Abstract: A system for handling meta data for describing one or more resources, wherein the one or more resources are deliverable to a common group of users at one or more user terminals, the system including: a resource server for storing the one or more resources for delivery to at least one of the common group of users at one or more user terminals, an administration server arranged to serve the common group of users at the one or more user terminals, for storing a set of meta data for describing the learning resources, the meta data having a format including a non-semantic tag which is customizable in accordance with the common group of users' requirements.

Abstract: The invention relates to a composition and method for treating a magnesium alloy. The inventive composition comprises an acid aqueous solution containing niobium pentoxide, a water-soluble cerium salt and, optionally, a zirconium salt and/or hydroflouric acid. Said method consists in submerging a magnesium alloy part in said composition. The invention can be used to protect magnesium alloy parts against corrosion.

Abstract: The invention relates to a composition for treating magnesium alloys aimed at improving the resistance thereof to corrosion. The composition is an aqueous solution with a pH ranging between 7 and 10, containing a niobium salt, hydrofluoric acid, and optionally a zirconium salt, phosphoric acid, and boric acid. The alloy is treated in an electrochemical cell in which said alloy acts as an anode. The cell contains an inventive composition at a temperature between 20° C. and 40° C. as an electrolyte. An initial voltage which is sufficient to create a current density between 1.5 and 2.5 A/dm2 is applied to the cell, whereupon the voltage is progressively increased to a level ranging between 240 and 330 V in order to maintain the initial current density.

Abstract: The invention relates to a composition for treating magnesium alloys aimed at improving the resistance thereof to corrosion. The composition is an aqueous solution with a pH ranging between 7 and 10, containing a niobium salt, hydrofluoric acid, and optionally a zirconium salt, phosphoric acid, and boric acid. The alloy is treated in an electrochemical cell in which said alloy acts as an anode. The cell contains an inventive composition at a temperature between 20° C. and 40° C. as an electrolyte. An initial voltage which is sufficient to create a current density between 1.5 and 2.5 A/dm2 is applied to the cell, whereupon the voltage is progressively increased to a level ranging between 240 and 330 V in order to maintain the initial current density.

Abstract: The invention relates to a composition and method for treating a magnesium alloy. The inventive composition comprises an acid aqueous solution containing niobium pentoxide, a water-soluble cerium salt and, optionally, a zirconium salt and/or hydroflouric acid. Said method consists in submerging a magnesium alloy part in said composition. The invention can be used to protect magnesium alloy parts against corrosion.