Abstract: A device measuring air permeability of a building, including: an airtight duct, open at both its ends; a motorized fan; an air induction member positioned in the duct with its axis of rotation substantially parallel to a longitudinal axis of the duct; a mechanism measuring pressure difference between an inside of a part of the building and an outside of the building; an adjustable shut-off member shutting off the duct, and configured to vary locally cross section for air flow through the duct, the shut-off member being continuously adjustable between a configuration of minimal shutting-off of the duct and a configuration of complete shutting-off of the duct; and a mechanism determining a degree to which the duct is shut off by the shut-off member for a reference pressure difference determining, from the degree of shutting-off, either corresponding air flow rate through the duct, or a parameter representative of the air permeability.

Abstract: The invention relates to a transparent substrate comprising at its surface a grating of lines of at least 200 light-diffusing elements, said elements being separated by domains with a different refractive index from that of the elements, the distance d between centers of gravity of neighboring elements varying in a non-monotonic manner from one edge of the grating to the other, so that for any group of 50 successive elements, the distance d between the centers of gravity of neighboring elements of said group is at least once greater than and at least once less than the mean distance dm of distances d between centers of gravity of neighboring elements of said group, dm lying between 75 nm and 200 ?m. This substrate is transparent in direct vision and redirects the light while diffusing it without iridescence in a daylighting application.

Abstract: The invention relates to a transparent substrate comprising, on its surface, a light-diffusing array comprising at least 10 juxtaposed sub-gratings of parallel lines of features, said features being separated by domains with a refractive index differing from that of the features, each sub-grating comprising at least 20 repeated successive identical features equally spaced apart with a period p, said period varying non-monotonically from one edge of the sub-grating array to the other. This substrate redirects the light without iridescence in a daylighting application.

Abstract: The invention relates to a transparent substrate comprising, on its surface, a light-diffusing array comprising at least 10 juxtaposed sub-gratings of parallel lines of features, said features being separated by domains with a refractive index differing from that of the features, each sub-grating comprising at least 20 repeated successive identical features equally spaced apart with a period p, said period varying monotonically from one edge of the sub-grating array to the other. This substrate redirects the light without iridescence in a daylighting application.

Abstract: The invention relates to a transparent substrate comprising at its surface a grating of lines of at least 200 light-diffusing elements, said elements being separated by domains with a different refractive index from that of the elements, the distance d between centers of gravity of neighboring elements varying in a non-monotonic manner from one edge of the grating to the other, so that for any group of 50 successive elements, the distance d between the centers of gravity of neighboring elements of said group is at least once greater than and at least once less than the mean distance dm of distances d between centers of gravity of neighboring elements of said group, dm lying between 75 nm and 200 ?m. This substrate is transparent in direct vision and redirects the light while diffusing it without iridescence in a daylighting application.

Abstract: The invention relates to a process for structuring a surface, that is to say for forming at least one array of features with a submillimeter-scale lateral characteristic dimension on a plane surface of a product comprising a rigid glass element (1) and at least one layer (1a) attached to said glass element (1), the structuring being carried out on said layer (1a) and a surface structuring, by plastic or viscoplastic deformation, being carried out by contact with a structured element called a mask (10) with application of pressure, the structuring taking place by a continuous movement, parallel to the surface, of the product and by a movement of the mask about an axis parallel to the plane of the surface of the product. The invention also relates to a glass product having a structured surface and to its uses.