2,184 research outputs found
An innovative, fast and facile soft-template approach for the fabrication of porous PDMS for oil-water separation
Oil wastewater and spilled oil caused serious environmental pollution and
damage to public health in the last years. Therefore, considerable efforts are
made to develop sorbent materials able to separate oil from water with high
selectivity and sorption capacity. However most of them are low reusable, with
low volume absorption capacity and poor mechanical properties. Moreover, the
synthesis is time-consuming, complex and expensive limiting its practical
application in case of emergency. Here we propose an innovative approach for
the fabrication of porous PDMS starting from an inverse water-in-silicone
procedure able to selectively collect oil from water in few seconds. The
synthesis is dramatically faster than previous approaches, permitting the
fabrication of the material in few minutes independently from the dimension of
the sponges. The porous material evidenced a higher volume sorption capacity
with respect to other materials already proposed for oil sorption from water
and excellent mechanical and reusability properties.This innovative fast and
simple approach can be successful in case of emergency, as oil spill accidents,
permitting in situ fabrication of porous absorbents
The NASA-Ames Research Center stratospheric aerosol model. 2. Sensitivity studies and comparison with observatories
Sensitivity tests were performed on a one-dimensional, physical-chemical model of the unperturbed stratospheric aerosols, and model calculations were compared with observations. The tests and comparisons suggest that coagulation controls the particle number mixing ratio, although the number of condensation nuclei at the tropopause and the diffusion coefficient at high altitudes are also important. The sulfur gas source strength and the aerosol residence time are much more important than the supply of condensation nuclei in establishing mass and large particle concentrations. The particle size is also controlled mainly by gas supply and residence time. In situ observations of the aerosols and laboratory measurements of aerosols, parameters that can provide further information about the physics and chemistry of the stratosphere and the aerosols found there are provided
An assessment of the effect of supersonic aircraft operations on the stratospheric ozone content
An assessment of the potential effect on stratospheric ozone of an advanced supersonic transport operations is presented. This assessment, which was undertaken because of NASA's desire for an up-to-date evaluation to guide programs for the development of supersonic technology and improved aircraft engine designs, uses the most recent chemical reaction rate data. From the results of the present assessment it would appear that realistic fleet sizes should not cause concern with regard to the depletion of the total ozone overburden. For example, the NOx emission of one type designed to cruise at 20 km altitude will cause the ozone overburden to increase by 0.03% to 0.12%, depending upon which vertical transport is used. These ozone changes can be compared with the predictions of a 1.74% ozone decrease (for 100 Large SST's flying at 20 km) made in 1974 by the FAA's Climatic Impact Assessment Program
The NASA-AMES Research Center Stratospheric Aerosol Model. 1. Physical Processes and Computational Analogs
A time-dependent one-dimensional model of the stratospheric sulfate aerosol layer is presented. In constructing the model, a wide range of basic physical and chemical processes are incorporated in order to avoid predetermining or biasing the model predictions. The simulation, which extends from the surface to an altitude of 58 km, includes the troposphere as a source of gases and condensation nuclei and as a sink for aerosol droplets. The size distribution of aerosol particles is resolved into 25 categories with particle radii increasing geometrically from 0.01 to 2.56 microns such that particle volume doubles between categories
When contrasting polarity, the Dutch use particles, Germans intonation
This study compares how Dutch and German, two closely related languages, signal a shift from a negative to a positive polarity in two contexts, when contrasting the polarity relative to a different topic situation (In my picture the man washes the car following after In my picture the man does not wash the car, henceforth polarity contrast) and when correcting the polarity of a proposition (The man washes the car following after The man does not wash the car, henceforth polarity correction). Production data show that in both contexts German speakers produced Verum focus (i.e., a high-falling pitch accent on the finite verb), while Dutch speakers mostly used the accented affirmative particle wel. This shows that even lexically and syntactically close languages behave differently when it comes to signalling certain pragmatic functions. Furthermore, we found that in polarity correction contexts, both affirmative particles and Verum focus were realized with stronger prosodic prominence. This difference was found in both languages and might be due to a secondary (syntagmatic) effect of the information structure of the utterance (absence or presence of a contrastive topic)
On the key role of droughts in the dynamics of summer fires in Mediterranean Europe
Summer fires frequently rage across Mediterranean Europe, often intensified by high temperatures and droughts. According to the state-of-the-art regional fire risk projections, in forthcoming decades climate effects are expected to become stronger and possibly overcome fire prevention efforts. However, significant uncertainties exist and the direct effect of climate change in regulating fuel moisture (e.g. warmer conditions increasing fuel dryness) could be counterbalanced by the indirect effects on fuel structure (e.g. warmer conditions limiting fuel amount), affecting the transition between climate-driven and fuel-limited fire regimes as temperatures increase. Here we analyse and model the impact of coincident drought and antecedent wet conditions (proxy for the climatic factor influencing total fuel and fine fuel structure) on the summer Burned Area (BA) across all eco-regions in Mediterranean Europe. This approach allows BA to be linked to the key drivers of fire in the region. We show a statistically significant relationship between fire and same-summer droughts in most regions, while antecedent climate conditions play a relatively minor role, except in few specific eco-regions. The presented models for individual eco-regions provide insights on the impacts of climate variability on BA, and appear to be promising for developing a seasonal forecast system supporting fire management strategies.We thank the European Forest Fire Information System-EFFIS (http://effis.jrc.ec.europa.eu) of the European
Commission Joint Research Centre for the fire data. We acknowledge the SPEI data providers (http://sac.csic.
es/spei/database.html). Special thanks to Joaquín Bedia, Esteve Canyameras, Xavier Castro and Andrej Ceglar
for helpful discussions on the study. This work was partially funded by the Project of Interest “NextData” of the Italian Ministry for Education, University and Research and by the EU H2020 Project 641762 “ECOPOTENTIAL: Improving Future Ecosystem Benefits through Earth Observations”. Ricardo Trigo was supported by IMDROFLOOD funded by Portuguese FCT (WaterJPI/0004/2014).Peer ReviewedPostprint (published version
Intonational means to mark verum focus in German and French
German and French differ in a number of aspects. Regarding the prosody-pragmatics interface, German is said to have a direct focus-to-accent mapping, which is largely absent in French – owing to strong structural constraints. We used a semi-spontaneous dialogue setting to investigate the intonational marking of Verum Focus, a focus on the polarity of an utterance in the two languages (e.g. the child IS tearing the banknote as an opposite claim to the child is not tearing the banknote). When Verum Focus applies to auxiliaries, pragmatic aspects (i.e. highlighting the contrast) directly compete with structural constraints (e.g. avoiding an accent on phonologically weak elements such as monosyllabic function words). Intonational analyses showed that auxiliaries were predominantly accented in German, as expected. Interestingly, we found a high number of (as yet undocumented) focal accents on phrase-initial auxiliaries in French Verum Focus contexts. When French accent patterns were equally distributed across information structural contexts, relative prominence (in terms of peak height) between initial and final accents was shifted towards initial accents in Verum Focus compared to non-Verum Focus contexts. Our data hence suggest that French also may mark Verum Focus by focal accents but that this tendency is partly overridden by strong structural constraints
Environmental effects of SPS: The middle atmosphere
The heavy lift launch vehicle associated with the solar power satellite (SPS) would deposit in the upper atmosphere exhaust and reentry products which could modify the composition of the stratosphere, mesosphere, and lower ionosphere. In order to assess such effects, atmospheric model simulations were performed, especially considering a geographic zone centered at the launch and reentry latitudes
THE VALUE OF KNOWLEDGE THROUGH H-BIM MODELS: HISTORIC DOCUMENTATION WITH A SEMANTIC APPROACH
Abstract. The Building Information Modeling (BIM) in the Architectural Heritage field is constantly proving to be a fertile ground for the experimentation of innovative systems for the enhancement and management of cultural heritage. Regarding to the management of the entire process, the building field is increasing in efficiency from the construction to the management phase; conversely, the approach to historical buildings opens up interesting and heterogeneous scenarios, according to different levels of complexity. The presented work is the result of a collaboration between the Politecnico di Torino and the Escuela Técnica Superior de Arquitectura of Granada: the main scope was to create an historic building information model (H-BIM) of the building that today hosts the Faculty of Architecture (ETSAG), taking into account its historical past from the sixteenth century up to the present day, as the result of many modifications, extensions and different use classifications over time. According to this, the BIM methodology can be considered as a bridge between the archive documentation and the digital model, proving to be an effective tool as a data repository, semantically oriented, not only constituted by geometry, but also by alpha-numerical attributes, improving in effectiveness if it is directly related to formal language object oriented.</p
Stratospheric aerosol modification by supersonic transport operations with climate implications
The potential effects on stratospheric aerosois of supersonic transport emissions of sulfur dioxide gas and submicron size soot granules are estimated. An interactive particle-gas model of the stratospheric aerosol is used to compute particle changes due to exhaust emissions, and an accurate radiation transport model is used to compute the attendant surface temperature changes. It is shown that a fleet of several hundred supersonic aircraft, operating daily at 20 km, could produce about a 20% increase in the concentration of large particles in the stratosphere. Aerosol increases of this magnitude would reduce the global surface temperature by less than 0.01 K
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