锈蚀钢筋混凝土梁受剪性能评估

正确评价锈蚀钢筋混凝土梁受剪性能是科学评估锈蚀钢筋混凝土结构可靠性和耐久性的关键之一。从锈蚀钢筋混凝土梁斜截面受剪性能退化机理的角度,分析了影响锈蚀钢筋混凝土梁受剪能力的主要因素以及关于抗剪承载力研究方面目前存在的问题,并用已有的实验数据对现有的抗剪承载力计算模型进行了评估。研究表明:现有的钢筋锈蚀程度描述方法不能客观地反映自然锈蚀中的坑蚀,更无法考虑坑蚀引起的应力集中问题;基于名义应力或名义强度的锈蚀钢筋力学性能指标无法科学地地描述锈蚀钢筋的力学特征,锈蚀钢筋和混凝土之间粘结性能应考虑自然锈蚀中坑蚀以及严重锈蚀时锈胀现象的影响,已有的各种锈蚀钢筋混凝土抗剪承载力计算模型均存在一定的片面性。     

煤化工废水中油泥的聚结分离与水中有机物的去除效果

针对煤化工废水中存在的高浓度油及油泥的问题,本研究制备了高电荷、低聚合度的无机复合材料和低电荷、高聚合度的有机复合材料,探究无机、有机复合材料协同作用下对煤化工废水中油及油泥的聚结分离效果以及对废水中有机物的去除特性。结果表明,无机、有机复合材料在复合比例为500∶1的条件下,废水中油和固体悬浮物（SS）去除率分别达到55%和98%;现场试验发现,无机、有机复合材料对油含量1700～2000mg/L,SS含量为1500～2000mg/L的废水,油和SS的去除率一直稳定于50%和95%左右,表现出较好的稳定性;进一步对废水中典型有机物的去除效果研究可知,该复合材料同时也对废水中各类有机物有较好的去除效果,多环芳烃（PAHs）、苯系物和酚类物质的去除率可达到82.85%、41.9%和37.56%。可以发现,无机、有机复合材料可有效解决煤化工废水中油及油泥的去除问题,具有广阔的产业化应用前景。     

Near-infrared-shielding energy-saving borosilicate glass-ceramic window materials based on doping of defective tantalum tungsten oxide (Ta0.3W0.7O2.85) nanocrystals

NIR-shielding window materials were fabricated by direct embedding of Ta_0.3W_0.7O_2.85 nanocrystals in bulk borosilicate glass-ceramics during a facile melt-quenching process. Optical and thermal performance of the prepared windows can be adjusted by varying the concentration of H₂WO₄ and Ta₂O₅ in the starting materials. The optimized window fabricated from raw materials containing 4.5 mol% H₂WO₄ and 0.3 mol% Ta₂O₅ exhibited high visible light transmittance 74.4% and strong NIR-shielding ability ΔT = 68.9%. Its thermal insulation performance is much better than soda lime glass or ITO glass, and its visible light transmission is higher than cesium-tungsten-bronze-based film coated glass. The distribution of Ta_0.3W_0.7O_2.85 functional nanocrystals in the glass matrix was confirmed by sample characterization using XRD, Raman, XPS, HRTEM and EDS. The NIR-shielding property has been attributed to local surface plasmon resonance due to oxygen vacancies in the Ta_0.3W_0.7O_2.85 nanocrystals. This study sheds a light on fabricating energy-saving windows with a tunable NIR-shielding performance.     

Treatment of wastewater from acrylonitrile‐butadiene‐styrene (ABS) resin manufacturing by biological activated carbon (BAC)

Background: The wastewater originating from the production of acrylonitrile‐butadiene‐styrene (ABS) resin is a toxic and refractory industrial wastewater. The purpose of this work is to investigate the characteristics of adsorption and biodegradation of biological activated carbon (BAC) for ABS resin wastewater. Results: More than 80% of chemical oxygen demand (COD), total organic carbon (TOC) and organic nitrogen (Org‐N) was removed after the 100th run in BAC with the help of bioregeneration, and the treatment efficiency of BAC was higher than that of adsorption and biodegradation alone. The initial Org‐N was mainly transformed into NH₄⁺‐N, and the transform efficiency reached 65% after the 100th run. After bioregeneration, the COD and TOC removal efficiencies of BAC reactor reached 88.97% and 86.26%, respectively. The BAC had different bioregeneration efficiencies of 94.41, 64.82, 61.05 and 40.04% for 3, 3‐imminodipropiononitrile, 3, 3‐oxydipropiononitrile, α, α‐dimethyl‐benzylalcohol and acetophenone, respectively, which mainly resulted from the different polarity of the compounds. Conclusion: BAC could protect microorganisms from shock loadings of toxic, refractory and complicated ABS resin wastewater. The mechanism of the organic pollutants removal by BAC consisted of three phases including adsorption, bioregeneration and stability. © 2012 Society of Chemical Industry     

Transport of Dissolved Si from Soil to River: A Conceptual Mechanistic Model

This paper reviews the processes which determine the concentrations of dissolved silicon (DSi) in soil water and proposes a conceptual mechanistic model for understanding the transport of Si through soils to rivers. The net DSi present in natural waters originates from the dissolution of mineral and amorphous Si sources in the soil, as well as precipitation processes. Important controlling factors are soil composition (mineralogy and saturated porosity) and soil water chemistry (pH, concentrations of organic acids, CO₂ and electrolytes). Together with production, polymerization and adsorption equations they constitute a mechanistic framework determining DSi concentrations. We discuss how key controls differ across soil horizons and how this can influence the DSi transport. A typical podzol soil profile in a temperate climate is used as an example, but the proposed model is transferrable to other soil types. Additionally, the impact of external forcing factors such as seasonal climatic variations and land use is evaluated. This blueprint for an integrated model is a first step to mechanistic modelling of Si transport processes in soils. Future implementation with numerical methods should validate the model with field measurements.     

石墨相氮化碳改性及其光催化应用研究进展

石墨相氮化碳g-C3N4因其具有独特的电子结构、高催化活性、化学与热稳定性好、无毒且制备简易、不含金属等特点,受到全世界研究人员的关注,具有非常广阔的应用前景。本文介绍了石墨相氮化碳g-C3N4掺杂、半导体复合、染料敏化、片层剥离等改性研究方面的动态和主要成果,并介绍了其作为光催化材料应用的研究进展。     

Shear behaviour of structural silicone adhesively bonded steel-glass orthogonal lap joints

This paper outlines an experimental study on the shear behaviour of structural silicone adhesively bonded steel-glass orthogonal lap joints. In the combination of steel plate and glass panel to form a hybrid structural glazing system, bonded joints with structural silicones can provide certain flexibility which relieves stress peaks at critical points of glass panel. The cohesive failure and its related fracture pattern of test joints with varied geometries of adhesives are examined experimentally. It is shown that the presence of two failure modes as discrete voids and macro cracks is closely related to the adhesive thickness. The effects of geometric parameters of adhesives on the joint shear strength are examined. It is demonstrated that the joint shear strengths are increased with increased individual overlap length, reduced adhesive thickness or increased adhesive width while the shear deformation corresponding to maximum shear force is mostly influenced by adhesive thickness. Mechanical contributions for those effects are analyzed accordingly. Finally, an analytical formula allowing for the equilibrium of strain and force on the adhesive and adherend is proposed for the analysis of shear strength. It is demonstrated that calculated normalized shear force ratios predicted by proposed formula agree well with those from experimental results.     

煤气化及煤焦化过程中含酚废水的处理方法研究

煤气化及煤焦化是以提高煤炭的转化效率及便于运输为目的,在我国得到了广泛应用。煤气化及煤焦化过程中会产生大量含有苯酚和其他有机污染物的废水,严重威胁人类健康和生态环境,因此在排放之前必须进行严格处理。本文介绍了含酚废水的毒性,并着重概述了物理、化学及生物处理方法。     

Modeling of time to corrosion-induced cover cracking in reinforced concrete structures

Service life of the concrete structures depends on the protective action provided by the cover concrete against the susceptibility of the reinforcement to the corrosive environment. Depending on the level of the oxidation of metallic iron, corrosion products may have much greater volume than the original iron that gets consumed by the process of corrosion. This volume expansion is mainly responsible for exerting the expansive radial pressure at the steel-concrete interface and development of hoop tensile stresses in the surrounding concrete resulting ultimately in the through cracking of the cover concrete. This cover cracking would indicate the loss of the service life for the corrosion-affected structures. In the present paper, an attempt has been made to develop analytical models for predicting the time to cover cracking by considering the residual strength of the cracked concrete and the stiffness provided by the combination of the reinforcement and expansive corrosion products. The problem is modeled as a boundary value problem wherein the governing equations are expressed in terms of the radial displacement and the analytical solutions are presented considering a simple 2-zone model for the cover concrete viz. cracked or uncracked. The analytical models are then evaluated through their ability to reproduce available experimental trends and subsequently a sensitivity analysis has also been carried out to show the influence of the various variable parameters of the proposed models with reference to the experimental trends.     

餐厨垃圾溶剂热法制备负载铁生物质炭

以餐厨垃圾为原料运用溶剂热法制备了负载铁的球状生物质炭,系统研究了pH、醋酸锌（C₄H₆O₄Zn·2H₂O）与六水合三氯化铁（FeCl₃·6H₂O）投料质量比、碳化温度、碳化时间等条件对生物质炭制备的影响。在此基础上利用响应曲面法对生物质炭的制备条件进行了优化,分析了不同因素之间的交互作用。结果表明,在pH为2.26、C₄H₆O₄Zn·2H₂O与FeCl₃·6H₂O的质量比为0.51、碳化温度为203.96 ℃、碳化时间为2.92 h时,生物质炭的实际得炭率达到最大为56.82%,回归模型在研究区域内的水平显著,且预测的准确性较高。生物质炭的物相和形貌表征证明了四氧化三铁（Fe₃O₄）负载在球状生物质炭的表面,生物质炭的比表面积可以达到52 m²/g,负载Fe₃O₄相较于未负载Fe₃O₄的生物质炭对铜离子具有更好的吸附性,且吸附过程可以使用准二级动力学方程进行描述。