Abstract: The disclosed technology relates to a ceramic composite which is able to withstand temperatures in excess of 2200° F. on a repeated basis without cracking due to thermal shock. The composite may comprise a web of reinforcement fibers; and a matrix that substantially embeds the web. The composite may be formed by impregnating the web with a sol containing alumina and, in some cases, rare earth oxides, and firing the impregnated web. The web may be a three-dimensional orthogonal weave of the reinforcement fibers. The fibers may comprise a transitional phase alumina. The composite may be essentially free of Group I and Group II metals and transition metal oxides. The composite may be used as a refractory brick or lining and may also be used as an insulating material due to its chemically non-reactive nature.

Abstract: Apparatus and methods suitable for electromagnetic ablation of targeted tissue provide for improved control over ablation size and shape. In various embodiments, a plurality of dispersive electrodes may be arranged in a circumferential manner in close proximity to a targeted tissue region. The dispersive electrodes may be individually controlled to alternately enable/disable the electrodes to provide for different current paths between an active electrode and one or more of the dispersive electrodes. Other embodiments are described and claimed.

Abstract: A ceramic composite is able to whithstand temperatures in excess of 2200 F on a repeated basis without cracking due to thermal shock. The composite has a web of reinforcement fibers; and a matrix that substantially the web after the firing step. The matrix is formed around the web by impregnating the web with a sol containing alumina and, in some cases, rare earth oxides, and firing the composite after the impregnation. The web may be a three-dimensional orthogonal weave of the reinforcement fibers, where the fibers are a transitional phase alumina. The composite is essentially free of Group I and Group II metals and transition metal oxides. The composite may be used as a refractory brick or lining and may also be used as an insulatingmaterial due to its chemically non-reactive nature.