bluuebunny/crossref_metadata_2025_split huggingface dataset:
Energetics and geographic distribution of elve‐producing discharges
Authors: Chen Alfred Bing‐Chih , Su Han‐Tzong , Hsu Rue‐Ron 
Published: February 2014

AbstractThe major types of transient luminous events (TLEs) are believed to be directly triggered by cloud‐to‐ground discharges. Intense lightning generally seems to have a higher production efficiency for TLEs, but this observation has not yet been statistically investigated. Two data sets, the upgraded World Wide Lightning Location Network (WWLLN) lightning stroke data and the Imager of Sprites and Upper Atmospheric Lightning (ISUAL) TLE data, were used to investigate the energetics and the geographic distribution of TLE‐producing lightning. The global median energy of the strokes that produced the TLEs is at least an order of magnitude higher than the global median stroke energy for WWLLN lightning in the same data window. Furthermore, the energy distributions of the elve‐producing strokes exhibit no oceanic and land disparity. These results reveal that the elves are indeed triggered by energetic lightning and the production efficiency of elves with respect to the stroke energy of the causative lightning was insensitive to the underlying landform. Analysis of the spatial correlation between the ISUAL elves and the WWLLN lightning reveals that the geographic distribution of the ISUAL elves agreed well with that for the most energetic 10% of the WWLLN lightning strokes, better than for total lighting. We also found that elve occurrence rates in the apparently reduced detection regions behind the Earth's limb may have been greatly underestimated, partially due to the failure in providing triggers to initiate ISUAL recording or the severity of atmospheric attenuation to the elve emissions that may have caused them to be undetected.
Intensification and variability of the confluence of subtropical and subantarctic boundary currents east of New Zealand
Authors: Fernandez D. , Bowen M. , Carter L. 
Published: February 2014

AbstractThe confluence of subtropical and subantarctic boundary currents east of New Zealand creates strong fronts. The fronts have clear signatures in sea surface height (SSH) and sea surface temperature (SST) which make the confluence a good region to investigate the variability of the boundary currents of the South Pacific. Analysis of the 20 year time series of the SSH is used to investigate the location and strength of fronts, measured as the gradient in SSH (∇SSH), and the eddy kinetic energy (EKE) and their relationship to local and large‐scale wind forcing. The intensity of the ∇SSH and the EKE have increased at a rate of 0.02 cm km−1 and 32 cm2 s−2 decade−1, respectively. There is a significant correlation (r = 0.7, p < 0.01) between the ∇SSH and EKE signals, reflecting baroclinic instabilities inherent in the fronts. Differences between northward and southward wind‐driven transports across the confluence from the Island Rule are also increasing at 7.5 Sv decade−1 along with an upward trend in the SST differences across the region. Time series of the Southern Annular Mode (SAM) and Southern Oscillation Index (SOI) and local winds were compared to the frontal strength. Although the positive trend in the SOI coincides with increasing subtropical inflows, there is little correspondence of the indices and local winds with short‐term variability. While these results indicate a connection between the intensification of the confluence and South Pacific winds, there is little change in frontal location north of Bollons Seamount which suggests bathymetry influences the location of the confluence.
Eddies and an extreme water mass anomaly observed in the eastern south Pacific at the Stratus mooring
Authors: Stramma Lothar , Weller Robert A. , Czeschel Rena , Bigorre Sebastien 
Published: February 2014

AbstractIn the tropical eastern South Pacific the Stratus Ocean Reference Station (ORS) (∼20°S, 85.5°W) is located in the transition zone between the oxygen minimum zone (OMZ) and the well‐oxygenated subtropical gyre. In February/March 2012, extremely anomalous water mass properties were observed in the thermocline at the Stratus ORS. The available eddy oxygen anomaly was −10.5 × 1016 µmol. This anomalous water was contained in an anticyclonic mode‐water eddy crossing the mooring site. This eddy was absorbed at that time by an anticyclonic feature located south of the Stratus mooring. This was the largest water property anomaly observed at the mooring during the 13.5 month deployment period. The sea surface height anomaly (SSHA) of the strong mode‐water eddy in February/March 2012 was weak, and while the lowest and highest SSHA were related to weak eddies, SSHA is found not to be sufficient to specify the eddy strength for subsurface‐intensified eddies. Still, the anticyclonic eddy, and its related water mass characteristics, could be tracked backward in time in SSHA satellite data to a formation region in April 2011 off the Chilean coast. The resulting mean westward propagation velocity was 5.5 cm s−1. This extremely long‐lived eddy carried the water characteristics from the near‐coastal Chilean water to the open ocean. The water mass stayed isolated during the 11 month travel time due to high rotational speed of about 20 cm s−1 leading to almost zero oxygen in the subsurface layer of the anticyclonic mode‐water eddy with indications of high primary production just below the mixed layer.
Cyclogeostrophic balance in the Mozambique Channel
Authors: Penven Pierrick , Halo Issufo , Pous Stéphane , Marié Louis 
Published: February 2014

AbstractThree methods are proposed for the inclusion of inertia when deriving currents from sea surface height (SSH) in the Mozambique Channel: gradient wind, perturbation expansion, and an iterative method. They are tested in a model and applied to satellite altimetry. For an eddy of 25 cm amplitude and 100 km radius, typical of Mozambique Channel rings at 18°S, the error made with geostrophy is 40% for the anticyclones and 20% for the cyclones. Inertia could reach one third of the pressure gradient. Geostrophy underestimates subsurface currents by up to 50 cm s−1, resulting in errors of 30–40%. The iterative method results in errors of <5% for the most part of the structure. The error RMS in velocities based on 8 years of model SSH is in excess of 30 cm s−1 for geostrophy and reduces to about 10 cm s−1 for the gradient wind and iterative methods. The perturbation method is less accurate. Applied to satellite altimetry, the addition of inertia results in a significant increase in velocities for the anticyclones and a decrease for the cyclones. It induces a velocity increase of >50% in Mozambique Channel rings. Geostrophic EKE reaches 1400 cm2 s−2, while it attains 1800 cm2 s−2 when inertia is added. Applied to the Gulf Stream, these methods confirm the hypothesis of Maximenko and Niiler [2006] that centrifugal accelerations should be the main cause for the difference observed between geostrophic and drifter EKE. This methodology should result in a net improvement for operational surface ocean currents.
Dynamic mechanical properties of three‐component composites (acrylic polymer/epoxy/SiO2) in the glass‐transition region
Authors: Uematsu Hideyuki , Nishimoto Takashi , Tanoue Shuichi , Iemoto Yoshiyuki , Aoki Yuji , Sugimoto Masataka , Koyama Kiyohito 
Published: February 2014

ABSTRACTIn previous studies, we reported the linear and nonlinear rheological properties of three‐component composites consisting of acrylic polymer (AP), epoxy resin (EP), and various SiO2 contents (AP/EP/SiO2) in the molten state. In this study, the dynamic mechanical properties of AP/EP/SiO2 composites with different particle sizes (0.5 and 8 μm) were investigated in the glass‐transition region. The EP consisted of three kinds of EP components. The α relaxation due to the glass transition shifted to a higher temperature with an increase in the volume fraction (ϕ) for the AP/EP/SiO2 composites having a particle size of 0.5 μm, but the α relaxation scarcely shifted for the composite having a particle size of 8 μm as a general result. This result suggested that the SiO2 nanoparticles that were 0.5 μm in size adsorbed a lot of the low‐glass‐transition‐temperature (Tg) component because of their large surface area. The AP/SiO2 composites did not exhibit a shift in Tg; this indicated that the composite did not adsorb any component. The modulus in the glassy state (E′g) exhibited a very weak &phis; dependence for the AP/EP/SiO2 composites having particle sizes of 0.5 and 8 μm, although E′g of the AP/SiO2 composites increased with &phis;. The AP/EP/SiO2 composites exhibited a peculiar dynamic mechanical behavior, although the AP/SiO2 composites showed the behavior of general two‐component composites. Scanning electron microscopic observations indicated that some components in the EP were adsorbed on the surface of the SiO2 particles. We concluded that the peculiar behavior of the AP/EP/SiO2 composites was due to the selective adsorption of the EP component. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40409.
Structural, mechanical, thermal, and electrical properties of carbon black reinforced polyester resin composites
Authors: Alam M. K. , Islam M. T. , Mina M. F. , Gafur M. A. 
Published: February 2014

ABSTRACTCarbon black (CB) reinforced polyester resin (PR) composites (CPC) have been fabricated from mechanical mixtures of liquid PR and CB powder having 0–50 wt% CB contents and cured with 1% of methyl ethyl ketone peroxide at room temperature under a pressure of 50 MPa. The samples have been examined by the Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD) technique, scanning electron microscopy (SEM), mechanical test, micromechanical test, differential thermal analysis (DTA), and thermogravimetric analysis (TGA) and electrical test. FTIR spectra confirm the physical and chemical bond formations between CB and PR. XRD shows a very partial crystalline structure in cured PR and hexagonal structure in CB particles. SEM exhibits a clear dispersion of CB particles in PR matrix at lower loading and aggregates at higher loading. With the increase of fillers, while the tensile and flexural strengths of CPCs decrease, the Young's and tangent modulii increase by 80 and 100%, respectively. These increments are found consistent with the theoretical values. The degree of physical crosslinking between CB and PR as well as the aspect ratio of CB in CPCs are found to increase with the increase of filler. A remarkable increase in microhardness of about 61% at 50 wt% CB content is observed. The TGA represents that the thermal degradation temperature for pure PR is 373°C and that for CPC is 393°C. The dielectric constant of CPCs decreases with increasing frequency, whereas the ac‐ and dc‐ conductivities of CPC are found to increase with CB content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40421.
Novel fabrication route for porous silicon carbide ceramics through the combination of in situ polymerization and reaction bonding techniques
Authors: Ebrahimpour Omid , Esmaeili Babak , Griffon Lucie , Chaouki Jamal , Dubois Charles 
Published: February 2014

ABSTRACTFor the first time, an in situ polymerization technique was applied to produce mullite‐bonded porous SiC ceramics via a reaction bonding technique. In this study, SiC microsized particles and alumina nanopowders were successfully coated by polyethylene (PE), which was synthesized from the particle surface in a slurry phase reactor with a Ziegler–Natta catalyst system. The thermal studies of the resulting samples were performed with differential scanning calorimetry and thermogravimetric analysis. The morphology analysis obtained by transmission electron microscopy and scanning electron microscopy (SEM) confirmed that PE was successfully grafted onto the particle surface. Furthermore, the obtained porous ceramics were characterized in terms of their morphologies, phase composition, open porosity, pore size distribution, and mechanical strength. SEM observations and mercury porosimtery analysis revealed that the quality of the dispersion of nanosized alumina powder into the microsized SiC particles was strongly enhanced when the particles were coated by polymers with in situ polymerization. This resulted in a higher strength and porosity of the formed ceramic porous materials with respect to the traditional process. In addition, the X‐ray diffraction results reveal that the amount of mullite as the binder increased significantly for the samples fabricated by this novel method. The effects of the sintering temperature, forming pressure, and polymer content on the physical and mechanical properties of the final porous ceramic were also evaluated in this study. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40425.
Ultraviolet‐crosslinked hydrogel sustained‐release hydrophobic antibiotics with long‐term antibacterial activity and limited cytotoxicity
Authors: Liu Tao , Wu Ting , Liu Hongxi , Ke Bo , Huang Hongxing , Jiang Zhenyou , Xie Mingqiang 
Published: February 2014

ABSTRACTTo prolong erythromycin (EM) release and prevent the side effects of EM, a Pluronic F‐127 diacrylate macromer (PF127) was synthesized and then self‐assembled into micelles with their hydrophobic cores loaded with EM. The EM‐loaded micelles were mixed with a photoinitiator to form the EM/PF127 hydrogels rapidly under a low‐intensity UV light. Afterward, the hydrogel properties, antibacterial performance, and cytotoxicity of this novel hybrid hydrogel were investigated. The results show that the EM/PF127 hydrogel had a rapid gelation time. The sustained release of EM reduced its side effects. With controlled antibacterial activity, the use of EM would be safer and more efficient. What is more, the EM/PF127 hydrogel showed a slight cytotoxicity, and this suggests great potential application as antibacterial hydrogels in the prevention of postoperative infection. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40438.
Hybrid clay‐carbon nanotube/PET composites: Preparation, processing, and analysis of physical properties
Authors: Gorrasi Giuliana , D'Ambrosio Salvatore , Patimo Giovanni , Pantani Roberto 
Published: February 2014

ABSTRACTThe aim of this work was the preparation of novel composites of poly(ethylene terephthalate) (PET) and nano‐hybrid systems based on clay used as catalyst for the growth of multi walled carbon nanotubes (Clay‐CNTs), through catalytic chemical vapor deposition (CCVD). The carbon content into the hybrid filler was 58.1 wt %. Composites with 1.0, 1.5, 2.0, 3.0 wt % of Clay–CNTs were obtained by melt compounding and processed using a microinjection molding press. Unfilled PET was processed in the same composites conditions. Structural characterization and physical properties (thermal, degradation, mechanical, and electrical) were analyzed and correlated to the hybrid filler loading, and carbon nanotubes amount. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40441.
Effect of OMMTs on flame retardancy and thermal stability of poly(ethylene‐co‐vinyl acetate)/LDPE/magnesium hydroxide composites
Authors: Masoomi Mahmood , Bagheri Rouhollah , Ahmadkhanbeigi Leila , Asgari Mohammad 
Published: February 2014

ABSTRACTThe aim of this study was to prepare poly (ethylene‐co‐vinyl acetate) (EVA)/ low density polyethylene (LDPE)/magnesium hydroxide (MH) composites applicable in cable industry with required flame retardancy. For this reason, two types of organo‐modified montmorillonites (OMMT) with different surface polarites (Cloisite 15A and Cloisite 30B) at various concentrations, and also combination of these two OMMTs with overall loadings of 2 wt % and 5 wt % were used. The samples were compounded using a twin screw extruder with total (MH + OMMT) feeding of 55 wt % and 60 wt %. Limiting oxygen index (LOI) of the samples containing 2 wt % of OMMTs increased about 16% and dripping was suppressed according to vertical burning test (UL‐94V). Thermogravimetric results of EVA/LDPE/MH samples containing OMMT showed that the beginning of second step degradation was shifted about 50°C to higher temperatures. The composite tensile strength results showed enhancement by incorporating some amount of nanoclays with EVA/LDPE/MH composites. Scanning electron microscopy images confirmed that MH particles had better wetting by EVA matrix in presence of nanoclays. Oxidative induction time of the EVA/LDPE/MH/OMMT nanocomposites was 140 min, which was more than that of the samples without OMMT (20 min). Employing the equal weight ratios of the two OMMTs demonstrated a synergistic effect on flame retardancy of the samples according to the both tests results (LOI, UL‐94V). X‐ray diffraction analysis of the samples confirmed the intercalation/semiexfoliation structure of nanosilicate layers in the bulk of EVA/LDPE matrix. This led to longer elongation at break and thermal stability of Cloisite 15A based nanocomposites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40452.
Quinone propionic acid‐based redox‐triggered polymer nanoparticles for drug delivery: Computational analysis and in vitro evaluation
Authors: Bae Jungeun , Nael Manal A. , Jiang Lingzhou , Hwang Patrick TaeJoon , Mahdi Fakhri , Jun Ho‐Wook , Elshamy Wael M. , Zhou Yu‐Dong , Murthy S. Narasimha , Doerksen Robert J. , Jo Seongbong 
Published: February 2014

ABSTRACTRedox‐responsive polymers with pendant quinone propionic acid groups as a redox trigger were optimized by computational modeling to prepare efficient redox‐triggered polymer nanoparticles (NPs) for drug delivery. Lipophilicities at complete reduction of redox‐responsive polymers (<5000 Da) constructed with adipic acid and glutaric acid were remarkably reduced to range from −6.29 to −0.39 compared with nonreduced state (18.87–32.46), suggesting substantial polymer solubility reversal in water. Based on this hypothesis, redox‐responsive NPs were prepared from the synthesized polymers with paclitaxel as model cancer drug. The average size of paclitaxel‐loaded NPs was 249.8 nm and their reconstitutions were stable over eight weeks. In vitro drug release profiles demonstrated the NPs to release >80% of paclitaxel over 24 h at a simulated redox‐state compared with 26.5 to 41.2% release from the control. Cell viability studies revealed that the polymer was nontoxic and the NPs could release paclitaxel to suppress breast cancer cell growth. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40461.
Preparation technique and property evaluation of flame‐retarding/thermal‐insulating/puncture‐resisting PU foam composites
Authors: Li Ting‐Ting , Lou Ching‐Wen , Hsu Ying‐Hsuan , Lin Jia‐Horng 
Published: February 2014

ABSTRACTIn this study, flame‐retarding property of PU foam was realized by compounding with flame‐retarding nonwovens in order to stop flame burning and spread. Followed with global warming, thermal‐insulating materials are also used inside of building for energy conservation. This article presents preparation technique and property evaluation of PU composite board composed of composite nonwovens and PU foam by integrating foaming process. By optimization of composite nonwoven, effects of foam density and nonwoven composition on flame‐retarding and thermal‐insulating properties were discussed. Puncture resistance property of composite board was also investigated for resisting against sharp‐object impacts. The resultant composite board would be applied as partition materials in future building decoration. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40463.
Damping mechanism and different modes of molecular motion through the glass transition of chlorinated butyl rubber and petroleum resin blends
Authors: Zhang Fengshun , He Guansong , Xu Kangming , Wu Hong , Guo Shaoyun , Zhang Chaoliang 
Published: February 2014

AbstractTo further investigate the effect of petroleum resin on damping mechanism and different modes of motion of chlorinated butyl rubber (CIIR), two kinds of petroleum resins with different molecular structures, aliphatic C5 resin and aromatic C9 resin, were incorporated into CIIR. The experimental results showed that the aliphatic C5 resin exhibited a better miscibility with CIIR, compared with aromatic C9 resin. With increase in the content of the C5 resin, the α process and the α′ process of CIIR moved to the higher temperature but to different extents, and the effective damping temperature range was broadened remarkably. The CIIR/C9 resin blends showed two loss peaks, which corresponded to the CIIR matrix and the C9 resin dispersed phase, respectively. The C9 resin neither moved different relaxation modes of CIIR to room temperature nor enhanced the value of the loss damping peak. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40464.
Stabilization of pluronic gels in the presence of different polysaccharides
Authors: Kjøniksen Anna‐Lena , Calejo Maria Teresa , Zhu Kaizheng , Nyström Bo , Sande Sverre Arne 
Published: February 2014

ABSTRACTSeveral different polysaccharides have been added to pluronic F127 (poloxamer 407) gels to test their ability to stabilize the gels against dissolution in aqueous media over time. The studied polysaccharides include κ‐carrageenan, chitosan, hyaluronic acid, pectin, alginate, hydroxyethylcellulose, and ethyl(hydroxyethyl)cellulose. Although all the considered polysaccharides slowed down the dissolution time of the pluronic gels, unmodified polysaccharides only had a modest stabilization effect. However, hydrophobic modification of polysaccharides with a sufficiently long hydrocarbon chain (C16) was found to partly prevent the gels from dissolving for more than 6 months. Shorter hydrocarbon chains did not have the same effect, even at high degrees of hydrophobicity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40465.
Oriented covalent immobilization of esterase BioH on hydrophilic‐modified Fe3O4 nanoparticles
Authors: Li Rongrong , Jiang Ling , Ye Lidan , Lu Jie , Yu Hongwei 
Published: February 2014

AbstractThe esterase BioH from Escherichia coli was covalently immobilized onto the surface of the functional magnetic nanosupport in an oriented manner. The surface of the Fe3O4 nanosupport was modified with acyl azide groups or both acyl azide groups and hydroxyl groups. The protein loading of the support was increased from 55 to 99 mg/g by an improvement in hydrophilicity, and the activity retention of the immobilized esterase on the nanosupport was improved by 40% after hydrophilic modification (30% and 70% of the free BioH, respectively). For the BioH immobilized on the hydrophilic‐modified nanosupport, the recovery activity remained 80% of the original activity after 10 times of recycling. The catalytic kinetics and thermo‐/pH‐stability of the immobilized esterase BioH were also determined and compared with those of the free enzyme. The comparatively high activity retention, improved thermo‐/pH‐stability, and good reusability of the immobilized enzyme indicate that oriented covalent immobilization is an efficient method for immobilizing esterase BioH.