Search

Geothermal pavements can be used with ground-source heat pump systems to sustainably provide energy for heating and cooling by incorporating ground heat exchanger elements underneath pavement surfaces. This work investigates the suitability of geothermal pavements at scale, adopting the city of Cardiff, UK, as a case-study. A two-scale modelling framework, combining detailed small-scale with holistic large-scale approaches, is presented, incorporating the accuracy of the former with the continuity of the latter. The results show that between 184 kWh and 345 kWh of thermal energy per metre length of pavement can be supplied annually, depending on soil profile. Moreover, geothermal operation can reduce anthropogenic heat flux into the ground from heated basements, and its associated negative impacts, by about 390 MWh/year. A city-scale analysis using population-consistent geographic areas called LSOAs, estimates that geothermal pavements can supply about 23% of the entire city residential heat demand, or up to 75% with heat sharing between LSOAs. The suitability of geothermal pavements for larger LSOAs is highlighted, supplying up to 100% of the annual domestic heat demand. Investigating the carbon emissions of heating and cooling technologies shows potential reductions of up to 75% when replacing gas boilers and resistance heating with geothermal pavement systems. • Two-scale modelling is used to assess city-scale geothermal pavement potential. • Depending on ground conditions, 184–345 kWh annually/m road of heat can be provided. • Geothermal pavements can reduce anthropogenic heat flux into the ground by ∼ 390 MWh/a. • In low population density areas 100% residential demand can be fulfilled, overall 23%. • Replacing traditional systems can reduce carbon emission by ∼ 75%. [ABSTRACT FROM AUTHOR]

• Long-term exposure to PM 2.5 are associated with large- and small- airway function. • Organic matter and nitrate show stronger associations with lung function than PM 2.5. • Exposure to PM 2.5 constituents might be more important in impairing lung function. The associations of long-term exposure to various constituents of fine particulate matter (≤2.5 μm in aerodynamic diameter, PM 2.5) air pollution with lung function were not clearly elucidated in developing countries. The aim was to evaluate the associations of long-term exposure to main constituents of PM 2.5 with lung function in China. This is a nationwide, cross-sectional analysis among 50,991 study participants from the China Pulmonary Health study. Multivariable linear regression models were used to obtain differences of forced expiratory volume in 1 s (FEV 1), forced vital capacity (FVC), FEV 1 /FVC, peak expiratory flow (PEF), and forced expiratory flow at 25–75% of exhaled FVC (FEF 25-75%) associated with an interquartile range (IQR) change of PM 2.5 or its constituents. Residential annual PM 2.5 levels varied from 26 μg/m3 to 92 μg/m3 (average: 53 μg/m3). An IQR increase of PM 2.5 concentrations was associated with lower FEV 1 (19.82 mL, 95% CI: 11.30–28.33), FVC (17.45 mL, 95% CI: 7.16–27.74), PEF (86.64 mL/s, 95% CI: 59.77–113.52), and FEF 25-75% (31.93 mL/s, 95% CI: 16.64–47.22). Black carbon, organic matter, ammonium, sulfate, and nitrate were negatively associated with most lung function indicators, with organic matter and nitrate showing consistently larger magnitude of associations than PM 2.5 mass. This large-scale study provides first-hand epidemiological evidence that long-term exposure to ambient PM 2.5 and some constituents, especially organic matter and nitrate, were associated with lower large- and small- airway function. [ABSTRACT FROM AUTHOR]

Herein, we proposed a new strategy to enhance compatibility and flame retardancy of the immiscible and flammable polylactic acid (PLLA)/polypropylene (PP) blend materials simultaneously. It is found that the boehmite nanorods are located at the PLLA-PP interface by in-situ reactions and the compatibility between phases is greatly improved, resulting in significant enhancement of mechanical properties and flame retardancy: tensile strength and elongation at break of the blends with 7 wt% reactive nanorods are 163% and 601% higher than that without nanorods, respectively. Meanwhile, the peak heat release rate (PHRR) decreases 51.4% and limiting oxygen index (LOI) increases 22.6%. The synergetic improvements are directly attributed to the strengthened interface and the interface takes the role of the flame retarding belt. The research opens a new avenue to fabricate non-halogen flame retardant multicomponent polymer materials with simultaneously enhanced mechanical properties. [Display omitted] •Ternary Poly(L-lactic acid)/Polypropylene/boehmite nanorods nanocomposites were prepared. •Epoxide groups modified boehmite nanorods are thermodynamically located at the PLLA/PP blend interface by the in-situ reactions. •The interfacially located nanorods improve the mechanical properties and flame retardancy of the PLLA/PP blends simultaneously. [ABSTRACT FROM AUTHOR]