LA SFIDA DI MISTRETTA PER UNA RINASCITA CULTURALE ATTRAVERSO LA VALORIZZAZIONE DEL SUO PATRIMONIO STORICO-ARTISTICO

una breve rassegna di suppellettili liturgiche restaurate appartenenti alla Chiesa Madre di Santa Lucia di Mistretta.

Development of the UV/ion shields for the Advanced X-ray Astrophysics Facility high-resolution camera (AXAF HRC)

The Advanced X-ray Astrophysics Facility (AXAF) is a major NASA space observatory (launch 1998). One of its two focal plane detectors is the High Resolution Camera (HRC) assembly consisting of two microchannel plate (MCP) based detectors. Key components of the two HRC detectors are UV/Ion shields consisting of metalized sub-micron plastic membranes, designed to prevent UV light and low energy charged particles from reaching the detectors' sensitive surfaces. We discuss the design issues and present results of recent measurements and tests. Soft X-ray/UV transmission measurements have been conducted at the Space Science Laboratory (SSL), University of California at Berkeley, and at the Osser…

Conventi e opere d’arte francescane dei Nebrodi: Patti, Sant’Angelo di Brolo e Alcara Li Fusi.

Una breve descrizione dell'attività dei Padri Francescani nell'area dei Nebrodi, ancora oggi visibile grazie alla presenza di conventi, chiese e opere in essi custodite. Un viaggio tra i tesori dell'Ordine di Patti, Sant'Angelo di Brolo e Alcara Li Fusi.

Coronal loop hydrodynamics. The solar flare observedon November 12 1980 revisited: the UV line emission

We revisit a well-studied solar flare whose X-ray emission originating from a simple loop structure was observed by most of the instruments on board SMM on November 12 1980. The X-ray emission of this flare, as observed with the XRP, was successfully modeled previously. Here we include a detailed modeling of the transition region and we compare the hydrodynamic results with the UVSP observations in two EUV lines, measured in areas smaller than the XRP rasters, covering only some portions of the flaring loop (the top and the foot-points). The single loop hydrodynamic model, which fits well the evolution of coronal lines (those observed with the XRP and the \FeXXI 1354.1 \AA line observed wit…

Structural design of Fiumara d'Arte land art works

Spectral broadening by incomplete thermalization of the energy in X-ray microcalorimeters with superconducting absorber and NTD-Ge thermal sensor

Abstract We present a model of the response of a cryogenic microcalorimeter with superconducting absorber and phonon sensitive thermal sensor to the absorption of X-ray photons. The model is based on the main microscopic processes responsible for the thermalization of the deposited energy. We use a system of rate equations to describe the energy downconversion in the superconductor and transport to the thermal sensor. The model is a tool to investigate the thermalization efficiency with respect to the device characteristics (i.e. absorber material, geometry), in order to optimize the performances of these detectors. As a first case study, we report results of simulations for a microcalorime…

The improvement of science teaching and the role of the institutions to improve the quality of pre-service and in service teaching education

Argenti messinesi ad Alcara Li Fusi

L’autore studia un importante novero di suppellettili liturgiche di manifattura messinese presenti ad Alcara Li Fusi, comune della provincia di Messina. Questi manufatti, molti dei quali inediti, fanno parte della collezione del museo di Arte Sacra del piccolo centro dei Nebrodi. L’articolo è un ulteriore contributo per tracciare un quadro storico-artistico il più esaustivo possibile sulla, non ancora ben conosciuta, maestranza della città dello Stretto.

One-dimensional hydrodynamic modeling of coronal plasmas on transputer arrays

Abstract We describe a concurrent implementation of the Palermo-Harvard hydrodynamic code on cost-effective and modularity expandable transputer arrays. We have tested the effectiveness of our approach by simulating an already well-studied compact solar-flare model on different transputer configurations and compared their performances with those of other machines. We have found that the speed of the concurrent program on a 16-T800 transputers array is ~1/9 of that of the equivalent code optimized for a CRAY X-MP/48. This work clearly shows that transputer-based arrays provide locally available high computing-power tools to extend the investigation of compact solar flares and similar astroph…

RECENSIONE DEL LIBRO "Sicilia Ritrovata. Arti decorative dai Musei Vaticani e dalla Santa Casa di Loreto"

Recensione del libro Di Natale M.C.,Cornini G. e Utro U. ( a cura di) (2012), Sicilia Ritrovata. Arti decorative dai Musei Vaticani e dalla Santa Casa di Loreto,Plumelia edizioni, Bagheria (Palermo)

Spectral broadening by spatial effects in X-ray microcalorimeters with superconducting absorber and NTD-Ge thermal sensor

We discuss how the sensitivity to the position of absorption of the photons can affect the spectral resolution of X-ray microcalorimeters with superconducting Sn absorber and NTD-Ge thermal sensor. Data obtained through the computer simulations are reported for microcalorimeters with different geometries and phonon transmission probabilities at the interface between the absorber and thermistor.

Argenti messinesi del XVII e XVIII secolo

La tesi trae spunto dalla mancanza di un esaustivo profilo storico e storico-artistico di una delle maestranze più importanti della Sicilia, quella degli argentieri messinesi del XVII e XVIII secolo. Attraverso l' analisi di numerose opere e dei relativi marchi, e al confronto con le modalità di punzonatura di altri centri (Sicilia, Napoli e la Spagna) si è cercato di aggiungere nuove e preziose informazioni per accostare un nome ai punzoni rilevati.

CALOS: an experiment to study the solar corona with an array of NTD Ge microcalorimeters

In response to the Italian Space Agency announcement "New Ideas for Space Missions", we have proposed an observatory "CALorimetri per Osservazioni Solari" (CALOS) that will perform spatially resolved (Deltatheta similar to 2) X-ray spectroscopy of the solar corona over the 0.1 - 10 keV band using an array of NTD germanium microcalorimeters. The observatory will also include an X-ray polarimeter of radically new design that will study the hard X-ray solar emission and its polarization and will serve as a flare alarm.

A Brightening Coronal Loop Observed byTRACE. II. Loop Modeling and Constraints on Heating

This is the second of two papers dedicated to the brightening of a coronal loop observed by the Transition Region and Coronal Explorer (TRACE) on 1998 June 26; it aims at hydrodynamic modeling of the brightening. Since the loop geometry is practically unchanged during the brightening, the evolution of the plasma confined in the loop is described with a one-dimensional hydrodynamic time-dependent numerical model, and from the results the emission along the loop in the TRACE 171 A band is synthesized. The information from Paper I is used to derive the geometry and the initial configuration of the loop as well as for comparison with the results of the model. The modeling is focused to determin…

A Brightening Coronal Loop Observed byTRACE. I. Morphology and Evolution

We analyze the transient brightening of a solar coronal loop observed, at high time cadence (30 s) and spatial resolution (05 pixel size), with the Transition Region and Coronal Explorer (TRACE) in the 171 A band on 1998 June 26. The loop, located in AR 8253, is ≈1010 cm long and inclined with respect to the vertical to the solar surface. Its geometry and shape do not change significantly during the brightening, which lasts for ~2 hr and is preceded by highly dynamic events in nearby and perhaps interacting loops. The loop footpoints brighten first; after ~10 minutes, moving brightness fronts rise initially from the northern footpoint, and after another ~7 minutes from the southern one, at …

A single stage adiabatic demagnetization refrigerator for testing x-ray microcalorimeters

A single stage Adiabatic Demagnetization Refrigerator (ADR), has been set-up at the X-ray Astronomy Calibration and Testing (XACT) facility of INAF - Osservatorio Astronomico di Palermo G.S. Vaiana, for the development and testing of cryogenic X-ray detectors for laboratory and astrophysical applications. The ADR allows to cool detectors at temperatures below 40 mK and to maintain them at constant operating temperature for many hours. We describe the design and construction of the ADR and present test results and performances.

Thermal conduction and modeling of static stellar coronal loops

We have modeled stellar coronal loops in static conditions for a wide range of loop length, plasma pressure at the base of the loop and stellar surface gravity, so as to describe physical conditions that can occur in coronae of stars ranging from low mass dwarfs to giants as well as on a significant fraction of the Main-Sequence stars.

The optical/UV filters for the EPIC experiment

EPIC, the European Photon Imaging Cameras is an experiment based on cooled CCDs on board the ESA X-ray Multi Mirrors satellite due to be launched in 1999. Since CCD's are sensitive to radiation other than X-rays, namely Optical and UV light, filters are necessary to prevent this radiation from reaching the detector sensitive area. Three types of filters were developed, to be used alternatively depending on target source. Here we report on the medium and thin filters developed by MOXTEK Inc. in Orem, Utah, while the thick ones, developed at the Max-Planck-Institut fur Extraterrestrische Physik (MPE, Germany) have been described elsewhere. The two filters, described here, have a 1600 /spl Ari…

EBIT diagnostics using X-ray spectra of highly ionized Ne

We have carried out a detailed analysis of highly ionized neon spectra collected at the NIST EBIT using an NTD germanium X-ray microcalorimeter developed at the Harvard-Smithsonian Center for Astrophysics [Nucl. Instr. and Meth. A 444 (2000) 156]. Our attention was focused especially on the Ne IX He-like triplet to check electron density diagnostics through the intercombination/forbidden line ratio. We have investigated possible effects of the ion dynamics on the plasma emission line intensities, looking at the dependence of the count-rate and the charge state distribution on the electron beam energy and current. The temperature and spatial distribution of the neon ions, and hence the overl…

Cent'anni fa

Cent'anni fa

Gli argenti liturgici dei Padri Liguorini di Agrigento

Il contributo offre un ampio quadro delle suppellettili in argento esposte nella mostra "Arredi e Collezioni dei Padri Liguorini di Agrigento. Tutela e conservazione", evidenziandone l'alta qualità artistica e la varietà tipologica e cronologica.

Cent'anni fa

Il Museo di Arte Sacra a S. Angelo di Brolo

Il volume, ripercorrendo il percorso espositivo e con dettagliate schede, sottopone le opere d’arte, custodite all’interno del Museo di Arte Sacra di Sant’Angelo di Brolo, ad uno studio scrupoloso in cui si cerca di esaminare lo stile e la tipologia, di stabilire confronti con altri manufatti analoghi dello stesso territorio o di altri luoghi per una più esatta collocazione cronologica, di indicare, quando le iscrizioni incise nelle stesse opere lo consentivano, anche la relativa committenza. Per le opere in argento, si è tentato di rilevare i marchi di garanzia, i punzoni dei consoli delle rispettive maestranze, nonché le iniziali degli artefici.

Non-local heat transport in static solar coronal loops

We investigate the limits of applicability of the Spitzer-Harm thermal conductivity in solar coronal loops and show that the ratio λ0/LTof electron mean-free path to temperature scale height in large-scale structures can approach the limits of the Spitzer-Harm theory. We use a non-local formulation of heat transport to compute a grid of loop models: the effects of non-local transport on the distribution of differential emission measure are particularly important in the coronal part of loops longer than the pressure scale height sp.We derive a scaling law for λ0/LTin the corona, showing that it grows exponentially with L/sp, and discuss effects of non-local heat transport in the transition r…

Cent'anni fa

Alcuni aspetti critici sulla fortuna della tecnica degli smalti.

L'articolo analizza tutte le tecniche della lavorazione degli smalti tra tradizione e innovazione.

A two-dimensional hydrodynamic code for astrophysical flows

We present a two-dimensional hydrodynamic code suited to study astrophysical flows in many different environments. The code solves the hydrodynamic equations in conservative form in the most used coordinate systems and is based on an explicitfully two-dimensional flux corrected transport (FCT) technique, which ensures an accurate description of steep gradient regions and shocks, a relatively ample flexibility to include a variety of physical effects, and a good efficiency for speed on vector or array processors. Extensive testing has allowed an accurate «tuning» of the FCT numerical parameters. This code is among the best FCT codes and performs well in a whole set of demanding strongly nonl…

Spectral broadening by quasiparticle pile-up in X-ray microcalorimeters with superconducting absorbers

Long-living quasiparticles can pile-up in a superconducting absorber of an X-ray microcalorimeter when photons are detected at high count rate. These quasiparticles can give a non-negligible contribution to the total heat capacity of the detector thus affecting the pulse height spectrum of detected photons. We investigated this effect with numerical simulations and evaluated the resulting spectral broadening as a function of the photon absorption rate, and the heat capacity of the detector for a NTD germanium microcalorimeter with pure Sn absorber.

Monitoring the stability of thin and medium back-up filters of the Newton-XMM EPIC camera

We are conducting a measurement program on back-up filters of the XMM-Newton EPIC camera aimed at monitoring possible aging effects during the mission lifetime. One thin and one medium EPIC back-up filters have been stored since 1997 in an environment similar to that one of the flight filters (dry nitrogen box before launch, high vacuum after launch). The transmission of the two filters has been measured periodically in the 1900-10000 angstrom wavelength range where effects of aging would be clearly evident. The preliminary results, after 5 years of monitoring, show that a slight aging effect has occurred on both filters which, however, has no significant impact onto the EPIC calibration fo…

Cent'anni fa

Thermalization efficiency of superconducting absorbers for thermal X-ray microcalorimeters

The persistence of long living quasiparticles created in the energy thermalization process can affect the performances of a thermal X-ray microcalorimeter with superconducting absorber. Numerical simulations indicate that in an ab- sorber made of high-purity Sn, operated at temperatures lower than 100 mK, up to 60% of the deposited energy can remain trapped in the quasiparticle system for a time much longer than the time scale of the thermal sensor response, producing a reduction of the SNR of the detector. Other pure superconductors can present the same problem and therefore a microscopic analysis of the physical properties can be useful to identify suitable absorbing materials and optimiz…

Cent'anni fa

Cent'anni fa

Modeling the energy thermalization of X-ray photons in a microcalorimeter with superconducting absorber

We present a modeling of the response of a microcalorimeter to the absorption of X-ray photons, based on the main microscopical processes responsible for the energy thermalization. In particular, we have modeled a microcalorimeter with superconducting tin absorber (350 micron x 350 micron x 7 micron) and neutron transmutation doped (NTD) germanium thermistor (75 micron x 50 micron x 150 micron). Such a detector, operated at 60 mK, is expected to achieve a spectral resolution as good as 1 eV FWHM in the soft X-ray energy range, based on the known sources of thermal and electronic noise. Nevertheless, the best spectral resolution measured in laboratory experimental tests is of about 5 eV FWHM…

Cent'anni fa. GIORNALE DI ASTRONOMIA. vol. 31, pp. 1.36-1.38 ISSN: 0390-1106

Scheda IV.17, argentiere palermitano del quinto decennio del XVIII secolo, console Antonino Pensallorto, ostensorio, argento dorato sbalzato, cesellato e parti fuse, Alcamo (TP), Museo d'Arte Sacra della Basilica Santa Maria Assunta

Scheda storico-artistica dell'ostensorio di maestranza palermitana del quinto decennio del XVIII secolo e vidimato dal console Antonino Pensallorto. L'opera è custodita nel Museo d'Arte Sacra della Basilica Santa Maria Assunta di Alcamo.