Pipe Creek Sinkhole have also been found there. Pipe Creek Sinkhole preserves an ancient wetland. It was created by the collapse of a limestone cave in a Silurian reef formation. That left a steep-sided depression about long, wide and deep. When water collected in the depression, it became the habitat of the plants and animals whose remains were preserved there when the sinkhole was buried by glacial outwash and till during the Pleistocene Epoch, two million to 11,000 years ago. While the ecology of the Pliocene in North America is well-known from fossil discoveries in other places, notably coastal sites, the Pleistocene glaciers
Void (composites) void content of approximately 1% is appropriate for performance while other grades of composites can have between 3%-5% void content. A small change in the percentage of void content may not seem like a large problem however for a loaded carbon fiber laminate composite, a 1%-3% increase in void content can reduce the mechanical properties of the composite by up to 20% Void content in composites is represented as a ratio, also called void ratio, where the volume of voids, solid material, and bulk volume are taken into account. Void ratio can be calculated by the formula below where e