The present disclosure relates to a fluid modification system having a container structure and a plurality of independent, ceramic elements. The ceramic elements may be arranged in random orientations and contained in the container structure, thus causing a fluid flow entering the container structure at any given cross-section location to flow over the surfaces of a first subplurality of the ceramic elements, and through the porous walls of a second subplurality of the ceramic elements, before exiting at a second location of the container structure. Each one of the ceramic elements has at least one of a nanofibrous or nanoporous microstructure to enable internal flow both through a wall structure thereof, and over and around the wall structure to affect performance.

A separator element comprising a porous rigid single-piece substrate (2) presenting firstly, at its periphery, a perimeter wall (2.sub.1) that is continuous between an inlet (4) for the fluid medium for treatment at one end of the porous substrate and an outlet (5) for the retentate at the other end of the porous substrate, and secondly, internally, a surface covered by a separator layer (6) and defining an open structure made up of empty spaces (3) for passing a flow of the fluid medium for treatment. The empty spaces (3) are arranged in the porous substrate so as to create within the porous substrate a first flow network (R1) for the fluid medium for treatment, having at least two interconnected flow circuits (R1.sub.1, R1.sub.2) for the fluid medium between the inlet (4) and the outlet (5) of the porous substrate.

A porous ceramic structure intended to form the reinforcement of a ceramic matrix composite component, the structure having a connected porosity delimited by an internal surface which includes a plurality of first points, each first point being associated with a second point aligned with this first point along a normal to the internal surface taken at the first point, the structure being divisible into a plurality of unit volumes of a size less than or equal to 5 mm3 in each of which: a characteristic pore length, corresponding to the maximum of the distance separating each first point from its associated second point, is less than or equal to 0.5 mm; and a porosity ratio is greater than or equal to 50%.

A honeycomb filter includes a pillar-shaped honeycomb structure having porous partition walls provided, surrounding a plurality of cells which serve as fluid through channels extending from an inflow end face to an outflow end face, and porous plugging portions provided either at the ends on the inflow end face or the outflow end face of the cells, wherein the plugging portions are composed of a porous material, the honeycomb structure has a central region and a circumferential region, and a ratio of an area of the circumferential region with respect to that of the central region ranges from 0.1 to 0.5, a plugging length L1 in the cell extending direction of a central plugging portion in the central region is larger than a plugging length L2 of a circumferential plugging portion in the circumferential region, L1 ranges from 7 to 9 mm, and L2 from 3 to 6 mm.

A plugged honeycomb structure includes a honeycomb structure body having a porous partition wall disposed to surround a plurality of cells; and a plugging portion disposed at one end of the cells, wherein, in a section orthogonal to the extending direction of the cell, the cells each have a shape that is polygon, and one of the inflow cells and another are adjacent to each other with the partition wall therebetween, and in the section orthogonal to the extending direction of the cell, a total area of the inflow cell is larger than a total area of the outflow cell, a porosity of the partition wall is 38% or more, a thickness of the partition wall is 125 μm or more and 280 μm or less, a cell density of the honeycomb structure body is 31.0 cells/cm.sup.2 or more, and an air-permeability resistance of the partition wall is 4.5×10.sup.7Pa.Math.s/m.sup.2 or less.

A porous composite includes a porous base material and a porous collection layer formed on the base material. The collection layer has a thickness greater than or equal to 6 μm. The collection layer has a plurality of large pores, each exposing the surface of the base material. A sum of areas of exposed regions of the base material that are each exposed from each large pore of the plurality of large pores is greater than or equal to 1% of the total area of the collection layer and less than or equal to 30% thereof. This allows the porous composite to achieve a favorable efficiency of collecting particulate matter and to increase the accessible area between the particulate matter and the collection layer and thereby accelerate oxidation of the particulate matter collected by the porous composite.

An exhaust gas purification filter includes a plurality of cells extending in a filter axial direction, a porous partition separating and defining the plurality of cells, and a sealing section sealing the plurality of cells alternately at both filter ends. In the exhaust gas purification filter, the partition has a void volume of a reduced dale, Vvv, and a material volume of a reduced peak, Vmp, as volume parameters determined in noncontact surface roughness measurement on a surface of the partition, with their total value being 1.8 μm.sup.3/μm.sup.2 or less.

A honeycomb structure comprising a pillar-shaped honeycomb structure body having a porous partition wall disposed so as to surround a plurality of cells, wherein let that A denotes an absolute value of open frontal area (%) in a plane of the honeycomb structure body orthogonal to the extending direction of the cells and P denotes an absolute value of porosity (%) of the partition wall, the honeycomb structure has a value represented by the following expression (1) that is 0.05 to 0.12, let that D denotes an average pore diameter (m) of the partition wall and G denotes a geometric surface area (mm.sup.2/mm.sup.3) of the partition wall, the honeycomb structure has a value represented by the following expression (2) that is 8 to 50 (μm×mm.sup.2/mm.sup.3), and the honeycomb structure has a hydraulic diameter of the cells that is 1.1 mm or more,
(1−A/100)×(1−P/100),  Expression (1)
D×G.  Expression (2)

A honeycomb structure includes a pillar-shaped honeycomb structure body having a porous partition wall and a circumferential wall, wherein in a section orthogonal to the extending direction of the cells of the honeycomb structure body, the shape of the cell is a polygonal shape with a corner having an arc shape, a thickness T1[mm] of the partition wall is 0.0500 to 0.1400 mm, a radius of curvature R1[mm] of the corner having the arc shape of the cell and the thickness T1[mm] of the partition wall satisfy the relationship of Equation (1), in the section orthogonal to the extending direction of the cells of the honeycomb structure body, the outer diameter of the honeycomb structure body is 190.5 to 355.6 mm, and a porosity of the partition wall is 20 to 40%.

0.0050≤R1×T1≤0.0150  Equation (1):

A particulate filter 23 is configured by being provided with, arranged side by side, a plurality of honeycomb-shaped segments 29, 30, 31 having a plurality of cells 32. The density of cells in the segments 30, 31 disposed in the outer circumference part is set to be lower than the density of cells in the segments 29 disposed in the center part. In addition, the segments 30, 31 disposed in the outer circumference part are configured so that the density of the cells 32 becomes lower as the area of the end face becomes smaller.