In the secondary circuit of nuclear Pressurized Water Reactors, corrosion products and impurities lead to formation undesirable hard deposits, called sludge, on tube sheet steam generators. Theses deposits are mainly composed iron (magnetite), alumina silica. The sludge piles is investigated by reproducing reaction precursor oxides in conditions generator (275 °C, 58 bar). Mixtures magnetite, γ...

OBJECTIVES To evaluate the bonding of resin-cement to yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) via silica coating followed by silanization, and three one-bottle universal adhesives, with or without prior conditioning using a zirconia primer. METHODS Y-TZP specimens (n=160) were conditioned by tribochemical silica coating and silanization (CS), or alumina sandblasting with one...

Palladium doped silica membranes were synthesized by the sol-gel method using two different procedures. The first palladium-doped silica membrane (M1) was synthesized with a coating of four layers of silica-palladium sol. The second membrane (M2) was synthesized with a coating of two silica layers followed by a coating of two silica-palladium layers. Scanning electron microscopy (SEM) proved th...

Silica nanoparticles (NPs) belong to the industrially most important NP types. In a previous study it was shown that amorphous SiO(2) NPs of 12.5 and 27.0 nm are stable in algal growth inhibition assays and that their ecotoxic effects are related to NP surface area. Here, it was hypothesized and demonstrated that an alumina coating completely alters the particle-particle, particle-test medium a...

Abstract Porous mullite ceramics were prepared from mixtures of Egyptian kaolinite-clay and calcined α-alumina powder. The effects two methods compaction as well types binder investigated. influence sintering temperature on the physical properties, crystalline phase, compressive strength microstructure was studied. Mullite bodies processed by uniaxial pressing utilizing 15wt. % water at 1500°C ...

Background: Organochlorinated compounds are major environmental concern due to their persistence, long-range transportability and bio-accumulation. Chlorinated paraffin (CP) mixtures, especially short-chain CPs (SCCPs), are found in environmental samples at very high levels. However, information about their levels is still insufficient, mainly in marine biota. Methods: This study aimed to optim...

PTFE-based coatings have been widely used, for example, on aluminium moulds for moulding of polyolefin packaging materials for its non-stick property. However, these coatings do not meet the users’ scratch resistance and durability requirements. This paper describes a preliminary study on the synthesis and characterization of a PTFE/sol-gel composite coating material which combines the required...

In a physically confined environment, interfacial interactions, symmetry breaking, structural frustration and confinement-induced entropy loss can play dominant roles in determining molecular organization. Here we present a systematic study of the confined assembly of silica-surfactant composite mesostructures within cylindrical nanochannels of varying diameters. Using exactly the same precurso...

−− The main objective of this work is to study the feasibility of new materials to be used as support for boron-nickel catalysts. Potential support materials such as: silica gel, alumina, hydrothermal modified Perlites and zeolite 4A, were characterized by BET, TPR and DRX. After the addition of Ni and B, their catalytic activity evaluated with the nitrobenzene hydrogenation model reaction. The...