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。     

城市配电室噪声与振动控制分析

环境污染与治理一直是社会关注的热点问题,随着城市化进程快速发展,因城市规划与用地的限制,作为重要电力分配场所的配电室越来越多地安置于城市办公区或居民楼区内。配电室内变压器、风机等设备运行时会产生环境噪声污染。同时设备振动会通过地面以及建筑结构向外传播,不仅激发环境振动污染,而且还可能诱发二次结构噪声。面对日益增多的投诉与矛盾,对城市配电室所致噪声振动的产生机理、传播规律以及合理的降噪减振措施进行研究具有十分重要的意义。通过现场测试对配电室噪声振动及其传播特性进行分析,以一10 k V典型配电室为例,设计降噪减振的方案和措施,以期达到噪声振动达标排放,改善居民生活和居住环境的目的。     

消除噪音 为民除害

我厂位于市内居民集中地,锅炉房与居民住宅仅一墙之隔。锅炉配用的鼓、引风机所产生的噪声不仅影响了操作工人的身体健康,而且使周围居民无法正常休息与睡眠,居民意见很大,曾多次向市有关部门反映。为此,我厂于80年8月对锅炉房进行了噪声现场测试,并提出了治理方案。我厂锅炉房的一台KZG1-3型快装锅炉(1吨/小时),配用6—46#4,1750转/分鼓风机,和Y 4—70#5,2400转/分引风机各一台。经测试,工作机房噪声值为33dBA,而引起机房内噪声值达92dBA,影响到附近居民住房内噪声也竟达59dBA。特别是晚上,这样强的噪声使居民根本无法入睡。     

室内箱式变压器结构声污染及对策

通过对置于住宅楼底层室内箱式变压器引起的结构声污染进行调查实测，在对箱式变压器结构声传播进行声学分析基础上，提出了切实可行的防治对策，经实际工程应用验证，效果较好。对机房正上方住房主卧内降噪量为5.0dB，室内夜间噪声降为30.2dB，各层住户夜间烦恼度普遍从非常烦恼或烦恼降为有点烦恼和不大烦恼。这从噪声污染控制的角度证明了变配电房置于住宅楼等噪声敏感建筑物室内底层甚至更高楼层在技术上是可行性的。同时也为杭州市正在试点推广的箱式变压器置于噪声敏感建筑物底层提供了实践依据。     

电梯结构噪声分析和控制

文中根据民用电梯的一般结构布局,通过对声传播途径分析,得到电梯噪声扰民是受结构噪声影响的结论。通过对电梯系统和电梯与支架组成系统的力平衡分析,得出电梯结构噪声主要是主机支架设计不合理和安装不当产生的。文章提出了结构噪声防治措施,并对结构噪声扰民的多台电梯实施了工程控制措施,均取得了预期的降噪效果。     

供热系统水泵房噪声污染综合治理

通过对某石油勘探局公用事业处供热采暖系统热水泵房及毗邻楼层房屋的噪声和振动过大的机理分析 ,经综合考虑 ,提出了此水泵房噪声的治理方案。实际工程治理结果表明 ,在泵进出口处安装弹性接头、水泵底座下安放减振台和减振器、泵房采用隔声门和隔声窗对水泵房减振降噪效果令人满意。     

建筑施工噪声的监管与控制

在城市化进程加快的过程中,建筑施工产生的噪声如果不加以监管和防治,势必污染环境,影响居民的正常生活、工作与学习。建筑施工单位自身应使用低噪声的设备,改进施工方法,采取隔声、减噪等行之有效的措施,防治噪声污染,环保部门也要对其加强监管与指导,对违法施工、噪声超标排放的行为进行查处,以维护居民的合法权益不受侵害。     

从一起噪声扰民的民事案件谈居民的空调噪声标准

从一起邻里间空调噪声扰民的民事案件，阐述了居民邻里间空调扰民噪声监测方法及执行标准，从实践体会到，国家应制定更合适的噪声标准和测量方法，以利于处理这类问题。     

煤矿风井噪声控制技术

根据杨庄矿土型风井噪声的测试结果,分析了噪声产生的原因,对主声源实施了降噪治理.在对有关风井噪声综合治理的描述和研讨的基础上,希望提出科学有效的煤矿风井噪声治理措施.     

噪声污染不能成治污盲点

正假期想睡个好觉,没想到不容易:7:00不到,隔壁装修的电钻就开始"突突"拆墙;23:00开始,工程车、渣土车就轰轰地进隔壁小区施工了。居民想投诉这些扰民的噪声,也不容易。首先是向谁举报。《环境噪声污染防治法》规定,不同噪声归不同部门管理:工业噪声、建筑施工噪声归环保部门管;交通运输噪声、生活噪声,原则上归公安部门管。像笔者遇到的半夜装运施工垃圾的情形,到底属于建筑施工噪声还是交通运输噪声、     

室外大型空气压缩机的噪声治理技术

某室外安装的大型空气压缩机对环境造成了严重噪声污染,离机器2m远处噪声高达114 5dB(A)。在不允许停机的情况下,充分利用现场条件,采取了为空气压缩机加隔声罩、进气口滤清器加消声百页和管道作隔声包扎等综合治理措施,相应测点噪声已降至88 7dB(A),厂界噪声降至机器安装前背景值。室外机器的噪声控制方法与室内机器有许多不同,分析了这些差异并重点介绍了所设计的隔声罩在声学、通风、耐气候性和结构等方面的设计要点。     

控制居住区交通噪声的建筑措施

首先分析了交通噪声对居住区声环境的影响,然后重点探讨相应的防治方法,特别是在居住区的规划中,就利用对噪声不敏感的建筑物和绿化隔离带形成小区周边的声屏障、合理布置小区道路系统并防止城市交通穿越、加强住宅建筑设计中隔声构造处理等方面提出了具体的技术措施。     

Combined chemical and biological treatment of oil contaminated soil

Combined chemical (Fenton-like and ozonation) and biological treatment for the remediation of shale oil and transformer oil contaminated soil has been under study. Chemical treatment of shale oil and transformer oil adsorbed in peat resulted in lower contaminants' removal and required higher addition of chemicals than chemical treatment of contaminants in sand matrix. The acidic pH (3.0) conditions favoured Fenton-like oxidation of oil in soil. Nevertheless, it was concluded that remediation of contaminated soil using in situ Fenton-like treatment will be more feasible at natural soil pH. Both investigated chemical processes (Fenton-like and ozonation) allowed improving the subsequent biodegradability of oil. Moderate doses of chemical oxidants (hydrogen peroxide, ozone) should be applied in combination of chemical treatment (both, Fenton-like or ozonation) and biotreatment. For remediation of transformer oil and shale oil contaminated soil Fenton-like pre-treatment followed by biodegradation was found to be the most efficient.     

城市生活垃圾中转站举升装置设计与应用

对地平式城市垃圾中转站的 3种举升装置进行了详细分析 ,指出了其存在的问题 ,提出了一种新型的链条式城市垃圾中转站举升装置 ,它结构紧凑 ,运行平稳可靠 ,成本低 ,噪音小 ,节能省电 ,是垃圾中转站新型优选产品 ,现已成功应用于环卫工程中     

浙江省及杭州市电磁辐射环境污染源概况

介绍浙江省及省会城市杭州的电磁辐射环境污染源概况。浙江省现有各类污染源９３２４个，总功率４２４２ｋＷ；高压线（缆）５１３条，总长１１６０６ｋｍ；变电站３０４座；无轨电车３条。杭州市有各类污染源４２１０个，总功率２３６６ｋＷ；高压线（缆）８８条，长度１７２６ｋｍ；变电站５５座。分析了各类污染源的发展趋势。     

PCBs fires: Correlation of chlorobenzene isomer and PCB homolog contents of PCB fluids with PCDD and PCDF contents of soot

PCBs, PCDDs, and PCDFs are subject to new regulations promulgated under the Toxic Substances Control Act and the Resource Conservation and Recovery Act. The finding of PCDDs and PCDFs in PCBs could restrict disposal options for PCBs. A review of major fire incidents in the U.S., indicates that PCDDs have been found only in the Binghamton, N.Y., transformer fire incident. Laboratory combustion studies further support PCDFs formation from PCBs and PCDDs from chlorobenzenes. No PCDDs were found in analyses of fluids from transformers involved in transformer fire incidents. PCDFs do not appear to increase in PCBs askarel fluids from normal usage in electrical equipment.     

Monthly water quality forecasting and uncertainty assessment via bootstrapped wavelet neural networks under missing data for Harbin, China

In this paper, bootstrapped wavelet neural network (BWNN) was developed for predicting monthly ammonia nitrogen (NH⁴⁺–N) and dissolved oxygen (DO) in Harbin region, northeast of China. The Morlet wavelet basis function (WBF) was employed as a nonlinear activation function of traditional three-layer artificial neural network (ANN) structure. Prediction intervals (PI) were constructed according to the calculated uncertainties from the model structure and data noise. Performance of BWNN model was also compared with four different models: traditional ANN, WNN, bootstrapped ANN, and autoregressive integrated moving average model. The results showed that BWNN could handle the severely fluctuating and non-seasonal time series data of water quality, and it produced better performance than the other four models. The uncertainty from data noise was smaller than that from the model structure for NH⁴⁺–N; conversely, the uncertainty from data noise was larger for DO series. Besides, total uncertainties in the low-flow period were the biggest due to complicated processes during the freeze-up period of the Songhua River. Further, a data missing–refilling scheme was designed, and better performances of BWNNs for structural data missing (SD) were observed than incidental data missing (ID). For both ID and SD, temporal method was satisfactory for filling NH⁴⁺–N series, whereas spatial imputation was fit for DO series. This filling BWNN forecasting method was applied to other areas suffering “real” data missing, and the results demonstrated its efficiency. Thus, the methods introduced here will help managers to obtain informed decisions.     

快速高架复合道路近场交通噪声垂向分布

采用Cadna/A环境噪声模拟软件建立了高架复合道路的基本模型,根据6种基本模拟情况进行了声场模拟,并把模拟结果与实测结果进行对比分析。结果表明,高架道路结构本身对地面道路、高架道路分别形成的声场有明显的遮挡作用,但对高架复合道路所形成的声场遮挡作用不明显;对于高架复合道路垂向声场,在低层段地面道路的影响大于高架道路,而在高层段高架道路的影响起决定作用;高架复合道路较地面道路的垂向声场最大值增加2.5 dB(A),位置上移6m;在高架道路上设置声屏障有一定降噪效果,但在高架复合道路的上层设置声屏障降噪效果不理想。