bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geostrophic and ageostrophic circulation of a shallow anticyclonic eddy off Cape Bojador
Authors: Ruiz Simón , Pelegrí Josep L. , Emelianov Mikhail , Pascual Ananda , Mason Evan 
Published: January 2014

AbstractA shallow mesoscale anticyclonic eddy, observed south of the Canary Islands with satellite altimetry, has been intensively studied with multiparametric sampling. Hydrographic data from a CTD installed on an undulating Nu‐shuttle platform reveal the presence of a mesoscale anticyclonic eddy of ∼125 km diameter. The difference in sea level anomaly (SLA) between the interior and the edge of the eddy, as determined from altimetry, is ∼15 cm, which compares well with the maximum dynamic height differences as inferred using a very shallow reference level (130 m). Further, the associated surface geostrophic velocities, of about 35 cm s−1 in the northeast and southwest edges of the eddy, are in good agreement with direct velocity measurements from the ship. Deep rosette‐CTD casts confirm that the structure is a shallow eddy extending no deeper than 250 m before the fusion with another anticyclone. The SLA‐tendency (temporal rate of change of sea surface height) indicates a clear northwestward migration during the two first weeks of November 2008. Applying an eddy SSH‐based tracker, the eddy's velocity propagation is estimated as 4 km d−1. Use of the QG‐Omega equation diagnoses maximum downward/upward velocities of about ±2 m d−1. The instability of the Canary coastal jet appears to be the mechanism responsible for the generation of the shallow anticyclonic eddy.
Large bipolar lightning discharge events in winter thunderstorms in Japan
Authors: Wu Ting , Yoshida Satoru , Ushio Tomoo , Kawasaki Zen , Takayanagi Yuji , Wang Daohong 
Published: January 2014

AbstractUsing a low‐frequency lightning location system comprising nine stations, we have observed and analyzed 374 large and bipolar electric field change waveforms that occurred during the winter of 2012–2013. Since the waveforms are different from those produced by any well‐studied lightning discharge processes, we refer to these source discharge events using a new name: large bipolar events (LBEs). LBEs can be characterized by the following features: (1) All have the same polarity as negative return stroke. (2) All exhibit a single bipolar pulse with a pulse width around 15 µs and similar positive and negative cycles. (3) All are located on the land along the Japan Sea coast, indicating they are probably associated with high grounded objects. (4) Most LBEs produce very large electric field changes that are even larger than that of positive and negative return strokes. (5) Most LBEs are temporally isolated within several milliseconds but are frequently followed by intracloud discharges after tens of milliseconds. (6) Most LBEs produce a single well‐distinguished ionospheric reflection pulse, and the time difference between LBE pulse and the corresponding reflection pulse can be used to calculate ionospheric reflection height. It is speculated that LBE is a type of powerful and transient lightning discharge event produced within a compact region of strong electric field formed when the negative charge layer in thunderclouds is very close to the top of a tall grounded object.
Evidence of sea ice source in aerosol sulfate loading and size distribution in the Canadian High Arctic from isotopic analysis
Authors: Seguin Alison Michelle , Norman Ann‐Lise , Barrie Leonard 
Published: January 2014

AbstractThe influence of frost flowers and seawater brine on ion chemistry in snow, snowpack, ice cores, and aerosols is detected when a lower sulfate to sodium ratio than in seawater is present in polar regions. This evidence can be masked when large amounts of non‐sea‐salt sulfate are present from other sources such as biogenic and anthropogenic sulfate. Frost flower δ34S values were measured for the first time in frost flower sulfates and did not differ significantly from the sea salt δ34S values of +21‰. A method using stable isotopes is introduced to determine the limit of contributions from sea salt and sea ice sources (including frost flowers and brine) on sulfate concentrations in aerosol samples from Alert, Canada. Knowledge of the range of values of δ34Snss and the SO4/Na ratio found in sea ice sources (i.e., frost flowers) is used to quantitatively constrain the contributions from frost flowers and sea salt in the Arctic aerosol mass during the onset of winter in 2007 and 2008, allowing for quantification of non‐sea‐salt sulfate amounts during times when frost flowers are present. Frost flower and/or brine influence was found predominantly in the coarse‐mode aerosols (>0.95 µm). This method to determine the contributions from sea salt and sea ice sources can be carried over to future studies with snow and ice cores.
The responses of cloudiness to the direct radiative effect of sulfate and carbonaceous aerosols
Authors: Kim Dongchul , Wang Chien , Ekman Annica M. L. , Barth Mary C. , Lee Dong‐In 
Published: January 2014

AbstractThis study investigates the responses of the direct radiative effect of light absorbing and scattering carbonaceous and sulfate aerosols on cloudiness and associated radiative fluxes using an interactive aerosol‐climate model coupled with a slab ocean model. We find that without including the impact of aerosols on cloud microphysics in the model (indirect effect), the direct radiative effect of aerosols alone can cause a change in cloud coverage and thus in cloud flux change which is consistent with several previous studies. More notably, our result indicates that the direct radiative effect of absorbing aerosols can cause changes in both low‐level and high‐level clouds with opposite signs. As a result, the global mean cloud radiation response to absorbing aerosols has a rather small value. The change of cloud solar radiative response (all‐sky effect minus clear‐sky effect) at the top of the atmosphere due to the existence of direct radiative effect of scattering, absorbing, and both types of aerosols is 0.72, 0.08, and 0.81 Wm−2, respectively, all are comparable in quantity to the current estimation of aerosol direct radiative forcing. The cloud response due to the longwave radiative effect is 0.09, 0.18, and 0.27 Wm−2, respectively. The global means of the radiative flux and cloud radiative responses appear to be linearly additive; however, this is definitely not the case for the zonal mean or at the regional scale.
Effects of 3‐D clouds on atmospheric transmission of solar radiation: Cloud type dependencies inferred from A‐train satellite data
Authors: Ham Seung‐Hee , Kato Seiji , Barker Howard W. , Rose Fred G. , Sun‐Mack Sunny 
Published: January 2014

AbstractThree‐dimensional (3‐D) effects on broadband shortwave top of atmosphere (TOA) nadir radiance, atmospheric absorption, and surface irradiance are examined using 3‐D cloud fields obtained from one hour's worth of A‐train satellite observations and one‐dimensional (1‐D) independent column approximation (ICA) and full 3‐D radiative transfer simulations. The 3‐D minus ICA differences in TOA nadir radiance multiplied by π, atmospheric absorption, and surface downwelling irradiance, denoted as πΔI, ΔA, and ΔT, respectively, are analyzed by cloud type. At the 1 km pixel scale, πΔI, ΔA, and ΔT exhibit poor spatial correlation. Once averaged with a moving window, however, better linear relationships among πΔI, ΔA, and ΔT emerge, especially for moving windows larger than 5 km and large θ0. While cloud properties and solar geometry are shown to influence the relationships amongst πΔI, ΔA, and ΔT, once they are separated by cloud type, their linear relationships become much stronger. This suggests that ICA biases in surface irradiance and atmospheric absorption can be approximated based on ICA biases in nadir radiance as a function of cloud type.
Arctic sea ice and atmospheric circulation under the GeoMIP G1 scenario
Authors: Moore John C. , Rinke Annette , Yu Xiaoyong , Ji Duoying , Cui Xuefeng , Li Yan , Alterskjær Kari , Kristjánsson Jón Egill , Muri Helene , Boucher Olivier , Huneeus Nicolas , Kravitz Ben , Robock Alan , Niemeier Ulrike , Schulz Michael , Tilmes Simone , Watanabe Shingo , Yang Shuting 
Published: January 2014

AbstractWe analyze simulated sea ice changes in eight different Earth System Models that have conducted experiment G1 of the Geoengineering Model Intercomparison Project (GeoMIP). The simulated response of balancing abrupt quadrupling of CO2 (abrupt4xCO2) with reduced shortwave radiation successfully moderates annually averaged Arctic temperature rise to about 1°C, with modest changes in seasonal sea ice cycle compared with the preindustrial control simulations (piControl). Changes in summer and autumn sea ice extent are spatially correlated with temperature patterns but much less in winter and spring seasons. However, there are changes of ±20% in sea ice concentration in all seasons, and these will induce changes in atmospheric circulation patterns. In summer and autumn, the models consistently simulate less sea ice relative to preindustrial simulations in the Beaufort, Chukchi, East Siberian, and Laptev Seas, and some models show increased sea ice in the Barents/Kara Seas region. Sea ice extent increases in the Greenland Sea, particularly in winter and spring and is to some extent associated with changed sea ice drift. Decreased sea ice cover in winter and spring in the Barents Sea is associated with increased cyclonic activity entering this area under G1. In comparison, the abrupt4xCO2 experiment shows almost total sea ice loss in September and strong correlation with regional temperatures in all seasons consistent with open ocean conditions. The tropospheric circulation displays a Pacific North America pattern‐like anomaly with negative phase in G1‐piControl and positive phase under abrupt4xCO2‐piControl.
Outcrops on lunar crater rims: Implications for rim construction mechanisms, ejecta volumes and excavation depths
Authors: Sharpton Virgil L. 
Published: January 2014

AbstractThe raised rims of impact craters consist of ejecta deposited onto structurally uplifted target rocks. Although it is commonly accepted that ejecta makes up 50–75% of the total rim height, no previous measurements on well‐preserved, naturally occurring impact craters exist. Relying on data from the Lunar Reconnaissance Orbiter, I report the first direct measurements of the rim‐forming constituents from 21 lunar craters ranging in diameter from 2.2 km to 45 km. Results show that the ejecta deposit accounts for no more than ~20% of rim relief, and structural uplift is the primary mechanism of rim development in both simple and complex craters. Thick, quasi‐horizontal outcrops of coherent bedrock indicate that this uplift is the result of subsurface injection of debris or melt into the surrounding target rocks. Crater growth, at least during the latest portion of the excavation stage, therefore, proceeds mainly through injection—rather than ejection—of material. These results suggest that ejecta volumes and excavation depths may be factors of 3 to 4 less than previously considered.
Spectral description of migrating bed forms and sediment transport
Authors: Guala Michele , Singh Arvind , BadHeartBull Nicholas , Foufoula‒Georgiou Efi 
Published: January 2014

AbstractThis paper considers the problem of spatiotemporal bed topography evolution and sediment transport estimation in rivers with migrating bed forms of different types and sizes, in statistical equilibrium conditions. Instead of resorting to bed form classification, we propose to evaluate the evolution of multiscale bed topography as the integral of unit contributions defined through a space‒time Fourier decomposition of bed elevations. Using joint 2‒D spectra in the frequency and wave number domain, a functional relationship between the length scales and the timescales in which migrating bed forms are decomposed is proposed and developed into a dimensionless expression for scale‒dependent convection velocities. This formulation highlights the violation of Taylor's hypothesis for migrating bed forms, confirming statistically that larger bed forms travel slower as compared to smaller bed forms. This phenomenological description leads to a spectral extension of the Simons et al. (1965) formula for sediment transport to incorporate a range of multiscale migrating features. Both the scaling of convection velocities and the spectral estimate of sediment transport rate were validated through extensive bed elevation data from laboratory experiments conducted at the St. Anthony Falls Laboratory, for a range of Froude numbers 0.2<Fr<0.5, under varying discharge and bed material composition.
Obesity and other risk factors: The National Survey of U.S. Long‐Haul Truck Driver Health and Injury
Authors: Sieber W. Karl , Robinson Cynthia F. , Birdsey Jan , Chen Guang X. , Hitchcock Edward M. , Lincoln Jennifer E. , Nakata Akinori , Sweeney Marie H. 
Published: January 2014

BackgroundDrivers of heavy and tractor‐trailer trucks accounted for 56% of all production and nonsupervisory employees in the truck transportation industry in 2011. There are limited data for illness and injury in long‐haul truck drivers, which prompted a targeted national survey.MethodsInterviewers collected data during 2010 from 1,670 long‐haul truck drivers at 32 truck stops across the 48 contiguous United States that were used to compute prevalence estimates for self‐reported health conditions and risk factors.ResultsObesity (69% vs. 31%, P < 0.01) and current smoking (51% vs. 19%, P < 0.01) were twice as prevalent in long‐haul truck drivers as in the 2010 U.S. adult working population. Sixty‐one percent reported having two or more of the risk factors: hypertension, obesity, smoking, high cholesterol, no physical activity, 6 or fewer hours of sleep per 24‐hr period.ConclusionSurvey findings suggest a need for targeted interventions and continued surveillance for long‐haul truck drivers. Am. J. Ind. Med. 57:615–626, 2014. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.
Modeling of the degradation kinetics of biodegradable scaffolds: The effects of the environmental conditions
Authors: Heljak Marcin K. , Swieszkowski Wojciech , Kurzydlowski Krzysztof Jan 
Published: January 2014

ABSTRACTThe rate of hydrolytic degradation of tissue‐engineered scaffolds made from bioresorbable polyesters is dependent on several factors. Some are related to the properties of the degrading polymeric material, but others are related to the geometry of the porous structure and the operating environment. It is well known that the rate of hydrolytic degradation of a given object, porous or nonporous, is lower when it is exposed to dynamic conditions, a flowing medium, than when it operates in static conditions. The most likely reason is the more efficient removal of the acidic degradation products from the vicinity of the polymeric material when it is operating in a flowing medium. In this article, we present a new phenomenological reaction–diffusion model of aliphatic polymer degradation. The model can be used to predict the significance of various factors in in vitro degradation tests, with particular reference to the flow of the degradation medium, and the frequency of medium replacement in the case of static conditions. The developed model was used to simulate the degradation of poly(dl‐lactide‐co‐glycolide) scaffolds with different porosities subjected to static and dynamic testing conditions. The results confirm that the porosity of the scaffold had a significant influence on the degradation rate. It was shown that the combination of dynamic conditions and high porosity effectively reduced the mass loss and molecular weight loss of the degrading polymer. However, the effect of changes in the velocity of the flowing medium had a negligible effect on the rate of degradation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40280.
Independent investigation on the influences of the processing conditions on the reclamation of crosslinked isoprene rubber after the impregnation of a reclaiming reagent
Authors: Shi Jinwei , Jiang Kuan , Zou Hua , Ding Linlin , Zhang Xiaodan , Li Xiaolin , Zhang Liqun , Ren Dongyun 
Published: January 2014

ABSTRACTIn this study, the reclamation of sulfur (S)‐cured isoprene rubber (IR) was investigated independently after the impregnation process of the reclaiming reagent diphenyl disulfide (DD) into the crosslinked IR matrix with supercritical carbon dioxide (scCO2) as the transmission medium. According to the mass uptake of DD into IR and scanning electron microscopy–energy‐dispersive X‐ray spectrometry measurements, DD was highly impregnated and homogeneously dispersed in the network under 12 MPa at 80°C for 11 h in scCO2. During the impregnation process, almost no reclaiming reaction occurred. Then, through three different reclaiming methods, a mechanochemical method, a chemical method with oxygen, and a chemical method without oxygen, the influences of the shear force, reclaiming atmosphere, reaction time, and amounts of reclaiming reagent on the reclamation with crosslinked IR with pre‐impregnated DD were independently investigated and compared with those of the reaction without pre‐impregnated DD. The sol fraction of the reclaimed rubber and molecular weight of the sol were measured. The results show that the reclaiming speed greatly depended on the amount of reclaiming reagent and that the reclaiming reaction was dramatically accelerated when the reclaiming reagents were pre‐impregnated into the crosslinked IR under the same processing conditions. This indicated that the impregnation time of the reclaiming reagent into the crosslinked network constituted a large proportion of the reclaiming time. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40298.
Mass production of carbon nanotube‐reinforced polyacrylonitrile fine composite fibers
Authors: Weng Baicheng , Xu Fenghua , Lozano Karen 
Published: January 2014

ABSTRACTA facile and large‐scale production method of polyacrylonitrile (PAN) fibers and carboxyl functionalized carbon nanotube reinforced PAN composite fibers was demonstrated by the use of Forcespinning® technology. The developed polymeric fibers and carbon nanotube‐reinforced composite fibers were subsequently carbonized to obtain carbon fiber systems. Analysis of the fiber diameter, homogeneity, alignment of carbon nanotube and bead formation was conducted with scanning electron microscopy. Thermogravimetric analysis, electrical, and mechanical characterization were also conducted. Raman and FTIR analyses of the developed fiber systems indicate interactions between carbon nanotubes and the carbonized PAN fibers through π–π stacking. The carbonized carbon nanotube‐reinforced PAN composite fibers possess promising applications in energy storage applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40302.
The effect of polyethylene crystallinity and polarity on thermal stability and controlled release of essential oils in antimicrobial films
Authors: Efrati Roni , Natan Michal , Pelah Avishay , Haberer Anina , Banin Ehud , Dotan Ana , Ophir Amos 
Published: January 2014

ABSTRACTAntimicrobial packaging can preserve and increase shelf life of free preservatives food products. Active materials present in the packaging material can migrate, in a controlled manner, to the food surface, avoiding bacterial and fungal proliferation and keeping the food product edible for longer periods of time. Essential oils (EO) are natural antimicrobial agents that can be released to the headspace with no direct contact between the package and the food. To minimize loses of EO during high heat melt processing, a three stages process was implemented and tested. Antimicrobial films were prepared by melt mixing a variety of polyethylene copolymers in the presence of organo‐modified montmorillonite nano clay (NC) and thymol, an EO present in oregano and thyme. A controlled EO desorption from films can be achieved by changing the polymer crystallinity and polarity. As the crystallinity increased, the thermal stability of the EO during the extrusion process improved. The addition of NC affects the structure and homogeneity of the crystals. The combination of high polymer crystallinity and chemical affinity between EO and NC increased the thermal stability of the EO during film processing, enabling to control the desorption rate. The effect of multilayer structure based on varied densities and polarities was also studied. Increasing the polarity of the outer layers in multilayered film reduced the EO desorption rate as a result of chemical interactions between the polymer and the EO. The final antimicrobial activity of the films was also found to be dependent on the EO partitioning. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40309.
Effect of the compatibilizer, on the engineering properties of TPV based on Hypalon® and PP prepared by dynamic vulcanization
Authors: Mandal Asis K. , Chakraborty Debabrata , Siddhanta Samir K. 
Published: January 2014

ABSTRACTElastomeric Chlorosulfonated polyethylene (Hypalon®) and thermoplastic Polypropylene (PP) based thermoplastic vulcanizates (TPVs) were prepared in presence of different doses of compatibilizer, maleic anhydride grafted PP (PP‐g‐MA) by employing dynamic vulcanization technique. The effect of incorporation in different proportions of compatibilizer on mechanical, spectral, morphological, thermal, and rheological properties of such TPVs was studied and the same were compared to that of virgin PP and amongst themselves. The mechanical analysis of the prepared TPVs exhibited significant improvements in stress at 25% modulus, ultimate tensile strength (UTS), and hardness values. FTIR studies revealed that a chemical interaction had taken place between Hypalon® and functionalized compatibilizer during the process of dynamic vulcanization which led to an enhancement of interfacial adhesion between them. The two‐phase morphologies were clearly observed by scanning electron microscopic studies. The Tg values of Hypalon® was modified in the TPVs as exhibited by differential scanning calorimetric studies. TGA studies indicated the increase in thermal stability of all TPVs with respect to the elastomeric Hypalon®. Rheological properties showed that the compatibilizer reduces the melt viscosity of TPVs and thus facilitates the processibility of such TPVs. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40312.
Orthogonal surface functionalization through bioactive vapor‐based polymer coatings
Authors: Deng Xiaopei , Lahann Joerg 
Published: January 2014

ABSTRACTReactive chemical vapor deposition (CVD) polymerization provides a substrate‐independent platform for effective functionalization of virtually any solid substrates, flat, or curved, even with complex geometries. This article reviews bioactive surface functionalization strategies based on CVD polymerization and highlights commonly used surface chemistries. These reactions include alkyne–azide “click” chemistry, reactions of active esters with amine, aldehydes/ketones with hydrazides and alkoxyamines, thiols with alkenes and alkynes and surface‐initiated atom transfer radical polymerization. The resulting biofunctional surface coatings can facilitate orthogonal immobilization of more than one type of ligand on a substrate. CVD polymer coatings with nanoscale thicknesses are widely applicable in biomedical applications and can be easily integrated into micro‐ and nanodevice fabrication. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40315.