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1.
Interstellar water in meteorites?   总被引:1,自引:0,他引:1  
D/H ratios of two meteorites (Renazzo CR and Semarkona LL3), which are known to exhibit the largest departures from the terrestrial hydrogen isotopic ratios, have been determined with the CRPG Nancy ion microprobe. Correlations between the D/H ratios and the chemical compositions (H2O, K, Si, C/H) of plausible hydrogen carriers were observed. From these correlations, it is possible to show that, contrary to previous interpretations, phyllosilicates are the carriers of the deuterium-rich hydrogen in Semarkona and Renazzo: 870 x 10(-6) > or = D/H > or = 670 x 10(-6) (+4600 > or = deltaD > or = 3300%) and > or = 320 x 10(-6) (deltaD > or = 1050%), respectively. Hydrogen is also present in the chondrules of these two deuterium-rich meteorites. The large differences in D/H ratios between matrix (up to 700 x 10(-6), deltaD up to +3500%) and chondrules (from 120 x 10(-6) (deltaD = -230%) to 230 x 10(-6) (deltaD = +475%)) show that hydrogen in chondrules cannot originate from the matrix by simple contamination or diffusion processes. The high D/H ratios measured in water-bearing minerals could not have been produced thermally within a dense solar nebula. Chemical reactions (i.e., involving ions or radicals), taking place in interstellar space or in the outer regions of the nebula at 110-140K are presently the only conceivable mechanisms capable of yielding such isotopic enrichments. Water in these meteorites should no longer be considered as a simple product of nebular condensation under equilibrium thermodynamic conditions at T > or = 160K.  相似文献   

2.
Weather modification operations are the intentional alteration of weather and cloud water conditions using technologies such as cloud seeding. Post-socialist authoritarian China is the world’s leading user of state power for rainfall enhancement through weather modification, with diverse purposes including agriculture production, water security, ecological preservation, and mega events. We argue that weather modification in China needs to be understood as a facet of ecological modernization, in which the authoritarian state believes that precipitation can be controlled through the use of advanced technologies, thus transforming clouds into a kind of cloud water resource. Two political dimensions are highlighted to understand precipitation control and utilization of cloud water: the first is a new ideological politics of the changing human-weather relationship from ‘adaptation to the weather’ to ‘taming the weather”; the second is volume politics that presents unique characteristics of airborne water as opposed to terrestrial and groundwater.  相似文献   

3.
Urban political ecology attempts to unravel and politicize the socio-ecological processes that produce uneven waterscapes. At the core of this analysis are the choreographies of power that influence how much water flows through urban infrastructure as well as where it flows, thereby shaping conditions and quality of access in cities. If these analyses have been prolific in demonstrating uneven distribution of infrastructures and water quantity, the political ecology of water quality remains largely overlooked. In this paper, we argue that there is a clear theoretical and practical need to address questions of quality in relation to water access in the South. We show that conceptual resources for considering differentiated drinking water quality are already present within urban political ecology. We then contend that an interdisciplinary approach, highlighting the interdependencies between politics, power, and physiochemical and microbiological contamination of drinking water, can further our understandings of both uneven distribution of water contamination and the conceptualisation of inequalities in the urban waterscape. We illustrate our argument through the case of water supply in Lilongwe, Malawi. Our political ecology analysis starts from an examination of the physicochemical and microbiological quality of water supplied by the formal water utility across urban spaces in Lilongwe. We then present the topography of water (quality) inequalities in Lilongwe and identify the political processes underlying the production of differentiated water quality within the centralised network. This paper thereby serves as a deepening of urban political ecology as well as a demonstration of how this approach might be taken forward in the analysis of urbanism and water supplies.  相似文献   

4.
Water used to be regarded as a classic renewable resource, on the reasonable grounds that (in most places, at least) it has a tendency to keep on falling from the sky. However, in recent decades concerns have begun to mount that water is being used consumptively (in some places, at least). This article examines the concept.  相似文献   

5.
Peter Newby 《GeoJournal》1997,43(4):351-358
Urban planners have to develop a planning doctrine (Faludi and Van der Valk 1990). This concept stands for a body of thoughts concerning (a) spatial arrangements within an area, (b) the development of that area; and (c) the way both should be handled. To be successful, they need a planning community (planners, top officials and sub-national establishments for political support) that nurtures it. The planners of the Amsterdam General Extension Plan (1935) developed a doctrine that covers three levels of functions and activities: (1) Amsterdam is a regional centre, a closed functional system, an orthogenetic city. (2) a monocentric urban form and (3) homogeneous neighbourhood communities around a common neighbourhood centre (church, school, medical services, shops). Since the early 1970s Amsterdam has become (1) an international centre, a heterogenetic city, part of a network city system, (2) has developed into a polycentric urban region, and (3) has been acquiring ethnically mixed quarters, divided communities losing their basic function as common neighbourhood centres and even as control areas or domains (Hägerstrand 1970). So in Amsterdam the planning-doctrine was not particularly successful.  相似文献   

6.
The BOCIM method (bottleneck-focused continuous improvement) has been designed to support the optimum adaptation of a local water resources management depending on regional conditions to ensure a sustainable supply of water. Being an interdisciplinary approach, the BOCIM method tries to take into account all the factors affecting the water supply. Geared to solving water problems, it is used to: identify and solve whatever the core problem happens to be in a regional water system by applying the bottleneck-concentrated strategy (Mewes in Orell Füssli Management, 112 p, 2000); replace the fragmented project-based approach with continuous improvement; run a management system-orientated quality management standard (e.g. ISO 9001).  相似文献   

7.
8.
In order to maintain the reservoir pressure and improve oil recovery efficiency, water flood recovery is used commonly in the middle and last periods of oilfield exploitation. At the same time, in order to avoid environmental pollution, the oilfield sewage should be reinjected. During that manufacture, variations in the conditions of pressure, temperature and unstability and incompatibility of thermodynamics make scale formation in water flood assize, casing, bottom of the wells, surface equipments and gathering lines. Taking the Daqing oil field for example, in which the surface gathering lines the scale forming is comparatively serious. In order to improve crude oil processing effect to warm up wet oil, this measure results in scale formation constant in pipelines and equipments, so inner diameter becomes less, leading to back pressure ascent in pipelines, the loss of efficiency of processing equipment, these all have a strong impact on normal activities in oilfield, increase the frequency of maintenance repairs and replacements for pipelines and equipments, and reduce the completion benefit. So forecasting the scaling tendency of surface gathering pipelines, and judging the degree of the scaling tendency or possibility, preventing and controlling scaling effectively is not a negligible research topic in petroleum production technology and oil-gas-water treatment technology. This paper introduces the fouling process, fouling mechanism and the influence factors of the scale, mainly analyses the formation mechanism of calcium carbonate and calcium sulfate, and some factors, such as temperature, pressure, salinity and some thermodynamics conditions. All these factors lead to changes in ionic equilibrium condition, so they will influence the fouling. This paper analyses the main kinds of scale in the gathered transportation water pipeline in the forth plant in the Daqing Oilfield, adopts the method of saturation exponent and energetic solubility to forecast the trend of fouling, reduces the calcium carbonate showing scaling tendency, calcium sulfate having the possibility of scaling.  相似文献   

9.
The last few decades have seen increasing attempts to foster ‘collaborative’ and ‘participatory’ approaches to spatial planning and decision-making, with a more sophisticated conceptualisation of the contested term, participation. Participatory, ‘bottom-up’ geo-information technologies have been concurrently developing and these are expected to strengthen participatory spatial planning; important among these has been the transformation of conventional mapping and GIS tools into Participatory GIS (PGIS). In this paper we explore the potential contributions of participatory geo-information tools towards participatory spatial planning, in terms of the principles and criteria of good governance. We discuss five fundamental principles of ‘good’ governance: accountability, legitimacy, respect, equity, and competence, and the potential of geo-information tools to contribute to, and detract from, such principles; although we focus especially on participation and the recognition and validation of local knowledge. We derive criteria for the five principles, and we identify a range of evaluation questions which can be operationalised so as to interrogate the criteria for judging the contribution of participatory tools and participatory spatial planning activities. We conclude by summarily assessing the potentials of participatory geo-information tools, particularly participatory mobile GIS, participatory 3-dimensional modelling, and visualisation features in PGIS.  相似文献   

10.
Kougkoulos  Ioannis  Merad  Myriam  Cook  Simon J.  Andredakis  Ioannis 《Natural Hazards》2021,109(2):1959-1980

France experiences catastrophic floods on a yearly basis, with significant societal impacts. In this study, we use multiple sources (insurance datasets, scientific articles, satellite data, and grey literature) to (1) analyze modern flood disasters in the PACA Region; (2) discuss the efficiency of French public policy instruments; (3) perform a SWOT analysis of French flood risk governance (FRG); and (4) suggest improvements to the FRG framework. Despite persistent government efforts, the impacts of flood events in the region have not lessened over time. Identical losses in the same locations are observed after repeated catastrophic events. Relative exposure to flooding has increased in France, apparently due to intense urbanization of flood-prone land. We suggest that the French FRG could benefit from the following improvements: (1) regular updates of risk prevention plans and tools; (2) the adoption of a build back better logic; (3) taking undeclared damages into account in flood risk models; (4) better communication between the actors at the different steps of each cycle (preparation, control, organization, etc.); (5) better communication between those responsible for risk prevention, emergency management, and disaster recovery; (6) an approach that extends the risk analysis outside the borders of the drainage basin; and (7) increased participation in FRG from local populations.

  相似文献   

11.
 Groundwater plays an important role for urban and industrial water supply in northern China. More than 1000 groundwater wellfields have been explored and installed. Groundwater provides about half the total quantity of the urban water supply. Complete regulations and methods for the exploration of groundwater have been established in the P.R. China. Substantial over-exploitation of groundwater has created environmental problems in some cities. Some safeguarding measures for groundwater-resource protection have been undertaken. Received, August 1997 · Revised, February 1998 · Accepted, April 1998  相似文献   

12.
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14.
Following complaints about water shortages in some areas of Gweru, the paper assessed the availability of enabling capacities to efficiently and sufficiently deliver water to the residents of Gweru in line with the existing level of demand. The key inspected capacity aspects were infrastructure, human resources, finances and physical availability of raw water at source. Purposively selected informants from Zimbabwe National Water Authority (ZINWA) and Gweru city council (GCC) provided data on the infrastructural, financial and human resources situation of GCC. Dam levels data for Gweru’s three supply dams were obtained from ZINWA records through the assistance of Sanyati Catchment Hydrologist. The raw water availability was assessed with the aid of Mann–Kendall test using a 10 years period data set from 2003 to 2012 for trend analysis. Findings revealed that the water sources were not experiencing major changes in water levels, to be precise, the changes were insignificant. However, given the increase in population and demand, any slightest negative change in the supply chain would further widen the gap between supply and demand. The study also uncovered that GCC had challenges in terms of the infrastructure, mainly due to financial constraints. Notably, GCC was not experiencing high staff turnover, but it was however, seriously under staffed and failing to effectively monitor water use in the city. Therefore, strong financial injection is required to support staff and resuscitate the reticulation system. Given the perpetual water shortages in Gweru and the status quo in the supply chain, water demand management strategies, wastewater use and consumer education are consequently proposed as measures that would ensure continuous water supply for all needs in the city.  相似文献   

15.
Amid a rapid expansion of global investments in biofuels there has been an equally rapid proliferation of concerns about the inadequacies of current governance schemes to mitigate the environmental impacts of growing agroenergy production. Managing the land use practices of small producers in a way that ensures their activities are financially and environmentally sustainable is a particularly pressing issue that has been overlooked in research on biofuel governance. I illuminate these challenges through an ethnographic study on the multiple breakdowns of environmental governance in the Southern Goiás region of Brazil, a major expansion region for sugarcane ethanol production. I focus on one of the most pressing compliance issues among small and medium size sugarcane farmers; their persistent use of federally mandated conservation areas for cattle production. I find that while these transgressions are often perceived by administrators and officials as being the result of a lack of “environmental awareness” among rural farmers, they are better understood as a safety net to protect landowners against perceived risks of sugarcane production. These violations are further enabled by continuing ambiguity in the enforcement structure for conservation legislation in the region. Recalibrating regulatory systems to better address these issues of accountability and risk is a critical step toward improving environmental governance of global biofuel commodity chains.  相似文献   

16.
In Vietnam, initial programs to Reduce Emissions from Deforestation and Forest Degradation (REDD+) have proliferated through international finance and new governance regimes for climate change mitigation. National capacity and legal frameworks have been adjusted to make the country eligible for REDD+ financing. In some local areas, activities have been implemented to ‘produce’ carbon credits intended for the international voluntary carbon market. Through a case study of a pilot REDD+ project in the Central Highlands of Vietnam, we examine how REDD+ has intersected with property rights institutions and agrarian change to influence changing property relations and commodity markets. Our findings show that REDD+ implemented through state and local institutions has articulated with the local political economy to coproduce conditions that embody local norms, needs, and desires. Specifically, local actors negotiate state-sanctioned tenurial instruments used for REDD+ governance, not for the purposes of carbon sequestration but instead in order to reassert their rights to land and forest for the cultivation of boom crops—the antithesis of REDD+ objectives. In the fine balancing act of adjusting local forestland holdings, REDD+ implementation has effectively facilitated increased opportunities for upland villagers to strategically claim land titles from local political authorities in the form of communal land certificates for forests called ‘Red Books’. In securing communal Red Books, villagers redefine or co-constitute the purpose of REDD+ to secure land for cash crop and commercial timber production. As with other forms of environmental governance, REDD+ is thus co-constituted locally in line with state and local institutions and histories and present day realities.  相似文献   

17.
《Applied Geochemistry》1998,13(3):329-337
The Oder river drains a highly polluted industrial area and enters the Baltic Sea through a system of shallow lagoons. Surficial sediments in the discharge area of the Oder are highly enriched in heavy metals compared to their preindustrial background levels. Pore-water studies in short sediment cores reveal anoxic environments over the entire sediment column, except for a suboxic layer in the uppermost 5 to 20 mm of the sediment where Mn- and Fe-oxyhydroxides are reduced by organic matter. Heavy metals (such as Cu, Zn and Pb) are mobilized within the suboxic zones in the inner lagoon (represented by the Oder Lagoon) and in the open Baltic (represented by the Arkona Basin). The Achterwasser, located between the Oder Lagoon and the Arkona Basin, is directly affected by sea-level fluctuations in the Baltic. Pore-water studies indicate that, in contrast to the situation in the Oder Lagoon and Arkona Basin, surficial sediments of the Achterwasser represent a sink for heavy metals. This is associated with the high rate of Fe-sulphide formation occurring there, at least seasonally during salt-water inflow.  相似文献   

18.
This article critically investigates recent water governance shifts, particularly constitutional changes implemented in several Latin American countries that highlight a ‘right to water’ as well as recent efforts that invoke such a right in conjunction with bans on private water provision (e.g. Uruguay, Ecuador, and Bolivia). Drawing on legal research, document review, and interviews, the article investigates the historical, political and discursive scaffolding of these constitutional changes in several case study contexts, including attention to implementation issues and ongoing challenges following the reforms. Placing these shifts within the broader context of neoliberalization of water governance of the past several decades, the analysis attends to both the specific historical–contextual formations that are important to understand the constitutional reforms, as well as the ways these changes might be usefully understood as connected to broader political and discursive shifts and movements. Highlighting similarities and differences across the cases allows us to make conceptual contributions to debates on variegation of neoliberalized natures, as well as to discussions of alternatives to neoliberalism and postneoliberalism. We argue that although many of these reforms are partial, and not wholly resistant to neoliberalism, they are nonetheless significant for politics and debates related to ‘alternatives.’ Apart from resisting particular aspects of earlier neoliberal reforms, they are also important to stake new discursive and policy terrain on alternative priorities and uses of water. Further, the reforms also offer points of resistance to the influence of international financial institutions, or of transnational corporations.  相似文献   

19.
Pamela D. McElwee 《Geoforum》2012,43(3):412-426
Recently in Vietnam, a coalition of international NGOs, donors and government officials have been promoting market-based forest conservation projects in the form of payments for environmental services (PES) as a win–win for both conservation and development objectives; Vietnam is now the first country in Southeast Asia with a national law on PES. This article provides a macro survey of how market-based instruments for forest conservation have expanded in Vietnam, particularly in relation to a long dominant state sector. Yet an assessment of Vietnam’s PES pilot projects indicates that they do not follow predicted orthodox “neoliberalization of nature” approaches in their use of market instruments, particularly in regards to privatization, retreat of the state, and capitalization of commodities. The article explores how it is that a strong state role in forest management can continue to dominate even in more market-oriented approaches. Finally, the article analyzes PES’s potential for success or failure in tackling the underlying causes for forest degradation. Ultimately, the article argues that PES is likely to be unable to tackle several of the key underlying causes for deforestation, namely, uneven land tenure and a lack of participation by local communities in conservation, given that PES is unlikely to be considerably different than past attempts at forest management.  相似文献   

20.
The speciation of heavy metals is very important to evaluate their environmental impact. This issue has become an interested topic many decades ago and many significative studies were carried out such as direct detecting, calculation with mathematical model represented in recent years as well as Tessier's work in 1979, BCR's work in 1993, etc. In all of them, the methods recommended by Tessier and BCR are most often used in practical study today. But it should be seen that experimental schedule and agents define these methods including BCR's method, which improved on Tessier's method, only. In many cases, there always are deviations between analytical results and real content of the speciation. Otherwise, steps of the extraction experiment are always strict and excessive in the experimental process. The method, which is fitting to extract the speciation of bioavailability and easy to assess the effect of metals in the environment, is very anticipant. In this paper, the sequential three steps schedule of speciation analysis of copper in soil and water sediment is discussed as an example based on the comparative results of experimental analysis with the schedules of BCR's (mended by Rauret et al. in 1999) and TDPA (diethylenetriamine pentacetic acid) extraction, respectively. The results from sequential three steps method and other methods recommended by prevenient work suggest that the analytical schedule of sequential three steps of separating speciation (the speciation of easy effect to life-form, the speciation available to life-form, and the speciation of no effect to life-form) is valuable for copper speciation analysis in soil and sediment. Because of easy process and saving time to evaluate its availability for life form,  相似文献   

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