One aspect relates to a process for the preparation of a quartz glass body. The process includes providing a silicon dioxide granulate from a pyrogenically produced silicon dioxide powder, making a glass melt out of silicon dioxide granulate, and making a quartz glass body out of at least part of the glass melt. The size of the quartz glass body is reduced to obtain a quartz glass grain. The quartz glass body is processed to make a preform and an opaque quartz glass body is made from the preform. One aspect further relates to an opaque quartz glass body which is obtainable by this process. One aspect further relates to a reactor and an arrangement, which are each obtainable by further processing of the opaque quartz glass body.

The invention relates to a process for the preparation of a quartz glass body comprising the process steps i.) Providing silicon dioxide particles, ii.) Making a glass melt out of the silicon dioxide particles in an oven and iii.) Making a quartz glass body out of at least part of the glass melt, wherein the oven has a gas outlet through which gas is removed from the oven, wherein the dew point of the gas on exiting the oven through the gas outlet is less than 0 C. The invention further relates to a quartz glass body which is obtainable by this process. The invention further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

Glasses that can be chemically strengthened and are colored by transition metals. Most of the glasses are black, with some having high damage resistance and compressive surface layers having high compressive stress and depth of layer after ion exchange. These colored glasses do not require a post-forming heat treatment to produce color and are formable by fusions drawing, rolling, slot drawing, and float glass processes.

An item of equipment includes at least one worktop formed of at least one substrate made of monolithic glass material with a surface area of greater than 0.7 m.sup.2. The substrate exhibits a luminosity L* of greater than 10, a light transmission T.sub.L of less than 50%, and an opacity indicator of greater than 90. The item of equipment also includes at least one heating element and at least one interface for communication with at least one element of the worktop, such as the heating element(s), and/or with at least one external element for wireless communication. The item of equipment is devoid of light source(s).

An integrated dental porcelain system for making dental prostheses and restorations is provided. The system includes three universal major components: a) opaque porcelain composition; b) pressable dentin ingot; and c) veneering porcelain composition that can be used interchangeably for making restorations. Techniques for making the prostheses and restorations include porcelain fused-to-metal (PFM), press-to-metal (PTM), and either pressed and/or machined all-ceramic methods. The system uses both a hand-layering of veneering porcelain (PFM technique) and a hot-pressing process (PTM and all-ceramic technique) to fabricate the prostheses and restorations.

Aspects of this disclosure pertain to a colorless material that includes a carrier, copper-containing particles, and quaternary ammonium. In one or more embodiments, the material exhibits, in the CIE L*a*b* system, an L* value in the range from about 91 to about 100, and a C* value of less than about 7, wherein C* equals (a*.sup.2+b*.sup.2). In some embodiments, the material exhibits a greater than 3 log reduction in a concentration of Staphylococcus aureus, under the EPA Test Method for Efficacy of Copper Alloy as a Sanitizer testing conditions.

One aspect relates to a process for the preparation of a quartz glass grain, including providing a silicon dioxide granulate from a pyrogenically produced silicon dioxide powder, making a glass melt out of silicon dioxide granulate, making a quartz glass body out of at least part of the glass melt and reducing the size of the quartz glass body to obtain the quartz glass grain. One aspect further relates to a quartz glass grain which is obtainable by this process. One aspect further relates to opaque quartz glass bodies, which are obtainable by further processing of the quartz glass grain.

A method for producing a curved laminated glazing, for a windscreen or roof of a motor vehicle includes providing a first glass sheet, coated on at least one part of one of its faces with a stack of thin layers, depositing, on one part of the surface of the stack of thin layers in a zone to be cleared, a washable dissolving layer, a pre-firing after which the stack of thin layers located under the washable dissolving layer is dissolved by the washable dissolving layer, creating a cleared zone, the removal of the washable dissolving layer by washing, the deposit, at least on one part of the cleared zone, of an opaque mineral layer, the curving of the first glass sheet and of an additional glass sheet, together or separately, and the laminating of the first glass sheet with an additional glass sheet using a lamination interlayer.

An item of equipment includes at least one worktop formed of at least one substrate made of monolithic glass material with a surface area of greater than 0.7 m.sup.2. The substrate exhibits a luminosity L* of greater than 10, a light transmission T.sub.L of less than 60%, and an opacity indicator of greater than 30. The item of equipment also includes at least one light source to materialize one or more zones or one or more elements or displays of the substrate. The at least one light source is positioned straight above the substrate. The item of equipment also includes at least one interface for communication with at least one element of the worktop and/or with at least one external element for wireless communication. The item of equipment is devoid of heating element(s).

Disclosed herein are opaque glass-ceramics comprising at least one nepheline crystal phase and comprising from about 30 mol % to about 65 mol % SiO.sub.2, from about 15 mol % to about 40 mol % Al.sub.2O.sub.3, from about 10 mol % to about 20 mol % (Na.sub.2+K.sub.2O), and from about 1 mol % to about 10 mol % (ZnO+MgO). Also disclosed herein are opaque-glass ceramics comprising at least one nepheline crystal phase and at least one spinel-structure phase doped with at least one colorant chosen from transition metals and rare earth elements. Further disclosed herein are methods for making these opaque glass-ceramics.