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...     

Association between particulate matter air pollution and cardiovascular disease mortality in Lanzhou,China

Ambient particulate matter (PM) pollution has been linked to elevated mortality, especially from cardiovascular diseases. However, evidence on the effects of particulate matter pollution on cardiovascular mortality is still limited in Lanzhou, China. This research aimed to examine the associations of daily mean concentrations of ambient air pollutants (PM_2.5, PM_C, and PM₁₀) and cardiovascular mortality due to overall and cause-specific diseases in Lanzhou. Data representing daily cardiovascular mortality rates, meteorological factors (daily average temperature, daily average humidity, and atmospheric pressure), and air pollutants (PM_2.5, PM₁₀, SO₂, NO₂) were collected from January 1, 2014, to December 31, 2017, in Lanzhou. A quasi-Poisson regression model combined with a distributed lag non-linear model (DLNM) was used to estimate the associations. Stratified analyses were also performed by different cause-specific diseases, including cerebrovascular disease (CD), ischemic heart disease (IHD), heart rhythm disturbances (HRD), and heart failure (HF). The results showed that elevated concentration of PM_2.5, PM_C, and PM₁₀ had different effects on mortality of different cardiovascular diseases. Only cerebrovascular disease showed a significant positive association with elevated PM_2.5. Positive associations were identified between PM_C and daily mortality rates from total cardiovascular diseases, cerebrovascular diseases, and ischemic heart diseases. Besides, increased concentration of PM₁₀ was correlated with increased death of cerebrovascular diseases and ischemic heart diseases. For cerebrovascular disease, each 10 μg/m³ increase in PM_2.5 at lag4 was associated with increments of 1.22% (95% CI 0.11–2.35%). The largest significant effects for PM_C on cardiovascular diseases and ischemic heart diseases were both observed at lag0, and a 10 μg/m³ increment in concentration of PM_C was associated with 0.47% (95% CI 0.06–0.88%) and 0.85% (95% CI 0.18–1.52%) increases in cardiovascular mortality and ischemic heart diseases. In addition, it exhibited a lag effect on cerebrovascular mortality as well, which was most significant at lag6d, and an increase of 10 μg/m³ in PM_C was associated with a 0.76% (95% CI 0.16–1.37%) increase in cerebrovascular mortality. The estimates of percentage change in daily mortality rates per 10 μg/m³ increase in PM₁₀ were 0.52% (95% CI 0.05–1.02%) for cerebrovascular disease at lag6 and 0.53% (95% CI 0.01–1.05%) for ischemic heart disease at lag0, respectively. Our study suggests that elevated concentration of atmospheric PM (PM_2.5, PM_C, and PM₁₀) in Lanzhou is associated with increased mortality of cardiovascular diseases and that the health effect of elevated concentration of PM_2.5 is more significant than that of PM_C and PM₁₀.

     

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.     

调理料添加比例对菇渣基质发酵效果的影响

为探讨废弃蘑菇基料菇渣改性生产有机栽培基质技术,直接采用菇渣为主要原料,以猪粪作为调理料进行好氧发酵,研究猪粪的不同添加比例对菇渣好氧发酵腐熟条件中的温度、挥发性固体(VS)、p H、全氮、全磷、种子发芽指数(GI)的影响。结果表明,猪粪适宜作为菇渣改性生产有机基质的调理料,发酵过程始终维持含水率在65%左右,3个处理高温持续时间均在5 d以上,满足基质无害化卫生标准要求,发酵完成后p H均符合腐熟基质标准,GI均达到60%以上。而猪粪添加量较少时,可以缩短进入高温发酵期的时间,堆体达到的最高温度较高,堆料腐熟较快,且最有利于氮素的保存和全磷的浓缩。综合以上实验结果表明,在菇渣发酵中添加15%的猪粪有利于改善发酵条件,提高堆体的养分含量。     

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...     

High spatial and seasonal heterogeneity of pCO2 and CO2 emissions in a karst groundwater-stream continuum,southern China

Environmental Science and Pollution Research - Accurate quantification of the emission of CO2 from streams and rivers is one of the primary challenges in determining the global carbon budget...     

Different hydrodynamic processes regulated on water quality (nutrients,dissolved oxygen,and phytoplankton biomass) in three contrasting waters of Hong Kong

The subtropical Hong Kong (HK) waters are located at the eastern side of the Pearl River Estuary. Monthly changes of water quality, including nutrients, dissolved oxygen (DO), and phytoplankton biomass (Chl-a) were routinely investigated in 2003 by the Hong Kong Environmental Protection Department in three contrasting waters of HK with different prevailing hydrodynamic processes. The western, eastern, and southern waters were mainly dominated by nutrient-replete Pearl River discharge, the nutrient-poor coastal/shelf oceanic waters, and mixtures of estuarine and coastal seawater and sewage effluent of Hong Kong, respectively. Acting in response, the water quality in these three contrasting areas showed apparently spatial–temporal variation pattern. Nutrients usually decreased along western waters to eastern waters. In the dry season, the water column was strongly mixed by monsoon winds and tidal currents, which resulted in relatively low Chl-a (<5 μg l^?1) and high bottom DO (>4 mg l^?1), suggesting that mixing enhanced the buffering capacity of eutrophication in HK waters. However, in the wet season, surface Chl-a was generally >10 μg l^?1 in southern waters in summer due to halocline and thermohaline stratification, adequate nutrients, and light availability. Although summer hypoxia (DO <2 mg l^?1) was episodically observed near sewage effluent site and in southern waters induced by vertical stratification, the eutrophication impacts in HK waters were not as severe as expected owing to P limitation and short water residence time in the wet season.     

臭氧/活性炭联合工艺深度处理焦化废水

采用臭氧/活性炭联合工艺对焦化废水A2/O出水进行深度处理。考察了溶液初始pH值、臭氧投加量、活性炭投加量及使用次数、反应时间对焦化废水处理效果的影响。实验结果表明,活性炭的使用可显著提高臭氧对焦化废水COD的去除率,在溶液初始pH值为10.25、臭氧投加量为7.5 mg/min、活性炭投加量50 g/L、反应时间为30 min条件下,COD去除率达到73.51%。同时,在活性炭重复使用10次时,COD去除率为70.85%,仅降低了2.66%。     

重庆市煤炭资源流动及其未来流量估测

从流量和流向两方面，评估探讨了重庆市煤炭资源流动平衡现状及其面临的问题，并根据对重庆市未来5年外省煤炭输入量的预测值，给出相应的建议。结果表明：（1）重庆市煤炭资源产消失衡，自给率逐年下降，需要大量调入外省煤炭弥补其缺口；重庆市煤炭资源流动比率不断上升，煤炭资源流入强度不断加大，对外依赖性不断加强。（2）经济的快速发展导致重庆市煤炭产需失衡，成为其煤炭资源流动持续增强的根本原因，煤炭资源势差是周边煤炭资源流入重庆的主要因素，距离成本、交通成本和价格差影响着重庆市煤炭供应源的具体选择，从而使距离近、交通通达性较好的四川和贵州成为重庆市主要的两个煤炭供应源。（3）在重庆市外部的煤炭产区中，宁夏、陕西、新疆有望成为重庆市煤炭供应的重要来源，加快陕煤南下以及疆煤入川、渝铁路通道建设是保障重庆乃至整个大西南地区能源供应稳定的重大举措。（4）根据未来5年重庆市外省煤炭输入量的预测结果，指出适当提高公路和水路煤炭运能等措施可解决短时期重庆煤炭紧张的问题。此外，发挥长江黄金水道作用和重庆港口优势，加强储煤基地、煤炭中转码头建设，是保障重庆市未来煤炭供应稳定和能源安全的有效举措     

Response of bacterial communities to mining activity in the alpine area of the Tianshan Mountain region,China

Environmental Science and Pollution Research - Anthropogenic activities, such as mining, influence soil bacterial community composition and microbial distributions. In the current study, the...