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Use of experimental design in detergency tests with a natural soil
Author(s) -
Trowbridge James R.
Publication year - 1971
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02544568
Subject(s) - rubbing , sodium , chemistry , block (permutation group theory) , mathematics , geometry , organic chemistry
A balanced incomplete block design is used to obtain detergency data in a test where cloth swatches are soiled by rubbing against the skin. The design provides increased precision in the data by adjusting for differences among soilers. The wash treatments are part of a second order rotatable design in three variables: the ratio of sodium nitrilotriacetate to sodium tripolyphosphate builder, pH of the wash solution, and temperature. The effect of builder ratio was not highly significant. Soil removal increased with higher pH and went through a maximum with increase in wash temperature. Redeposition was also measured by reflectance values obtained for unsoiled areas of the swatches. Redeposition increased with increase in wash temperature.