{"thcode":61,"term":{"code":521,"name":"gamma ray attenuation porosity evaluator (GRAPE)","parent":520,"scope":"a technique for estimating sample bulk density and porosity; the sample is irradiated with gamma rays, and the number of rays which pass through while maintaining their original energy (\"unattenuated\") is relative to the density (porosity is calculated using several other experimental variables)."},"uf":[],"bt":[{"code":520,"name":"density and porosity measurements","parent":519,"scope":"laboratory measurements of sediment density and porosity."},{"code":519,"name":"sediment analysis","parent":486,"scope":"laboratory analysis of sediment samples in support of a variety of geological and biological research topics (sedimentology, stratigraphy, benthic habitats, and others)."},{"code":486,"name":"laboratory methods","parent":398,"scope":"used for all laboratory procedures in support of scientific investigations."},{"code":398,"name":"research method","parent":1,"scope":null},{"code":1,"name":"Marine Realms Information Bank (MRIB) keyword categories","parent":null,"scope":null}],"nt":[],"rt":[]}