Abstract: A high efficiency thermal interposer comprising a first hollow disk and second hollow disk, held together by thermally isolating fasteners. The fasteners keep the disks from touching one another. In an illustrative embodiment of the invention, the first disk is the low temperature disk portion and the second disk is the high temperature disk portion of the heat shield. Furthermore, according to a preferred embodiment of the invention, the space between the disks is filled with small thermally conductive particles (e.g., stainless steel spheres) which are in thermal contact with the high temperature disk; but which are not in contact with the low temperature disk. The thermal interposer/heat shield includes means for introducing cold jets of air into the cavity containing the particles, means for circulating the air therebetween, and means through which the air can exit from the cavity to carry away the heat picked up from the particles inside the cavity.

Abstract: In a bonding station the parts of the apparatus to be bonded are retained at a thermal bias temperature at a permitted level and a thermal check valve interface is provided between the bonding location and the part of the station that would serve as a conduction heat sink, thereby thermally insulating other uninvolved parts of the structure and and confining the bonding heat to the bonding region. Such confinement reduces the dwell time that the bond must remain at the bonding temperature. The bonding station has a number of features: the parts to be bonded are maintained on a support member that is provided with a heat biasing capability that can establish the assembly at a specified temperature; a retention capability, such as the use of vacuum, is provided to maintain registration and thermal contact of the part with the support; and a thermal check valve capability is provided to control the rate of heat flow through the support member so that locallized heat is controlled in dissipation.

Abstract: Reactive metals, such as titanium or nickel-chrome superalloys containing rare earths, are cast with mold and/or core surface areas formed from an improved slurry. The improved slurry contains yttria to form an inert surface which is exposed to the molten reactive metal. In order to prevent premature gelation of the slurry, the forming of defects in the mold and/or core surface areas, and the forming of defects in the cast article, the slurry contains a source of hydroxyl ions. The source of hydroxyl ions is sufficient to result in the slurry having a pH of at least 10.2 six days after initially mixing the slurry. The source of hydroxyl ions may be a metal alkali or an organic hydroxide. It is believed that the source of hydroxyl ions functions as a hydration suppressant for the yttria to prevent premature gelation of the slurry. The slurry contains a silicon oxide (SiO.sub.2) to alkali ratio which is equivalent to a silicon oxide to sodium oxide (Na.sub.

Abstract: Reactive metals, such as titanium or nickel-chrome superalloys containing rare earths, are cast with mold and/or core surface areas formed from an improved slurry. The improved slurry contains yttria to form an inert surface which is exposed to the molten reactive metal. In order to prevent premature gelation of the slurry, the forming of defects in the mold and/or core surface areas, and the forming of defects in the cast article, the slurry contains a source of hydroxyl ions. The source of hydroxyl ions is sufficient to result in the slurry having a pH of at least 10.2 six days after initially mixing the slurry. The source of hydroxyl ions may be a metal alkali or an organic hydroxide. It is believed that the source of hydroxyl ions functions as a hydration suppressant for the yttria to prevent premature gelation of the slurry. The slurry contains a silicon oxide (SiO.sub.2) to alkali ratio which is equivalent to a silicon oxide to sodium oxide (Na.sub.

Abstract: An automated tension infiltrometer including a soil contacting base to which is mounted a porous plate for interfacing the infiltrometer with the soil to be analyzed. A Marriotte column is positioned in the base so that its open bottom end abuts the porous plate. A bubble tower is also positioned in the base and has a bubbling tube operatively connected between its interior and interior of the Marriotte column. The bubble tower is adjustable to provide variable tension to the Marriotte column. First and second transducers are positioned at the upper and lower parts of the Marriotte column and continuously measure pressure changes at those positions while water from the column infiltrates into the soil. By correlating these measurements, improved precision in measuring water level is achieved, which in turn allows improved results regarding deriving soil characteristic information.

Abstract: An improved mold has a coating of material having a relatively high emissivity. The surface of the coating has an emissivity which is at least twice as great as the emissivity of the surface of the ceramic mold material. When the mold is removed from a furnace chamber, the surface of the coating radiates heat at a relatively high rate. In one embodiment of the invention, the coating is applied to only a portion of the surface of a ceramic mold. In another embodiment of the invention, the coating of material having a relatively high emissivity is applied to only a portion of a crystal selector on a mold for a single crystal article. The relatively high rate of radiation of heat from the coated portion of the crystal selector increases the rate of growth of an adjacent single crystal grain. If desired, the entire mold can be covered with the coating of material having a relatively high emissivity. The coating of material having a high emissivity may be formed of graphite.

Abstract: An apparatus for casting doubly-oriented single crystal airfoils and similar articles includes a mold having an orientation selector which selects crystals having desired vertical and horizontal orientations. The orientation selector includes an upright primary growth passage having a lower end exposed to the upper side surface of a chill plate. A horizontal secondary growth passage is connected with the upper end of the primary growth passage and with the mold cavity. A gradient inducing passage is connected with the upper end of the primary growth passage and has a lower end exposed to the chill plate to promote the transmission of heat from the upper end of the primary growth passage to the chill plate after metal crystals have solidified in the gradient inducing growth passage.

Abstract: An intermittently-operating strand delivery system having:(1) a nozzle passageway through which the strand is guided;(2) a supply for pressurized medium;(3) conduit means connecting between said nozzle passageway and said supply including a pressure-operated on-off flow valve; and(4) separate servo valve units for independently applying and releasing control pressure, respectively to and from the pressure-operated flow valve to move the cam between alternately open and closed positions to admit medium from the supply to the nozzle passageway for a controlled interval and thereby permit a pulse of medium to pass through the nozzle passageway and project a length of the weft strand therefrom. The servo units can take the form of separate solenoids or rotary spool valves. The opening of the pressure-operated valve preferably incorporates an avalanching effect to accelerate its opening action.

Abstract: A ceramic shell mold having the properties of being easily removed from the metal castings, high permeability, and a fired strength that can be controlled at levels lower than conventional molds, characterized in that the refractory used to make the mold is at least in part hydrated alumina.

Abstract: Ceramic cores suitable for use in investment casting operations are molded from a mixture containing comminuted refractory which includes partially dehydrated gypsum and a sublimable binder. When the sublimable binder has been sublimated from the molded core, it is soaked in water in order to hydrate the gypsum and cause it to set.

Abstract: A method of producing cast metal tooling, especially injection molds or dies, characterized by the steps of making a thin walled, investment cast shell which defines the functional cavity surface of the tooling, and casting a suitable backing metal against the shell to form a composite die or mold structure.

Abstract: A pattern assembly for use in the lost pattern process of investment casting characterized by a center tree or sprue member including a central stem and a plurality of laterally projecting collars spaced apart along the stem and united therewith to provide the surface area for gating the patterns, the cross-sectional size of the stem being greater than the projecting width of the collar, whereby the stem serves to form a riser.

Abstract: For use in making investment molds by the lost pattern process, a pattern material which is machinable and has the capability of being melted out of the molds without cracking them, the material consisting basically of an ethylene-vinyl resin and at least one fatty acid ketone.

Abstract: A method of making investment shell molds by the lost pattern process characterized in that a strand such as wire or the like is wound circumferentially about a pattern assembly in at least one location before it is coated with refractory material to form a mold shell. Thereafter, the strand is unwound to separate the shell into segments, each of which is usable as a mold.

Abstract: A pattern set-up especially useful for making prosthetic dental appliances is assembled by attaching a plurality of refractory casts to a support member so that adjacent casts along the length of the support member are circumferentially offset with respect to one another. The casts carry expendable patterns that are connected to the support member by gating systems laid down on faces of the casts. The support member has outward protrusions supporting the weight of the casts and may be formed by a plurality of segments fitted together in end-to-end relation.