Search results for "Ceramic"
showing 10 items of 2129 documents
High performance composites containing perfluoropolyethers-functionalized carbon-based nanoparticles: Rheological behavior and wettability
2016
Abstract Ultra High Molecular Weight Polyethylene (UHMWPE) based composites filled with carbon nanotubes (CNTs) and carbon black (CB) modified by perfluoropolyethers (PFPE) have been formulated. All composites show a segregated morphology with nanofillers selectively localized at the polymer particle–particle interface. The composites rheological properties have been deeply investigated: the PFPE functionalities linked on CNTs facilitate the semi-3D nanofillers network formation in the composites that show a solid-like behaviour even at lower investigated filler contents, reaching the rheological percolation threshold at lower nanofiller content than bare CNTs filled composites. For composi…
Impedance investigation of BaCe0.85Y0.15O3-delta properties for hydrogen conductor in fuel cells
2012
International audience; The influence of the sintering conditions on the electrochemical properties of the proton conducting electrolyte BaCe0.85Y0.15O3-delta (BCY15) and Ni - based BCY15 cermet anode for application in high temperature proton conducting fuel cell are investigated by electrochemical impedance spectroscopy. The results show that at lower sintering temperatures due to the formation of parasitic Y2O3 phase an increase of both the electrolyte and electrode resistances is observed. This effect is strongly reduced by enhancement of the sintering temperature. The obtained BCY15 conductivity (sigma = 2.5x10(-2) S/cm at 700 degrees C) is comparable with that of the best proton condu…
Bioencapsulation of living bacteria (Escherichia coli) with poly(silicate) after transformation with silicatein-α gene
2007
Bioencapsulation is an intriguing way to immobilize biological materials, including cells, in silica, metal-oxides or hybrid sol-gel polymers. Until now only the sol-gel precursor technology was utilized to immobilize bacteria or yeast cells in silica. With the discovery of silicatein, an enzyme from demosponges that catalyzes the formation of poly(silicate), it became possible to synthesize poly(silicate) under physiological (ambient) conditions. Here we show that Escherichia coli can be transformed with the silicatein gene, its expression level in the presence of isopropyl beta-D-thiogalactopyranoside (IPTG) can be efficiently intensified by co-incubation with silicic acid. This effect co…
A review on basalt fibre and its composites
2015
Abstract In recent years, both industrial and academic world are focussing their attention toward the development of sustainable composites, reinforced with natural fibres. In particular, among the natural fibres (i.e. animal, vegetable or mineral) that can be used as reinforcement, the basalt ones represent the most interesting for their properties. The aim of this review is to illustrate the results of research on this topical subject. In the introduction, mechanical, thermal and chemical properties of basalt fibre have been reviewed. Moreover, its main manufacturing technologies have been described. Then, the effect of using this mineral fibre as reinforcement of different matrices as po…
Influence of uniaxial pressure and aging on dielectric and ferroelectric properties of BaTiO3ceramics
2013
The effect of uniaxial pressure (0–3000 bar) applied parallel to the AC electric field and aging on dielectric and ferroelectric behavior of BaTiO3 ceramics were investigated. Applying uniaxial pressure leads to a reduction of the peak intensity of the electric permittivity (e) of the polarization as well as of the dielectric hysteresis. The peak intensity of e becomes diffused and shifts to a higher temperatures with increasing the pressure. The electrostrictive coefficient Q 11 and differential permittivity were evaluated from the obtained data. We interpreted our results based on the hardening of the soft-mode and domain switching processes under the action of pressure. The aging effect …
Synthesis and properties of an Au6 cluster supported by a mixed N-heterocyclic carbene–thiolate ligand
2020
The preparation of a novel Au6 cluster bearing a bidentate mixed carbene–thiolate ligand is presented. The length of linker between the central benzimidazole and thiolate has a strong effect on the formation of cluster products, with a C2 chain giving an Au6 cluster, while a C3 chain results in no evidence of cluster formation. Density functional theory analysis predicts a non-metallic cluster with a large HOMO–LUMO (3.2–3.6 eV) and optical gap.
Halogen Bonded Analogues of Deep Cavity Cavitands
2014
The first examples of halogen bonded analogues of deep cavity cavitands with guest binding properties, formed between N-alkyl ammonium resorcinarene halides as acceptors and bromotrichloromethane as the donor, are reported in the solid state and in solution.
PLA graphene nanoplatelets nanocomposites: Physical properties and release kinetics of an antimicrobial agent
2017
Abstract Graphene nanoplatelets (GnP) as filler and ciprofloxacin (CFX) as biocide were incorporated via melt-compounding into poly(lactic acid) (PLA) to obtain biopolymer-based nanocomposites with antimicrobial properties. GnP were added with the aim of improving the mechanical properties of the antimicrobial system and tuning the drug release. The obtained systems were mechanically characterized in tensile mode by quasi-static and dynamic mechanical tests. Furthermore, rheological measurements were performed. The morphology of the samples was analyzed through scanning electron microscopy (SEM). Moreover, a mathematical model, i.e. power law model, was used to fit the release data in order…
Influence of a bioceramic root end material and mineral trioxide aggregates on fibroblasts and osteoblasts
2012
The biocompatibility of materials used in endodontic treatment is of high importance, because they can come in contact with periradicular tissues and there is a risk of possible systemic toxicity. The aim of the present study was to investigate the in vitro reaction to a bioceramic based root end material in comparison to mineral trioxide aggregates (MTA) as the established gold standard.The root end materials grey MTA Angelus (GMTA), white MTA Angelus (WMTA), ProRoot MTA, and EndoSequence Root Repair Material (ERRM) were incubated with human periodontal ligament fibroblasts and osteoblasts (10(4)cells/ml) for up to 96h. Cell proliferation (RFU) was determined by means of the Alamar Blue as…
Sensory hybrid host materials for the selective chromo-fluorogenic detection of biogenic amines
2006
[EN] Pyrylium-containing mesoporous materials have been used for the chromo-fluorogenic sensing of biogenic amines in an aqueous environment.