非畅流流域跨界水污染纠纷管理模型研究

结合我国流域的非畅流特点,提出了流域各地区作为独立决策单元、污染物人为调控和地区间污染物间接不影响等几个基本假设,构建了我国流域跨界水污染描述模型.分析了我国目前正在执行的污染物削减指令配额模型的优缺点,提出用行政、税收、排污权交易等手段解决我国日益严重的流域跨界水污染纠纷问题,为此建立了合作协调模型、税收宏观调控模型、排污权交易宏观调控模型.通过对淮河流域跨界水污染纠纷的具体应用分析了各种管理模型的资源利用效率.最后,通过各种管理模型的对比分析,指出选择合适的管理模型应与流域的实际情况相匹配.     

Agent‐Based Modeling to Simulate Contamination Events and Evaluate Threat Management Strategies in Water Distribution Systems

In the event of contamination of a water distribution system, decisions must be made to mitigate the impact of the contamination and to protect public health. Making threat management decisions while a contaminant spreads through the network is a dynamic and interactive process. Response actions taken by the utility managers and water consumption choices made by the consumers will affect the hydraulics, and thus the spread of the contaminant plume, in the network. A modeling framework that allows the simulation of a contamination event under the effects of actions taken by utility managers and consumers will be a useful tool for the analysis of alternative threat mitigation and management strategies. This article presents a multiagent modeling framework that combines agent‐based, mechanistic, and dynamic methods. Agents select actions based on a set of rules that represent an individual's autonomy, goal‐based desires, and reaction to the environment and the actions of other agents. Consumer behaviors including ingestion, mobility, reduction of water demands, and word‐of‐mouth communication are simulated. Management strategies are evaluated, including opening hydrants to flush the contaminant and broadcasts. As actions taken by consumer agents and utility operators affect demands and flows in the system, the mechanistic model is updated. Management strategies are evaluated based on the exposure of the population to the contaminant. The framework is designed to consider the typical issues involved in water distribution threat management and provides valuable analysis of threat containment strategies for water distribution system contamination events.     

Water Adherence Factors for Human Skin

On incidental dermal exposure to chemicals in water, a key exposure factor is the amount of water adhering to skin. Although soil adherence factors have been developed for risk assessment, measurements of water adherence on human skin have not been described. In the Environmental Protection Agency's (EPA's) dermal risk assessment guidance, dermal dose from environmental exposures is based upon the flux rate across the skin, which assumes that an unlimited amount of chemical is available for absorption. This assumption is applicable to certain exposure scenarios such as swimming and bathing. However, exposures to contaminated water frequently involve scenarios where the available chemical is limited by the amount of water adhering to the skin, for example, during accidental splashes. We conducted studies in human volunteers to investigate water adherence per unit area of skin after brief contact with water. In two sets of experiments, either water was applied with a micropipette to 10‐cm² areas of the lower leg, foot, and hand, or the foot and hand were briefly immersed in water. In males, using a micropipette, water adherence ranged from 1.93 (foot) to 7.13 μL/cm² (lower leg). In females, it ranged from 1.10 (lower leg) to 4.83 μL/cm² (hand). Hand and foot immersion resulted in relatively higher values of 6.89 and 5.17 μL/cm², respectively, in males, and 5.40 and 6.39 μL/cm² in females. Water adherence was affected by amount of body hair and type of exposure. Water adherence factors can be used to calculate the applied dose per unit area for exposures involving intermittent water contact.     

Do Reports on Drinking Water Quality Affect Customers' Concerns? Experiments in Report Content

The Safe Drinking Water Act Amendments of 1996 required U.S. utilities to report on drinking water quality to their customers annually, beginning in fall 1999, on the assumption that such reports would alert them to quality problems and perhaps mobilize pressure for improvement. A random sample of New Jersey customers read alternative versions of a water quality report, in an experiment on reactions to water quality information under U.S. Environmental Protection Agency (USEPA) rules. Experiment design was 2 x 3 + 1: two versions each--one with, one without, a violation of a health standard--of a report that was (1) Qualitative (without water quality numbers, thus not meeting USEPA rules); (2) Basic, with minimal information meeting the rules; or (3) Extended, adding reading aids and utility performance information; plus a control instrument without any hypothetical report. Results of ANOVA suggest the reports will have less effect than hoped or feared. These manipulations were successful: people reading the Qualitative versions were less likely to say that the report gave the amounts of substances found in the water, and those reading Violation versions were more likely to report a violation of a health standard. The main differences in responses to the report involved the judged adequacy of the information, and to a lesser extent responses on a Concern scale (constructed from measures of concern, judged risk, clean-up intentions, distrust of utility information, and doubt that the utility was doing all it could to improve water quality). Overall judgments of water quality and utility performance did not change, either relative to the controls or in before versus after responses. Qualitative reports performed worse than others, confirming the decision to have utilities report actual contaminant levels. Extended reports did only slightly better than the Basic versions on these measures. Many respondents had trouble identifying the presence or absence of substance amounts or violations, despite their seeming obviousness (e.g., in a "bottom line" summary on the front page of each report), suggesting many were not processing this information carefully. However, the pattern of responses for those who accurately identified the presence or absence of substance amounts or violations did not differ substantially from that for the group as a whole. Generic risk beliefs (serious local environmental problems; lack of control over risks to one's health) dominated demographic variables, attitudes toward utility water quality or trustworthiness, and the content and format of water quality reports in influencing concern about drinking water quality. Previous empirical and theoretical evidence for lack of change in public risk attitudes due to one-time or infrequent communications--e.g., role of personal experience, perseverance of prior trust or distrust--seems to be confirmed for annual water quality reports.     

基于单片机AT89C51的全自动变频恒压供水系统

介绍了一种新型的变频恒压供水系统.该系统根据供水管网的用水情况,调整水泵投入台数及转速,实行全自动恒压供水,达到高效节能的目的;其水泵用变频器软启动,对电网无冲击,能延长水泵的使用寿命.     

晚唐五代时期金河黑河水系变迁与环境演变

汉代黑河(删丹河,或名张掖河,又名弱水)与北大河(金河,又名呼蚕水)交汇入注居延海,汉代以后直到唐代之前都没有记载.<元和郡县图志>记载两水分流,金河流注白亭海,张掖河流注居延海.敦煌文献记载晚唐时金河与张掖河交汇流注居延海,使居延海湖面出现一个恢复期.此外,金河和黑河流域地区居民结构变化、农业人口和用水量减少、黑河径流量增加也是居延海湖面增加的原因.     

城市供水管网系统工况分析的研究

通过分析实际供水管网系统的特征，对管网工况分析所涉及的几个尚未解决的计算问题进行了研究，提出了用计算机进行工况分析的思路与框架，为管网运行调度及研究管网水质模型打下了良好基础．     

水资源开发利用的环境效应与反思

水资源开发利用带来了土壤盐碱化、水质退化、江河断流及生态环境破坏等环境效应 ,同时也留给人们一些重要启示。从马克思主义哲学的角度 ,揭示了人与自然、水资源、环境之间的相互依赖、相互作用、相互影响的内在关系。在水资源规划管理中 ,只有尊重自然规律 ,充分考虑水资源开发的负效应 ,才能真正实现水资源的可持续开发利用     

气浮综合改进设施处理高浓度造纸废水

本文报道了气浮综合改进设施处理高浓度造纸废水的流程和改革，结果表明：改进后的气浮设施COD去除率由60％提高到75％，SS去除率由51％提高到71％，气浮出水河直接回用于造纸的主要过程，处理效果明显优于单纯的气浮处理。而且改进部分投资少，动力消耗少，是处理高浓度造纸废水的简便易行、值得推广的方法。     

读《太子成道经》三题

敦煌变文<太子成道经>叙述释迦牟尼从其母"右胁出身胎"、"袖中生"出,这与印度古代的种姓等级制度密切相关,是婆罗门教所谓不同种姓的人从梵天不同部位生出的神话之体现,"右胁"出生主要是秦汉以后"尊右卑左"观念的影响;释迦太子出生后"九龙吐水"洗浴其身,"九龙"是佛教输入后中国化的产物;释迦牟尼娶妻时所问"三从",是借用儒家提倡的妇道,来表明印度古代妇女在宗法家族中的卑微地位.