晃动平台下ADCP测流误差分析与校正

测量不稳定流和受潮汐影响的流量一直是水文工作者所面临的难题。对于工作在海水中的走航式ADCP(声学多普勒流速剖面仪),在测量流速时,受风浪影响,往往引起测量平台的晃动,通过外接光纤陀螺,对平台的姿态进行修正,从而提高ADCP的测量精度。针对典型四波束ADCP建立了在考虑到平台晃动情况下的误差修正模型,仿真结果表明该方法可明显提高测流精度。     

寺家庄井田煤储层渗透率表征方法优选

煤储层渗透率是影响瓦斯抽采与煤层气开发的重要参数,快速评价不同结构煤体的渗透率对指导现场工作有重要意义。以寺家庄井田为例,为了优选出表征煤储层渗透率的合适方法,通过裂隙分形维数、声波速度和地质强度指标(GSI)对煤体结构进行定量表征,测试其渗透率,依据表征的难易程度和二者拟合系数进行对比。结果表明:裂隙分形维数与渗透率相关性显著,但是操作较为繁琐且不适用于软煤;声波速度法操作简单,但与渗透率关系不明显;地质强度指标与渗透率具有显著的相关性,操作简单,适用于所有煤体结构。因此,寺家庄井田煤储层渗透率表征的最佳方法为地质强度指标法。     

忻州窑煤矿5931巷道卸压槽防冲模拟与试验研究

采用理论分析、数值模拟与现场试验相结合的方法,对忻州窑煤矿5931巷道卸压槽防冲效果进行研究.数学推导了巷道底板岩层轴向力,分析了巷道底鼓原因.根据煤岩体静载破坏理论,确定了巷道卸压槽防冲技术方案.并运用FLAC3D数值软件模拟布置卸压槽巷道围岩应力、变形状态,从模拟结果可以看出,卸压槽具有很好的防冲作用.最后,选取部分5931巷道开展卸压槽防冲试验,布槽巷道围岩变形量明显减小,与模拟结果较为一致,同时,声发射现象显著减弱,证实卸压槽有好的防冲效果.     

气体管道中阀门内漏声发射信号特性研究

针对石化企业气体阀门内漏在线诊断问题,设计并建立气体截止阀内漏检测实验装置,根据声发射技术理论与实验相结合研究截止阀内漏特性,对比不同压差下信号参数分布规律。结果表明,阀门泄漏率与信号振幅和平均信号电平ASL均呈指数分布,与能量和均方根AERMS呈对数分布,并拟合了泄漏率与AERMS的函数关系式。因此,可以综合各对应关系对阀门是否泄漏进行检测,并利用泄漏率与AERMS的函数关系式定量估算阀门泄漏率。     

热析-混凝-气浮工艺处理胶管废水工程实践

基于废水中的污染物在热态、碱性和一定硬度的情况下,从水中析出的特点,探究了温度、pH和硬度对处理效果的影响。在此基础上,提出了热析+混凝+气浮处理工艺,并进行了设计和调试。实际运行结果表明,在水温在65～70℃、出水pH值在7.5～8.5和MgSO4用量在40～65 mg/L范围内的情况下,对析出的污染物进行混凝,再经过涡凹气浮对高温废水中的絮体稳定、高效的分离,CODCr和TP的最低去除率分别为89.4%和90.3%,各项指标完全达到设计要求。     

Use of recycled natural fibres in industrial products: A comparative LCA case study on acoustic components in the Brazilian automotive sector

This paper summarizes the results and the lessons learnt from an LCA case study comparing acoustic automotive components. Three alternative acoustic components produced by the Brazilian automotive sector are considered: dual-layer polyurethane (DL-PU) panel, recycled textile absorption-barrier-absorption (ABA-cotton) panel and recycled textile DL (DL-cotton) panel. DL-PU is a “status-quo” alternative, composed mainly of synthetic plastics and the two other alternatives are mainly made of recycled cotton fibres. Using the Life Cycle Assessment (LCA) method, the three following phases of the panels’ life cycle are examined: production, use and end-of-life. For the latter, two end-of-life scenarios are analysed: landfill and incineration with energy recovery. For the LCA model, some Life Cycle Inventory (LCI) datasets have been adapted from the data available in the EcoInvent database in order to adjust to the Brazilian context. LCA results show that, within the entire life cycle, the DL-cotton option, which combines two layers of recycled fibres of different densities, is overall the best alternative from an environmental perspective. This result is therefore independent from the end-of-life scenario. This is mainly due to the lower weight of this component, which is extremely important for the transportation aspects, but also due to its lower consumption of fossil resources, to the energy saving during its production and to the avoidance of textile disposal that would happen otherwise. The obtained results confirm the available literature dealing with the use of renewable fibres in industrial products. The particular behaviour of recycled fibres compared to virgin ones (in terms of shared contribution of agricultural production and of avoidance of landfilling) is highlighted in this paper, thanks to the application of the “50/50” allocation rule. LCA results are discussed in terms of their potential use in an R&D context. Further research needs are also derived from the case study, including the potential benefits of developing multi-objective optimization methods that include environmental impact to be used in the design of such a component.     

Pooled Analysis of Two Swedish Case-Control Studies on the Use of Mobile and Cordless Telephones and the Risk of Brain Tumours Diagnosed During 1997–2003

Here we present the pooled analysis of 2 case–control studies on the association of brain tumours with mobile phone use. Use of analogue cellular phones increased the risk for acoustic neuroma by 5%, 95% confidence interval (CI) = 2-9% per 100 hrs of use. The risk increased for astrocytoma grade III—IV with latency period with highest estimates using >10-year time period from first use of these phone types. The risk increased per one year of use of analogue phones by 10%, 95% CI = 6-14%, digital phones by 11%, 95% CI = 6-16%, and cordless phones by 8%, 95% CI = 5-12%. For all studied phone types OR for brain tumours, mainly acoustic neuroma and malignant brain tumours, increased with latency period, especially for astrocytoma grade III—IV.     

超声空化降解水中有机污染物的研究进展(续)

(接 2 0 0 2年第 5期 )3　影响超声降解的因素3.1　超声场超声场主要是指超声频率和声能强度。3.1.1　超声频率超声频率效应的研究是超声降解有机物的一个重要内容。这方面的文献较多 ,但对频率效应的认识不太一致。Ｐｅｔｒｉｅｒ和Ｆｒａｎｃｏｎｙ[2 0 ] 认为 ,随着超声频率的增大 ,超声空化阈值明显增大 ,空化过程变得难以进行 ;当超声声强超过空化阈值时 ,不同频率的超声均能产生相同的效果。Ｗｉｔｅｋｏｗａ等[4 5] 发现 ,超声频率对在水溶液中发生的氧化还原反应效果影响甚微。Ｃｕｍ等[4 6 ] 考察 2 0～ 10 0ｋＨｚ范围内的超声频…     

含酚废水的超声降解研究进展

超声处理污水技术是一项新兴的颇有发展前途的水处理技术，本文论述了超声降解含酚废水的反应机理，特点和影响因素，并对该技术在处理含酚类废水治理中存在的问题和今后的发展趋势进行了讨论。     

官渡区声学环境质量的调查研究

为调查城市声学环境质量，官渡区环境监测站在本区内设置了２４６个定期噪声监测点，并把监测的重点放在关上地区和金马地区这两个区域内，定期在两个区域内做了功能区噪声、环境噪声、道路交通噪声和其他选择项目的监测工作，根据监测结果，官渡区范围内的噪声源主要来源于交通、施工和生活，与国家城市区域环境噪声标准ＧＢ３０９６－８２比较，其声学环境质量还是好的。