Assessing vulnerabilities to the effects of global change: an eight step approach

In the recent years, global environmental change research has seen increased attention to the concept of vulnerability. There have been a growing number of vulnerability assessments, but relatively little discussion on appropriate and common methods. Here we propose a method to guide vulnerability assessments of coupled human–environment systems toward a common objective: informing the decision-making of specific stakeholders about options for adapting to the effects of global change. We suggest five criteria vulnerability assessments must at least possess to achieve this objective. They should have a knowledge base from various disciplines and stakeholder participation, be place based, consider multiple interacting stresses, examine differential adaptive capacity, and be prospective as well as historical. On the basis of these criteria, we present a general methodological guideline of eight steps. To examine whether these eight steps, if attentively coordinated, do in fact achieve the criteria, and in turn satisfy the objective of the assessment, we discuss two case studies. We expect most readers to identify some of the steps as part of their well-established disciplinary practices. However, they should also identify one or more steps as uncommon to their research traditions. Thus taken together the eight steps constitute a novel methodological framework. We hypothesize that if researchers employ this framework, then the products of the research will (1) achieve the objective of preparing stakeholders for the effects of global change on a site-specific basis, and (2) further the “public good” of additional insights through cross-study comparisons of research projects designed according to common principles.     

环境水样中痕量Fe3+的测定方法研究

在酸性介质中(pH 5.0),Fe3+能与硫氰酸盐生成稳定的配离子[Fe(SCN)6]3-,该配阴离子能与碱性717型阴离子交换树脂定量交换缔合,形成阴离子交换树脂(R+)--金属离子(Mn+)--硫氰酸盐(SCN-)三元配合缔合体系,其最大吸收波长分别为490 μm,与二元水相最大吸收波长相同,通过制作薄层测定了水中Fe3+含量.本法具有较高的灵敏度ε630Fe3+=2.4×105 L·mol-1·cm-1,测定0.6 μgFe3+6次,RSD=2.7%,实测了水样中,Fe3+含量并与AAS法测定结果比较,Fe3+测定的线性范围0～10 μg/25mL,体系检出限为0.12 μmol/L.     

城市地下工程与地下水污染

“2 1世纪是地下工程的世纪”,而城市地下工程与城市地下水系统又是一对相互作用的矛盾体 ,本文介绍了由于城市地下工程的兴建和使用造成地下水污染的几种主要作用方式 ,并针对这几种情况提出了相应的解决方案和对策。     

凹凸棒土复合净水剂处理印染废水

用活化后的凹凸棒粘土配制成复合净水剂处理印染废水，色度去除率达９３％以上，ＣＯＤ去除率达７４％，每立方米废水处理费用约０．１５元，压滤渣可用于制砖。     

Predicting particle deposition on HVAC heat exchangers

Particles in indoor environments may deposit on the surfaces of heat exchangers that are used in heating, ventilation and air conditioning (HVAC) systems. Such deposits can lead to performance degradation and indoor air quality problems. We present a model of fin-and-tube heat-exchanger fouling that deterministically simulates particle impaction, gravitational settling, and Brownian diffusion and uses a Monte Carlo simulation to account for impaction due to air turbulence. The model predicts that <2% of submicron particles will deposit on heat exchangers with air flows and fin spacings that are typical of HVAC systems. For supermicron particles, deposition increases with particle size. The dominant deposition mechanism for 1–10 μm particles is impaction on fin edges. Gravitational settling, impaction, and air turbulence contribute to deposition for particles larger than 10 μm. Gravitational settling is the dominant deposition mechanism for lower air velocities, and impaction on refrigerant tubes is dominant for higher velocities. We measured deposition fractions for 1–16 μm particles at three characteristic air velocities. On average, the measured results show more deposition than the model predicts for an air speed of 1.5 m s⁻¹. The amount that the model underpredicts the measured data increases at higher velocities and especially for larger particles, although the model shows good qualitative agreement with the measured deposition fractions. Discontinuities in the heat-exchanger fins are hypothesized to be responsible for the increase in measured deposition. The model and experiments reported here are for isothermal conditions and do not address the potentially important effects of heat transfer and water phase change on deposition.     

土壤毛管渗滤系统在浙江湖州某区新农村示范工程中的应用

针对浙江湖州某区生活污水的特点，分析了国内外生活污水处理的各种常规工艺，以采用先进的土壤毛管渗滤处理技术为主，结合能耗很低的微动力生化预处理和人工生态塘处理技术，取得了良好的处理效果。并详细介绍了土壤毛管渗滤处理系统的组成、各个处理单元的设计参数，分析总结了设计工艺的特点。     

Performance of various sub-grid scale models in large-eddy simulations of turbulent flow over complex terrain

Turbulent flow over a two-dimensional steep hill was analyzed by large-eddy simulations (LES). Here, six LES computations were carried out using four different sub-grid scale (SGS) models and two different ground surface conditions. The accuracy of these computations was assessed by comparing the results with those from an experiment by Ishihara et al. (An experimental study of turbulent boundary layer over a steep hill, Proceedings of the 15th National Symposium on Wind Engineering, 1998, pp. 61–66; J. Wind Eng. 89 (2001) 573). The results of the dynamic SGS models were in very poor agreement with those of the experiment. The poor prediction accuracy was mainly caused by the inaccurate estimation of the model coefficient near the ground surface. In order to improve the prediction accuracy of the dynamic SGS models, a hybrid SGS model, i.e., a combination of the standard Smagorinsky model and the dynamic Smagorinsky model, was introduced. The hybrid model provided very accurate predictions and produced the best results of the four SGS models compared here.     

Cr6+和Cr3+对水花生几种生理生化指标的影响比较

通过Cr6 和Cr3 对水花生 (Alternantheraphiloxeroides)的叶及根的某些生理生化指标影响的对比研究发现 ,Cr6 和Cr3 均能对水花生产生毒害 ;铬污染后 ,水花生的叶绿素含量、超氧化物歧化酶 (SOD)、过氧化物酶 (POD)、过氧化氢酶 (CAT)活性和可溶性蛋白含量 5项重要生理生化指标发生相应变化 ;Cr6 的毒性明显大于Cr3 ,根的受害程度比叶严重。     

Change in plant spatial patterns and diversity along the successional gradient of Mediterranean grazing ecosystems

In this study, we analyze the complexity of plant spatial patterns and diversity along a successional gradient resulting from grazing disturbance in four characteristic ecosystems of the Mediterranean region. Grazing disturbance include not only defoliation by animals, but also associated disturbances as animal trampling, soil compaction, and mineralization by deposition of urine and feces. The results show that woodland and dense matorral are more resistant to species loss than middle dense and scattered matorral, or grassland. Information fractal dimension declined as we moved from a dense to a discontinuous matorral, increasing as we moved to a more scattered matorral and a grassland. In all studied cases, the characteristic species of the natural vegetation declined in frequency and organization with grazing disturbance. Heliophyllous species and others with postrate or rosette twigs increased with grazing pressure, particularly in dense matorral. In the more degraded ecosystem, only species with well-adapted traits, e.g., buried buds or unpalatable qualities showed a clear increase with grazing. Indeed, the homogeneity of species distribution within the plant community declined monotonically with grazing impact. Conversely, the spatial organization of the characteristic plants of each community increased in the better-preserved areas, being also related to the sensitivity of the species to grazing impact. The degree of autocorrelation of plant spatial distribution at the species level and the information fractal dimension at the community level allow us to quantify the degree of degradation of natural communities and to determine the sensitivity of key species to disturbance.