bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal climatology of CO2 across North America from aircraft measurements in the NOAA/ESRL Global Greenhouse Gas Reference Network
Authors: Sweeney Colm , Karion Anna , Wolter Sonja , Newberger Timothy , Guenther Doug , Higgs Jack A. , Andrews Arlyn Elyzabeth , Lang Patricia M. , Neff Don , Dlugokencky Edward , Miller John B. , Montzka Stephen A. , Miller Ben R. , Masarie Ken Alan , Biraud Sebastien Christophe , Novelli Paul C. , Crotwell Molly , Crotwell Andrew M. , Thoning Kirk , Tans Pieter P. 
Published: April 2015

AbstractSeasonal spatial and temporal gradients for the CO2 mole fraction over North America are examined by creating a climatology from data collected 2004–2013 by the NOAA/ESRL Global Greenhouse Gas Reference Network Aircraft Program relative to trends observed for CO2 at the Mauna Loa Observatory. The data analyzed are from measurements of air samples collected in specially fabricated flask packages at frequencies of days to months at 22 sites over continental North America and shipped back to Boulder, Colorado, for analysis. These measurements are calibrated relative to the CO2 World Meteorological Organization mole fraction scale. The climatologies of CO2 are compared to climatologies of CO, CH4, SF6, N2O (which are also measured from this sampling program), and winds to understand the dominant transport and chemical and biological processes driving changes in the spatial and temporal mole fractions of CO2 as air passes over continental North America. The measurements show that air masses coming off the Pacific on the west coast of North America are relatively homogeneous with altitude. As air masses flow eastward, the lower section from the surface to 4000 m above sea level (masl) becomes distinctly different from the 4000–8000 masl section of the column. This is due in part to the extent of the planetary boundary layer, which is directly impacted by continental sources and sinks, and to the vertical gradient in west‐to‐east wind speeds. The slowdown and southerly shift in winds at most sites during summer months amplify the summertime drawdown relative to what might be expected from local fluxes. This influence counteracts the dilution of summer time CO2 drawdown (known as the “rectifier effect”) as well as changes the surface influence “footprint” for each site. An early start to the summertime drawdown, a pronounced seasonal cycle in the column mean (500 to 8000 masl), and small vertical gradients in CO2, CO, CH4, SF6, and N2O at high‐latitude western sites such as Poker Flat, Alaska, suggest recent influence of transport from southern latitudes and not local processes. This transport pathway provides a significant contribution to the large seasonal cycle observed in the high latitudes at all altitudes sampled. A sampling analysis of the NOAA/ESRL CarbonTracker model suggests that the average sampling resolution of 22 days is sufficient to get a robust estimate of mean seasonal cycle of CO2 during this 10 year period but insufficient to detect interannual variability in emissions over North America.
Validation of TES ammonia observations at the single pixel scale in the San Joaquin Valley during DISCOVER‐AQ
Authors: Sun Kang , Cady‐Pereira Karen , Miller David J. , Tao Lei , Zondlo Mark A. , Nowak John B. , Neuman J. A. , Mikoviny Tomas , Müller Markus , Wisthaler Armin , Scarino Amy J. , Hostetler Chris A. 
Published: April 2015

AbstractAmmonia measurements from a vehicle‐based, mobile open‐path sensor and those from aircraft were compared with Tropospheric Emission Spectrometer (TES) NH3 columns at the pixel scale during the NASA Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality field experiment. Spatial and temporal mismatches were reduced by having the mobile laboratory sample in the same areas as the TES footprints. To examine how large heterogeneities in the NH3 surface mixing ratios may affect validation, a detailed spatial survey was performed within a single TES footprint around the overpass time. The TES total NH3 column above a single footprint showed excellent agreement with the in situ total column constructed from surface measurements with a difference of 2% (within the combined measurement uncertainties). The comparison was then extended to a TES transect of nine footprints where aircraft data (5–80 ppbv) were available in a narrow spatiotemporal window (<10 km, <1 h). The TES total NH3 columns above the nine footprints agreed to within 6% of the in situ total columns derived from the aircraft‐based measurements. Finally, to examine how TES captures surface spatial gradients at the interpixel scale, ground‐based, mobile measurements were performed directly underneath a TES transect, covering nine footprints within ±1.5 h of the overpass. The TES total columns were strongly correlated (R2 = 0.82) with the median NH3 mixing ratios measured at the surface. These results provide the first in situ validation of the TES total NH3 column product, and the methodology is applicable to other satellite observations of short‐lived species at the pixel scale.
Analysis of a seeder‐feeder and freezing drizzle event
Authors: Fernández‐González S. , Valero F. , Sánchez J. L. , Gascón E. , López L. , García‐Ortega E. , Merino A. 
Published: April 2015

AbstractSurface icing can cause dramatic consequences on human activities. What is more, numerical weather prediction models are not very accurate in determining freezing drizzle, which creates uncertainty when forecasting this type of weather phenomenon. Therefore, it is essential to improve the forecast accuracy of these models for such phenomena to mitigate risks caused by unforeseen freezing drizzle events. On 5 February 2012, an episode of freezing drizzle took place in the Guadarrama Mountains, at the center of the Iberian Peninsula. This episode was preceded by weak snowfall. After the freezing drizzle, moderate snowfall was recorded in the study area. This event was simulated using the Weather Research and Forecasting model. Through this analysis, we identified the meteorological factors at both synoptic scale and mesoscale that caused this episode. Wind perpendicular to an orographic barrier‐generated updrafts and retention of moisture upwind, which caused orographic clouds to appear on the north side of the Guadarrama Mountains. Atmospheric stability prevented cloud formation at midlevels at the time of the freezing drizzle, which maintained cloud top temperatures warmer than −15°C during the episode. The entrance of moisture and instability at midlevels caused cloud top temperatures substantially colder than −15°C, which coincided with snow in the mountain range. Cloud top temperature and thickness control the efficiency of the glaciation process, thereby determining the type of precipitation at the surface. Freezing drizzle risk and in‐cloud icing algorithms were developed with the aim of predicting similar events in the study area, which could mitigate impacts on human activities.
Estimating trends and seasonality in Australian monthly lightning flash counts
Authors: Bates Bryson C. , Chandler Richard E. , Dowdy Andrew J. 
Published: April 2015

AbstractWe present the results of a statistical analysis of lightning characteristics in mainland Australia for the period from approximately 1988 to 2012, based on monthly lightning flash count (LFC) series obtained from a network of 19 Comité Internationale des Grands Réseaux Electriques, 500 Hz peak transmission filter circuit sensors. The temporal structures of the series are examined in terms of detecting and characterizing seasonal cycles, long‐term trends, and changes in seasonality over time. A generalized additive modeling approach is used to ensure that the estimated structures are determined by the data, rather than by the constraints of any assumed mathematical form for the trends and seasonal cycle. Results indicate strong seasonality at all sites, the presence of long‐term trends at 16 sites, and interactions between trend and seasonality (corresponding to changes in seasonality over time) at 13 sites. The most systematic change corresponds to a progressive deepening of the seasonal cycle (i.e., an ongoing decline in winter lightning flash counts) and is most noticeable across southern Australia (south of 30°S). These results are consistent with previous analyses that have detected decreasing atmospheric instability during the austral winter since the mid‐1970s. This is associated with increasing mean sea level pressure and declining rainfall.
The equivalent slab thickness of Mars' ionosphere: Implications for thermospheric temperature
Authors: Mendillo M. , Narvaez C. , Lawler G. , Kofman W. , Mouginot J. , Morgan D. , Gurnett D. 
Published: April 2015

AbstractThe total electron content (TEC) of a planetary ionosphere is dominated by plasma near and above the height of maximum electron density (Nmax). The ratio TEC/Nmax represents the thickness (τ) of a TEC slab of uniform density (Nmax). For a photochemical ionosphere, τ relates to the scale height (H = kT/mg) of the ionized neutral gas as τ ~ 4 × H. Derived temperatures refer to ~160 km in thermosphere height—below the asymptotic temperature of the exosphere. The MARSIS instrument on Mars Express has produced data sets of TEC and Nmax. We used them to form τ patterns versus solar zenith angle and solar cycle phase. For daytime (SZA < 90°) conditions, <τ > day ~ 50 km, decreasing rapidly for solar zenith angle (SZA) > 90° to < τ > night ~ 25 km. These correspond to Tn values of 250°K and 125°K. Using Mars Global Surveyor data, τ patterns show a mild dependence upon the solar EUV flux proxy F10.7, with ΔTn(°K) ~ 0.3° per unit change in F10.7 at Mars.
Evidence for a wide and gently dipping Main Himalayan Thrust in western Bhutan
Authors: Le Roux‐Mallouf Romain , Godard Vincent , Cattin Rodolphe , Ferry Matthieu , Gyeltshen Jampel , Ritz Jean‐François , Drupka Dowchu , Guillou Valéry , Arnold M. , Aumaître G. , Bourlès D. L. , Keddadouche K. 
Published: April 2015

AbstractThe Main Himalayan Thrust (MHT) is the source of great earthquakes that have been documented along the range. Its geometry is a key parameter that influences accommodation of tectonic loading and earthquake magnitudes along the Himalayan Arc. Although seismic images are available for both the western and the central part of the range, this geometry remains poorly constrained for the Bhutanese Himalayas. Here we address this issue using a 10Be cosmogenic nuclides denudation transect across western Bhutan. We observe a wide low denudation rate domain between 50 km and 110 km from the front followed by a strong northward increase. Using a joint inversion of denudation rates, GPS data, and Holocene uplift rates, we interpret this pattern as a consequence of a flat‐ramp transition along the MHT. Compared to central Nepal and Sikkim, this location of the ramp suggests a wider décollement, with implications for greater seismogenic potential of the MHT in western Bhutan.
Localization and delocalization of deformation in a bimineralic material
Authors: Jammes Suzon , Lavier Luc L. , Reber Jacqueline E. 
Published: April 2015

AbstractWe investigate how localization and delocalization of deformation occurs in a bimineralic material composed of a strong plagioclase and a weaker quartz phase. We perform numerical, meter‐scale shear experiments in which we vary the temperature and the ratio of the two mineral phases. Three micromechanical deformation fields are identified according to the mechanical behavior of the minerals at play (brittle or ductile when both phases are in the brittle or ductile regime, respectively, and semibrittle when one phase is in the brittle and the other in the ductile regime). Besides these micromechanical deformation fields, we identify three deformation types characterizing the degree of localization (type I: localized shear zone, type II: localized anastomosing shear zone, and type III: delocalized shear zone). Type I is expected in the brittle deformation field. In the semibrittle field, all deformation types can be observed depending on the amount of weak phase present. In the ductile field, deformation is dependent on the strength ratio between the two phases. For a low strength ratio, deformation of type III is always observed. For high‐strength ratios, deformation of type II can be observed for a moderate amount of weak phase. A small amount of weak phase (<10%) reverses the mechanical behavior of the strong phase and leads to the formation of a narrow anastomosing shear zone (type II) where fully ductile (type III) behavior is expected. This highlights the importance of a bimineralic material for the deformation localization and overall large‐scale deformation processes.
Estimation of the time series of the meridional heat transport across 15°N in the Pacific Ocean from Argo and satellite data
Authors: Yang Tingting , Xu Yongsheng 
Published: April 2015

AbstractThe time series of the net meridional heat transport (MHT) at 15°N in the Pacific Ocean from 2003 to 2012 is estimated by combining the Argo profiles with the satellite altimeter and scatterometer data. The estimate is validated against the climatological ocean data and the ECCO2 products, and is demonstrated to be reasonable. The MHT has a high degree of variability with a temporal mean of 0.70 ± 0.31 PW, which is concentrated in the upper 800 dbar. The time series of the MHT and Ekman temperature transport have a significant annual cycle which peaks near April and December, whereas the time series of the geostrophic temperature transport have a subannual cycle. The results are consistent with previous estimates and lower than the ECCO2 estimate, which may mainly be caused by the different data sources and processings. The correlation between the air‐sea flux and MHT is 0.50 with a 3 month delay. This report describes the first such attempt at a continuous transport of heat at 15°N in the Pacific Ocean from in situ observations.
Epilepsy, cognitive deficits and neuroanatomy in males with ZDHHC9 mutations
Authors: Baker Kate , Astle Duncan E. , Scerif Gaia , Barnes Jessica , Smith Jennie , Moffat Georgina , Gillard Jonathan , Baldeweg Torsten , Raymond F. Lucy 
Published: April 2015

AbstractObjectiveSystematic investigation of individuals with intellectual disability after genetic diagnosis can illuminate specific phenotypes and mechanisms relevant to common neurodevelopmental disorders. We report the neurological, cognitive and neuroanatomical characteristics of nine males from three families with loss‐of‐function mutations in ZDHHC9 (OMIM #300799).MethodsAll known cases of X‐linked intellectual disability (XLID) due to ZDHHC9 mutation in the United Kingdom were invited to participate in a study of neurocognitive and neuroimaging phenotypes.ResultsSeven out of nine males with ZDHHC9 mutations had been diagnosed with epilepsy, exceeding epilepsy risk in XLID comparison subjects (P = 0.01). Seizure histories and EEG features amongst ZDHHC9 mutation cases shared characteristics with rolandic epilepsy (RE). Specific cognitive deficits differentiated males with ZDHHC9 mutations from XLID comparison subjects and converged with reported linguistic and nonlinguistic deficits in idiopathic RE: impaired oromotor control, reduced verbal fluency, and impaired inhibitory control on visual attention tasks. Consistent neuroanatomical abnormalities included thalamic and striatal volume reductions and hypoplasia of the corpus callosum.InterpretationMutations in ZDHHC9 are associated with susceptibility to focal seizures and specific cognitive impairments intersecting with the RE spectrum. Neurocognitive deficits are accompanied by consistent abnormalities of subcortical structures and inter‐hemispheric connectivity. The biochemical, cellular and network‐level mechanisms responsible for the ZDHHC9‐associated neurocognitive phenotype may be relevant to cognitive outcomes in RE.
Synthesis, structure, and properties of segmented carborane‐containing polyurethanes
Authors: Luo Yumeng , Lu Yafei , Li Ning , Li Yun , Zhang Xiaoa , Qi Shicheng 
Published: April 2015

ABSTRACTNovel segmented carborane‐containing polyurethane (PUR 2–5) is synthesized from hydroxyl‐terminated carborane‐containing prepolymer (P3) as soft segment and isocyanate‐terminated carborane‐containing prepolymer (P5) as hard segment by different ratio of P3 and P5. The prepared carborane‐containing polyarylesters and polyurethanes (PURs) are characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). Their mechanical properties and thermal stability are measured, while the dosage of carborane biphenol is 5–10 wt %, the tensile strength is up to 20 MPa, and thermal gravimetric analyzer (TGA) curves indicate that the carborane group effectively reduces the degradation rate of carborane‐containing polyurethane, which is fairly stable above 300°C and with char yield exceeding 40%. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42227.
Pyrolysis oil substituted epoxy resin: Improved ratio optimization and crosslinking efficiency
Authors: Celikbag Yusuf , Robinson Thomas J. , Via Brian K. , Adhikari Sushil , Auad Maria L. 
Published: April 2015

ABSTRACTThe objective of this study was to determine the compatibility of whole pyrolysis oil (PO) of pine as a substitute for the phenolic component of epoxy resins (ER). Pyrolysis oil‐based epoxy resin (POBER) was synthesized by modification of EPON828 ER with PO at various mixing ratios (1 : 3–1 : 8, PO:EPON828, w/w). Acetone extraction determined that a ratio of 1 : 7–1 : 8 resulted in a fully reacted thermoset, leaving neither PO nor EPON828 in a significantly unreacted state. Dynamic mechanical analysis (DMA) revealed that a ratio of 1 : 8 produced the highest storage modulus (E’); in addition, it was determined that this ratio provided a superior glass transition temperature (Tg) of 120°C and crosslinking density of 1891 mol/m3. FTIR spectra concluded that the reaction between the EPON828 and PO was complete at the 1 : 8 ratio, citing the removal of hydroxyl and epoxide peaks within the cured product. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42239.
Influence of hygrothermal aging on dimensional stability of thin injection‐molded short glass fiber reinforced PA6 materials
Authors: Illing Thomas , Schoßig Marcus , Bierögel Christian , Grellmann Wolfgang 
Published: April 2015

ABSTRACTThe hygrothermal aging of short glass fiber reinforced polyamide 6 materials (PA6/GF) is a major problem for thin‐walled components used in the automotive sector. In this work, the thickness and glass fiber content of PA6/GF materials were varied and exposed to hygrothermal aging. The temperature and relative humidity were chosen to range from −40 to 85°C and 10% RH to 85% RH respectively, according to automotive requirements for components in the passenger compartment. For the absorption of moisture, the diffusion behavior could not be generally described by Fick's law. However, the results indicate that the diffusion behavior is dependent on the relative humidity and thickness of the PA6/GF material. The morphology of the test specimen, which is influenced by injection molding, was also found to affect the diffusion behavior. The states of equilibrium for moisture absorption are strongly dependent on the relative humidity during hygrothermal aging and less dependent on the temperature. The maximum absorbed humidity was found at a temperature of 65°C and 85% RH, which was higher than at 85°C and 85% RH because of reduced contrary aging processes, such as postcrystallization. In certain climatic conditions and test specimen thicknesses, there was a characteristic overshoot in the mass change. This behavior could be attributed to a different degree of crystallization and lower glass fiber content. Both moisture absorption and an overshoot of the mass affected the dimensional stability of the test specimens. This effect on dimensional stability could be correlated with the glass fiber orientation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42245.
Solvent‐free acetylation of lignocellulosic fibers at room temperature: Effect on fiber structure and surface properties
Authors: El Boustani Meriem , Brouillette François , Lebrun Gilbert , Belfkira Ahmed 
Published: April 2015

ABSTRACTAcetylation is one of the most interesting chemical treatments to improve the affinity of lignocellulosic fibers with polymeric matrices for the elaboration of several types of composites. In this paper, the acetylation of flax and wood pulp (bleached softwood Kraft pulp and thermomechanical pulp) fibers was carried out at room temperature in a solvent‐free system with acetic anhydride in the presence of sulfuric acid as catalyst. The effect of acetylation on the fine structure of fibers was investigated by spectroscopic methods, while the extent of acetylation was quantified by weight percent gain. The effect of reaction time on fiber morphology was studied at macro‐ and microscale using scanning electron microscopy, optical microscopy, and fiber quality analysis. The evolution of the hydrophobic/hydrophilic character of fibers was determined by contact angle measurements. The wettability of fibers by liquid epoxy resin was also evaluated to confirm the improvement of the affinity of acetylated fibers with the epoxy matrix. It was found that the hydrophilic character of fibers decrease with increasing reaction time, whereas the trend was less pronounced beyond specific reaction times. Acetylated fibers can therefore be potential candidates for replacing nonbiodegradable reinforcing materials in composite applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42247.
Hybrid carrageenan‐based formulations for edible film preparation: Benchmarking with kappa carrageenan
Authors: Larotonda Fabio D. S. , Torres María D. , Gonçalves Maria P. , Sereno Alberto M. , Hilliou Loic 
Published: April 2015

ABSTRACTAn intense search for new renewable sources to produce natural polymers for edible and biodegradable packaging is observed as they offer lower environmental costs. The objective of this work is to investigate the use of hybrid carrageenan, extracted from Mastocarpus stellatus seaweeds, as an alternative to commercial kappa carrageenan in new edible film formulations. To this end, the production and characterization of biodegradable films obtained with mixtures of rice starch and hybrid carrageenan or commercial kappa carrageenan were carried out. Thin, flexible, and transparent films with attractive functional properties were obtained from rice starch–carrageenan mixtures. Films forming solutions produced with hybrid carrageenan showed rheological properties comparable to commercial kappa carrageenan‐based solutions. Films formulated with hybrid carrageenan show significantly enhanced UV barrier, oxygen barrier, and hydrophobic properties. Thus, hybrid carrageenan proved to be a promising material for the production of edible coatings and biodegradable films and a good alternative to kappa carrageenan for such application. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42263.