bluuebunny/crossref_metadata_2025_split huggingface dataset:
The thermodynamic effect of atmospheric mass on early Earth's temperature
Authors: Chemke R. , Kaspi Y. , Halevy I. 
Published: October 2016

AbstractObservations suggest that Earth's early atmospheric mass differed from the present day. The effects of a different atmospheric mass on radiative forcing have been investigated in climate models of variable sophistication, but a mechanistic understanding of the thermodynamic component of the effect of atmospheric mass on early climate is missing. Using a 3‐D idealized global circulation model (GCM), we systematically examine the thermodynamic effect of atmospheric mass on near‐surface temperature. We find that higher atmospheric mass tends to increase the near‐surface temperature mostly due to an increase in the heat capacity of the atmosphere, which decreases the net radiative cooling effect in the lower layers of the atmosphere. Additionally, the vertical advection of heat by eddies decreases with increasing atmospheric mass, resulting in further near‐surface warming. As both net radiative cooling and vertical eddy heat fluxes are extratropical phenomena, higher atmospheric mass tends to flatten the meridional temperature gradient.
A model for stealth coronal mass ejections
Authors: Lynch B. J. , Masson S. , Li Y. , DeVore C. R. , Luhmann J. G. , Antiochos S. K. , Fisher G. H. 
Published: October 2016

AbstractStealth coronal mass ejections (CMEs) are events in which there are almost no observable signatures of the CME eruption in the low corona but often a well‐resolved slow flux rope CME observed in the coronagraph data. We present results from a three‐dimensional numerical magnetohydrodynamics (MHD) simulation of the 1–2 June 2008 slow streamer blowout CME that Robbrecht et al. (2009) called “the CME from nowhere.” We model the global coronal structure using a 1.4 MK isothermal solar wind and a low‐order potential field source surface representation of the Carrington Rotation 2070 magnetogram synoptic map. The bipolar streamer belt arcade is energized by simple shearing flows applied in the vicinity of the helmet streamer's polarity inversion line. The flows are large scale and impart a shear typical of that expected from the differential rotation. The slow expansion of the energized helmet streamer arcade results in the formation of a radial current sheet. The subsequent onset of expansion‐induced flare reconnection initiates the stealth CME while gradually releasing the stored magnetic energy. We present favorable comparisons between our simulation results and the multiviewpoint SOHO‐LASCO (Large Angle and Spectrometric Coronagraph) and STEREO‐SECCHI (Sun Earth Connection Coronal and Heliospheric Investigation) coronagraph observations of the preeruption streamer structure and the initiation and evolution of the stealth streamer blowout CME.
Discrete element modeling of indentation tests to investigate mechanisms of CO2‐related chemomechanical rock alteration
Authors: Sun Zhuang , Espinoza D. Nicolas , Balhoff Matthew T. 
Published: October 2016

AbstractDuring CO2 injection into geological formations, petrophysical and geomechanical properties of host formations can be altered due to mineral dissolution and precipitation. Field and laboratory results have shown that sandstone and siltstone can be altered by CO2‐water mixtures, but few quantitative studies have been performed to fully investigate underlying mechanisms. Based on the hypothesis that CO2‐water mixtures alter the integrity of rock structure by attacking cements rather than grains, we attempt to explain the degradation of cementation due to long‐term contact with CO2 and water and mechanisms for changes in rock mechanical properties. Many sandstones, including calcite‐cemented quartzitic sandstone, chlorite‐cemented quartzitic sandstone, and hematite‐cemented quartzitic sandstone, contain interparticle cements that are more readily affected by CO2‐water mixtures than grains. A model that couples the discrete element method and the bonded‐particle model is used to perform simulations of indentation tests on synthetic rocks with crystal and random packings. The model is verified against the analytical cavity expansion model and validated against laboratory indentation tests on Entrada sandstone with and without CO2 alteration. Sensitivity analysis is performed for cementation microscopic parameters including stiffness, size, axial, and shear strength. The simulation results indicate that the CO2‐related degradation of mechanical properties in bleached Entrada sandstone can be attributed to the reduction of cement size rather than cement strength. Our study indicates that it is possible to describe the CO2‐related rock alteration through particle‐scale mechanisms.
Air pressure effects on sea level changes during the twentieth century
Authors: Piecuch Christopher G. , Thompson Philip R. , Donohue Kathleen A. 
Published: October 2016

AbstractInterpretation of tide gauge data in terms sea level (η) and ocean dynamics requires estimates of air pressure (pa) to determine the ocean's isostatic response—the inverted barometer effect (
). Three gridded pa products (HadSLP2, NOAA‐20CRv2, and ERA‐20C) are used alongside meteorological station pa and tide gauge η records to evaluate the contribution of
to η changes over the twentieth century. Agreement between gridded products is better during more recent periods and over regions with good historical data coverage, whereas it is worse for earlier time periods or in ocean areas with poor observational data coverage. Comparison against station data reveals the presence of systematic errors in the gridded products, for example, such that uncertainties estimated through differencing the gridded products underestimate the true errors by roughly 40% on interannual and decadal time scales. Notwithstanding such correlated errors, gridded products are still useful for interpretation of tide gauge data. Removing gridded estimates of
from η records reduces spatial variance in centennial trends across tide gauges by 10–30%, formal errors in centennial trends from individual gauges by ∼5%, and the temporal variance in detrended records by 10–15% on average (depending on choice of gridded product). Results here advocate for making the
correction to tide gauge records in studies of ocean circulation and global η over long, multidecadal, and centennial time scales using an ensemble mean taken across several gridded
products.
Deriving global parameter estimates for the Noah land surface model using FLUXNET and machine learning
Authors: Chaney Nathaniel W. , Herman Jonathan D. , Ek Michael B. , Wood Eric F. 
Published: October 2016

AbstractWith their origins in numerical weather prediction and climate modeling, land surface models aim to accurately partition the surface energy balance. An overlooked challenge in these schemes is the role of model parameter uncertainty, particularly at unmonitored sites. This study provides global parameter estimates for the Noah land surface model using 85 eddy covariance sites in the global FLUXNET network. The at‐site parameters are first calibrated using a Latin Hypercube‐based ensemble of the most sensitive parameters, determined by the Sobol method, to be the minimum stomatal resistance (rs,min), the Zilitinkevich empirical constant (Czil), and the bare soil evaporation exponent (fxexp). Calibration leads to an increase in the mean Kling‐Gupta Efficiency performance metric from 0.54 to 0.71. These calibrated parameter sets are then related to local environmental characteristics using the Extra‐Trees machine learning algorithm. The fitted Extra‐Trees model is used to map the optimal parameter sets over the globe at a 5 km spatial resolution. The leave‐one‐out cross validation of the mapped parameters using the Noah land surface model suggests that there is the potential to skillfully relate calibrated model parameter sets to local environmental characteristics. The results demonstrate the potential to use FLUXNET to tune the parameterizations of surface fluxes in land surface models and to provide improved parameter estimates over the globe.
Multidecadal climate and seasonal snow conditions in Svalbard
Authors: van Pelt W. J. J. , Kohler J. , Liston G. E. , Hagen J. O. , Luks B. , Reijmer C. H. , Pohjola V. A. 
Published: October 2016

AbstractSvalbard climate is undergoing amplified change with respect to the global mean. Changing climate conditions directly affect the evolution of the seasonal snowpack, through its impact on accumulation, melt, and moisture exchange. We analyze long‐term trends and spatial patterns of seasonal snow conditions in Svalbard between 1961 and 2012. Downscaled regional climate model output is used to drive a snow modeling system (SnowModel), with coupled modules simulating the surface energy balance and snowpack evolution. The precipitation forcing is calibrated and validated against snow depth data on a set of glaciers around Svalbard. Climate trends reveal seasonally inhomogeneous warming and a weakly positive precipitation trend, with strongest changes in the north. In response to autumn warming the date of snow onset increased (2 days decade−1), whereas in spring/summer opposing effects cause a nonsignificant trend in the snow disappearance date. Maximum snow water equivalent (SWE) in winter/spring shows a modest increase (+0.01 meters water equivalent (mwe) decade−1), while the end‐of‐summer minimum snow area fraction declined strongly (from 48% to 36%). The equilibrium line altitude is highest in relatively dry inland regions, and time series show a clear positive trend (25 m decade−1) as a result of summer warming. Finally, rain‐on‐snow in the core winter season, affecting ground ice formation and limiting access of grazing animals to food supplies, peaks during specific years (1994, 1996, 2000, and 2012) and is found to be concentrated in the lower lying coastal regions in southwestern Svalbard.
Dihydro‐β‐agarofurans from the Australian Endemic Rainforest Plant Denhamia pittosporoides Inhibit Leucine Transport in Prostate Cancer Cells
Authors: Wibowo Mario , Wang Qian , Holst Jeff , White Jonathan M. , Hofmann Andreas , Davis Rohan A. 
Published: October 2016

AbstractTwo previously unknown dihydro‐β‐agarofuran sesquiterpenoids, denhaminol I (1) and denhaminol J (2), together with four related and known metabolites, 1α,2α,6β,15‐tetraacetoxy‐9α‐benzoyloxy‐8‐oxodihydro‐β‐agarofuran (3), wilforsinine F (4), 1α,2α,6β,8α,15‐pentaacetoxy‐9α‐benzoyloxydihydro‐β‐agarofuran (5), and 1α,2α,6β,15‐tetraacetoxy‐9β‐benzoyloxydihydro‐β‐agarofuran (6), were isolated from the leaves of an Australian rainforest plant, Denhamia pittosporoides. The structures of compounds 1 and 2 were determined by analysis of their 1D/2D NMR and MS data. The absolute configuration of compound 1 was established by single‐crystal X‐ray diffraction analysis. Compounds 1 and 4 were shown to inhibit leucine transport in the human prostate cancer cell line LNCaP, with IC50 values of 51.5 and 95.5 μm, respectively. Both compounds 1 and 4 were more potent than the l‐type amino acid transporter (LAT) family inhibitor 2‐aminobicyclo[2.2.1]‐heptane‐2‐carboxylic acid (BCH). This is the first report of dihydro‐β‐agarofurans from D. pittosporoides.
Wasserbasierte Redox‐Flow‐Batterie mit hoher Kapazität und Leistung: das TEMPTMA/MV‐System
Authors: Janoschka Tobias , Martin Norbert , Hager Martin D. , Schubert Ulrich S. 
Published: October 2016

AbstractRedox‐Flow‐Batterien (RFBs) sind geeignet, große Mengen elektrischer Energie zu speichern und somit die schwankende Stromproduktion erneuerbarer Energiequellen auszugleichen. Im Rahmen der Diskussion einer verbesserten Netzstabilität werden sie als Speicherlösung zur Ergänzung von Wind‐ und Solarparks gehandelt. Die Mehrheit der konventionellen RFB‐Konzepte basiert jedoch auf stark sauren Lösungen von Metallsalzen oder organischen Verbindungen mit relativ schlechten Leistungsdaten. Hier wird eine Batterie vorgestellt, die das gut lösliche N,N,N‐2,2,6,6‐Heptamethylpiperidinyloxy‐4‐ammoniumchlorid (TEMPTMA) und das Viologenderivat N,N′‐Dimethyl‐4,4‐bipyridiniumdichlorid (MV) in einer sicheren, wässrigen Lösung als redoxaktives Material einsetzt. Die RFB nutzt Elektrolytlösungen mit einer Kapazität von 54 Ah L−1, die bei einer Zellspannung von 1.4 V eine Energiedichte von 38 Wh L−1 ermöglichen. Mit Peak‐Stromdichten von bis zu 200 mA cm−2 ist das TEMPTMA/MV‐System ein geeigneter Kandidat für kompakt gebaute RFBs in Anwendungsbereichen, die eine hohe Kapazität und Leistung erfordern.
Asymmetric Induction by a Nitrogen 14N/15N Isotopomer in Conjunction with Asymmetric Autocatalysis
Authors: Matsumoto Arimasa , Ozaki Hanae , Harada Shunya , Tada Kyohei , Ayugase Tomohiro , Ozawa Hitomi , Kawasaki Tsuneomi , Soai Kenso 
Published: October 2016

AbstractChirality arising from isotope substitution, especially with atoms heavier than the hydrogen isotopes, is usually not considered a source of chirality in a chemical reaction. An N2,N2,N3,N3‐tetramethyl‐2,3‐butanediamine containing nitrogen (14N/15N) isotope chirality was synthesized and it was revealed that this isotopically chiral diamine compound acts as a chiral initiator for asymmetric autocatalysis.
An Aqueous Redox‐Flow Battery with High Capacity and Power: The TEMPTMA/MV System
Authors: Janoschka Tobias , Martin Norbert , Hager Martin D. , Schubert Ulrich S. 
Published: October 2016

AbstractRedox‐flow batteries (RFB) can easily store large amounts of electric energy and thereby mitigate the fluctuating output of renewable power plants. They are widely discussed as energy‐storage solutions for wind and solar farms to improve the stability of the electrical grid. Most common RFB concepts are based on strongly acidic metal‐salt solutions or poorly performing organics. Herein we present a battery which employs the highly soluble N,N,N‐2,2,6,6‐heptamethylpiperidinyl oxy‐4‐ammonium chloride (TEMPTMA) and the viologen derivative N,N′‐dimethyl‐4,4‐bipyridinium dichloride (MV) in a simple and safe aqueous solution as redox‐active materials. The resulting battery using these electrolyte solutions has capacities of 54 Ah L−1, giving a total energy density of 38 Wh L−1 at a cell voltage of 1.4 V. With peak current densities of up to 200 mA cm−2 the TEMPTMA/MV system is a suitable candidate for compact high‐capacity and high‐power applications.
Structural evolution and reactivity of coal chars during combustion in oxyfuel atmosphere
Authors: Fei Hua , Li Peisheng , Liu Yang , Li Yuanlin 
Published: October 2016

AbstractThe coal chars were characterized by laboratory scale fixed bed, thermogravimetric analysis, ultimate analysis, N2 isothermal adsorption/desorption method and Brunauer–Emmett–Teller method. The specific surface area of two coal chars obtained by Brunauer–Emmett–Teller method could be estimated with the help of random pore model. It showed that random pore model had good ability to depict coal char combustion in oxyfuel, and the higher temperature increased the combustion rate of coal char. Specific surface area followed a similar trend to the micropore, indicating that the specific surface area was mainly determined by the micropore, which increased at the initial stage because of a large number of micropore expansion and generation of new pores. Total pore volume showed a maximum at a carbon conversion range of 0.2–0.4. The activation energy (AE) of Jiaozuo anthracite chars varied between 72 and 85 kJ/mol during combustion, and the values of the AE range between 46 and 77 kJ/mol for YBC. At the carbon conversion of >40%, the AE of two coal chars displayed a linear relationship, which was probably attributed to the pore structure variations of coal chars during combustion in oxyfuel. Copyright © 2016 Curtin University of Technology and John Wiley & Sons, Ltd.
Structures and properties of low‐shrinkage polypropylene composites
Authors: Wu Li‐Ping , Kang Wu‐Li , Chen Yi , Zhang Xin , Lin Xiao‐Hong , Chen Li‐Ye , Gai Jing‐Gang 
Published: October 2016

ABSTRACTThe high shrinkage and the low impact strength severely limit the applications of the isotactic polypropylene (iPP). In this article, we studied the shrinkage, microstructure, and mechanical properties of the composites consisted of iPP, short glass fiber (GF), maleic anhydride grafted polypropylene (MPP), maleic anhydride grafted polypropylene/polyolefin elastomer (MPPPOE) or composite toughening agents (CTAs). The results show that the shrinkage of the composite with 40% GF reduces to 0.0754% (24 h) and 0.0893(48 h), respectively, under room temperature, which is far lower than the shrinkage [1.782% (24 h) and 1.821% (48 h)] of the pure iPP. For the composite of PP/GF/MPPPOE/CTAs (55/30/5/10), the tensile strength increases to 65.53 MPa (33.8 MPa for pure iPP), the tensile modulus is 1445 MPa which is 136% higher than pure iPP, and the izod impact strength reaches 22.72 kJ/m2 (only 5.28 kJ/m2 for pure iPP). Not only the scale stability of iPP is remarkably improved, but also the comprehensive mechanical properties are enhanced drastically. This work may generate potential opportunities for iPP in those applications demanding high scale stability. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44275.
Influences of hybrid carbon nanofillers on structures and electrical properties of sulfonated poly(1,3,4‐oxadiazole)‐based composite films
Authors: Lee Eunbin , Jeong Young Gyu 
Published: October 2016

ABSTRACTSulfonated poly(1,3,4‐oxadiazole) (sPOD)‐based composite films, including 10 wt % hybrid carbon nanofillers composed of different weight ratios of multiwalled carbon nanotube (MWCNT) and graphene sheets, were manufactured via an efficient ultrasonication‐assisted solution mixing and casting. Fourier transform infrared (FTIR) spectra of the composite films confirmed the existence of specific interactions between sPOD backbone and MWCNT or graphene sheet. Transmission electron microscopic (TEM) images of cross sections of the composite films showed that 2‐dimensional (2D) graphene sheets formed an anisotropically oriented structure in the sPOD matrix film, but they are randomly dispersed owing to the introduction of 1‐dimensional (1D) MWCNT. Accordingly, the electrical resistivity of the composite films decreased largely from ∼103 Ω cm to ∼101 Ω cm with the increment of the relative MWCNT content in hybrid carbon nanofillers due to the synergistic bridging effect. Thus, sPOD‐based composite films with 10 wt % hybrid carbon nanofillers exhibited high performance in electric heating by attaining rapid temperature responsiveness, high electric power efficiency, and stable maximum temperatures under given applied voltages. It was also revealed that the hybrid composite films were operationally stable over a long‐term stepwise electric heating experiment. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44499.
Pebax membrane for CO2/CH4 separation: Effects of various solvents on morphology and performance
Authors: Isanejad Mojgan , Azizi Navid , Mohammadi Toraj 
Published: October 2016

ABSTRACTIn this study, the effects of different solvents on the morphology and permeation of poly(ether‐block‐amide) (Pebax‐1657) membranes were investigated. Pebax membranes were fabricated via a solution casting method with five different solvents, that is, N,N‐dimethyl formamide (DMF), N,N‐dimethyl acetamide (DMAc), N‐methyl‐2‐pyrrolidone (NMP), formic acid, and a mixture of ethanol (EtOH) with water (H2O). Cross‐sectional scanning electron microscopy analysis of the membranes was performed to investigate the morphology of the prepared membranes. X‐ray diffraction and Fourier transform infrared analysis were also carried out to characterize the membranes. The interactions of the polymer and various solvents were evaluated with Hansen solubility parameters. Permeation experiments for CO2 and CH4 gases were performed to study the effects of the solvents on the permeation properties of the membranes. The solvent properties, such as the molar volume, boiling point, and solubility parameters, were investigated as were the membranes characteristics, such as the crystallinity, d‐spacing, and fractional free volume. The results obtained from the experiments show that the CO2 permeability for the membranes prepared with different solvents followed this order: NMP > DMF > Formic acid > DMAc > H2O/EtOH mixture. With increasing molar volume, the gas permeability increased for all of the membranes, except for DMAc, which showed a lower permeability because of its highly crystalline structure. DMF showed a higher CO2/CH4 ideal selectivity compared to the other membranes and, consequently, could be introduced as the best solvent from all aspects for the Pebax‐1657 membrane. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44531.
Performance Analysis of The Auxiliary‐Model‐Based Multi‐Innovation Stochastic Newton Recursive Algorithm for Dual‐Rate Systems
Authors: Cao Pengfei , Luo Xionglin 
Published: October 2016

AbstractThe stochastic Newton recursive algorithm is studied for dual‐rate system identification. Owing to a lack of intersample measurements, the single‐rate model cannot be identified directly. The auxiliary model technique is adopted to provide the intersample estimations to guarantee the recursion process continues. Intersample estimations have a great influence on the convergence of parameter estimations, and one‐step innovation may lead to a large fluctuation or even divergence during the recursion. In the meantime, the sample covariance matrix may appear singular. The recursive process would cease for these reasons. In order to guarantee the recursion process and to also improve estimation accuracy, multi‐innovation is utilized for correcting the parameter estimations. Combining the auxiliary model and multi‐innovation theory, the auxiliary‐model‐based multi‐innovation stochastic Newton recursive algorithm is proposed for time‐invariant dual‐rate systems. The consistency of this algorithm is analyzed in detail. The final simulations confirm the effectiveness of the proposed algorithm.
A cooperative waiting strategy based on elliptical areas for the Dynamic Pickup and Delivery Problem with Time Windows
Authors: Escuín David , Larrodé Emilio , Millán Carlos 
Published: October 2016

SummaryThe purpose of this paper to present a cooperative scheduling algorithm for solving the Dynamic Pickup and Delivery Problem with Time Windows (DPDPTW). The idea behind cooperative waiting strategies is to calculate simultaneously the waiting times for all nodes in the solution. Classical non‐cooperative scheduling algorithms perform the scheduling for each route independently of the scheduling of the other routes. We present the Cooperative Scheduling Problem (CSP) based on the elliptical areas generated by vehicles waiting at their nodes. The CSP is solved by means of a genetic algorithm and is evaluated by using a set of benchmarks based on real‐life data found in the literature. Initially, two waiting strategies are presented: Wait‐Early‐Time scheduling and Balanced‐Departure scheduling. Extensive empirical simulations have been carried out by analyzing the degree of dynamism and the average waiting time, a new concept defined to take into account the gap between the time windows of pickup and delivery nodes. Copyright © 2016 John Wiley & Sons, Ltd.