bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improving air quality model predictions of organic species using measurement-derived organic gaseous and particle emissions in a petrochemical-dominated region
Authors: Stroud Craig A. , Makar Paul A. , Zhang Junhua , Moran Michael D. , Akingunola Ayodeji , Li Shao-Meng , Leithead Amy , Hayden Katherine , Siu May 
Published: September 2018

Abstract. This study assesses the impact of revised volatile organic compound (VOC) and organic aerosol (OA) emissions estimates in the GEM-MACH (Global Environmental Multiscale–Modelling Air Quality and CHemistry) chemical transport model (CTM) on air quality model predictions of organic species for the Athabasca oil sands (OS) region in Northern Alberta, Canada. The first emissions data set that was evaluated (base-case run) makes use of regulatory-reported VOC and particulate matter emissions data for the large oil sands mining facilities. The second emissions data set (sensitivity run) uses total facility emissions and speciation profiles derived from box-flight aircraft observations around specific facilities. Large increases in some VOC and OA emissions in the revised-emissions data set for four large oil sands mining facilities and decreases for others were found to improve the modeled VOC and OA concentration maxima in facility plumes, as shown with the 99th percentile statistic and illustrated by case studies. The results show that the VOC emission speciation profile from each oil sand facility is unique and different from standard petrochemical-refinery emission speciation profiles used for other regions in North America. A significant increase in the correlation coefficient is reported for the long-chain alkane predictions against observations when using the revised emissions based on aircraft observations. For some facilities, larger long-chain alkane emissions resulted in higher secondary organic aerosol (SOA) production, which improved OA predictions in those plumes. Overall, the use of the revised-emissions data resulted in an improvement of the model mean OA bias; however, a decrease in the OA correlation coefficient and a remaining negative bias suggests the need for further improvements to model OA emissions and formation processes. The weight of evidence suggests that the top-down emission estimation technique helps to better constrain the fugitive organic emissions in the oil sands region, which are a challenge to estimate given the size and complexity of the oil sands operations and the number of steps in the process chain from bitumen extraction to refined oil product. This work shows that the top-down emissions estimation technique may help to constrain bottom-up emission inventories in other industrial regions of the world with large sources of VOCs and OA.
Impact of low-pressure systems on winter heavy air pollution in the northwest Sichuan Basin, China
Authors: Ning Guicai , Wang Shigong , Yim Steve Hung Lam , Li Jixiang , Hu Yuling , Shang Ziwei , Wang Jinyan , Wang Jiaxin 
Published: September 2018

Abstract. The cities of Chengdu, Deyang, and
Mianyang in the northwest Sichuan Basin are part of a rapidly developing
urban agglomeration adjoining the eastern slopes of the Tibetan Plateau.
Heavy air pollution events have frequently occurred over these cities in recent
decades, but the effects of meteorological conditions on these pollution
events are unclear. We explored the effects of weather systems on winter
heavy air pollution from 1 January 2006 to 31 December 2012 and from
1 January 2014 to 28 February 2017. A total of 10 heavy air pollution events occurred
during the research period and 8 of these took place while the region was
affected by a dry low-pressure system at 700 hPa. When the urban
agglomeration was in front of the low-pressure system and the weather
conditions were controlled by a warm southerly air flow, a strong
temperature inversion appeared above the atmospheric boundary layer acting as
a lid. Forced by this strong inversion layer, the local secondary circulation
was confined to the atmospheric boundary layer, and the horizontal wind
speed in the lower troposphere was low. As a result, vertical mixing and
horizontal dispersion in the atmosphere were poor, favoring the formation of
heavy air pollution events. After the low-pressure system had transited over
the region, the weather conditions in the urban agglomeration were controlled
by a dry and cold air flow from the northwest at 700 hPa. The strong
inversion layer gradually dissipated, the secondary circulation enhanced and
uplifted, and the horizontal wind speed in the lower troposphere also
increased, resulting in a sharp decrease in the concentration of air
pollutants. The strong inversion layer above the atmospheric boundary layer
induced by the low-pressure system at 700 hPa thus played a key role in the
formation of heavy air pollution during the winter months in this urban
agglomeration. This study provides scientific insights for forecasting heavy
air pollution in this region of China.
Measuring turbulent CO2 fluxes with a closed-path gas analyzer in a marine environment
Authors: Honkanen Martti , Tuovinen Juha-Pekka , Laurila Tuomas , Mäkelä Timo , Hatakka Juha , Kielosto Sami , Laakso Lauri 
Published: September 2018

Abstract. In this study, we introduce new observations of sea–air fluxes of carbon
dioxide using the eddy covariance method. The measurements took place at the
Utö Atmospheric and Marine Research Station on the island of Utö in the
Baltic Sea in July–October 2017. The flux measurement system is based on a
closed-path infrared gas analyzer (LI-7000, LI-COR) requiring only occasional
maintenance, making the station capable of continuous monitoring. However,
such infrared gas analyzers are prone to significant water vapor interference
in a marine environment, where CO2 fluxes are small. Two LI-7000 analyzers were run in parallel to test the effect of a sample air
drier which dampens water vapor fluctuations and a virtual impactor,
included to remove liquid sea spray, both of which were attached to the
sample air tubing of one of the analyzers. The systems showed closely similar
(R2=0.99) sea–air CO2 fluxes when the latent heat flux was low, which
proved that neither the drier nor the virtual impactor perturbed the CO2
flux measurement. However, the undried measurement had a positive bias that
increased with increasing latent heat flux, suggesting water vapor
interference. For both systems, cospectral densities between vertical wind speed and CO2
molar fraction were distributed within the expected frequency range, with a
moderate attenuation of high-frequency fluctuations. While the setup equipped
with a drier and a virtual impactor generated a slightly higher flux loss, we
opt for this alternative for its reduced water vapor cross-sensitivity and
better protection against sea spray. The integral turbulence characteristics
were found to agree with the universal stability dependence observed over
land. Nonstationary conditions caused unphysical results, which resulted in
a high percentage (65 %) of discarded measurements. After removing the
nonstationary cases, the direction of the sea–air CO2 fluxes was in good
accordance with independently measured CO2 partial pressure difference
between the sea and the atmosphere. Atmospheric CO2 concentration changes
larger than 2 ppm during a 30 min averaging period were found
to be associated with the nonstationarity of CO2 fluxes.
The ionospheric response over the UK to major bombing raids during World War II
Authors: Scott Christopher J. , Major Patrick 
Published: September 2018

Abstract. The Earth's ionosphere is subject to disturbance from above (via solar
variability and space-weather effects) and from below (such as tectonic
activity, thunderstorms and sudden stratospheric warmings). Identifying the
relative contribution of these effects remains challenging, despite recent
advances in spacecraft monitoring near-Earth space. Man-made explosions
provide a quantifiable proxy for natural terrestrial sources, enabling their
impact on ionospheric variability to be studied. In this paper, the
contribution of ground-based disturbances to ionospheric variability is
investigated by considering the response of the ionospheric F2 layer over
Slough, UK, to 152 major bombing raids over Europe during World War II, using
a superposed epoch analysis. The median response of the F2 layer is a
significant decrease in peak electron concentration (∼0.3 MHz decrease
in foF2). This response is consistent with wave energy heating the
thermosphere, enhancing the (temperature-dependent) loss rate of O+
ions. The analysis was repeated for a range of thresholds in both time of
bombing before the (noon) ionospheric measurement and tonnage of bombs
dropped per raid. It was found that significant (∼2–3σ)
deviations from the mean occurred for events occurring between approximately
3 and 7 h ahead of the noon ionospheric measurements and for raids using a
minimum of between 100 and 800 t of high explosives. The most
significant ionospheric response (2.99σ) occurred for 20 raids up to
5 h before the ionospheric measurement, each with a minimum of 300 t of
explosives. To ensure that the observed ionospheric response cannot be
attributable to space-weather sources, the analysis was restricted to those
events for which the geomagnetic Ap index was less than 48 (Kp<5). Digitisation of the early ionospheric data would enable the
investigation into the response of additional ionospheric parameters
(sporadic E, E and F1 layer heights and peak concentrations). One metric ton
of TNT has an explosive energy of 4.184×109 J, which is of the
same order of energy as a cloud to ground lightning stroke. Since the
occurrence of lightning has distinctive diurnal and seasonal cycles, it is
feasible that a similar mechanism could contribute to the observed seasonal
anomaly in ionospheric F-region electron concentrations. Further
investigation, using less extreme examples, is required to determine the
minimum explosive energy required to generate a detectable ionospheric
response.
Legacies of past land use have a stronger effect on forest carbon exchange than future climate change in a temperate forest landscape
Authors: Thom Dominik , Rammer Werner , Garstenauer Rita , Seidl Rupert 
Published: September 2018

Abstract. Forest ecosystems play an important role in the global climate
system and are thus intensively discussed in the context of climate change
mitigation. Over the past decades temperate forests were a carbon (C) sink to
the atmosphere. However, it remains unclear to which degree this C uptake is
driven by a recovery from past land use and natural disturbances or ongoing
climate change, inducing high uncertainty regarding the future temperate
forest C sink. Here our objectives were (i) to investigate legacies within
the natural disturbance regime by empirically analyzing two disturbance
episodes affecting the same landscape 90 years apart, and (ii) to unravel the
effects of past land use and natural disturbances as well as the future climate
on 21st century forest C uptake by means of simulation modeling. We
collected historical data from archives to reconstruct the vegetation and
disturbance history of a forest landscape in the Austrian Alps from 1905 to
2013. The effects of legacies and climate were disentangled by individually controlling for past land use, natural disturbances, and future scenarios of
climate change in a factorial simulation study. We found only moderate
spatial overlap between two episodes of wind and bark beetle disturbance
affecting the landscape in the early 20th and 21st century,
respectively. Our simulations revealed a high uncertainty about the
relationship between the two disturbance episodes, whereas past land use
clearly increased the impact of the second disturbance episode on the
landscape. The future forest C sink was strongly driven by the cessation of
historic land use, while climate change reduced forest C uptake. Compared to
land-use change the two past episodes of natural disturbance had only
marginal effects on the future carbon cycle. We conclude that neglecting
legacies can substantially bias assessments of future forest dynamics.
Development of soil moisture profiles through coupled microwave–thermal infrared observations in the southeastern United States
Authors: Mishra Vikalp , Cruise James F. , Hain Christopher R. , Mecikalski John R. , Anderson Martha C. 
Published: September 2018

Abstract. The principle of maximum entropy (POME) can be used to develop
vertical soil moisture (SM) profiles. The minimal inputs required by the POME
model make it an excellent choice for remote sensing applications. Two of the
major input requirements of the POME model are the surface boundary condition
and profile-mean moisture content. Microwave-based SM estimates from the Advanced
Microwave Scanning Radiometer (AMSR-E) can supply the surface boundary
condition whereas thermal infrared-based moisture estimated from the
Atmospheric Land EXchange Inverse (ALEXI) surface energy balance model can
provide the mean moisture condition. A disaggregation approach was followed
to downscale coarse-resolution (∼25 km) microwave SM estimates to match
the finer resolution (∼5 km) thermal data. The study was conducted over
multiple years (2006–2010) in the southeastern US. Disaggregated soil
moisture estimates along with the developed profiles were compared with the
Noah land surface model (LSM), as well as in situ measurements from 10
Natural Resource Conservation Services (NRCS) Soil Climate Analysis Network
(SCAN) sites spatially distributed within the study region. The overall
disaggregation results at the SCAN sites indicated that in most cases
disaggregation improved the temporal correlations with unbiased root mean
square differences (ubRMSD) in the range of 0.01–0.09 m3 m−3. The
profile results at SCAN sites showed a mean bias of 0.03 and 0.05
(m3 m−3); ubRMSD of 0.05 and 0.06 (m3 m−3); and correlation
coefficient of 0.44 and 0.48 against SCAN observations and Noah LSM,
respectively. Correlations were generally highest in agricultural areas where
values in the 0.6–0.7 range were achieved.
Monitoring of seasonal variability and movement of suspended sediment concentrations along the Thiruvananthapuram coast, southern India, using the Landsat OLI sensor
Authors: Tripathy Bismay Ranjan , Seenipandi Kaliraj , Sajjad Haroon , Joshi Pawan Kumar , Chaudhary Bhagwan Singh , Kumar Pavan 
Published: September 2018

Abstract. Studies on suspended sediment concentrations at a
seasonal scale play a vital role in understanding coastal hydrodynamic
processes in an area. Assessment of spatio-temporal changes in suspended
sediments in nearshore areas has gained complexity due to the utilization of
conventional methods; this issue can be successfully
solved nowadays using multi-temporal remotely sensed images with the help of
advanced image processing techniques. The present study is an attempt to
demonstrate the model algorithm used to extract suspended sediment
concentrations using Landsat 8 OLI (Operational Land Imager) sensor images.
The study was executed in a near-offshore area of the Thiruvananthapuram
coast, southern India, and focused on the extraction of suspended sediment
concentrations and their seasonal variability during pre-monsoon and
post-monsoon periods. The OLI images were pre-processed to obtain the actual
reflectance using the FLASSH module of the ENVI v5.5 software. The generic
model developed herein is designed to compute the spectral reflectance
variability between coastal water and suspended sediments and to
differentiate the spatial accumulation of the suspended sediment
concentrations from the coastal water at the pixel scale. Maximum (0.8 % in
near-infrared bands) and minimum (0.6 % in blue bands) spectral reflectance
indicates the occurrence of suspended sediments in the coastal water. The
model-derived results revealed that the suspended sediment concentration
gradually decreased with increasing depth and distance from the shoreline.
Higher sediment concentrations accumulated at lower depths in coastal water
due to wave and current action that seasonally circulated the sediments. This
higher concentration of the suspended sediment load was estimated to be
0.92 mg L−1 at the shallow depths (<10 m) of the coastal waters and
0.30 mg L−1 at a depth of 30 m. Seasonal variability of suspended
sediments was observed in a north–south direction during the pre-monsoon;
the reverse was noted during the post-monsoon period. The spatial variability
of suspended sediments was indirectly proportional to the depth and distance
from the shoreline, and directly proportional to offshore wave and littoral
current activity. This study proves that the developed model coupled with the
provided computational algorithm can be used as an effective tool for the
estimation of suspended sediment concentrations using multi-temporal OLI
images; furthermore, the output may be helpful for coastal zone management
and conservation planning and development.
Constraints on Alpine Fault (New Zealand) mylonitization temperatures and the geothermal gradient from Ti-in-quartz thermobarometry
Authors: Kidder Steven B. , Toy Virginia G. , Prior David J. , Little Timothy A. , Khan Ashfaq , MacRae Colin 
Published: September 2018

Abstract. We constrain the thermal state of the central Alpine Fault using approximately 750 Ti-in-quartz secondary ion mass spectrometer (SIMS) analyses from a suite of variably deformed mylonites. Ti-in-quartz concentrations span more than 1 order of magnitude from 0.24 to  ∼ 5 ppm, suggesting recrystallization of quartz over a 300 °C range in temperature. Most Ti-in-quartz concentrations in mylonites, protomylonites, and the Alpine Schist protolith are between 2 and 4 ppm and do not vary as a function of grain size or bulk rock composition. Analyses of 30 large, inferred-remnant quartz grains ( > 250 µm) as well as late, crosscutting, chlorite-bearing quartz veins also reveal restricted Ti concentrations of 2–4 ppm. These results indicate that the vast majority of Alpine Fault mylonitization occurred within a restricted zone of pressure–temperature conditions where 2–4 ppm Ti-in-quartz concentrations are stable. This constrains the deep geothermal gradient from the Moho to about 8 km to a slope of 5 °C km−1. In contrast, the small grains (10–40 µm) in ultramylonites have lower Ti concentrations of 1–2 ppm, indicating a deviation from the deeper pressure–temperature trajectory during the latest phase of ductile deformation. These constraints suggest an abrupt, order of magnitude change in the geothermal gradient to an average of about 60 °C km−1 at depths shallower than about 8 km, i.e., within the seismogenic zone. Anomalously, the lowest-Ti quartz (0.24–0.7 ppm) occurs away from the fault in protomylonites, suggesting that the outer fault zone experienced minor plastic deformation late in the exhumation history when more fault-proximal parts of the fault were deforming exclusively by brittle processes.
Los derechos de ciudadanía de niños y adolescentes en un territorio singular: la trifrontera amazónica
Authors: Pineda Nebot Carmen , Pinheiro de Andrade Herbert Cristhiano , Almeida Olavo Antônio Vagner 
Published: September 2018

El objetivo de este artículo es analizar la situación general de la protección de los derechos y deberes de niños y adolescentes en Brasil, Colombia y Perú e identificar las acciones de protección de sus derechos en la triple frontera constituida por las ciudades de Tabatinga (BR), Leticia (CO) e Isla de Santa Rosa (PE). Esta investigación cualitativa ha analizado documentos y legislación relacionada con los derechos de los niños y adolescentes de los tres países, así como las páginas web de las tres ciudades. Además, fueran realizadas entrevistas en profundidad con los responsables de las acciones para niños y adolescentes en la trifrontera Amazónica. Ante la conquista legal de los derechos de ciudadanía de niños y adolescentes y de una realidad de vulnerabilidad social se señala que la protección de estos derechos debe afrontarse con acciones intersectoriales territoriales, sin embargo, en las ciudades investigadas predominan acciones estatales desarticuladas que no tienen en cuenta la especial situación territorial.
Concepciones hegemónicas de la infancia en un siglo de movimientos en favor del bienestar de la niñez
Authors: Tissera Luna Mara 
Published: September 2018

En las últimas décadas, las organizaciones no-gubernamentales internacionales y agencias internacionales han obtenido un papel hegemónico en la conceptualización de la infancia, y en la descripción y análisis de las problemáticas dignas de intervención en torno a ella. A pesar de la heterogeneidad de los orígenes y adscripciones de los actores que tuvieron incidencia en la conformación de los movimientos en favor de la niñez y de las diferentes conceptualizaciones de la infancia que defendían, la concepción de la infancia que devino hegemónica es aquella basada en el prototipo de niñez históricamente perteneciente a las clases burguesas de Europa y Norteamérica, basada en el carácter incompleto y dependiente de los niños y niñas, y en su cuidado y protección. En este artículo se expone una breve historización de los movimientos internacionales para la defensa de la niñez desde sus comienzos a principios del siglo XX, con el foco en los debates sobre las concepciones de niñez. En particular, nos centramos en la manera en la cual el desarrollo de los aparatos de intervención de los actores del humanitarismo y la cooperación internacional conllevó la legitimación de una concepción “universalizante” de la niñez, y de un enfoque para la planificación y desarrollo de las acciones globales a favor de la niñez basado en el cuidado y la protección de los niños.
Engineering Thermoplastics for Additive Manufacturing: A Critical Perspective with Experimental Evidence to Support Functional Applications
Authors: Cicala Gianluca , Latteri Alberta , Del Curto Barbara , Lo Russo Alessio , Recca Giuseppe , Farè Silvia 
Published: September 2018

Background Among additive manufacturing techniques, the filament-based technique involves what is referred to as fused deposition modeling (FDM). FDM materials are currently limited to a selected number of polymers. The present study focused on investigating the potential of using high-end engineering polymers in FDM. In addition, a critical review of the materials available on the market compared with those studied here was completed. Methods Different engineering thermoplastics, ranging from industrial grade polycarbonates to novel polyetheretherketones (PEEKs), were processed by FDM. Prior to this, for innovative filaments based on PEEK, extrusion processing was carried out. Mechanical properties (i.e., tensile and flexural) were investigated for each extruded material. An industrial-type FDM machine (Stratasys Fortus® 400 mc) was used to fully characterize the effect of printing parameters on the mechanical properties of polycarbonate. The obtained properties were compared with samples obtained by injection molding. Finally, FDM samples made of PEEK were also characterized and compared with those obtained by injection molding. Results The effect of raster to raster air gap and raster angle on tensile and flexural properties of printed PC was evidenced; the potential of PEEK filaments, as novel FDM material, was highlighted in comparison to state of the art materials. Conclusions Comparison with injection molded parts allowed to better understand FDM potential for functional applications. The study discussed pros and cons of the different materials. Finally, the development of novel PEEK filaments achieved important results offering a novel solution to the market when high mechanical and thermal properties are required.