Value-added utilisation of recycled concrete in hot-mix asphalt

The feasibility of partial substitution of granite aggregate in hot-mix asphalt (HMA) with waste concrete aggregate was investigated. Three hybrid HMA mixes incorporating substitutions of granite fillers/fines with 6%, 45% untreated, and 45% heat-treated concrete were evaluated by the Marshall mix design method; the optimum binder contents were found to be 5.3%, 6.5% and 7.0% of grade Pen 60/70 bitumen, respectively. All three hybrid mixes satisfied the Marshall criteria of the Singapore Land Transport Authority (LTA) W3B wearing course specification. The hybrid mix with 6% concrete fillers gave comparable resilient modulus and creep resistance as the conventional W3B mix, while hybrid mixes with higher concrete substitutions achieved better performance. X-ray diffraction (XRD) showed the distinct presence of free lime in the heat-treated concrete, while the scanning electron microscope (SEM) provided an in-depth perspective of the concrete grains in the HMA matrix. The results suggest feasible use of waste concrete as partial aggregate substitution in HMA.     

Monitoring of the Endangered Pinna nobilis Linné, 1758 in the Mar Grande of Taranto (Ionian Sea, Italy)

Two methods were used to calculate the meteorologically adjusted ground level ozone trends in southern Taiwan. The first method utilized is a robust linear regression method. The second approach uses a multilayer perceptron (MLP) artificial neural network (ANN) method. The observations obtained from 16 monitoring stations were analyzed and divided into six groups by hierarchical divisive clustering procedure. The daily maximum 1 and 8 h ozone concentrations for each group are then calculated. The meteorologically adjusted trends obtained by linear regression and MLP methods are smaller than the unadjusted trends for all groups and average time. It indicts that the meteorological conditions in Taiwan tend to increase ambient ozone concentrations in recent years.     

基于主成分分析法的安徽省生态环境质量研究

人类根据自身的具体要求可对生态环境质量进行评定。研究选择具有代表性、可比性、可操作性的评价指标,运用主成分分析法对安徽省17个地市的环境质量的优劣程度进行了定性、定量分析和判别,为安徽生态省建设和环境管理提供科学依据。     

Vertical ozone distributions observed using tethered ozonesondes in a coastal industrial city, Kaohsiung, in southern Taiwan

This work presents the vertical distributions of ozone and meteorological parameters observed with tethered ozonesondes and meteorological radiosondes in the lower atmosphere during an ozone episode on March 25–27, 2003, in Kaohsiung City in southern Taiwan. Kaohsiung is a coastal industrial city with inland mountain ranges to the east. Extremely complicated ozone structures were identified that spanned day and night during the experimental period. During afternoons, the lower atmosphere was divided into two stratified air layers with substantially different ozone concentrations. On the episode day (March 26), average ozone concentration in the near-ground layer was 85 ppb and the aloft layer was 140 ppb. A very high ozone peak of 199 ppb measured aloft likely resulted from an elevated large point source. Several no-ozone air layers, distributed throughout 400–750 m, were observed to transport onshore during the nigh. As well, elevated ozone layers peaking at 60–90 ppb and 90–160 ppb were detected below and above the no-ozone air layers, respectively. These complicated ozone structures were likely formed through titration of plumes from large point sources and the circulations of sea breezes or combined sea-breeze/mountain flows in the study area.     

Evaluating the dynamical characteristics of particle matter emissions in an open ore yard with industrial operation activities

A study to investigate the dynamical characteristics of particle matter emissions in a working open yard is conducted in Caofeidian Port of Hebei Province, China. The average diurnal concentrations of the total suspended particulate (TSP) matter and respirable particulate matter (PM₁₀ and PM₅) are monitored during the field measurement campaign. Sampling is performed at a regular interval at 8 monitoring stations in the yard with normal industrial activities. The average TSP, PM₁₀ and PM₅ concentrations range from 285 to 568, 198 to 423 and 189 to 330 μg.m-3 in the yard, respectively. The linear regression correlation coefficient of TSP/PM₁₀ and TSP/PM₅ is 0.95±0.01 and 0.88±0.02, respectively.By using the Spearman correlation method, the wind speed and relative humidity are both weakly correlated with the PM₁₀ and PM₅ concentrations according to the measurements. In addition, industrial operation activities, such as vehicular traffic in the yard and the loading time of stackers, are significantly positively correlated with the PM concentration. Using the multivariate regression method, the main parameters influencing the TSP concentration variations are integratedly analysed. The traffic volume is found to be a significant predictor of TSP concentration variation, with the smallest P value (P<0.05).To understand the dynamical characteristics of particle emissions in the yard, the emissions from the truck transports, that is, from unpaved haul roads and from the loading process, are established. Then, the dynamical emission factor (EF_D) based on the industrial activities in the yard is proposed. The dynamical emissions average 5.25x10⁵ kg.year^-1 and EF_D is evaluated to be 0.29 kg.(ton.day)^-1 during the measurement period. These outcomes have meaningful implications not only for understanding the dynamical characteristics of particle emissions in the working stockyard but also for implementing effective control measures at appropriate sites in the harbour area.     

特种方舱铁路运输异常调车纵向冲击试验研究

目的 针对特种方舱铁路运输,明确异常调车纵向冲击试验方法,并掌握异常纵向冲击安全性边界.方法 首先开展"一车冲一车"、"一车冲三车"铁路冲击对比试验,获得2种工况下的冲击特性数据.然后,基于冲击试验获得的缓冲器性能,建立特种方舱铁路运输调车作业动力学模型,研究冲击模式下不同冲击速度的纵向冲击特性.结果 试验工况1(冲击...     

海上油气爆燃事故虚拟仿真应急演练关键技术研究

基于海上平台火灾模拟演练需求,结合分布式虚拟仿真技术建立了一套交互式灾情应急演练系统。通过使用FDS软件模拟火灾温度场、CO浓度和火焰辐射条件,用MATLAB软件进行拟合和规律分析,UNITY软件进行数据模拟,可以准确模拟海上平台火灾险情和人为干预结果,有效解决实际演练缺少结果验证的弊端,降低应急演练成本,提高人员安全意识。     

麦穗鱼物种敏感性评价

分别进行了Cd、Cu对麦穗鱼和Cu对大型溞的急性毒性试验,结合麦穗鱼、大型溞的室内毒性试验数据和文献毒性数据,使用物种敏感性分布法对麦穗鱼的6种典型污染物的敏感性进行了对比分析.结果表明:①麦穗鱼对各类污染物的敏感性较高,尤其对有机污染物反应灵敏,其中对农药类相对最为敏感,表明麦穗鱼可以作为潜在的有机污染监测的指示生物和水质基准的代表性受试生物.②在鱼类敏感性排序中,鲤科鱼类对各类污染物的敏感性较强,而我国的鱼类以鲤科为主,因此在水质基准制定和环境监测中应充分考虑鲤科鱼类的作用及其毒性数据;③麦穗鱼在鱼类敏感性排序中位置稳定,并且具有体型小、易获得等特性,表明麦穗鱼是环境监测中较为理想的指示生物,同时也是潜在的水质基准受试生物.     

环境浓度双氯芬酸对活性污泥处理性能和微生物群落的影响

双氯芬酸(Diclofenac,DCF)是水环境中高频检出的新兴污染物,随着DCF的广泛使用,城市污水中的DCF逐年增加,对污水生物处理系统可能产生不利影响.本研究在序批式活性污泥反应器(SBR)中进行了连续120 d的DCF暴露实验,考察了环境浓度DCF(5和50μg·L~(-1))对SBR出水水质、微生物活性及微生物群落结构的影响.结果表明,DCF可降低COD的去除效果,但对氨氮和总氮的去除几乎没有影响.在微生物生理生化性能方面,5μg·L~(-1) DCF可促进超氧化物歧化酶(SOD)和琥珀酸脱氢酶(SDH)活性升高,但50μg·L~(-1) DCF导致SOD和SDH活性下降,DCF胁迫使胞外聚合物(EPS)含量增加.DCF会对微生物群落结构造成影响,其中,革兰氏阴性菌丰度增加,革兰氏阳性菌在5μg·L~(-1) DCF压力下丰度无明显变化,但在50μg·L~(-1) DCF压力下丰度显著降低(p0.05),微生物群落多样性在5μg·L~(-1) DCF下增加但在50μg·L~(-1) DCF下降低.16S rRNA基因焦磷酸测序结果表明,Proteobacteria是活性污泥群落中的优势门.随着DCF浓度的升高,Proteobacteria丰度不断增加,Chloroflexi、OD1和Firmicutes丰度则受到一定程度的抑制.高浓度DCF(50μg·L~(-1))刺激导致特定菌属如Nakamurella、Micropruina等丰度增加.研究结果揭示了环境浓度的DCF对活性污泥微生物处理能力和群落结构的影响特征,可为DCF的风险评估和污水处理工艺的优化提供借鉴.     

Characterization of coal burning-derived individual particles emitted from an experimental domestic stove

Coal combustion in the domestic stoves, which is common in most parts of the Chinese countryside, can release harmful substances into the air and cause health issues. In this study, particles emitted from laboratory stove combustion of the raw powder coals were analyzed for morphologies and chemical compositions by using transmission electron microscopy(TEM) coupled with energy-dispersive X-ray spectrometry(EDX). The coal burning-derived individual particles were classified into two groups: carbonaceous particles(including soot aggregates and organic particles) and non-carbonaceous particles(including sulfate, mineral and metal particles). The non-carbonaceous particles, which constituted a majority of the coal burning-derived emissions, were subdivided into Si-rich, S-rich, K-rich,Ca-rich, and Fe-rich particles according to the elemental compositions. The Si-rich, S-rich and K-rich particles are commonly observed in the coal burning emission. The proportions for particles of different types exhibit obvious coal-issue dependence. Burning of coal with high ash yield could emit more non-carbonaceous particles, and burning of coal with high sulfur content can emit more S-rich particles. By comparing the S-rich particles from this coal burning experiment with those in the atmosphere, we draw a conclusion that some S-rich particles in the atmosphere in China could be mainly sourced from coal combustion.