Radioactive tracer selective affinity for particular sites in the human body. An extensive list of radioactive tracers used in hydraulic fracturing can be found below. In metabolism research, Tritium and C-labeled glucose are commonly used in glucose clamps to measure rates of glucose uptake, fatty acid synthesis, and other metabolic processes. While radioactive tracers are sometimes still used in human studies, stable isotope tracers such as C are more commonly used in current human clamp studies. Radioactive tracers are also used to study lipoprotein metabolism in humans and experimental animals. In medicine, tracers are applied in a number of tests, such as
Hydraulic fracturing proppants impacts output rate and overall ultimate recovery of a well, commercial proppants are also constrained by cost. Transport costs from supplier to site form a significant component of the cost of proppants. Other than proppant, slickwater fracturing fluids are mostly water, generally 99% or more by volume, but gel-based fluids can see polymers and surfactants comprising as much as 7 vol% , ignoring other additives. Other common additives include hydrochloric acid (low pH can etch certain rocks, dissolving limestone for instance), friction reducers, guar gum, biocides, emulsion breakers, emulsifiers, and 2-Butoxyethanol. Radioactive tracer isotopes are sometimes included in the hydrofracturing