satellite telecommunications and navigation services.
Partitioning of integrated energy fluxes in four tail reconnection events observed by Cluster
Authors: Tyler Evan , Cattell Cynthia , Thaller Scott , Wygant John , Gurgiolo Chris , Goldstein Melvyn , Mouikis Christopher 
Published: November 2016

AbstractWe present the partitioning of integrated energy flux from four tail reconnection events observed by Cluster, focusing on the relative contributions of Poynting flux, electron, H+ and O+ enthalpy, and kinetic energy flux in the tailward and earthward directions in order to study temporal and spatial features of each event. We further subdivide the Poynting flux into three frequency bands to examine the possible structures and waves that contribute most significantly to the total Poynting flux from the reconnection region. Our results indicate that H+ enthalpy flux is often dominant, but O+ enthalpy, electron enthalpy, Poynting flux, and H+ kinetic energy flux can contribute significant or greater total energy flux depending on spacecraft location with respect the current sheet, flow direction, temporal scale, and local conditions. We observe integrated H+ enthalpy fluxes that differ by factors of 3–4 between satellites, even over ion inertial length scales. We observe strong differences in behavior between H+ and O+ enthalpy fluxes in all events, highlighting the importance of species‐specific energization mechanisms. We find tailward‐earthward asymmetry in H+ enthalpy flux, possibly indicative of the influence of the closed earthward boundary of the magnetotail system. Frequency filtering of the Poynting flux shows that current sheet surface waves and structures on the timescale of current sheet flapping contribute significantly, while large‐scale structure contributions are relatively small. We observe that the direction and behavior of the Poynting flux differs between bands, indicating that the observed flux originates from multiple distinct sources or processes.
Three‐dimensional ionospheric tomography reconstruction using the model function approach in Tikhonov regularization
Authors: Wang Sicheng , Huang Sixun , Xiang Jie , Fang Hanxian , Feng Jian , Wang Yu 
Published: November 2016

AbstractIonospheric tomography is based on the observed slant total electron content (sTEC) along different satellite‐receiver rays to reconstruct the three‐dimensional electron density distributions. Due to incomplete measurements provided by the satellite‐receiver geometry, it is a typical ill‐posed problem, and how to overcome the ill‐posedness is still a crucial content of research. In this paper, Tikhonov regularization method is used and the model function approach is applied to determine the optimal regularization parameter. This algorithm not only balances the weights between sTEC observations and background electron density field but also converges globally and rapidly. The background error covariance is given by multiplying background model variance and location‐dependent spatial correlation, and the correlation model is developed by using sample statistics from an ensemble of the International Reference Ionosphere 2012 (IRI2012) model outputs. The Global Navigation Satellite System (GNSS) observations in China are used to present the reconstruction results, and measurements from two ionosondes are used to make independent validations. Both the test cases using artificial sTEC observations and actual GNSS sTEC measurements show that the regularization method can effectively improve the background model outputs.
Controlling factors of rainwater and water vapor isotopes at Bangalore, India: Constraints from observations in 2013 Indian monsoon
Authors: Rahul P. , Ghosh Prosenjit , Bhattacharya S. K. , Yoshimura Kei 
Published: November 2016

AbstractIsotopic ratios of rainwaters are believed to decrease with the amount of rainfall. However, analyses of the isotopic composition of rainwater and water vapor samples collected from Bangalore during the monsoon period of 2013 fail to show any simple relationship with the local meteorological parameters whereas show good correlation with the regional integrated convective activity. The correlation is particularly high when the averaging is done over the preceding 8 to 15 days, showing the influence of mixing or residence time scale of atmospheric moisture. This observation emphasizes the role of regional atmospheric circulation driving the isotopic values. A comparison between observed isotope ratios in water vapor and rainwater with Isotope‐enabled Global Spectral Model shows discrepancies between the two. The observed values are relatively enriched, indicating a systematic bias in the model values. The higher observed values suggest underestimation of the evaporation in the model, which we estimate to be about 28 ± 15% on average. Simultaneous analyses of rainwater and water vapor isotopic composition again show definitive presence of raindrop evaporation (31 ± 14%). We also documented a distinct pattern of isotopic variation in six samples collected at Bangalore due to mixing of vapor from a cyclonic system in close proximity that originated from the Bay of Bengal. It seems that large‐scale isotopic depletion occurs during cyclones caused by Rayleigh fractionation due to massive rainout. These results demonstrate the power of rainwater and water vapor isotope monitoring to elucidate the genesis and dynamics of water recycling within synoptic‐scale monsoon systems.
Reply to Comment by Xu et al. on “Sr‐Nd isotope composition and clay mineral assemblages in eolian dust from the central Philippine Sea over the last 600 kyr: Implications for the transport mechanism of Asian dust” by Seo et al.
Authors: Seo Inah , Lee Yong Il , Yoo Chan Min , Kim Hyung Jeek , Hyeong Kiseong 
Published: November 2016

AbstractAgainst Xu et al. (2016), who argued that East Asian Desert (EAD) dust that traveled on East Asian Winter Monsoon winds dominates over Central Asian Desert (CAD) dust in the Philippine Sea with presentation of additional data, we reconfirm Seo et al.'s (2014) conclusion that CAD dust carried on the Prevailing Westerlies and Trade Winds dominates over EAD dust in overall dust budget of the central Philippine Sea. The relative contribution of dust from EADs and CADs using clay mineral composition should be evaluated with elimination of mineralogical contribution from the volcanic end‐member which is enriched in kaolinite and overestimate the contribution of EAD dust.
Geodetic mass balance of surge‐type Black Rapids Glacier, Alaska, 1980–2001–2010, including role of rockslide deposition and earthquake displacement
Authors: Kienholz C. , Hock R. , Truffer M. , Arendt A. A. , Arko S. 
Published: November 2016

AbstractWe determine the geodetic mass balance of surge‐type Black Rapids Glacier, Alaska, for the time periods 1980–2001 and 2001–2010 by combining modern interferometric synthetic aperture radar (InSAR)‐derived digital elevation models (DEMs), DEMs derived from archival aerial imagery, laser altimetry data, and in situ surface elevation measurements. Our analysis accounts for both the large rockslides and terrain displacements caused by the 2002 M7.9 earthquake on the Denali fault, which runs through Black Rapids Glacier. To estimate uncertainties, we apply Monte Carlo simulations. For the earthquake‐triggered rockslides we find a volume of 56.62 ± 2.86 × 106 m3, equivalent to an average debris thickness of 4.44 ± 0.24 m across the 11.7 km2 deposit area on the glacier. Terrain displacement due to the earthquake corresponds to an apparent glacier volume change of −53.1 × 106 m3, which would cause an apparent specific mass balance of −0.19 meter water equivalent (mwe) if not taken into account. The geodetic mass balance of Black Rapids Glacier is −0.48 ± 0.07 mwe a−1 for the entire 30 year period, but more negative for the period 2001–2010 (−0.64 ± 0.11 mwe a−1) than the period 1980–2001 (−0.42 ± 0.11 mwe a−1), in agreement with trends indicated by in situ mass balance measurements. Elevation data indicate no net thickening of the surge reservoir between 1980 and 2010, in contrast to what is expected during the quiescent phase. A surge of Black Rapids Glacier in the near future is thus considered unlikely.