Search results for "CERAMICS"
showing 10 items of 1599 documents
Dibenzocycloheptatriene as end-group of Thiele and tetrabenzo-Chichibabin hydrocarbons
2020
The authors are grateful for the financial support from: MICIU/FEDER/AEI, Spain (PG2018-101181-B-I00, PGC2018-095808B-I00, MAT2016-80826-R, FIP-2018-HECTIC-PTM, Prometeo2019/076 and the "Severo Ochoa" Programme for Centres of Excellence in R & D; SEV-2015-0496), the European Research Council (ERC) (677023), DGR (Catalunya) (2017-SGR-918), and SNSF (Switzerland, TS., PZ00P2_174175). We thank the CSIRC-Alhambra and SciCore (Basel, Switzerland) for supercomputing facilities and the Servei de RMN, UAB, for instrument time.
A beam finite element for magneto-electro-elastic multilayered composite structures
2012
Abstract A new finite element based upon an elastic equivalent single-layer model for shear deformable and straight magneto-electro-elastic generally laminated beam is presented. The element has six degrees of freedom represented by the displacement components and the cross-section rotation of its two nodes. The magneto-electric boundary conditions enter the discrete problem as work-equivalent forces and moments while the electro-magnetic state characterization constitutes a post-processing step. The element possesses the superconvergence property for the static problem of beams with uniform cross-section and homogenous material properties along the beam axis direction. Moreover, it is free…
Effect of sodium bicarbonate treatment on mechanical properties of flax-reinforced epoxy composite materials
2017
This paper deals with the evaluation of the effect of an eco-friendly and cost-effective surface treatment based on the use of sodium bicarbonate on the mechanical properties of flax-reinforced epoxy composites. To this aim, unidirectional fabrics were soaked for five days in 5 and 10% in weight of sodium bicarbonate solution at 25℃. Quasi-static and dynamic mechanical tests were performed and the fracture surfaces of the composites were analyzed through scanning electron microscopy. Results evidenced that this treatment improves the fiber–matrix adhesion thus increasing the performances of the composites. Treating the fabrics with 10% w/w of bicarbonate solution leads to improvements of ∼…
Fast-growing willow (Salix viminalis) as a filler in polyethylene composites
2018
Abstract The study investigated the possibility of using wood flour obtained from fast-growing willow chips (Salix viminalis) as an alternative for standard hard- and softwood flours used in the production of wood polymer composites (WPCs). The composites contained willow flour and polyethylene matrix (OPCs) were prepared, characterized and compared with other WPCs which had been filled with hard- or softwood flours. Moreover, the structural and functional properties were investigated and discussed. Greater hemicellulose contents and lower lignin contents in OPCs resulted in better impact strength values of those materials. Which is interesting, the chemical composition of OPCs was found si…
Synthesis and optical characterization of Er-doped bismuth titanate nanoparticles grown by sol-gel hydrothermal method
2017
Abstract The Er 3+ -doped bismuth titanate (Bi 4 Ti 3 O 12 , BIT) nanoparticles were synthesized by a combined sol–gel and hydrothermal method under a partial oxygen pressure of 30 bar. The composition and morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman scattering. They showed pure and homogeneous spherical BIT nanoparticles with a size below the 30 nm. The incorporation of Er ions showed a strong decrease in the lattice parameters, as well as averaged particle size. The photoluminescence up-conversion (excitation wavelength =1480 nm) showed an enhancement of the infrared emission (980 nm) as Er concentration increased, achieving a maxi…
State selective electron injection in non-aggregated titanium phthalocyanine sensitised nanocrystalline TiO2 films
2004
We describe a novel titanium phthalocyanine that shows no aggregation when anchored to nanocrystalline TiO2 films through its axial carboxylated ligand without the use of co-adsorbents; state selective electron injection into the TiO2 is demonstrated, resulting in efficient photocurrent generation in dye sensitised photoelectrochemical solar cells. Palomares Gil, Emilio J, epagil@alumni.uv.es
Production and properties of doped PSN electro-optical ceramics
1997
Due to multifunctionality the transparent ferroelectric ceramics is attractive to solid state chemistry and physics as a promising material for active electro-optic elements. To study doping effects on the technological processing and properties, ceramic samples of Pb1-xZxSc1/2Nb1/2O3, have been prepared, where Z: (1) Ba (0 less than or equal to x less than or equal to 1), (2) rare-earth elements: Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu (x equals 0.1), (3) PbSc1/2Nb1/2O3 doped with 5 wt.% of rare-earth oxides. Ceramic characteristics, dielectric and electro-optical parameters have been measured. Differential thermal analysis (DTA), and x-ray diffraction are used to study the infl…
Halogen bonding drives the self-assembly of piperazine cyclophanes into tubular structures.
2009
Halogen bonding with 1,4-diiodotetrafluorobenzene leads to the self-assembly of piperazine cyclophanes into well-defined tubular structures with solvent inclusion.
Polymer-Functionalised Nanograins of Mg-Doped Amorphous Calcium Carbonate via a Flow-Chemistry Approach
2019
Calcareous biominerals typically feature a hybrid nanogranular structure consisting of calcium carbonate nanograins coated with organic matrices. This nanogranular organisation has a beneficial effect on the functionality of these bioceramics. In this feasibility study, we successfully employed a flow-chemistry approach to precipitate Mg-doped amorphous calcium carbonate particles functionalized by negatively charged polyelectrolytes&mdash
Effect of UD carbon on the specific mechanical properties of glass mat composites for marine applications
2009
In this work the influence of a uniaxial carbon fabric layer on the mechanical performances of a glass mat/epoxy composite used for marine applications has been studied. All the structures have been made, at room temperature, by vacuum bagging technique. Tension and flexural tests have been carried out in order to evaluate the specific mechanical properties of the composite and to compare these with those of the marine aluminium alloy 6016-T4. The glass composites have higher specific strength but lower specific modulus than aluminium alloy. To increase the specific modulus of the composites, each layer of glass mat has been replaced with a layer of uniaxial carbon fabric. In addition, a s…