Synthesis of PtZn and PtZn intermetallic nanocatalysts for dehydrogenation of ethane.

PtZn and PtZn intermetallic nanoparticles supported on SiO were synthesized by combining atomic layer deposition (ALD) of ZnO, incipient wetness impregnation (IWI) of Pt, and appropriate hydrogen reduction. The formation of PtZn and PtZn intermetallic nanoparticles was observed by both X-ray diffraction (XRD) and synchrotron X-ray absorption spectroscopy (XAS). STEM images showed that the 2-3 nm Pt-based intermetallic nanoparticles were uniformly dispersed on a SiO support.

Effect of input diffusivity in an axisymmetric mass diffusivity model for liquid metals with an applied magnetic field.

Depending on the magnitude of the diffusivity, convective contamination may result in erroneous measurement of mass diffusivity even in microgravity. The effect of natural or buoyant convection is numerically investigated for liquid germanium with an axisymmetric model using two different magnetic field strengths and four heat transfer conditions. Since the reported input diffusivity value may vary due to inaccuracies in measurements, an order of magnitude lower and higher input diffusivity from the base value of D0 = 2 x 10(-4) cm2/sec was used to evaluate the behavior of liquid germanium in the presence of a magnetic field.

Mass and thermal diffusivity algorithms: reduced algorithms for mass and thermal diffusivity determinations.

Mass and thermal diffusivity measurements conducted on Earth are prone to contamination by uncontrollable convective contributions to the overall transport. Previous studies of mass and thermal diffusivities conducted on spacecraft have demonstration the gain in precision, and lower absolute values, resulting from the reduced convective transport possible in a low-gravity environment. We have developed and extensively tested real-time techniques for diffusivity measurements, where several measurements may be obtained on a single sample.

The effects of collimator geometry and self-absorption on in-situ mass diffusion measurements.

We consider a real-time methodology for determining self-diffusion coefficients at several temperatures utilizing a single sample, based on a radiotracer technique put forth by Codastefano, Di Zanza and Russo (Codastefano, P., Di Russo, A., Zanza, V.