热环境中透气式防护服的舒适性评价指标研究

本文依据热环境下人体穿着透气式防护服的散热形式以及舒适性要求,提出了热环境下透气式防护服舒适性评价指标,为热环境下透气式防护服舒适性评价提供了依据。     

Implementing real-time grouping for fast egress in emergency

Mass events such as the Olympic games or popular entertainment gathering often attract hundreds of thousands of people. If an abrupt event (e.g., fire, bomb threat) prompts people to rush to exits, stampedes may occur, creating secondary damages. Thus quickly dispersing crowd population to safe places in the least time while managing to avoid congestion and/or stampede is an important task with the occurrence of such events. This study presents an optimal evacuation model to meet this goal. By identifying some key themes that contribute to crowd disasters, the model implements a real-time concurrent grouping to ensure at-risk people are guided to safe places in the least time. The underlying rationale of the strategy is to advocate that competition should be replaced with coherence, and people should coordinate and collaborate to move out in an orderly way through scientifically using multiple routes. In doing so, each person receives an equal opportunity to exit the incident site, and the general effectiveness of performing an evacuation is achieved to an optimal level.To verify the proposed method, we conduct a simulation in which we compare our method with two benchmark cases: random self-evacuation and herding behavior. The results demonstrate that the proposed strategy can rescue people at risk much faster and more safely than two benchmark cases. We implement the proposed model through a web-based wireless decision support system, which provides a useful tool to both first responders and people affected for time-based crowd management in response to an ongoing crowd incident.     

中国城市污泥重金属区域分布特征及变化趋势

通过整理和统计国内外文献(2006—2013年)报道的中国城市污泥重金属含量,分析了近年来中国城市污泥重金属的区域分布特征和变化趋势.结果表明,城市污泥重金属Cu、Pb、Zn、Cd、Hg、As、Cr和Ni含量分别为182.5、65.3、729.6、2.1、1.4、11.5、97.5和44.9 mg·kg-1,与《城镇污水处理厂污染物排放标准》(GB18918-2002)规定的中碱性土壤污泥农用污染物控制标准限值比较,Cu、Pb、Zn、Cd、Hg、As、Cr和Ni的超标率分别为2.3%、0、5.9%、5.5%、2.9%、0、0和3.5%;与酸性土壤污泥农用污染物控制标准限值比较,Cu、Pb、Zn、Cd、Hg、As、Cr和Ni的超标率分别为7.1%、1.3%、10.3%、27.4%、20.0%、0、1.6%和12.1%.不同区域城市污泥重金属含量存在一定差异,城市污泥Hg和As在北方地区含量较高,而Cu、Pb、Zn、Cd、Cr和Ni在南方地区含量较高.与2006年城市污泥重金属含量相比,本研究城市污泥重金属Cu、Pb、Zn、Cd、Hg、As、Cr和Ni含量均呈下降趋势,降幅分别为29.0%、16.5%、40.9%、9.0%、29.8%、41.8%、5.3%和23.6%.     

江西省某冶炼厂遗留尾砂场重金属污染特征

以江西省某冶炼厂生产过程中遗留在厂内各尾砂池中的废渣为研究对象,利用单因子污染指数法和内梅罗综合污染指数法相结合的方法对其重金属污染状况进行评价。结果表明:各尾砂池土壤中铜、锌、镍、砷超标倍数高,且除尾砂池2深层土壤外,其他样点重金属内梅罗综合污染指数均远大于1,显示各尾砂池土壤均为重污染土壤。     

再生水—土壤—蔬菜体系中Zn的迁移

2011~2013年通过小区试验种植小白菜和萝卜,以再生水灌溉和污泥施肥,采用修正的BCR法测定了再生水、污泥、土壤、蔬菜中Zn的5种形态含量,分析Zn在再生水(污泥)-土壤-蔬菜体系中的迁移和累积特征。结果表明:2011~2013年水样中Zn含量均未超出国家《农田灌溉水质标准(GB5084—2005)》中Zn的标准。水样中水溶态B0比例较大。污泥中B0含量极少,残渣态B4含量较高。土壤中Zn的本底含量较少,经过3年的蔬菜种植和灌溉,土壤中Zn含量有增高的趋势。蔬菜中5种形态均有分布,地上部分中水溶态B0和可氧化态B3含量较高,地下部分中残渣态B4含量也较高。小白菜中Zn的含量高于萝卜。灌溉水中B0的含量对Zn在土壤和蔬菜中的迁移产生了较大影响。适当的再生水灌溉和污泥施肥可以改善土壤的缺Zn状况。     

灰场包气带环境影响预测方法研究——以新疆某电厂灰场为例

灰场在防渗不当或事故工况下,淋滤液的渗漏可能会对灰场包气带产生影响。以新疆某火电厂灰场的淋滤液渗漏情景为例,介绍了淋滤液渗漏对包气带影响的3种预测方法并进行对比分析。结果表明,两类解析法计算误差较大且存在各自适用条件,应优先采用数值法进行定量化预测。     

低强度超声波强化低温SMBR脱氮的性能与机制研究

考察了低温条件下低强度超声波对SMBR脱氮的强化作用,并研究了对硝化细菌脱氢酶活性和细胞通透性的影响。结果表明,经超声波强化后,SMBR对NH3-N5的去除效果得到明显提高,总去除率由启动完成时的65.94%升至84.01%,且长期运行稳定,说明超声波解除了低温对硝化作用的抑制。0.28 W/L超声波辐照20 min,可使硝化细菌脱氢酶活性提高81.19%,0.14 W/L的超声波辐照10 min使脱氢酶活性提高43.18%。0.28 W/L的超声功率密度对脱氢酶的活性提高程度最大,因此是较合适的超声波参数。     

Level and characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans in feed and feed additives

Feed security is a prerequisite for safe animal food products. In this study, 13 groups of feed and feed ingredients, totaling 2067 samples, were collected in the period of 2011 to 2014 from China. The highest mean level of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was found in fish meals and shell powders, with a concentration of 60.35 ng/kg, followed by mineral origin materials. In terms of the toxicity equivalent concentration, the fish oil group showed the highest PCDD/F levels because of their bio-accumulation through the aquatic food chain, with an average concentration of 1.26 ng WHO-TEQ/kg, while the lowest level was observed in compound feed for chickens and pigs, with an average value of 0.16 ng WHO-TEQ/kg. OCDD and OCDF were the predominant congeners in all groups except fish oils, in which the primary congeners were 2,3,4,7,8-PeCDF and 2,3,7,8-TCDF. For zinc chloride samples, different from other zinc-based compound samples, the main congeners were 1,2,3,4,6,7,8-HpCDF (17%), 1,2,3,4,7,8,9-HpCDF (15%), 1,2,3,4,7,8-HxCDF (12%) and OCDF (30%). Considering toxicity equivalency factors, the dominant congeners were 2,3,4,7,8-PeCDF, 1, 2,3,4,7,8-HxCDF, 2,3,7,8-TCDF and 1,2,3,7,8-PeCDD, and the contribution to the total TEQ was 29%, 16%, 14% and 12%, respectively. Overall, 2.1% (43 out of 2067) of all the analyzed samples exceeded the different individual ''European Union maximum limited levels for PCDD/Fs. This study is beneficial for the determination of the status of contamination levels of feed and feed ingredients.     

Photoelectrochemical performance of birnessite films and photoelectrocatalytic activity toward oxidation of phenol

Birnessite films on fluorine-doped tin oxide(FTO) coated glass were prepared by cathodic reduction of aqueous KMnO_4. The deposited birnessite films were characterized with X-ray diffraction, Raman spectroscopy, scanning electron microscopy and atomic force microscopy.The photoelectrochemical activity of birnessite films was investigated and a remarkable photocurrent in response to visible light was observed in the presence of phenol, resulting from localized manganese d–d transitions. Based on this result, the photoelectrocatalytic oxidation of phenol was investigated. Compared with phenol degradation by the electrochemical oxidation process or photocatalysis separately, a synergetic photoelectrocatalytic degradation effect was observed in the presence of the birnessite film coated FTO electrode.Photoelectrocatalytic degradation ratios were influenced by film thickness and initial phenol concentrations. Phenol degradation with the thinnest birnessite film and initial phenol concentration of 10 mg/L showed the highest efficiency of 91.4% after 8 hr. Meanwhile, the kinetics of phenol removal was fit well by the pseudofirst-order kinetic model.     

贵州找水工程高氟地下水分布特征及成因分析

通过对贵州省2007~2012年找水工程中所钻1 023口机井的水质资料收集分析可知:有34口机井的氟含量超标(1.02~3.72 mg/L)。本文以这34口机井为研究对象,从地理位置、地形地貌、地层岩性、涌水量、地下水类型等方面分析机井高氟地下水分布特征,并对其成因进行探讨,重点分析其水化学特征,对F-与其他组分进行相关性分析表明:其大致表现出F--Ca2+、F--SO42-、F--(总硬度-总碱度)、F--Ca2+/(K++Na+)彼此的正相关关系,与pH有关,而与其他离子的关系不明显。