Abstract: A sprocket comprising at least one groove for engaging a toothed belt, said groove having a flank, the flank having a groove tip radii (R1) of between approximately 105% and approximately 125% of a belt tooth root radii (R8) when the toothed belt is in rack form, said groove tip radii being joined to a groove arcuate conjugate flank portion (200) by a linear flank portion (202), and said linear flank portion being disposed at an angle (?) of between approximately 18° to approximately 24° with respect to a groove centerline (CL) and comprising a length of at least approximately 20% of a sprocket groove depth (h).

Abstract: A sprocket comprising at least one groove for engaging a toothed belt, said groove having a flank, the flank having a groove tip radii (R1) of between approximately 105% and approximately 125% of a belt tooth root radii (R8) when the toothed belt is in rack form, said groove tip radii being joined to a groove arcuate conjugate flank portion (200) by a linear flank portion (202), and said linear flank portion being disposed at an angle (?) of between approximately 18° to approximately 24° with respect to a groove centerline (CL) and comprising a length of at least approximately 20% of a sprocket groove depth (h).

Abstract: A mineral wool-free acoustical tile composition and the acoustical tile made therefrom wherein an expanded perlite is used as a substitute for granulated mineral wool to provide porosity and good sound absorption properties. It is preferred that the composition and acoustical tile also contain an inorganic filler to provide texturability during the manufacturing process. In addition, the acoustical tile composition also contains a starch gel binder and a fiber reinforcing agent selected from the group consisting of cellulosic fibers, polymeric fibers and glass fibers. It has been found that the mineral wool-free acoustical tile compositions of this invention have acoustical properties comparable to the commercially available cast mineral wool tiles. In addition, the mineral wool-free compositions can be used to cast an acoustical tile using equipment and procedures currently used to produce cast mineral wool tiles.

Abstract: A process for economically producing tabular acicular gypsum crystals in a continuously stirred reactor is disclosed. The process involves establishing a steady state atmospheric pressure reaction zone of about 20% to about 25% by weight solids of gypsum crystals in water at a temperature of about 50.degree. C. to about 60.degree. C. with continuous mild agitation. Calcium sulfate hemihydrate is fed to the reaction zone at a rate to maintain a low level of supersaturation, and a suspension of gypsum crystals in water containing crystals of a mean particle length at least greater than 45 microns is withdrawn.

Abstract: A tabular variety of acicular gypsum crystal filler is prepared by hydrating calcium sulfate dihydrate particles in a seeded continuously stirred reactor at a low level of super-saturation to obtain crystals having an aspect ratio of about 100:10:1 and average length in the longest dimension of about 100-450 micrometers. For the manufacture of paper, the obtained tabular crystal slurry may be directly added to the paper pulp before web formation to obtain a filled paper having high filler retention.

Abstract: A flexible power transmission belt having a plurality of teeth each of which has a pair of arcuate convex flank portions which in longitudinal cross-section closely approximate to an arc of a circle. Each tooth exhibits a height to width relationship within a predetermined range, and the arcuate flanks each have a pressure angle within a predetermined range. The belt is preferably used in combination with a toothed pulley whose teeth are substantially conjugate to the belt teeth and whose cavities between the teeth have a height to width relationship within another predetermined range and have concave flanks exhibiting a pressure angle in still another predetermined range, said belt tooth width being approximately 0.98 of the pulley cavity width so as to provide a high torque positive drive power transmission system having minimum backlash.

Abstract: Solidification of colloidal argillaceous matter in essentially non-settling, aqueous slime media into a solid stable matrix is accomplished by mixing such slime with a hydratable calcium sulfate and hydrating to form an interlocking strength bearing matrix. The method is particularly useful for coalescing phosphatic clay slimes with hydratable calcium sulfate prepared from the co-produced waste phosphogypsum.

Abstract: A wet process for producing phosphoric acid and phosphoanhydrite by acidulation of phosphate rock with a phosphoric acid/sulfuric acid mixture containing a very high recycle content of small sized anhydrite seed crystals. A strong phosphoric acid is obtained having a concentration of at least about 35% P.sub.2 O.sub.5. Further, the phosphoanhydrite may be readily converted to an industrially usable gypsum product.

Abstract: A wet process for producing phosphoric acid and phosphohemihydrate by acidulation of phosphate rock. A strong phosphoric acid is obtained with concomitant production of an improved calcium sulfate that is extremely low in radioactivity by operation in Region II for shorter time so as to produce small sized hemihydrate particles, then hydration of a substantial proportion but less than all of the hemihydrate to coarse gypsum substantially free of radioactivity in a dilute acidic aqueous slurry at a temperature and P.sub.2 O.sub.5 concentration selected so as to be within Region I of FIG. 1 and having a substantial weight proportion of coarser gypsum particles that are substantially free of radioactivity.

Abstract: A process for reducing radioactive contamination of phosphogypsum. Phosphogypsum containing radioactive material is calcined to form hemihydrate crystals carrying the radioactive contaminants, and a portion of the crystals is converted to substantially radiation-free gypsum crystals which are readily separated from the hemihydrate crystal relics containing substantially all of the radioactive contamination.

Abstract: A process for making an industrially usable gypsum from fluoroanhydrite in which fluoroanhydrite is contacted with a fluid reaction medium slurry containing soluble sulfate ions and a substantial proportion of small gypsum seed crystals to rapidly hydrate a large proportion of the fluoroanhydrite to a coarser, substantially pure gypsum. The slurry is clarified to separate coarse purified gypsum reaction product, and the reaction medium is reconstituted and recycled containing gypsum crystals less than the desired reaction product size and constituting about 50-90% of the total solids of the reconstituted fluid reaction medium.

Abstract: A process of two crystallization stages for reducing radioactive contamination of phosphogypsum is disclosed. In the process anhydrite crystals are obtained through dehydration of the radiation containing phosphogypsum in strong sulfuric acid; a portion of the anhydrite crystals containing the radioactive contamination is converted to substantially radiation free gypsum by crystallizing out on a large solids concentration of radiation free gypsum seed crystals; and coarse radiation free gypsum crystals are separated from small anhydrite crystal relics containing substantially all of the radioactive contamination.