Charles L. Collins

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Alkali-silica reaction (ASR) occurs in concrete between reactive siliceous components in the aggregate and the strongly alkaline pore solution, resulting in the formation of a potentially expansive gel product. Lithium additives have been shown to reduce expansion associated with ASR, but the mechanism(s) by which lithium reduces expansion have not been(More)
We applied a simple, sensitive differential absorption technique to measure the two-photon cross section for the 5(2)S((1/2))(F(g) = 2) ? 5(2)D(5/2)(F(e) = 4) hyperfine transition in (85)Rb [sigma((2)) = (1.2 +/- 0.5) x 10(-18) cm(4)/W]. The detection circuit permitted straightforward measurements close to the shot-noise limit. Detailed quantitative(More)
At the Centers for Disease Control (CDC), educational activities concerning acquired immunodeficiency syndrome (AIDS) are directed to many target audiences; important among these are health care and public safety workers. Several CDC programs are designed to address the specific education and training needs of these groups. The National Institute for(More)
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