Search results for " ceramic"
showing 10 items of 228 documents
Le anfore fenicio-puniche prodotte nel Mediterraneo occidentale: caratteristiche petrografiche degli impasti siciliani e spagnoli.
2009
The aim of this paper is to provide well-stated petrographic reference groups for the recognition of several Sicilian and Spanish Phoenician-Punic production centres in order to facilitate an instrument of further objective support for amphorae provenance. This instrument is based on the crosschecking between data provided by typological studies and the thinsection analysis of amphorae fabrics. It is worth noting that this is only a first step within the framework of a larger research project focused in the creation of an Atlas of Phoenician and Punic Amphorae in the Western Mediterranean including both archaeological and petrographic data. In this context a systematical work on the known p…
STUDIO DI UN’APPLICAZIONE IN CAMPO AERONAUTICO DI COMPOSITI STRUTTALI IBRIDI RESISTENTI AL FUOCO
2013
In the aeronautical/aerospace structural design the increasing demands of materials having high mechanical performance, has led to the a wide use of Polymeric Matrix Composites (PMCs) mainly reinforced by carbon fibers (Carbon Fiber Reinforced Plastics, CFRP). The main drawbacks in the use of such composites are due to high sensitivity to environmental features and low working temperatures; moreover, these materials do not tolerate the fire exposure because of the inflammability of both the matrix and the fibers. In order to develop a composite that combines the structural performance of CFRP with a good strength to high temperatures and fire, in the present work the use of a hybrid composi…
Eu3+ ion distribution in oxyfluoride glass nanocomposites
2019
The authors are grateful to Dr. Andris Fedotovs for photography of the samples. This research is funded by the Latvian Council of Science, project “Novel transparent nanocomposite oxyfluoride materials for optical applications”, project No. LZP-2018/1-0335.
Progress in the benchmark exercise for analyzing the lithiate breeder pebble bed thermo-mechanical behaviour
2006
The Helium Cooled Pebble Bed (HCPB) Blanket is one of the reference concepts for the European Breeding Blanket Programme for DEMO. In the reference blanket module, alternate layers of lithiated ceramics and beryllium pebbles act, respectively, as tritium breeder and neutron multiplier. The thermo-mechanical behaviour of both the pebble beds and their performances in reactor relevant conditions are also dependent on the pebble size and cell geometries (bed thickness, pebble packing factor, bed thermal conductivity). Therefore, in the EU Fusion Technology Programme, several out-of-pile experimental test campaigns have been performed to determine these behaviours. Theoretical calculations have…
Severe tetracycline dental discoloration: Restoration with conventional feldspathic ceramic veneers. A clinical report
2017
The treatment of severe tetracycline discoloration is a challenge for the dentist. There are several treatment options and one of the most effective is the use of feldspathic veneers. The aim of this clinical case was to carry out the replacement with conventional feldspathic ceramic veneers on a patient with highly stained teeth (grade IV tetracycline) by a minimally invasive approach. Clinical examination revealed gingival retraction, color change of the veneers, ceramic cracked of 1.1 and 1.3 and incisal wear in lower anterior teeth. The decision was to retreat with feldspathic ceramic veneers from 1.6 to 2.6. Premolars and first molars were included because its dark color intensifies th…
Cubic and rhombohedral Ba4Lu3F17:Er3+ in transparent glass ceramics: Crystallization and upconversion luminescence
2018
CC BY-NC-ND
Upconversion luminescence of a transparent glass ceramics with hexagonal Na(Gd,Lu)F4 nanocrystals
2017
Novel Er3+ doped transparent glass ceramics containing hexagonal Na(Gd,Lu)F4 nanocrystals were prepared from oxyfluoride glasses. The distribution of rare earth ions in the crystalline and glassy phase has been analyzed by X-ray diffraction and erbium luminescence decay kinetics measurement. A strong deviation of rare earth ion content in fluoride nanocrystals in comparison to the base glass has been observed. Preferential incorporation of Gd3+ over Lu3+ ions in the fluoride lattice leads to the stabilization of hexagonal Na(Gd,Lu)F4 structure and prevents the formation of cubic fluorite type solid solutions. A considerable enhancement of upconversion luminescence correlates with the format…
Electron paramagnetic resonance and photoluminescence investigation of europium local structure in oxyfluoride glass ceramics containing SrF2 nanocry…
2017
Different compositions of europium doped aluminosilicate oxyfluoride glass ceramics prepared in air atmosphere have been studied by electron paramagnetic resonance (EPR) and optical spectroscopy methods. X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements show presence of homogenously distributed SrF2 nanocrystals after the heat treatment of the precursor glass. Efficient Eu3+ incorporation in the high symmetry environment of glass ceramics is observed from the photoluminescence spectra. EPR spectra indicate Eu3+ → Eu2+ reduction upon precipitation of crystalline phases in the glass matrix. For composition abundant with Eu2+ in the glassy state such behaviour is …
Dinamiche di popolamento e processi di trasmissione culturale nel comprensorio madonita attraverso la ricostruzione della viabilità antica
2020
La ricerca sulle Madonie nasce con l’intenzione di approfondire l’evoluzione storica del popolamento sulla regione montana della Sicilia nord-occidentale. Il territorio, che solo in anni recenti è divenuto oggetto di più approfondite ricerche storico-archeologiche, si presenta estremamente ricco di risorse naturali e caratterizzato da un sostrato culturale variegato che abbraccia territori d’alta montagna, dediti ad una economia silvo-pastorale prettamente conservativa, e insediamenti costieri fortemente proiettati allo scambio e al commercio. A fine di comprendere lo sviluppo delle dinamiche d’insediamento di un’area molto estesa, si è proceduto anzitutto con la restituzione ipotetica dei …
Augmentation of tibial plateau fractures with an injectable bone substitute: CERAMENT™. Three year follow-up from a prospective study
2015
Background: Reduction of tibial plateau fractures and maintain a level of well aligned congruent joint is key to a satisfactory clinical outcome and is important for the return to pre-trauma level of activity. Stable internal fixation support early mobility and weight bearing. The augmentation with bone graft substitute is often required to support the fixation to mantain reduction. For these reasons there has been development of novel bone graft substitutes for trauma applications and in particular synthetic materials based on calcium phosphates and/or apatite combined with calcium sulfates. Injectable bone substitutes can optimize the filling of irregular bone defects. The purpose of this…