bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elevated gas flux and trace metal degassing from the 2014–2015 fissure eruption at the Bárðarbunga volcanic system, Iceland
Authors: Gauthier Pierre‐Jean , Sigmarsson Olgeir , Gouhier Mathieu , Haddadi Baptiste , Moune Séverine 
Published: February 2016

AbstractThe 2014 Bárðarbunga rifting event in Iceland resulted in a 6‐month long eruption at Holuhraun. This eruption was characterized by high lava discharge rate and significant gas emission. The SO2 flux for the first 3 months was measured with satellite sensors and the petrologic method. High‐resolution time series of the satellite data give 1200 kg/s that concurs with 1050 kg/s obtained from melt inclusion minus degassed lava sulfur contents scaled to the mass of magma produced. A high‐purity gas sample, with elevated S/Cl due to limited chlorine degassing, reveals a similar degassing pattern of trace metals as observed at Kīlauea (Hawai'i) and Erta Ale (Ethiopia). This suggests a common degassing mechanism at mantle plume‐related volcanoes. The trace metal fluxes, calculated from trace element to sulfur ratios in the gas sample and scaled to the sulfur dioxide flux, are 1–2 orders of magnitude stronger at Holuhraun than Kīlauea and Erta Ale. In contrast, volcanoes at convergent margins (Etna and Stromboli, Italy) have 1–2 orders of magnitude higher trace element fluxes, most likely caused by abundant chlorine degassing. This emphasizes the importance of metal degassing as chlorine species. Short‐lived disequilibria between radon daughters, 210Pb‐210Bi‐210Po measured in the gas, suggest degassing of a continuously replenished magma batch beneath the eruption site. Earlier and deep degassing phase of carbon dioxide and polonium is inferred from low (210Po/210Pb) in the gas, consistent with magma transfer rate of 0.75 m/s.
Enhanced MJO and transition to superrotation in warm climates
Authors: Carlson Henrik , Caballero Rodrigo 
Published: February 2016

AbstractUsing the NCAR CAM3 model in aquaplanet configuration, we perform a suite of simulations spanning a broad range of warm climates. The simulations show a spontaneous transition to superrotation, i.e., westerly winds at upper levels above the equator. The momentum convergence leading to superrotation is driven by eastward‐propagating equatorial waves with structure similar to the modern Madden‐Julian Oscillation (MJO), whose amplitude increases strongly with temperature. We analyze the moist static energy (MSE) budget of the model's MJO to identify mechanisms leading to its enhanced amplitude. Two such mechanisms are identified: a rapid increase of mean low‐level MSE with rising temperature, as found in previous work, and reduced damping of the MJO by synoptic‐scale eddies. Both effects imply a reduced gross moist stability and enhanced MJO amplitude. The reduced eddy damping is caused by the transition to superrotation, which allows a greater penetration of extratropical eddies into the equatorial zone; the dominant effect of this greater penetration is to flatten the meridional gradient zonal‐mean MSE, which effectively impedes the generation of anomalous MSE divergence by MJO‐modulated eddies. This mechanism implies a positive feedback between superrotation and the MJO which may hasten the transition into a strongly superrotating state.
Estimation of mesopause temperatures at low latitudes using the Kunming meteor radar
Authors: Yi Wen , Xue Xianghui , Chen Jinsong , Dou Xiankang , Chen Tingdi , Li Na 
Published: February 2016

AbstractIn this study, mesopause temperatures over a low‐latitude station were derived by applying the temperature gradient model technique to data from a meteor radar installation located in Kunming (25.6°N, 103.8°E), China. The estimated temperatures are in good agreement with Sounding of the Atmosphere by Broadband Emission Radiometry (SABER) temperatures and exhibit clear seasonal and interannual variations with dominant spectral peaks at annual, semiannual, quasi 90 day, and terannual oscillations. However, the amplitudes of the temperature fluctuations and the dominant spectral peaks are larger than those from SABER. An improved method that accounts for the temperature sensitivity of the slope estimated from the meteor radar data was developed to calibrate the larger fluctuations obtained using the temperature gradient model technique. The resulting calibrated temperatures are more consistent with SABER observations, and the accuracy of the derived temperatures is significantly improved.
Impact of scale/resolution on evapotranspiration from Landsat and MODIS images
Authors: Sharma Vivek , Kilic Ayse , Irmak Suat 
Published: February 2016

AbstractUnderstanding the role of landscape heterogeneity and its influence on the scaling behavior of surface fluxes as observed by satellite sensors with different spatial resolutions is a critical need to investigate. In this study, the effects of pixel scales on ETc estimation and other parameters that are used to calculate ETc were investigated over different vegetation surfaces in south central Nebraska, USA. Surface Energy Balance System (SEBS) was used to estimate spatially distributed ETc by combining ground‐based meteorological data for Landsat and MODIS imagery. The estimated surface energy fluxes were compared and validated to the measured Bowen Ratio Energy Balance System (BREBS) ETc fluxes. Validation results showed that Landsat has more preferable spatial resolution (30 m) to map and analyze ETc; regression models explained 91% of the variability in the observed data (RMSD = 0.064 mm/h; MBE = 0.04 mm/h). However, for MODIS‐based ETc, the regression model explained only 59% of the variability in observed ETc with a larger error (RMSD = 0.17 mm/h; MBE = 0.15 mm/h). MODIS‐based ETc was about 31% higher than the measured ETc. Imperfect assessment in MODIS‐based retrievals is due to the underlying assumption of spatial heterogeneity and coarser sensor pixel scale (500 m), which was summarized by up‐scaling the Landsat images to MODIS images using output flux aggregation and input up‐scaling procedure using simple average and nearest neighbor aggregation techniques and comparisons were made on both image and pixel scales. Aggregation results illustrate that simple average with output flux aggregation provides close interpretation in aggregating fluxes to coarser resolution than other aggregation approaches. Pixel‐by‐pixel comparison using output aggregation with simple average resulted in close agreement (error range 5%–35%) between measured and up‐scaled fluxes, compared to input up‐scaling using simple average (error range 25%–60%). Larger error in input up‐scaling is due to the changes in the surface roughness parameters due to aggregation in SEBS model. In addition, the magnitude of errors in ETc estimation was observed to be a function of the heterogeneity of the land surface and evaporative elements over the study region. Comparison between up‐scaled ETc at 480 m spatial resolution with original MODIS image at 500 m showed that the output aggregation using simple average aggregation method provided closer representation of ETc at 500 m MODIS pixel resolution than the nearest neighbor resampling method.
Market Design in the Smart Grid
Authors: Greve Thomas 
Published: February 2016

AbstractA successful market depends on the design and the mechanism used. However, first it needs to be asked – what is the market? How does it work? How does it fail? How can it be fixed when it is broken? One can pose the same questions in the area of electricity and smart grids. The goal is efficient trade. Efficient pricing and allocation are the ingredients necessary to achieve this goal. The right market design can answer the questions and can ensure the desired outcome. This chapter examines the possible transformation of design. It starts with an analysis of the market designs in use today, current changes in designs as a result of smart grids, and a potential market design for the future. Auctions are and have been the main market design mechanism in use. The focus therefore is on the necessary framework for using auctions. Further, it shows that the trend is moving away from the wholesale market toward the retail market to include active consumers with “smart” behavior. It suggests that there will be a move away from the use of capacity and energy markets and back toward an “energy‐only” market. These will have significant impacts on future electricity market design. Finally, this chapter presents a solution that could incorporate these future changes.
Impact on Electricity Markets
Authors: Green Richard , Webb Robert 
Published: February 2016

Abstract

This chapter seeks to explore the benefits and implications of the smart grid for electricity markets. The greater use of
ICT
(information and communication technologies) should allow consumers to receive more detailed and timely price signals, leading to more flexibility in the interaction between demand and supply. We review relevant literature and simulate the benefits of real‐time pricing in Great Britain, in the near future and in a mid‐century scenario with a large amount of electric heating and vehicle charging. The cost of providing energy could fall by around 10% if battery charging moves away from peak times and all consumers can respond to real‐time prices. There could be further savings in the provision of ancillary services if more consumers offer fast demand response as an alternative to keeping power stations part‐loaded for reserve. Dynamic pricing could solve the so‐called missing money problem of inadequate peak prices and allow energy‐only markets to fully reward‐generating capacity. New companies may be able to enter the industry with new business models, but we should be aware that the smart grid may create losers as well as winners and that the prospect of many small gains may not be enough to enthuse consumers.
Bottom hole pressure estimation and adaptive control in managed pressure drilling system
Authors: Li Zhiyuan , Hovakimyan Naira , Kaasa Glenn‐Ole 
Published: February 2016

SummaryIn the past decade, managed pressure drilling, a technology aiming at precise well pressure control, has been gaining increasing popularity and been a key enabler for some of the most challenging well drilling cases such as the offshore deep water well drilling. This paper attempts to solve two of the main challenges involved in the managed pressure drilling systems: first, the bottom‐hole states measurements are updated at a low rate, which can be practically viewed as unmeasured and thus need to be estimated in real time for both monitoring and control purposes and second, the drilling process is subject to uncertainties including unknown system parameters (e.g., frictions and densities), unmodeled actuator dynamics, and noise, which require a robust adaptive controller for control of the bottom‐hole pressure. Towards this objective, an integrated estimator and
adaptive control scheme is proposed. The estimator provides estimation of the bottom‐hole pressure and flow rate, based on the available measurements from the topside. The
adaptive controller drives the bottom‐hole pressure to the desired value following a reference model, which also handles the time delays in the input signal. The design is based on a recently developed nonlinear drilling model. The results demonstrate that the
adaptive controller has guaranteed performance bounds for both the input and the output signals of the system while using the estimation of the regulated outputs. Simulation results covering different operational conditions verify the theoretical findings. Copyright © 2016 John Wiley & Sons, Ltd.
Iridium‐ and Rhodium‐Catalyzed Carbocyclization between 2‐Phenylimidazo[1,2‐a]pyridine and α‐Diazo Esters
Authors: Li Yunyun , Wang Fen , Yu Songjie , Li Xingwei 
Published: February 2016

AbstractIridium(III) and rhodium(III) complexes can catalyze the carbocyclization between 2‐phenylimidazo[1,2‐a]pyridine and α‐diazo esters. The reaction occurs via CH activation and dialkylation of the arene followed by intramolecular nucleophilic substitution. Iridium(III) and rhodium(III) catalysis offer complementary scopes with respect to the α‐diazo esters.magnified image
Non‐Heme Imine‐Based Iron Complexes as Catalysts for Oxidative Processes
Authors: Olivo Giorgio , Lanzalunga Osvaldo , Di Stefano Stefano 
Published: February 2016

AbstractNon‐heme iron complexes are emerging as powerful and versatile catalysts in several oxidative transformations. The most investigated iron complex structures are based on aminopyridine ligands, but a number of imine‐based ligands have been also tested. In this review a collection of recent results obtained in oxidation catalysis with non‐heme imine‐based iron complexes is presented. Their catalytic performances in CH, CC and S oxidation are spread over a wide range of efficiency, going from very low to quite high. Such performances are discussed, whenever possible, in light of the operating reaction mechanisms and of catalyst stability. In order to facilitate the discussion, an initial survey of the most useful mechanistic tools widely applied to distinguish a metal‐based oxidation from a radical‐chain process is also reported. Imine‐based catalysts are divided into two classes: (i) salen‐Fe complexes, and (ii) imine‐Fe complexes. In some cases clues for free‐radical oxidation mechanisms have been reported while in other cases evidence for metal‐based mechanisms has been collected. The preferred mechanistic pathway is shown to be a function of catalyst structure and features. Interestingly, some imine‐based iron complexes are able to perform stereospecific oxidation reactions, demonstrating that the imine functionality can be incorporated in ligands designed for oxidation catalysis.magnified image
Spiro‐Pyrrolidine‐Catalyzed Asymmetric Conjugate Addition of Hydroxylamine to Enals and 2,4‐Dienals
Authors: Dou Qing‐Yun , Tu Yong‐Qiang , Zhang Ye , Tian Jin‐Miao , Zhang Fu‐Min , Wang Shao‐Hua 
Published: February 2016

AbstractA spiro‐pyrrolidine‐catalyzed tandem aza‐1,4‐addition/hemi‐acetalization reaction was developed with excellent enantioselectivity (12 examples of ≥99% ee), and several substrates proceeded with higher ee (up to 10% increase) compared with the literature data. Particularly, an interesting and unusual aza‐1,6‐/oxa‐1,4‐addition for some substrates was also observed.magnified image
Designing of Epoxy Matrix by Chemically Modified Multiwalled Carbon Nanotubes
Authors: Gantayat Subhra , Sarkar Niladri , Prusty Gyanaranjan , Rout Dibyaranjan , Swain Sarat K. 
Published: February 2016

ABSTRACTA chemical treatment was applied to functionalize multiwalled carbon nanotubes (MWCNTs) to introduce –COOH and –OH groups on the surface for better interfacial interaction with an epoxy matrix. The functionalized MWCNT (f‐MWCNT) reinforced epoxy nanocomposites were prepared with varying compositions up to 1 wt% MWCNTs. The interaction between MWCNTs and epoxy matrix was evidenced by Fourier transform infrared spectroscopy. The structure and microstructure of f‐MWCNTs reinforced epoxy composite were studied by X‐ray diffraction, field emission scanning electron microscope, high‐resolution transmission electron microscope, and Raman spectroscope. The orientation of f‐MWCNT was investigated by an atomic force microscope. The incorporation of f‐MWCNTs enhanced the thermal stability and the conductivity of the epoxy matrix significantly. The results of tensile strength, tensile strain, extension, and load at break clearly revealed a substantial improvement in tensile properties of the epoxy matrix due to homogeneous dispersion of f‐MWCNTs in the epoxy matrix and strong interfacial adhesion between them as well. The improvement in thermal and mechanical properties in combination with an increase in electrical properties may make the material suitable for making electronic devices.
Remarkable Charge Separation and Photocatalytic Efficiency Enhancement through Interconnection of TiO2 Nanoparticles by Hydrothermal Treatment
Authors: Ide Yusuke , Inami Nozomu , Hattori Hideya , Saito Kanji , Sohmiya Minoru , Tsunoji Nao , Komaguchi Kenji , Sano Tsuneji , Bando Yoshio , Golberg Dmitri , Sugahara Yoshiyuki 
Published: February 2016

AbstractAlthough tremendous effort has been directed to synthesizing advanced TiO2, it remains difficult to obtain TiO2 exhibiting a photocatalytic efficiency higher than that of P25, a benchmark photocatalyst. P25 is composed of anatase, rutile, and amorphous TiO2 particles, and photoexcited electron transfer and subsequent charge separation at the anatase–rutile particle interfaces explain its high photocatalytic efficiency. Herein, we report on a facile and rational hydrothermal treatment of P25 to selectively convert the amorphous component into crystalline TiO2, which is deposited between the original anatase and rutile particles to increase the particle interfaces and thus enhance charge separation. This process produces a new TiO2 exhibiting a considerably enhanced photocatalytic efficiency. This method of synthesizing this TiO2, inspired by a recently burgeoning zeolite design, promises to make TiO2 applications more feasible and effective.
Intercellular Connections Related to Cell–Cell Crosstalk Specifically Recognized by an Aptamer
Authors: Zhang Nan , Bing Tao , Shen Luyao , Song Rusheng , Wang Linlin , Liu Xiangjun , Liu Meirong , Li Juan , Tan Weihong , Shangguan Dihua 
Published: February 2016

AbstractIntercellular connections are an important pathway for cell–cell crosstalk. However, their formation mechanism and functions are far from being understood. The lack of molecular probes hampers the research in this area. Herein, we report a kind of intercellular connection that is specifically recognized by aptamer M17A2 generated by cell‐SELEX against MCF‐7R cells. These connections have different morphologies, but have the same skeleton composed of F‐actin. The long filamentous connections were identified to be tunneling nanotubes (TNTs), a recently discovered cell–cell communication route. These connections could be built not only between MCF‐7R cells, but also from MCF‐7R to other cells after co‐culture. Proteins could be transported between cells through these connections, suggesting their cell communication function. Aptamer M17A2 shows the potential to act as a new probe for investigating this kind of intercellular connection, as well as for studying cell–cell communication.
Iridium‐Catalyzed Enantioselective Indole Cyclization: Application to the Total Synthesis and Absolute Stereochemical Assignment of (−)‐Aspidophylline A
Authors: Jiang Shi‐Zhi , Zeng Xue‐Yi , Liang Xiao , Lei Ting , Wei Kun , Yang Yu‐Rong 
Published: February 2016

AbstractThe first enantioselective total synthesis of (−)‐aspidophylline A, including assignment of its absolute configuration has been accomplished. A key element of the synthesis is a highly enantioselective indole allylic alkylation/iminium cyclization cascade which was developed by employing a combination of Lewis acid activation and an iridium/ligand catalyst. This strategy relies on the direct use of 2,3‐disubstituted indoles with secondary allylic alcohols appended at C2 and heteronucleophiles appended at C3, indoles which are easily prepared from simple starting materials under C−H activation conditions.
Bimetallic Au2Cu6 Nanoclusters: Strong Luminescence Induced by the Aggregation of Copper(I) Complexes with Gold(0) Species
Authors: Kang Xi , Wang Shuxin , Song Yongbo , Jin Shan , Sun Guodong , Yu Haizhu , Zhu Manzhou 
Published: February 2016

AbstractThe concept of aggregation‐induced emission (AIE) has been exploited to render non‐luminescent CuISR complexes strongly luminescent. The CuISR complexes underwent controlled aggregation with Au0. Unlike previous AIE methods, our strategy does not require insoluble solutions or cations. X‐ray crystallography validated the structure of this highly fluorescent nanocluster: Six thiolated Cu atoms are aggregated by two Au atoms (Au2Cu6 nanoclusters). The quantum yield of this nanocluster is 11.7 %. DFT calculations imply that the fluorescence originates from ligand (aryl groups on the phosphine) to metal (CuI) charge transfer (LMCT). Furthermore, the aggregation is affected by the restriction of intramolecular rotation (RIR), and the high rigidity of the outer ligands enhances the fluorescence of the Au2Cu6 nanoclusters. This study thus presents a novel strategy for enhancing the luminescence of metal nanoclusters (by the aggregation of active metal complexes with inert metal atoms), and also provides fundamental insights into the controllable synthesis of highly luminescent metal nanoclusters.
Hydride Reduction by a Sodium Hydride–Iodide Composite
Authors: Too Pei Chui , Chan Guo Hao , Tnay Ya Lin , Hirao Hajime , Chiba Shunsuke 
Published: February 2016

AbstractSodium hydride (NaH) is widely used as a Brønsted base in chemical synthesis and reacts with various Brønsted acids, whereas it rarely behaves as a reducing reagent through delivery of the hydride to polar π electrophiles. This study presents a series of reduction reactions of nitriles, amides, and imines as enabled by NaH in the presence of LiI or NaI. This remarkably simple protocol endows NaH with unprecedented and unique hydride‐donor chemical reactivity.
A Strategy for Configuration of an Integrated Flexible Sulfur Cathode for High‐Performance Lithium–Sulfur Batteries
Authors: Wang Hongqiang , Zhang Wenchao , Liu Huakun , Guo Zaiping 
Published: February 2016

AbstractLithium–sulfur batteries are regarded as promising candidates for energy storage devices owing to their high theoretical energy density. The practical application is hindered, however, by low sulfur utilization and unsatisfactory capacity retention. Herein, we present a strategy for configuration of the sulfur cathode, which is composed of an integrated carbon/sulfur/carbon sandwich structure on polypropylene separator that is produced using the simple doctor‐blade technique. The integrated electrode exhibits excellent flexibility and high mechanical strength. The upper and bottom carbon layers of the sandwich‐structured electrode not only work as double current collectors, which effectively improve the conductivity of the electrode, but also serve as good barriers to suppress the diffusion of the polysulfide and buffer the volume expansion of the active materials, leading to suppression of the shuttle effect and low self‐discharge behavior.
Glycation Reactivity of a Quorum‐Sensing Signaling Molecule
Authors: Tsuchikama Kyoji , Gooyit Major , Harris Tyler L. , Zhu Jie , Globisch Daniel , Kaufmann Gunnar F. , Janda Kim D. 
Published: February 2016

AbstractReported herein is that (4S)‐4,5‐dihydroxy‐2,3‐pentanedione (DPD) can undergo a previously undocumented non‐enzymatic glycation reaction. Incubation of DPD with viral DNA or the antibiotic gramicidin S resulted in significant biochemical alterations. A protein‐labeling method was consequently developed that facilitated the identification of unrecognized glycation targets of DPD in a prokaryotic system. These results open new avenues toward tracking and understanding the fate and function of the elusive quorum‐sensing signaling molecule.