ALBERT

Description: A mini liquid-liquid extractor was designed based on a feedback fluidic oscillator. According to the Coanda effect, the designed oscillator with two feedback channels enables good mixing of the aqueous and organic phases. Co-current liquid-liquid extraction was performed in the mini extractor, and it was visually observed that the aqueous phase was dispersed into small droplets because of fluidic oscillation and vortex formation. The aqueous phase was more effectively dispersed at the stage near the outlet and with increasing flow. Several tests were performed for evaluating the extraction performance of the extractor using 30 % tributyl phosphate-kerosene and 3 M HNO 3 solutions as the organic and aqueous phases, respectively. The obtained extraction efficiency was close to the equilibrium efficiency, indicating that this extractor has the potential for liquid-liquid extraction of hazardous liquids. A feedback fluidic mixer based on the Coanda effect is suitable for mixing of two immiscible liquids. Having no moving parts and a short residence time, the mixer can be used in extraction processes of hazardous liquids. The oscillation and low-pressure vortices in the mixer effectively enhance mass transfer between the two immiscible liquids.

Description: Abstract Nitrous oxide (N2O) emissions from soil contribute to global warming and are in turn substantially affected by climate change. However, climate change impacts on N2O production across terrestrial ecosystems remain poorly understood. Here, we synthesised 46 published studies of N2O fluxes and relevant soil functional genes (SFGs, i.e. archaeal amoA, bacterial amoA, nosZ, narG, nirK and nirS) to assess their responses to increased temperature, increased or decreased precipitation amounts, and prolonged drought (no change in total precipitation but increase in precipitation intervals) in terrestrial ecosystem (i.e. grasslands, forests, shrublands, tundra and croplands). Across the dataset, temperature increased N2O emissions by 33%. However, the effects were highly variable across biomes, with strongest temperature responses in shrublands, variable responses in forests and negative responses in tundra. The warming methods employed also influenced the effects of temperature on N2O emissions (most effectively induced by open‐top chambers). Whole‐day or whole‐year warming treatment significantly enhanced N2O emissions, but day‐time, night‐time or short‐season warming did not have significant effects. Regardless of biome, treatment method and season, increased precipitation promoted N2O emission by an average of 55%, while decreased precipitation suppressed N2O emission by 31%, predominantly driven by changes in soil moisture. The effect size of precipitation changes on nirS and nosZ showed a U‐shape relationship with soil moisture; further insight into biotic mechanisms underlying N2O emission response to climate change remain limited by data availability, underlying a need for studies that report SFG. Our findings indicate that climate change substantially affects N2O emission and highlight the urgent need to incorporate this strong feedback into most climate models for convincing projection of future climate change.

Description: Requirements for mitigation of the continued increase in greenhouse gas (GHG) emissions are much needed for the North China Plain (NCP). We conducted a meta-analysis of 76 published studies of 24 sites in the NCP to examine the effects of natural conditions and farming practices on GHG emissions in that region. We found that N 2 O was the main component of the area-scaled total GHG balance, and the CH 4 contribution was 〈5%. Precipitation, temperature, soil pH, and texture had no significant impacts on annual GHG emissions, because of limited variation of these factors in the NCP. The N 2 O emissions increased exponentially with mineral fertilizer N application rate, with y  =   0.2389e 0.0058 x for wheat season and y  =   0.365e 0.0071 x for maize season. Emission factors were estimated at 0.37% for wheat and 0.90% for maize at conventional fertilizer N application rates. The agronomic optimal N rates (241 and 185 kg N ha −1 for wheat and maize, respectively) exhibited great potential for reducing N 2 O emissions, by 0.39 (29%) and 1.71 (56%) kg N 2 O-N ha −1  season −1 for the wheat and maize seasons, respectively. Mixed application of organic manure with reduced mineral fertilizer N could reduce annual N 2 O emissions by 16% relative to mineral N application alone while maintaining a high crop yield. Compared with conventional tillage, no-tillage significantly reduced N 2 O emissions by ~30% in the wheat season, whereas it increased those emissions by ~10% in the maize season. This may have resulted from the lower soil temperature in winter and increased soil moisture in summer under no-tillage practice. Straw incorporation significantly increased annual N 2 O emissions, by 26% relative to straw removal. Our analysis indicates that these farming practices could be further tested to mitigate GHG emission and maintain high crop yields in the NCP. A meta-analysis was conducted to examine the effects of natural conditions and farming practices on greenhouse gas emissions in the North China Plain. The results showed that optimized fertilizer N application rate exhibited great potential for reducing N 2 O emissions, by 29% and 56% for the wheat and maize seasons, respectively. Mixed application of organic manure with reduced mineral fertilizer N could reduce annual N 2 O emissions by 16% relative to mineral N application alone while maintaining a high crop yield.