Search results for "CERAMICS"
showing 10 items of 1599 documents
Supramolecular Design of Low-dimensional Carbon Nano-hybrids encoding a Polyoxometalate-bis-Pyrene Tweezer
2014
A novel bis-pyrene tweezer anchored on a rigid polyoxometalate scaffold fosters a unique interplay of hydrophobic and electrostatic supramolecular interactions, to shape carbon nanostructures (CNSs)-based extended architectures.
Infrared Thermography assisted evaluation of static and fatigue Mode II fracture toughness in FRP composites
2019
Abstract The work proposes the combined use of a Modified Transverse Crack Tension (MTCT) test coupon and Infrared Thermography, to evaluate the static and fatigue behaviour of Fibre Reinforced Polymer composites under Mode II delamination. Artificial delaminations starters are added to the TCT coupon, whose effects on the Strain Energy Release Rate are discussed. Infrared Thermography and Thermoelastic Stress Analysis are implemented to investigate stresses and delaminations growths on two FRP materials: a pre-preg IM7/8552 carbon fibre-epoxy and a glass-fibre reinforced epoxy laminates. The thermographic, thermoelastic and second harmonic signals have been obtained and used to monitor the…
Structural performances of pultruded GFRP emergency structures – Part 1: Experimental characterization of materials and substructure
2019
Abstract This paper presents an experimental study in the field of structures made of pultruded fiber reinforced polymers (FRP) elements to be used for emergency purposes. A preliminary design of a 3D pultruded glass fiber reinforced polymer structure is presented with the mechanical characterization of the constituting elements. The axial and flexural properties of laminate and I-shaped GRFP profiles are discussed considering the short term creep. In a companion paper, the benefits, the limits and the reliability of the structure analyzed for emergency applications are discussed. In details, the numerical structural analysis of the full-scale 3D model is described followed by the experimen…
Synthesis, crystal structures, magnetic properties, and lattice dynamics of Ba2XCu(OH)[V2O7] with X=Cl, Br
2016
Abstract We have synthesized Ba2XCu(OH)[V2O7] with X=Cl, Br by hydrothermal methods. The isotypic structures (Pnma, Z=4, a≈15.1 A, b≈6.1 A, c≈9.6 A) contain distorted hexagonal layers of Ba and X in a BN-type arrangement. Each halide is further coordinated by one out-of plane Ba atom in an alternate up-down fashion resulting in an overall Ba 2 X 3 + ∞ 2 structural feature. The planar Ba–X hexagonal rings are centered by divanadate groups in an eclipsed orientation. Edge-sharing chains of CuO 2/2 (OH) 2/2 O 2/1 5 - ∞ 1 complement the structure. The magnetic properties are associated with the magnetic Cu2+ ions and can be described as an antiferromagnetic quasi 1D S=1/2 Heisenberg system. Co…
The wet synthesis and quantification of ligand-free sub-nanometric Au clusters in solid matrices.
2017
© The Royal Society of Chemistry. The synthesis of ligand-free sub-nanometric metal clusters on a large scale suffers typically from very low yields (15% yields, as unambiguously determined using a very simple and extremely sensitive analytical reaction test.
Design of cost-efficient and photocatalytically active Zn-based MOFs decorated with Cu 2 O nanoparticles for CO 2 methanation
2019
<div>Here we show for the first time a MOF that is photocatalytically</div><div>active for the light-assisted CO<sub>2</sub> methanation at mild conditions</div><div>(215 °C) without the inclusion of metallic nanoparticles or any</div><div>sacrificial agent. The presence of Cu<sub>2</sub>O nanoparticles causes a 50 % increase in the photocatalytic activity. These results pave the way to developping efficient and cost-effective materials for CO<sub>2</sub> elimination.</div>
Behaviour of thermal expansion of (1-x)Pb(Ni1/3Nb2/3)O3–xPbTiO3 solid solutions
2017
The publication costs of this article were covered by the Estonian Academy of Sciences and the University of Tartu.
Effect of silane coupling treatment on the adhesion between polyamide and epoxy based composites reinforced with carbon fibers
2020
The increasing efforts aimed to design structures with reduced weight and better mechanical performances has led in recent years to a growing use of fiber reinforced polymer materials in several fields such as marine. However, these materials can be composed of chemically very different elements and, hence, may be difficult to joint. This research aims to improve the adhesion between a thermoplastic matrix of polyamide reinforced with short carbon fibers (PA12-CR) and a carbon fiber reinforced epoxy matrix (CFRP). Two different silane coupling agents, (3-Aminopropyl)trimethoxysilane (AM) and (3-Glycidyloxypropyl)trimethoxysilane (EP), were applied, through the spray deposition method, on th…
Effects of aging in salt spray conditions on flax and flax/basalt reinforced composites: Wettability and dynamic mechanical properties
2016
Abstract In the last years, the industrial policies are more attentive to issues concerning sustainability, recycling and environmental care. Therefore, the use of natural fibres in composite materials has spread more and more. This paper deals with flax and basalt fibres within an epoxy matrix by investigating the wettability and the dynamic mechanical properties of the resulting composites, subjected to long-term aging tests in critical environmental conditions. The first laminate was constituted by stacking ten layers of bidirectional flax fabrics. The second one was produced by replacing two external flax layers with two layers of basalt mat, for each side of the laminate. Both laminate…
Experimental design of the bearing performances of flax fiber reinforced epoxy composites by a failure map
2018
Abstract This paper represents the first effort aimed to the investigation of the pin/hole contact stress and failure mechanisms of epoxy composites reinforced with woven flax fabrics, underwent to tensile bearing tests. In particular, the maximum loads and failure modes are evaluated at varying the laminate geometrical configuration. In order to optimize the use of polymer composites reinforced with flax fibers in structural applications, an experimental failure map, identifying main failure modes of mechanically fastened joints, is obtained as function of hole diameter, distance of the hole from the free edge of the laminate and laminate width. Moreover, a theoretical approach based on th…