Abstract: A seismic method for determining the thickness of a subterranean layer of interest and the velocity of seimic in the layer. Seismic waves are transmitted into the layer, and a plurality of waves are detected wherein each detected wave is reflected from a different point along the lower boundary of the layer. Two parameters, .DELTA.x and .DELTA.T, are determined for each reflected wave. .DELTA.x is defined as the horizontal distance a wave travels between the upper boundary and the lower boundary of the layer, and .DELTA.T is defined as the one way travel time of a wave between the upper boundary and the lower boundary of the layer. A set of data pairs are obtained, wherein each data pair includes a (.DELTA.x).sup.2 value and a (.DELTA.T).sup.2 value. These pairs are fitted to a linear function so as to yield slope value and intercept values. These values may be utilized to calculate the wave velocity and thickness of the layer.

Abstract: The instant invention is directed to the production of boards and other relatively thick-walled shapes of various configurations from inorganic silicates. The method for preparing such products involves five general steps: first a fully or predominantly crystalline body is formed containing crystals consisting essentially of a lithium and/or sodium water-swelling mica selected from the group of fluorhectorite, boron fluorphlogopite, and solid solutions therebetween; second, that body is contacted with a polar liquid, customarily water, to cause swelling and disintegration of the body accompanied with the formation of a gel; third, the gel is contacted with a source of large cations to effect an ion exchange reaction between the large cations and the Li.sup.+ and/or Na.sup.

Abstract: A fabric woven on a needle loom including a cover thread on the woven edge covering the exterior edge of the woven edge warp thread by a serpentine pattern interlocked with the weft loops and a binder thread knitted at the other edge covering the exterior edge of the knitted edge warp thread. Picot loops formed at both edges of the warp extend diagonally therefrom. A plurality of picot loops at the knitted edge include a non-picot weft loop substantially at the center of the plurality to secure the knitted binder thread to the warp edge.