Search results for " ceramic"

Fracture Resistance of New Metal-Free Materials Used for CAD-CAM Fabrication of Partial Posterior Restorations

2020

Background and Objectives: To evaluate in vitro the fracture resistance and fracture type of computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: Discs were fabricated (10 &times

Neolithic ceramic findings from western Sicily. Chemical – physical and mineralogical characterization

2001

This paper presents the results of a study that is part of a wider research program regarding the knowledge of the initial living phases of Sicilian agricultural and pastoral societies.Three ceramic samples attributed to the medium initial Neolithic (NEO1 and NEO2) and to the first neolithic (NEO3), recovered in two different archaeological sites of the western Sicily, have been analysed. Chemical, mineralogical and spectroscopic data point out a similarity between NEO1 and NEO3 samples; compositional and morphological differences instead have been observed in the NEO2 sample. The firing temperatures of the samples have been estimated by Mössbauer spectroscopy; they are lower than 500°C for…

Investigation of hydrogen and deuterium impact on the release of tritium from two-phase lithium ceramics under reactor irradiation

2022

In the development of fusion energy, an important task is the study and improvement of tritium production technologies. In this case, one of the most promising materials for tritium generation is lithium ceramics. Considering the importance of the task, numerous studies are aimed at solving the problem of determining the parameters and mechanisms of tritium release in lithium-containing materials. This paper presents the results of a study of tritium release processes from two-phase lithium ceramics of Li$_{4}$SiO$_{4}$/Li$_{2}$TiO$_{3}$ during reactor irradiation when hydrogen and deuterium are injected into the chamber with irradiated samples. The mechanisms regularities of the tritium yi…

Time-resolved luminescence of YAG:Ce and YAGG:Ce ceramics prepared by electron beam assisted synthesis

2020

Abstract The luminescence characteristics of YAG:Ce and YAGG:Ce ceramic phosphors produced by electron beam assisted synthesis have been investigated. The obtained emission and decay kinetics characteristics have been compared with those for commercial phosphors synthesized by conventional methods and showed good qualitative and quantitative correspondence. In our opinion, the used electron-beam-assisted synthesis method could be considered as a perspective production method of high refractory multicomponent oxide ceramics.

Étude typologique, technologique et culturelle de la céramique du Petit-Paulmy à Abilly (Indre-et-Loire)

2009

Anhand einer qualitativen und quantitativen Studie wurden die minimale und die maximale Anzahl der dem Endneolithikum zugeordneten Keramikindividuen ermittelt. Der Corpus umfasst drei typologische und technische Gruppen, die drei chronologischen und kulturellen Phasen entsprechen. Eine Quantifizierung der unterschiedlichen Formen vermittelt ein Bild des endneolithischen Keramikrepertoires des Fundplatzes. Der für die Herstellung der Keramik benutzte Ton ist lokaler Herkunft. Es existiert eine Korrelation zwischen der Dicke der Wandung, der Form der Gefäße und den unterschiedlichen Herstellungstechniken (Glättung, Schaben, Schlagen, Kieselglättung). Die Gefäße der drei Hauptformen wurden in …

Convergence angles of all-ceramic full crown preparations performed in Dubai private practice

2018

Background This study aimed to determine the degree of taper and total occlusal convergence angles (TOC) for all-ceramic bonded crown preparations carried out by private practitioners in Dubai, UAE. Material and Methods A convenience sample of all-ceramic crown preparations carried out by private dental practitioners were scanned (Carestream CS 3500) from casts and the digital images assessed. The degree of taper was measured on the axial walls of each crown preparation and the bucco-lingual and mesio-distal convergence angles subsequently calculated. Results A total of 154 dentists prepared a total of 206 crown preparations (72 anterior, 134 posterior). The mean convergence angles mesio-di…

Dielectric properties of barium strontium titanate / non ferroelectric oxide ceramic composites

2001

International audience; Barium strontium titanate ceramics present high dielectric permittivity and tunability. In order to reduce their permettivity and loss tangent while keeping tunability, various composites of barium strontium titanate oxide...

EPR Study of Manganese-Doped PLZT-8/65/35 Ceramics

1992

Synthesis and reactivity of cristobalite obtained from the SiO2-V2O5 system

1990

On etudie par diffraction RX l'evolution des phases cristallines lors de la cuisson a 650-1250 o C de compositions du systeme ZrO 2 −V 2 O 5 −SiO 2 et la reactivite de la cristobalite preparee avec la phase ZrO 2 monoclinique

X-ray powder diffraction phase analysis and thermomechanical properties of silica and alumina porcelains

2004

Chemical and mineralogical characterization, using the Rietveld method, of some silica and alumina rich porcelains and its relationship with thermomechanical properties have been studied in this work. X-ray powder diffraction analysis allows to differ clearly between silica and alumina porcelains. X-ray study shows that both porcelains have a content of vitreous phase. This vitreous phase is higher in the silica than in the alumina porcelain. Dilatometric studies combined with powder diffraction methods shows a strong relationship between silica content and a lower expansion coefficients and between alumina content and a higher crash resistance. Lower contents in vitreous phase in porcelain…