饮食业油烟道火灾事故概率的模糊事故树分析

根据常规事故树定量计算中基本事件概率的不确定性问题,通过引入模糊集的概念,将常规事故树中基本事件的发生概率模糊化,用三角形模糊数代替确定性发生概率,应用模糊数截集方法,推导了模糊事故树的相关算法.采用模糊事故树方法得到饮食业油烟道火灾事故发生概率,并进行了敏感性分析,找出对顶事件发生概率影响较大的基本事件,确认减小油烟道火灾事故发生的相关措施.研究表明,饮食业油烟道火灾事故概率的模糊事故树分析是切实可行的,有助于对饮食业油烟道火灾的认识、预防和扑救工作.     

安阳市大型工业区和周围社区土壤中重金属污染特征及健康风险评价

为了解安阳市大型工业区和周围社区表层土壤中重金属元素的分布特征和健康风险,用ICP-OES测定了样品中9种重金属元素的含量.结果 表明:Zn、Cu、Pb、Mn、As、Cd、Cr、Co和Ni在社区表层土壤中的平均浓度为71.0、25.6、43.2、548、118.4、0.71、59.5、18.8、24.5 mg/kg;在...     

舰载飞机腐蚀控制与防护技术

分析了舰载飞机高温、高湿、高盐雾的服役环境特点,并阐述了舰载飞机易发生的腐蚀问题,提出了舰载飞机腐蚀防护与控制的研究思路,并对舰载飞机先进腐蚀控制与防护技术进行了总结,包括结构防护设计、选用综合性能优良的耐蚀材料、防护技术、舰上腐蚀控制维护/维修技术等。总结了舰载飞机全面腐蚀控制研究重点发展方向及建议。     

Dioxin-like compounds in agricultural soils near e-waste recycling sites from Taizhou area, China: chemical and bioanalytical characterization

The crude recycling of electronic and electric waste (e-waste) is now creating a new set of environmental problems especially in developing countries such as China. The present study aimed to characterize the dioxin-like compounds in Taizhou area, one of the largest e-waste recycling centers in China, using both chemical analysis and in vitro bioassay. Agricultural soil samples were screened for aryl hydrocarbon receptor (AhR) activity with EROD bioassay in H4IIE cells, and the concentrations of the target AhR agonists including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) were determined by instruments. The bioassay-derived TCDD equivalents (TEQ(bio)) and the chemical-calculated TCDD equivalents (TEQ(cal)) were then compared, and mass balance analysis was conducted to identify the contributors of the observed response. Raw soil extracts from all locations induced significant AhR activities, where the TEQ(bio) ranged from 5.3 to 210 pg/g dry weight soil (pg/g dw). The total concentrations of 17 PCDD/Fs, 36 PCBs and 16 PAHs varied from 210 to 850 pg/g dw, 11 to 100 ng/g dw, and 330 to 20,000 ng/g dw, respectively. Profile characterization of the target analytes revealed that there were similar sources originating from the crude dismantling of electric power equipments and the open burning of e-waste. There was a significant relationship between TEQ(cal) and TEQ(bio) (r=0.99, p<0.05). Based on the mass balance analysis, PCDD/Fs, PCBs and PAHs could account for the observed AhR responses in vitro elicited by soil extracts, though their respective contributions varied depending on sample location. In this study, the combination of chemical analysis and bioanalytical measurements proved valuable for screening, identifying and prioritizing the causative agents within complex environmental matrices.     

污水厂污泥在亚/超临界丙酮中的液化行为

利用直接热化学液化技术,在1000mL的反应釜中,考察了液化温度、污泥/溶剂配比(R1)、催化剂以及溶剂填充率(R2)对污水厂污泥在亚/超临界丙酮中的液化行为的影响.结果表明,约300℃条件下,污泥液化较为彻底,过低或过高的温度液化效果反而较差.当温度超过340 ℃时,丙酮溶剂参与反应能力增强,促进油产率的增加,至380℃时油产率保持稳定.在其他液化条件相同的情况下,发现污泥在R1为10/200、R2为20%、添加5%剂量的NaOH作为催化剂,获得较好的液化效果.红外光谱(FTIR)和气相色谱/质谱分析(GC-MS)分析表明,生物油的主要成分是含氮杂环、羧酸、酯、酮等化合物,主要的官能团包括胺基、羟基、烷基和羰基等.     

人工湿地中抗生素抗性大肠杆菌和抗性基因的去除与分布

抗生素的滥用导致抗生素抗性菌和抗性基因随生活污水和养殖废水的排放在环境中肆意散播,其去除及环境行为越来越受到关注。采用K-B纸片法测定了9套不同工艺构型模拟人工湿地中大肠杆菌对7种抗生素的抗性率,并应用多重PCR检测磺胺类sul1、2、3与四环素tetA、B、C、D抗性基因,探究人工湿地对抗性菌的去除效率及抗性菌、抗性基因的分布规律。结果显示,人工湿地能有效去除污水中70%左右的抗性大肠杆菌,有效降低了细菌抗性的传播风险;共计分离出535株大肠肝菌中有378株对一种以上抗生素有抗性性,以四环素、磺胺类和氨苄西林抗性率最高,达到25%以上,其他4种抗性率较低,不足20%;2种抗性基因的检出率都在70%以上;对不同采样点大肠杆菌的抗性性及抗性基因的比较发现,各部分大肠杆菌的抗性水平、多重抗性指数(MRI)以及抗性基因(sul、tet)检出率和组合数表现出:基质≥出水>进水,推测抗性菌被湿地基质截留,在基质生物膜上发生抗性基因的重组,并释放抗性菌,提高了出水中抗性水平和抗性基因检出率。     

Effcient degradation of lube oil by a mixed bacterial consortium

A laboratory study was performed to assess the biodegradation of lube oil in bio-reactor with 304# stainless steel as a biofilm carrier. Among 164 oil degrading bacterial cultures isolated from oil contaminated soil samples, Commaonas acidovorans Px1, Bacillus sp. Px2, Pseudomonas sp. Px3 were selected to prepare a mixed consortium for the study based on the e ciency of lube oil utilization. The percentage of oil degraded by the mixed bacterial consortium decreased slightly from 99% to 97.2% as the concentration of lube oil was increased from 2000 to 10,000 mg/L. The degradation of TDOC (total dissolved organic carbon) showed a similar tendency compared with lube oil removal, which indicated that the intermediates in degradation process hardly accumulated. Selected mixed bacterial consortium showed their edge compared to activated sludge. Scanning electron microscopy (SEM) photos showed that biofilms on stainless steel were robust and with a dimensional framework constructed by EPS (extracellular polymeric substances), which could promote the biodegradation of hydrocarbons. The increase of biofilm followed first-order kinetics with rate of 0.216 g glucose/(cm2 day) in logarithm phase. With analysis of Fourier transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS) combined with removal of lube oil and TDOC, mixed bacterial consortium could degrade benzene and its derivatives, aromatic ring organic matters with a percentage over 97%.     

全氟辛烷磺酸盐(PFOS)对土壤跳虫的生态毒性

将两种跳虫(Folsomia candida和Folsomia fimearia)暴露在全氟辛烷磺酸盐(perfluorooctane sulfonate,PFOS)污染的人工土壤中,利用跳虫存活数量、繁殖数量与回避行为来评价PFOS对跳虫的生态毒性.结果表明,PFOS对F.candida和F.fimetaria急性毒性的LC50(7 d)分别为4 777和2 219 mg·kg-1,慢性毒性的EC50(28 d)分别为0.13和0.05 mg·kg-1.此外,PFOS对两种跳虫回避行为影响的EC50(48 h)分别为0.51 mg·kg-1(F.candida)和0.31 mg·kg-1(F     

基于改进差分进化算法优化极限学习机的短期负荷预测

负荷预测的精度直接关系到电网的供需平衡,影响着电网运营成本。针对传统预测方法精度不高的缺点,提出了一种改进的差分进化算法优化极限学习机的预测模型。由于极限学习机的输入权值和隐含层偏置对预测精度有很大影响,因而利用改进差分进化算法对极限学习机参数进行优化,提高了极限学习机的泛化能力和预测精度。研究结果表明:改进差分进化算法优化极限学习机对短期负荷预测精度有较高提升。     

为什么茅台镇的酒不等于茅台酒?

最近几年，市场上有一些白酒产品，利用“茅台”极高的市场信誉度和品牌价值，擅自以“茅台镇传世佳酿”、“茅台散酒”、“茅台某某酒”等相标榜，以致许多不了解情况的消费者被蒙蔽与误导，误认为是茅台酒的系列产品，与茅台酒是“一家人”。