Abstract: A process for the preparation of tetrahydro-alpha-pyrones comprises preparing the alkyl ester of a 5-oxo alkanoic acid from a 4-oxo alkane carbonitrile, obtained in a first stage by the action of benzyl cyanide on the corresponding alkenone, and then saponifying the obtained ester, followed by hydrogenation and cyclization.

Abstract: A brake disc comprises two flat, parallel friction rings interconnected by radial and axial ribs, with each ring being formed by at least two joined sectors. A circular flange extends radially inwardly from the rings and has a shoulder for receiving the lip of a flexible cylindrical web extending concentrically back from one end of a central hub. The flange and lip are secured together by a plurality of screws which bear the braking forces, while the flexibility of the web accommodates radial expansions due to the heating of the friction rings.

Abstract: 6-Methyl-3,4-diphenyl-3,4,5,6-tetrahydro-2-pyrone or derivatives thereof are psychostimulants which can be administered orally, parenterally and rectally. An effective oral dose for an adult is 100-1000 mg/day.

Abstract: The assembly is of the type in which the disc has a braking surface for cooperation with a brake pad and the wheel has a radially-extending web and an axial annular surface. A centering device centers the disc relative to the axial annular surface. The disc has on the side thereof opposed to the braking surface a second surface which frictionally engages a third surface defined by the wheel of the web. The second or third surface is constituted by a material having a coefficient of friction on the third or second surface which is higher than that of the braking surface of the disc on the brake pad so that, upon braking, the disc does not slip relative to the wheel.