Assessment of Ecological Risks at Former Landfill Site Using TRIAD Procedure and Multicriteria Analysis

Old industrial landfills are important sources of environmental contamination in Europe, including Finland. In this study, we demonstrated the combination of TRIAD procedure, multicriteria decision analysis (MCDA), and statistical Monte Carlo analysis for assessing the risks to terrestrial biota in a former landfill site contaminated by petroleum hydrocarbons (PHCs) and metals. First, we generated hazard quotients by dividing the concentrations of metals and PHCs in soil by the corresponding risk‐based ecological benchmarks. Then we conducted ecotoxicity tests using five plant species, earthworms, and potworms, and determined the abundance and diversity of soil invertebrates from additional samples. We aggregated the results in accordance to the methods used in the TRIAD procedure, conducted rating of the assessment methods based on their performance in terms of specific criteria, and weighted the criteria using two alternative weighting techniques to produce performance scores for each method. We faced problems in using the TRIAD procedure, for example, the results from the animal counts had to be excluded from the calculation of integrated risk estimates (IREs) because our reference soil sample showed the lowest biodiversity and abundance of soil animals. In addition, hormesis hampered the use of the results from the ecotoxicity tests. The final probabilistic IREs imply significant risks at all sampling locations. Although linking MCDA with TRIAD provided a useful means to study and consider the performance of the alternative methods in predicting ecological risks, some uncertainties involved still remained outside the quantitative analysis.     

基于ANSYS的板料成型系统模内加热模块热分析

针对目前板料热成形过程中存在的能量浪费、板料氧化严重等缺点,文章对模内加热方案进行研究探讨,使用ANSYS-Icepack对板料冲压成形的模内加热温度场进行模拟分析,并以此基础做出实物并调试对比模拟状况。结果显示：对于该模架,上下模1 000 W的热源同时加热时,加热组块最高温度可达近400℃,中间板材可加热到300 qC以上,10min之后散热和加热接近平衡。按该模型设计的实际加热系统的温度分布与模拟基本接近。该研究对模内加热模块的设计进行了模拟与初步的试验,将有助于板料热成形技术方面发展。     

关于新疆公元前第一千纪金属技术的几点思考

本文对新疆公元前第一千纪的金属技术进行了探讨,内容包括三个方面:铜器的合金组成、典型铜器的文化内涵以及其他金属器的出现与使用。该研究为全面揭示新疆的早期物质文化特征提供了一个新的视角,也有助于更好地认识新疆在早期东西文化交流史上的地位和影响。     

金属熔化热与熔点的关系

本文改进了计算金属熔化热的经验公式,所得结果较前人方法更接近实验值,且反映了各种金属的熔化熵并非恒定不变而与其熔点有关的事实。     

宋代通货膨胀问题辨析--兼论宋代纸币的性质

宋代是人类历史上首次大规模发行纸币的时代 ,由纸币、金属货币和有价证券共同构成的宋代货币体系 ,其相互关系的复杂及其不确定性导致了宋代通货膨胀的复杂和持久 ,也造成了对这一问题看法上的诸种分歧和不足。事实上 ,宋代正当中国古代社会经济大转型时期 ,其通胀成因错综复杂 ,表现出混合型的特征。宋代纸币是一种混合货币     

自信的概念、心理机制与功能研究

心理学领域中有关自信的系统研究并不多见。该文尝试用系统分析的观点提出了自信概念 :自信是一个多维度的心理系统 ,是个体对自己的正面肯定和积极确认程度。自信是通过对认知过程、动机过程及身心反应过程等若干中介过程的调节实现其主体作用机制的。自信对个体行为和心理健康具有重要影响。当前 ,自信研究在人才选拔与培养、健康人格塑造及具体教育实践等方面有着广阔的应用前景     

钻井实体膨胀管纵向金属流动的试验研究

为了研究井眼中钻井实体膨胀时的力学环境,选用35CrMo钢管,将金属塑性加工领域的网格法引入石油管程领域,对实体膨胀管的纵向金属流动规律进行了试验研究,发现膨胀管膨胀过程中存在明显的纵向金属流动不现象,并对造成这一现象的原因进行了分析。同时对膨胀后的管子材料进行了金相分析,金相分析结果证实了网法的分析结果,说明了将网格法引入石油工程领域是可行的。     

Effect of Particle Size on Risk Assessment of Direct Soil Ingestion and Metals Adhered to Children's Hands at Playgrounds

The quantity of heavy metals in soil is measured after 2‐mm sieving in Japan for risk assessment of direct soil ingestion. A study was conducted on the relationship between the size of soil particles and quantity of heavy metals in soil, and the particle‐size distribution of soil adhered to children's hands, and the risks of direct intake of soil considering the particle sizes ingested were evaluated. The results showed that smaller particles had a tendency to contain more heavy metals than bigger ones, that the particle size of approximately 90% of the soil particles from playgrounds adhered to children's hands was less than 100 μm, and that 2‐mm sieving in preparation for measuring heavy metal content caused underestimation of the risk of direct soil intake. The amount of heavy metals on children's hands after playing outside was investigated. Various metals and soil were adhered to their hands, and the amount of soil adhered could be estimated from the concentration of metals. To develop accurate risk assessment, the particle‐size distribution of ingested soil and more detailed scenarios of soil intake are necessary.     

被动腕关节曲面跟踪的模糊柔顺控制

介绍了一种利用被动腕关节的曲面柔顺研抛工具系统的结构原理,阐述了利用弹性适应体与直线步进电机的系统力控制方案,通过将力/位混合空间解耦,在独立的力空间对法向力进行主动控制。建立了力控制系统模型。采用模糊PID控制算法对控制参数进行实时整定,利用Simulink对控制系统性能进行了仿真实验。使用LabVIEW编制了控制系统软件,并结合一种自由曲面形状工件进行了法向力控制实验。仿真和实验结果均表明系统动态特性良好,对法向力的控制效果较好。     

遗传算法优化的神经网络熔深预测模型

依据熔化极气体保护焊(GMAW)焊接时对焊缝熔深的影响因素,结合遗传算法,建立以焊接电流、焊接电压、焊接速度和焊缝熔宽为输入、以熔深为输出的BP神经网络焊缝熔深预测模型。仿真试验和结果分析表明：使用遗传算法能得到神经网络较好的初始权值和阈值,能显著提高网络性能;所建模型符合已有的焊接熔深理论研究,并且预测误差较小,具有较好的泛比能力和较高的预测准确性,对工程实际具有一定的指导意义。