bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aquarius geophysical model function and combined active passive algorithm for ocean surface salinity and wind retrieval
Authors: Yueh Simon , Tang Wenqing , Fore Alexander , Hayashi Akiko , Song Yuhe T. , Lagerloef Gary 
Published: August 2014

AbstractThis paper describes the updated Combined Active‐Passive (CAP) retrieval algorithm for simultaneous retrieval of surface salinity and wind from Aquarius' brightness temperature and radar backscatter. Unlike the algorithm developed by Remote Sensing Systems (RSS), implemented in the Aquarius Data Processing System (ADPS) to produce Aquarius standard products, the Jet Propulsion Laboratory's CAP algorithm does not require monthly climatology SSS maps for the salinity retrieval. Furthermore, the ADPS‐RSS algorithm fully uses the National Center for Environmental Predictions (NCEP) wind for data correction, while the CAP algorithm uses the NCEP wind only as a constraint. The major updates to the CAP algorithm include the galactic reflection correction, Faraday rotation, Antenna Pattern Correction, and geophysical model functions of wind or wave impacts. Recognizing the limitation of geometric optics scattering, we improve the modeling of the reflection of galactic radiation; the results are better salinity accuracy and significantly reduced ascending‐descending bias. We assess the accuracy of CAP's salinity by comparison with ARGO monthly gridded salinity products provided by the Asia‐Pacific Data‐Research Center (APDRC) and Japan Agency for Marine‐Earth Science and Technology (JAMSTEC). The RMS differences between Aquarius CAP and APDRC's or JAMSTEC's ARGO salinities are less than 0.2 psu for most parts of the ocean, except for the regions in the Intertropical Convergence Zone, near the outflow of major rivers and at high latitudes.
Observations of rain‐induced near‐surface salinity anomalies
Authors: Asher William E. , Jessup Andrew T. , Branch Ruth , Clark Dan 
Published: August 2014

AbstractVertical salinity gradients in the top few meters of the ocean surface can exist due to the freshwater input from rain. If present, surface gradients complicate comparing salinity measured at depths of a few meters to salinities retrieved using L‐band microwave radiometers such as SMOS and Aquarius. Therefore, understanding the spatial scales and the frequency of occurrence of these vertical gradients and the conditions under which they form will be important in understanding sea surface salinity maps provided by microwave radiometers. Salinity gradients in the near‐surface ocean were measured using a towed profiler that profiled salinity in the top 2 m of the ocean with a minimum measurement depth of 0.1 m. In addition, an Underway Salinity Profiling System was installed on the R/V Thomas G. Thompson. This measured near‐surface salinity at depths of 1 and 2 m. Both the towed profiler and the underway system found the occurrence of negative salinity anomalies (i.e., salinity decreasing toward the surface) was correlated with the presence of rain. The magnitude of the anomaly (i.e., the difference between salinity at 0.1 m and the salinity at 0.26 m) was proportional to the cube of the rain rate for rain rate, R, greater than 6 mm h−1. From this, for R > 15–22 mm h−1, depending on the areal extent of the salinity anomalies, rain can cause scene‐averaged salinity offsets that are as large as the accuracy goal for Aquarius of 0.1‰.
Interdecadal changes in snow depth on Arctic sea ice
Authors: Webster Melinda A. , Rigor Ignatius G. , Nghiem Son V. , Kurtz Nathan T. , Farrell Sinead L. , Perovich Donald K. , Sturm Matthew 
Published: August 2014

AbstractSnow plays a key role in the growth and decay of Arctic sea ice. In winter, it insulates sea ice from cold air temperatures, slowing sea ice growth. From spring to summer, the albedo of snow determines how much insolation is absorbed by the sea ice and underlying ocean, impacting ice melt processes. Knowledge of the contemporary snow depth distribution is essential for estimating sea ice thickness and volume, and for understanding and modeling sea ice thermodynamics in the changing Arctic. This study assesses spring snow depth distribution on Arctic sea ice using airborne radar observations from Operation IceBridge for 2009–2013. Data were validated using coordinated in situ measurements taken in March 2012 during the Bromine, Ozone, and Mercury Experiment (BROMEX) field campaign. We find a correlation of 0.59 and root‐mean‐square error of 5.8 cm between the airborne and in situ data. Using this relationship and IceBridge snow thickness products, we compared the recent results with data from the 1937, 1954–1991 Soviet drifting ice stations. The comparison shows thinning of the snowpack, from 35.1 ± 9.4 to 22.2 ± 1.9 cm in the western Arctic, and from 32.8 ± 9.4 to 14.5 ± 1.9 cm in the Beaufort and Chukchi seas. These changes suggest a snow depth decline of 37 ± 29% in the western Arctic and 56 ± 33% in the Beaufort and Chukchi seas. Thinning is negatively correlated with the delayed onset of sea ice freezeup during autumn.
Sea surface salinity under rain cells: SMOS satellite and in situ drifters observations
Authors: Boutin J. , Martin N. , Reverdin G. , Morisset S. , Yin X. , Centurioni L. , Reul N. 
Published: August 2014

AbstractWe study the signature of rainfall on S1cm, the sea surface salinity retrieved from the Soil Moisture and Ocean Salinity (SMOS) satellite mission first by comparing SMOS S1cm with ARGO sea surface salinity measured at about 5 m depth in the Intertropical Convergence Zone (ITCZ) and in the Southern Pacific Convergence Zone; second by investigating spatial variability of SMOS S1cm related to rainfall. The resulting estimated S1cm decrease associated with rainfall occurring within less than 1 h from the salinity measurement is close to −0.2 pss (mm h−1) −1. We estimate that rain induced roughness and atmospheric effects are responsible for no more than 20% of this value. We also study the signature of rainfall on sea surface salinity measured by surface drifters at 45 cm depth and find a decrease associated with rainfall of −0.21 (±0.14) pss (mm h−1) −1, consistent with SMOS observations. When averaged over one month, this rain associated salinity decrease is at most −0.2 in monthly 100 × 100 km2 pixels, and at most 40% of the difference between SMOS S1cm and interpolated in situ bulk salinity in pixels near the ITCZ. This suggests that more than half of this difference is related to the in situ products obtained from optimal interpolation and therefore influenced by smoothing and relaxation to climatology. Finally, further studies on the satellite‐derived salinities should pay attention to that as well as to other sources of uncertainties in satellite measurements and not interpret fully the observed differences between in situ and satellite mapped products, as rain induced SSS variability.
Validation of Aquarius sea surface salinity with in situ measurements from Argo floats and moored buoys
Authors: Tang Wenqing , Yueh Simon H. , Fore Alexander G. , Hayashi Akiko 
Published: August 2014

AbstractWe validate sea surface salinity (SSS) retrieved from Aquarius instrument on SAC‐D satellite with in situ measurements by Argo floats and moored buoy arrays. We assess the error structure of three Aquarius SSS products: the standard product processed by Aquarius Data Processing System (ADPS) and two data sets produced at the Jet Propulsion Laboratory (JPL): the Combined Active‐Passive algorithm with and without rain correction, CAP and CAP_RC, respectively. We examine the effect of various filters to prevent unreliable point retrievals from entering Level 3 averaging, such as land or ice contamination, radio frequency interference (RFI), and cold water. Our analyses show that Aquarius SSS agrees well with Argo in a monthly average sense between 40°S and 40°N except in the Eastern Pacific Fresh Pool and Amazon River outflow. Buoy data within these regions show excellent agreement with Aquarius but have discrepancies with the Argo gridded products. Possible reasons include strong near‐surface stratification and sampling problems in Argo in regions with significant western boundary currents. We observe large root‐mean‐square (RMS) difference and systematic negative bias between ADPS and Argo in the tropical Indian Ocean and along the Southern Pacific Convergence Zone. Excluding these regions removes the suspicious seasonal peak in the monthly RMS difference between the Aquarius SSS products and Argo. Between 40°S and 40°N, the RMS difference for CAP is less than 0.22 PSU for all 28 months, CAP_RC has essentially met the monthly 0.2 PSU accuracy requirement, while that for ADPS fluctuates between 0.22 and 0.3 PSU.
Comparison of low‐level jets along the north coast of China in summer
Authors: Wei W. , Zhang H. S. , Ye X. X. 
Published: August 2014

AbstractA data set obtained from wind‐profile radars located along the north coast of China in summer was used to compare the characteristics of the low‐level jets (LLJs) at two different sites, Tianjin and Shanghai. In this paper, the characteristics and evolutions of the low‐level jets were investigated, and the inertial oscillations were analyzed by the Hilbert‐Huang transform technique. The results showed that LLJs (≤14 m s−1) dominate at both Tianjin and Shanghai, with percentages of 76.5% and 84.8%, respectively. In terms of LLJ strength and frequency of appearance, evident diurnal changes were detected at the two sites, and nocturnal LLJs overwhelmed daytime LLJs in both strength and frequency. Influenced by the local topography and synoptic forcing, the LLJs were characterized by totally different distributions of wind directions and heights. The preferred direction at Shanghai was from the southwest and east, whereas northeast and south directions dominated at Tianjin. In the matter of jet heights, LLJs at Shanghai tended to occur at more consistent levels (56.3% of observed LLJs below 600 m) than at Tianjin. The LLJ wind speed shear at Shanghai was also stronger than that at Tianjin. The Hilbert‐Huang transform technique was applied to reveal the intrinsic mode functions with cycles of local inertial oscillation (19 h for Tianjin and 23 h for Shanghai), and the patterns of inertial oscillation power agreed with the time‐height distribution of the observed LLJs.
The landscape of Titan as witness to its climate evolution
Authors: Moore Jeffrey M. , Howard Alan D. , Morgan Alexander M. 
Published: August 2014

AbstractWe investigated the range of Titan climate evolution hypotheses regulated by the role, sources, and availability of methane. We analyzed all available image data (principally synthetic aperture radar (SAR)) of Titan's landscape through the T‐86 encounter, starting with focused examinations of terrains that carry the markers of climate evolution. Traditional geologic and geomorphic landscape analysis was used to perform morphometric characterization, establish time‐stratigraphic relationships, and interpret local and regional geologic process‐oriented evolutionary histories. We then assayed the distribution of terrains we identified with respect to both their latitudinal and altimetric occurrence. Our analysis of the terrain types and distributions was used to evaluate and rank the various climate evolution scenarios. We favor progressive hypotheses, which include a relatively brief period in which precipitation was able to affect geomorphic change in low latitudes at scales perceivable in SAR data, with subsequent gradual decline of precipitation intensity coupled with an increasing poleward restriction.
A homogenization technique for obtaining generalized sheet transition conditions for an arbitrarily shaped coated wire grating
Authors: Holloway Christopher L. , Kuester Edward F. , Dienstfrey Andrew 
Published: August 2014

AbstractUsing a multiple‐scale homogenization method, we derive generalized sheet transition conditions (GSTCs) for an arbitrarily shaped coated wire grating. The parameters in these GSTCs are interpreted as effective electric and magnetic surface susceptibilities and surface porosities of the wire grating. We give expressions for determining these surface parameters for any arbitrarily shaped grating. We show that these GSTCs are a generalized form of the boundary conditions derived earlier by Wainstein and Sivov, who analyzed the case of symmetric, uncoated wire gratings. This work is also a first step in developing GSTCs for more general types of structures such as metasurfaces, metafilms, and metascreens.
Exceedingly Fast Copper(II)‐Promoted ortho CH Trifluoromethylation of Arenes using TMSCF3
Authors: Shang Ming , Sun Shang‐Zheng , Wang Hong‐Li , Laforteza Brian N. , Dai Hui‐Xiong , Yu Jin‐Quan 
Published: August 2014

AbstractThe direct ortho‐trifluoromethylation of arenes, including heteroarenes, with TMSCF3 has been accomplished by a copper(II)‐promoted CH activation reaction which completes within 30 minutes. Mechanistic investigations are consistent with the involvement of CH activation, rather than a simple electrophilic aromatic substitution (SEAr), as the key step.
Enhancement of pervaporation performance of composite membranes through in situ generation of silver nanoparticles in poly(vinyl alcohol) matrix
Authors: Premakshi H.G. , Sajjan Ashok M. , Kittur Arjumand A. , Kariduraganavar Mahadevappa Y. 
Published: August 2014

ABSTRACTComposite membranes were prepared from an aqueous solution of poly(vinyl alcohol) (PVA) and silver sulphate. The silver nanoparticles were generated in situ before crosslinking PVA matrix by reduction of silver ions using sodium borohydride. Physico‐chemical properties of the resulting composite membranes were studied using Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy (UV–vis), thermogravimetric analysis (TGA), Wide‐angle X‐ray diffraction (WAXD), scanning electron microscopy (SEM), and universal testing machine (UTM). The UV–vis spectrum shows a single peak at 410 nm due to surface plasmon absorption of silver nanoparticles. This surely specified that silver nanoparticles are generated in PVA matrix. The membranes were under go pervaporation (PV) for separation of water from isopropanol at different temperatures. The results indicated that hydrophilicity and amorphous nature of the membranes were increased with increasing silver nanoparticles in PVA matrix. The swelling and separation performance of the membranes were studied. Both permeation flux and separation factor were increased with increasing silver nanoparticles in PVA matrix. The results showed that the membrane containing 2.5 mass% of Ag salt exhibited excellent PV performance. The values of total flux and flux of water are almost closed to each other, indicating that membranes could be effectively used to break the azeotropic point of water‐isopropanol. The long‐term test was performed at room temperature and ascertained that membranes were durable up to 30 days for the dehydration of IPA. On the basis of the estimate Arrhenius activation energy values, the efficiency of the membranes was discussed. The calculated ΔHs values are negative for all the membranes, indicating that Longmuir's mode of sorption is predominant. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41248.
Physico‐chemical, thermal, and mechanical approaches for the characterization of solubilized and solid state chitosans
Authors: Mati‐Baouche Narimane , De Baynast Hélène , Vial Christophe , Audonnet Fabrice , Sun Shengnan , Petit Emmanuel , Pennec Fabienne , Prevot Vanessa , Michaud Philippe 
Published: August 2014

ABSTRACTThis study was conducted on the both solid and solubilized chitosans to propose an approach for the physico‐chemical, thermal and mechanical characterizations of this polysaccharide. The polysaccharide used was a 90% deacetylated chitosan having a molecular weight of 98.4 kDa. The flow property of chitosan solutions was evaluated revealing a shear‐thinning behavior. The thermal characterization was carried out by studying heat specific capacity, glass transition temperature, and thermal conductivity on chitosan dried specimens (solid state). Their Tg were measured by DSC and confirmed by DMA at 102 and 122°C depending on concentrations of initial chitosan solutions. The mechanical characterization was conducted by analyzing Young modulus, tensile strength, and elongation at break of chitosan specimens. They exhibited a higher elongation at break and a lower tensile strength when made from high concentrated chitosan solution (9% w/v). Differences in mechanical behavior of specimens were explained by differences of crystallinity. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41257.
LDPE/clay/carvacrol nanocomposites with prolonged antimicrobial activity
Authors: Shemesh Rotem , Goldman Diana , Krepker Maksym , Danin‐Poleg Yael , Kashi Yechezkel , Vaxman Anita , Segal Ester 
Published: August 2014

ABSTRACTOver the past decade there is an immense effort to develop antimicrobial packaging systems, which incorporates natural biopreservatives, such as essential oils (EOs). The highly volatile nature of EOs, which is advantageous for their efficient diffusion and mode of action, presents a major obstacle for their incorporation with polyolefins via conventional high‐temperature melt compounding and processing. This study presents a new approach to use organo‐modified montmorillonite (MMT) clays, as active carriers for carvacrol (used as a model EO), aiming to minimize its loss throughout the polymer compounding. Different MMT clays are pretreated with carvacrol, resulting in the oil molecules intercalation in between the clay galleries and enhanced carvacrol thermal stability. These hybrids are incorporated within low‐density polyethylene (LDPE) and the resulting films are characterized in terms of their nanostructure, thermal properties, and antimicrobial activity. The LDPE/(clay/carvacrol) nanocomposites exhibit excellent and prolonged antimicrobial activity againstE. colibacteria, while LDPE/carvacrol films loss their antimicrobial functions within several days. The superior antimicrobial behavior is ascribed to the significantly higher carvacrol content and its enhanced thermal stability within the films. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41261.
Preparation and properties of phase‐change heat‐storage UV curable polyurethane acrylate coating
Authors: Shi Yeting , Wu Yijian , Zhu Lizhi , Shentu Baoqing , Weng Zhixue 
Published: August 2014

ABSTRACTPhase‐change heat‐storage UV curable polyurethane acrylate (PUA) coating was prepared by applying microencapsulated phase change materials (microPCMs) to PUA coating. MicroPCMs containing paraffin core with melamine‐formaldehyde shell were synthesized by in situ polymerization. The effect of stirring speed, emulsification time, emulsifier amount, and core/shell mass ratio on particle size, morphology, and phase change properties of the microPCMs was studied by using laser particle size analyzer, Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopic analysis, scanning electron microscopy, and differential scanning calorimetry. The results showed that the diameter of the microcapsules decreased with the increase of stirring speed, emulsification time, and emulsifier amount. When the mass ratio of emulsifier to paraffin is 6%, microcapsules fabricated with a core/shell ratio of 75/25 have a compact surface and a mean particle size of 30 μm. The sample made under the above conditions has a higher efficiency of microencapsulation than other samples and was applied to PUA coating. The dispersion of microPCMs in coating and heat‐storage properties of the coating were investigated. The results illustrated that the phase‐change heat‐storage UV curable PUA coating can store energy and insulate heat. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41266.
Fabrication of a low‐cost nano‐SiO2/PVC composite ultrafiltration membrane and its antifouling performance
Authors: Yu Zhenjiang , Liu Xuyang , Zhao Fangbo , Liang Xiaoyang , Tian Yu 
Published: August 2014

ABSTRACTA novel low‐cost SiO2/Polyvinylchloride (PVC) membrane with different nano‐SiO2 particles loading (0–4 wt %) was prepared by the phase‐inversion process. The optimum nano‐SiO2 dosage was determined as 1.5 wt % based on the casting solution compositions, the membranes' mechanical properties and hydrophilicities, the pure water fluxes, microstructures, and absorption of protein. Compared with the bare membrane, the membrane with 1.5 wt % nano‐SiO2 addition presented better capabilities against the protein absorption and bacterial attachment, better antifouling performance, and higher flux recovery ratio in filtration of the supernatant liquor which collected from a secondary sedimentation tank in a municipal wastewater plant. The SiO2/PVC membranes have applicable potential in the municipal wastewater treatment for their low price, good antifouling performance and high removal efficiencies of SS (over 97.2%), COD (up to 82.9%) and total bacteria (more than 93.6%). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41267.
A novel method of making PVF porous foam without using the pore forming agent
Authors: Chang You‐Im , Cheng Wei‐You , Jang Larry 
Published: August 2014

ABSTRACTDifferent with the conventional method of manufacturing poly(vinyl formal) (PVF) porous foam by using the pore‐forming agents such as wheat or potato starches, a novel method without using the pore‐forming agent is introduced in this article. Through the help of images taken by a scanning electron microscope, the formation process of the present PVF foam will be discussed in terms of the spinodal decomposition (SD) phase separation principle. Additionally, the effect of poly(vinyl alcohol) concentration and reaction temperature on the pore structure of the PVF foam will be investigated. Moreover, the water adsorption capacities of the PVF foams obtained by the present method will be studied in details through the analyses of pore‐size distribution, mechanical modulus, and thermal property. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41270.
Synthesis and characterization of sustainable polyurethane modified by cyclic polysiloxane
Authors: Sheng Yingpei , Jiang Pingping , Zhang Duyang , Hua Jingyu 
Published: August 2014

ABSTRACTIn this article, a series of sustainable polyurethanes are prepared by introducing different content of cyclic polysilanol, which may act as a chain extender to replace 1, 4‐butanediol (BDO). Consequently, cyclic polysiloxanes are successfully incorporated into the molecular chains to afford organic–inorganic polyurethanes and then their effects on polyurethanes thermal properties and surface hydrophilicity are fully characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and contact angle testing. Results show that the hybrid polyurethanes display enhanced glass transition temperatures (Tg). While in terms of TGA, the effects of cyclic polysilanol on thermal properties seem complex, which would reduce the thermal stability in the first degradation process but enhance in the second process. The morphology observed by scanning electron microscopy (SEM) show that the inorganic constitutions, namely, cyclic polysilanol, may occur to self‐condensation or aggregation, which can help to explain the uncommon thermal phenomenon above. Thus, an opportunity of future applicability in the areas of sustainable polymer with improved properties can be envisioned in our research method of hybrid polyurethanes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41277.