There is provided a zeolite having a CHA structure. When a total integrated intensity of a (211) plane, a (104) plane, and a (220) plane in an X-ray diffraction spectrum obtained by an X-ray powder diffraction method is defined as X.sub.0 and the total integrated intensity after heat endurance test for five hours at 900 C. under an air atmosphere is defined as X.sub.1, a ratio of X.sub.1 (X.sub.1/X.sub.0) to X.sub.0 is within a range from 0.2-0.7; and as measured by a .sup.27Al-NMR method after the heat endurance test for five hours at 900 C. under the air atmosphere, when a peak intensity of tetra-coordinated Al atoms is defined as P.sub.4 and a peak intensity of hexa-coordinated Al atoms is defined as P.sub.6, a ratio of P.sub.6 (P.sub.6/P.sub.4) to P.sub.4 is 0.1 or less.

A method for plugging a subset of cells of a honeycomb structure that includes: covering a first end face of the honeycomb structure with a mask that comprises a body and a plurality of openings, wherein the plurality of openings of the mask is coincident with a plurality of cells of the honeycomb structure; providing a plug of material upon a film material; applying a force to the film material to push the plug of material through the plurality of openings of the mask and into the plurality of cells of the honeycomb structure; and measuring a pressure within the plurality of cells during the applying step, wherein the applying step further comprises adjusting the force applied to the film material based at least in part on the pressure within the plurality of cells to push the plug of material to a predetermined depth within the plurality of cells.

A compression jaw assembly unit for a compressing device for compressing tubular metal parts includes a compression jaw carrier (17) and a compression jaw (16), provided at the compression jaw carrier (17), with a compressing surface (18) that is oriented essentially facing away from the compression jaw carrier (17) and is curved transversely to a compression jaw longitudinal direction (L.sub.B) in a compression jaw transverse direction (Q.sub.B). The compression jaw (16) includes a fixed compression jaw segment (22), which is fixed to the compression jaw carrier (17) and provides a compressing surface segment (24), and at least one movable compression jaw segment (26, 28) providing a compressing surface segment (30, 32). The at least one movable compressing surface segment (26, 28) can be moved in a direction of movement (B) in relation to the fixed compressing surface segment (22) against the prestressing action of a prestressing device (42).

An article, includes a porous ceramic honeycomb body and a housing disposed on at least one of an outer periphery of the porous ceramic honeycomb body and opposing end faces of the porous ceramic honeycomb body, wherein the housing exerts a compressive force on the porous ceramic honeycomb body in at least one of radial direction and axial direction. A method of making the article, includes heating to greater than or equal to about 200 C the housing, crimping the housing tightly around the honeycomb body while the housing is greater than or equal to about 200 C, and cooling the housing. The housing exerts a compressive force on the porous ceramic honeycomb body in at least one of radial direction and axial direction by shrinking on cooling more than the honeycomb body.

Provided is a holding material for an exhaust gas treatment apparatus having excellent heat resistance, excellent initial contact pressure, and excellent holding property which ensures that a high contact pressure can be maintained even after repeated compression, and thus a holding ability can be effectively maintained even in long time use. The holding material for an exhaust gas treatment apparatus is arranged in a gap between an exhaust gas treatment material and a casing containing the exhaust gas treatment material, and is in the form of a wet molded product containing inorganic fibers and having a weight per unit area of 1600 to 3000 g/m.sup.2 and a bulk density of 0.125 to 0.205 g/cm.sup.3.

In one embodiment, there is disclosed an apparatus for decontaminating exhaust gasses. The apparatus includes a monolith catalytic substrate having a length and a width. The substrates length separates first and second opposed ends. The first end and second ends each have a one piece retention ring fitted thereon. The apparatus includes a housing having a length separating opposed, spaced apart open first and second ends. The housing has a side wall extending substantially unbroken there between to define a body having an interior space. The monolith catalytic substrate is disposed in said interior space. The housing has a greater length than said monolith catalytic substrate. The substrate is centered in the housing and the housing is swaged at the first and second ends respectively to engage the retention rings and retain the monolith catalytic substrate within the interior space in said housing.

Exhaust gas treatment articles and methods of manufacturing the same are disclosed herein. An exhaust gas treatment article includes a porous ceramic honeycomb body with multiple channel walls defining cell channels that extend in an axial direction and an outer peripheral surface that extends in the axial direction. The exhaust gas treatment article further includes a metal layer that surrounds the porous ceramic honeycomb body and that is in direct contact with at least a portion of the outer peripheral surface of the porous ceramic honeycomb body. The metal layer includes a joint. The exhaust gas treatment article includes a shim that is located under the joint and that is in direct contact with at least a portion of the outer peripheral surface of the porous ceramic honeycomb body.

A retention material for a gas processing device including a processing structure and a casing for accommodating the processing structure, the retention material including inorganic fibers and being arranged between the processing structure and the casing, wherein in a test of repeating a cycle of compressing the retention material until a bulk density of the retention material becomes a prescribed compression bulk density, followed by retaining for 10 seconds, and then releasing until a bulk density of the retention material becomes a release bulk density that is smaller by 12% of said prescribed compression bulk density; a release surface pressure of the retention material after repeating the cycle 2500 times and the compression bulk density of the retention material satisfies the relationship, P17.10D1.62 wherein P is the release surface pressure (N/cm.sup.2) and D is the compression bulk density (g/cm.sup.3).

An exhaust system includes an exhaust gas treatment article having a porous ceramic honeycomb body mounted in a housing. The housing can be a low expansion housing and includes an outer shell having a first coefficient of thermal expansion (CTE) and an inner wall having a second CTE greater than the first CTE configured to hold the honeycomb body over operating temperatures.

An exhaust-gas component, having across-sectionallyrectangular arrangement composed of at least onecross-sectionallyrectangular exhaust-gas aftertreatment element; and a housing which engages around thecross-sectionallyrectangular arrangement. The housing has a rectangular cross section and is divided, along a diagonal of the cross section, into two housing parts. The housing is arranged under compressive stress in an external housing.