城市生活垃圾问题研究的系统动力学方法

利用被称为战略与策略实验室的系统动力学方法,建立了城市生活垃圾问题的系统动力学研究模型;以北京市为实例,探讨了垃圾排放及污染随人口和经济发展的变化,以及污染和占地损失、绿色GDP核算、居民家庭、企事业单位生活垃圾与建筑垃圾组合收费方案等问题.     

受内压椭圆封闭薄壁截面杆的小变形动力学性质

讨论受内压椭圆封闭薄壁截面杆的小变形动力学性质。把内压产生的应力作为初应力,利用薄壁杆理论和初应力位形上附加变形的线性理论,研究相对初应力位形产生的附加变形控制方程,由此给出小变形动力学性质的定量分析方法和拉压、弯曲、扭转固有频率用内压表示的数值结果。     

PFC-APG-SA水成膜泡沫防治油液储运火灾实验研究

为有效防治油液在储运过程中易发生火灾问题,针对油液储运火灾特点,研发1种PFC-APG-SA水成膜泡沫材料。基于发泡性能、表面张力、pH值和抗烧性能,对复配的8种水成膜泡沫液开展性能测试实验,优选出最佳配方。结合分子动力学模拟,探究复配表面活性剂在模拟体系界面中分子排布作用的微观机理。研究结果表明：新型水成膜泡沫液发泡倍数为9.5,泡沫形态稳固,表面张力为17.521 mN/m,抗烧时间约为784 s,用量小且可以有效抑制油液燃烧;在分子动力学模拟中,复配的表面活性剂分子在油表面排列更为紧密,与油之间的相互作用能绝对值为8 210.238 kJ/mol,相互作用强且结构稳定。研究结果可为水成膜泡沫在油液储运火灾防治中的应用提供一定参考。     

On the Distribution of Reindeer in the Middle and Northern Urals

Russian Journal of Ecology -     

Ecological economics: themes, approaches, and differences with environmental economics

This article provides a short overview of the main themes of ecological economics (EE). It is argued that EE provides a platform that fosters multidisciplinary environmental research by bringing together the core contributing disciplines – economics and ecology. In addition, EE is regarded as a pluralistic approach to environmental research that can be set opposite to, and has indeed developed as a response to, traditional environmental and resource economics. A comparison of the two fields is presented to clarify the essential differences between them. In addition, specific themes are examined in more detail. These include: sustainable development; the growth debate; international trade; dynamic processes; and behaviour and policy. Electronic Publication     

Developing an Ecosystem Perspective from Experimental Monitoring Programs: I. Demographic Responses of a Rare Geothermal Grass to Soil Temperature

The geysers panic grass [Dichanthelium lanuginosum Spellenberg var. thermale (Bol.) Spellenberg or DILA] is exclusively associated with surface geothermal manifestations in Sonoma County, California, USA (38°46′N, 122°38′W). Steam extraction by power plants could alter the subsurface distribution of heat and water to the site, potentially impacting subpopulations of this rare plant. The purpose of this study was to use demographic monitoring to determine: (1) temporal and spatial patterns of soil temperature in relation to the distribution of established DILA individuals at Little Geysers, (2) in situ response of experimental populations of DILA to spatial variations in soil temperature, and (3) habitat requirements of DILA as an indicator of its tolerance to variations in surficial geothermal features. Thermocouple transects and a datalogger provided data for characterizing the spatial and temporal patterns of soil temperature in four microhabitats (fumarole, DILA stand, Andropogon stand, and cleared). Experimental populations were established by precisely sowing and monitoring DILA seeds in these microhabitats. The results indicated that spatial and temporal variations in soil temperature had significant effects on the processes of germination, growth, survivorship, and reproduction, thus producing a readily observed metapopulation patch dynamic in relation to geothermal activity. Seasonal depressions of soil temperature near the fumaroles by cold air and prolonged rainfall events also promoted the emergence and survival of DILA seedlings in a microhabitat that was previously too hot to occupy. Over longer periods of time, DILA metapopulation dynamism reflected climatic and geothermal variation. Drought years inhibited germination for lack of water, but more importantly for the lack of requisite soil temperature depressions in the fumarole microhabitat. Wet years promoted subpopulation expansion into transition areas that were once too hot and dry. There have also been shifts in the underground distribution of steam into areas distant from known geothermal features. The demographic responses of DILA to spatial and temporal variations in soil temperature indicate that heat is an absolutely essential component of the steam resource. In its absence, germination, seeding survivorship, growth, and maturation are significantly inhibited even if soil conditions are favorable and potential competitors are controlled. Ultimately, persistence of the species depends on maintaining the ecosystem dynamic of colonization and extirpation in response to variations in surficial geothermal features over long spatial and temporal scales. This should shift management perspective from its narrow focus on individual plants to a wider focus on monitoring the essential habitat component of steam.     

Long memory and chaotic models of prices on the London Metal Exchange

Many financial time series exhibit irregular behaviour. Economic theory suggests that this irregular behaviour might be due to the existence of nonlinear dependence in the markets. Thus, economic time series are governed by nonlinear dynamics.The purpose of this paper is to investigate price behaviour in the London Metal Exchange market. Thus, this study will test the two most attractive nonlinear models—long memory and chaos—on six metal commodities to ascertain which model is consistent with the observed metal price nonlinear dynamics.Application of long memory and chaos analysis provides new approaches for assessing the behaviour of metal prices. We identified, in tin, a case of chaos. Our empirical results in the case of aluminium support the long memory hypothesis. A short memory model explains the underlying processes of the nickel and lead returns series, while zinc returns reflect an anti-persistent process. To our knowledge, this is one of the first attempts to apply long memory and chaos analysis in the evaluation of the behaviour of metal prices.     

有机磷和无机磷对铜绿微囊藻生长的影响及动力学分析

以β-甘油磷酸钠和K₂HPO₄为例,研究了以有机磷或无机磷为磷源时,铜绿微囊藻的生长过程,并应用Monod模型对结果进行了动力学分析.根据计算,以K₂HPO₄为磷源时,铜绿微囊藻最大比增长率(μ_max)为1.107 d-1,对磷的半饱和常数(Ks)为0.004 8 mg/L;以β-甘油磷酸钠为磷源时,铜绿微囊藻μ_max为0.882 d-1,Ks为0.006 5 mg/L.在一定质量浓度范围内,铜绿微囊藻的最大现存量及最大比增长率均随磷质量浓度的增加而增大;在试验条件下铜绿微囊藻达到90%μ_max时,ρ(K₂HPO₄)为0.042 mg/L,ρ(β-甘油磷酸钠)为0.059 mg/L;此外,磷形态及其质量浓度对铜绿微囊藻的指数增长时间影响较大,从而对其最大现存量造成影响.      

曝气生物滤池处理含氟苯酚化工废水

采用曝气生物滤池工艺对含氟苯酚工业废水进行处理研究,主要考察了气水比、水力负荷、进水pH对处理效果的影响。氟苯酚和可吸附有机氟去除率随着气水比升高而增大,但气水比达到6∶1后又降低,最佳气水比为6∶1。随着水力负荷增大,有机物去除率减小,确定最佳水力负荷为0.58 m3/(m2.h)。进水pH在5.0~9.0范围内,BAF对氟苯酚的去除率都在90%以上,当pH达到9.5时去除率急剧降低到30%左右。当进水浓度为40 mg/L,气水比为6∶1,水力负荷为0.58m3/(m2.h),pH 6.5,出水效果稳定,出水氟苯酚、可吸附氟代有机物、氟离子含量均达到了《污水综合排放标准》(GB8978-96)一级标准。氟苯酚生物降解符合一级动力学。     

Production disruption management for R/M integrated supply chain using system dynamics methodology

The impacts of production disruption in Remanufacturing/Manufacturing (R/M) integrated supply chain on the sales and the methods of production disruption management were studied. A system dynamics model for the R/M integrated supply chain with production disruption was improved by system dynamics methodology. The numerical examples were shown to illustrate the simulation results. The impacts of different recovery times of production disruption on the sales were presented. In order to mitigate the disruption risks and ensure the sales at the needed sales ratio, the methods for setting multi-echelon inventory levels before the occurring of the production disruption and the methods for making back-up plans after the production disruption occurs were given.