	US 7,571,061 B2
	Non-destructive method of measuring a moisture content profile across a hygroexpansive, composite material
Zhiyong Cai, Madison, Wis. (US)
Assigned to The United States of America as represented by the Secretary of Agriculture, Washington, D.C. (US)
Filed on Mar. 28, 2008, as Appl. No. 12/79,868.
Claims priority of provisional application 60/923946, filed on Apr. 17, 2007.
Prior Publication US 2008/0262752 A1, Oct. 23, 2008
Int. Cl. G06F 19/00 (2006.01); G01B 15/00 (2006.01)

U.S. Cl. 702—40 [702/155]

31 Claims

1. A non-destructive method of measuring a moisture content in a hygroexpansive material, the method comprising:

selecting a hygroexpansive, composite material having an amount of water that results in a hygroexpansive state of the material;

selecting a radiation source for emitting electromagnetic radiation into an entry surface of the composite material; wherein the radiation has an intensity that is sufficient to penetrate through a depth of the composite material, a portion of the radiation is absorbed by the composite material, and a remainder of the radiation is transmitted from an exit surface of the composite material; wherein the distance between the entry surface and the exit surface is the depth of the composite material that was penetrated by the electromagnetic radiation;

measuring a density of the composite material in the hygroexpansive state, wherein the density is obtained by (i) passing the radiation through the composite material and (ii) measuring the amount of absorbed radiation, wherein the amount of absorbed radiation provides the density of the composite material in the hygroexpansive state;

measuring a baseline density of a representative sample of the composite material in a water-free state, wherein the density is obtained by passing the radiation through the representative sample and measuring the amount of absorbed radiation, wherein the amount of absorbed radiation provides the density of the composite material in the water-free state;

determining a volumetric shrinkage of the representative sample that occurs during the removal of the amount of water from the representative material; and,

calculating a moisture content of the composite material in the hygroexpansive state, wherein the calculating includes using (1) the density of the composite material in the hygroexpansive state, (2) the density of the representative sample in the water-free state, and (3) the volumetric shrinkage of the representative sample in the water-free state.