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274 results on '"Sani, Elisa"'

52. Flooded mask for underwater and above-water vision

Author

Mercatelli, Luca, Sani, Elisa, Sansoni, Paola, Francini, Franco, Fontani, Daniela, and Jafrancesco, David

Subjects
Telescope -- Design and construction, Telescope -- Technology application, Aqualung -- Technology application, Engineering design -- Methods, Technology application, Astronomy, Physics
Abstract

An innovative flooded mask allows seeing both in air and underwater, thus overcoming the drawbacks of commercially available masks. The underwater telescope scheme is applied to a new flooded scuba mask obtaining correct eyesight in both underwater and above-water conditions. Optical design analyses and a test campaign on a sample of free divers have demonstrated that the mask is able to provide a well-corrected vision in both conditions. Three prototypes, with increasing optical performances, have been optically and mechanically optimized and then realized. OCIS codes: 080.2740, 220.3620, 330.4460, 330.1070.

Published
2010

53. Microstructural and optical properties of MgAl2O4 Spinel: Effect of Mechanical Activation, Yttrium and Graphene addition

Author

Obradović, Nina, Fahrenholtz, William G., Corlett, Cole, Filipović, Suzana, Nikolić, Marko G., Marinković, Bojan A., Failla, Simone, Sciti, Diletta, and Sani, Elisa

Subjects
magnesium aluminate, yttrium oxide, MgAl2O4, mechanical activation, solid-state reaction, oxide powders, technology, industry, and agriculture, ball milling, equipment and supplies
Abstract

Magnesium aluminate and other alumina-based spinels attract attention due to their high hardness, high mechanical strength, and low dielectric constant. MgAl2O4 was produced by solid-state reaction between MgO and α-Al2O3 powders. Mechanical activation of 30 minutes in a planetary ball mill was used to increase the reactivity of powders. Yttrium oxide and graphene were added to prevent abnormal grain growth during sintering. Samples were sintered by hot-pressing under vacuum at 1450 °C. Phase composition and microstructure of sintered specimens were characterized by X-ray diffraction analysis and scanning electron microscopy. Rietveld analysis revealed 100 % pure spinel phase in all sintered specimens, and decrease in crystallite size with the addition of yttria or graphene. Density measurements indicated that the mechanically activated specimen reached 99.6 % relative density, while other specimens were above 96.5 % relative density. Furthermore, the highest solar absorbance and highest spectral selectivity as a function of temperature were detected for the mechanically activated specimen with graphene addition. Mechanical activation is an efficient method to improve the densification behaviour of MgAl2O4 produced from mixed oxide powders, while additives improve microstructure and optical properties.

Published
2021

60. Spectroscopic analysis and diode-pumped laser results of Nd:BaY[subscript 2]F[subscript 8]

Author

Sani, Elisa, Toncelli, Alessandra, Tonelli, Mauro, Agnesi, Antonio, Guandalini, Annalisa, and Reali, Giancarlo

Subjects
Crystals -- Growth, Solid-state lasers -- Research, Spectrum analysis -- Research, Neodymium -- Research, Business, Computers, Electronics, Electronics and electrical industries
Abstract

Results of a room-temperature polarized infrared (IR) spectroscopic investigation of two Nd:BaYF crystals are reported.

Published
2003

65. Working Group Reports

Author

Hernandez, Leonor, Manca, Oronzio, Lugo, Luis, Murshed, Sohel, Sunden, Bengt, Ding, Yulong, Nieto de Castro, Carlos Alberto, Buschmann, Matthias, Sani, Elisa, COST Action Nanouptake, COST (European Cooperation in Science and Technology), and H2020

Subjects
nanofluids
Abstract

Final report of the five Working Group (WG) meetings have been held in the frame of Nanouptake during the whole duration of the Action

Published
2020

70. Absorption and scattering properties of carbon nanohorn-based nanofluids for direct sunlight absorbers

Author

Zaccanti Giovanni, Martelli Fabrizio, Di Ninni Paola, Barison Simona, Pagura Cesare, Agresti Filippo, Mercatelli Luca, Sani Elisa, and Jafrancesco David

Subjects
Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

Abstract In the present work, we investigated the scattering and spectrally resolved absorption properties of nanofluids consisting in aqueous and glycol suspensions of single-wall carbon nanohorns. The characteristics of these nanofluids were evaluated in view of their use as sunlight absorber fluids in a solar device. The observed nanoparticle-induced differences in optical properties appeared promising, leading to a considerably higher sunlight absorption with respect to the pure base fluids. Scattered light was found to be not more than about 5% with respect to the total attenuation of light. Both these effects, together with the possible chemical functionalization of carbon nanohorns, make this new kind of nanofluids very interesting for increasing the overall efficiency of the sunlight exploiting device. PACS 78.40.Ri, 78.35.+c, 78.67.Bf, 88.40.fh, 88.40.fr, 81.05.U.

Published
2011

71. Donor Centers Involved into the Quantum Cutting in Ytterbium‐Doped Scheelite‐Like Crystals.

Author

Subbotin, Kirill A., Titov, Anatolii I., Lis, Denis A., Sani, Elisa, Smirnov, Valerii A., Alimov, Olimkhon K., Zharikov, Evgenii V., and Shcherbakov, Ivan A.

Subjects
MOLYBDATES, TUNGSTATES, SINGLE crystals, CRYSTALS, PHOTOVOLTAIC cells, CHARGE transfer, PARAMETRIC downconversion
Abstract

Yb‐doped Scheelite‐like molybdate and tungstate single crystals are promising quantum‐cutting materials. The cooperative downconversion from donor centers to Yb ions occurs in heavily Yb‐doped crystals of this family. This phenomenon can substantially raise the efficiency of crystalline silicon photovoltaic cells. However, the nature of donor centers is still unknown. Herein, several versions of this nature are tested and discussed: Yb3+ ion (its high‐energy charge transfer states); Yb2+ ion; self‐trapped exciton at molybdate/tungstate complex; color centers based on oxygen vacancies; accidental impurities. To test these assumptions, a series of Scheelite‐like molybdate and tungstate single crystals (CaMoO4, CaWO4, NaLa(MoO4)2, NaGd(MoO4)2, NaGd(WO4)2, and NaY1−xGdx(WO4)2) are grown, both undoped and doped with different Yb‐concentrations. The complex spectroscopic investigations of these crystals are performed. As a result of the studies, three versions, self‐trapped excitons at [MoO4]/[WO4] complexes, color centers at oxygen vacancies, and accidental impurities, coming into the crystals with MoO3, are rejected. The applicability of the other versions should be refined. [ABSTRACT FROM AUTHOR]

Published
2020
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75. Ultra-refractory ceramics for high-temperature solar absorbers

Author

Sani Elisa [ 1 ], 1, Mercatelli Luca [ 1 ], Francini Franco [ 1 ], Sans J.-L. [ 2 ], and Sciti D. [ 3 ]

Subjects
Materials science, Thermodynamics, 02 engineering and technology, engineering.material, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Carbide, Zirconium carbide, chemistry.chemical_compound, Low emissivity, Emissivity, General Materials Science, Ceramic, Composite material, Refractory (planetary science), Mechanical Engineering, Metals and Alloys, Molar absorptivity, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Ultra-high-temperature ceramics, 0104 chemical sciences, chemistry, Mechanics of Materials, visual_art, visual_art.visual_art_medium, engineering, 0210 nano-technology, Optical emissivity, Carbides, Solar absorbers, Thermodynamic solar plants, Ultra-high temperature ceramics
Abstract

It is well known that the efficiency of thermodynamic solar plants increases with working temperature. At present the main limit to temperature upscaling is the capability of the absorber to withstand high temperatures. The ideal solar absorber works at high temperatures, has a low thermal emissivity and a high absorptivity in the solar spectral range. This paper reports on the high-temperature emissivity characterization of ceramic zirconium carbide samples. The investigation has been performed for samples of different chemical compositions.

Published
2011
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80. Ultra-High Temperature Ceramics for solar receivers: spectral and high-temperature emissivity characterization

Author

Sani Elisa [1], Mercatelli Luca [1], Fontani Daniela [1], Francini Franco [1], Jafrancesco David [1], Sansoni Paola [1], and Sans Jean-Louis [2]: Sciti Diletta [3]

Abstract

We report on the preparation, room temperature spectral reflectance and high-temperature thermal emissivity characterization of different Ultra-High Temperature Ceramics. We show that spectral and thermal emissivity properties of UHTCs are promising for solar receiver applications.

Published
2012

93. Image Optimization for a Linear CPV System

Author

Giannuzzi, Alessandra, primary, Sansoni, Paola, additional, Fontani, Daniela, additional, Francini, Franco, additional, Jafrancesco, David, additional, Mercatelli, Luca, additional, and Sani, Elisa, additional

Published
2010
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96. Room-temperature diode-pumped Yb:KYF_4 laser

Author

Galzerano, Gianluca, primary, Laporta, Paolo, additional, Sani, Elisa, additional, Bonelli, Lucia, additional, Toncelli, Alessandra, additional, Tonelli, Mauro, additional, Pesatori, Alessandro, additional, and Svelto, Cesare, additional

Published
2006
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