2,328 research outputs found
Applications of biopolymers to processes of environmental control
Two new methods of insolubilizing in cellulose triacetate membranes, natural or synthetic polyelectrolytes, able to bind heavy metal ions, were experimented and discussed. The efficiency of the obtained membranes was tested by monitoring the cupric ion adsorption with a copper ion selective electrode (ISE
A meteorologicalâhydrological regional ensemble forecast for an early-warning system over small Apennine catchments in Central Italy
Abstract. The weather forecasts for precipitation have considerably improved in recent years thanks to the increase of computational power.
This allows for the use of both a higher spatial resolution and the parameterization schemes specifically developed for representing sub-grid scale physical processes at high resolution. However, precipitation estimation is still affected by errors that can impact the response of hydrological models. To the aim of improving the hydrological forecast and the characterization of related uncertainties, a regional-scale meteorologicalâhydrological ensemble is presented. The uncertainties in the precipitation forecast and how they propagate in the hydrological model are also investigated. A meteorologicalâhydrological offline coupled ensemble is built to forecast events in a complex-orography terrain where catchments of different sizes are present. The Best Discharge-based Drainage (BDD; both deterministic and probabilistic) index, is defined with the aim of forecasting hydrological-stress conditions and related uncertainty.
In this context, the meteorologicalâhydrological ensemble forecast is implemented and tested for a severe hydrological event which occurred over Central Italy on 15 November 2017, when a flood hit the Abruzzo region with precipitation reaching 200âmmâ(24âh)â1 and producing damages with a high impact on social and economic activities. The newly developed meteorologicalâhydrological ensemble is compared with a high-resolution deterministic forecast and with the observations (rain gauges and radar data) over the same area. The receiver operating characteristic (ROC) statistical indicator shows how skilful the ensemble precipitation forecast is with respect to both rain-gauge- and radar-retrieved precipitation. Moreover, both the deterministic and probabilistic configurations of the BDD index are compared with the alert map issued by Civil Protection Department for the event showing a very good agreement.
Finally, the meteorologicalâhydrological ensemble allows for an estimation of both the predictability of the event a few days in advance and the uncertainty of the flood. Although the modelling framework is implemented on the basins of the Abruzzo region, it is portable and applicable to other areas
A cost-effective algorithm for the solution of engineering problems with particle swarm optimization
Biogeography of cyanobacteria in lakes and rivers based on taxonomic and functional trait approaches: results of a wide high throughput sequencing survey in the alpine region.
Spallative ablation of dielectrics by X-ray laser
Short laser pulse in wide range of wavelengths, from infrared to X-ray,
disturbs electron-ion equilibrium and rises pressure in a heated layer. The
case where pulse duration is shorter than acoustic relaxation time
is considered in the paper. It is shown that this short pulse may cause
thermomechanical phenomena such as spallative ablation regardless to
wavelength. While the physics of electron-ion relaxation on wavelength and
various electron spectra of substances: there are spectra with an energy gap in
semiconductors and dielectrics opposed to gapless continuous spectra in metals.
The paper describes entire sequence of thermomechanical processes from
expansion, nucleation, foaming, and nanostructuring to spallation with
particular attention to spallation by X-ray pulse
Assessing the suitability of a range of benthic indices in the evaluation of environmental impact of fin and shellfish aquaculture located in sites across Europe
The European Union-funded ECASA project (Ecosystem Approach for Sustainable Aquaculture) studied the
impacts from aquaculture on ecosystems from northern Norway to Greece. The objectives of this investigation
were to identify quantitative indicators of the effects of aquaculture on marine communities, and to assess their
applicability over a range of ecosystems and aquaculture production systems. The study included 6 Mediterranean
and 4 Atlantic sites, 7 ofwhich produced finfish (seabream, seabass, tuna, salmon and cod), and 2 bivalve molluscs
(oysters, mussels, and clams); one site produced both fish and bivalves. Cultivation methods included finfish
cages, long-lines and trestles. Similar sampling methodologies were employed at the 10 study sites, obtaining
sediment, hydrodynamic, and benthic faunal data. The horizontal impact from organic enrichment extended 50m
from the farms, with contradictory responses in several indicators (individual abundance, biomass) and a more
consistent response of the Infaunal Trophic Index (ITI) and AZTI'sMarine Biotic Index (AMBI). By means of Partial
Redundancy Analysis, it was demonstrated that the environmental variables explained 53.2% of the variability in
the macrofaunal variables (individual abundance, species richness, diversity, AMBI and ITI), whilst the explained
variance was partialled out within three groups of variables: (i) âhydrographyâ (depth, distance to farm, average
current speed), which explained 11.5% of the variance; (ii) âsedimentâ (Eh and percentages of silt and total organic
matter), which explained 5.4%; and (iii) âcagesâ (years of production and annual production), which explained
15.2%. The shared variance explained by interactions among these groups was 21.1%. These results, together with
multiple regression analysis, provide an accurate assessment of the degree of impact from aquaculture. In
conclusion, the use of several benthic indicators, in assessing farm impacts, together with the investigation of
dynamics of the studied location, water depth, years of farm activity, and total annual production, must be
included when interpreting the response of benthic communities to organic enrichment from aquaculture
ACCURATE WAVELENGTH MEASUREMENTS AND MODELING OF Fe XV TO Fe XIX SPECTRA RECORDED IN HIGH-DENSITY PLASMAS BETWEEN 13.5 AND 17 A
Iron spectra have been recorded from plasmas created at three different laser plasma facilities: the Tor Vergata University laser in Rome (Italy), the Hercules laser at ENEA in Frascati (Italy), and the Compact Multipulse Terawatt (COMET) laser at LLNL in California (USA). The measurements provide a means of identifying dielectronic satellite lines from Fe XVI and Fe XV in the vicinity of the strong 2p â 3d transitions of Fe XVII. About 80 În â„ 1 lines of Fe XV (Mg-like) to Fe XIX (O-like) were recorded between 13.8 and 17.1 A with a high spectral resolution (λ/Îλ â 4000); about 30 of these lines are from Fe XVI and Fe XV. The laser-produced plasmas had electron temperatures between 100 and 500 eV and electron densities between 1020 and 1022 cm-3. The Hebrew University Lawrence Livermore Atomic Code (HULLAC) was used to calculate the atomic structure and atomic rates for Fe XV-XIX. HULLAC was used to calculate synthetic line intensities at Te = 200 eV and ne = 1021 cm-3 for three different conditions to illustrate the role of opacity: optically thin plasmas with no excitation-autoionization/dielectronic recombination (EA/DR) contributions to the line intensities, optically thin plasmas that included EA/DR contributions to the line intensities, and optically thick plasmas (optical depth â200 ÎŒm) that included EA/DR contributions to the line intensities. The optically thick simulation best reproduced the recorded spectrum from the Hercules laser. However, some discrepancies between the modeling and the recorded spectra remain
Correction to: High precision particle astrophysics as a new window on the universe with an Antimatter Large Acceptance Detector In Orbit (ALADInO)
High precision particle astrophysics as a new window on the universe with an Antimatter Large Acceptance Detector In Orbit (ALADInO)
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