Prediction of BLEVE mechanical energy by implementation of artificial neural network

In the event of a BLEVE, the overpressure wave can cause important effects over a certain area. Several thermodynamic assumptions have been proposed as the basis for developing methodologies to predict both the mechanical energy associated to such a wave and the peak overpressure. According to a recent comparative analysis, methods based on real gas behavior and adiabatic irreversible expansion assumptions can give a good estimation of this energy. In this communication, the Artificial Neural Network (ANN) approach has been implemented to predict the BLEVE mechanical energy for the case of propane and butane. Temperature and vessel filling degree at failure have been considered as input parameters (plus vessel volume), and the BLEVE blast energy has been estimated as output data by the ANN model. A Bayesian Regularization algorithm was chosen as the three-layer backpropagation training algorithm. Based on the neurons optimization process, the number of neurons at the hidden layer was five in the case of propane and four in the case of butane. The transfer function applied in this layer was a sigmoid, because it had an easy and straightforward differentiation for using in the backpropagation algorithm. For the output layer, the number of neurons had to be one in both cases, and the transfer function was purelin (linear). The model performance has been compared with experimental values, proving that the mechanical energy of a BLEVE explosion can be adequately predicted with the Artificial Neural Network approach.     

海拉尔盆地地震勘探环境影响分析及控制措施探讨

文章以海拉尔盆地草原地震勘探为例,结合项目环境影响评价、评估工作的开展,找出地震勘探主要环境影响和生态破坏因素,通过分析其在地震生产过程中产生的环境影响及危害,提出相应的控制措施及工作建议。文章侧重于草原生态环境影响恢复与地震勘探环境保护控制技术的研究,探讨在生态环境脆弱地区实施绿色勘探的可行性,阐明实施清洁生产、营造和谐生态油田的环境保护措施。     

近50年江苏省夏季高温热浪的时空分布特征分析

根据江苏省1955-2007年7-9月逐日最高气温资料,分别以日最高气温≥35℃的高温天数、持续3d、5d的高温过程、平均最高气温为指标,建立了各站点的高温日数、高温强度的时间序列。分析发现,该省20世纪90年代中后期以来处于一个偏热期,苏州等城市近几年高温次数明显增加,而西南区域南京等城市夏季的最高气温则有下降趋势;同时,运用小波分析方法对该省高温时空分布的周期性进行了分析,结果表明,江苏省年平均最高温度变化中5～6a的周期振荡在各地区中反映得比较明显。     

基于最佳摄动量法的桩基承载力反演

通过高应变动力试桩法来获得桩土参数是目前比较流行的试桩方法,其原理主要是通过以桩顶的实测信息来反演桩土参数,其中比较成熟的CAPW APC法主要用试凑法来反演桩土模型参数,其反演结果呈现一定的随机性且正确性过于依赖操作者经验。本文尝试以CAPW APC法所采用比较成熟的桩土模型为基础,引入基于最佳摄动量法的局部优化方法来反演桩土参数。在弹性波波动方程隐式差分的基础上,对反演参数采用摄动展开并推导出参数反演的递推公式,最后给出合适的反演算法。考虑到初始参数对局部优化方法的影响,根据场地的实际情况选取合适的初始模型,计算显示可以获得比较理想的结果,说明本法是对桩基动测方法的一种有效的新尝试。     

固体声在建筑物内的衰减、反射和透射

固体声波在建筑物内传播会产生衰减、反射和透射。文中对居民楼内的固体传声进行了理论分析,认为建筑物内固体声传播过程中存在扩散衰减、结构突变衰减和阻尼损失衰减。同时,固体声波在墙体或楼板内反射使声能密度大大增加;固体声在传播过程中会向空气中透射,使得居民室内产生结构噪声污染。文中对某小区变压器房结构噪声进行理论分析和计算,预测了变压器房上方室内的结构噪声级,计算结果表明,当设备基础上振动级达到90 dB时,二楼居民室内的结构噪声级可达到41.3 dB,这对人们的正常生活会产生十分不利的影响。计算值与实际测量值较为吻合,说明理论分析和预测计算基本是可信的。     

An analysis of seismic risk from a tourism point of view

Global awareness of natural calamities increased after the destructive Indian Ocean tsunami of December 2004, largely because many foreigners lost their lives, especially in Thailand. This paper explores how best to communicate the seismic risk posed by different travel destinations to crisis management personnel in tourists' home countries. The analysis of seismic risk should be straightforward enough for non-specialists, yet powerful enough to identify the travel destinations that are most at risk. The output for each location is a point in 3D space composed of the natural and built-up environment and local tourism. The tourism-specific factors can be tailored according to the tourists' nationality. The necessary information can be collected from various directories and statistics, much of it available over the Internet. The output helps to illustrate the overall seismic risk conditions of different travel destinations, allows for comparison across destinations, and identifies the places that are most at risk.     

浙北及邻近地区应力场数值模拟与地震危险区预测

根据构造地质学、地震地质学的考察和观测结果 ,结合构造单元、地震活动分区和研究区位置确定计算模型的范围 ,选定一个构造骨架 ,确定计算模型的边界形状和几何参数。然后参考地震震源机制解结果和新构造运动特征 ,选定模型边界条件 ;参考岩石力学实验结果 ,确定模型的物理参数。最后利用线弹性二维有限元程序计算了各节点位移、各单元应力应变及应变能增量。通过分析应力应变场和应变能增量划分出 2个地震危险区。     

面波的尾波衰减经验关系和震级

从南京地震台DK - 1中长周期地震记录 ,取得地震面波的尾波地动双振幅A随尾波推移时间τ(自图上P波起算 )的衰减关系 ,并以MS(PEK)震级标度为基准 ,定义面波的尾波震级MSC=0 88lgAH+1 51lgτH+0 73 =0 86lgAZ+1 47lgτZ+0 76 ,尾波的多点测量改善了MSC的精度 ,震级标准差S=0 1 2。     

江苏省数字地震台网在考核运行期间的地震编目

江苏省数字地震台网从 1999年 6月至 9月记录到的自动触发和人工截取的 4 13条事件中 ,编报出 94个地震事件 ,其中 ,可用于数字网和模拟网进行地震三要素对比的地震事件有 35个。最终产出一份完整的地震目录和台网观测报告。进而从地震编目角度对数字地震台网资料和模拟台网资料确定地震三要素的可衔接性进行了尽可能的对比论证。     

超声导波技术在长输管道跨越段腐蚀检测中的应用

管道跨越段的检测一直是管道检验检测的难题之一,本文运用英国TWI集团Teletest Focus+MK4导波设备,对某在役的长输管道,综合选择了河流、沟壑、高速公路、水渠等多种不同服役环境管段,管径DN200至DN350不等6个跨越段进行检测,并进行案例分析.实践表明,导波检测技术对跨越段管道的单边检测距离在100m左...