Photochemical roles of rapid economic growth and potential abatement strategies on tropospheric ozone over South and East Asia in 2030

A regional air quality simulation framework including the Weather Research and Forecasting modeling system (WRF), the Community Multi-scale Air Quality modeling system (CMAQ), and precursor emissions to simulate tropospheric ozone over South and East Asia is introduced. Concentrations of tropospheric ozone and related species simulated by the framework are validated by comparing with observation data of surface monitoring, ozonesondes, and satellites obtained in 2010. The simulation demonstrates acceptable performance on tropospheric ozone over South and East Asia at regional scale. Future energy consumption, carbon dioxide (CO2), nitrogen oxides (NOx), and volatile organic compound (VOC) emissions in 2030 under three future scenarios are estimated. One of the scenarios assumes a business-as-usual (BAU) pathway, and other two scenarios consider implemenation of additional energy and environmental strategies to reduce energy consumption, CO2, NOx, and VOC emissions in China and India. Future surface ozone under these three scenarios is predicted by the simulation. The simulation indicates future surface ozone significantly increases around India for a whole year and around northeastern China in summer. NOx is a main driver on significant seasonal increase of surface ozone, whereas VOC as well as increasing background ozone and methane is also an important factor on annual average of surface ozone in East Asia. Warmer weather around India is also preferable for significant increase of surfac ozone. Additional energy and environmental strategies assumed in future scenarios are expected to be effective to reduce future surface ozone over South and East Asia

Stochastic flutter analysis of a three-degree-of-freedom airfoil under vertical turbulence disturbance

This paper investigates the nonlinear stochastic dynamic response of a three-degree-of-freedom(3-DOF) airfoil with high substructural nonlinearity under vertical turbulent disturbances. Considering a two-dimensional flow field, the Dryden turbulence model is used to describe the vertical turbulent disturbance, and a nonlinear stochastic aerodynamic model based on the Theodorsen theory is established for the stochastic flutter problem of the wing. An analysis is conducted to reduce the dimensionality of the airfoil system and solve the critical flutter velocity of the system. The Monte-Carlo method is applied to analyze the stochastic P-bifurcation problem of the system, and the effects of parameters such as the incoming velocity, turbulence scale and intensity on the stochastic dynamics behavior of the system are clarified. It is shown that the amplitude of the steady-state oscillation of the system increases with the incoming velocity and turbulence intensity, whereas the critical flutter speed decreases with increases in these parameters

The effect of dual substitution of Na and Al on ionic conductivity of Na0.5Bi0.5TiO3 ceramics

The Na and Al dual substitution Na0.5Bi0.5TiO3 samples were synthesized by the conventional solid-state reaction method. The oxygen ion conductivity and migration in the Na0.54Bi0.46Ti1−xAlxO2.96−x/2 (x = 0.02, 0.04, 0.06 and 0.08) samples were investigated. The grain conductivity and relaxation activation energy of the Na0.54Bi0.46Ti1−xAlxO2.96−x/2 samples show the trend of declining-rising-declining with the increase of Al-doped content. The highest grain conductivity can arrive at 0.0016 S/cm for the Na0.54Bi0.46Ti1−xAlxO2.96−x/2 (x = 0.06) sample at 673 K and the corresponding activation energy is about 0.80 eV, which are the lowest results of oxygen ion diffusion in the Na0.54Bi0.46Ti1−xAlxO2.96−x/2 (x = 0.02, 0.04, 0.06 and 0.08) samples. The mobile oxygen vacancy content decreases with increasing Al-doping content in the Na0.54Bi0.46Ti1−xAlxO2.96−x/2 compounds. The sudden change of grain conductivity in NBT-Na4Al6 sample may be from the lower activation energy and better oxygen vacancy mobility. These results are helpful to improve the electrical performance by doping methods. Keywords: Oxide ionic conductivity, Dielectric relaxation, Oxygen vacancy mobility, Dual substitutio

Preparation of Fe-substituted hexaaluminate and its catalytic performance for methane combustion

Fe-substituted hexaaluminate (BaFexAl12-xO19-delta) was prepared with co-precipitation method followed by hydrothermal treatment. The XRD and SEM results indicated that no hexaaluminate phase was formed when calcined below 1000 degreesC, and hexaaluminate was the dominant phase when calcined above 1100 degreesC. Moreover, the UV-Vis-DR result verified that Fe occupied the Oh sites in Fe-hexaaluminate structure. With the increase of Fe content (xless than or equal to3), the activity of hexaaluminate for methane combustion was raised. The most active catalyst was BaFe3Al9O19-delta, the light-off temperature of which was 515 degreesC. Compared with BaFeAl11O19-delta, the high-temperature activity of Ba0.5La0.5FeAl11O19-delta increased greatly, no obvious promotion for methane ignition activity was observed. The reactant atmosphere had impact on methane ignition activity, but slight influence on high-temperature activity due to the transport limitation. Stability experiment was carried out at 800 degreesC for 100 h, and no deactivation was detected

Effects of fully open-air CO2 elevation on leaf ultrastructure, photosynthesis and yield of two soybean cultivars.

The objective of this study was to investigate the effect of elevated (550 ± 17 μmol mol−1) CO2 concentration ([CO2]) on leaf ultrastructure, leaf photosynthesis and seed yield of two soybean cultivars [Glycine max (L.) Merr. cv. Zhonghuang 13 and cv. Zhonghuang 35] at the Free-Air Carbon dioxide Enrichment (FACE) experimental facility in North China. Photosynthetic acclimation occurred in soybean plants exposed to long-term elevated [CO2] and varied with cultivars and developmental stages. Photosynthetic acclimation occurred at the beginning bloom (R1) stage for both cultivars, but at the beginning seed (R5) stage only for Zhonghuang 13. No photosynthetic acclimation occurred at the beginning pod (R3) stage for either cultivar. Elevated [CO2] increased the number and size of starch grains in chloroplasts of the two cultivars. Soybean leaf senescence was accelerated under elevated [CO2], determined by unclear chloroplast membrane and blurred grana layer at the beginning bloom (R1) stage. The different photosynthesis response to elevated [CO2] between cultivars at the beginning seed (R5) contributed to the yield difference under elevated [CO2]. Elevated [CO2] significantly increased the yield of Zhonghuang 35 by 26% with the increased pod number of 31%, but not for Zhonghuang 13 without changes of pod number. We conclude that the occurrence of photosynthetic acclimation at the beginning seed (R5) stage for Zhonghuang 13 restricted the development of extra C sink under elevated [CO2], thereby limiting the response to elevated [CO2] for the seed yield of this cultivar