城市生活垃圾、污泥和煤粉混合燃料热值的研究

为了寻求生活垃圾和污泥的高效资源化、能源化方法.选取生活垃圾、污泥和煤粉的混合,枯枝落叶,助燃剂MnO2,脱硫剂 CaO 为控制因子,安排正交试验,成型加工为混合燃料.测定其热值,并通过正交分析,筛选出燃料最大热值组合,即混合时垃圾、污泥、煤粉的比例为 1:1:2,枯枝落叶所占比例为 0%,助燃剂 MnO2 含量为 0.18%,脱硫剂 CaO 含量为 1.5/(100 g),该燃料的热值为 17.8898 kJ/g.为该混合燃料的推广与应用提供理论依据.     

Stability and Mixing of a Vertical Axisymmetric Buoyant Jet in Shallow Water

The stability, mixing and effect of downstream control on axisymmetric turbulent buoyant jets discharging vertically into shallow stagnant water is studied using 3D Reynolds-averaged Navier–Stokes equations (RANS) combined with a buoyancy-extended k –ε model. The steady axisymmetric turbulent flow, temperature (or tracer concentration) and turbulence fields are computed using the finite volume method on a high resolution grid. The numerical predictions demonstrate two generic flow patterns for different turbulent heated jet discharges and environmental parameters (i) a stable buoyant discharge with the mixed fluid leaving the vertical jet region in a surface warm water layer; and (ii) an unstable buoyant discharge with flow recirculation and re-entrainment of heated water. A stratified counterflow region always appears in the far-field for both stable and unstable buoyant discharges. Provided that the domain radius L exceeds about 6H, the near field interaction and hence discharge stability is governed chiefly by the jet momentum length scale to depth ratio l_M/H, regardless of downstream control. The near field jet stability criterion is determined to be l_M/H = 3.5. A radial internal hydraulic jump always exists beyond the surface impingement region, with a 3- to 6-fold increase in dilution across the jump compared with vertical buoyant jet mixing. The predicted stability category, velocity and temperature/concentration fields are well-supported by experiments of all previous investigators.     

The effects of different mixing intensities during anaerobic digestion of the organic fraction of municipal solid waste

Mixing inside an anaerobic digester is often continuous and is not actively controlled. The selected mixing regime can however affect both gas production and the energy efficiency of the biogas plant. This study aims to evaluate these effects and compare three different mixing regimes, 150 RPM and 25 RPM continuous mixing and minimally intermittent mixing for both digestion of fresh substrate and post-digestion of the organic fraction of municipal solid waste. The results show that a lower mixing intensity leads to a higher biogas production rate and higher total biogas production in both cases. 25 RPM continuous mixing and minimally intermittent mixing resulted in similar biogas production after process stabilization, while 150 RPM continuous mixing resulted in lower production throughout the experiment. The lower gas production at 150 RPM could not be explained by the inhibition of volatile fatty acids. Cumulative biogas production until day 31 was 295 ± 2.9, 317 ± 1.9 and 304 ± 2.8 N ml/g VS added during digestion of fresh feed and 113 ± 1.3, 134 ± 1.1 and 130 ± 2.3 N ml/g VS added during post digestion for the 150 RPM, 25 RPM and minimally mixed intensities respectively. As well as increasing gas production, optimal mixing can improve the energy efficiency of the anaerobic digestion process.     

Analysis for Chemical Characterization of Atmospheric Aerosols Application of X-ray Microprobe System and Double Thin Film Method

The X-ray microprobe system was applied to ultra trace characterization of single Kosa aerosols and non-Kosa aerosols simultaneously collected at Yasaka, Japan and TaeAnn, Korea. We demonstrated remarkable mass increase of heavy metals as well as soil components in individual particles during the Kosa event compared with the non-Kosa period at Yasaka. Backward trajectory analysis suggested that the Kosa samples were in the mixing state of mineral components and anthropogenic heavy elements. Double thin film method was applied to investigate the seasonal change of the mixing states of single sea-salt aerosols associated with chlorine loss due to the heterogeneous reactions between sea-salt particles and acidic gases. It was revealed that the percentages of both chloride-nitrate mixed particles and sulfate-nitrate ones were larger in wintertime than those in summertime and fraction of chloride-nitrate mixed particles increased with an increase of particle size. Comparison between the size-segregated bulk analysis and the single particle analysis demonstrated that remarkable chloride depletion occurred in coarse particles sampled on May in the former analysis, while chloride depletion in coarse particles was not marked in the latter analysis. The discrepancy attributes to the difference of the sampling time between both analyses because significant change of air mass route occurred during the bulk sampling after completion of the single particle sampling.     

天津市区不同土地利用类型地表径流污染特征及治理对策

剖析土地利用方式与污染物的内在联系是非点源污染研究基本出发点.本文研究了天津市区屋面、商业区、交通区、居民区不同土地利用类型径流污染特征,并针对不同的污染情况提出雨水利用与污染防治的合理化建议.     

溶氧条件对美人蕉和风车草根系泌氧特征的影响

采用标准氧化染色法研究了美人蕉和风车草在水培畜禽废水自然、缺氧和好氧3种溶氧状态下根系径向泌氧（Radial oxygen loss,ROL）类型的变化和特征,采用显微镜明暗场观察了相应的根系横截面特征。结果发现美人蕉在3种溶氧状态下根系径向泌氧类型分别为均匀强泌氧、根尖强烈泌氧和不泌氧3种;风车草的径向泌氧类型则分别...     

基于RBF的起重作业岗位人因可靠性预测

为提高起重作业可靠性,防止人因失误酿成事故,针对人因失误的随机性、模糊性和不确定性特点,提出运用具有非线性映射能力和容错能力的径向基函数(RBF)神经网络,分析人因失误非线性动力学过程。以起重机操作岗位作为人因可靠性分析(HRA)实例,首先,建立基于"作业人员、交流界面、作业环境、作业特性、作业组织"的人因可靠性预测指标体系,并对指标进行量化;其次,根据人因可靠性原理,统计出人因失误次数,给出人因失误率;最后,通过对"人的疲劳和情绪、交流通道、作业复杂程度和时间裕度、照明环境和风力影响、工作强度和安全监管"等因素的分析,构建基于RBF的起重机操作岗位人因可靠性预测分析神经网络模型。分析结果表明,RBF预测分析同时包含人的操作可靠性与认知可靠性,预测结果同现场实际观测结果的符合度达到92.0%。     

基于QPSO-RBF的瓦斯涌出量预测模型

为了提高径向基(RBF)网络预测瓦斯涌出量的泛化能力,提出QPSO-RBF模型。该模型采用量子粒子群(QPSO)算法优化RBF网络隐层基函数中心、扩展系数以及输出权等初始参数,将网络参数编码为QPSO学习算法中的粒子个体,在全局空间中搜索最优适应值参数。其中,RBF网络选取5-3-1的精简结构,采用5个变量作为影响因子预测瓦斯涌出量。结果表明,经QPSO优化后的RBF网络模型预测结果稳定且唯一,其泛化指标平均相对变动值(ARV)为0.012 2。与PSO-RBF、RBF模型预测结果比较,QPSO-RBF模型的泛化能力和网络训练速度优于前2种;预测精度约为PSO-RBF模型的1.5倍、RBF模型的4倍。     

陈行水库氨氮完全混合模型研究

建立了陈行水库氨氮完全混合模型,对氨氮浓度进行了模拟预测,并讨论了结论.     

海水混合和层化对叶绿素a垂直分布的影响

根据长江口海区、近岸浅水区、黄海冷水团海区和水深超过200m的陆架区等四个区域的定点调查获得的数据，分析了温度、盐度与叶绿素a垂直分布的相互关系。结果表明，长江口海区，陆源径流与海水混合不充分，表层营养盐含量较高，表层叶绿素a含量高于中下水层。近岸浅水区的苏北近岸海水垂向没有温跃层和盐跃层，叶绿素a的垂向分布也均匀，东海西部沿岸出现逆温跃层和逆盐跃层，海水垂直混合不充分，叶绿素a含量(6．72mg／m^3)在10m深水域最高。黄海冷水团海区海水的垂直混合不充分，叶绿素a的垂直变化显著，高值区出现在温跃层下方(4．37mg／m^3)。水深超过200m的陆架区，温度的阶梯状结构、营养盐跃层、光照等因素共同导致整个水层叶绿素a含量普遍较低。同时，结合历史资料分析认为，海水的混合、温度和盐度的层化将影响营养盐的浓度和分布，从而影响海水中叶绿素a的垂直分布。