Radioactive tracer such as a cell or tissue, or as a flow tracer to track fluid flow. Radioactive tracers are also used to determine the location of fractures created by hydraulic fracturing in natural gas production. Radioactive tracers form the basis of a variety of imaging systems, such as, PET scans, SPECT scans and technetium scans. Radiocarbon dating uses the naturally occurring carbon-14 isotope as an isotopic label. Isotopes of a chemical element differ only in the mass number. For example, the isotopes of hydrogen can be written as H, H and H, with the mass number at top left. When the
Water gel explosive nitroparaffins typically make up most of the water gel explosive. Different types of gelling agents are used to create the water gel explosive. One agent is insoluble in water, but able to gel with nitromethane. The gel used for nitromethane is cyanoethylether, a derivative of galactomannan gum. Other agents are water-soluble and are used for the aqueous salt solution. As referenced in the first paragraph, water-soluble gums and gel modifiers like guar can be used for the gelling of aqueous solutions. When the salt solution and nitroparaffin are gelled, the entire mixture is combined and mixed together until the desired