Search results for "Agglomerate"
showing 10 items of 20 documents
Dense Mosi2 produced by reactive flash sintering: Control of Mo/Si agglomerates prepared by high-energy ball milling
2011
The objective of this work is to determine the influence of the agglomeration state of the MA mixture on the microstructure and the chemical composition of SPS end-products. In order to produce MoSi2 with a microstructure and a density perfectly controlled via reactive sintering implying an SHS reaction, the characteristics of Mo/Si mechanically activated (MA) powder mixtures were investigated. Indeed, the MA powders have been characterized in terms of their surface specific area, size, phase composition and microstructure. The high-energy milling allows the formation of agglomerates (0.8 to 800 μm) composed of nanometric crystallites of molybdenum and silicon, as a consequence of a continu…
Mechanical Behaviour of a Green Sandwich Made of Flax Reinforced Polymer Facings and Cork Core
2015
Abstract This work investigates the flexural behavior of a composite sandwich made of flax fibers reinforced skin facings and an agglomerated cork core, to be employed as an eco-friendly solution for the making of structural components of small sailing boats. An experimental mechanical characterization of the strength and stiffness flexural behavior of the proposed sandwich is carried out, providing a comparison of performances from three implemented assembling techniques: hand-lay-up, vacuum bagging and resin infusion. Sandwich beams have been tested under three point bending (TPB) at various span lengths. A procedure is also proposed and implemented to consider the potential influence of …
Morphology, interfacial interaction, and thermal degradation of polycarbonate/MCM-41 (nano)composites
2017
ABSTRACTThis article reports on the morphology, interfacial interaction, thermal stability, and thermal degradation kinetics of polycarbonate (PC)/mesoporous silica (MCM-41) composites with various MCM-41 contents, prepared by melt compounding. The composites with low filler loadings (<0.3 wt%) maintained their transparency because of the well dispersed MCM-41 particles, but at higher filler loadings the composites lost their transparency due to the presence of agglomerates. The presence of agglomerates decreased the thermal stability of PC due to the reduced effectiveness of the particles to immobilize the polymer chains, free radicals, and volatile degradation products.
A rapid and eco-friendly route to synthesize graphene-doped silica nanohybrids
2016
International audience; In the present study, the possibility to synthesize graphene oxide (GO)-based nanohybrids with pure and O2-doped silica nanoparticles by a rapid and easy hydrothermal process has been explored. The nanohybrids were prepared by varying the type of silica nanoparticles (average diameter 7 nm or 40 nm) and the silica/GO weight ratio. All the materials were fully characterized by spectroscopic and morphological techniques.The experimental results revealed that it is possible to tune the characteristics of the obtained nanohybrids, such as morphology and amount of ester/ether linkages upon varying the preparation parameters, together with the nanosilica's typology and the…
Formation of hierarchically ordered silicas prepared by spray drying of nanosized spheres
2002
We report on our strategy to synthesise defined arrangements of macro- and mesopores in one single material with spherical morphology using the spray drying technique. As starting materials, nano-sized silica spheres and colloidal suspensions were chosen. The intra-particle as well as inter-particle pore size was independently controlled which allowed to obtain materials with varied bimodal pore networks. The spherical agglomerates were characterised regarding their pore structural parameters and are potential adsorbents in liquid chromatographic separations.
Agglomerated non-porous silica nanoparticles as model carriers in polyethylene synthesis
2004
Abstract Non-porous submicron silica particles (250 and 500 nm) with high monodispersity were agglomerated to form spherical agglomerates via spray drying. As a binder, 25 nm sized monodisperse silica spheres were selected from a variety of colloidal systems including Levasil-type and Aerosil-type silica nanoparticles. The use of such binders led to an increase of the specific surface area of the agglomerated carriers. All materials were characterised by nitrogen sorption, mercury intrusion and scanning electron microscopy. The silica agglomerates, with highly defined geometrical and pore structural parameters, were employed as model carriers in the heterogeneous polymerization of ethylene …
New model describing the total dispersion of dry powder agglomerates
2010
Micron and submicron particles tend to form agglomerates due to adhesive and cohesive forces. The disintegration of these dry powder agglomerates often represents a major task in powder technology. One model describing the mechanical stability of granulates is given by the planar fracture model of Rumpf. In the present work, a new model is introduced intended for applications where a complete disintegration of dry powder agglomerates is required (e.g. for pharmaceutical aerosol generation). Therefore, the breakup of every single connection inside an agglomerate is considered and the dispersion strength σdisp of model agglomerates is calculated and discussed. In order to balance the stabilit…
Optical properties of TiO2 suspensions: Influence of pH and powder concentration on mean particle size
2007
WOS: 000250584100025
Effects of defects on the tensile strength of short-fibre composite materials
2014
Abstract. Heterogeneous materials tend to fail at the weakest cross-section, where the presence of microstructural heterogeneities or defects controls the tensile strength. Short-fibre composites are an example of heterogeneous materials, where unwanted fibre agglomerates are likely to initiate tensile failure. In this study, the dimensions and orientation of fibre agglomerates have been analysed from three-dimensional images obtained by X-ray microtomography. The geometry of the specific agglomerate responsible for failure initiation has been identified and correlated with the strength. At the plane of fracture, a defect in the form of a large fibre agglomerate was almost inevitably found.…
La formalisation fractale des tissus urbains
1998
The article concerns the fractal approach as it can bring new results making more understandable the morphology of agglomerate urban patterns. A new paradigm is developed, in order to improve the study of urban organizations according to optimization criteria. Specific fractal and multifractal methods are explicitated and applied to the knowledge of some big metropolitan areas and towns in Franche-Comté (France).