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 mower are: Extensive grass trimming was not common before the widespread application of the vertical shaft single cylinder gasoline/petrol engine. In the United States this development paralleled the market penetration of companies such as the Briggs & Stratton company of Wisconsin. Most rotary push mowers are powered by internal combustion engines. Such engines are usually four-stroke engines, used for their greater torque and cleaner combustion (although a number of older models used two-stroke engines), running on gasoline (petrol) or other liquid fuels. Internal combustion engines used with lawn mowers normally have only one cylinder. Power generally ranges from four to