Abstract: Hollow shells of high uniformity are formed by emitting liquid through an outer nozzle and gas through an inner nozzle, to form a hollow extrusion, by flowing the gas at a velocity between about 1.3 and 10 times the liquid velocity. The natural breakup rate of the extrusion can be increased to decrease shell size by applying periodic perturbations to one of the materials prior to exiting the nozzles, to a nozzle, or to the extrusion.

Abstract: Systems are described for using multiple closely-packed spheres. In one system for passing fluid, a multiplicity of spheres lie within a container, with all of the spheres having the same outside diameter and with the spheres being closely nested in one another to create multiple interstitial passages of a known size and configuration and smooth walls. The container has an inlet and outlet for passing fluid through the interstitial passages formed between the nested spheres. The small interstitial passages can be used to filter out material, especially biological material such as cells in a fluid, where the cells can be easily destroyed if passed across sharp edges. The outer surface of the spheres can contain a material that absorbs a constitutent in the flowing fluid, such as a particular contamination gas, or can contain a catalyst to chemically react the fluid passing therethrough, the use of multiple small spheres assuring a large area of contact of these surfaces of the spheres with the fluid.

Abstract: Laser pyrometer techniques are utilized to accurately image a true temperature distribution on a given target without touching the target and without knowing the localized emissivity of the target. The pyrometer utilizes a very high definition laser beam and photodetector, both having a very narrow focus. The pyrometer is mounted in a mechanism designed to permit the pyrometer to be aimed and focused at precise localized points on the target surface. The pyrometer is swept over the surface area to be imaged, temperature measurements being taken at each point of focus.

Abstract: The improved, heterogeneous catalysts are in the form of gas-impervious, hollow, thin-walled spheres (10) suitably formed of a shell (12) of metal such as aluminum having a cavity (14) containing a gas at a pressure greater than atmospheric pressure. The wall material may be, itself, catalytic or the catalyst can be coated onto the sphere as a layer (16), suitably platinum or iron, which may be further coated with a layer (18) of activator or promoter. The density of the spheres (30) can be uniformly controlled to a preselected value within .+-.10 percent of the density of the fluid reactant such that the spheres either remain suspended or slowly fall or rise through the liquid reactant.

Abstract: Improved, heterogeneous, refractory catalysts are in the form of gas-impervious, hollow, thin-walled spheres (10) suitable formed of a shell (12) of refractory such as alumina having a cavity (14) containing a gas at a pressure greater than atmospheric pressure. The wall material may be itself catalytic or a catalytically active material coated onto the sphere as a layer (16), suitably platinum or iron, which may be further coated with a layer (18) of activator or promoter. The density of the spheres (30) can be uniformly controlled to a preselected value within .+-.10 percent of the density of the fluid reactant such that the spheres either remain suspended or slowly fall or rise through the liquid reactant.

Abstract: Improved, heterogeneous, refractory catalysts are in the form of gas-impervious, hollow, thin-walled spheres (10) suitable formed of a shell (12) of refractory such as alumina having a cavity (14) containing a gas at a pressure greater than atmospheric pressure. The wall material may be itself catalytic or a catalytically active material coated onto the sphere as a layer (16), suitably platinum or iron, which may be further coated with a layer (18) of activator or promoter. The density of the spheres (30) can be uniformly controlled to a preselected value within .+-.10 percent of the density of the fluid reactant such that the spheres either remain suspended or slowly fall or rise through the liquid reactant.

Abstract: An apparatus is provided for forming gas-filled spheres of metal, glass or other material, which produces spheres (12) of uniform size and wall thickness in a relatively simple system. The system includes concentric nozzles, including an inner nozzle (18) through which gas flows and and an outer nozzle (20), which jointly define an annular passageway (50) through which a liquid flows. The flow rates are adjusted so that the gas flows at greater velocity than does the liquid, out of their respective nozzles, e.g. three times as great, in order to produce an extrusion (30) which undergoes axisymmetric oscillations resulting in the pinch off into hollow spheres with very uniform spacing. The system is useful not only where gas-filled spheres are required, but also is useful to accurately control the dispensing of solid, liquid, or gaseous materials.

Abstract: The improved, heterogeneous catalysts are in the form of gas-impervious, hollow, thin-walled spheres (10) suitably formed of a shell (12) of metal such as aluminum having a cavity (14) containing a gas at a pressure greater than atmospheric pressure. The wall material may be, itself, catalytic or the catalyst can be coated onto the sphere as a layer (16), suitably platinum or iron, which may be further coated with a layer (18) of activator or promoter. The density of the spheres (30) can be uniformly controlled to a preselected value within .+-.10 percent of the density of the fluid reactant such that the spheres either remain suspended or slowly fall or rise through the liquid reactant.

Abstract: An electrostatic levitation system is described, which can closely control the position of objects of appreciable size. A plurality of electrodes surround the desired position of an electrostatically charged object, the position of the object is monitored, and the voltages applied to the electrodes are varied to hold the object at a desired position. In one system, the object is suspended above a plate-like electrode (16, FIG. 1) which has a concave upper face (26) to urge the object toward the vertical axis (20) of the curved plate. An upper electrode (18) that is also curved can be positioned above the object, to assure curvature of the field at any height above the lower plate. In another system, four spherical electrodes (81-84, FIG. 6) are positioned at the points of a tetrahedron, and the voltages applied to the electrodes are varied in accordance with the object position as detected by two sensors (94,96 FIG. 4).

Abstract: An apparatus is described for producing a lightweight structural material (12), by forming gas-filled shells (38) of molten material from a matrix of nozzles (22) that form shells of very uniform size at very uniform rates. The matrix of molten shells coalesce into a multi-cell material of controlled cellular structure. The shells can be of two different sizes (38, 44) that are interspersed, to form a multicell material that has a regular cell pattern but which avoids planes of weakness and localized voids. The gas (50) in the shells can be under a high pressure, and can be a fire extinguishing gas.

Abstract: A system is described for acoustically controlled rotation of a levitated object (12), which avoids deformation of a levitated liquid object. Acoustic waves (50, 52 in FIG. 6) of the same wavelength are directed along perpendicular directions across the object, and with the relative phases of the acoustic waves repeatedly switched so that one wave alternately leads and lags the other by 90.degree.. The amount of torque for rotating the object, and the direction of rotation, are controlled by controlling the proportion of time one wave leads the other and selecting which wave leads the other most of the time.

Abstract: A method is described for removing bubbles (14) from a liquid bath (12), such as a bath of molten glass to be used for optical elements. Larger bubbles are first removed by applying acoustic energy resonant to a bath dimension (H) to drive the larger bubbles toward a pressure well (30) where the bubbles can coalesce and then be more easily removed. Thereafter, submillimeter bubbles (50) are removed by applying acoustic energy of frequencies resonant to the small bubbles to oscillate them and thereby stir liquid immediately about the bubbles to facilitate their breakup and absorption into the liquid (16).

Abstract: A system is described for acoustically moving an object within a chamber, by applying wavelengths of different modes to the chamber to move the object between pressure wells formed by the modes. In one system, the object (96, FIG. 7) is placed in a first end portion of the chamber while a resonant mode is applied along the length of the chamber that produces a pressure well (86) at that location. The frequency is then switched to a second mode that produces a pressure well (100) at the center of the chamber, to draw the object thereto. When the object reaches the second pressure well and is still travelling towards the second end of the chamber, the acoustic frequency is again shifted to a third mode (which may equal the first mode) that has a pressure well (106) in the second end portion of the chamber, to draw the object thereto.

Abstract: A system is described for forming hollow spheres containing pressured gas, which includes a cylinder device (14) containing a molten solid material (20) and having a first nozzle (18) at its end, and a second gas nozzle (24) lying slightly upstream from the tip of the first nozzle and connected to a source (26) that applies pressured filler gas that is to fill the hollow spheres. High pressure is applied to the molten metal, as by moving a piston (22) within the cylinder device, to force the molten material out of the first nozzle and the same time pressured gas fills the center of the extruded hollow liquid pipe that breaks into hollow spheres (12a). The environment (54) outside the nozzles contains gas at a high pressure such as 100 atmospheres, the gas is supplied to the gas nozzle (24) at a slightly higher pressure such as 101 atmospheres, and the pressure applied to the molten material (20) is at a still higher pressure such as 110 atmospheres.

Abstract: Hollow spheres with precisely concentric inner and outer spherical surfaces are formed by applying vibrations to a nonconcentric hollow sphere while it is at an elevated temperature at which it is fluid or plastic, the vibrations producing internal flows which cause the inner and outer surfaces to become precisely concentric. Concentric spheres can be mass produced by extruding a material such as glass or metal while injecting a stream of gas into the center of the extrusion to form a gas-filled tube. Vibrations are applied to the extruded tube to help break it up into individual bodies of a desired uniform size, the bodies tending to form spherical inner and outer surfaces by reason of surface tension, and the continuing application of vibrations causing these surfaces to become concentric.

Abstract: A suspended mass is shaped by melting all or a selected portion of the mass and applying acoustic energy in varying amounts to different portions of the mass. In one technique for forming an optical waveguide slug, a mass of oval section is suspended and only a portion along the middle of the cross-section is heated to a largely fluid consistency. Acoustic energy is applied to opposite edges of the oval mass to press the unheated opposite edge portions together so as to form bulges at the middle of the mass. In another technique for forming a ribbon of silicon for constructing solar cells, a cylindrical thread of silicon is drawn from a molten mass of silicon, and acoustic energy is applied to opposite sides of the molten thread to flatten it into a ribbon.