5 research outputs found
Experimental design for the preliminary study of geochemical processes
An example of the use of a simple fuctorial design to study the distribution of /sup 134/Cs and/sup 85/Sr between a soil column and solution is reported. In this design, two concentration levels of each of four factors (NaNO/ sub 3/, HNO/sub 3/, KNO/sub 3/, and Ca(NO/sub 3//sub 2/) were combined in all possible combiuations to give a total of 24 combinations. In the case of /sup 134/Cs removal, all of the independent variables were significant over their respective concentration ranges, while with the removal of /sup 85/Sr, none of the independent variables was statistically significant. Extending the concentration range of NaNO/sub 3/ caused the NaNO/sub 3/ effect total to become statistically significant at the 5% t-test level in its effects on /sup 85/Sr removal. A fractioral factorial design was used to study the removal of Sr from solutions into an apatite during a chemical reaction between phosphate ion and calcite. The Yates analysis of the Sr removal data is tabulated. It is noted that even at a t-test level of 1%, calcite surface area, influent solution pH. and system temperaturesolution pH interaction are statistically significant. The two-level factorial design yields no direct indication of the Sr removal mechanism but does suggest that a chemical reaction is involved. (JGB