782 research outputs found
Ground Motion Prediction Equations Derived from the Italian Strong Motion Database
We present a set of ground motion prediction equations (GMPEs) derived for
the geometrical mean of the horizontal components and the vertical, considering the latest
release of the strong motion database for Italy. The regressions are performed over the magnitude
range 4–6.9 and considering distances up to 200 km. The equations are derived for peak
ground acceleration (PGA), peak ground velocity (PGV) and 5%-damped spectral acceleration
at periods between 0.04 and 2 s. The total standard deviation (sigma) varies between
0.34 and 0.38 log10 unit, confirming the large variability of ground shaking parameters when
regional data sets containing small to moderate magnitude events (M < 6) are used. The
between-stations variability provides the largest values for periods shorter than 0.2 s while,
for longer periods, the between-events and between-stations distributions of error provide
similar contribution to the total variabilit
Bacterial community structure and removal performances in IFAS-MBRs: A pilot plant case study
The paper reports the results of an experimental campaign carried out on a University of Cape Town (UCT) integrated fixed-film activated sludge (IFAS) membrane bioreactor (MBR) pilot plant. The pilot plant was analysed in terms of chemical oxygen demand (COD) and nutrients removal, kinetic/stoichiometric parameters, membrane fouling and sludge dewaterability. Moreover, the cultivable bacterial community structure was also analysed. The pilot plant showed excellent COD removal efficiency throughout experiments, with average value higher than 98%, despite the slight variations of the influent wastewater. The achieved nitrification efficiency was close to 98% for most of the experiments, suggesting that the biofilm in the aerobic compartment might have sustained the complete nitrification of the influent ammonia, even for concentrations higher than 100\ua0mg\ua0L-1. The irreversible resistance due to superficial cake deposition was the mechanism that mostly affected the membrane fouling. Moreover, it was noticed an increase of the resistance due pore blocking likely due to the increase of the EPSBound fraction that could derive by biofilm detachment. The bacterial strains isolated from aerobic tank are wastewater bacteria known for exhibiting efficient heterotrophic nitrification\ue2\u80\u93aerobic denitrification and producing biofilm
Pan-European ground-motion prediction equations for the average horizontal component of PGA, PGV, and 5 %-damped PSA at spectral periods up to 3.0 s using the RESORCE dataset
This article presents a set of Ground-Motion Prediction Equations (GMPEs) for Europe and the Middle East, derived from the RESORCE strong motion data bank, following a standard regression approach. The parametric GMPEs are derived for the peak ground acceleration, peak ground velocity, and 5 %-damped pseudo-absolute acceleration response spectra computed over 23 periods between 0.02 and 3 s, considering the average horizontal-component ground-motions. The GMPEs are valid for distances less than 300 km, hypocentral depth up to 35 km and over the magnitude range 4–7.6. Two metrics for the source-to-station distance (i.e. Joyner-Boore and hypocentral) are considered. The selected dataset is composed by 2,126 recordings (at a period of 0.1 s) related to 365 earthquakes, that includes strong-motion data from 697 stations.The EC8 soil classification (four classes from A to D) discriminates recording sites and four classes (normal, reverse, strike-slip, and unspecified) describe the style of faulting. A subset which contains only stations with measured Vs30 and earthquakes with specified focal mechanism (1,224 records from 345 stations and 255 earthquakes) is used to test of the accuracy of the median prediction and the variability associated to the broader data set. A random effect regression scheme is applied and bootstrap analyses are performed to estimate the 95 % confidence levels for the parameters. The total standard deviation sigma is decomposed into between-events and within-event components, and the site-to-site component is evaluated as well. The results show that the largest contribution to the total sigma is coming from the within-event component. When analyzing the residual distributions, no significant trends are observed that can be ascribed to the earthquake type (mainshock-aftershock classification) or to the non-linear site effects. The proposed GMPEs have lower median values than global models at short periods and large distances, while are consistent with global models at long periods (T>1) s. Consistency is found with two regional models developed for Turkey and Italy, as the considered dataset is dominated by waveforms recorded in these regions
Developing keratin sponges with tunable morphologies and controlled antioxidant properties induced by doping with polydopamine (PDA) nanoparticles
his work investigates the preparation of wool keratin sponges by freeze-drying procedure starting form keratin aqueous solutions. The study highlights the correlations between process parameters (protein concentration and freezing rate) and the chemical-physical properties of the final sponges.
In particular, as the keratin concentration increases from 1 to 20% wt, the mean pore size and the porosity decrease from 62 to 37 mu m and from 94 to 50% respectively, while the chemical stability in physiological conditions increases, as well as the thermal stability and the elastic modulus. On the other hand, the increase of the freezing rate affects the design of sponges that appear as stacked leaflets structures with oriented pores.
Moreover, in order to confer to keratin sponges antioxidant properties, polydopamine (PDA) nanoparticles were used as fillers. To this end, PDA nanoparticles of about 130 nm were successfully dispersed in the sponges, bestowing time-dependent anti-oxidant properties on the scaffolds, with no significant modification of sponges morphological structure as well as reduction of the thermal stability and mechanical behaviour
Time-Dependent Density-Functional Theory for Trapped Strongly-Interacting Fermionic Atoms
The dynamics of strongly interacting trapped dilute Fermi gases (dilute in
the sense that the range of interatomic potential is small compared with
inter-particle spacing) is investigated in a single-equation approach to the
time-dependent density-functional theory. Our results are in good agreement
with recent experimental data in the BCS-BEC crossover regime. It is also shown
that the calculated corrections to the hydrodynamic approximation may be
important even for systems with a rather large number of atoms.Comment: Resubmitted to PRA in response to referee's comments. Abstract is
changed. Added new figure
Measurement of the 20 and 90 keV resonances in the N reaction via THM
The reaction is of primary importance in
several astrophysical scenarios, including fluorine nucleosynthesis inside AGB
stars as well as oxygen and nitrogen isotopic ratios in meteorite grains. Thus
the indirect measurement of the low energy region of the reaction has been performed to reduce the nuclear
uncertainty on theoretical predictions. In particular the strength of the 20
and 90 keV resonances have been deduced and the change in the reaction rate
evaluated.Comment: 4 pages, 4 figures, submitted to PR
Biochar powders coating to improve evaporative cooling in Maisotsenko-cycle systems
This work presents an experimental study on the performance of biochar powder coatings on aluminum surfaces for use in indirect evaporative coolers based on the Maisotsenko cycle. The performance of the biochar coated samples was compared to cellulose-coated aluminum samples and uncoated ones. Results showed that biochar coatings improved the performance of uncoated aluminum, with the 150 ÎĽm particle size coating offering performance comparable to cellulose. However, wetting times were longer, which has implications for spraying strategies
INGV strong-motion data web-portal: a focus on the Emilia seismic sequence of May-June 2012
In Italy, strong-motion monitoring was started in 1972
by different Institutions, although mainly through Ente
Nazionale per l'Energia Elettrica (ENEL; Italian National
Electricity Company) and Dipartimento della Protezione
Civile (DPC; Italian Department of Civil Protection), with
different purposes. These included permanent acceleromet-
ric monitoring and temporary monitoring during seismic se-
quences or before permanent installation. Today, the
National Accelerometric Network (RAN; Rete Accelero-
metrica Nazionale) [Gorini et al. 2010, Zambonelli et al.
2011] is operated by the DPC and consists of 464 digital sta-
tions. These are distributed throughout the whole national
territory, with a prevalence for areas of major seismicity.
In 2006, the INGV began strong-motion monitoring, by
installing 22 accelerometric stations in northern Italy (RAIS;
Rete Accelerometrica Italia Settentrionale; Accelerometric
Network of Northern Italy; http://rais.mi.ingv.it/). In 2008,
the monitoring was extended to a national scale: this effort
led to the installation of 105 accelerometers, collocated with
the velocimetric sensors, in selected Rete Sismica Nazionale
(RSN; National Seismic Network) sites [Amato and Mele
2008] that are managed by the Centro Nazionale Terremoti
(CNT; National Earthquake Centre). Overall, the 127 strong-
motion stations that form the INGV Italian strong-motion
network homogeneously cover the whole Italian territory.
The progress achieved in Italy in the field of strong-mo-
tion monitoring and strong-motion data archiving and dis-
semination was illustrated in a recently published special
issue of the Bulletin of Earthquake Engineering [Luzi et al.
2010]. The strong-motion data recorded by the RAN have
been distributed and are available on request to the DPC and
to the Italian Accelerometric Archive (ITACA), as the Italian
strong-motion database (http://itaca.mi.ingv.it/) [Pacor et
al. 2011a], which has been updated with records to 2009. The
INGV strong-motion data are archived in real-time and dis-
tributed through the European Integrated Data Archive
(EIDA; http://eida.rm.ingv.it/) web portal.
Recently, an INGV working group developed the first
version of a web portal with the aim of archiving, processing
and distributing accelerometric data recorded by permanent
and temporary INGV stations. This web portal (www.mi.
ingv.it/ISMD/; Figure 1, top panel) is composed of two main
modules: the former is known as the INGV Strong Motion
Data (ISMD, www.mi.ingv.it/ISMD/ismd.h
tml/; Figure 1,
bottom left panel) and has as its main scope the analyse and
distribution in quasi-real time (a few hours after event oc-
currence) of the uncorrected accelerometric data, and the
related metadata obtained after an automatic processing pro-
cedure. This latter, known as the Dynamic Archive (DYNA,
http://dyna.mi.ingv.it/DYNA-archive/; Figure 1, bottom
right panel) is a dynamic database where manually post-
processed accelerometric waveforms are provided, together
with their metadata. Both of these archives are designed and
structured in such a way that their compilations and updat-
ing will be almost completely automatic.
At the end of May 2012, a first prototype of the ISMD
module was published, providing the uncorrected strong-
motion data recorded by the INGV stations for the main
events of the Emilia seismic sequence [Massa et al. 2012]
Strong-motion parameters of the Mw=6.3 Abruzzo (Central Italy) earthquake
INGVPublished1.1. TTC - Monitoraggio sismico del territorio nazionaleope
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