A silica-titania glass substrate comprising: (i) a composition comprising 5 weight percent to 10 weight percent TiO.sub.2; (ii) a coefficient of thermal expansion (CTE) at 20° C. in a range from −45 ppb/K to +20 ppb/K; (iii) a crossover temperature (Tzc) in a range from 10° C. to 50° C.; (iv) a slope of CTE at 20° C. in a range from 1.20 ppb/K.sup.2 to 1.75 ppb/K.sup.2; (v) a refractive index variation of less than 140 ppm; and (vi) 600 ppm OH group concentration or greater. The substrate can have a mass of 1 kg or greater and less than 0.05 gas inclusions per cubic inch via a method comprising (i) forming the substrate from soot particles comprising SiO.sub.2 and TiO.sub.2, and (ii) subjecting the substrate to an environment having an elevated temperature and an elevated pressure for a period of time until the substrate comprises less than 0.05 gas inclusions per cubic inch.

A silica-titania glass substrate comprising: (i) a composition comprising 5 weight percent to 10 weight percent TiO.sub.2; (ii) a coefficient of thermal expansion (CTE) at 20° C. in a range from −45 ppb/K to +20 ppb/K; (iii) a crossover temperature (Tzc) in a range from 10° C. to 50° C.; (iv) a slope of CTE at 20° C. in a range from 1.20 ppb/K.sup.2 to 1.75 ppb/K.sup.2; (v) a refractive index variation of less than 140 ppm; and (vi) 600 ppm OH group concentration or greater. The substrate can have a mass of 1 kg or greater and less than 0.05 gas inclusions per cubic inch via a method comprising (i) forming the substrate from soot particles comprising SiO.sub.2 and TiO.sub.2, and (ii) subjecting the substrate to an environment having an elevated temperature and an elevated pressure for a period of time until the substrate comprises less than 0.05 gas inclusions per cubic inch.

A method of forming a part includes forming a glass-ceramic matrix composite material to form a pre-consolidated feedstock sheet with a pre-determined shape. The pre-consolidated feedstock sheet is sectioned into a first piece of pre-consolidated feedstock sheet and a second piece of pre-consolidated feedstock sheet. The first piece of pre-consolidated feedstock sheet and a second piece of pre-consolidated feedstock sheet are assembled with a second piece of pre-consolidated feedstock sheet to form a composite layup. The first piece of pre-consolidated feedstock sheet and the second piece of pre-consolidated feedstock sheet are joined by compressing the composite layup to form a glass-ceramic matrix composite part.

A method of forming a part includes forming a glass-ceramic matrix composite material to form a pre-consolidated feedstock sheet with a pre-determined shape. The pre-consolidated feedstock sheet is sectioned into a first piece of pre-consolidated feedstock sheet and a second piece of pre-consolidated feedstock sheet. The first piece of pre-consolidated feedstock sheet and a second piece of pre-consolidated feedstock sheet are assembled with a second piece of pre-consolidated feedstock sheet to form a composite layup. The first piece of pre-consolidated feedstock sheet and the second piece of pre-consolidated feedstock sheet are joined by compressing the composite layup to form a glass-ceramic matrix composite part.

The invention discloses porous, bioactive glass and glass ceramic morsels or pellets to be used as tissue graft substitute materials and processes for obtaining the same wherein the bioactive glass and glass ceramic morsels or pellets are made up of natural agents like phosphate, calcium, sodium and other elements which are not alien to the human or animal body. The said preparation process encompasses various steps like quenching sintering, foaming, and sol-gel casting which render the glass morsels or pellets unique bioactivity and enhanced porosity which may facilitate tissue repair and augmentation during tissue graft replacement.

The invention discloses porous, bioactive glass and glass ceramic morsels or pellets to be used as tissue graft substitute materials and processes for obtaining the same wherein the bioactive glass and glass ceramic morsels or pellets are made up of natural agents like phosphate, calcium, sodium and other elements which are not alien to the human or animal body. The said preparation process encompasses various steps like quenching sintering, foaming, and sol-gel casting which render the glass morsels or pellets unique bioactivity and enhanced porosity which may facilitate tissue repair and augmentation during tissue graft replacement.

A quartz glass crucible including bottom, curved, and straight body portions, where the quartz glass crucible includes an outer layer including opaque quartz glass containing bubbles, and an inner layer including transparent quartz glass, the outer layer fabricated from different types of raw material powder, the outer layer having regions sectioned by bubble content densities, and bubble content densities of two outer layer adjacent regions, when d.sub.a (pcs/mm.sup.3) is defined as content density of a region “a” having a greater content density, and d.sub.b (pcs/mm.sup.3) is defined as content density of a region “b” having a smaller content density, a difference D=(d.sub.a−d.sub.b)/d.sub.b between content densities of the two regions is 10% or more.

A picking assembly provided by the present disclosure may include a transmission shaft; at least two rigid balls; and a support member carrying rigid balls of the at least two rigid balls. Two of the at least two rigid balls may be arranged on two opposite sides of the transmission shaft. Centers of the two of the at least two rigid balls and a center of a cross-section of the transmission shaft may be located on a same line. The transmission shaft may be movable back and forth in an axis direction of the transmission shaft.

To provide an opaque quartz glass having excellent heat insulating property, mechanical strength and surface smoothness, a silica powder water slurry of concentration of 45 to 75 wt % is subjected to wet pulverization with silicon nitride beads having a mean diameter of 0.1 mm to 3 mm. The silica powder and silicon nitride beads are subjected to abrasion and the silicon nitride powder works as foaming agent and independent spherical bubbles are formed for manufacturing opaque quartz glass which has air cells having a mean diameter of 2 to 30 m and are independent spherical, having a density of 1.90 to 2.20 g/cm.sup.3, a whiteness of 80 or more, a reflectance of 80% or more for light of a wavelength of 0.2 to 3 m at thickness of 3 mm, a bending strength of 70 MPa or more, a surface roughness Ra of the baked surface of 0.7 m or less.

To provide an opaque quartz glass having excellent heat insulating property, mechanical strength and surface smoothness, a silica powder water slurry of concentration of 45 to 75 wt % is subjected to wet pulverization with silicon nitride beads having a mean diameter of 0.1 mm to 3 mm. The silica powder and silicon nitride beads are subjected to abrasion and the silicon nitride powder works as foaming agent and independent spherical bubbles are formed for manufacturing opaque quartz glass which has air cells having a mean diameter of 2 to 30 m and are independent spherical, having a density of 1.90 to 2.20 g/cm.sup.3, a whiteness of 80 or more, a reflectance of 80% or more for light of a wavelength of 0.2 to 3 m at thickness of 3 mm, a bending strength of 70 MPa or more, a surface roughness Ra of the baked surface of 0.7 m or less.