Abstract: The invention concerns a method for qualifying a diamond on the basis of a measured light transmission through the diamond, whereby the diamond is radiated by a light source which emits light having a wavelength in a range of 225 nm to 300 nm, whereby the transmission of said light through the diamond is compared to a reference value which corresponds to the transmission of said light through a reference diamond, which is a cut colourless or near colourless diamond with a concentration of A centers between 7 ppm and 22 ppm, and whereby the diamond is classified as natural and not colour-treated if the transmission through the diamond is smaller than or equal to the reference value.

Abstract: Natural diamonds can be discerned from imitations, synthetic diamonds and treated diamonds on the basis of their physical qualities. Labs always test several specific characteristics in order to discern natural diamonds from others. One of the tested qualities is electrical conductivity. The invention concerns a method to establish the presence of electrical bulk conductivity. Use is made to this end of the fact that the proximity of an electrically conductive object (gemstone) has an influence on the parasitic capacity of a capacitive probe. The parasitic capacity is also influenced by the dielectric constant of the dielectric. The influence of the proximity of electrically conductive gemstones as opposed to non-conductive gemstones on the parasitic capacity is hereby larger than the influence of the differences in the dielectric constant of the gemstones.

Abstract: The invention concerns a method for qualifying a diamond on the basis of a measured light transmission through the diamond, whereby the diamond is radiated by a light source which emits light having a wavelength in a range of 225 nm to 300 nm, whereby the transmission of said light through the diamond is compared to a reference value which corresponds to the transmission of said light through a reference diamond, which is a cut colourless or near colourless diamond with a concentration of A centres between 7 ppm and 22 ppm, and whereby the diamond is classified as natural and not colour-treated if the transmission through the diamond is smaller than or equal to the reference value.

Abstract: The invention proposes a process for producing a component comprising a tubular body made of a thermoplastic, consisting of at least one elbow section, which process includes the steps of: a) a step of producing a tubular extrudate by extrusion or by injection; b) a step of forming the said elbow section by the hot bending of an intermediate section of the extrudate between two straight sections, characterized in that the bending step is carried out continuously on the hot extrudate formed during the production step. The invention also proposes an installation for implementing the process, which comprises a device for producing the extrudate by extrusion or injection, and a bending head placed immediately downstream of the production device.

Abstract: The invention proposes an arrangement for connecting a rigid tube to a flexible tube, of the type in which an upstream end section of the rigid tube is pushed coaxially into a complementary downstream end section of the flexible tube, and of the type which comprises a tubular sleeve which extends coaxially around the downstream end section of the flexible tube and is crimped radially onto the flexible tube to fix the rigid tube to the flexible tube by radial clamping, characterized in that the sleeve and the upstream end section of the rigid tube are curved at least in part and with more or less the same radius of curvature.

Abstract: Natural diamonds can be discerned from imitations, synthetic diamonds and treated diamonds on the basis of their physical qualities. Labs always test several specific characteristics in order to discern natural diamonds from others. One of the tested qualities is electrical conductivity. The invention concerns a method to establish the presence of electrical bulk conductivity. Use is made to this end of the fact that the proximity of an electrically conductive object (gemstone) has an influence on the parasitic capacity of a capacitive probe. The parasitic capacity is also influenced by the dielectric constant of the dielectric. The influence of the proximity of electrically conductive gemstones as opposed to non-conductive gemstones on the parasitic capacity is hereby larger than the influence of the differences in the dielectric constant of the gemstones.