Abstract: Compound preforms are provided having a first region, including a porous ceramic and a second region including a porous or solid ceramic in which the two regions differ in composition. The compound preform is infiltrated with a liquid metal which is then solidified to form a metal matrix composite.

Abstract: Compound preforms are provided having a first region, including a porous ceramic and a second region including a porous or solid ceramic in which the two regions differ in composition. The compound preform is infiltrated with a liquid metal which is then solidified to form a metal matrix composite.

Abstract: Compound preforms are provided having a first region, including a porous ceramic and a second region including a porous or solid ceramic in which the two regions differ in composition. The compound preform is infiltrated with a liquid metal which is then solidified to form a metal matrix composite.

Abstract: A cutting tool of the type having a tool support with a cutting tip of CVD diamond film brazed to it has the diamond material so oriented that the general direction of grain boundaries is not normal to the general plane of the rake face.

Abstract: A process for providing a seal around a reciprocating and/or rotating shaft as in an apparatus for manipulating a fluid at least in part by the rotary and/or reciprocal motion of the shaft, involving the insertion of substantially identically configured free-floating seal elements into the gap between the shaft and its housing, and the improved apparatus resulting therefrom.

Abstract: Strong and durable silicon nitride filtration membranes with effective separating layers having effective pore diameters less than about 1 micron are produced by depositing a source of silicon onto a porous microfilter support, removing any liquid used in the depositing, and subjecting the silicon source to nitridation conditions. Suitable sources of silicon include silicon per se and silica. When silica is used, a suitable reducing agent is deposited therewith to reduce the silica to silicon in situ.

Abstract: Strong and durable alpha alumina ultrafiltration membranes with effective separating layers having effective pore diameters less than about 50 nm, and particularly at almost any point within the range of about 10 to about 50 nm, can be produced by seeding boehmite sols with appropriate seeds, such as very fine alpha alumina with a specific surface area of more than 100 sq. m. per g, gelling a thin layer of the sol by contact with a microfilter support, drying the gel, followed by controlled heating of the coated support both to convert the boehmite to alpha alumina and to simultaneously control the effective pore diameter of the resultant membrane.

Abstract: This invention is a method and an apparatus for rapidly devolatilizing a product of a polymerization process containing at least one volatile material. The product is initially devolatilized in a high temperature zone, and the foamed devolatilized product is separated into a gas and a liquid polymer phase and rapidly removed therefrom to minimize depolymerization and degradation of the polymer. The partially devolatilized product is further devolatilized by feeding it into a rotatable chamber which is rotated at a sufficient angular velocity to create a high gravitational field to form a vapor and a polymer liquid pool.

Abstract: A devolatilization apparatus is provided which removes volatiles from a variety of polymer products utilizing centrifugal forces to control the residence time of the polymer in the devolatilizer. Volatiles are efficiently removed without degrading the polymer product. The devolatilizer includes a rotatable annular chamber having an inlet, a first outlet located at a first distance from the axis of rotation of the chamber, and a second outlet located at a second distance from the axis of rotation of the chamber. Means are also provided for supplying a polymer, in liquid form, to the inlet to the annular chamber. The portion of the chamber located between the first and second outlets forms an annular pocket or subchamber. The apparatus also includes means to rotate the annular chamber at a speed sufficient to cause the liquid polymer to flow through the first and second outlets and form liquid seals at each of the outlets.

Abstract: The invention is an apparatus that allows a motor to move in any one of three linear directions, but it restrains rotary motion of the motor housing. In practice, the motor is used for driving a pump or some other rotary motion device. The device includes a lever arm fastened to the motor housing and a hydraulic cylinder pivotally connected to each end of the arm and to a support member. Each cylinder is divided into two chambers by a piston head, and hydraulic lines connect the chambers of one cylinder to the chambers of the other cylinder. When the pump (or other rotary motion device) tends to cause rotational movement of the motor housing, and lever arm, each cylinder responds to this rotational load by trying to displace fluid (oil) from one cylinder to the other. Since each cylinder tries to displace an equivalent volume of oil toward the other cylinder, through a common conduit, displacement of the oil is not possible.

Abstract: This invention provides thin, flat, water-impervious polycrystalline ceramic bodies composed of at least 99.5% by weight alumina, predominantly in the alpha crystal form. These bodies have a density of at least 3.9 Mg/m.sup.3, an average surface roughness of 44 nm or less, typically 40 nm or less. The properties of the finished ceramic bodies make them ideal substrates for highly reliable electronic components, especially for high temperature environments. Processes for obtaining such bodies by direct firing of slip cast tapes are also described.

Abstract: A waste disposal mixer is shown suitable for the encapsulation of radioactive wastes in synthetic resins. The mixer permits the selective discarding of the agitator member and of a drip pan selectively positionable to receive dripping material from the agitator. The agitator can be selectively replaced, all movements being controlled remotely.

Abstract: An improved heat transfer or chill roll is disclosed employing a static mandrel, and agitation within the roll together with longitudinal distribution of the heat exchange fluid provides increased uniformity of surface temperature.

Abstract: Improved shaft seal is provided wherein generally radially extending distendable diaphragms are used to adjust the sealed gap. A flushing lubricant is provided. The seal is particularly suited for use in gear pumps handling viscous materials such as heat plastified thermoplastics.

Abstract: Rigid plastic foam is flexibilized in an apparatus utilizing four sets of foam gripping belts. A first and second set of opposed belts traveling at a given speed forward the foam into the apparatus to a second and third set of opposed belts traveling at a slower speed than the first and second set of belts. The first and third and the second and fourth sets of belts are interdigitated in a region of foam crush.

Abstract: A tube perforator is provided which has a generally cylindrical mandrel which extends within a tube. The mandrel is hollow and has a passage therein which extends in angular relation to the axis of the mandrel and exits on one side thereof. A punch disposed in the passage can be driven against the tube wall to cause perforation thereof.

Abstract: A heat exchange assembly is provided which employs concentric flat plate heaters, the heat exchange assembly having a common fixed tube sheet and floating tube sheet; the floating tube sheet comprising two concentric portions having frustoconical interface thereby, the frustoconical interface when projected has its apex in a plane containing the adjacent face of the fixed tube sheet in the axis of generation of the flat plate heater. Thermal stress on the floating tube sheet is thereby relieved. The heat exchanger is useful as a reactor particularly where the temperature profile of the material flowing therethrough is controlled or varied.

Abstract: Profiled heat seals in plastic film are provided by opposed profiled heat sealing platens supported on endless chains. The platens are heated by contact with associated heating drums.

Abstract: Laminated heating elements are provided which are suitable for joining synthetic resinous thermoplastic bodies particularly thermoplastic foams. The heating elements are of laminar structure having at least two oppositely disposed heating elements which electrically may be fed in parallel. A significant improvement in rigidity and resistance to mechanical abuse is achieved.

Abstract: Thermoplastic foam bodies are readily generally continuously laminated together wherein the joint therebetween contains a reinforcing scrim. Friction on each of the foam bodies is generally equalized by positioning the scrim relative to both major faces of the heating element employed for the lamination to obtain a desired degree of curvature in the laminate.