保温层下管道腐蚀监测系统及应用研究

为预防保温层下管道腐蚀带来的严重问题,必须采取有效措施进行腐蚀在线监测,以了解管道的剩余壁厚情况。在分析现有的腐蚀监测技术不足的前提下,基于γ射线数字扫描检测技术（GSDT）,研发了1套保温层下管道腐蚀在线监测系统,该系统可以实现对保温层下腐蚀管道剩余壁厚在线监测,并通过带保温层管道的检测试验和t-分布分析方法检验腐蚀监测系统的检测精度,最后以某化工企业为例,验证了该系统的有效性。结果表明:腐蚀监测系统可以实现对保温层管道剩余壁厚的监测,保温层和高密度介质不影响管壁厚度的测量结果,且使用所研发的腐蚀监测系统监测到的管道腐蚀速率与现场实际腐蚀速率基本一致。     

生物滤池同步净化低温高铁锰氨氮地下水

为实现低温（5~6℃）高铁锰氨氮[TFe：9~15mg/L,Fe²⁺：6~12mg/L,Mn²⁺：0.8~1.2mg/L,NH₃-N：0.9~1.4mg/L]地下水的生物同步净化,以水厂实地滤柱进行实验.结果表明,在该种水质下,以1.0,3.0m/h滤速启动生物滤柱,分别历经128,91d启动成功.铁和氨氮自启动之初出水即合格,锰的去除仍然是滤池成熟的决定性因素.溶解氧（DO）充足条件下,净化所需滤层厚度随氨氮浓度的升高而加厚,氨氮极限去除浓度为1.60mg/L.进水DO不足是限制氨氮继续提升的主要因素.滤速越大,锰的去除量越少,净化所需滤层越厚,滤柱极限运行滤速为8.0m/h.沿程分析发现,铁和锰的氧化去除存在显著分级,铁和氨氮在滤层内可同步氧化去除,锰的高效氧化去除区间相对滞后.     

某单井站场管道积液及腐蚀特性研究

为应对湿天然气管道存在的明显积液,导致管材腐蚀,目前经验性的检测点选择方式导致检测成本和工作量过大问题.基于某单井站场工况条件和现场壁厚检测数据,针对站场主管线,采用Fluent软件建模分析管线内液相分布规律.结果表明:含液率大小随原料气含水量、流量、压力的变化而呈正相关变化,运用Correl函数对现场壁厚检测数据和模...     

工业管道首次定期检验弯头壁厚减薄分析及检验对策

弯头壁厚减薄在工业管道首次定期检验过程中经常遇到,然而对其进行安全状况等级评定时经常评为4级,与实际不符.本文通过两个检验案例分析产生这种现象的原因,认为弯头的减薄并不都是由使用过程中造成的,而是弯头制造时产生的减薄,这种现象对工业管道的安全状况等级评定产生干扰,最后依据相关规范给检验人员提供解决措施,并有针对性的提出...     

翅片宽度及厚度对管板式热沉传热性能的影响

目的研究翅片宽度及厚度对管板式热沉性能的影响。方法利用Ansys中的Fluent模块,对管板式热沉不同宽度和厚度翅片的传热性能进行模拟仿真,分析翅片宽度和厚度对管板式热沉温度均匀性的影响。结果翅片越窄,热沉温度均匀性越好,且翅片平均温度越接近载冷剂温度。增加翅片厚度,可以强化传热,但热沉质量和制造成本也会上升,且增大到一定值时,传热效果增强不显著。结论热沉翅片的宽度和厚度对热沉的温度均匀性有很大的影响,翅片越厚,宽度越窄,热沉的温度均匀性越好,但不能一味采取增加厚度和减小宽度的方式来提高热沉温度均匀性,在设计热沉时,需结合其他因素综合选取翅片的宽度和厚度。     

Modelling radioactivity in the Irish Sea: From discharge to dose

In order to support authorised discharges of low level radioactive liquid effluent into coastal regions, mathematical models are required to robustly predict radiological impacts on critical groups of current and proposed changes to liquid discharges. The grid model presented here simulates the long term dispersion and transport of radioactivity discharged from the Sellafield site in Cumbria, UK, and the subsequent exposure of critical groups in Cumbria and across the Irish Sea in Northern Ireland. The fine grid of the model allows a good resolution of the seabed sediment distribution. This benefits the predictions for the last decades of low discharge level, when bed sediment can become a source of contamination by bringing back the legacy of past high discharges. This is highlighted by the dose comparison, where the predicted dose to Cumbria critical group follows well the dose estimated from environmental data during the low discharge level period.     

钢筋混凝土构件的最小隔火厚度

为了正确评估钢筋混凝土构件在实际火灾中的隔火作用,以一般室内火灾轰燃后的房间平均温度-时间曲线为升温曲线,以热传导理论为基础,以钢筋混凝土隔火构件的背火面的最高温度恰好达到220℃为判定准则,用数值计算方法给出钢筋混凝土隔火构件的最小厚度,并用最小二乘法导出其计算公式.火灾房间火灾荷载越大,开口因子越小,最小隔火厚度越大;反之越小.该文所给最小厚度可用于钢筋混凝土分隔构件的性能化耐火设计与评估:当火灾荷载密度较大,开口因子较小时加大构件的厚度以获得安全性,反之,减小厚度以获得经济性.     

Tracing operational conditions for the Ecologically Sustainable Economic Development: the Pareto optimality and the preservation of the biological crucial levels

The operational designing of Environmentally Sustainable Economic Development (ESED) emerges as an urgent and demanding task. Even though ESED has paved the way for thought-provoking and constructive scientific dialogue, appeal for designing an operational ESED is still lagging behind the needs of contemporary societies, leaving much to be desired. With this in mind, the present paper will aim at delineating principles for the operational application of ESED. First, the preservation of crucial properties of environmental functions and ecosystems, emerges as a prime condition of ESED. The second condition concerns the provision of the economic process with sufficient natural inputs; in this context, the paper intends to trace certain operational tenets governing the use of natural resources. Finally, the appropriate institutional settings for the operational design of ESED are traced. Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue     

我国早晨与傍晚的大气边界层厚度研究

首先探讨了常规气象资料计算大气边界层厚度的方法,然后利用全国１２５个无线电探空站的观测资料,计算了我国早晨与傍晚时的大气边界层厚度ｈ,并分析了ｈ的地区分布与季节变化特征。结果表明,华南地区边界层厚度年平均值最大（ｈ＞５００ｍ）;陕甘宁地区最小（ｈ＝３１８ｍ）;多数地区的ｈ值在冬季最小而夏季或春季最大。     

Dynamic modeling and bifurcation analysis for the methyl isocyanate hydrolysis reaction

The aim of this work was to characterize the methyl isocyanate hydrolysis reaction and to identify its operational criteria. The parametric sensitivity and dynamic stability methodologies were performed at the Bhopal disaster circumstances, over the relevant operating parameter space. Stable and unstable conditions, bifurcations points, turning points and oscillatory behavior were determined. The combined methodology give useful guidance on the operative conditions selection and the appropriate strategy to overcome hazardous situations. The obtained results demonstrated high sensitivity to small perturbations (thermal runaway) and prevalent oscillatory behavior. Moreover, the following critical parameters for the studied dynamic system were defined: the inverse residence time of 1.5700103 and the heat transfer coefficient of 752.394.