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This study investigated the physical properties of water-blown rigid polyurethane (PU) foams made from VORANOLV R 490 (petroleum-based polyether polyol) mixed with 0-50% high viscosity (13,000-31,000 cP at 22 C) soy-polyols. The density of these foams decreased as the soy-polyol percentage increased. The compressive strength decreased, decreased and then increased, or remained unchanged and then increased with increasing soy-polyol percentage depending on the viscosity of the soy-polyol. Foams made from high viscosity (21,000-31,000 cP) soy-polyols exhibited similar or superior density-compressive strength properties to the control foam made from 100% VORNAOLV R 490. The thermal conductivity of foams containing soy-polyols was slightly higher than the control foam. The maximal foaming temperatures of foams slightly decreased with increasing soy-polyol percentage. Micrographs of foams showed that they had many cells in the shape of sphere or polyhedra. With increasing soy-polyol percentage, the cell size decreased, and the cell number increased. Based on the analysis of isocyanate content and compressive strength of foams, it was concluded that rigid PU foams could be made by replacing 50% petroleum-based polyol with a high viscosity soy-polyol resulting in a 30% reduction in the isocyanate content.

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Achieving complete oxidation, good humidity tolerance and low energy cost is the key issue that needs to be addressed in plasma catalytic volatile organic compounds removal from air. For this purpose, Ag/HZSM-5 catalyst-packed dielectric barrier discharge using a cycled system composed of a storage stage and a discharge stage was studied. For dilute benzene removal from simulated air, Ag/HZSM-5 catalysts exhibit not only preferential adsorption of benzene in humid air at the storage stage but also almost complete oxidation of adsorbed benzene at the discharge stage. Five ‘storage–discharge’ cycles were examined, which suggests that Ag/HZSM-5 catalysts are very stable during the cycled ‘storage–discharge’ (CSD) plasma catalytic process. High oxidation rate of absorbed benzene as well as low energy cost can be achieved at a moderate discharge power. In an example of the CSD plasma catalytic remedy of simulated air containing 4.7 ppm benzene with 50% RH and 600 ml min−1 flow rate, the energy cost was as low as 3.7 × 10−3 kWh m−3 air. This extremely low energy cost to remove low-concentration pollutants from air undoubtedly makes the environmental applications of the plasma catalytic technique practical.

We report the formation of wave-like structures and nanostructured fuzzes in the polycrystalline tungsten (W) irradiated with high-flux and low-energy helium (He) ions. From conductive atomic force microscope measurements, we have simultaneously obtained the surface topography and current emission images of the irradiated W materials. Our measurements show that He-enriched and nanostructured strips are formed in W crystal grains when they are exposed to low-energy and high-flux He ions at a temperature of 1400 K. The experimental measurements are confirmed by theoretical calculations, where He atoms in W crystal grains are found to cluster in a close-packed arrangement between {101} planes and form He-enriched strips. The formations of wave-like structures and nanostructured fuzzes on the W surface can be attributed to the surface sputtering and swelling of He-enriched strips, respectively.

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He-induced W nanofuzz growth over the W divertor target is one of the main limiting factors affecting the current design and development of fusion reactors. In this paper, based on He reaction rate model in W, we simulate the growth and evolution of He nanobubbles during W nanofuzz formation under fusion-relevant He+ irradiation conditions. Our modeling unveils the existence of He nanobubble-enriched W surface layer (<10 nm), formed due to the He diffusion in W crystal into defect sites. At an elevated temperature, the growth of He bubbles in the W surface layer prevents He atoms diffusing into the deep layer (>10 nm). The formation of W nanofuzz at the surface is attributed to surface bursting of high-density He bubbles with their radius of ~4 nm, and an increase in the surface area of irradiated W. Our findings have been well confirmed by the experimental measurements.

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