bluuebunny/crossref_metadata_2025_split huggingface dataset:
Initial measurements of O‐ion and He‐ion decay rates observed from the Van Allen probes RBSPICE instrument
Authors: Gerrard Andrew , Lanzerotti Louis , Gkioulidou Matina , Mitchell Donald , Manweiler Jerry , Bortnik Jacob , Keika Kunihiro 
Published: October 2014

AbstractH‐ion (∼45 keV to ∼600 keV), He‐ion (∼65 keV to ∼520 keV), and O‐ion (∼140 keV to ∼1130 keV) integral flux measurements, from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft B, are reported. These abundance data form a cohesive picture of ring current ions during the first 9 months of measurements. Furthermore, the data presented herein are used to show injection characteristics via the He‐ion/H‐ion abundance ratio and the O‐ion/H‐ion abundance ratio. Of unique interest to ring current dynamics are the spatial‐temporal decay characteristics of the two injected populations. We observe that He‐ions decay more quickly at lower L shells, on the order of ∼0.8 day at L shells of 3–4, and decay more slowly with higher L shell, on the order of ∼1.7 days at L shells of 5–6. Conversely, O‐ions decay very rapidly (∼1.5 h) across all L shells. The He‐ion decay time are consistent with previously measured and calculated lifetimes associated with charge exchange. The O‐ion decay time is much faster than predicted and is attributed to the inclusion of higher‐energy (> 500 keV) O‐ions in our decay rate estimation. We note that these measurements demonstrate a compelling need for calculation of high‐energy O‐ion loss rates, which have not been adequately studied in the literature to date.
Peak scaling method to measure temperatures in the laser‐heated diamond anvil cell and application to the thermal conductivity of MgO
Authors: Rainey E. S. G. , Kavner A. 
Published: October 2014

AbstractWe test and characterize a new method to measure 2‐D radial temperature distributions in the laser‐heated diamond anvil cell using comparisons against real and synthetic data. We show that this method (1) incorporates an inexpensive and robust design for laser‐heated diamond cell temperature measurements, (2) yields precise measurements of radial temperature distributions of laser‐heated samples, and (3) can be used in conjunction with numerical models to measure the pressure and temperature dependence of thermal conductivity of materials. We apply the method to determine the high‐pressure, high‐temperature thermal conductivity of MgO.
Initial results of LF sensor network for lightning observation and characteristics of lightning emission in LF band
Authors: Yoshida Satoru , Wu Ting , Ushio Tomoo , Kusunoki Kenichi , Nakamura Yoshitaka 
Published: October 2014

AbstractWe have been developing an LF sensor network called Broadband Observation network for Lightning and Thunderstorm (BOLT), to image the structure of lightning discharges in 3D using time of arrival (TOA) technique. This paper documents initial results and characteristics of BOLT source locations for further understanding of LF radiation associated with lightning. Theoretical reduced Chi‐square distribution fitted to BOLT observation data indicates a root mean square (rms) timing error of about 200 ns for each sensor. Monte Carlo simulations of BOLT indicate that at an altitude of 5000 m the standard deviations for horizontal differences between a known source and a location that the BOLT algorithm produces are less than 200 m, and vertical differences are less than 400 m in most of the network. Furthermore, comparison of BOLT and VHF source locations arriving at the same site within 5 µs indicates that the average difference for elevation direction is 0.73° with a standard deviation of 3.64°, and that for the azimuth direction is 0.58° with a standard deviation of 1.98°. Lightning flash processes of intracloud (IC) and cloud‐to‐ground (CG) flashes, including preliminary breakdown pulses, negative leaders, breakdown in the negative charge region (NCR), and an attempted leader, are well imaged by BOLT. Normalized amplitudes in E‐field change waveform of BOLT sources associated with negative leaders and breakdown occurred in the NCR do not have significant difference, implying that most BOLT sources in the NCR might be associated with negative recoil leaders.
A climatological analysis of high‐precipitation events in Dronning Maud Land, Antarctica, and associated large‐scale atmospheric conditions
Authors: Welker Christoph , Martius Olivia , Froidevaux Paul , Reijmer Carleen H. , Fischer Hubertus 
Published: October 2014

AbstractThe link between high precipitation in Dronning Maud Land (DML), Antarctica, and the large‐scale atmospheric circulation is investigated using ERA‐Interim data for 1979–2009. High‐precipitation events are analyzed at Halvfarryggen situated in the coastal region of DML and at Kohnen Station located in its interior. This study further includes a comprehensive comparison of high precipitation in ERA‐Interim with precipitation data from the Antarctic Mesoscale Prediction System (AMPS) and snow accumulation measurements from automatic weather stations (AWSs), with the limitations of such a comparison being discussed. The ERA‐Interim and AMPS precipitation data agree very well. However, the correspondence between high precipitation in ERA‐Interim and high snow accumulation at the AWSs is relatively weak. High‐precipitation events at both Halvfarryggen and Kohnen are typically associated with amplified upper level waves. This large‐scale atmospheric flow pattern is preceded by the downstream development of a Rossby wave train from the eastern South Pacific several days before the precipitation event. At the surface, a cyclone located over the Weddell Sea is the main synoptic ingredient for high precipitation both at Halvfarryggen and at Kohnen. A blocking anticyclone downstream is not a requirement for high precipitation per se, but a larger share of blocking occurrences during the highest‐precipitation days in DML suggests that these blocks strengthen the vertically integrated water vapor transport (IVT) into DML. A strong link between high precipitation and the IVT perpendicular to the local orography suggests that IVT could be used as a “proxy” for high precipitation, in particular over DML's interior.
Modeling hydraulic redistribution and ecosystem response to droughts over the Amazon basin using Community Land Model 4.0 (CLM4)
Authors: Yan Binyan , Dickinson Robert E. 
Published: October 2014

AbstractHydraulic redistribution is the process of soil water transport through the low‐resistance pathway provided by plant roots. It has been observed in field studies and proposed to be one of the processes that enable the Amazon rainforest to resist periodical dry spells without experiencing water limitations. How and to what extent hydraulic redistribution may increase vegetation resistance to longer or more severe droughts than seasonal dryness have not been investigated yet, which is the focus of this study. The artificially prolonged drought produced by the rainfall exclusion experiment is used as an example of long drought, and the 2005 drought is used as a severe drought. The parameterization of hydraulic redistribution proposed by Ryel et al. (2002) was incorporated into the Community Land Model version 4 (CLM4). Three paired numerical experiments were conducted, one set using the default model (CTL) and the other using the model with considerations of hydraulic redistribution (HR). Results show that the vegetation response (including evapotranspiration, biomass, and leaf area index (LAI)) to dryness of all the three types is better captured with hydraulic redistribution incorporated. Plants are more resistant to dryness when hydraulic redistribution increases plant water availability and thus facilitates their growth. When a drought is long lasting, the vegetation response is delayed by hydraulic redistribution. Therefore, if a drought ends earlier than permanent damage is made, the magnitude of vegetation response will be lowered by this mechanism, i.e., the vegetation will be more resistant to dryness.
The intensification of northern component deepwater formation during the mid‐Pleistocene climate transition
Authors: Poirier Robert K. , Billups Katharina 
Published: October 2014

AbstractWe reconstruct mid‐Pleistocene (marine isotope stages (MISs) 13–18) deepwater hydrography at Ocean Drilling Program Site 1063 (4583 m water depth, subtropical North Atlantic) using benthic foraminiferal stable isotope records. These new records complete an ~900 kyr long stratigraphy spanning MISs 8–29 (~250–1030 Ka) when combined with previously published records from Site 1063. The results indicate a change in the circulation regime of the abyssal subtropical North Atlantic during MIS 17. Prior to MIS 17, no significant glacial or interglacial δ13C gradients are evident between Site 1063 and the deep South Atlantic. After MIS 17, interglacial intervals at Site 1063 are characterized by δ13C values that consistently approach those recorded in the deep North Atlantic. Comparing Site 1063 δ13C values to 26 additional published records throughout the entire Atlantic basin supports the idea that this δ13C increase is unique to the deep North Atlantic. After MIS 17, the basin‐wide influence of higher δ13C values suggests an increased relative flux of northern sourced bottom waters during interglacial periods. The timing of northern sourced water influence at Site 1063 is consistent with the timing of a shift in the orientation of the Arctic Front. Thus, this shift may signify a link between the northward penetration of relatively warm, saline surface waters into the Norwegian‐Greenland Seas stimulating deep convection. Our findings fit well with the model of Imbrie et al. (1993) for the importance of the Nordic heat pump in establishing strong 100 kyr cyclicity in late Pleistocene glacial cycles.
On the relevance of two‐dimensional models for radiation of statistical sources in stratified media
Authors: Epstein Ariel , Tessler Nir , Einziger Pinchas D. 
Published: October 2014

AbstractWe present analytical closed‐form expressions for the radiation patterns of 2‐D line sources and 3‐D point dipoles embedded in a general multilayered configuration. While the former are simplified model sources, used as a preliminary analytical step to reduce derivation complexity, the latter have been shown experimentally to reproduce the electromagnetic behavior of many elementary statistical sources. By decomposing the sources to current elements generating pure transverse electric (TE) or transverse magnetic (TM) polarized radiation, we arrive at a unified format for the radiation pattern expression for all sources considered. Analyzing the common 1‐D (characteristic) Green's function, we show that the normalized TE‐polarized emission of model 2‐D electric line sources reproduces exactly the measured TE‐polarized radiation of statistical (3‐D) dipoles with random in‐plane orientation; the connection between the TM‐polarized emission of the two species is discussed, and physical interpretation is provided via the unified expression. These results specify the precise relations between the 2‐D and 3‐D models, providing intuition as well as guidelines for proper usage of simplified 2‐D results for analysis of realistic 3‐D statistical configurations.
Cooking increases net energy gain from a lipid‐rich food
Authors: Groopman Emily E. , Carmody Rachel N. , Wrangham Richard W. 
Published: October 2014

ABSTRACTStarch, protein, and lipid are three major sources of calories in the human diet. The unique and universal human practice of cooking has been demonstrated to increase the energy gained from foods rich in starch or protein. Yet no studies have tested whether cooking has equivalent effects on the energy gained from lipid‐rich foods. Using mice as a model, we addressed this question by examining the impact of cooking on the energy gained from peanuts, a lipid‐rich oilseed, and compared this impact against that of nonthermal processing (blending). We found that cooking consistently increased the energy gained per calorie, whereas blending had no detectable energetic benefits. Assessment of fecal fat excretion showed increases in lipid digestibility when peanuts were cooked, and examination of diet microstructure revealed concomitant alterations to the integrity of cell walls and the oleosin layer of proteins that otherwise shield lipids from digestive lipases. Both effects were consistent with the greater energy gain observed with cooking. Our findings highlight the importance of cooking in increasing dietary energy returns for humans, both past and present. Am J Phys Anthropol 156:11–18, 2015 © 2014 Wiley Periodicals, Inc.
The timing of spheno‐occipital fusion in hominoids
Authors: Balolia Katharine L. 
Published: October 2014

ABSTRACTThe degree of spheno‐occipital fusion has been used to assign a relative age to dentally mature hominoid cranial specimens. However, a recent study of captive individuals (Poe: Am J Phys Anthropol 144 (2011) 162–165) concluded that fusion of the spheno‐occipital suture in great ape taxa is of little utility for aging dentally mature individuals. In this contribution, I use dentally mature samples of extant hominoid taxa (Homo sapiens, Pan troglodytes schweinfurthii, Gorilla gorilla gorilla, Pongo pygmaeus pygmaeus and Hylobates lar) to investigate a) the temporal relationship between spheno‐occipital fusion and dental maturity, b) whether there is an association between the degree of spheno‐occipital fusion and relative age, c) whether there are differences in relative timing of spheno‐occipital fusion between taxa, and d) whether there are sex differences in the relative timing of spheno‐occipital fusion. Results suggest that a) a substantial proportion of dentally mature wild‐shot chimpanzee, gorilla and orang‐utans have unfused or partially fused spheno‐occipital synchondoses, b) there is an association between the degree of spheno‐occipital fusion and age, c) there are interspecific differences in the timing of spheno‐occipital fusion, and d) there are significant sex differences in spheno‐occipital fusion in chimpanzees, orang‐utans and gibbons. Thus, contrary to previous work, degree of spheno‐occipital fusion is a potentially useful indicator of relative maturity, especially in great ape taxa. Am J Phys Anthropol 156:135–140, 2015. © 2014 Wiley Periodicals, Inc.
Steuerung einer Elektronentransferreaktion an einer Metalloberfläche durch Manipulation der Bewegung und Orientierung der Reaktanten
Authors: Bartels Nils , Krüger Bastian C. , Auerbach Daniel J. , Wodtke Alec M. , Schäfer Tim 
Published: October 2014

AbstractStößt ein NO‐Molekül mit der Oberfläche eines Gold‐Einkristalls, kann das Molekül Schwingungsenergie an die Oberfläche abgeben oder Energie in Form von Schwingungsenergie aufnehmen. Diese Energieübertragung erfolgt über einen Elektronentransferprozess. Durch die Entwicklung neuer Methoden im Bereich des optischen Pumpens und zur Orientierung von Molekülen können jetzt alle wichtigen Freiheitsgrade für diesen Elektronentransferprozess kontrolliert werden. Dadurch erhalten wir tiefen Einblick in die Funktionsweise der Elektronentransferreaktion und demonstrieren, wie diese beeinflusst werden kann. Es zeigt sich, dass die Wahrscheinlichkeit für einen Elektronentransfer mit zunehmender Translations‐ und Schwingungsenergie sowie mit geeigneter Orientierung ansteigt. Wenn die Schwingungsenergie allerdings sehr hoch ist, wird die Translationsenergie unwichtig, und auch die Orientierung in Bezug auf die Oberfläche verliert an Bedeutung. Das Zusammenspiel aller drei Kontrollparameter kann anhand einfacher Modellpotentiale verstanden werden.
Synthesis, Structure, and Properties of O6‐Corona[3]arene[3]tetrazines
Authors: Guo Qing‐Hui , Fu Zhan‐Da , Zhao Liang , Wang Mei‐Xiang 
Published: October 2014

AbstractO6‐Corona[3]arene[3]tetraazines, a new class of macrocyclic compounds, were synthesized efficiently in a one‐pot reaction from the nucleophilic aromatic substitution reaction between 1,4‐dihydroxybenzene derivatives and 3,6‐dichlorotetrazine in warm acetonitrile. In the crystalline structure, the resulting macrocycles adopt highly symmetric structures of a regular hexagonal cavity with all bridging oxygen atoms and tetrazine rings located on the same plane with phenylene units orthogonally orientated. The constitutional aromatic rings are able to rotate around the macrocyclic annulus, depending on the steric effect of the substituents and temperature, in solution. The electron‐deficient nature revealed by cyclic voltammetry, differential pulse voltammetry, and characteristic absorbances at a visible region show the O6‐corona[3]arene[3]tetrazines to be suitable macrocyclic receptors for electron‐rich guests.
Controlling an Electron‐Transfer Reaction at a Metal Surface by Manipulating Reactant Motion and Orientation
Authors: Bartels Nils , Krüger Bastian C. , Auerbach Daniel J. , Wodtke Alec M. , Schäfer Tim 
Published: October 2014

AbstractThe loss or gain of vibrational energy in collisions of an NO molecule with the surface of a gold single crystal proceeds by electron transfer. With the advent of new optical pumping and orientation methods, we can now control all molecular degrees of freedom important to this electron‐transfer‐mediated process, providing the most detailed look yet into the inner workings of an electron‐transfer reaction and showing how to control its outcome. We find the probability of electron transfer increases with increasing translational and vibrational energy as well as with proper orientation of the reactant. However, as the vibrational energy increases, translational excitation becomes unimportant and proper orientation becomes less critical. One can understand the interplay of all three control parameters from simple model potentials.
Numerical analysis of flow in a highly efficient flotation column
Authors: Gong Maoming , Li Chunshan , Li Zengxi 
Published: October 2014

AbstractFor the purpose of optimization by numerical analysis, a highly efficient flotation column named cyclonic‐static micro‐bubble flotation apparatus, which is widely used in mineral processing, was simulated with computational fluid dynamics to study the distributions of velocity magnitude, pathlines, turbulent intensity, and turbulent kinetic energy under different discretization schemes, turbulence models, and rotational speeds of pump. This simulation was based on the volume of fluid multiphase and multiple reference frame models. Spatial discretization scheme had an obvious effect on the velocity distribution in the column and revolving flotation sections, especially in the former. The introduction of a turbulence model changed the velocity distribution, the turbulence state, and the pathlines in the column and revolving flotation sections. Moreover, the standard, renormalization group (RNG), and realizable k‐epsilon turbulence models had numerous differences. Among these models, the RNG and realizable turbulence models had the most similar results. As the rotational speed of pump increased, velocity and turbulence field intensified. The flow field in the column flotation section differed from that in the revolving flotation section. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Processing–formulation–performance relationships of polypropylene/short flax fiber composites
Authors: Mihai Mihaela , Chapleau Nathalie , Denault Johanne 
Published: October 2014

ABSTRACTThis work is a comprehensive study of the effect of extrusion process parameters and formulation on the properties of polypropylene (PP)/short flax fiber composites. The parameters that were varied during the twin‐screw extrusion process were screw configuration, revolutions per minute (rpm), extrusion temperature, and flow rate. The effect of the feeding zone location of cellulosic fiber was also considered. This study investigates the effect of the formulation, cellulosic fiber content, the presence of a coupling agent, and of a reactive additive on composite performance. The composites were characterized in terms of morphology and microstructure, fiber length, rheological, thermal, and mechanical properties. Sensibility to humidity and recyclability were also considered. When compared with as‐received PP, the tensile strength of injection‐molded parts increased with cellulosic content by up to 40 vol %, and the tensile modulus increased 3.5 times when a combination of coupling and reactive agents was used. Exposed to controlled humidity of 50% during 1 year, these composites exhibited a very low level of humidity uptake around 0.85 wt %. The processability of these materials using a cast film line and the mechanical properties of extruded sheets are also presented. Furthermore, these materials demonstrate a good recyclability using injection molding by keeping the integrality of their mechanical properties after five reprocessing cycles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41528.
High performance synthetic paper used for color printing based on ultrahigh molecular weight polyethylene/SiO2by using TIPS method
Authors: He Wenqing , Cheng Dangdang , Du Juan , Luo Yan 
Published: October 2014

ABSTRACTThe production of traditional cellulose paper not only consumes lots of timber, but also brings about some environmental issues. Therefore, it is being increasingly replaced by synthetic paper. In this study, ultrahigh molecular weight polyethylene (UHMWPE)/SiO2synthetic paper with high application performance was prepared by the thermally induced phase separation method using mineral oil as diluent. The corresponding properties of synthetic paper, including surface morphology, overall porosity, tensile strength, thermal stability, acid and alkali resistance, whiteness, and inkjet print effect were investigated respectively. The results show that the overall porosity of UHMWPE/SiO2synthetic paper is above 45%, and the tensile strength exceeds 4.3 MPa. UHMWPE/SiO2synthetic paper also presents light weight, as well as good resistance to heat, acid and alkali. Meanwhile, the average whiteness of the samples is up to 91.8%. The sample K‐50, which contains 31.5 wt % SiO2, takes on the best print performance caused by its dense surface and higher SiO2content. It is indicated that UHMWPE/SiO2synthetic paper has good market prospects in the color printing. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41529.
The modification of lanthanum‐exchanged montmorillonite with anionic surfactants to enhance the thermal stability of polyvinyl chloride
Authors: Wang Haijiao , Wang Heyun , Chen Kai , Song Yanmei , Wei Zhong , Xue Mei 
Published: October 2014

ABSTRACTA series of thermally stable lanthanum organic montmorillonites (La‐OMMTs) were successfully prepared by modifying Na‐MMT with anionic surfactants and lanthanum chloride. Fourier transform infrared spectroscopy and X‐ray diffraction indicated that the anionic surfactants resided in the interlayer spaces and expanded the MMT basal spacing from 1.23 nm to 3.3 nm. Thermogravimetric and differential thermal analysis (TG/DTA) results showed that the intercalation of sodium dodecyl sulfonate into the lanthanum organic MMT resulted in its excellent thermal stability. The use of the La‐OMMT samples in polyvinyl chloride (PVC) resins was tested, and the TG/DTG results revealed that the three La‐OMMTs could significantly enhance the thermal stability of PVC. The modified La‐OMMT with the highest thermal stability is expected to be useful in polymer/layered silicate nanocomposites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41535.