Search results for "COPI"

Accretion in young stars: measure of the stream velocity of TW Hya from the X-ray Doppler shift

2015

High-resolution X-ray spectra are a unique tool to investigate the accretion process in young stars. In fact X-rays allow to investigate the accretion-shock region, where the infalling material is heated by strong shocks due to the impact with the denser stellar atmosphere. Here we show for the first time that it is possible to constrain the velocity of the accretion stream by measuring the Doppler shift of the emitted X-rays. To this aim we analyzed the deep Chandra/HETGS observation of the accreting young star TW Hya. We selected a sample of emission lines free from significant blends, fitted them with gaussian profiles, computed the radial velocity corresponding to each line, and average…

Multiwavelength diagnostics of accretion in an X-ray selected sample of CTTSs

2011

Context. High resolution X-ray spectroscopy has revealed soft X-rays from high density plasma in classical T Tauri stars (CTTSs), probably arising from the accretion shock region. However, the mass accretion rates derived from the X-ray observations are consistently lower than those derived from UV/optical/NIR studies. Aims: We aim to test the hypothesis that the high density soft X-ray emission originates from accretion by analysing, in a homogeneous manner, optical accretion indicators for an X-ray selected sample of CTTSs. Methods: We analyse optical spectra of the X-ray selected sample of CTTSs and calculate the accretion rates based on measuring the Hα, Hβ, Hγ, He ii 4686 Å, He i 5016 …

High Resolution X-ray Spectroscopy of Pre-Main-Sequence Stars: TWA 5 and PZ Tel

2004

We report on the analysis of high resolution X-ray spectra of two pre-main-sequence stars: TWA 5 (observed with XMM-Newton) and PZ Telescopii (observed with Chandra/HETGS). TWA 5 is a classical T Tauri star in the TW Hydrae association while PZ Tel is a rapidly rotating weak-lined T Tauri star in the beta-Pictoris moving group. For both stars we have reconstructed the emission measure distribution and derived the coronal abundances to check for possible patterns of the abundances related to the first ionization potential of the various elements. We have also derived estimates of the plasma density from the analysis of the He-like triplets. We compare the characteristics of our targets with …

Morfologia ed analisi delle immagini applicate allo studio dei bitumi modificati con polimeri

2009

Vengono presentati i risultati di uno studio di laboratorio condotto su campioni di bitume modificato con diversi tipi di polimeri e precisamente Stirene-butadienestirene (SBS), Etilen-vinilacetato (EVA) ed etilen-butilacrilato (EBA), le cui proprietà fisico-chimiche vengono riportate nell’articolo.

COMPARISON BETWEEN VEHICLE SPEED PROFILES ACQUIRED BY DIFFERENTIAL GPS AND UAV

2014

Traffic microscopic simulation models are able to represent traffic conditions and their evolution over time. They take into account the geometrical aspects of transport infrastructures, driver behavior and, step by step, the vehicles’ movements on the road network. The most widespread applications of these models are referred to accident management, route guidance problems (possibility of evaluating control strategies in real time), adaptive control of traffic-light and ramp metering (management and control of the ramps and flow). To accomplish this goal observational data of vehicles’ kinematic characteristics have to be acquired. These elements are not always easily available. In scienti…

Architetti e artisti nella chiesa di San Gioacchino

2008

Metodologia T.R.U.E. (Termografia, Radar, Ultrasuoni, Endoscopia).

2005

Metodologia d’indagine diagnostica finalizzata alla conservazione delle superfici intonacate e del supporto murario attraverso l’analisi comparata degli esiti della termografia, delle prospezioni radar ed ultrasoniche con il software T.R.U.E..

LA SOSTENIBILITÀ DELL’USO DEL SUOLO, LA VAS E LA GESTIONE DEL TERRITORIO, CON ALCUNI RIFERIMENTI ALLA REGIONE VENETO ED ALLA SICILIA

2009

Sommario Il problema nazionale, ma soprattutto meridionale ed in particolare della Regione Sicilia, della necessità di un approccio olistico, etico, civico ed interdisciplinare alla formazione di piani e programmi d’interesse pubblico, porta alla necessità di una formazione complessa scientifica ed umanistica. In particolare è strategico intersecare l’atteggiamento formativo ed applicativo delle progettualità ingegneristico-architettoniche con quello dei sistemi di conoscenza, valutazione sociale, economica ed ambientale, delle strutture organizzative e della programmazione economica. Occorrono competenze interdisciplinari con riferimento alle problematiche degli indicatori territoriali, am…

Segmentation and feature extraction in capillaroscopic videos

2015

This contribution describes a method to select regions of interest as capillaries of the oral mucosa and to extract their main features useful for real diagnosis purposes. A discrete version of the wavelet transform has been adopted for segmenting the images coming from video sequences acquired by a prototype capillaroscopic, able to put in evidence the red blood flow. A set of proper characteristics is automatically computed for a correct evaluation of the peripheral microcirculation.

ANALISI DELLO STATO TENSIONALE IN RESINE EPOSSIDICHE SOTTOPOSTE AD INVECCHIAMENTO IDROTERMICO MEDIANTE TECNICA FOTOELASTICA

2014

In questo lavoro si è analizzato lo stato tensionale che nasce in sistemi epossidici DGEBA quando sono sottoposti ad invecchiamento idro-termico, tramite la tecnica fotoelastica a trasmissione, basata sul metodo a variazione di fase di Compensazione di Tardy. I provini, monitorati ad intervalli di tempo regolari durante i processi di assorbimento e desorbimento di acqua, sono stati osservati al polariscopio circolare. La tecnica ha permesso di analizzare, sia qualitativamente, sia quantitativamente, lo stato tensionale indotto dal non uniforme “swelling” durante l’intero processo di invecchiamento. Inoltre, lo studio ha analizzato anche provini criccati di tipo Single Edge Notched Bending; …