Thermochromic Energy Efficient Windows: Fundamentals, Recent Advances, and Perspectives.

Thermochromic energy efficient windows represent an important protocol technology for advanced architectural windows with energy-saving capabilities through the intelligent regulation of indoor solar irradiation and the modulation of window optical properties in response to real-time temperature stimuli. In this review, recent progress in some promising thermochromic systems is summarized from the aspects of structures, the micro-/mesoscale regulation of thermochromic properties, and integration with other emerging energy techniques. Furthermore, the challenges and opportunities in thermochromic energy-efficient windows are outlined to promote future scientific investigations and practical applications in building energy conservation.

Bioavailability and health risk of toxic heavy metals (As, Hg, Pb and Cd) in urban soils: A Monte Carlo simulation approach.

Toxic heavy metals pollution in urban soil has become a major global issue due to its adverse effects on the environment and human health. In this paper, 26 soil samples were analyzed to assess the speciation, bioavailability and human health risk of Arsenic (As), Mercury (Hg), Lead (Pb) and Cadmium (Cd) in urban soils of a heavy industrial city in NE China by using a Monte Carlo simulation approach. The results showed that As, Hg, Pb and Cd concentrations in the soil all exceed the corresponding background value of study area. Mercury displays the highest value of geo-accumulation index (Igeo), followed by Cd, Pb and As. The pollution load index (PLI) value (>2) indicates a moderate pollution level in the study area. The chemical speciation of HMs mainly exists in residual fraction except Cd. The probabilistic health risk assessment demonstrated that the mean values of Total Carcinogenic Risk (TCR) and Hazard Index (HI) calculated with total concentration are at the unacceptable level, with a higher risk to children than adults. However, the mean values calculated with bioavailable fraction are all within the acceptable level. The mean value of TCR and HI obtained by bioavailable fraction is about 96% and 95% lower than that obtained by total concentration, respectively. Thus, this study suggested that the bioavailable fraction of HMs is a more reliable parameter for health risk assessment, while the total concentration of HMs can overestimate the true risk. The results of this study provide some insight into the speciation, bioavailability and health risks of toxic heavy metals in urban soils in those heavy industrial cities.

Genetic interpretation and health risk assessment of arsenic in Hetao Plain of inner Mongolia, China.

Arsenic is a toxic element widely spread in soils and groundwater that can cause a great hazard to ecology and human health. In this paper, 51 groundwater and 12 sediment samples were analyzed to investigate the sources and evolution mechanism of arsenic and identify the hydrochemical characteristics of groundwater in Hetao Plain, Inner Mongolia through Kriging interpolation, Piper trilinear diagram and ion correlation analysis. Results show that high arsenic groundwater is mainly distributed in the areas with reducing environment. Arsenic has a strong positive correlation with bicarbonic acid and a negative correlation with nitric acid. Arsenic in the sediment is easily adsorbed by iron-manganese compounds. In a reducing environment, arsenic is however released while iron-manganese oxides are reduced. Through triangular fuzzy numbers, a health risk assessment was conducted to evaluate the hazard caused by high arsenic groundwater to humans. Results suggest that the highest carcinogenic risk values of arsenic for children, men, and women are 3.9 × 10-3, 2.38 × 10-3, and 2.35 × 10-3, respectively that greatly exceeds the acceptable risk value. The findings of this paper provide useful insight into the occurrence mechanism of arsenic in those areas with high arsenic groundwater and the potential health risk to humans.

Transparent Wood Composites Fabricated by Impregnation of Epoxy Resin and W-Doped VO2 Nanoparticles for Application in Energy-Saving Windows.

Two types of transparent wood composites with anisotropic structure for energy-saving windows were successfully fabricated by infiltration of epoxy resin dispersion containing tungsten-doped vanadium dioxide nanoparticles (W-doped VO2 NPs) into the delignified wood template and subsequent polymerization. The well integration of the epoxy resin, W-doped VO2 NPs, and the pore-structured wood endowed the anisotropic composites with high visible transmittance (68.2% for the composite prepared from longitudinally cut trees (L-composite), 73.3% for the composite prepared from radically cut trees (R-composite)), obviously different mechanical performance (fracture stress of 74.57 MPa (L-composite) and 56.14 MPa (R-composite) and modulus of 1.47 GPa (L-composite) and 1.23 GPa (R-composite)), and low thermal conductivity (0.20 W·m-1 K-1 (L-composite) and 0.32 W·m-1 K-1 (R-composite)). Moreover, these two kinds of W/VO2 transparent wood composites both show an outstanding thermoregulation ability when they are used as windows. A significant amount of heat (from a simulated light source) was reflected by VO2 NPs, and as a result, the indoor temperature of a demo system had a significant slower temperature increase rate when compared with that for a similar system with a common glass panel applied. Novel transparent wood composites combining a low thermal conductivity wood template and thermochromic VO2 NPs provide a potential solution for replacement of heavy, high thermal conductivity, and infrared transparent glass but still meet indoor occupancy view perception.

Methanol distribution and electroosmotic drag in hydrated poly(perfluorosulfonic) acid membrane.

The methanol distribution and electroosmotic drag in hydrated poly(perfluorosulfonic) acid electrolyte membrane are studied using molecular dynamics simulations under various electric fields applied. The results indicate that the methanol molecules are preferentially distributed near the hydrophobic PFSA backbones with their methyl groups in contact with the fluorine atoms and their hydroxyl groups pointing to the hydrophilic subphase. As the hydroxyl groups of methanol forming hydrogen bonds, hydroxyl groups are more likely to accept hydrogen atoms than to donate hydrogen atoms. The calculated methanol diffusion coefficient is in good correspondence with experimental values, and the electroosmotic drag coefficient for methanol is much smaller than that of water molecules.