Abstract: A perio-dontal surgical instrument is disclosed which includes a handle, shank and a cutting head. The cutting head possesses two interior surgical blades each possessing terminus points having their confluence at a substantial V-shape to form an apex. At least one exterior surgical blade is positioned on the cutting head with its beginning at a first point substantially equal to the terminus of one of the adjacent blades. A method of use is also described for this perio-dontal surgical instrument for Gingivectomy and Gingivoplasty operations.

Abstract: A forced circulation evaporator and method of use is disclosed that make use of a rotating impeller to both circulate liquid past the heating surface of the evaporator and to effect separation of liquid from vapor. A plurality of passage tubes acts as a generator of a liquid-vapor mixture. The impeller provides centrifugal force vectors to propel the liquid entity against the side wall of the separation zone to thereby leave the vapor to egress from the separation zone at a point near the axis of said impeller. Thus, the centrifugal force acts upon the varying densities of liquid versus vapor to cause separation more rapidly than under the mere influence of gravity.

Abstract: An improved structure adapted for undersea construction is described comprising a plurality of foundation blocks, each foundation block comprising a rectahedral parallelepiped opposite faces of which are concave and convex, respectively, the opposite faces being sized and shaped to interengage matingly, such foundation blocks being interfitted into a three-dimensional array; a plurality of base pad units supporting said foundation blocks, each base pad unit comprising a rectahedral parallelepiped one face of which is convex, the opposite face of which has a plurality of protruding lugs, and the intermediate faces of which have T-shaped slots extending the length of each side, such base pad units being interfitted into a two-dimensional array by means of I-shaped keys which fit into adjacent T-shaped slots; a plurality of leg blocks supporting said base pad units, each of said leg blocks comprising a rectangular parallelepiped one face of which is convex, the opposite face of which is concave, the opposite fac

Abstract: An electrically heated still or purifier for the distillation purification of heat transfer fluids such as diphenyl, diphenyl ether and mixtures thereof which are contaminated with high boiling thermal decomposition products. The design incorporates an internal draft tube to induce natural circulation of the boiling liquid and thereby enhance heat transfer coefficients. The purifier is especially adapted for operation with Dowtherm A at temperatures of 700.degree.-750.degree. F. for removal of thermal decomposition products and corresponding superatmospheric pressures for Dowtherm A containing low boiling contaminants or other low boiling organic fluids without danger of overheating the heat transfer fluid.

Abstract: An assembly of structural elements capable of disassembly, capable of addition horizontally and vertically, capable of reduction in size horizontally and vertically, the entire structure accomplishing such purposes and objectives by the use of precast concrete elements, precast with wire tensioning bores therethrough, so that upon assembly of such elements the assembly can be post-tensioned in place; also being subject to ready disassembly or reduction in size by removal of individual elements by facile release of the tension wires. The entire assembly thus represents a composite of basic individual structural elements, which when attached together form the basic system of the complete building unit, are capable of receiving habitable precast modules or capable also of utilization in the formation of basic floor framing systems.

Abstract: 6-Phenyl-4H-s-triazolo[4,3-a][1,4]benzodiazepines of the formula (IV): ##SPC1##wherein R is selected from the group consisting of hydrogen, alkyl of 1 to 3 carbon atoms, inclusive, phenyl, benzyl and -COOR' in which R' is alkyl of 1 to 4 carbon atoms, inclusive; wherein R.sub.1 is selected from the group consisting of hydrogen and alkyl of 1 to 3 carbon atoms, inclusive; and wherein R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are selected from the group consisting of hydrogen, alkyl of 1 to 3 carbon atoms, inclusive, halogen, nitro, cyano, trifluoromethyl, and alkoxy, alkylthio, alkylsulfinyl, alkylsulfonyl, alkanoylamino and dialkylamino in which the carbon chain moieties are of 1 to 3 carbon atoms, inclusive, are produced by condensing a 1,3-dihydro-5-phenyl-2H-1,4-benzodiazepine-2-thione of the formula (I): ##SPC2## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are defined as above, with an organic acid hydrazide of the formula: ##EQU1## wherein R is defined as above.

Abstract: A multiple effect evaporator in which the feed is progressively preheated in an indirect falling film preheater by vapors from the lower temperature effects and then further preheated by direct contact with vapors from higher temperature effects, said preheated feed being degassed during said direct contact preheating, prior to evaporation.