Gas detector in industrial refrigeration processes and biological degradation processes, including exhaled breath. Depending on the required sensitivity, different types of sensors are used (e.g., flame ionization detector, semiconductor, electrochemical, photonic membranes). Detectors usually operate near the lower exposure limit of 25ppm; however, ammonia detection for industrial safety requires continuous monitoring above the fatal exposure limit of 0.1%. There are several different sensors that can be installed to detect hazardous gases in a residence. Carbon monoxide is a very dangerous, but odorless, colorless gas, making it difficult for humans to detect. Carbon monoxide detectors can be purchased for around US$20–60. Many local
Lawn mower racing engines and chassis from regular model mowers. Also, where go-karts are exclusively raced on relatively flat surfaces, lawn mowers can be raced off-road. Since the summer of 1984, the North Wilkesporo Rotary Club has played host to lawnmower racing at its Wilkes County Agricultural Fairground facility. Sanctioned by the Allegheny Mower Racing Association, oval track racing on the dirt is reminiscent of the beginnings of stock car racing at the North Wilkesboro Speedway and the birth of NASCAR. Crowds have grown from a few hundred to gatherings of thousands on several Saturday nights from June through September. The Wilkes County