Search results for "GC"

Un tesoretto dimenticato da Himera: Nuovi dati sul ripostiglio IGCH 2258

2022

Due to the troubled events that accompanied its discovery, the hoard IGCH 2258 has been neglected by scientific studies. The recent examination conducted at the Coin Cabinet of the Museum “A. Salinas "in Palermo, where the complex is kept, and the analysis of the archive documentation of the Museum and Central Archives of the State of Rome allowed to clarify the composition of the complex and to provide more precise information on the place of discovery, allowing to exploit the informative potential of this hoard.

L’INNOVAZIONE DEL CAPABILITY APPROACH NEL PROMUOVERE LA COMPETENZA DIGITALE DEGLI INSEGNANTI DELLA SCUOLA SECONDARIA

2022

Le questioni legate alla digitalizzazione e allo sviluppo dei media richiedono un'attenta analisi - in una duplice direzione - su quanto sia importante agire in modo da 1) accrescere le competenze della persona che si trova in un mondo complesso ed estremamente eterogeneo in termini di bisogni, caratteristiche e prospettive di vita; 2) sviluppare un contesto in grado di offrire opportunità formative ai docenti, con particolare riguardo ai docenti oggigiorno, chiamati ad un'opera di mediazione comunicativa e didattica per colmare le tante distanze acuite dall'attuale Covid 19 emergenza pandemia. Per le sue caratteristiche intrinseche, il Capability Approach è un approccio multidimensionale c…

The organic carbon derived from sewage sludge as a key parameter determining the fate of trace metals.

2007

8 pages; International audience; In a sandy agricultural soil of south-west of France, continuously cultivated with maize and amended with sewage-sludge over 20 years, the behavior of three trace metals (Cu, Pb, and Zn) was studied during the sludge applications (1974-1993) and after its cessation (1993-1998). Using the delta13C analysis, the dynamics of different sources of organic matter were followed in order to elucidate the influence of the sludge-derived organic matter on the fate of trace metals in the soil and its particle size fractions. This study revealed that sludge-derived organic matter contributed to the formation of macroaggregates through the binding of preexisting microagg…

La gangrena

2003

Long-term effects of metal-containing farmyard manure and sewage sludge on soil organic matter in a fluvisol

2005

Abstract Our aim was to establish the long-term effects of repeated applications after 20 y of organic amendments (farmyard manure at 10 t ha −1  y −1 , and urban sewage sludge at two different rates, 10 t ha −1  y −1 and 100 t ha −1 every 2 y) on the quality of a sandy and poorly buffered soil (Fluvisol, pH 6). Chemical characteristics and biodegradability of the labile organic matter, which is mainly derived from microbial biomass and biodegradation products of organic residues, were chosen as indicators for soil quality. The organic C content had reached a maximal value (30.6 g C kg −1 in the 100 t sludge-treated soil), i.e. about 2.5 times that in the control. Six years after the last a…

Volatile profiles of Sicilian prickly pear (Opuntia ficus indica) by SPME-GC/MS analysis

2005

The aroma compounds present in the headspace of homogenized slurries of fresh prickly pears (Opuntia ficus-indica) from Sicilian cultivars were determined. Solid Phase Microextraction (SPME) followed by Gas-chromatography/Mass Spectrometry (GC/MS) analysis was used to characterize the volatile compounds. The volatile flavour profiles of the three cultivars investigated (red, white and yellow) showed significant differences. The aromatic profile of peeled prickly pears stored for one day was different from the one of the fresh samples, mainly due to the occurrence of some oxidative and hydrolytic reactions

Selection of sampling adsorbents and optimisation and validation of a GC-MS/MS method for airborne pesticides

2017

ABSTRACTA methodology for the sampling and determination of airborne pesticides has been developed. The trapping efficiency of three adsorbents, namely XAD-2,XAD-4 and a sandwich sorbent (PUF-XAD2-PUF), was tested for 34 pesticides and the latter was selected because it presented the highest retention capacity without breakthrough. Pesticides were determined by gas chromatography coupled to an ion trap mass spectrometer in tandem. The method showed recoveries ranging from 70% to 120% with limits of quantification in the range of 16.1–322.6 pg m−3 when 155 m3 were sampled. This analytical strategy was applied to 10 indoor air samples collected in dwellings from the Valencian Region. Six pest…

Chromatographic Air Analyzer Microsystem for the Selective and Sensitive Detection of Explosive-related Compounds

2014

Abstract The detection of explosives and explosive-related compounds is of major importance for the monitoring of explosive- contaminated sites. Current methods need to become cheaper and portable while maintaining a high sensitivity and selectivity level. In that sense, a silicon micro-analytical platform consisting of a three-dimensional micro-preconcentrator based on a hydrophobic zeolite, coupled to a silicon spiral micro-column was built. A chemical gas sensor acted as a miniaturized gas detector. This system allowed selective detection of orthonitrotoluene (ONT), an explosive-related compound at the sub-ppm level in the presence of toluene and moisture.

Chemical composition of the essential oil from aerial parts of Stachys palustris L. (Lamiaceae) growing wild in Southern Italy

2007

The paper reports the composition of the essential oil from aerial parts of Stachys palustris L. (Lamiaceae) from Southern Italy. The essential oil was extracted by hydrodistillation from selected plants and its chemical composition was determined by the GC-MS system on two fused- silica capillary columns of different polarity. The mass fraction of oil was 0.21 % on a dry weight basis. Altogether, 92 compounds were identified accounting for 93.6 % of the total oil, which was characterized mainly by carbonylic compounds (25.4 %), fatty acids and their esters (24.2 %), along with sesquiterpenoidic compounds (16.0 %) and phenols (11.2 %). The major components of the sample were caryophyllene o…

Mapping accretion and its variability in the young open cluster NGC 2264: A study based on u-band photometry

2014

We aim at characterizing the accretion properties of several hundred members of the star-forming cluster NGC 2264 (3 Myr). We performed a deep u,g,r,i mapping and a simultaneous u+r monitoring of the region with CFHT/MegaCam in order to directly probe the accretion process from UV excess measurements. Photometric properties and stellar parameters are determined homogeneously for about 750 monitored young objects, spanning the mass range 0.1-2 Mo. About 40% are classical (accreting) T Tauri stars, based on various diagnostics (H_alpha, UV and IR excesses). The remaining non-accreting members define the (photospheric+chromospheric) reference UV emission level over which flux excess is detecte…