9727362 Feng This grant provides partial support of the acquisition costs of an X-ray attenuation-based particle size analyzer for the geology Department at Dartmouth College. This device measures continuous particle size distribution in samples by measuring the time varying attenuation of X-rays passing through samples as particles fall under the force of gravity through a liquid medium. The basic principle of the measurement relies on Stokes' Law of particle settling; larger particles settle more rapidly (neglecting particle shape and density variations) than smaller particles. The particle size analyzer will be used for a variety of funded research projects both for grain size analysis and as an alternative mineral separation technique. Studies of size- dependent isotopic exchange between zeolite minerals and surrounding fluids, size-dependent/surface area dependent silicate mineral weathering rates and provenance studies of marine sediments will take advantage of the instruments ability to rapidly measure continuous grain size distributions over a wide range of silt and clay sized particles (100 microns-10 nm). Several researchers at Dartmouth will make use of this equipment and will involve undergraduate students in the analytical phases of their respective research programs. ***
