Ultrasonic waste activated sludge disintegration for improving anaerobic stabilization

The pretreatment of waste activated sludge by ultrasonic disintegration was studied in order to improve the anaerobic sludge stabilization. The ultrasound frequency was varied within a range from 41 to 3217 kHz. The impact of different ultrasound intensities and treatment times was examined. Sludge disintegration was most significant at low frequencies. Low-frequency ultrasound creates large cavitation bubbles which upon collapse initiate powerful jet streams exerting strong shear forces in the liquid. The decreasing sludge disintegration efficiency observed at higher frequencies was attributed to smaller cavitation bubbles which do not allow the initiation of such strong shear forces. Short sonication times resulted in sludge floc deagglomeration without the destruction of bacteria cells. Longer sonication brought about the break-up of cell walls, the sludge solids were distintegrated and dissolved organic compounds were released. The anaerobic digestion of waste activated sludge following ultrasonic pretreatment causing microbial cell lysis was significantly improved. There was an increase in the volatile solids degradation as well as an increase in the biogas production. The increase in digestion efficiency was proportional to the degree of sludge disintegration. To a lesser degree the deagglomeration of sludge flocs also augmented the anaerobic volatile solids degradation.     

By-products formation during drinking water disinfection: a tool to assess disinfection efficiency?

In drinking water treatment, the inactivation of microorganisms increases with increasing disinfectant exposure (product of concentration and contact time, CT). Also, the formation of undesired (toxic) disinfection by-products increases with CT. The present study proposes a new concept that uses this undesired side effect of chemical water disinfection for a fast and reliable test of treatment efficiency. In laboratory systems, bromate formation during ozonation and the formation of trihalomethanes during chlorination were used to calculate the disinfectant exposure, which is a measure for the achieved degree of disinfection.     

异步轧制对表面纳米化316L不锈钢组织和性能的影响

采用表面机械研磨处理(SMAT)在316L不锈钢上制备出纳米结构表层,然后在室温对其进行80％形变量的异步轧制(CSR),研究了CSR处理后表层组织和性能的变化．结果表明：经过60min SMAT后,样品表面形成了一定厚度的纳米晶层,晶粒尺寸为10—30nm．对其进行80％形变量的CSR后,表层组织仍为纳米晶组织,但纳米晶尺寸更加均匀、细小(为5—15nm),表面粗糙度显著下降;纳米表层硬度略有提高,但基体硬度显著提高;在0．05mol／L H2SO4 0.25mol／L Na2SO4腐蚀介质中的耐腐蚀性能比SMAT后的样品有明显改善,但均低于原基材．     

DYNAMIC MECHANICAL BEHAVIOURS OF HIGH Mo AUSTENITIC STAINLESS STEEL DURING HOT DEFORMATION

The dynamic mechanical behaviours of super low carbon high Mo austenitic stainless steel(00Cr20Nil8Mo6CuN)during hot deformation have been studied by using Formaster-Presshot working simulator. The hot deformation equation, as well as the relationship between peakstrain, peak stress and Zener-Hollman parameter, together with the deformation activationenergy have been resulted through the experiments.     

复合材料层压板的超声相控阵检测

为满足复合材料层压板在厚度方向不存在加工余量及其缺陷特征的需求,设计了具有不同大小和埋深的人工缺陷的复合材料层压板试块,利用超声相控阵检测法对该试块进行100%扫查。C扫图像显示所有人工缺陷均能被检测出来,且位于第一与第二层碳布之间3mm的最小缺陷清晰可辨。经实际应用表明,超声相控阵检测法可用于复合材料层压板的无损检测。     

含Li的高锌Al-Zn-Mg-Cu合金的时效行为

对化学成分(质量分数，％)为Al-11.8Zn-2．9Mg-2．8Cu-1．17Li的合金分别在110℃、120℃、130℃、140℃、150℃、160℃和180℃进行人工时效，并对部分试样进行透射电镜观察。结果表明，适量Li对高合金含量的Al-Zn-Mg-Cu合金的沉淀相形核影响不大，但可抑制其长大。高的合金含量，可以使合金在时效过程中析出高密度细小的沉淀相，从而达到很高的硬度，但不能完全固溶于基体的合金元素在晶界形成粗大的第二相。     

Hard x-ray transmission crystal spectrometer at the OMEGA-EP laser facility

The transmission crystal spectrometer (TCS) is approved for taking data at the OMEGA-EP laser facility since 2009 and will be available for the OMEGA target chamber in 2010. TCS utilizes a Cauchois type cylindrically bent transmission crystal geometry with a source to crystal distance of 600 mm. Spectral images are recorded by image plates in four positions, one IP on the Rowland circle and three others at 200, 400, and 600 mm beyond the Rowland circle. An earlier version of TCS was used at LULI on experiments that determined the x-ray source size from spectral line broadening on one IP positioned behind the Rowland circle. TCS has recorded numerous backlighter spectra at EP for point projection radiography and for source size measurements. Hard x-ray source size can be determined from the source broadening of both K shell emission lines and from K absorption edges in the bremsstrahlung continuum, the latter being a new way to measure the spatial extent of the hard x-ray bremsstrahlung continuum.     

粉末粒度对碳/碳基体上羟基磷灰石涂层的影响

采用等离子喷涂技术在碳纤维增强碳复合材料(简称碳／碳复合材料)上制备了羟基磷灰石涂层,研究了原始粉末粒度对涂层的表面形貌、剪切强度、相组成等方面的影响,并分析了涂层与基体的界面结合状况。结果表明：采用粗粉末喷涂后得到的涂层结合强度较高．结晶程度也较高,但涂层与基体的结合机制仍为机械嵌合。     

同步辐射高分辨率衍射光束线的设计

介绍了第三代同步辐射高分辨率X射线衍射光束线的总体设计。给出了高分辨率衍射的基本原理并描述了获得确定光子能量的近平行高强度X射线光束线所必需的光学元件。特别是用X射线动力学理论,解释了双晶及四次反射晶体单色器。作为一个实例,介绍了将于2009年开始在德国汉堡运行的一个新的同步辐射源PETRAⅢ的高分辨率衍射(HighRes)光束线的设置情况。通过优化光学部件,对微米尺寸光束,q空间的分辨减小到Δq=10^-5 nm^-1,光通量大于10¹¹ cts/s。     

超长混凝土结构的研究与应用

本文结合南京国际展览中心工程 ,对超长混凝土结构的设计、温度应力的有限元分析以及施工措施等进行了深入的探讨 ,并介绍了长期测试结果。