682 research outputs found
Applicazioni della valenza riflessiva dello European Language Portfolio
Nell’anno accademico 2004-05 il Centro Linguistico dell’Università di Trieste
ha avviato un esperimento sul Portfolio Europeo delle Lingue utilizzando la
traduzione italiana AICLU della versione del CercleS per studenti universitari.
In quest’articolo verranno illustrati alcuni presupposti teorici dell’autovalutazione
e della riflessione, le fasi iniziali dell’esperimento svolto con un gruppo
di studenti della FacoltĂ di Scienze della Formazione, e infine, i problemi
traduttivi incontrati nella trasposizione del European Language Portfolio (ELP)
dall’inglese all’italiano
Velocity-dependent quantum phase slips in 1D atomic superfluids
Quantum phase slips are the primary excitations in one-dimensional
superfluids and superconductors at low temperatures but their existence in
ultracold quantum gases has not been demonstrated yet. We now study
experimentally the nucleation rate of phase slips in one-dimensional
superfluids realized with ultracold quantum gases, owing along a periodic
potential. We observe a crossover between a regime of temperature-dependent
dissipation at small velocity and interaction and a second regime of
velocity-dependent dissipation at larger velocity and interaction. This
behavior is consistent with the predicted crossover from thermally-assisted
quantum phase slips to purely quantum phase slips.Comment: 7 pages, 6 figure
Diurnal and semidiurnal cyclicity of Radon (222Rn) in groundwater, Giardino Spring, Central Apennines, Italy
Understanding natural variations of Rn (222Rn) concentrations is the fundamental
prerequisite of using this radioactive gas as a tracer, or even precursor, of natural processes, including
earthquakes. In this work, Rn concentrations in groundwater were continuously measured over
a seven-month period, during 2017, in the Giardino Spring, Italy, together with groundwater levels
in a nearby well installed into a fractured regional aquifer. Data were processed to reduce noise,
and then analyzed to produce the Fourier spectra of Rn concentrations and groundwater levels.
These spectra were compared with the spectrum of tidal forces. Results showed that diurnal and
semidiurnal cycles of Rn concentrations, and filtered oscillations of groundwater levels, in the nearby
well, are correlated with solar and luni-solar components of tidal forces, and suggested no correlation
with the principal lunar components. Therefore, influencing factors linked to solar cycles, such as
daily oscillations of temperature and atmospheric pressure, and related rock deformations, may have
played a role in Rn concentrations and groundwater levels. An open question remains regarding the
correlation, which is documented elsewhere, of Rn concentrations and groundwater levels with the
lunar components of the solid Earth tides
Degradation of Film and Rigid Bioplastics During the Thermophilic Phase and the Maturation Phase of Simulated Composting
AbstractThe recent regulations, which impose limits on single use plastics and packaging, are encouraging the development of bioplastics market. Some bioplastics are labelled as compostable with the organic waste according to a specific certification (EN 13432), however the conditions of industrial composting plants are generally less favourable than the standard test conditions. Aiming at studying the effective degradation of marketable bioplastic products under composting, the current research stresses novel elements which can strongly influence bioplastics degradation: the simulation of industrial composting conditions and the thickness of bioplastic products, ranging between 50 and 500 µm. The research approaches these critical aspects simulating a composting test of 20 days of thermophilic phase followed by 40 days of maturation phase, on starch-based polymer Mater-Bi® (MB), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA) of different thickness. Conventional low density polyethylene (LDPE) was introduced as negative control. An overall study with Fourier Transform InfraRed (FTIR), ThermoGravimetric Analysis (TGA), Gel Permeation Chromatography (GPC), Scanning Electron Microscope (SEM) and visual inspections was applied. Results highlighted that MB film presented the highest degradation rate, 45 ± 4.7% in terms of weight loss. Both MB and PBAT were subjected to physico-chemical features change, while LDPE presented slight degradation signs. The most critical observations have been done for PLA, which is strongly influenced both by thickness and thermophilic phase duration, shorter than the EN 13432 conditions
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