An apparatus for viewing in a structure having a first participant and at least a second participant having a first VR headset to be worn by the first participant, and a second VR headset to be worn by the second participant. Each participant sees every other participant in the structure as every other participant physically appears in the structure in real time in a simulated world displayed about them by the respective VR headset each participant is wearing. Each participant sees the simulated world from their own correct perspective in the structure. The simulated world includes a near field and a far field. A method for a first participant and at least a second participant viewing in a structure.

The invention relates to a method of manufacturing a ceramic molding, comprising the following steps: a) providing three or more ceramic powder layers that are arranged in layers, one on top of the other, to form a compression-molded element and sintering the compression-molded element obtained in step b) to form a ceramic molding, characterized in that the ceramic powder layers have different compositions, each ceramic powder layer comprising a mixture of at least two different base powders and each base powder containing at least 80 wt. % ZrO.sub.2 and at least 0.02 wt. % Al.sub.2O.sub.3, each weight amount being relative to the total weight of the constituents of the base powder.

The invention relates to a sintered molding with a color gradient for use in the manufacture of dental restorations, obtainable by sintering a compression-molded element comprising five or more different ceramic powder layers, each powder layer comprising at least two different base powders and each base powder containing at least 80 wt. % ZrO.sub.2, each weight amount being relative to the total weight of the base powder.

The invention relates to multi-layer oxide ceramic bodies and in particular to presintered multi-layer oxide ceramic blanks and oxide ceramic green bodies suitable for dental applications. These bodies can be thermally densified by further sintering without distortion and are thus particularly suitable for the manufacture of dental restorations. The invention also relates to a process for the manufacture of such multi-layer oxide ceramic bodies as well as to a process for the manufacture of dental restorations using the multi-layer oxide ceramic bodies.

A composite transparent film, a preparation method thereof and a method for continuous digital light processing ceramic 3D printing based on the same are provided. The method selects a mixture of silica microspheres and PDMS to form a composite film on which silica is used to form a hydrophobic layer. Combined with specific optimized parameters, the film is more suitable for continuous digital light processing ceramic 3D printing, which can realize the continuous printing of ceramic slurries, solve the problem of delamination of printed pieces obtained by the existing 3D printing method of ceramics, improve the printing accuracy, and decrease the printing costs.

Disclosed are a composite gypsum board and a method of preparing composite gypsum board. The board contains a set gypsum core sandwiched between two cover sheets. The core is formed from a slurry containing stucco, water, and optional ingredients such as foaming agent, accelerator, retarder, polyphosphate, starch, and dispersant, and core intumescent material. The board also contains at least one skim coat and/or hard edges. A face skim coat layer can be included on one side of the core, facing a face cover sheet. A back skim coat layer can be included on the other side of the core, facing a back cover sheet. Hard edges are known in the art and can be formed, e.g., continuously from a stucco slurry for forming the face and/or back skim coats. Preferably, the back skim coat layer and/or the hard edges are formed from a slurry containing stucco, water, skim coat or edge intumescent material (which have the same desired characteristics), and other optional additives as desired. The skim coat or edge intumescent material can be composed of the same material as the core intumescent material, if desired, but the skim coat and/or edge intumescent material is present in a higher relative concentration in its respective slurry than the amount of core intumescent material in the core slurry. Examples of suitable intumescent materials include expandable vermiculite (e.g., No. 4 or No. 5 according to the US naming system, or combinations thereof), expandable graphite, perlite, or any combination thereof.

A method for the layered production of a green body (10) from powdery material, including insert elements which are placed at defined positions in the powdery material, in which the green body (10) is segmented in a building direction (16) into N, N≥2 consecutive, cylindrical cross-sectional areas (11, 12, 13, 14, 15) made up of a two-dimensional cross-sectional surface and a layer thickness. Setting areas for the insert elements are defined in the cross-sectional areas of the green body (10) which include the defined positions for the insert elements, and loose powder particles surrounding the setting elements are at least partially bonded to each other before the insert elements are placed into the powdery material.

A method for the layered production of a component (10) from powdery material including loose powder particles, based on three-dimensional data of the component (10), including the method steps: the component (10) is segmented in a building direction (16) into N, N≥2 consecutive, cylindrical cross-sectional areas (11, 12, 13, 14, 15) made up of a two-dimensional cross-sectional surface and a layer thickness; N powder layers of the powdery material are applied to a building plane perpendicular to the building direction (16); the loose powder particles in the cross-sectional areas (11, 12, 13, 14, 15) of the component (10) are at least partially bonded to each other and to the underlying cross-sectional area and; loose powder particles arranged within one cross-sectional area or within multiple consecutive cross-sectional areas in the building direction (16) are at least partially removed from the component (10) during the layered production of the component (10).

One aspect of the present disclosure relates to devices for sealing gaps in an extrusion assembly to provide for a consistent extrusion. In one embodiment, a barrel-shaped sealing device with a resilient protruding edge is used to prevent extrusion material from entering gaps between the piston and the inner surface of the barrel. The sealing device includes a fastener to releasably attach the sealing device to the piston. Sealing rings are inserted into a bottom gap formed between the bottom edge of the barrel and the bottom surface of the die.

A fiber-reinforced prestressed reinforced concrete sleeper is integrally cast and includes a sleeper body and two rail bearing regions. A rail clamping base is arranged on a surface of the each rail bearing region. The two rail bearing regions are located under rails on both sides of the sleeper and the two rail bearing regions are located above the sleeper body. A reinforcing fiber is mixed into the two rail bearing regions only, and a reinforcing rib is arranged in the sleeper body. The reinforcing fiber is concentrated in a main stress region under the surface of the rail bearing regions. The reinforcing fiber arranged in a region with a large stress is more than the reinforcing fiber arranged in a region with a small stress.