Showing papers on "Glass microsphere published in 1976"

Permeation of helium and hydrogen from glass‐microsphere laser targets

Abstract: Isothermal outgassing curves of hollow glass microspheres filled with helium, hydrogen, or deuterium gas have been determined. Four million 40–45‐μm soda‐lime glass microspheres, similar to laser‐fusion targets, were filled by gas permeation at 693–763 K and outgassed at 292–573 K. The permeabilities were calculated by an exponential theory, and they agree to an order of magnitude with the literature values. The outgassing curves are not pressure dependent. Two irregularities are apparent. First, the counting of target‐quality individual D‐T–filled microspheres shows a permeability spread of an order of magnitude from one microsphere to the next, which may be caused by variable chemical composition. Second, all the gases show deviations from exponential behavior in the form of tails at long times. Chemical reaction of the hydrogen with the glass, as well as incomplete filling and outgassing, may cause the hydrogen tails; the cause of the helium tails is not known.

Low density ablator compositions

Abstract: Two types of highly filled, elastomeric silicone-base abiative compositions whose densities range from about 0.20 g/cc to about 0.30 g/cc. One type is a carbon char forming, high thermal efficiency ablator containing at least 92 percent by volume of low density filler with a total filler-to-resin volumetric ratio of at least 16 to 1. The additives comprise ground cork, silica or glass microspheres, phenolic microballons and silica and/or carbon fibers. The second type is a silica char forming, RF-transparent ablator containing at least 90 percent by volume of low density filler with a total filler-to-resin volumetric ratio of at least 11 to 1. The additives comprise silica or glass microspheres and silica fibers.

Ash coated cellular glass pellet

Abstract: A foam glass pellet comprising a core of cellular glass and a coating of fine ash particles substantially enclosing said cellular glass core and bonded thereto is disclosed. The foam glass pellet is derived from a glass having a softening point less than 1250° C. The pellets have a median size of about 0.5 to about 20 millimeters and a bulk density of about 8 lbs/ft. 3 to about 50 lbs./ft. 3 pounds per cubic feet or higher if desired. The ash coating is substantially a mono particle thick layer of ash bonded to the foam glass core. Fly ash is a particularly effective ash for this purpose. Also disclosed are foam glass pellets wherein the core of cellular glass comprises a glass foam body having ash particles dispersed therein. The foam glass pellets of this invention have superior strength and are particularly useful as a light-weight aggregate in matrices such as concrete, thermosetting and thermoplastic organic polymer bodies, metals and gypsum and plaster materials.

Composite for improved stripline board material

Abstract: A stripline board material of hollow glass microspheres chemically bonded to a coating material and physically held in a polymeric matrix, preferably homo- or co-polymers of ethylene, propylene and/or styrene. The coating material is a difunctional silane with one functional group bound to the glass and the other bound either to the matrix or to a copolymer of a structure similar to the structure of the matrix. In the latter case, the sphere-silane-copolymer forms an intimate mixture with the matrix.

Polybutadiene compositions containing reinforcing glass microspheres and carbon fibers

Abstract: An improved low density resin composition results from curing, in the presence of at least one free radical generator, a resin comprising: A. polybutadiene containing 50-80% of 1,2 units and having an average moleuclar weight by number lower than 100,000; and B. inorganic or organic hollow spheres included therein. The resin composition preferably contain a fibrous reinforcing filler, preferably short carbon fibers.

Implosion experiments with an asymmetrically irradiated laser fusion target

Abstract: A spherical glass microsphere filled with DT gas and mounted on a glass plate was imploded with a single neodymium glass laser beam. Volume compression ratios of 50-100 fold and 104 14 MeV neutrons were observed.

Characteristics of hollow glass microspheres as an insulating material and an opacifier

Abstract: Thermal conductivity measurements were performed to determine the characteristics of hollow glass microspheres as an insulating material and as an opacifying agent for other insulations. The experiments were carried out with a radial flow heat transfer apparatus especially designed to suppress extraneous heat transfers, both internal and external to the heated section, and to provide uniform temperatures on the bounding surfaces. Three types of microsphere insulations were investigated, differing in bulk density and in the presence or absence of an aluminizing coating. The thermal conductivity of the microsphere insulations was found to be about one and a half times that of stagnant air over a wide temperature range. Additional experiments, involving the use of an opacifier (powdered silicon), demonstrated that radiative transfer has a minor effect on the thermal conductivity of microsphere insulations. This finding was corroborated by the fact that the high-temperature conductivity of the aluminized microspheres was not appreciably different from that of the uncoated microspheres. Another set of experiments was performed in which microsphere insulation was added to opacify silica aerogel, a fine powder insulation that is markedly affected by radiative transfer. The presence of the microspheres brought about reductions in conductivity of almost a factor ofmore » two at an optimum mixture ratio of the constituents. Furthermore, it was found that the conductivity of such a mixture was lower than that of either constituent, thereby illustrating their synergistic interaction.« less

Method for stiffening shoe uppers

Abstract: Stiffening method in which the strength, stiffness and application properties of thermoplastic synthetic polymer resin stiffening material are improved through combination with the resin of controlled proportions of glass microspheres and the composition is applied as a layer in molten condition on the portion of a shoe upper to be stiffened and is hardened by cooling.

Fast‐triton detector for laser fusion

Abstract: A triton time‐of‐flight detector consisted of a CD2 foil in front of a shielded scintillator‐photomultiplier. In neutron‐generating laser‐fusion experiments with DT gas inside glass microspheres, no substantial number of tritons occurred in the velocity range corresponding to the observed ’’fast’’ (glass) ions. Streaming can be excluded as the primary mechanism for neutron production.

Characteristics of hollow glass microspheres as an insulating material and an opacifier.

Abstract: Thermal conductivity measurements were performed to determine the characteristics of hollow glass microspheres as an insulating material and as an opacifying agent for other insulations. The experiments were carried out with a radial flow heat transfer apparatus especially designed to suppress extraneous heat transfers, both internal and external to the heated section, and to provide uniform temperatures on the bounding surfaces. Three types of microsphere insulations were investigated, differing in bulk density and in the presence or absence of an aluminizing coating. The thermal conductivity of the microsphere insulations was found to be about one and a half times that of stagnant air over a wide temperature range. Additional experiments, involving the use of an opacifier (powdered silicon), demonstrated that radiative transfer has a minor effect on the thermal conductivity of microsphere insulations. This finding was corroborated by the fact that the high-temperature conductivity of the aluminized microspheres was not appreciably different from that of the uncoated microspheres. Another set of experiments was performed in which microsphere insulation was added to opacify silica aerogel, a fine powder insulation that is markedly affected by radiative transfer. The presence of the microspheres brought about reductions in conductivity of almost a factor ofmore » two at an optimum mixture ratio of the constituents. Furthermore, it was found that the conductivity of such a mixture was lower than that of either constituent, thereby illustrating their synergistic interaction.« less