A fractal derivative model to quantify bed-load transport along a heterogeneous sand bed

Environmental Fluid Mechanics - Bed-load transport is a complex process exhibiting anomalous dynamics, which cannot be efficiently described using the traditional advection–diffusion...     

Photosynthesis and related metabolic mechanism of promoted rice (Oryza sativa L.) growth by TiO2 nanoparticles

• The rice growth was promoted by nano-TiO₂ of 0.1–100 mg/L. • Nano-TiO₂ enhanced the energy storage in photosynthesis. • Nano-TiO₂ reduced energy consumption in carbohydrate metabolism and TCA cycle. Titanium dioxide nanoparticle (nano-TiO₂), as an excellent UV absorbent and photo-catalyst, has been widely applied in modern industry, thus inevitably discharged into environment. We proposed that nano-TiO₂ in soil can promote crop yield through photosynthetic and metabolic disturbance, therefore, we investigated the effects of nano-TiO₂ exposure on related physiologic-biochemical properties of rice (Oryza sativa L.). Results showed that rice biomass was increased >30% at every applied dosage (0.1–100 mg/L) of nano-TiO₂. The actual photosynthetic rate (Y(II)) significantly increased by 10.0% and 17.2% in the treatments of 10 and 100 mg/L respectively, indicating an increased energy production from photosynthesis. Besides, non-photochemical quenching (Y(NPQ)) significantly decreased by 19.8%–26.0% of the control in all treatments respectively, representing a decline in heat dissipation. Detailed metabolism fingerprinting further revealed that a fortified transformation of monosaccharides (D-fructose, D-galactose, and D-talose) to disaccharides (D-cellobiose, and D-lactose) was accompanied with a weakened citric acid cycle, confirming the decrease of energy consumption in metabolism. All these results elucidated that nano-TiO₂ promoted rice growth through the upregulation of energy storage in photosynthesis and the downregulation of energy consumption in metabolism. This study provides a mechanistic understanding of the stress-response hormesis of rice after exposure to nano-TiO₂, and provides worthy information on the potential application and risk of nanomaterials in agricultural production.     

Does regional energy consumption disparities assist to control environmental degradation in OBOR: an entropy approach

China launched the One Belt & One Road (OBOR) initiative to minimize the energy resource shortage. The China’s nearby countries are rich in energy resources especially Middle East and North Africa (MENA) and Asian countries which make them ideal locations to cooperate with China in terms of energy resources, as 42.8% of world energy consumption belongs to OBOR countries. The present study elaborates the spatial distribution pattern of energy consumption disparities and its impact on environment. To do this, an entropy approach is utilized to compute the energy consumption inequalities in OBOR and its regions. The spatial and Pareto analysis show that MENA, East, and Southeast Asian economies have the highest degree of energy consumption inequalities, while European and Central Asian economies show the lowest energy consumption inequalities in OBOR region. The long-run estimates indicate that energy consumption inequalities enhance the CO₂ emission in OBOR and its region except South and Southeast Asia. Financial development also has a significantly positive impact on CO₂ emission in all models for OBOR and its regions except East Asia. Based on findings, the spatial distribution analysis is applicable to maintain balance in regional energy consumption inequality within OBOR and its regions.

     

Changes Of Hydrological Environment And Their Influences On Coastal Wetlands InThe Southern Laizhou Bay, China

The structure and function of the coastal wetland ecosystem in the southern Laizhou Bay have been changed greatly and influenced by regional hydrological changes. The coastal wetlands have degraded significantly during the latest 30 years due to successive drought, decreasing of runoff, pollution, underground saline water intrusion, and aggravating marine disasters such as storm tides and sea level rising. Most archaic lakes have vanished, while artificial wetlands have been extending since natural coastal wetlands replaced by salt areas and ponds of shrimps and crabs. The pollution of sediments in inter-tidal wetlands and the pollution of water quality in sub-tidal wetlands are getting worse and therefore “red tides” happen more often than before. The biodiversity in the study area has been decreased. Further studies are still needed to protect the degraded coastal wetlands in the area.     

Depth perception,dark adaptation,vigilance and accident proneness of Chinese coal mine workers

To explore the relationships between human factors and accident proneness of coal mine workers, the depth perception, dark adaptation and vigilance abilities of 239 Chinese coal mine workers were tested and their accident proneness was surveyed with an accident proneness questionnaire. The results indicated that dark adaptation and vigilance abilities of the mine workers declined with increasing age. Vigilance had a significant negative relationship with accident proneness. There were significant differences in vigilance between coal mine workers doing different types of work. Individual difference in vigilance was relevant to the type of work that an individual did in a coal mine. The dark adaptation index had a significant positive relationship with accident proneness. Coal mine workers with weaker dark adaptation ability were also more accident prone. Some ergonomics recommendations concerning coal mine safety management in China are proposed.     

O3/BAF工艺系统中有机物生物降解数学模型

研究臭氧预氧化/曝气生物滤池（O₃/BAF）联合工艺深度处理实际城市污水二级出水过程中,后续BAF系统中有机物的生物降解数学模型。以有机底物浓度、填料层高度两个基本变量为控制条件,研究BAF的总体运行常数和填料特性常数,得出BAF有机物生物降解动力学方程为S_e/S₀=exp(－Kh/qSⁿ₀)。出水与进水COD浓度比值（S_e/S₀）的对数与反应器填料高度（h）之间可表达成一次函数关系。在不同的进水浓度（S₀）下,根据ln（S_e/S₀）~h和关系式m=K/qSⁿ₀,得到方程ln(q_m)=－nln(S₀)+lnK。BAF总体运行常数K和填料特性常数n分别为1.708和0.5063。该模型对BAF工艺有如下指导意义：可以根据设计流量、进水有机物浓度和出水浓度,初步确定BAF的尺寸（如横截面积、高度等）。     

不同碳源和泥龄对反硝化聚磷的影响

在4个SBR装置(1#~4#)中,对4种不同比例的丙酸/乙酸合成废水采用厌氧/缺氧方式驯化富集反硝化聚磷菌(DPB),研究了碳源浓度和污泥龄对除磷的影响。实验结果表明:(1)厌氧段碳源COD浓度越高,释磷越充分,溶解性正磷酸盐(SOP)去除率越高;但当碳源COD浓度超过某个浓度值时,未反应完全的有机物残留于后续缺氧段对缺氧吸磷产生抑制作用。(2)污泥龄SRT=15 d时,活性污泥的性能较好,达到了较好的除磷效果。(3)在相同碳源浓度和相同的污泥龄下,随着丙酸/乙酸比例的提高,SOP的去除率逐渐的降低。说明在厌氧/缺氧环境下,碳源中丙酸比例的提高不利于系统中磷的去除。高乙酸含量的碳源更适合反硝化除磷系统。     

TiO_2光催化对微滤去除腐殖酸的膜污染控制研究

着重研究了不同紫外灯光源和照射时间条件下,TiO_2光催化(PCO)对微滤去除腐殖酸过程中的膜污染控制,并探讨了膜污染的控制机理。研究结果表明,TiO_2光催化能有效提高微滤对腐殖酸的去除,同时降低膜通量的下降,起到有效控制膜污染的作用。进一步的实验分析表明,TiO_2光催化控制膜污染的主要机理在于将腐殖酸降解为易于被TiO_2吸附的小分子量物质,吸附腐殖酸降解产物后的TiO_2聚合颗粒粒径增大,易于在膜表面形成更为松散的沉积层,并使膜污染从以膜孔堵塞和沉积层污染为主转化为以沉积层污染为主的可逆性污染。     

新型活性炭固定化产品的制备及其处理焦化废水的特性

为解决优势菌种工程应用,研究不同固定化方法、载体和结构的固定化产品对焦化废水的降解特性。用活性炭粉末吸附菌种后,与聚乙烯醇和海藻酸钠混合制备了新型固定化球;用聚乙烯醇和海藻酸钠包埋吸附菌种的活性炭纤维毡,与立体弹性塑料填料连用,制备出3种不同形状的活性炭纤维膜片固定化产品复合填料。将游离菌和制备的4种活性炭固定化产品投入A/A/O工艺系统平行实验,考察处理焦化废水的效果。结果表明,活性炭纤维膜片固定化产品复合填料对焦化废水的降解能力优于其他固定化产品:缺氧池出水硝酸盐氮和亚硝酸盐氮浓度分别稳定在1.96 mg/L和0.49 mg/L,未产生氮的累积现象,COD去除率可达到60.92%。好氧池COD和氨氮降解效率分别为78.83%和85.52%,苯酚、氰化物降解效率均为97%以上。