F wave. In neuroscience, an F wave is the second of two voltage changes observed after electrical stimulation is applied to the skin surface above the distal region of a nerve. F waves are often used to measure nerve conduction velocity, and are particularly useful for evaluating conduction problems in the proximal region of nerves (i.e., portions of nerves near the spinal cord).
The success of the first permanent bobsleigh, luge, and skeleton track in KÃ¶nigssee, West Germany, completed in 1968 and first used for the world luge championships the following year, also played a factor. [7] [8] In 1969, it was decided to construct a permanent facility in Oberhof. [9]
In 1877 the world's first crochet machine was invented and patented by Joseph M. Merrow, then-president of what had started in the 1840s as a machine shop to develop specialized machinery for the knitting operations. This crochet machine was the first production overlock sewing machine.n 1804, a sewing machine was built by the Englishmen Thomas Stone and James Henderson, and a machine for embroidering was constructed by John Duncan in Scotland. An Austrian tailor, Josef Madersperger, began developing his first sewing machine in 1807. He presented his first working machine in 1814.