列车引发地面振动的现场测试及数值分析

通过现场测试,对提速列车引发的铁路线附近地面振动的时域特性、频域特性、传播规律及其影响因素进行了研究,并利用有限元软件ANSYS建立了大地振动三维有限元模型对提速列车引发的地面振动进行了数值分析.结果表明,列车引发的地面振动属于低频振动,地面对高频振动具有衰减作用;地面振动随距轨道中心线距离的增大呈递减分布,并且与车速和机车牵引类型有关,地面的竖向振动大于横向振动l地面振动随列车速度的提高而增大,随列车轴重的增加而增大.     

无碴轨列车运行引起的环境振动影响评价

对遂渝高速铁路无碴轨道试验段客车运行引起的环境振动进行了现场实测,根据实验数据分析得知:环境振动强度随距离增大而减小,随车速增大而增大,但车厢数量对环境振动强度影响不明显;环境振动主要频率范围为30～120 Hz,距轨道距离、车速、车厢数量对振动主要频率影响不显著;在轨道两侧31.9 m处,速度超过104.7 km/h列车环境振动强度超过GB 10070-1988要求,须采取措施隔振。     

地铁轨道结构减振效果的实测分析

通过现场实测,研究地铁运行时不同轨道结构的振动特性及减振效果.通过频域分析得到地铁轨道结构的振动情况.结果表明,地铁诱发的振动的垂向加速度总振级比横向加速度总振级大很多,不同的轨道结构从道床到隧道壁的振动衰减有很大不同,因此评价轨道结构的减振效果应主要以隧道壁的垂向振动为主；浮置板轨道的固有频率约为10 Hz,属于低频...     

高速铁路动车组列车的噪声特性

测量了车速达250 km/h的高速铁路动车组列车不同距离、不同高度处的噪声,分析了其时间、频谱及空间分布特性,并与普通客运列车比较.结果表明,动车组列车噪声表现为较强的脉冲性,频谱较宽,为2 500 Hz内的宽频噪声,200 Hz以下的低频成分很强;不同高度处最大声压级随距离的衰减规律基本类似,但不同高度处频谱不同.     

实际工况下内河航行船舶NO_x排放测试与分析

为获得NO_x的排放特征,利用便携式排放测试系统(PEMS)对7艘京杭运河中航行的内河船舶进行了实际工况下的排放测试。测量结果表明:进、离港工况下NO和NO_2的浓度波动明显,而在巡航工况下NO浓度保持稳定且处于较高的排放水平。巡航工况下NO的基于时间的平均排放因子分别是进港和离港工况排放因子的3.22倍和1.74倍。而NO_2离港工况下的平均排放因子分别是巡航工况和进港工况下的平均排放因子1.18倍和1.96倍。受到航行距离的影响,进港工况下NO和NO_2基于距离的平均排放因子高于其他2个工况下的排放因子。当发动机处于高转速时,NO的排放因子最高,而NO_2则在中转速下的排放因子最高。     

超声预处理对剩余污泥酶活性的影响

为了研究不同工况下超声波预处理对剩余污泥酶活性变化的影响,对剩余污泥进行不同输入能量、频率的超声预处理,测定了预处理后污泥蛋白酶和脱氢酶的变化规律。结果表明:1)超声预处理在低能量输入条件下对污泥蛋白酶和脱氢酶活性存在促进作用,而随着超声能量的进一步增加,酶活性逐渐降低直至出现抑制现象;2)超声频率对污泥酶活性影响较为显著,其中20 k Hz超声频率对蛋白酶和脱氢酶活性的促进效果最高,其次分别为25和33 k Hz;3)当输入能量高于8000 k J·(kg TS)~(-1)后,25和33 k Hz频率超声预处理对污泥蛋白酶和脱氢酶活性存在抑制效应,引起该现象的原因分析可能是高频超声空化现象及伴随的热化学效应引起的生物酶失活导致的。     

在用汽油车简易测试工况排放特性研究

通过实验方法对在用汽油车在稳态ASM测试工况、IG195瞬态测试工况下的排放特性进行了研究，并与双怠速、怠速测试工况下的排放测试结果进行了比较。分析了车龄与排放的关系、发动机燃油供给方式与排放及与排放测试方法的关系，研究了排放因子与车龄的关系。     

隔振沟对强夯振动衰减的影响研究

研究了某海堤公路采用夯击法加固公路路基对海堤的振动影响。探讨了不同距离、不同夯击能量、有无隔振沟、不同隔振沟深度情况下夯击振动对海堤坝体的影响和传播规律。结果表明,隔振沟对于表面波的振动加速度有较大的衰减作用,而对于垂直方向的振动衰减不大,复打振动影响较大,隔振沟的深度对隔振效果有明显影响。最后,给出了不同夯击能量下的距离-振幅经验公式。     

房地产开发地铁振动达标距离研究

已建和待建的多条地铁线路穿过某房地产开发地块,为了防治地铁运行对建筑造成振动环境影响,需要设定建筑靠近地铁的最小达标距离,包括采取减振措施后的距离。通过现场系统实验监测结合数值模型分析,从工程实践的角度提出了上述距离。对于实验中观察到随距离出现振动局部放大以及进口与国产仪器监测结果不同的现象,佐证了有关学者的理论与实验分析,提出:(1)现有地铁环境影响评价报告常用的60m评价范围偏小,推荐可扩大至80~100m;(2)迫切需要新的振动环境标准发布,避免有关项目的环境管理要求偏低。     

环境微振技术呵护文物古迹

我国国家高技术应用发展项目——工业环境振动对文物古迹的影响及相应规范研究成果 ,最近通过了国家鉴定。参加鉴定的专家认为 ,该项技术达到了国际领先水平。工业环境振动对文物古迹 (殿堂类、古塔类、石窟类 )影响的研究 ,是一个全新、跨学科、难度很大的课题。 3年来 ,承担该项目的中国兵器工业第五设计研究院防微振研究所在著名防微振、环境振动和土动力专家潘复兰同志的主持下 ,对不同年代、不同类型的古建筑进行了大量的测试、分析、研究工作。通过将工业震源、古建筑结构的动力特性、模态分析技术、建筑结构的受力现状、震源与古建筑…     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

A History of Dry Cleaners and Sources of Solvent Releases from Dry Cleaning Equipment

Approximately 25, 000-35, 000 dry cleaning facilities currently operate in the U.S. The release of perchloroethylene and other solvents from these establishments represents a major source of soil and groundwater contamination. The manner in which dry cleaning solvents escape from dry cleaning plants is, for all practical purposes, identical for chlorinated and petroleum hydrocarbon solvents and is related to one of the following events: the catastrophic failure of a component of the dry cleaning system, the improper installation, operation or maintenance of the dry cleaning equipment or a combination of all of these causes. Acceptable customs, codes and regulations can also dictate what is authorized for operation of a dry cleaning facility in a particular community, geographic area during a particular time frame. Environmental litigation dealing with the origin of a solvent release from dry cleaners tends to focus on the design and manufacture of dry cleaning industry machines such as washers, washer extractors, tumblers, solvent filters, water separators, stills and spotting boards. A thorough analysis of the daily operations of dry cleaners often reveals that poor maintenance, failure to follow the manufacturer's instructions and the actions of the operator are the most likely causes of soil and groundwater pollution. In order to forensically evaluate the most probable origins of a solvent release and to examine issues regarding liability, a thorough understanding of the history of dry cleaning and a detailed analysis of the operation and maintenance of the dry cleaning equipment are necessary. The discovery of solvent plumes in the vicinity of dry cleaning plants may suggest that the solvent source is the dry cleaning plant; however, the presence of these plumes does not necessarily indicate that the dry cleaning equipment was defectively designed or manufactured. A thorough review of the type of equipment used over the life of the dry cleaning plant and verifiable solvent mileage records frequently indicates that operators of the plant have disposed of solvent and contaminated solids into the municipal sewer or on ground surfaces.     

Radionuclides and trace elements in fish collected upstream and downstream of Los Alamos national laboratory and the doses to humans from the consumption of muscle and bone

Abstract

The purpose of this study was to determine radionuclide and trace element concentrations in bottom‐feeding fish (catfish, carp, and suckers) collected from the confluences of some of the major canyons that cross Los Alamos National Laboratory (LANL) lands with the Rio Grande (RG) and the potential radiological doses from the ingestion of these fish. Samples of muscle and bone (and viscera in some cases) were analyzed for ³H, ⁹⁰Sr, ¹³⁷Cs, ^totU, ²³⁸Pu, ^239,240Pu, and ²⁴¹Am and Ag, As, Ba, Be, Cr, Cd, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Most radionuclides, with the exception of ⁹⁰Sr, in the muscle plus bone portions of fish collected from LANL canyons/RG were not significantly (p<0.05) higher from fish collected upstream (San Ildefonso/background) of LANL. Strontium‐90 in fish muscle plus bone tissue significantly (p<0.05) increases in concentration starting from Los Alamos Canyon, the most upstream confluence (fish contained 3.4E‐02 pCi g^‐1 [126E‐02 Bq kg^‐1]), to Frijoles Canyon, the most downstream confluence (fish contained 14E‐02 pCi g^‐1 [518E‐02 Bq kg^‐1]). The differences in ⁹⁰Sr concentrations in fish collected downstream and upstream (background) of LANL, however, were very small. Based on the average concentrations (±2SD) of radionuclides in fish tissue from the four LANL confluences, the committed effective dose equivalent from the ingestion of 46 lb (21 kg) (maximum ingestion rate per person per year) of fish muscle plus bone, after the subtraction of background, was 0.1 ± 0.1 mrem y^‐1 (1.0 ± 1.0 μSv y^‐1), and was far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem y^‐1 (1000 μSv y^‐1). Of the trace elements that were found above the limits of detection (Ba, Cu, and Hg) in fish muscle collected from the confluences of canyons that cross LANL and the RG, none were in significantly higher (p<0.05) concentrations than in muscle of fish collected from background locations.     

Malathion-induced sublethal toxicity on the intestine of cricket frog (Fejervarya limnocharis)

The effect of malathion [diethyl(dimethoxythiophosphorylthio)succinate] at sublethal concentration (0.006 ppm) on intestinal parameters of cricket frog (Fejervarya limnocharis) was studied for 24 hrs to 240 hrs of exposure and remarkable histopathological alterations were observed. The study on intestinal parameters revealed acute pathological conditions in the intestinal wall. The toxic effect became evident as the cytoplasm of the cells disintegrated and the cells became empty and vacuolated. The cell membranes were also ruptured. Degenerative changes of the absorptive surface (villi) of the intestine in the different periods of exposure were pronounced. Severe atrophic nature (necrotic mucosa) of the intestine began from 48 hrs onwards to 96 hrs of exposure.     

Radionuclides in deer and elk from Los Alamos national laboratory and the doses to humans from the ingestion of muscle and bone

Abstract

This paper summarizes radionuclide concentrations (³H, ⁹⁰Sr, ¹³⁷Cs, ²³⁸Pu, ^239,240Pu, ²⁴¹Am, and ^totU) in muscle and bone tissue of mule deer (Odocoileus hemionus) and Rocky Mountain elk (Cervus elaphus) collected from Los Alamos National Laboratory (LANL), Los Alamos, New Mexico, lands from 1991 through 1998. Also, the committed effective dose equivalent (CEDE) and the risk of excess cancer fatalities (RECF) to people who ingest muscle and bone from deer and elk collected from LANL lands were estimated. Most radionuclide concentrations in muscle and bone from individual deer (n = 11) and elk (n = 22) collected from LANL lands were either at less than detectable quantities (where the analytical result was smaller than two counting uncertainties) and/or within upper (95%) level background (BG) concentrations. As a group, most radionuclides in muscle and bone of deer and elk from LANL lands were not significantly higher (p<0.10) than in similar tissues from deer (n = 3) and elk (n = 7) collected from BG locations. Also, elk that had been radio collared and tracked for two years and spent an average time of 50% on LANL lands were not significantly different in most radionuclides from road kill elk that have been collected as part of the environmental surveillance program. Overall, the upper (95%) level net CEDEs (the CEDE plus two sigma for each radioisotope minus background) at the most conservative ingestion rate (50 lbs of muscle and 13 lbs of bone) were as follows: deer muscle = 0.22 mrem y^‐1 (2.2 μSv y^‐1), deer bone = 3.8 mrem y^‐1 (38 μSv y^‐1), elk muscle = 0.12 mrem y^‐1 (1.2 μSv y^‐1), and elk bone = 1.7 mrem y^‐1 (17 μSv y^‐1). All CEDEs were far below the International Commission on Radiological Protection guideline of 100 mrem y^‐1 (1000 μSv y^‐1), and the highest muscle plus bone net CEDE corresponded to a RECF of 2E‐06, which is far below the Environmental Protection Agency upper level guideline of 1E‐04.     

Nitrogen leaching and acidification during 19 years of NH₄NO₃ additions to a coniferous-forested catchment at Gårdsjön, Sweden (NITREX)

The role of nitrogen (N) in acidification of soil and water has become relatively more important as the deposition of sulphur has decreased. Starting in 1991, we have conducted a whole-catchment experiment with N addition at Gårdsjön, Sweden, to investigate the risk of N saturation. We have added 41 kg N ha⁻¹ yr⁻¹ as NH₄NO₃ to the ambient 9 kg N ha⁻¹ yr⁻¹ in fortnightly doses by means of sprinkling system. The fraction of input N lost to runoff has increased from 0% to 10%. Increased concentrations of NO₃ in runoff partially offset the decreasing concentrations of SO₄ and slowed ecosystem recovery from acid deposition. From 1990-2002, about 5% of the total N input went to runoff, 44% to biomass, and the remaining 51% to soil. The soil N pool increased by 5%. N deposition enhanced carbon (C) sequestration at a mean C/N ratio of 42-59 g g⁻¹.     

Leaching of seven pesticides currently used in cotton crop in Mato Grosso State—Brazil

This study aimed to evaluate the leaching of pesticides and the applicability of the Attenuation Factor (AF) Model to predict their leaching. The leaching of carbofuran, carbendazim, diuron, metolachlor, α and β endosulfan and chlorpyrifos was studied in an Oxisol using a field experiment lysimeter located in Dom Aquino – Mato Grosso. The samples of percolated water were collected by rain event and analyzed. Chemical and physical soil attributes were determined before pesticide application to the plots. The results showed that carbofuran was the pesticide that presented a higher leaching rate in the studied soil, so was the one representing the highest contamination potential. From the total carbofuran applied in the soil surface, around 6 % leached below 50 cm. The other pesticides showed lower mobility in the studied soil. The calculated values to AF were 7.06E-12 (carbendazim), 5.08E-03 (carbofuran), 3.12E-17 (diuron), 6.66E-345 (α-endosulfan), 1.47E-162 (β-endosulfan), 1.50E-06 (metolachlor), 3.51E-155 (chlorpyrifos). AF Model was useful to classify the pesticides' potential for contamination; however, that model underestimated pesticide leaching.     

Endosulfan in China 2—emissions and residues

Background, aim, and scope  Endosulfan is one of the organochlorine pesticides (OCPs) and also a candidate to be included in a group of new persistent organic pollutants (UNEP 2007). The first national endosulfan usage inventories in China with 1/4° longitude by 1/6° latitude resolution has been reported in an accompanying paper. In the second part of the paper, we compiled the gridded historical emissions and soil residues of endosulfan in China from the usage inventories. Based on the residue/emission data, gridded concentrations of endosulfan in Chinese soil and air have been calculated. These inventories will provide valuable data for the further study of endosulfan. Methods  Emission and residue of endosulfan were calculated from endosulfan usage by using a simplified gridded pesticide emission and residue model—SGPERM, which is an integrated modeling system combining mathematical model, database management system, and geographic information system. By using the emission and residue inventories, annual air and soil concentrations of endosulfan in each cell were determined. Results and discussion  Historical gridded emission and residue inventories of α- and β-endosulfan in agricultural soil in China with 1/4° longitude by 1/6° latitude resolution have been created. Total emissions were around 10,800 t, with α-endosulfan at 7,400 t and β-endosulfan at 3,400 t from 1994 to 2004. The highest residues were 140 t for α-endosulfan and 390 t for β-endosulfan, and the lowest residues were 0.7 t for α-endosulfan and 170 t for β-endosulfan in 2004 in Chinese agricultural soil where endosulfan was applied. Based on the emission and residue inventories, concentrations of α- and β-endosulfan in Chinese air and agricultural surface soil were also calculated for each grid cell. We have estimated annual averaged air concentrations and the annual minimum and maximum soil concentrations across China. The real concentrations will be different from season to season. Although our model does not consider the transport of the insecticide in the atmosphere, which could be very important in some areas during some special time, the estimated concentrations of endosulfan in Chinese air and soil derived from the endosulfan emission and residue inventories are in general consistent with the published monitoring data. Conclusions  To our knowledge, this work is the first inventory of this kind for endosulfan published on a national scale. Concentrations of the chemical in Chinese air and agricultural surface soil were calculated for each grid cell. Results show that the estimated concentrations of endosulfan in Chinese air and soil agree reasonably well with the monitoring data in general. Recommendations and perspectives  The gridded endosulfan emission/residue inventories and also the air and soil concentration inventories created in this study will be updated upon availability of new information, including usage and monitoring data. The establishment of these inventories for the OCP is important for both scientific communities and policy makers.