Showing papers on "Glass microsphere published in 1979"

Centrifuge apparatus and method for producing hollow microspheres

Abstract: The hollow glass vacuum microspheres are made by forming a liquid film of molten glass across the coaxial blowing nozzles, applying the metal vapor blowing gas at a positive pressure on the inner surface of the glass film to blow the film which combines with the centrifugal force to form an elongated cylinder shaped liquid film of molten glass A transverse jet is used to direct the inert entraining fluid over and around the blowing nozzle at an angle to the axis of the blowing nozzle The entraining fluid as it passes over and around the blowing nozzle fluid dynmically induces a pulsating or fluctuating pressure field at the opposite or lee side of the blowing nozzle in the wake or shadow of the coaxial blowing nozzle The continued movement of the entraining fluid over the elongated cylinder produces asymmetric fluid drag forces on the cylinder and closes and detaches the elongated cylinder from the coaxial blowing nozzle and the detached cylinder by the action of surface tension forms into a spherical shape Quench nozzles are disposed radially away from the rotor and direct cooling fluid downwardly at and into contact with the hollow glass amicrospheres to rapidly cool and solidify the molten glass to form a hard, smooth hollow glass microsphere and where metal vapor blowing gas is used to cool and condense the metal vapor and to deposit the metal vapor on the inner wall surface of the microsphere as a thin metal coating

Method for introduction of gases into microspheres

Abstract: A method for producing small hollow glass spheres filled with a gas by introduction of the gas during formation of the hollow glass spheres. Hollow glass microspheres having a diameter up to about 500μ with both thin walls (0.5 to 4μ) and thick walls (5 to 20μ) that contain various fill gases, such as Ar, Kr, Xe, Br, DT, H2, D2, He, N2, Ne, CO2, etc. in the interior thereof, can be produced by the diffusion of the fill gas or gases into the microsphere during the formation thereof from a liquid droplet of glass-forming solution. This is accomplished by filling at least a portion of the multiple-zone drop-furnace used in producing hollow microspheres with the gas or gases of interest, and then taking advantage of the high rate of gaseous diffusion of the fill gas through the wall of the gel membrane before it transforms into a glass microsphere as it is processed in the multiple-zone furnace. Almost any gas can be introduced into the inner cavity of a glass microsphere by this method during the formation of the microsphere provided that the gas is diffused into the gel membrane or microsphere prior to its transformation into glass. The process of this invention provides a significant savings of time and related expense of filling glass microspheres with various gases. For example, the time for filling a glass microballoon with 1 atmosphere of DT is reduced from about two hours to a few seconds.

Compressed gaseous materials in a contained volume

Abstract: A method for compressing gases in a contained volume consisting of hollow glass microspheres is described. The gases are compressed under high pressure and can be easily handled and stored. The gases to be compressed and contained in the microspheres are used as blowing gases to blow the microspheres. The metal vapor deposited coating can be reflective of or transparent to visible light. The hollow glass microspheres can be made to contain a thin transparent or reflective metal coating deposited on the inner wall surface of the microspheres by adding to the blowing gas small dispersed metal particles and/or gases of organo metal compounds and decomposing the organo metal compounds. The hollow glass microspheres can be made in the form of filamented glass microspheres with a thin glass filament connecting adjacent glass microspheres.

Solar energy collector having hollow microspheres

Abstract: Hollow glass microspheres made from a low heat conductivity glass composition containing a high vacuum and a thin metal coating deposited on the inner wall surface of the microspheres are described. The hollow glass microspheres are used to make superior insulation materials in the construction of highly efficient solar energy collectors. The hollow glass microspheres can also be made to contain a thin transparent or reflective metal coating deposited on the inner wall surface of the microspheres by adding to the blowing gas small dispersed metal particles and/or gases of organo metal compounds and decomposing the organo metal compounds. The hollow glass microspheres can be made from low heat conductivity glass compositions. The microspheres can be used to make improved insulation materials and composites and insulating systems. The hollow glass microspheres can be used as filler materials in plastics, in plastic foam compositions and in concrete and asphalt compositions. The hollow glass microspheres can also be made in the form of filamented glass microspheres with a thin glass filament connecting adjacent glass microspheres.

Compression measurements of neon-seeded glass microballoons irradiated by CO/sub 2/-laser light

Abstract: Compression of DT-neon-seeded, glass microballoons has been observed in CO/sub 2/-laser experiments at Los Alamos Scientific Laboratory. DT densities of the order of 20% of liquid density have been attained. Detailed comparisons of the neon densities determined from the measured neon source size and from the fit of observed spectra by Stark-broadening calculations have been made. The excellent agreement obtained with these methods indicates that the extrapolation of the microfield effects used in Stark-broadening calculations to high densities is reasonable.

Sputter coating of microspherical substrates by levitation

Abstract: Microspheres are substantially uniformly coated with metals or nonmetals by simultaneously levitating them and sputter coating them at total chamber pressures less than 1 torr. A collimated hole structure 12 comprising a parallel array of upwardly projecting individual gas outlets 16 is machined out to form a dimple 11. Glass microballoons, which are particularly useful in laser fusion applications, can be substantially uniformly coated using the coating method and apparatus.

A new technique for fabricating cryogenic laser‐fusion targets using cold‐gas jets

Abstract: A new technique of fabricating a uniform layer of solid DT inside a glass microshell has been developed using a heater‐wire–cold‐gas‐jets combination. A D2‐filled glass microsphere was continuously cooled by two cold‐helium‐gas jets, and a controlled amount of current was pulsed through a heater wire surrounding the microshell. This gave rise to fast evaporation and refreezing of the D2 inside the glass shell, resulting in a uniform layer of frozen D2. This new scheme has potential application in the development of a target‐fabrication system which would allow for continuous fabrication, inspection, and delivery of cryogenic laser‐fusion targets.

Composite epoxy glass-microsphere-dielectrics for electronic coaxial structures

Abstract: A composite epoxy/glass-microsphere-dielectric for hermetic R.F. connectors and coaxial cables is provided. A material which is a composition of moisture resistant epoxy resin, curing agent, glass microspheres, and silane coupling agent provide a low dielectric constant material to be molded into the various geometrics required for hermetic R.F. connectors and coaxial cables.

Fuel content characterization and pressure retention measurements of DT‐filled laser fusion microballoon targets

Abstract: We have developed a nondestructive assay of the fule content of deuterium‐tritium (DT) ‐filled microballoon laser fusion targets, which is based on β‐particle counting rates. Using a model employing transmission measurements of kilovolt electrons through thin films, observed count rates are correlated with the amount of tritium in the glass walls and hollow interior of the microballoons. It has been shown that gas pressure in balloons can be calculated from tritium content and a knowledge of the initial gas composition since D and T were found to leak at the same rate. This assay technique is primarily applicable for balloons with glass wall thicknesses <1.5 μm where the number of escaping β particles is large compared with the number of x‐ray photons generated in the glass. The technique has been applied to measure the pressure retention characteristics of individual targets. At room temperature, the balloons exhibited widely diverse and rapid leakage rates which could not be correlated with a model based on molecular diffusion and the assumption that all balloons had a homogeneous composition. Cryogenic storage greatly reduced the leakage rates with pressure retention half‐lives ranging from 5 to approximately 12 years. Finally, it was determined that tritium in the glass wall is trapped and evidence is presented to support the hypothesis that it is uniformly distributed across the shell.

X-ray measurement of laser fusion targets using least squares fitting.

Abstract: This paper presents an x-ray technique for measurement of opaque hollow microspheres used as laser fusion targets. We describe a nondestructive method for holding microspheres that enables microsphere rotation between x-ray exposures. We record film images of the microspheres using contact microradiography. We use computer image analysis for measurement of the microsphere characteristics, which involves mathematically modeling processes that relate the microsphere characteristics to film density and then applying a least squares fit of the model to the image data. We compared this measurement with the optical interferometric measurement for several glass microspheres and found measurement differences <0.3 μm for wall thickness and 0.1 μm for nonconcentricity.

Process for making hollow carbon microspheres

Abstract: A process and apparatus for making hollow carbon microspheres starting with hollow microballoons made of a material which can by heating be degraded to a carbon structure having a shape similar to that of the original microballoon The disclosure teaches specific batch treating steps and apparatus for optimizing the rate of production of the microspheres, while at the same time minimizing degradation, rupture and cracking of the resulting carbon product

Fabrication of glass spheres for laser fusion targets

Abstract: We have developed processes for mass producing the quality glass microspheres required for current laser fusion experiments. We describe the advances in the methods and materials used in our liquid droplet and dried gel systems.

Hollow microspheres and applications thereof

Abstract: Hollow glass microspheres (62) made from a low heat conductivity glass composition containing a high vacuum and a thin metal coating (63) deposited on the inner wall surface of the microspheres are described. The hollow glass microspheres are used to make superior insulation materials in the construction of highly efficient solar energy collectors. The hollow glass microspheres can also be made to contain a thin transparent or reflective metal coating deposited on the inner wall surface of the microspheres by adding to the blowing gas small dispersed metal particles and/or gases of organo-metal compounds and decomposing the organo-metal compounds. The hollow glass microspheres can be made from low heat conductivity glass compositions. The microspheres can be used to make improved insulation materials and composites and insulating systems, and panels (61). The hollow glass microspheres can be used as filler materials in plastics, in plastic foam compositions and in concrete and asphalt compositions. The hollow glass microspheres can also be made in the form of filamented glass microspheres with a thin glass filament connecting adjacent glass microsphere.

Epoxy resin composition for synthetic wood

Abstract: PURPOSE:To obtain a cured article having well-balanced lightweight and cutting properties, surface and mechanical strengths, by hot-curing a blend of an epoxy resin, specific amounts of glass microballoons, and silas balloons, and a curing agent CONSTITUTION:An epoxy resin having one or more epoxy groups in the molecule is incorporated with (A) glass microballoons having a specific gravity of 02-04 and a particle size <=200mu comprising borosilicate or silica glass and (B) 10-50% by wt based on (A) of silas balloons having a specific gravity of 01-04 and a particle size <=600mu to give the total content of (A) and (B) of 30-60% based on the whole composition The composition is then kneaded with a polyamine or acid anhydride type curing agent, eg triethylene tetramine, filled in a mold of given shape, and hot-cured The resulting article is suitable for synthetic wood, particularly a master model, and reusable because of high scratch resistance

The upgrading of glass microballoons

Abstract: The processes and mechanisms involved in producing glass microballoons of acceptable quality for laser fusion by gas jet levitation and manipulation were studied. Glass microballoons (GMBs) levitated at temperatures below, as well as above the liquidus, appear to diffuse sulfur dioxide, a polar molecule with a moderately large diameter, and hydrogen, a much smaller molecule at comparable rates. Rates on the order of tens of atmospheres per hour (constant volume) per atmosphere of partial pressure differential have been observed at temperatures around the liquidus. Relatively rapid and convenient filling of molten GMBs by levitation in deuterium and tritium appears to be a possibility.

Process for manufacturing porous glass and porous glass obtained by such process

Abstract: The known technique for manufacturing porous glass with closed pores, wherein the glass foam is rapidly cooled and nearly frozen, gives a relatively thin pore glass. Nevertheless, in order to improve the thermal insulation characteristics of the porous glass, which are essential when it is used as construction and insulating material, a relatively coarse porous structure is desired. To obtain such a structure, the glass foam is submitted to inflation until most part of the lamillar walls situated between the different bubbles of the foam are tom and a plurality of neighbouring bubbles merge into a single cavity. During inflation, the influence of heat on the glass foam is maintained after its formation and/or the ratio between the average gas pressure in the foam bubbles and the pressure acting from outside on the foam is raised to a value higher than the value of this ratio obtained with the formation of the foam and/or the surface tension of the glass forming the lamellar walls, opposing to the gas being in the bubbles of the foam as well as the resistance to the glass pressure are brought down to values lower than those obtained with the formation of the foam.