基于矩张量的钢筋混凝土构件损伤声发射检测方法

为了利用声发射技术对钢筋混凝土构件损伤进行定量检测,将矩张量在地震工程学中反演震源机制的理论用于结构的声发射无损检测。阐述了基于矩张量理论的声发射检测技术原理,推导了利用矩张量理论反演裂缝机制(裂缝位置、类型和走向)的定量表达式。通过钢筋混凝土梁的四点弯曲试验,按照基于矩张量的声发射分析方法,明确裂缝机制,并与试验结果比较,探讨矩张量理论用于钢筋混凝土结构无损检测的有效性。结果表明:对于钢筋混凝土受弯构件,基于矩张量的声发射无损检测技术能定量地描述结构的裂缝机制,具有较好的准确性。     

Endocrine stress response in Oreochromis sp. from exposure to waterborne cadmium: the plasma cortisol analysis

Cadmium (Cd) is known as one of the most dangerous environmental and industrial pollutants. It has no biological function and accumulates mainly in metabolically active tissue even at low concentrations, which in turn may cause tissue damage. The effect of Cd on the endocrine systems of fish is not well known. To test the hypothesis that Cd is a chemical stressor, Oreochromis sp. were exposed to waterborne cadmium chloride and their endocrine stress response (plasma cortisol) was investigated after 4 days and 20 days. The plasma cortisol levels were analyzed using reverse-phase high performance liquid chromatography with UV detection (λ = 250 nm) after liquid–liquid extraction. The detection limit of the method was found to be 0.87 ng/mL plasma. This study provides evidence that Cd probably causes exhaustion of endocrine systems. Oreochromis sp. exposure to Cd resulted in a 15%–53% and 52%–91% suppression of cortisol release after 4 days and 20 days of exposure, respectively, in comparison with the control group. The results suggest that Cd still activates the endocrine system at 20 days and the interrenal cells of Oreochromis sp. were not impaired after 20 days of exposure to Cd.     

Human ecological effects of tropical storms in the coastal area of Ky Anh (Ha Tinh,Vietnam)

Vietnam is prone to tropical storms. Climate change effects contribute to sea level rise, floods, progression of the low water line and coastal erosion. This paper inventories the perception of local people, assesses and values main aspects of the livelihood damage caused by the tropical storms of the period 2008–2013 in three coastal communes of the Ky Anh District of the Ha Tinh Province in Central Vietnam. The communes were selected because the location of their coastal line is perpendicular to the storm itself, which made them prone to damage. The effects of increasingly extreme weather conditions on three communities in an area most affected by storms and floods on the local residents and their responses to these changing environmental conditions are analyzed and assessed. The results of questionnaires completed by randomly selected local inhabitants of these communes show that storms and related hazards such as flood, sea level rise and heavy rain are perceived as the most impacting climate change intensified phenomena on agriculture and aquaculture, livestock, household property and income. Opinions and measured data provided by the commune and district authorities allow estimating the total direct cost of the tropical storm at 1.56 million $US (The used conversion rate VND/$US is 21,730 when the research was conducted in 2014) during the period 2008–2013. The long-term costs of adaptation and social impact measures will be significantly higher. Details of the monetary figures allow identifying the physical and natural capital of the area as being most affected by the storm. Trend and cost analysis show that the total financial support for hazard prevention and management during 2014–2019 is estimated at 1.19 up to 1.32 million $US. Local stakeholders indicate that climate change adaptation should not be limited to technical measures such as strengthening dikes, but also should target planting protection forests and mangroves and land use planning. Financial support for the relocation policy, stakeholder involvement and integrating climate change adaptation in both the socioeconomic development master plan and local land use planning are also of importance.     

Motives,opportunities, and risks for private sector investment in protected areas with international importance: evidence from German companies

What motives do companies have to make a voluntary contribution to the protection and conservation of ecosystems? Could an international market for protected area certificates (PACs)—issued for geographical areas managed in accordance with social and environmental best practices—boost private investment? What are the market opportunities and risks that influence private sector investment? These questions are evaluated based on semi-structured expert interviews conducted in 39 German companies. Triangulation is used for data analysis to combine the advantages of qualitative and quantitative methods. Qualitative interview results complemented with the exploratory factor analysis allow identifying five motives for private sector investment, of which three are key motives in the early stage of developing PACs: direct financial benefits; the social legitimacy of entrepreneurial business; and the corporate dependency on ecosystems. Opportunities for private companies arise from the high marketing potential of certificates, the international orientation of the PAC market, and the bundling of different ecosystem benefits. Identified risks include a lack of differentiation, additional costs, and green washing. Depending on the transparency of the certification scheme, companies are aware that PACs could both improve and damage their credibility and reputation.     

土地供给、房价与中国人口半城镇化

近十多年来,中国房价快速上涨,人口半城镇化率也随之迅速上升。针对这一现象,本文首次将土地供给、房价与人口半城镇化置于同一框架下进行系统分析,采用两阶段最小二乘法,以土地出让面积作为房价的工具变量,有效克服模型的内生性,从理论和实证两个方面研究了房价上涨对人口半城镇化的影响。结果发现:土地供给减少导致房价上涨,进而推升了人口半城镇化率,抑制了农村转移人口市民化。房价每上涨一个百分点,人口半城镇化率大约上升0.189 4个百分点。在未考虑内生性的情况下,房价对人口半城镇化的影响严重被低估。而2003年后土地供给政策收紧且向中西部地区偏移是导致东部房价上涨进而推升人口半城镇化率的重要根源。另外,还发现对外开放程度提高以及人力资本积累均有利于降低人口半城镇化率,相反,财政负担能力和户籍制度改革则产生了不利影响。因此,为了降低人口半城镇化率,有序促进农村转移人口市民化,提出如下三点政策建议:(1)调整土地供给政策,并且健全住房供应体系,防止房价上涨过快。为此,需要增加东部地区以及大城市的土地供给,使土地供给与人口流动方向以及经济发展需求相匹配,同时增加廉租房和保障房的供应。(2)大力发展工业、服务业,并提高对外开放程度,以创造更多就业机会,增加居民收入,进而促进地区人口城镇化。(3)深化户籍制度,切实放宽农村转移人口的落户条件,同时还需要深化财政制度改革,增加地方公共服务并努力促进公共服务均等化。     

Impact of metal stress on the production of secondary metabolites in <Emphasis Type="Italic">Pteris vittata</Emphasis> L. and associated rhizosphere bacterial communities

Plants adapt to metal stress by modifying their metabolism including the production of secondary metabolites in plant tissues. Such changes may impact the diversity and functions of plant associated microbial communities. Our study aimed to evaluate the influence of metals on the secondary metabolism of plants and the indirect impact on rhizosphere bacterial communities. We then compared the secondary metabolites of the hyperaccumulator Pteris vittata L. collected from a contaminated mining site to a non-contaminated site in Vietnam and identified the discriminant metabolites. Our data showed a significant increase in chlorogenic acid derivatives and A-type procyanidin in plant roots at the contaminated site. We hypothesized that the intensive production of these compounds could be part of the antioxidant defense mechanism in response to metals. In parallel, the structure and diversity of bulk soil and rhizosphere communities was studied using high-throughput sequencing. The results showed strong differences in bacterial composition, characterized by the dominance of Proteobacteria and Nitrospira in the contaminated bulk soil, and the enrichment of some potential human pathogens, i.e., Acinetobacter, Mycobacterium, and Cupriavidus in P. vittata’s rhizosphere at the mining site. Overall, metal pollution modified the production of P. vittata secondary metabolites and altered the diversity and structure of bacterial communities. Further investigations are needed to understand whether the plant recruits specific bacteria to adapt to metal stress.     

程序化的未确知测度模型用于水环境质量评价

未确知测度模型用于水环境质量评价具有合理性。为使模型更加完善,提出将未确知测度模型建立过程标准化,使其具有通用性。并针对水质评价指标众多致评价过程复杂、计算量大的情况,利用MATLAB软件将标准化后的未确知测度模型设计为既定的程序,依靠计算机模拟来实现水质评价。通过对浮桥河水库水质的评价结果及与其他多种方法的对比,表现出标准化模型的客观性、合理性,MATLAB程序的实用性、快捷性。程序化的未确知测度模型标准化后可进行推广。     

程序化的未确知测度模型用于水环境质量评价简

未确知测度模型用于水环境质量评价具有合理性。为使模型更加完善,提出将未确知测度模型建立过程标准化,使其具有通用性。并针对水质评价指标众多致评价过程复杂、计算量大的情况,利用MATLAB软件将标准化后的未确知测度模型设计为既定的程序,依靠计算机模拟来实现水质评价。通过对浮桥河水库水质的评价结果及与其他多种方法的对比,表现出标准化模型的客观性、合理性,MATLAB程序的实用性、快捷性。程序化的未确知测度模型标准化后可进行推广。     

不同挂膜方式生物滴滤塔处理含H2S恶臭气体简

采用菌剂挂膜,活性污泥挂膜和自然挂膜3种不同方式形成生物滴滤塔,考察挂膜方式对生物滴滤塔去除H₂S恶臭气体的影响。结果表明,当进气H₂S浓度为5 mg/m³时,菌剂挂膜、活性污泥挂膜、自然挂膜形成的生物滴滤塔出气H₂S浓度分别为15.7~17.4、11.6~14.8和15.0~15.9 μg/m³;塔内压降分别为3~4 mm水柱、6 mm水柱和4~5 mm水柱;喷淋后滤出液中硫酸根的浓度分别为14、22和17 mg/L,硫的转化率分别为45%、60%和50%。当进气H₂S浓度增大至7 mg/m³时,3个塔经过7 d的调整后,均能达到稳定状态,稳定后3个塔中出气H₂S浓度和压降基本没变,喷淋后滤出液中硫酸根浓度依次增大至25、31和30 mg/L左右。采用活性污泥挂膜形成的生物滴滤塔处理H₂S的能力比菌剂挂膜和自然挂膜的高。     

Full-Scale Evaluation of the Thermal Stability-Based Hazardous Organic Waste Incinerability Ranking

De nombreuses études épidémiologiques ont observé dans des contextes différents une faible relation à court terme entre les particules et la mortalité cardio-pulmonaire, même quand les normes de qualité de l'air n'étaient pas dépassées. La causalité de cette relation est un enjeu de santé publique en raison de l'importance de la population exposée. Notre objectif est de faire l'inventaire critique des arguments utilisés dans 15 revues de la littérature publiées.

Nous expliquons l'importance de distinguer la validité de la causalité et analysons de façon systématique les différents critères de jugement dans le contexte des études écologiques temporelles. Notre conclusion est que la relation observée est valide et que la plupart des critères de causalité sont respectés. Diminuer le niveau d'exposition des populations aux particules est souhaitable. En Europe, en agissant à la source, notamment sur les émissions Diesel, on diminuera aussi d'autres polluants qui peuvent jouer un rôle sanitaire. Aux États-Unis, la situation est plus complexe car les particules sont surtout secondaires.

Il est également indispensable de poursuivre les recherches pour mieux connaître les déterminants des expositions globales des individus et mieux comprendre le rôle toxique des différents facteurs physico-chimiques des particules.