A filter including a plurality of pillar-shaped honeycomb structure segments made of porous ceramics, side faces of the segments being bonded together via a bonding material, wherein each of the pillar-shaped honeycomb structure segments includes an outer peripheral side wall, and partition walls partitioning a plurality of cells extending from a first end face to a second end face, and in each of the pillar-shaped honeycomb structure segments, an average porosity of the outer peripheral side wall is lower than that of the partition walls.

A molded three-dimensional insulator that is suitable for use in an end cone region of a pollution control device and a method of making the insulator are described. The insulator includes ceramic fibers that have a bulk shrinkage no greater than 10 weight percent. The ceramic fibers can contain alumina and silica and can be microcrystalline, crystalline, or a combination thereof.

A molded three-dimensional insulator that is suitable for use in an end cone region of a pollution control device and a method of making the insulator are described. The insulator includes ceramic fibers that have a bulk shrinkage no greater than 10 weight percent. The ceramic fibers can contain alumina and silica and can be microcrystalline, crystalline, or a combination thereof.

A ceramic honeycomb body having a skin that does not block partial cells extending from an inlet face to an outlet face at an outer periphery portion of the body. A method of making the ceramic honeycomb body having the skin includes disposing a sheet on an outer peripheral wall of a honeycomb core having an outer surface spaced apart from interiors of the partial cells and skinning the body having the sheet disposed thereon. Subsequent curing in the method bonds the skin to cell walls of the body spaced apart from interiors of the partial cells.

A ceramic honeycomb body having a skin that does not block partial cells extending from an inlet face to an outlet face at an outer periphery portion of the body. A method of making the ceramic honeycomb body having the skin includes disposing a sheet on an outer peripheral wall of a honeycomb core having an outer surface spaced apart from interiors of the partial cells and skinning the body having the sheet disposed thereon. Subsequent curing in the method bonds the skin to cell walls of the body spaced apart from interiors of the partial cells.

The honeycomb structure includes a pillar-shaped honeycomb structure body, and a circumferential coating layer disposed to surround a circumference of the honeycomb structure body, and cells which are formed at an outermost circumference of the honeycomb structure body and in which peripheries of the cells are defined by the partition walls without any lacks are defined as outermost circumference complete cells, and in a cross section of the honeycomb structure body which is perpendicular to an extending direction of the cells a minimum distance T (mm) among distances from the outermost circumference complete cells to the surface of the circumferential coating layer and a porosity P (%) of the circumferential coating layer satisfy relations of Equation (1) and Equation (2) as follows:
1.5T16(100P).sup.1.4; andEquation (1):
20P75Equation (2).

The honeycomb structure includes a pillar-shaped honeycomb structure body, and a circumferential coating layer disposed to surround a circumference of the honeycomb structure body, and cells which are formed at an outermost circumference of the honeycomb structure body and in which peripheries of the cells are defined by the partition walls without any lacks are defined as outermost circumference complete cells, and in a cross section of the honeycomb structure body which is perpendicular to an extending direction of the cells a minimum distance T (mm) among distances from the outermost circumference complete cells to the surface of the circumferential coating layer and a porosity P (%) of the circumferential coating layer satisfy relations of Equation (1) and Equation (2) as follows:
1.5T16(100P).sup.1.4; andEquation (1):
20P75Equation (2).

In a porous body, a surface layer thickness Ts takes a relatively small value satisfying P0.54 Ts (formula (1)), the surface layer thickness Ts being derived by a microstructure analysis using the porous-body data that is prepared through three-dimensional scanning of a region including a surface (inflow plane 61) of the porous body. Here, P denotes a porosity [%] of the porous body, and 0%<P<100% and 0 m<Ts are assumed. The surface layer thickness Ts is derived as a distance in a thickness direction (X direction) between a surface-layer region start plane 92 in which a straight-pore opening ratio becomes 98% or less for the first time and a surface-layer region end plane 93 in which the straight-pore opening ratio becomes 1% or less for the first time.

In a porous body, a surface layer thickness Ts takes a relatively small value satisfying P0.54 Ts (formula (1)), the surface layer thickness Ts being derived by a microstructure analysis using the porous-body data that is prepared through three-dimensional scanning of a region including a surface (inflow plane 61) of the porous body. Here, P denotes a porosity [%] of the porous body, and 0%<P<100% and 0 m<Ts are assumed. The surface layer thickness Ts is derived as a distance in a thickness direction (X direction) between a surface-layer region start plane 92 in which a straight-pore opening ratio becomes 98% or less for the first time and a surface-layer region end plane 93 in which the straight-pore opening ratio becomes 1% or less for the first time.

A method of excluding particles entrained in formation fluids includes introducing a tubular into a wellbore, forming a sand control device formed from a curable inorganic cementitious mixture infused with an engineered degradable material about the tubular, introducing an external stimulus onto the sand control device causing the degradable material to dissolve, and flowing formation fluids through the sand control device into the tubular.