活性炭吸附-微波催化氧化处理番茄酱加工有机废水

采用活性炭吸附-微波催化氧化技术处理番茄酱加工有机废水,考察了活性炭添加量、H2O2用量、辐射时间以及微波功率对废水处理效果的影响。确定微波催化氧化条件为:微波功率630w、辐射时间15min、H2O2用量0.9mL、活性碳用量1.5g/100mL。在此条件下对废水进行处理,废水的COD、TOC和BOD去除率分别为87.3%,84.4%和82.3%,处理时间由2h缩短为15min。结果表明,该方法是一种快速有效的处理番茄酱加工有机废水的方法。     

中国城市生活垃圾处理方法现状分析研究

城市生活垃圾无害化处理已成为重要的公共卫生问题。垃圾随意堆放会影响城市景观,而且占用土地;这是由于垃圾在堆放过程中由于在腐化过程中会产生大量酸性和碱性的有机污染物,这些污染物不仅污染环境并溶解出其中的重金属,对环境造成严重污染。本文分析了城市生活垃圾处理方法现状,阐述了将来的发展趋势,并针对目前中国城市垃圾处理存在的问题,提出了相关对策及工业化建议。     

城市景观河流水质污染防治进展研究

城市河流在维持城市发展中具有重要作用.城市河流的主要问题是由水质污染转变的生态退化或破坏,城市景观河流水质污染防治主要有物理、化学法、生物修复以及生态恢复法.针对不同的城市河流以及污染情况,需要用不同的污染防治措施,通过分析不同污染防治措施的原理及其应用特点,得出生物修复以及河水生态恢复效果明显且经济可行.并明确了目前城市河流污染防治的关键在于处理技术的创新及城市河流理念现代化.     

煤矿砂岩动态力学性能试验与分析方法研究

为研究动载荷作用下煤岩体测试与分析方法,基于直径50 mm分离式Hopkinson试验装置,采用半导体应变片和电阻应变片2种方法采集透射波,开展淮北矿区典型砂岩动态冲击压缩试验,采用二波法和三波法分别计算得到砂岩试件的应变率、应力和应变峰值等动态力学参数以及能量耗散特征,分析不同应变片种类和计算分析方法的差异性.结果表...     

自动化监控系统在许厂煤矿矿井水处理工程中的应用

介绍了许厂煤矿以工控机作为上位机,C200H系列PLC作为下位机,组态王6.5作为上位机监控软件以及模拟屏等组成的矿井水处理自动化监控系统,系统实现了整个工艺过程的全面监控以及处理工艺的关键环节,即自动加药和自动排泥.     

废水中KMnO4对生物处理效果的影响

为减轻和消除含高浓度KMnO4的牛仔服加工废水对生物处理系统的毒害作用,采用模拟序批式活性污泥法,研究KMnO4对活性污泥微生物生长的影响及COD和NH4+-N的降解规律。结果表明,当处理进水COD浓度500 mg/L,NH4+-N浓度23.5 mg/L,污泥浓度为2 000 mg/L时,曝气时间为4 h,KMnO4质量浓度增加对COD和NH4+-N的降解影响很大;同样条件下曝气时间改为8 h,对NH4+-N的降解影响显著减小,但对COD的降解影响减少不多;并且,高浓度KMnO4对NH4+-N去除效果的抑制作用比对COD的大。因此,处理含高浓度KMnO4的废水需要延长一倍曝气时间,可以获得良好的COD和NH4+-N的降解效果。同时,KMnO4对活性污泥的抑制影响较好地吻合非竞争性抑制机理修正莫若特方程的规律。     

Effect of processing on the disappearance of pesticide residues in fresh-cut lettuce: Bioavailability and dietary risk

The aim of this research is to establish the processing factors of six pesticides durong the preparation of fresh-cut lettuce and to assess the risk of ingestion of pesticide residues associated with the consumption of the same. A field study was carried out on the dissipation of three insecticides (imidacloprid, tebufenozide, cypermethrin) and three fungicides (metalaxyl, tebuconazole, azoxystrobin) during treatment conditions simulating those used for commercial fresh-cut lettuce. A simultaneous residue analysis method is validated using QuEChERS extraction with acetonitrile and CG-MS and LC-MS/MS analysis. The residues detected after field application never exceed the established Maximum Residue Limits. The processing factors were generally less than 1 (between 0.34 for tebufenozide and 0.53 for imidacloprid), indicating that the process, as a whole, considerably reduces residue levels in processed lettuce compared to fresh lettuce. It is confirmed that cutting, followed by washing and drying, considerably reduces the residues. A matrix effect in the dialyzation of the pesticides is observed and the in vitro study of bioavailability establishes a low percentage of stomach absorption capacity (<15%). The EDI/ADI ratios found in all cases were well below their ADI values, and the dietary exposure assessed (EDI) in fresh-cut lettuce showed no concerns for consumer health.     

Information processing in models for density-dependent emigration: A comparison

Density-dependent emigration has been recognized as a fitness enhancing strategy. Yet, especially in the modelling literature there is no consensus about how density-dependent emigration should quantitatively be incorporated into metapopulation models. In this paper we compare the performance of five different dispersal strategies (defined by the functional link between density and emigration probability). Four of these strategies are based on published functional relationships between local population density and emigration probability, one assumes density-independent dispersal. We use individual-based simulations of time-discrete metapopulation dynamics and conduct evolution experiments for a broad range of values for dispersal mortality and environmental stochasticity. For each set of these conditions we analyze the evolution of emigration rates in ‘monoculture experiments’ (with only one type of dispersal strategy used by all individuals in the metapopulation) as well as in selection experiments that allow a pair-wise comparison of the performance of each functional type. We find that a single-parameter ‘asymptotic threshold’ strategy - derived from the marginal value theorem - with a decelerating increase of emigration rate with increasing population density, out-competes any other strategy, i.e. density-independent emigration, a ‘linear threshold’ strategy and a flexible three-parameter strategy. Only when environmental conditions select for extremely high emigration probabilities (close to one), strategies may perform approximately equally. A simple threshold strategy derived for the case of continuous population growth performs even worse than the density-independent strategy. As the functional type of the dispersal function implemented in metapopulation models may severely affect predictions concerning the survival of populations, range expansion, or community changes we clearly recommend to carefully select adequate functions to model density-dependent dispersal.     

Automated detection of frog calls and choruses by pulse repetition rate

Anurans (frogs and toads) are among the most globally threatened taxonomic groups. Successful conservation of anurans will rely on improved data on the status and changes in local populations, particularly for rare and threatened species. Automated sensors, such as acoustic recorders, have the potential to provide such data by massively increasing the spatial and temporal scale of population sampling efforts. Analyzing such data sets will require robust and efficient tools that can automatically identify the presence of a species in audio recordings. Like bats and birds, many anuran species produce distinct vocalizations that can be captured by autonomous acoustic recorders and represent excellent candidates for automated recognition. However, in contrast to birds and bats, effective automated acoustic recognition tools for anurans are not yet widely available. An effective automated call-recognition method for anurans must be robust to the challenges of real-world field data and should not require extensive labeled data sets. We devised a vocalization identification tool that classifies anuran vocalizations in audio recordings based on their periodic structure: the repeat interval-based bioacoustic identification tool (RIBBIT). We applied RIBBIT to field recordings to study the boreal chorus frog (Pseudacris maculata) of temperate North American grasslands and the critically endangered variable harlequin frog (Atelopus varius) of tropical Central American rainforests. The tool accurately identified boreal chorus frogs, even when they vocalized in heavily overlapping choruses and identified variable harlequin frog vocalizations at a field site where it had been very rarely encountered in visual surveys. Using a few simple parameters, RIBBIT can detect any vocalization with a periodic structure, including those of many anurans, insects, birds, and mammals. We provide open-source implementations of RIBBIT in Python and R to support its use for other taxa and communities.     

多因素耦合的加工车间关键风险因素定量分析

为了准确分析加工车间关键风险因素,考虑多风险因子交互影响的情境,提出了一种基于模糊决策实验室分析法的加工车间关键风险因素定量分析方法。首先,从人员、设备、环境、物料和管理因素等5个维度辨识加工车间风险因素并建立风险因素集;基于此,采用三角模糊数对专家判断语义进行表征,然后运用DEMATEL法计算多因素耦合下的风险重要度,从而确定加工车间的关键风险因素。最后,以安徽省某机械加工车间为例,说明所提出方法的应用过程。结果表明,加强对安全制度和安全文化建设等关键风险因素的控制,有助于加工车间的风险控制,改善车间生产安全。