Correction to Coupling Red-Mud Ketonization of a Model Bio-Oil Mixture with Aqueous Phase Hydrogenation Using Activated Carbon Monoliths

Correction to Coupling Red-Mud Ketonization of a Model Bio-Oil Mixture with Aqueous Phase Hydrogenation Using Activated Carbon Monolith

Evaluating the thermal damage resistance of graphene/carbon nanotube hybrid composite coatings

We study laser irradiation behavior of multiwalled carbon nanotubes (MWCNT) and chemically modified graphene (rGO)-composite spray coatings for use as a thermal absorber material for high-power laser calorimeters. Spray coatings on aluminum test coupon were exposed to increasing laser irradiance for extended exposure times to quantify their damage threshold and optical absorbance. The coatings, prepared at varying mass % of MWCNTs in rGO, demonstrated significantly higher damage threshold values at 2.5 kW laser power at 10.6 μm wavelength than carbon paint or MWCNTs alone. Electron microscopy and Raman spectroscopy of irradiated specimens show that the coating prepared at 50% CNT loading endure at least 2 kW.cmˉ² for 10 seconds without significant damage. The improved damage resistance is attributed to the unique structure of the composite in which the MWCNTs act as an efficient absorber of laser light while the much larger rGO sheets surrounding them, dissipate the heat over a wider area

Chlorophyll fluorescence decay profiles of O3-exposed spruce needles as measured by time-correlated single photon counting.

Chlorophyll fluorescence decay profiles have been measured in the wavelength range 680–720 nm for needles from Norway spruce [Picea abies (L.) Karst] trees which have been exposed to ozone. All profiles required three exponential components of lifetime 100–150 ps, 400–600 ps and 3.5–5.0 ns to fit the experimental data. Compared to control samples, the ozone-treated needles exhibited a greater amount of the longest-lived chlorophyll fluorescence and a redistribution in intensity for both the other components from 720 + to 690 nm. These observations are interpreted in terms of disruption of energy transfer and break-up of light-harvesting complexes on exposure to ozone. The potential for use of the technique in monitoring forest decline is discussed