Abstract: A method of passivating a Group III-V compound surface by exposing the surface to a compound A-B, wherein A is an element having a heat of oxide formation greater than the heats of oxide formation of Group III and V elements and B is an element: S, Se, Te or Po.

Abstract: A method of determining the proportion of the surface area of a coated substrate that is covered by the coating comprising passing a known volume of an adsorbate gas under controlled flow conditions over a coated substrate and measuring the volume of adsorbate gas adsorbed on the surface area at different temperatures between the liquefaction temperature of the adsorbate gas and ambient temperature; similarly measuring the volume of the adsorbate gas adsorbed on the surface area of the substrate in the absence of the coating in the same temperature range; similarly measuring the volume of the adsorbate gas adsorbed on said coating in the absence of said substrate in the same temperature range; comparing the above volumes at identical temperatures and calculating therefrom the proportion of surface area of said substrate covered by said coating; and an apparatus for practicing said method.

Abstract: A particular papermachine and type of pulp stock for forming a particular basis weight web are analyzed for deriving a correlation between pulp stock drainage rate and the lowest obtainable critical moisture content of said paper web. From knowledge of the lowest critical moisture content and main steam pressure, differential pressure values between the several dryer pressure sections of the papermachine are determined for drying said web along the most energy-efficient drying rate trajectory. Also disclosed is a dryer steam pressure differential control program for maintenance of a pre-determined magnitude of condensate inventory within the drying cylinders under normal running conditions and under conditions of interrupted web continuity.

Abstract: Soap is separated from spent, cellulosic pulping liquor by strenuously percolating a gaseous, aliphatic hydrocarbon through a quantity of liquor volume under such temperature and pressure conditions that an equilibrious strata of liquid phase hydrocarbon is sustained on the surface of the liquor. Following strenuous combination and agitation, the gas-liquor mixture is allowed to settle so that the entrained, gaseous hydrocarbon and coagulated soap floc gravimetrically rises to the liquor surface and stratifies with the soap layer between the residual liquor solution and a liquid phase layer of hydrocarbon. Thereafter, the liquid hydrocarbon and soap layer are decanted away from the residual liquor solution and depressurized to vaporize the hydrocarbon leaving a reservoir of isolated soap.

Abstract: Pulping liquor borne solids are concentrated within an aqueous solution by a successive plurality of freezing steps wherein a discrete quantity of the solution is crystallized in each step by freezing. The water crystals from each freezing step are subsequently separated from the remaining liquid solution by screening and applying axial pressure to the crystalline mass. Greater efficiencies may be obtained in some cases by mixing or reslurrying a pressed, crystalline mass and pressing a second time. Another auxiliary separation step comprises a quiescent thaw of the crystalline mass from the first two press steps to permit additional dissolved solids to be drained away from the purified water ice.