污水管道强化通风技术的CFD模拟及现场验证

污水管道通风不畅是管道厌氧产生有害气体并不断富集的主要原因。为此,提出了在上下游建筑立管并设置风机以增强污水管道通风的应对方法,且以西安市某建筑的部分污水管道为例,建立了通风效能的计算流体力学(CFD)模型,并进行了现场实验验证。现场实验结果证明了通风效能和CFD模拟方法的可靠性。模拟结果表明：CFD模拟与实测结果偏差小于7.0%;增强通风量的2.3%通过立管近处检查井孔溢出;所选风机对污水管道的影响区域为510～750 m;风机运行对建筑横支管水封损耗小于国内规定的水封破坏值;风机运行安全可行。以上研究结果可为疏导城市建筑污水管道中的有害气体,控制污水管道安全风险提供参考。     

Persistent organic pollutants (POPs) in Caspian seals of unusual mortality event during 2000 and 2001

Persistent organic pollutants including organochlorine pesticides, PCBs, and PCDDs/DFs were determined in the blubber of Caspian seals, which died during an outbreak of canine distemper virus in 2000 and 2001. DDTs were the predominant contaminants that ranged from 3.1 to 560 microg/g lipid. A negative correlation was observed between concentration of contaminants and blubber thickness. During spring, as the blubber layer becomes thin after breeding and moulting, seals may face higher risk due to the increased concentration of organochlorines in their bodies. TEQs in the blubber of Caspian seals (10-340 pg TEQ/g) were lower than those in seals from other locations, suggesting that toxic effects of these contaminants are a deal less in the present population and they are unlikely to be linked to mass mortality. The levels of PCBs and pesticides in Caspian seals, however, comparable to those in other aquatic mammals that have suffered from epizootics, might pose a risk of immunosuppression.     

增压器式超高压水射流切割机产品化体会及展望

作为我国高压水射流切割机的第一个产品即“大地水刀”,已进入市场两年多了。笔者以此为背景,介绍增压器式水切割机的超高压发生器及切割部分;讨论其主要部件、零件结构设计及关键技术。尤其在产业化中,对高压缸体疲劳寿命和高压动密封可靠性等问题解决方案作深入探讨;给出在相关技术方面近期的发展。最后,结合我国水切割机技术的提高和推广,提出初步的看法和建议。     

负压反吹布袋除尘器三通换向阀的研究与应用

本文介绍负压反吹风布袋除尘器中一种新型的三通换向阀.该阀门具有结构简单、密封性能好,切换迅速、维修方便等特点.     

基于动态气封壁反应器的湿式氧化工艺

将动态气封壁反应器应用于湿式氧化,利用空气与亚临界水的界面张力将腐蚀性反应液局限在多孔壁以内实现“气封”,并在9.1~10.9 MPa、242~338℃的实验条件下得到了验证。对应的湿式氧化工艺在处理固含量2.9%的城市污泥和回收固含量1.6%~10.5%的污泥用活性炭的实验过程中,设备运行稳定,“防腐抗堵”性能良好。进一步分析表明,动态气封壁反应器能强化气液混合、降低设备投入和减少系统能耗,具有一定的开发潜力。但由于受限于反应器体积,过氧量和停留时间不足,导致处理效率偏低,需进一步优化改进。     

浮盘密封圈的原油挥发及结构优化的研究

根据我国大型浮顶储罐的特点,分析浮盘密封圈内油气的形成和集聚过程,总结浮盘密封圈在运行中出现的问题;指出密封圈内的油气挥发是气液相动态平衡的过程,当前浮盘密封圈的主要缺陷是密封圈内油气空间较大和在运行中无法保证有效密封;消除密封圈内原油的气液相界面是抑制密封圈内原油挥发的根本,减少风、气温变化等外界因素对密封圈内原油挥发的影响是降低密封圈内油气浓度的关键;消除密封圈内部的油气空间、消除密封圈内可能存在的放电点、增强密封结构的稳定性是密封圈结构优化的主要途径。     

窗用材料与建筑节能

门窗对建筑耗能的影响,近年已引起人们的关注,为了寻求窗用材料与建筑节能的对应关系,对各种窗用材料与节能的关系进行了理论分析,并对其关系进行了较详细的讨论.探讨其节能规律,以其为节能窗的设计提供一些可靠依据.     

某O型密封圈的双参数加速退化规律分析

目的研究某O型密封圈在温度影响下的退化规律。方法以压缩永久变形率和压缩应力松弛率作为参数,在50、60、70、80℃对某O型密封圈进行恒定应力加速退化试验,根据退化数据建立退化轨迹模型,确定伪失效寿命的分布,结合阿伦尼斯模型外推20℃时某O型密封圈的寿命,并进行可靠性分析。结果某O型密封圈的性能退化过程具有可加速性,它的伪失效寿命服从正态分布。根据压缩永久变形参数外推20℃下、0.9可靠度时,某O型圈的寿命为8.695年,根据压缩应力松弛参数外推的寿命为8.748年,根据双参数不相关的情况外推的寿命为8.655年,3次评估结果较为接近。结论文中使用的试验方法和数据处理方法能有效地评估某O型密封圈的寿命。考虑两个参数不相关情况时,得到的评估结果会小于单参数情况下的评估结果。     

温度-湿度-高度环境对航天火工装置性能的影响

目的 研究温度-湿度-高度环境对航天火工装置密封性能的影响机理.方法 调研"温度-湿度-高度"环境的由来,对比不同标准中试验方法的差异,分析其作用过程,并分析两起因温度-湿度-高度环境导致的火工装置失效案例的故障原因及机理.结果 由于低温、低压与高温、高湿多次相互转化的过程,装置表面的冷凝水因"负压"特性被"压"入装置...     

Effects of methyl-, phenyl-, ethylmercury and mercurychlorid on immune cells of harbor seals （Phoca vitulina）

Mercury (Hg) is present in the marine environment as a natural metal often enhanced through human activities. Depending on its chemical form, Hg can cause a wide range of immunotoxic e ects. In this study, the influence of methyl-, ethyl- and phenylmercury as well as mercurychloride on immune functions was evaluated. Two parameters of cellular immunity, proliferation and mRNA cytokine expression of interleukin-2, -4, and transforming growth factor , were investigated in harbor seal lymphocytes after in vitro exposure to Hg compounds. While all Hg compounds had a suppressive e ect on proliferation, di erences between juvenile and adult seals were found. Lymphocytes from juveniles showed a higher susceptibility to the toxic e ect compared to lymphocytes from adults. Furthermore, the degree of inhibition of proliferation varied among the four Hg compounds. The organic compounds seem to be more immunotoxic than the inorganic compound. Finally, for the cytokine expression of methylmercury-incubated lymphocytes, timedependent changes were observed, but no dose-dependency was found. Marine mammals of the North Sea are burdened with Hg, and lymphocytes of harbor seals may be functionally impaired by this metal. The present in vitro study provides baseline information for future studies on the immunotoxic e ects of Hg on cellular immunity of harbor seals.