Abstract: A method is described for the treatment of ferrous nuclear waste, produced in operations of pickling of contaminated metallic surfaces, which makes it possible to minimize the volumes of liquid phases to be treated and to recycle the by-products thereof to the process.

Abstract: A method is described for the treatment of ferrous nuclear waste, produced in operations of pickling of contaminated metallic surfaces, which makes it possible to minimize the volumes of liquid phases to be treated and to recycle the by-products thereof to the process.

Abstract: An optical article, having an almost complete isotropy and dimensions equal to or lower than 500 .mu.m, is prepared by a sol-gel procedure comprising a preliminary step wherein the mould is filled cold with a sol containing the desired oxide precursors, sol gelation, gel drying, removal of the gel from the mould and the subsequent miniaturization of the dried gel. The optical article can be used for optic telecommunications.

Abstract: Process for the preparation and the deposition of vitreous films on substrates comprising: the dissolution of one or more metal alkoxides in aprotic solvent, the hydrolysis of the resulting solution, the eventual removal of the formed alcohol, the deposition of the resulting sol on the substrate surface of interest and the final drying of the film.

Abstract: This invention concerns an agglomeration of particles to be used as additives for moulding thermoplastic polymers or paints, said agglomeration being in the form of chips, flakes, powder or paste in which a coating with a carrier of said particles is provided that moves in between the particles to keep them essentially separate from one another, said particles being substantially coated all over their surface.

Abstract: Pelletized silica particles characterized by a round shape and a monomodal particle size distribution are produced by dispersing silica particles into water, adding water to the dispersion, mixing with alkoxisilane, pouring the mixture into an organic solvent, filtering and washing the silica particles obtained. The pelletized silica particles can be used to produce glass monoliths.

Abstract: Sol-gel process comprising preparation of a solution of at least one compound having the formula Xm-M-(OR)n-m addition to the solution of the dopants, hydrolysis of the compound to form the sol, possible addition of an oxide, gelling the sol, recycling the liquid and adjusting the pH-value of the liquid in order to fix the dopants in the aquagel, gel drying and densifying to obtain the glass.

Abstract: Sol-gel process for the production of large glass monoliths, whereby tetraalkoxysilane is added to a dispersion of pyrogenically produced silica and the ratio of SiO2:TEOS is 2.6 to 5.5:1.

Abstract: A sol-gel process for the manufacture of moulds for use in photocatalysis. The process also relates to industrial pultrusion, extrusion and moulding processes in which use of moulds manufactured using the sol-gel process. The process provides for the provision of a sol which is gelled, drying of the gel with solvent extraction and then densification/sintering of the gel by heating with the formation of a transparent mould having a glassy consistency which is capable of permitting the passage of UV rays.

Abstract: An optical article, having an almost complete isotropy and dimensions equal to or lower than 500 .mu.m, is prepared by a sol-gel procedure comprising a preliminary step wherein the mould is filled cold with a sol containing the desired oxide precursors, sol gelation, gel drying, removal of the gel from the mould and the subsequent miniaturization of the dried gel. The optical article can be used for optic telecommunications.

Abstract: It has been discovered that aquagels, formed from acid catalized composite sols, survive to conditions of high-tension when they are prepared by a process that hydrolyzes the silicon alkoxides in presence of fumed silica. The aquagel can be used for the production of monoliths of glass.

Abstract: An optical article, having an almost complete isotropy and dimensions equal to or lower than 500 ?m, is prepared in which the sol-gel procedure comprises a preliminar step wherein the mould is cool filled with a sol containing the interesting oxide precursors, the sol gelation, the gel drying, the removal of gel from the mould and the final miniaturization of the dried gel. The optical article can be used for optic telecommunications.

Abstract: A method for the preparation of aerogels that involves the exchange of the liquid present in the aquagel with xenon and the subsequent extraction thereof.

Abstract: This invention concerns a method for flatting moulded thermoplastic polymers pieces, with this flatting being obtained by means of a mechanism for reflecting/refracting light on the surface achieved by adding particles used to create a specific geometric pattern on the surface of the moulded piece. Said method comprises the addition of particles to said thermoplastic polymers and is characterised by the fact that said particles to be added to the thermoplastic polymers are coated with a carrier that has a melting point that is lower than the melting point for said thermoplastic polymers and paints.

Abstract: The present invention relates to glassy inorganic films, characterized by a high chemical stability and a high adhesion, containing, among the others, titanium dioxide, employable to coat metal surfaces characterized by the presence of oxides, particularly stainless steel sheets. The coated structures obtained thereby, which are the second object of the present invention, are used to build many articles such as pipes, reactors, exchangers, containers, and so on. With reference to the peculiar case of stainless steel structures coated by the above film, these ones can be used in the food industry since that film coated article shows specific and very high photobactericide properties.

Abstract: It is described a sol-gel process that allows to obtain dry gels, and possibly the corresponding dense glassy bodies, having higher dimensions compared to similar known processes.

Abstract: Glassy articles are prepared by subjecting to hydrolysis and policondensation a solution or suspension of a suitable precursor, mainly comprising a silicon alkoxide, and by drying the obtained gel in a pressure chamber, the gel solvent having been substituted by a non-protic solvent, mainly acetone, under nitrogen flowing, at temperature and pressure conditions lower than the gel solvent critical values. The dried gel is then densified by a thermal treatment.

Abstract: Sol-gel-process to prepare aerogels comprising the preparation of a solution of a compound having the formula Xm-M-(OR)n?m, the hydrolysis of the compound to give a sol, gelation, drying, densifying and sintering. This method can be used to treat radioactive residues constituted by aqueous solutions of radioactive substances.

Abstract: An optical article, having an almost complete isotropy and dimensions equal to or lower than 500 ?m, is prepared by a sol-gel procedure comprising a preliminary step wherein the mould is filled cold with a sol containing the desired oxide precursors, sol gelation, gel drying, removal of the gel from the mould and the subsequent miniaturization of the dried gel. The optical article can be used for optic telecommunications.

Abstract: It is described a process based on sol-gel chemistry suitable to the production of nanocomposite materials being photoluminescent at ambient temperature, comprising silicon grains of dimension of nanometers embedded in a silica matrix.