Methods for repairing composite cylindrical components are provided. One exemplary method for repairing a cylindrical component defining an axial direction, a radial direction, and a circumferential direction includes removing a damaged region of the cylindrical component. A flange extending from a cylindrical body of the cylindrical component is included in the damaged region. One or more arc segments that extend along the circumferential direction are connected with the existing cylindrical component. At least one of the arc segments includes a prefabricated flange. One or more plies are laid up to connect the arc segments with the existing cylindrical component to repair the damaged region of the cylindrical body and the prefabricated flange formed integrally with one of the arc segments replaces the damaged portion of the flange. Repaired cylindrical components are also provided.

An extended length tube structure includes a first ceramic tube segment having a first end and a second end, and a second ceramic tube segment having a first end and a second end, in which the second end of the first ceramic tube segment is arranged to face the first end of the second ceramic tube segment. A ceramic coupling component is positioned to circumscribe the end-to-end configuration of the tube segments, and is sinter-bonded to the tube segments to form a continuous, extended length tube structure having a seal, such as a sinter bond or an interference bond, that is free of bond materials.

A system for producing chemicals, such as, ethylene or gasoline, at high temperature (above 1100 degrees C.) having a feedstock source. The system includes a chemical conversion portion connected with the feedstock source to receive feedstock and convert the feedstock to ethylene or gasoline. The conversion portion includes a coil array and a furnace that heats the feedstock to temperatures in excess of 1100 C. or 1200 C. or even 1250 C. or even 1300 C. or even 1400 C. A method for producing chemicals, such as ethylene or gasoline, at high temperature.

A system for producing chemicals, such as, ethylene or gasoline, at high temperature (above 1100 degrees C.) having a feedstock source. The system includes a chemical conversion portion connected with the feedstock source to receive feedstock and convert the feedstock to ethylene or gasoline. The conversion portion includes a coil array and a furnace that heats the feedstock to temperatures in excess of 1100 C. or 1200 C. or even 1250 C. or even 1300 C. or even 1400 C. A method for producing chemicals, such as ethylene or gasoline, at high temperature.

An assembly including a ceramic body. The assembly comprises a tungsten coupling attached to the ceramic body with a first joint that forms a first helium tight seal between the ceramic body and the tungsten coupling and where the first helium tight seal maintains its integrity at a temperature over 400 C. The assembly includes a metal body attached to the tungsten coupling with a second joint that forms a second helium tight seal between the metal body and the tungsten coupling and where the second helium tight seal maintains its integrity at a temperature over 400 C. A method. A mixture. A coupling.

A polycrystalline CaF.sub.2 member includes a combined assembly of a plurality of polycrystalline bodies made from CaF.sub.2 that are pressure bonded together.

Refractory components (e.g. crown or rider arches associated with a refractory structure such as coke ovens, glass furnaces, regenerators and the like) are provided by multiple refractory members bonded to one another by a bonding agent to form an integral self-supporting structure.

A ceramic component is formed of at least one stack of two or more layers of one-directional non-woven carbon fiber fabrics embedded in a ceramic matrix containing silicon carbide and elemental silicon. All adjacent layers within the at least one stack directly adjoin each other. The at least one stack has a minimum thickness of 1.5 mm perpendicularly to the plane of the layers. The ceramic matrix permeates substantially the entire component.

A ceramic bonded body of the disclosure includes a first silicon carbide ceramics, a second silicon carbide ceramics, and a bonding layer positioned between the first silicon carbide ceramics and the second silicon carbide ceramics. The bonding layer contains 25 mass % or more metallic silicon, and 25 mass % or more silicon carbide assuming all components constituting the bonding layer as 100 mass %, and a total of the metallic silicon and the silicon carbide is 75 mass % or more, and the bonding layer further contains at least one of nickel silicide and chromium silicide.

A honeycomb structure including prismatic columnar honeycomb segments and a bonding layer, wherein the bonding layer has rows in each of which bonding layer portions each disposed between two honeycomb segments arranged to face each other are arranged to extend from one point of a peripheral edge of a bonded body of the honeycomb segments to the other point thereof, in a cross section, the bonding layer of each of the-rows is disposed so that among the bonding layer portions arranged in one direction, an outermost circumference bonding layer portion and at least one of the other bonding layer portions are not superimposed on each other on an extension line of the one direction, and a ratio of shift of side surfaces of adjacent honeycomb segments to a length of one side of a side surface of honeycomb segments having the same cross-sectional shape is 10% or less.