Which forcing factors fit? Using ecosystem models to investigate the relative influence of fishing and changes in primary productivity on the dynamics of marine ecosystems

Fishing mortality and primary production (or proxy for) were used to drive the dynamics of fish assemblages in 9 trophodynamic models of contrasting marine ecosystems. Historical trends in abundance were reconstructed by fitting model predictions to observations from stock assessments and fisheries independent survey data. The model fitting exercise derives values for otherwise unknown parameters that specify the relative strength of trophic interactions and, in some instances, a time series anomaly for changes in primary production. We measured how much better or worse were model predictions when bottom-up forcing by primary production were added to top-down forcing by fishing. Searching for cross system patterns, the relative contribution of fishing and changes in primary production, mediated through trophic interactions, are evaluated for the ecosystems as a whole and for selected similar species in different ecosystems. The analysis provides a simple qualitative way to explain which forcing factors have most influence on modeled dynamics. Both fishing and primary production forcing were required to obtain the best model fits to data. Fishing effects more strongly influenced 6 of 9 of the ecosystems, but primary production was more often found to be the main factor influencing the selected pelagic and demersal fish stock trends. Examination of sensitivity to ecological and model parameters suggests that the results are the product of complex food-web interactions rather than simple deterministic responses of the models.     

Effects of arsenic on nitrate metabolism in arsenic hyperaccumulating and non-hyperaccumulating ferns

This study investigated the effects of arsenic on the in vitro activities of the enzymes (nitrate reductase and nitrite reductase) involved in nitrate metabolism in the roots, rhizomes, and fronds of four-month old Pteris vittata (arsenic – hyperaccumulator) and Pteris ensiformis (non-arsenic--hyperaccumulator) plants. The arsenic treatments (0, 150, and 300 μM as sodium arsenate) in hydroponics had adverse effects on the root and frond dry weights, and this effect was more evident in P. ensiformis than in P. vittata. Nitrate reductase and nitrite reductase activities of arsenate-treated plants were reduced more in P. ensiformis than in P. vittata. This effect was accompanied by similar decreases in tissue NO₃^? concentrations. Therefore, this decrease is interpreted as being indirect, i.e., the consequence of the reduced NO₃^? uptake and translocation in the plants. The study shows the difference in the tolerance level of the two Pteris species with varying sensitivity to arsenic.     

Improving enterprise competitive advantage with industrial symbiosis: case study of a smeltery in China

Industrial symbiosis, a subfield of industrial ecology, focuses on transforming the waste of one firm into the valuable input of another, which improves the competitive advantages of supply chain by reducing production cost and improving environmental performance. Considering the specific situation where there are so many state-owned big company groups in China, this paper utilizes the ideas of constructing an industrial symbiosis among different firms, and does a case study on applying the concept into the inner relationships' reconstruction among different production systems in a big state-owned smeltery in South-west China. Three kinds of approaches are explored: 1) recycling and reusing the release; 2) concentrating and abstracting metals from the residues; 3) extending the product chain for value-added products. The results show that it can effectively improve the competitive advantage of the enterprise in terms of decreasing production cost and improving environmental performance.     

炼钢厂1号—3号转炉煤气回收实践

针对提钒炼钢厂建设于20世纪70年代初的1号—3号转炉实施煤气回收的可能性进行了论证,对影响煤气回收的问题提出了相应的完善措施,在此基础上成功实施了1号—3号转炉煤气回收改造,改进后年回收转炉煤气达2 127 138GJ以上,可发电59 124 kW.h,减少CO2排放量近20万t,对降低生产能耗及减少温室气体排放起到了较好作用。     

基于正交试验的谷物粉尘燃烧特性影响因素研究

为了研究谷物粉尘燃烧特性影响因素，以可食用玉米淀粉为研究对象，通过ZY6243锥形量热仪（CONE）进行了单因素和正交试验，研究了粉尘粒径、惰性介质CaCO3质量分数、热辐射通量对玉米淀粉燃烧特性的影响效应。应用直观分析法和方差分析法定性地研究了各因素对玉米淀粉热释放速率峰值的影响程度并进行了排序，2种方法得出的结论基本一致。研究结果表明:各因素对玉米淀粉热释放速率峰值的影响程度依次为:CaCO3质量分数＞粉尘粒径＞热辐射通量；其中惰性介质CaCO3对热释放速率峰值和引燃时间的影响最为显著。     

A novel model based on CEEMDAN,IWOA, and LSTM for ultra-short-term wind power forecasting

Environmental Science and Pollution Research - The randomness and instability of wind power bring challenges to power grid dispatching. Accurate prediction of wind power is significant to ensure...     

High efficiency chlorine removal from polyvinyl chloride (PVC) pyrolysis with a gas–liquid fluidized bed reactor

In this research a gas–liquid fluidized bed reactor was developed for removing chlorine (Cl) from polyvinyl chloride (PVC) to favor its pyrolysis treatment. In order to efficiently remove Cl within a limited time before extensive generation of hydrocarbon products, the gas–liquid fluidized bed reactor was running at 280–320 °C, where hot N₂ was used as fluidizing gas to fluidize the molten polymer, letting the molten polymer contact well with N₂ to release Cl in form of HCl. Experimental results showed that dechlorination efficiency is mainly temperature dependent and 300 °C is a proper reaction temperature for efficient dechlorination within a limited time duration and for prevention of extensive pyrolysis; under this temperature 99.5% of Cl removal efficiency can be obtained within reaction time around 1 min after melting is completed as the flow rate of N₂ gas was set around 0.47–0.85 Nm³ kg^?1 for the molten PVC. Larger N₂ flow rate and additives in PVC would enhance HCl release but did not change the final dechlorination efficiency; and excessive N₂ flow rate should be avoided for prevention of polymer entrainment. HCl is emitted from PVC granules or scraps at the mean time they started to melt and the melting stage should be taken into consideration when design the gas–liquid fluidized bed reactor for dechlorination.     

Study on microstructure and extinction characteristics of particulate matter in diesel engine fueled with different biodiesels

Environmental Science and Pollution Research - Biodiesel combustion particulate matter (PM) is different from diesel combustion PM in terms of microscopic morphology, which directly affects the...