Thin-film composite forward osmosis membranes with substrate layer composed of polysulfone blended with PEG or polysulfone grafted PEG methyl ether methacrylate

To advance commercial application of forward osmosis (FO), we investigated the effects of two additives on the performance of polysulfone (PSf) based FO membranes: one is poly(ethylene glycol) (PEG), and another is PSf grafted with PEG methyl ether methacrylate (PSf-g-PEGMA). PSf blended with PEG or PSf-g-PEGMA was used to form a substrate layer, and then polyamide was formed on a support layer by interfacial polymerization. In this study, NaCl (1 mol?L^–1) and deionized water were used as the draw solution and the feed solution, respectively. With the increase of PEG content from 0 to 15 wt-%, FO water flux declined by 23.4% to 59.3% compared to a PSf TFC FO membrane. With the increase of PSf-g-PEGMA from 0 to 15 wt-%, the membrane flux showed almost no change at first and then declined by about 52.0% and 50.4%. The PSf with 5 wt-% PSf-g-PEGMA FO membrane showed a higher pure water flux of 8.74 L?m^–2?h^–1 than the commercial HTI membranes (6–8 L?m^–2?h^–1) under the FO mode. Our study suggests that hydrophobic interface is very important for the formation of polyamide, and a small amount of PSfg-PEGMA can maintain a good condition for the formation of polyamide and reduce internal concentration polarization.

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Comprehensive evaluation of the stability of the left-bank slope at the Baihetan hydropower station in southwest China

The stability of the left-bank slope is a crucial geological engineering problem at the Baihetan hydropower station, China. Due to continuous excavations on the rock slope, different regions of the surrounding rock mass undergo varying degrees of unloading deformation. It is important to assess the stability of the rock slope from a macroscopic viewpoint by investigating its deformation characteristics and mechanisms. Therefore, in this work, microseismic (MS) monitoring was first employed to detect the progressive rock mass damage in the rock slope subjected to excavation, including the initiation, propagation, coalescence, and interaction of rock microfractures. Numerical modeling was subsequently performed to understand the deformation and failure mechanism of the rock slope. Moreover, traditional surveying approaches (i.e., multiple-point extensometers and inclinometers) and field observations were also used to analyze the deformation and failure characteristics of the rock slope. The MS monitoring results showed that spatiotemporal regularities in the evolution of seismic source locations were indicators of deformation failure and potential sliding surfaces. MS event clustering can be used to delineate activated pre-existing geological structures (i.e., LS331 and LS337). The simulation results show that the deformation and failure characteristics of the rock slope are mainly controlled by pre-existing weak structural planes (i.e., the intraformational faulted zones LS3319, LS331, and LS337 and fault F17). These results agree well with the results of geological data and conventional monitoring data. Our study reveals that an integrated approach combining MS monitoring, numerical modeling, traditional surveying, and field observations leads to a better understanding of the behavior of the rock slope under the influence of excavation as well as greater control of the working faces, ensuring safety under complex geological and excavation conditions.     

Progress in Technology and Catalysts for Continuous Stirred Tank Reactor Type Slurry Phase Polyethylene Processes

High-density polyethylene (HDPE) have been widely used as materials of hollow molded articles, extrusion molded articles, films and sheets. The properties of HDPE vary depending on its application fields and processing methods thereof. Approximately 50 million tons of HDPE are produced annually around the worldwide by slurry phase processes. In this paper, the status of slurry phase polyethylene processes in China is briefly introduced. Two of the most important licensers of continuous stirred tank reactor (CSTR) type slurry phase polyethylene processes, namely, Hostalen (Licensed by Basell), CX (Licensed by Mitsui), with a dual- or three-reactor are reviewed. The merits and demerits of the examined polyethylene production technologies are discussed in detail. Catalyst is a key of polyolefin technology. It does have an extremely close relationship with the performance of polyethylene. The characteristics and disadvantages of different catalysts for the two processes are summarized for comparison, including the PZ and RZ catalysts of Mitsui, the BCH and BCE catalysts of Beijing Research Institute of Chemical Industry, the TH series catalysts of Basell. Some advices on the development and application of HDPE catalysts for the slurry process are proposed.     

Lake Turkana,major Omo River developments,associated hydrological cycle change and consequent lake physical and ecological change

This study aimed to explore Lake Turkana's ecological reliance on hydrology and to determine the hydrological changes and consequences arising from the major hydropower and irrigation developments in the lake's basin. The major developments on Ethiopia's Omo River are especially significant as this river provides over 80% of the lake's annual freshwater influx and associated nutrients. The cascade of hydropower dams permanently dampens the natural hydrological cycles and lake level variability. The driving force of the flood influx to the lake is curtailed and the pattern of lake currents will adjust. Ultimately 80% of the river inflow to the lake will be regulated. Large volumes of water are required to initially fill the hydropower dam reservoirs. During 2015–16 when the huge Gibe III reservoir was filled, Lake Turkana's water level declined 2?m.The study has shown that large-scale irrigation schemes in the Lower Omo can potentially abstract 50% of the Omo River water, and that this would cause the lake level to shrink permanently to the detriment of the lake ecology. Possible lake level drops of over 15?m are demonstrated. The basin's natural capital is being replaced by large-scale plantation developments. The hydrological changes are drastic and the ecological consequences on Lake Turkana have not been fully understood. Without serious mitigation measures, Lake Turkana is a potential African Aral Sea disaster in the making, emulating what has happened to other great lakes such as Lake Chad.     

Decomposition of electricity consumption in China by primary component analysis

The empirical relationship between electricity consumption and gross domestic product, population, the product of primary industry, second industry, and tertiary industry are investigated. The strong multicollinearity among EC’s affecting factors does not meet the criteria of the ordinary least square regression (OLS) regression model. Principle component analysis is used to eliminate multicollinearity. Three principle components with no multicollinearity can explain 99.34 % of affecting factors’ variance. The three principle components seemed as independent, and EC seemed as dependent variables when OLS regression is employed. The results show that: gross domestic product, primary industrial production value, second industrial production value, and tertiary industrial production value codetermined the trend of electricity consumption, while the proportion of primary industrial production value, second industrial production value, and tertiary industrial production value and population codetermined the starting point and fluctuation of electricity consumption; the economic scale is the mainly affecting factors on electricity consumption; as some parts of electricity consumed by primary industry are not included in the state grid, there is an illusion that the primary industry can produce electricity.     

吸力式沉箱基础抗拔破坏标准研究与分析

吸力式沉箱基础是一种用于海上浮式结构的新型基础型式,因其具有运输与施工方便、节省工期、可重复使用及造价低等优点,所以在海洋工程中得到了较为广泛的应用,其承载性状也是目前的研究热点之一。关于吸力式沉箱基础,至今尚未有一个得到广泛认可的抗拔破坏标准,也没有专门针对其破坏标准的研究报道,因此探讨吸力式沉箱基础的抗拔破坏标准对其承载性状研究有重大意义。结合荷载作用点位置和荷载作用方向两个因素对目前国内外已有的吸力式沉箱基础抗拔破坏标准进行了综述分析,并指出了现有吸力式沉箱基础抗拔破坏标准存在的问题和研究发展的方向。     

Aluminum titanate based ceramics from aluminum sludge waste

This work aims at obtaining aluminum titanate-based ceramics (Al₂TiO₅: AT) composites from industrial wastes. Al-sludge waste and rutile ore were used as rich sources of alumina and titania instead of pure materials. Sludge-(0–40 wt%) rutile mixtures were mixed, formed and fired at 1350 °C for various times. Phase composition, microstructure, densification, mechanical and thermal behaviors of the obtained AT composites have been investigated. Complete conversion of the starting materials to AT with bulk density of 3.199 g/cm³, compressive strength and modulus of rupture of 326.425 MPa and 30.84 MPa, respectively and very low CTE (−0.927*10⁻⁶ K⁻¹) were achieved by firing the sludge-(30 wt%) rutile at 1350 °C for 4 h. These results suggest that the obtained AT-ceramics from Al-sludge waste-rutile ore are a promising and an ecofriendly route.     

负载羧基化球状介孔纳米颗粒TFN膜的研究

在薄层复合膜(thin-film composite membrane, TFC膜)中引入无机纳米颗粒，形成薄层纳米复合膜(thin-film nanocomposite membrane, TFN膜)，近几年作为反渗透膜开始应用于水处理研究。但是无机纳米颗粒在TFC膜中的性能的不稳定性和膜的机械强度等变成了突出问题。合成制备了粒径约为110 nm修饰羧基的介孔氧化硅球状纳米颗粒(MSN—COOH)，并将其成功地化学键合在TFC膜的表面功能层交联网络中。与TFC膜相比，键合有MSN—COOH的TFN膜，水通量提高了56.2%，保持高脱盐率；由于单分散介孔纳米颗粒表面亲水官能团的引入，使膜表面的亲水性有很大程度提高，单分散介孔纳米颗粒在基体中的有序排列，使膜表面粗糙度降低，提高了膜的抗污染能力。与普通TFN膜相比较，具有更好的稳定性和柔韧性，可以在长时间高压过滤操作下保持稳定。