1,721,094 research outputs found
Powder flowability characterizing techniques
No full textThe experimentally determined indexes for describing the flow of behavior of powder streams in industrial storage, transport, and processing operations are discussed. A better control of powder flow during manufacturing optimizes the quality of the product in terms of uniformity and efficiency. Flowability is important in several industrial processes in the ceramic industry, where flowability of a spray-dried or a granulated powder, in the step of mold filling, affects the green-body homogeneity velocity after compaction. Flowability is also important in dry-powder decoration, a technique that will become much more used in the future, where the reproducibility and the precision of the drawing are strictly dependent on powder flowability.
Poly(methyl methacrylate)-TiO2 nanocomposite obtained by non-hydrolytic sol-gel synthesis
No full textPoly(methyl methacrylate) (PMMA)/titanium dioxide (TiO2) nanocomposites were prepared by means of in situ generation of TiO2 through a non-hydrolytic sol-gel process (NHSG), starting from titanium chloride, as titania precursor, benzyl alcohol, as oxygen donor, and commercial PMMA. TiO2 nanoparticles (average size of 30 nm) were obtained in the anatase and amorphous forms. The in situ generation led to a very homogeneous distribution of particulate fillers within the polymeric matrix avoiding the problems related to distributive and dispersive mixing of conventional compounding methods (top down approach). A slight increase of glass transition temperature was observed for all prepared composites with respect to the pristine PMMA. The NHSG process did not affect the molecular weight of the polymers indicating the absence of any degradation reaction for PMMA. The presence of titania in the anatase phase increases the photodegradation of the PMMA matrix due to UV irradiation. © Springer Science+Business Media, LLC 2011
Non-hydrolytic sol–gel synthesis and reactive suspension method: an innovative approach to obtain magnetite–epoxy nanocomposite materials
No full textAbstract: Innovative magnetite–epoxy nanocomposites were prepared starting from magnetite nanoparticles suspended in alcoholic or amino reactive solvents, synthesized by non-hydrolytic sol–gel process from iron (III) acetylacetonate. The obtained suspensions, also synthesized using microwave heating, were mixed with an epoxy monomer (bisphenol A diglycidyl ether, DGEBA), and the formulations were subsequently cured. The thermally activated ring-opening polymerization produced a three-dimensional network in which the suspending medium was covalently linked to the epoxy network according to the chain or step polymerization mechanisms during the cross-linking reaction. This synthetic strategy allowed to obtain nanocomposites in which the nanoparticles play an active role in the polymeric structure, affecting the structural (mechanical and thermal) and functional (magnetic) properties of the final system. The presence of magnetite nanoparticles in the composite resulted in distinct reinforcing effects, acting as rigid filler and/or as cross-linking point, depending on the different chemical environment at the nanoparticle–polymer interphase. Graphical Abstract: [Figure not available: see fulltext.
Neural network approach for colour matching of ceramic glazes
No full textAesthetical quality of ceramic tiles is a winning and indispensable requirement in production. Pigment oxides play an important role and more and more sophisticated applications are required in industrial applications. In the present work a neural network model was tested to define the final apparence due to the mixture of ceramic pigment used for wall tiles. Samples were prepared using 30 industrial pigments and one frit for wall tiles. Mixing the pigments, 79 samples were prepared in a fast ball mill and applied on tiles. After firing in a industrial cycle, the L*,a* and b* coordinates in CIElab spaces were measured using a spectrophotometer and put in relationship with the pigment compositions to define a model able to calculate the colour when the pigment composition is known. The results show a good efficiency of the color matching algorithm
Inorganic pigments for ceramic tiles: Characteristics and industrial applications
No full textThis paper aims at presenting an overview of recent trends in the industrial applications of inorganic pigments in the tile industry. Examples of applications of natural and synthetic inorganic pigments to colour-glazed and unglazed tiles at high temperatures are presented. The most important aspects concerning the physical and chemical properties of pigments, the design of new pigments and application of unconventional synthesis methods are discussed
Advanced materials & green processes for a sustainable society (INSTM Sestriere 2022)
No full textThis virtual special issue gathers a selection of articles following contributions presented at the XIII INSTM Conference on Materials Science and Technology, the yearly event that gathers the national community, which was held at the Olympic Village TH Hotel in Sestriere (Torino, Italy), built for the 2006 Winter Games, with panoramic views toward one of the most famous Europe's skiing resorts on the mountains of the north-west side of Italy
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
TiO2 nanocoatings for architectural heritage: Self-cleaning treatments on historical stone surfaces
Full text linkThe development and application of nano-engineered surface treatments on stones could become a useful tool for the realization of smart systems to better preserve and maintain architectural surfaces. Titanium dioxide nanoparticles can be used to realize transparent self-cleaning coatings applicable directly on preexisting surfaces, limiting cleaning actions and conservation processes, thus reducing their costs. The aim of this investigation is to evaluate the potential use of TiO2 on stone surfaces, especially in the field of architectural heritage. An aqueous colloidal dispersion based on titanium dioxide, obtained by sol-gel and hydrothermal processes, was applied by spray coating on travertine, a limestone largely used in buildings, both historical and modern. The maintenance in the original appearance of treated substrates was evaluated monitoring both colour and gloss changes produced by the treatments. Physical changes induced to stone by titanium dioxide were studied by wettability analyses. The efficiency of TiO2 photocatalysis was assessed by depolluting and soiling removal tests under ultraviolet light. The effects of deposited amount of titania on treated surfaces were also evaluated. Obtained results seem to allow the use of selected TiO2 treatments on the selected substrate, travertine, without altering in an evident and harmful way the original properties of limestone. Photoinduced effects (hydrophilicity, degradation of pollutants and decolourization of soiling) are very evident, and the combination of these properties may lead to an actual self-cleaning effect
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