A honeycomb body having intersecting porous walls which includes first through fourth cells, wherein the cells extend from inlet to outlet face and are plugged to define a repeating structural unit with three inlets and one outlet channel. Repeating structural unit includes a first channel including length L.sub.1, width W.sub.2, and area A.sub.1, a second channel including length L.sub.2, the width W.sub.2, and area A.sub.2, a third channel including the length L.sub.1, width W.sub.1, and area A.sub.3, and a fourth channel including the length L.sub.2, the width W.sub.1, and A.sub.4, wherein the first through third channels are inlets and the fourth channel is a rectangular outlet and at least one of W.sub.1>W.sub.2 and L.sub.1L.sub.2, i.e. W.sub.1>W.sub.2, or L.sub.1L.sub.2, or W.sub.1>W.sub.2 and L.sub.1L.sub.2. Repeating structural unit has a quadrilateral outer perimeter. Particulate filters including the honeycomb body, honeycomb extrusion dies, and methods of manufacturing the honeycomb body are provided.

A method performs evaluation of properties of a clay rod, with which a honeycomb structural body is produced. The method mixes raw materials to produce a clay, and extrudes the clay and compresses the extruded clay to produce a clay rod. The method performs NMR to detect at least one of a T1 relaxation time and a T2 relaxation time in each of a normal part and an abnormality part extracted from the clay rod. Each of the T1 relaxation time and the T2 relaxation time corresponds to a relaxation time of nuclear spins of water protons magnetically excited in each of the normal part and the abnormality part. The method performs the evaluation of uniformity of a mixed state and a compression state of the clay rod based on a difference in T1 relaxation time and T2 relaxation time between the normal part and the abnormality part.

A honeycomb filter including: a pillar-shaped honeycomb structure including porous partition walls; and porous plugging portions disposed on either one of end portions of each of the cells, wherein a porosity (%) of the partition walls is defined as P1, a porosity (%) of the plugging portions is defined as P2, an occupancy (%) of the partition walls relative to an area of a cross section orthogonal to an extending direction of the cells of the honeycomb structure is defined as N1, the P1 is 50 to 65%, the P2 is 60 to 70%, the N1 is 22 to 39%, and X represented by Formula (1) satisfies a relation of Formula (2):
X=P1/P2N1,Formula (1):
18.800.19X.sup.2+11.33X121.6350.50.Formula (2):

A honeycomb structure body has a skin part of a cylindrical shape and a honeycomb structural part formed with the skin part together in a monolithic body. The skin part and the honeycomb structural part have partition walls of a porous structure. The cells have first cells arranged adjacent to the skin part and second cells arranged adjacent to the first cells. The skin part, the first cells and the second cells form an outer peripheral section. A central section is arranged inside the outer peripheral section. The honeycomb structure body satisfies a relationship in which a thermal expansion coefficient of the outer peripheral section is greater than a thermal expansion coefficient of the central section.

Provided is a honeycomb filter, including: a pillar-shaped honeycomb substrate having an inflow end face and an outflow end face and including a porous partition wall surrounding a plurality of cells; and a plugging portion disposed at any one of ends of the cells at the inflow end face and at the outflow end face. In a cross section orthogonal to an extending direction of the cells, inflow cells have a pentagonal or a hexagonal shape, and outflow cells have a square shape. The cells are configured that the inflow cells surround one outflow cell and one side of an inflow cell and one side of an adjacent outflow cell are parallel to each other. The partition wall is configured that thickness of a first partition wall disposed between the inflow cells and the outflow cells is smaller than thickness of a second partition wall disposed between the inflow cells.

A thermal shock resistant and asymmetric honeycomb ceramic wall-flow filter, comprising: an inlet honeycomb ceramic surface and an outlet honeycomb ceramic surface. Inlet channels (1) and outlet channels (2) are provided on both the inlet honeycomb ceramic surface and the outlet honeycomb ceramic surface. The inlet channels (1) are in communication with the outlet channels (2). Outlet ends of the inlet channels (1) and inlet ends of the outlet channels (2) are sealed. An inner diameter of the inlet channel (1) is greater than that of the outlet channel (2). A cross-section of the inlet channel (1) is a square, and is provided with a fillet, or two adjacent edges are connected by two connecting lines, or two adjacent edges are connected by two connecting lines or a circular arc located between the two connecting lines. A cross-section of the outlet channel (2) is a square, and is also provided with a fillet or a chamfer. The filter has good mechanical properties, low back pressure, and excellent thermal shock resistance.

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 plugged honeycomb segment includes a honeycomb segment having a quadrangular prism shape which includes porous partition walls arranged to surround a plurality of cells and an outermost circumferential wall, and a plugging portion, wherein a porosity of the partition walls is 30 to 70%, in a cross section orthogonal to the cell extending direction, an inflow cell surrounded by the partition walls is a hexagon, and an outflow cell is a square, one outflow cell is surrounded by four inflow cells, the cell located at the outermost circumference includes a complete cell and an incomplete cell, and a thickness of the outermost circumferential wall in contact with the incomplete cell (T1), a thickness of the outermost circumferential wall in contact with the complete cell (T2), and a thickness of the partition walls (WT), satisfy 0.200 mm<T1<T2(WT) and T20.700 mm.

The plugged honeycomb structure includes a plurality of honeycomb segments, a bonding layer, and plugging portions which plug open ends of cells of each honeycomb segment, and in the honeycomb segment, at least two types of cells having different sectional shapes are formed to constitute predetermined repeated arrangement patterns, and in rim circumferential wall cells including rims of the cells surrounded with partition walls and segment circumferential walls, an inflow open area of each corner rim circumferential wall cell disposed in each corner portion of the honeycomb segment is 1.1 times or more as large as an average inflow open area of non-corner rim circumferential wall cells arranged in portions other than the corner portions, or an outflow open area of the corner rim circumferential wall cell is 1.1 times or more as large as an average outflow open area of the non-corner rim circumferential wall cells.

A honeycomb structure includes a central area and a reinforced outer peripheral area. For a reference boundary cell having cell walls with different wall thicknesses on two sides parallel with an imaginary parallel line, a thin wall thickness t1<a thick wall thickness t3, an inner wall thickness t2<an outer wall thickness t4, t1=t2, and t3=t4. The honeycomb structure includes a reference cross-shaped unit having a thin wall, an inner wall, a cell wall, and a cell wall and a reference cross-shaped unit having a thick wall, an outer wall, a cell wall, and a cell wall. The honeycomb structure also includes a plurality of cross-shaped units extending vertically and horizontally from alternate cell vertexes arranged from a reference cell vertex as a starting point. In both the central area and the reinforced outer peripheral area, the cell walls of each cross-shaped unit have a substantially equal wall thickness.