Abstract: A tool for forming parting grooves in a flat, plastically deformable workpiece, especially a continuously cast steel slab in a manner which seals the internal porosity of the slab in the regions which become exposed upon division, has a working portion in the form of a ridge which is most preferably in the form of a circumferential flange on a roll; and the cross-sectional shape of the ridge or flange is that of a highly convex tip between two gently convex side faces, and optionally, or essentially if either or both of the tip and the side faces are instead straight, the angle at which the side faces are mutually inclined is 20.degree. to 60.degree., the width of the tip is a given porportion of the thickness of the workpiece, and the width of the tip is specifically related to the said angle of inclination of the side faces. The height of the side faces, and their curvature and that of the tip, are also preferably within set limits.

Abstract: A photochromic glass/plastic laminated lens of improved physical durability comprising a buried layer of photochromic glass, surface layers of optically clear plastic, and adhesive bonding layers of high strength but low elastic modulus between the buried glass and plastic surface layers, is described.

Abstract: In the production of all-carbon composite articles by the cracking of a hydrocarbon gas to deposit carbon on a fibrous carbon substrate the substrate is held in the furnace by a ram movable in the furnace to engage the substrate. The gas is introduced inside the annular substrate and evacuated at a position spaced laterally from the substrate so that the gas is forced to disperse through the substrate wall.

Abstract: A vinylsulphone compound of the formula ##STR1## is provided. This compound is useful as cross-linking agent for hydrophilic colloids, especially for gelatin which is in the form of layers of photographic materials.

Abstract: In the production of all-carbon composite articles by the cracking of a hydrocarbon gas to deposit carbon on a fibrous carbon substrate the substrate is held in the furnace by a ram movable in the furnace to engage the substrate. The gas is introduced inside the annular substrate and evacuated at a position spaced laterally from the substrate so that the gas is forced to disperse through the substrate wall.

Abstract: In the process wherein 4,4,5-trimethyl -1,3-dioxane is contacted with aqueous acid to produce pinacolone, the improvement which comprises effecting the contact in the presence of 2-methyl-but-2-ene, whereby the yield of pinacolone is increased. Advantageously the 2-methyl-but-2-ene is present in approximately equimolar amount with the 4,4,5-trimethyl-1,3-dioxane and the acid is HCl of about 30 to 40% concentration or HBr of about 30 to 50% concentration.

Abstract: In the methylation of 4-amino-6-t.-butyl-3-mercapto-1,2,4-triazin-5-one to produce 4-amino-6-t.-butyl-3-methylmercapto-1,2,4-triazine-5-one using methyl bromide, the reaction is run in the absence of air whereby product coloration is avoided. Desirably considerable agitation is employed along with recycle and especially with an emulsifying agent which markedly speeds up the reaction. Measures such as operating under a slight vacuum and recycle of unused methyl bromide and mother liquor are employed to improve the yield and to avoid the problems of discharging the bromides to the environment.

Abstract: A magnetically operated display element comprises a disc of substantially non-magnetic material, provided on opposite sides with ears extending transversely in the same direction relative to the disc, said ears being designed to allow the pivotal mounting of said disc on supporting means. The disc is contrastingly colored on opposite surfaces and shaped so that concavities are provided as viewed on one of said surfaces, such concavities being on opposite sides of and defining on the surface on which they appear a ridge extending across said disc approximately parallel to the pivotal axis of the disc; the concavities and ridge appearing on the opposite surface as convexities and a valley.

Abstract: A middle tape punched to receive magnets is provided first with a tape on one side then with magnets in the punched apertures and then with a tape on the other side to provide a source of a series of magnetically actuable elements.