系统安全投入与事故率可能性边界模型研究

安全科学是一门新兴的交叉学科,根据安全科学的哲学原理和安全科学基本理论,结合经济学原理,分析安全投入与事故率的规律,在此基础上建立安全投人与事故率可能性边界模型,即“P-S”模型。详细分析和描述了“P—S”模型中各参数的安全意义,推导出“P—S”模型的基本表达式,并定量分析了表达式中参数的取值情况,得出系统存在合理安全投入区间、最佳安全投入和最佳安全经济效益事故率。通过分析发现模型可以客观反应系统的安全投入与事故率之间的对立统一规律,安全投入与事故率“P—S”模型的研究对科学、有效的进行安全投入,提高系统的安全效益和经济效益,降低事故率具有一定的意义。     

Predictive control based double-electrode submerged arc welding for filet joints

Double-electrode submerged arc welding (DE-SAW) is an innovative process to achieve the same metal deposition rate at reduced heat input. To maximally take advantage of this new capability, the heat input needed to produce acceptable welds needs to be reduced. A joint gap is successfully introduced to reduce the required heat input but it introduces variations affecting currents/heat input. To minimize the resultant variations in currents and resultant welds, the process is modeled and a multivariable predictive control algorithm is developed to control the currents at desired levels. Experiments verified the effectiveness of the resultant feedback controlled DE-SAW process.     

大气扩散模型AERMOD与CALPUFF输入数据的对比研究

科学地选取大气扩散模型是计算结果能够反映客现实际的前提.输入数据处理的正确与否直接影响后续大气扩散模型的预测结果.比较不同模型输入数据之间的差异是模型选取的主要依据之一.文章简述了大气扩散模型AERMOD和CALPUFF的技术流程,对两个模型的气象数据、地理数据和污染源数据进行了对比.对于利用大气扩散模型预测污染趋势具有一定的参考价值和实际意义.     

不同碳输入对天山雪岭云杉林土壤化学计量特征的影响

土壤C、N、P元素是构成森林生态系统的重要组分,通过研究外源碳输入改变对森林土壤化学计量特征的影响,有助于揭示森林生态系统的元素循环过程及平衡反馈机制.以天山雪岭云杉林作为研究对象,通过基于2 a的植物残体的添加和去除试验(DIRT),分析外源碳输入改变对土壤C、N、P化学计量特征短期影响,讨论不同处理下土壤化学计量特征与其他土壤理化因子的相互关系.结果表明：(1)土壤C、N、P含量在大部分土层均表现为双倍凋落物(DL)处理最高,按土层深度由浅到深依次为,土壤ω(C):168.92、119.88、103.33和64.23g·kg^-1;土壤ω(N):10.60、9.32、8.78和8.07g·kg^-1;土壤ω(P):0.50、0.45、0.37和0.36g·kg^-1;切根去凋落物(NI)处理最低,按土层深度由浅到深依次为土壤ω(C):104.56、89.24、48.08和43.96g·kg^-1;土壤ω(N):6.83、2.60、2.63和2.22g·kg^-1;土壤ω(P):0.4...     

基于硬件投入产出效益分析的上海市生活垃圾分类政策评价

本研究基于垃圾车、分类投放点、回收服务点、垃圾中转站4类硬件投入要素,以上海市垃圾分类政策实施效果作为研究对象,利用数据包络DEA分析方法,针对2020年1月~2021年6月上海市强制性垃圾分类具体的实施效果逐月展开分析和评测.结果表明,条例颁布后,上海市生活垃圾分类总体实施成效较为良好,综合效率、纯技术效率和规模效率平均值分别为0.957、0.993、0.963,均处于相对有效状态,但部分月份存在投入冗余及产出不足情况,仍有很大的进步空间.建议将投入要素均衡地作用到可回收物、干垃圾、湿垃圾以及有害垃圾的城市生活垃圾处理方面,进而提升上海市可回收物、干垃圾、湿垃圾以及有害垃圾的处理水平,提高政策实施效率.     

Improvement of Ecological Footprint Method and Application in Henan Province

1 INTRODUCTIONSustainability has now become a universal policy goal atleast in the official rhetoric. Indicators of sustainabledevelopment might give policy-makers and the factorsralpublic some feeling of whether a country is moving in amore or less sustainable direction. Leading approaches tomeasure sustainable development are reintroduced andreviewed, and different types of indicators to measuresustainable development are classified into three majortypes:(1) indicators based on system th…     

Parental perception of social risk and of positive potentiality of outdoor autonomy for children: The development of two instruments

An important factor that limits children's autonomy outdoors is parental perception of social danger and traffic danger. To obtain quantitative instruments for these dimensions, this work aimed to explore the validity and reliability of three scales. Two of them describe, respectively, problematic aspects of the area of residence linked to traffic and situations of social degradation that could constitute risk factors for the child's psychological and physical safety (Traffic Danger Perception Scale, Social Danger Perception Scale). The third scale investigates parental perception of the positive potentiality of outdoor autonomy for children's maturation and growth. Interviews were conducted with 377 mothers of children between 8 and 10 years of age residing in six different areas in Italy. The results indicated weak reliability of the Traffic Danger Perception Scale, which requires further investigation, and they confirmed the reliability and the construct validity of the Social Danger Perception Scale and the Perception of Positive Potentiality of Outdoor Autonomy for Children Scale. The perception of social danger was higher in mothers who live in larger urban contexts and who have more personal fear of crime and a lower sense of community. The positive perception of children's autonomy of movement was higher among mothers who live in greener areas, who have a greater sense of community and who have more neighbourhood relations.     

Distribution of anthropogenic cadmium and arsenic in arable land soils of Hainan,China

It is important to determine the distribution of anthropogenic heavy metals in arable land soils. Using Hainan Island as a study area, the background concentrations of cadmium (Cd) and arsenic (As) in arable land soils from different types of parent materials were estimated and then anthropogenic input distribution was determined by subtracting background concentrations from existing spatial distributions of Cd and As using ArcGIS spatial analysis tools. There were areas where the content of soil Cd and As did not show a change due to anthropogenic inputs, 8.4% As and 24.3% Cd content were below background concentrations, respectively. Soils with higher anthropogenic inputs were found around urban areas and the western part of Hainan Island. Data indicated that inputs were primarily produced by rapid urbanization and uncontrolled mining exploration. Anthropogenic Cd and As increases were also caused by excessive application of fertilizers.     

营养盐输入对太湖水体中磷形态转化及藻类生长的影响

外源营养盐输入会对湖泊水体中磷的形态转化及藻类生长产生影响.为研究其影响规律,于春季选取太湖梅梁湾水体为研究对象,以KNO3和K2HPO4添加系列氮磷负荷,在试验过程中对各形态磷的浓度、藻类生物量(Chl-a)和碱性磷酸酶活性(APA)进行同步分析测定.结果表明,春季太湖梅梁湾水体中浮游植物的生长主要受到磷限制,加氮对其生长没有明显的促进作用.加磷至SRP=0.015 mg·L-1的水体中浮游植物生长情况最好,叶绿素a的含量和生长速率(μ)最大.添加硝酸盐能显著促进APA的增长,提高水生生物对磷的吸收利用能力,加快磷循环的速率;磷酸盐对APA则具有活性诱导-抑制机制,当水体中磷酸盐浓度在一定范围内(PO3-4-P≤0.025 mg·L-1)时,酶活性有显著提高.对水体中磷的循环转化过程和碱性磷酸酶的活性诱导-抑制机制的研究结果有助于揭示藻类生长过程中营养盐的补偿途径,为深入揭示藻类暴发机制提供理论基础.     

基于MFA的1995-2005年中国物质投入与环境影响研究

运用物质流分析(Material Flww Analysis,MFA)方法,并在欧盟MFA指标体系的基础上增加了资源循环利用新指标,收集并分析了1995-2005年中国经济系统的物质投入和环境影响的2000多个数据,得到1995-2005年中国直接物质投入量与物质投入结构、国内物质输出量与污染排放结构、物质流强度的变化.结粜表明:十年来中国直接物质投入量与国内物质输出量增长均随GDP增长呈线性增长趋势;由于直接物质投入量的资源投入结构发生的巨大变化,导致工业固体废弃物的排放量不断增长;资源生产率出现低位下降;2005年中国资源循环利用率首次突破5%,但总体水平仍然低下.最后在计算结果基础上,指出MFA方法存在的不足之处.