The present invention addresses the problem of providing: a porous carbon structure that has a high micropore volume and can be self-contained; a manufacturing method therefor; a positive electrode material using the same; and a battery (particularly an air battery) using the same. The present invention is a porous carbon structure that is for a positive electrode for an air battery and has voids and a skeleton formed by incorporating carbon, the porous carbon structure satisfying all of the following conditions (a) to (d). (a) The t-plot external specific surface area is within the range of 300m.sup.2/g to 1600m.sup.2/g; (b) the total volume of micropores having a diameter of lnm to 200 nm is within the range of 1.2 cm.sup.3/g to 7.0cm.sup.3/g; (c) the total volume of micropores having a diameter of lnm to 1000 nm is within the range of 2.3cm3/g to 10.0 cm.sup.3/g; and (d) the overall porosity is within the range of 80% to 99%.

The present invention addresses the problem of providing: a porous carbon structure that has a high micropore volume and can be self-contained; a manufacturing method therefor; a positive electrode material using the same; and a battery (particularly an air battery) using the same. The present invention is a porous carbon structure that is for a positive electrode for an air battery and has voids and a skeleton formed by incorporating carbon, the porous carbon structure satisfying all of the following conditions (a) to (d). (a) The t-plot external specific surface area is within the range of 300m.sup.2/g to 1600m.sup.2/g; (b) the total volume of micropores having a diameter of lnm to 200 nm is within the range of 1.2 cm.sup.3/g to 7.0cm.sup.3/g; (c) the total volume of micropores having a diameter of lnm to 1000 nm is within the range of 2.3cm3/g to 10.0 cm.sup.3/g; and (d) the overall porosity is within the range of 80% to 99%.

The present disclosure provides an aerogel composition which is durable and easy to handle, which has favorable performance in aqueous environments, and which also has favorable combustion and self-heating properties. Also provided is a method of preparing an aerogel composition which is durable and easy to handle, which has favorable performance in aqueous environments, and which has favorable combustion and self-heating properties. Further provided is a method of improving the hydrophobicity, the liquid water uptake, the heat of combustion, or the onset of thermal decomposition temperature of an aerogel composition.

The present disclosure provides an aerogel composition which is durable and easy to handle, which has favorable performance in aqueous environments, and which also has favorable combustion and self-heating properties. Also provided is a method of preparing an aerogel composition which is durable and easy to handle, which has favorable performance in aqueous environments, and which has favorable combustion and self-heating properties. Further provided is a method of improving the hydrophobicity, the liquid water uptake, the heat of combustion, or the onset of thermal decomposition temperature of an aerogel composition.

Provided are ceramic foams. The ceramic foams may have a hierarchical pore gradient. The ceramic foams may be silica aerogels. The ceramic foams may be made by reaction of one or more precursors in the presence of an inert gas generated by a pore-forming gas-forming additive. The ceramic foams may be used as insulating materials.

Provided are ceramic foams. The ceramic foams may have a hierarchical pore gradient. The ceramic foams may be silica aerogels. The ceramic foams may be made by reaction of one or more precursors in the presence of an inert gas generated by a pore-forming gas-forming additive. The ceramic foams may be used as insulating materials.

A honeycomb structure includes: an outer peripheral wall; and partition walls disposed on an inner side of the outer peripheral wall, the partition walls defining a plurality of cells, each of the plurality of cells extending from one end face to the other end face to form a flow path for a fluid. The partition walls and the outer peripheral wall include ceramics containing at least silicon. A content of silicon in the ceramics is 30% by mass or more. A concentration of at least one dopant in the silicon is from 10.sup.16 to 5×10.sup.20/cm.sup.3.

A honeycomb structure includes: an outer peripheral wall; and partition walls disposed on an inner side of the outer peripheral wall, the partition walls defining a plurality of cells, each of the plurality of cells extending from one end face to the other end face to form a flow path for a fluid. The partition walls and the outer peripheral wall include ceramics containing at least silicon. A content of silicon in the ceramics is 30% by mass or more. A concentration of at least one dopant in the silicon is from 10.sup.16 to 5×10.sup.20/cm.sup.3.

Disclosed is a method and system for blending a foam modifier with foaming agent on-line, e.g., as may be particularly useful for gypsum or cement slurries. The foam modifier comprises a fatty alcohol that is added to a gypsum or cement slurry that includes foaming agent, such as an alkyl sulfate surfactant. The fatty alcohol can be a C.sub.6-C.sub.16 fatty alcohol in some embodiments. The use of such a foam modifier can be used, for example, to stabilize the foam, reduce waste of foaming agent, improve void size control in the final product, and improve the gypsum board manufacturing process.

Disclosed is a method and system for blending a foam modifier with foaming agent on-line, e.g., as may be particularly useful for gypsum or cement slurries. The foam modifier comprises a fatty alcohol that is added to a gypsum or cement slurry that includes foaming agent, such as an alkyl sulfate surfactant. The fatty alcohol can be a C.sub.6-C.sub.16 fatty alcohol in some embodiments. The use of such a foam modifier can be used, for example, to stabilize the foam, reduce waste of foaming agent, improve void size control in the final product, and improve the gypsum board manufacturing process.