Search results for "Composite"
showing 10 items of 4584 documents
Ferroelectric Liquid Crystalline Elastomers
2002
Ferroelectric LC-elastomers represent an interesting class of material because they combine the ordering of liquid crystalline ferroelectric phases and the rubber elasticity of polymer networks. Switching of the electric polarization leads to deformation of the polymer network, equivalent to stretching a spring, and creates a stress in the network of polymer chains. The interaction of mesogens and the network can be varied by using different topologies of net points: Crosslinking is carried out either within the siloxane sublayers (leading to fast switching elastomers) or between the siloxane sublayers (resulting in an elastomer that favors the ferroelectric switching state in which the cro…
Electrochemistry of iron oxide pigments (earths) from pictorial microsamples attached to graphite–polyester composite electrodes
2001
The electrochemical response of different iron pigments attached to graphite–polyester composite electrodes is described. Characteristic differential pulse voltammetric profiles were obtained for green earth, iron oxide red, Mars black, ochre yellow, Sienna raw, umber raw and Van Dyke brown. Proton-assisted reductive dissolution processes occur at the three-phase boundary of the substrate electrode–attached solid–electrolyte solution system. Microsamples extracted from polychromed sculptures, canvas paintings, wall paintings, altarpieces and panel paintings from Spain, Ethiopia and Italy from the 12th to the 20th centuries were electrochemically identified in agreement with polarized light …
High activity mesoporous copper doped cerium oxide catalysts for the total oxidation of polyaromatic hydrocarbon pollutants
2012
The doping of mesoporous ceria with copper significantly enhances activity for naphthalene total oxidation, the enhanced performance is controlled by the increased concentration of surface oxygen defects.
Water-insoluble β-cyclodextrin–epichlorohydrin polymers for removal of pollutants from aqueous solutions by sorption processes using batch studies: A…
2017
This review is dedicated to Giangiacomo Torri (Istituto di Chimica e Biochimica G. Ronzoni, Milan, Italy) in celebration of his retirement.; International audience; Although water-insoluble cyclodextrin-epichlorohydrin polymers have been known for half a century, these materials are of continued interest to the scientific community, in particular for their interesting environmental applications as sorbents in liquid-solid sorption processes. However, in spite of the abundance of literature and conclusive results obtained at the laboratory scale, interpreting the mechanisms of pollutant elimination remains an interesting source of debate and sometimes of contradiction. This review summarizes…
Highly selective and sensitive chromo-fluorogenic detection of the Tetryl explosive using functional silica nanoparticles
2011
Silica nanoparticles containing polyamines and thiol groups have been used as probes for the selective detection of Tetryl. © 2011 The Royal Society of Chemistry.
Design and use of a Fatigue Test Machine in Plane Bending for Composite Specimens and Bonded Joints
2011
Polymeric and composites materials are increasingly used in industry as structural parts, so that specific information on their mechanical properties "at long term" (creep, relaxation, fatigue) are requested. The design and implementation of these components also requires that they are permanently connected together to perform certain functions. The use of adhesives in structural joints has increased over recent years thanks to the continuous development by companies which provide the market with adhesive having better and better mechanical properties. The main areas relate to the aerospace, aeronautical and automotive industries, where requirements are required for lightness and reliabilit…
Acoustic Emission Monitoring of Chemically Bonded Anchors
2010
This paper presents a study on the use of acoustic emission (AE) to assess the structural soundness of concrete reinforced with chemically bonded anchors. The results of an experimental work based on six pullout tests monitored using an AE instrumentation suite are reported below. In every test one rebar was embedded in the hardened concrete by means of polyester resin. The AE was adopted to moni- tor the onset and progression of any structural damage. The parametric analysis, the intensity analysis and the moment tensor analysis of AE data were used to discriminate among different sources of damage. The technique shows promise for field application and may contribute to fully understand th…
Effects of Moisture and Stresses on the Structure and Properties of Polyester Resin
2004
The results of a complex study of structural changes in a cured Norpol 440 polyester resin under the action of damp environment and mechanical loading are presented. A considerable effect of absorbed moisture on the structure and some characteristics of the material is revealed by using thermophysical methods and X-ray diffractometry. The joint effect of moisture and mechanical stress is estimated by investigating the creep in stationary and nonstationary moisture conditions. The anisotropy of the material structure formed during creep is evaluated from the results of dilatometric measurements. It is found that the degree of anisotropy of the material after creep accompanied by moisture sor…
An investigation of the influence of the macroscopic heterogeneity on the thermoelstic response of fibre reinforced plastics
2005
In this work the influence of the inherent heterogeneity in fibre reinforced plastic composites on the qualitative and quantitative evaluation of the thermoelastic signal is discussed. The role of two different levels of heterogeneity is identified, distinguishing between a micro-geometric scale characterized by the presence of different constituent materials, and a macro-geometric scale characterized by a non-uniform distribution of these constituents. Attention has been focused on the macro-scale level, presenting results of experiments performed on glass fibre - polyester resin samples, intended to highlight the influence on the thermoelastic signal of the fabric texture pattern and the …