Abstract: The heel insert is an insert for an article of footwear, such as a shoe or a boot. The heel insert includes a main body member having an arcuate cross-sectional contour and defining a concave inner surface and a convex outer surface. The concave inner surface is adapted for contacting and supporting the wearer's heel, ankle and Achilles tendon, and the convex outer surface is adapted for contacting a rear, inner surface of the article of footwear. The main body member has opposed top and bottom ends, with an inwardly extending flange being formed on the bottom end. One or more recesses or notches are formed in the flange. The main body member is preferably formed from a high-density polyethylene hydrophobic material with a thickness of about 0.5 mm.

Abstract: In a method for the preparation of a melt for the production of mineral wool a raw material is introduced at the top of a shaft furnace and heated to melting temperature partly with a hot gas formed by plasma heating and partly with a hot gas formed by combustion of one or more gaseous hydrocarbons, the latter gas stream being introduced at a level at which the temperature does not exceed 1250.degree. C., and the melt formed is discharged at the bottom of the shaft furnace.

Abstract: Method of preparing a melt for the production of mineral wool wherein suitably composed raw material and coke are fed into a preheating zone in the upper portion of a shaft furnace and are caused to descend down through the oxidation zone in which air is introduced to effect a combustion of the coke and to heat the raw material to a temperature not exceeding 1000.degree. C., and wherein the actual melting is effected by plasma heating in the lower portion of the shaft furnace where which the melt formed is discharged.

Abstract: Alkali resistant, synthetic, mineral fibres having the following composition on weight basis: SiO.sub.2 : 42-50%, Al.sub.2 O.sub.3 : 8-13%, Iron oxides (calculated as FeO): 6-11%, CaO: 4-11%, MgO: 17-22%, TiO.sub.2 : 0.5-3% and alkali metal oxides: 0.5-3.5%.