Removal of imidacloprid and acetamiprid from tea infusions by microfiltration membrane

Removal of imidacloprid and acetamiprid in tea infusions by microfiltration membrane using dead‐end model was investigated in the present study. The results showed that microfiltration significantly promoted the removal of both pesticides (P < 0.05) in tea infusions. Furthermore, the extent of removal was strongly influenced by the pore size of membrane, operational pressure and the concentrations of tea infusions. The initial concentration of imidacloprid and acetamiprid showed no significant effect on their removal rates. The maximum removal rates were 79.7% for imidacloprid and 81.9% acetamiprid. The changes in major chemical components of tea infusions after microfiltration were evaluated. The results indicated that microfiltration caused no considerable changes in total polyphenols and total free amino acids, and small but statistically significant losses (6.3–18.0%) of eight catechins and three methylxanthines when filtration volume reached to 200 mL. The present study validated the application of microfiltration as a potentially feasible and promising method for the removal of imidacloprid and acetamiprid residues from tea infusions.     

Silver-plated polyamide fabrics with high electromagnetic shielding effectiveness performance prepared by in situ reduction of polydopamine and chemical silvering

In this article, the silver-plated polyamide fabrics (SPPAFs) with high electroconductibility and shielding effectiveness were fabricated by using in situ reduction of polydopamine and chemical silvering. The effects of SPPAFs dopamine (C₈H₁₁O₂N) and silver nitrate (AgNO₃) concentration on surface resistivity and electromagnetic interference shielding effectiveness were studied. The results showed that the surface resistivity of SPPAFs can reach a minimum value of 0.06 ± 0.014 Ω cm⁻¹, when C₈H₁₁O₂N concentration is 4 g L⁻¹ and the AgNO₃ concentration is 120 g L⁻¹. The shielding effectiveness of SPPAFs in the wide frequency range of 10–3000 MHz increases with the increase in the concentration of AgNO₃, and increases first and stabilizes afterward with increasing C₈H₁₁O₂N concentration. When the concentration of C₈H₁₁O₂N and AgNO₃ is 3 and 120 g L⁻¹, respectively, mean shielding effectiveness values in the low-, medium-, and high-frequency bands are 71.3, 73.8, and 76.1 dB, respectively. Moreover, the mean shielding effectiveness values is 83.79 dB in the frequency range of 1.2–2.3 GHz. The dominant shielding mechanism of SPPAFs is the reflected electromagnetic waves and the absorption shielding effectiveness is less than 2 dB. The average electromagnetic shielding values of SPPAFs are above 67 dB after 16 weeks of storage, when C₈H₁₁O₂N concentration is 4 g L⁻¹ and the AgNO₃ concentration is 80 and 100 g L⁻¹. The prepared SPPAFs show promising applications in military textiles and smart wearable clothing. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48227.     

溶胀嵌入脂肪酸分子制备高脱硼反渗透膜

采用“溶胀-嵌入-收缩”方法改性聚酰胺反渗透膜，制备了一种高脱硼反渗透膜。通过甲醇溶胀增加了高分子链之间的距离，为疏水性癸酸分子的嵌入提供了场所，然后在压力和浓差极化共同作用下，改性分子选择性嵌入聚酰胺膜的孔内；当甲醇分子离开后，聚酰胺膜收缩将癸酸分子固定在高分子网络中。实验借助溶胀和分子嵌入以及溶胀后的收缩调节聚酰胺膜的孔径大小；利用脂肪酸的疏水性降低聚酰胺膜的极性，从而实现增加空间位阻和减少氢键结合位点数量的目的。实验结果显示，改性膜的脱硼率和截盐率均明显升高，截盐率从90.36%增加到96.46%，脱硼率从未改性膜的47.85%增加到77.32%，渗透液的硼含量达到WTO的使用标准。虽然水和硼的渗透性均下降，但是水和硼的渗透选择性增加，证明该方法有利于提高水硼选择性。     

液压支架快速撤除技术研究应用

新汶矿业集团经过探索和实践,研究运用了差异互补式全掩护支护技术、掩护支架自牵引联动装置工艺、矿车运输、滑移运输多用轨道、自动找正装车平台、液控调整装置等新技术、新工艺,做到了液压支架综合流程快速回撤,实现了高效化、连贯化安全回撤,取得了良好的经济效益。     

Al2O3/Yttria‐Stabilized Zirconia Hollow‐Fiber Membrane Incorporated with Iron Oxide for Pb(II) Removal

Removal by absorptive ceramic membranes can simultaneously absorb and separate metal ions from water. Alumina/yttria‐stabilized zirconia (Al₂O₃/YSZ) hollow‐fiber membranes, fabricated using phase inversion and sintering process, were deposited with iron oxide by an in‐situ hydrothermal process. The results showed that α‐Fe₂O₃ was produced and incorporated across the membranes. A reduction in flux was recorded with the deposition of α‐Fe₂O_3. However, it improved the adsorption capacity for heavy metal adsorption. The adsorption‐separation test demonstrated that the optimized membrane is able to completely remove Pb(II) ions after two hours.     

Kernel-based fourth-order diffusion for image noise removal

The fourth-order partial differential equations have good performance on noise smoothing and edge preservation without creating blocky effects on smooth regions. However, for low signal-to-noise ratio images, the discrimination between edges and noise is a challenging problem. A novel kernel-based fourth-order diffusion is proposed in this paper. It introduces a kernelized gradient operator in the fourth-order diffusion process, which leads to more effective noise removal capability. Experiment results show that this method outperforms several previous anisotropic diffusion methods for noise removal and edge preservation.     

Efficiency and effectiveness enhancement of an intercooler of two‐stage air compressor by low‐cost Al2O3/water nanofluids

The present study was aimed to utilize low‐cost alumina (Al₂O₃) nanoparticles for improving the heat transfer behavior in an intercooler of two‐stage air compressor. Experimental investigation was carried out with three different volume concentrations of 0.5%, 0.75%, and 1.0% Al₂O₃/water nanofluids to assess the performance of the intercooler, that is, counterflow heat exchanger at different loads. Thermal properties such as thermal conductivity and overall heat transfer coefficient of nanofluid increased substantially with increasing concentration of Al₂O₃ nanoparticles. Specific heat capacity of nanofluids were lower than base water. The intercooler performance parameters such as effectiveness and efficiency improved appreciably with the employment of nanofluid. The efficiency increased by about 6.1% with maximum concentration of nanofluid, that is, 1% at 3‐bar compressor load. It is concluded from the study that high concentration of Al₂O₃ nanoparticles dispersion in water would offer better heat transfer performance of the intercooler.     

双河油田注入水适应性及注水井酸化解堵研究

考察了双河油田双河联、江河联注入水堵塞地层的因素;膨胀性黏土，悬浮固体颗粒。细菌及悬浮污油。含膨胀性黏土的双河南、双河北及不含膨胀性黏土的双江岩心粉，在注入水中相对于地层水中的体积膨胀度分别为14．5％、11．1％及0．02％；注入100PV不含悬浮颗粒的等体积比地层水、注入水混合水使双河、双江岩心渗透率分别下降7％和4％、9％和7％。注入水中悬浮颗粒引起岩心渗透率下降，粒径越大、颗粒浓度越大、注入量越大，则渗透率越低。在粒径2．1μm或颗粒浓度3mg／L前后下降幅度变化较大。注入水中硫酸盐还原菌引起岩心渗透率下降，含菌量越大则渗透率开始下降时的注水量越小，注入含菌50个／L的水100PV使岩心渗透率下降7％。岩心对注水合油量敏感，注入含油量20mg／L的水50PV使岩心渗透率下降20％。在岩心注水实验中渗透率下降最严重的是双河南岩心，其次是双河北岩心．江河岩心较轻，注入精细过滤水的双河北岩心渗透率下降大大减少．说明悬浮固体是造成注水堵塞的主要因素。为了解除双河油田注水井的堵塞，研制了含黏土稳定剂、缓蚀剂、铁离子稳定剂、互溶剂的土酸液，与南阳油田使用的低伤害酸液一起，用于1口注水井的解堵，效果良好。图7表4参5。     

长江下游船舶溢油应急处理措施框架

介绍长江下游船舶溢油污染的现状,论述溢油污染对沿岸生态和环境的影响以及溢油防治研究的重要性。以长江南京段为例,分析影响江中及岸边事故溢油迁移转化规律的因素,提出船舶事故溢油应急处理措施的三个重要部分,即溢油模拟及污染区预测、溢油清除回收和溢油风险评价。针对三个部分提出了具体的研究内容,为国内各大中型江河不同河段的船舶溢油的研究提供参考。