Accounting for the uncertainties in the estimation of average shear wave velocity using V S– N correlations

Site-specific seismic hazard analysis is crucial for designing earthquake resistance structures, particularly in seismically active regions. Shear wave velocity ( V _S) is a key parameter in such analysis, although the economy and other factors restrict its direct field measurement in many cases. Various V _S–SPT– N correlations are routinely incorporated in seismic hazard analysis to estimate the value of V _S. However, many uncertainties question the reliability of these estimated V _S values. This paper comes up with a statistical approach to take care of such uncertainties involved in V _S calculations. The measured SPT– N values from all the critical boreholes were converted into statistical parameters and passed through various correlations to estimate V _S at different depths. The effect of different soil layers in the boreholes on the Vs estimation was also taken into account. Further, the average shear wave velocity of the top 30 m soil cover ( V _S30) is estimated after accounting for various epistemic and aleatoric uncertainties. The scattering nature of the V _S values estimated using different V _S– N correlations was reduced significantly with the application of the methodology. Study results further clearly demonstrated the potential of the approach to eliminate various uncertainties involved in the estimation of V _S30 using general and soil-specific correlations.     

工程教育认证背景下的《环境影响评价》课程教学改革

《环境影响评价》是环境科学与工程专业核心课程之一,其教学目标的达成对人才培养至关重要。为解决市场需求与课程大纲内容相脱节的问题,本文结合现有课程大纲知识、能力、素质目标开展问卷调查,以需求为导向,反向设计教学内容,并此为依据从教学内容、教学模式等方面开展课程教学改革。     

Separation of hematite from banded hematite jasper (BHJ) by magnetic coating

The separation of iron oxide from banded hematite jasper(BHJ) assaying 47.8% Fe, 25.6% Si O2 and 2.30%Al2O3 using selective magnetic coating was studied. Characterization studies of the low grade ore indicate that besides hematite and goethite,jasper, a microcrystalline form of quartzite, is the major impurity associated with this ore. Beneficiation by conventional magnetic separation technique could yield a magnetic concentrate containing 60.8% Fe with 51% Fe recovery. In order to enhance the recovery of the iron oxide minerals, fine magnetite, colloidal magnetite and oleate colloidal magnetite were used as the coating material. When subjected to magnetic separation, the coated ore produces an iron concentrate containing 60.2% Fe with an enhanced recovery of56%. The AFM studies indicate that the coagulation of hematite particles with the oleate colloidal magnetite facilitates the higher recovery of iron particles from the low grade BHJ iron ore under appropriate conditions.     

油库发油过程中的HSE管理

叙述了石油库在发油过程中的HSE管理；发油过程中的危害识别，包括识别范围和内容；发油过程中风险评价的常用基本方法和常见问题；发油过程中危险源的管理控制，包括建立危险源网络图、加强现场监控和制定应急预案。     

BaxSr（1—x）TiO3多层膜椭偏光谱研究

用溶胶－凝胶技术在Bi(100）衬底上制备了单层和渐变型多层的BaxSr(1-X)TiO3薄膜，其膜层组分分别为：Ba0.7Sr0.3TiO3,Ba0.8Sr0.2TiO,Ba0.9Sr0.1TiO3,BaTiO3，对生长制备出的多层BaxSr(1-X)TiO3薄膜进行了变角度椭偏光谱测量，通过椭偏光谱解谱分析研究，首次得到了BaxSr(1-X)TiO3多层膜结构不同膜层的膜厚和光学常数，其结果显示：椭偏光谱分析得到的不同膜层的膜厚与卢瑟福背向散射测量得到的结果基本相符；渐变型多层膜中BaTiO3薄膜的折射率比单层BaTiO3薄膜折射率大许多，与体BaTiO3的折射率相接近，这说明渐变型多层膜中BaTiO3薄膜的光学性质与体材料的光学性质接近。     

工业废水的生化处理工艺

1　引言多年来 ,欧盟与各国政府都不断地加强有关污水处理的法规 ,法规规定产生污水的企业必须在排放污水前加以处理。然而 ,在许多场合 ,由于至今尚无令人满意的方法来彻底净化污水 ,而且只要这些生产企业正在认真地寻找解决问题的方法 ,这些规定也不是一概而论的。因此 ,在实施法规的过程中就导致了某种程度的宽松度。这些情况将会结束 ,在不久的将来 ,这些法规将会得到强有力的执行。现在大多数公司的环境问题很严重 ,当然污水处理也确实有其商业上的原因。最主要的是这些公司除非找到一个可行的处理污水的方法 ,否则不允许他们继续生产…     

采用反相方法测试台架测定3．3kV IGCT的特性

采用反相方法测试台架在实际工作条件下，对ABB公司提供的实验性3．3kV IGCT进行了特性测定.这种器件在硬开关运行下的导通损耗非常小，开关损耗也降低了.这就表明一种新型大功率/中电压半导体器件已经问世，它们可以用于较高开天频率(超过1kHz)和大电流工况，以改善大功率变换器的性能.     

覆盖层厚度对巷道周围应力分布的影响及巷道间相互作用的仿真

给出了覆盖层厚度对巷道周围应力分布的影响及巷道间相互作用的计算机仿真，用三维有限元法分析了在不同覆盖层厚度下巷道周围的应力分布和两个巷道之间不同距离下的相互作用。数值模拟表明了巷道周围应力分布和应力集中系数随覆盖层厚度增加的变化规律，找到了两巷道之间的距离的临界值，当两巷道间距离大于该临界值时，它们之间的相互作用消失。