Direct sunlight facility for testing and research in HCPV

A facility for testing different components for HCPV application has been developed in the framework of "Fotovoltaico ad Alta Efficienza" (FAE) project funded by the Sicilian Regional Authority (PO FESR Sicilia 2007/2013 4.1.1.1). The testing facility is equipped with an heliostat providing a wide solar beam inside the lab, an optical bench for mounting and aligning the HCPV components, electronic equipments to characterize the I-V curves of multijunction cells operated up to 2000 suns, a system to circulate a fluid in the heat sink at controlled temperature and flow-rate, a data logging system with sensors to measure temperatures in several locations and fluid pressures at the inlet and ou…

Photoluminescence activity in natural silica excited in the vacuum-UV range

Abstract We report an experimental study on the optical absorption and photoluminescence detected in samples of natural silica. Our results show that the two emission bands, β (∼3.1 eV) and α E (∼4.3 eV), have an excitation profile in the vacuum ultraviolet region with a maximum at ∼7.5 eV. This excitation profile indicates that, in terms of energy levels of the luminescent defect, there is a transition from a ground state, S 0 , to a second excited state, S 2 , able to excite PL emission, in addition to the well known transition corresponding to the optical absorption band, B 2β . Our data are in a quantitative agreement with `ab initio' calculations carried out for a two-fold coordinated …

Fabrication of Bismuth Absorber Arrays for NTD-Ge Hard X-ray Microcalorimeters

The high-spectral-resolution detection of hard X-rays (E > 20 keV) is a challenging and nearly unexplored area in space astrophysics. Traditionally hard X-ray detectors present moderate spectral resolutions, although few tens of eV one could open new frontiers in the study of nuclear processes and high-temperature plasma dynamics in energetic processes. This can be achieved by using cryogenic microcalorimeters. Within a research activity aimed at developing arrays of neutron transmutation-doped germanium (NTD-Ge) microcalorimeters for the high-spectral-resolution detection (about 50 eV@60 keV) of hard X-rays (20 keV < E<100 keV), we developed an electroplating process to fabricate …

Experimental and Numerical Analysis of a Cross-Flow Turbine

An important component of the management cost of aqueducts is the energy costs. Part of these costs can be recovered by transforming some of the many existing energy dissipations into electric energy by means of economical turbines. This paper describes an experimental study that has been carried out in order to (1) test the performance of an economical cross-flow turbine that maintains high efficiency within a large range of water discharges, and (2) validate a new approximate formula relating main inlet velocity to inlet pressure. It is demonstrated that the proposed formula, on the basis of some simplifying assumptions, exactly links inlet velocity to inlet pressure with any possible geo…

ESPERIENZE FLUIDODINAMICHE SU UNA TURBINA DI PICCOLA POTENZA TIPO BANKI-MICHELL

The Large Observatory for X-ray Timing (LOFT)

High-time-resolution X-ray observations of compact objects provide direct access to strong-field gravity, to the equation of state of ultra-dense matter and to black hole masses and spins. A 10 m^2-class instrument in combination with good spectral resolution is required to exploit the relevant diagnostics and answer two of the fundamental questions of the European Space Agency (ESA) Cosmic Vision Theme "Matter under extreme conditions", namely: does matter orbiting close to the event horizon follow the predictions of general relativity? What is the equation of state of matter in neutron stars? The Large Observatory For X-ray Timing (LOFT), selected by ESA as one of the four Cosmic Vision M…

Experimental Study of Cross-flow Micro-turbines for Aqueduct Energy Recovery

An important component of the management cost of aqueducts is given by the energy costs. Part of these costs can be recovered by transforming some of the many existing energy dissipations in electric energy by means of economic turbines. In this study an experimental work has been carried out: 1) to test the performance of an economic Cross-Flow turbine which maintains high efficiency within a large range of water discharges, and 2) to validate a new approximated formula relating main inlet velocity to inlet pressure. It is proved that the proposed formula, according to some simplifying assumption, exactly links inlet velocity to inlet pressure according to any possible geometry of the Cros…

VALUTAZIONE DI DUE TEST IMMUNOCROMATOGRAFICI PER LA DIAGNOSI DI INFEZIONE DA ROTAVIRUS

Obiettivo dello studio: Valutare l’efficienza diagnostica di due tecniche immunocromatografiche (IC) utilizzate per la ricerca di antigeni di Rotavirus di gruppo A (RVA) nei campioni fecali: CerTest Rotavirus+Adenovirus (Biotec) e Vikia Rota+Adeno (bioMérieux). relazione Entrambe le tecniche IC sono state confrontate con la PCR RealTime, considerata il gold standard per la diagnosi delle enteriti da RVA. I RVA sono i principali agenti eziologici di gastroenterite acuta (AGE) nei bambini al di sotto dei 5 anni di età, con elevati tassi di morbilità e mortalità nelle diverse aree geografiche. Metodi impiegati: Uno studio retrospettivo è stato eseguito su 2096 campioni fecali, raccolti dal 200…

The NHXM observatory

Exploration of the X-ray sky has established X-ray astronomy as a fundamental astrophysical discipline. While our knowledge of the sky below 10 keV has increased dramatically (∼8 orders of magnitude) by use of grazing incidence optics, we still await a similar improvement above 10 keV, where to date only collimated instruments have been used. Also ripe for exploration is the field of X-ray polarimetry, an unused fundamental tool to understand the physics and morphology of X-ray sources. Here we present a novel mission, the New Hard X-ray Mission (NHXM) that brings together for the first time simultaneous high-sensitivity, hard-X-ray imaging, broadband spectroscopy and polarimetry. NHXM will…

Pattern and rate of post-20 ka verticaltectonic motion around Capo Vaticanopromontory (W Calabria, Italy) based onoffshore geomorphological indicators

The magnitude and rate of Late Pleistocene – Holocene vertical tectonic movements offshore Capo Vaticano (western Calabria) have been quantified on the basis of the depths of infralittoral prograding wedges (IPWs) and associated abrasion platforms formed during the stillstand of the Last Glacial Maximum (LGM). These features were identified on high-resolution reflection seismic profiles acquired along the continental shelf and upper slope around the promontory. The pattern of vertical movements of the Capo Vaticano promontory is characterized by a marked asymmetry associated with a NE-directed tilt. Removal of the non tectonic component of vertical changes using an ice-volume equivalent eus…

Performance analysis of two immunochromatographic assays for the diagnosis of rotavirus infection

Group A rotaviruses (RVAs) are the primary cause of acute gastroenteritis (AGE) in young children worldwide. Several commercial tests including latex agglutination, enzyme-linked assays (ELISA) and immunochromatographic tests (ICT) have been developed for the diagnosis of RVA infection. In the present study, the performance of two commercially available one-step chromatographic immunoassays, CerTest Rotavirus + Adenovirus (Biotec S.L, Zaragoza, Spain) and Vikia Rota-Adeno (bioMerieux SA, Lyon, France) were retrospectively evaluated using Real-time PCR as reference test. Re-testing by Real-time PCR of 2096 stool samples of children hospitalized with AGE previously screened by ICTs (1467 by C…

Cross-flow Turbine Design for Variable Operating Conditions

Abstract The potential energy hidden in water resources is becoming more and more a significant economic value. The value of the hydroelectric energy is often magnified by the proximity of the turbine to pumps or other energy sinks owned by the same water manager. Cross-flow or Banki-Michel turbines are a very efficient and economic choice that allows a very good cost/benefit ratio for energy production located at the end of conduits carrying water from a water source to a tank. In the paper the optimum design of a cross-flow turbine is sought after, assuming a flow rate variable in time. Regulation of the discharge entering in the turbine is a key issue, which is faced adopting a shaped se…

Planar Technology for NDT-Ge X-Ray Microcalorimeters: Absorber Fabrication

We have investigated the electroplating process to deposit thick uniform films of tin on a Ge wafer coated with Spin‐On Glass, in order to fabricate the absorbers for Ge microcalorimeter arrays. Here we discuss some technological details and propose two alternative metal bilayer to be used as seed for the electroplating.

Simple gas scintillation proportional counter soft x-ray detector for laboratory usage

Measuring magnitude and rate of vertical movements in the offshore Capo Vaticano (W Calabria) using lowstand coastal prisms and wave-built terraces

The magnitude and rate of vertical movements have been measured in the offshore Capo Vaticano (western Calabria) for the Late Pleistocene - Holocene on the basis of the depth of submerged coastal prism and associated wave-built terrace formed during the sea-level lowstand of the Last Glacial Maximum (LGM). Uplifted and submerged terraces have proved to be valuable recorders of vertical motion in many locations around the world (e.g. DICKINSON, 2001; WEBSTER et alii, 2004) as the depth of their tops appear to be controlled by the sea-level. In the eastern Tyrrhenian margins, depending on the hydraulic energy conditions (i.e. waves and wind-induced currents), the average water depth of terrac…

Guillem Peire de Cazals, “Be·m plagr’ueymais qu’ab vos dona·m valgues” (BdT 227.6)

This paper proposes a new edition with commentary of the poem “Be·m plagr’ueymais qu’ab vos, dona, ·m valgues” by Guillem Peire de Cazals and represents a first critical and hermeneutical reassessment of the poetry of the troubadour from Cahors, that has long been neglected. The text presents the classical structure of a love-story (springtime exordium, singing brought on by love, the theme of improvement, courting with no hope of a reward, a request for mercé) and invites the fin aman to be patient. The song is examined from the viewpoint of its metrical and stylistic relations to other troubadour poems (Bernart de Ventadorn, “Can par la flors josta·l vert folh” [BdT 70.41] and “La dousa v…

'Sens e razos d'una escriptura'. Per una nuova edizione critica della traduzione occitana dell'Evangelium Nicodemi

L'intervento intende presentare i risultati filologici e critici della riflessione condotta in margine all'allestimento di una nuova edizione critica della traduzione provenzale in versi dell'Evangelium Nicodemi. Il cosiddetto Vangelo apocrifo di Nicodemo, già stratificato fin dalle sue origini, è il frutto dell'unione di una storia sul Processo e sulla Passione di Cristo e della sua meravigliosa Discesa agli inferi, che riscuoterà un grandissimo successo nel Medioevo romanzo (e non). La traduzione in antico-occitano rimodella la sua fonte principale associandola con altri modelli latini di sapore apocalittico, tanto che l'ultima porzione del testo relaziona un racconto sull’Anticristo e su…

Sorveglianza molecolare delle gastroenteriti da rotavirus in Sicilia

Ampiezza e tassi dei movimenti verticali a Capo Vaticano (Calabria occidentale,Italia) negli ultimi 20 mila anni determinati sulla base di cunei progradanti epiattaforme di abrasione.

Ampiezza e tassi dei movimenti tettonici verticali sono stati quantificati nel settore offshore di Capo Vaticano (Calabria occidentale), nell’intervallo Pleistocene superiore – Olocene, sulla base delle profondità del ciglio dei cunei progradanti infralitorali e delle piattaforme di abrasione formatesi durante l’ultimo massimo glaciale (LGM). I cunei progradanti sono stati riconosciuti in profili sismici a riflessione ad alta risoluzione Sparker. I dati sismici sono stati acquisiti lungo la piattaforma e la scarpata continentale superiore, durante le crociere oceanografiche Marisk 2010 e 2012 organizzate dall’IAMC del CNR di Napoli, il DISTEM dell’Università di Palermo e il Dip. di Scienze …

Introduction and prolonged circulation of G12 rotaviruses in Sicily

SUMMARYGenotype G12 strains are now considered to be the sixth most prevalent human rotaviruses worldwide. In two Sicilian cities, Palermo and Messina, surveillance of rotavirus circulation performed since 1985 and 2009, respectively, did not detect G12 strains until 2012. From 2012 to 2014 rotavirus infection was detected in 29·7% of 1647 stool samples collected from children admitted for acute gastroenteritis to three Sicilian hospitals in Palermo, Messina and Ragusa. In 2012, G12P[8] was first detected in Palermo and then in Messina where it represented the second most frequent genotype (20% prevalence) after G1P[8]. Thereafter, G12 strains continued to circulate in Sicily, showing a mar…

Absorption band at 7.6 eV induced by γ-irradiation in silica glasses

Optical absorption of defects induced by γ-irradiation in both natural and synthetic silica is experimentally investigated in the vacuum-ultraviolet (UV) range. Our results show that γ-rays, in a dose range of 1000 Mrad, induce an absorption band centered at 7.6 eV, the so-called E band, whose growth kinetics is not related to γ-activated precursors but to defects of the glassy matrix directly induced via the breaking of Si–O bonds occurring under γ-irradiation. Moreover, we observe that γ-rays do not bleach the E band present in some silica samples before irradiation, so ruling out that the associated defects can be precursors of the paramagnetic E′ centers, also induced by γ-irradiation.

Simbol-X Mirror Module Thermal Shields: II-Small Angle X-Ray Scattering Measurements

The formation flight configuration of the Simbol-X mission implies that the X-ray mirror module will be open to Space on both ends. In order to reduce the power required to maintain the thermal stability and, therefore, the high angular resolution of the shell optics, a thin foil thermal shield will cover the mirror module. Different options are presently being studied for the foil material of these shields. We report results of an experimental investigation conducted to verify that the scattering of X-rays, by interaction with the thin foil material of the thermal shield, will not significantly affect the performances of the telescope.

Chemical Evolution of Interstellar Methanol Ice Analogs upon Ultraviolet Irradiation: The Role of the Substrate

An important issue in the chemistry of interstellar ices is the role of dust materials. In this work, we study the effect of an amorphous water-rich magnesium silicate deposited onto ZnSe windows on the chemical evolution of ultraviolet-irradiated methanol ices. For comparison, we also irradiate similar ices deposited onto bare ZnSe windows. Silicates are produced at relatively low temperatures exploiting a sol-gel technique. The chemical composition of the synthesized material reflects the forsterite stoichiometry. Si-OH groups and magnesium carbonates are incorporated during the process. The results show that the substrate material does affect the chemical evolution of the ice. In particu…

Simbol-X Mirror Module Thermal Shields: I-Design and X-Ray Transmission

The Simbol‐X mission is designed to fly in formation flight configuration. As a consequence, the telescope has both ends open to space, and thermal shielding at telescope entrance and exit is required to maintain temperature uniformity throughout the mirrors. Both mesh and meshless solutions are presently under study for the shields. We discuss the design and the X‐ray transmission.

Metal thin-film temperature sensor embedded in heat-sink for CPV cells characterization

The efficiency of a photovoltaic cell is dependent on its temperature, for this reason an accurate measurement of this parameter is important to fully characterize the device and to optimize its performance. For CPV applications a significant heat flux is needed to remove excess heat from the cell towards a heat sink, making it difficult to derive the cell temperature. In fact, measurements performed directly between the cell and the heat-sink, by use of commercial bulk sensors, would produce a significant disturbance in the heat flow; on the other hand, a measurement performed out of the cell / heat sink axis would be subject to large uncertainties, due to the high radial temperature gradi…

The European Photon Imaging Camera on XMM-Newton: The MOS Cameras

The EPIC focal plane imaging spectrometers on XMM-Newton use CCDs to record the images and spectra of celestial X-ray sources focused by the three X-ray mirrors. There is one camera at the focus of each mirror; two of the cameras contain seven MOS CCDs, while the third uses twelve PN CCDs, defining a circular field of view of 30 arcmin diameter in each case. The CCDs were specially developed for EPIC, and combine high quality imaging with spectral resolution close to the Fano limit. A filter wheel carrying three kinds of X-ray transparent light blocking filter, a fully closed, and a fully open position, is fitted to each EPIC instrument. The CCDs are cooled passively and are under full clos…

Progettazione di un'opera di presa a basso impatto ambientale per un impianto mini idroelettrico in Sicilia

Innovative techniques to reduce chilling injuries in mango (Mangifera Indica L.) trees under mediterranean climate

As a tropical tree, mango (Mangifera indica L.) cultivated in Mediterranean climate needs protection against low temperatures. The aim of this work is to study the effect of traditional individual protective canopy protection systems in comparison with innovative typologies designed for this experiment on the physiological response of young mango trees during the cold season. We selected 25 four-year-old mango trees cv ‘Glenn’. Trees were divided into five different groups: not covered trees (NC); trees with windbreak protection using a shading net (SN); trees with windbreak protection using non-woven sheets (WB); fully covered trees using non-woven sheets (FC); fully covered trees with non…

Optical/UV filters for the EPIC experiment

The European Photon Imaging Cameras (EPIC) is an experiment based on cooled CCD's 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 fuer Extraterrestrische Physik (MPE, Germany) have been described elsewhere. The two filters, here described, have a 1600 angst…