Introduction: Presolar grains are particularly abundant in primitive extraterrestrial materials such as IDPs [e.g. 1-3] and the matrices of the least altered chondrites [4-6]. To date, the presolar silicate and oxide inventories of the primitive chondrites Acfer 094 [4-7] and ALHA 77307 [7] have been reported extensively. More recently, the search for presolar silicates and oxides has been exte...

Determining the Mn valence variation at nanometer scale will be an important advance in study of heterogeneous natural silicates. Here, potential scanning transmission X-ray microscopy L2,3-edges (640–655 eV) as a probe for manganese redox state is evaluated. For this purpose, several Mn-silicates (rhodonite, ardennite, piemontite, Mn4+-silicate, jacobsite) were analysed to identify spectral pa...

Over the past decades, efficiency of silicate-based surface treatment agents, in other words, sealers, concrete systems has been widely investigated. The technology protects cementitious against penetration undesirable substances. Nevertheless, understanding several aspects concerning sealers is not entirely clear. This paper studies action mechanism selected silicates such as potassium, sodium...