Compositions – Nonreactive analytical – testing – or indicating compositions
Reexamination Certificate
2008-01-01
2008-01-01
Corcoran, Gladys J P (Department: 1744)
Compositions
Nonreactive analytical, testing, or indicating compositions
Reexamination Certificate
active
07314582
ABSTRACT:
The present invention discloses a lanthanide-halide based humidity indicator and method of producing such indicator. The color of the present invention indicates the humidity of an atmosphere to which it is exposed. For example, impregnating an adsorbent support such as silica gel with an aqueous solution of the europium-containing reagent solution described herein, and dehydrating the support to dryness forms a substance with a yellow color. When this substance is exposed to a humid atmosphere the water vapor from the air is adsorbed into the coating on the pore surface of the silica gel. As the water content of the coating increases, the visual color of the coated silica gel changes from yellow to white. The color change is due to the water combining with the lanthanide-halide complex on the pores of the gel.
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Beitz James V.
Williams Clayton W.
Corcoran Gladys J P
Dobbs Michael J.
Gottlieb Paul A.
Lally Brian J.
U.S. Department of Energy
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