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1.
In addition to national inventories of emissions of greenhouse gases, there are inventories for most, but not all, states constituting the United States. This paper analyzes the state inventories to see if reported emissions of carbon dioxide, methane, and nitrous oxide are additive. Considerable reanalysis of the state inventories is required before they can be added to yield a larger-scale inventory. Some specific sources were considered by some states but not by others. Estimation techniques evolved over time as inventories were produced, and there are instances of both double-counting (two states reporting the same emission) and omission (neither state reporting the same emission), where interstate transfers of energy or materials occurred. Nevertheless, the inventories, when adjusted for obvious double-counting or omissions, are probably approximately additive, although it is difficult to quantify the extent to which this is true.  相似文献   

2.
Tree inventories are expensive to conduct and update, so every inventory carried out must be maximized. However, increasing the number of constituent parameters increases the cost of performing and updating the inventory, illustrating the need for careful parameter selection. This article reports the results of a systematic expert rating of tree inventories aiming to quantify the relative importance of each parameter. Using the Delphi method, panels comprising city officials, arborists, and academics rated a total of 148 parameters. The total mean score, the top ranking parameters, which can serve as a guide for decision-making at practical level and for standardization of tree inventories, were: Scientific name of the tree species and genera, Vitality, Coordinates, Hazard class, and Identification number. The study also examined whether the different responsibilities and usage of urban tree databases among organizations and people engaged in urban tree inventories affected their prioritization. The results revealed noticeable dissimilarities in the ranking of parameters between the panels, underlining the need for collaboration between the research community and those commissioning, administrating, and conducting inventories. Only by applying such a transdisciplinary approach to parameter selection can urban tree inventories be strengthened and made more relevant.  相似文献   

3.
铀在土壤中的吸附动力学   总被引:1,自引:0,他引:1  
胡立  梁斌  周敏娟 《四川环境》2011,30(1):21-25
以四川盆地红层丘陵区涪江河谷两岸广泛分布的第四系中更新统亚粘土为对象,用动态法测定了铀在该土壤中的平衡吸附量,为极低放废物的处置提供一些理论依据。研究了流速、土壤粒度及铀溶液初始浓度对土壤吸附铀的影响,并用常用的吸附动力学方程对实验数据进行了拟合。结果表明:土壤粒度小的平衡吸附量较大;流速越小、平衡吸附量越大;铀溶液的初始浓度越大,平衡吸附量越大;在用动力学方程拟合时,E lovich方程的拟合度最好;该土壤对铀的最大吸附率为61.1%,吸附性能较差。  相似文献   

4.
After the dramatic increase in prices for uranium over the 1972–1975 period, prices have declined in real terms. This article examines the future supply, demand and price trends for uranium, and predicts that a situation of excess supply will result in the 1980s, bringing a continuing decline in real prices, unless Canada and other net exporters, most importantly Australia, agree to restrict supplies in order to maintain the price of uranium at its present level in real terms. Such a policy would have substantial benefits for Canada and other net exporters of uranium.  相似文献   

5.
Greenhouse gas (GHG) emission inventories, which currently inform abatement policy discussions, are developed mostly from national scale data. Nevertheless, although the policy debate tends to take place in global and national arenas, action to abate GHG emissions is inherently within the provenance of local institutions and communities. The purpose of this paper is to examine how much information is lost by not estimating GHG emissions data at scales finer than the whole US. Such information may be critical in bridging global and local policy. Differences in the composition of GHG emission sources based on GHG emission inventories at three nested spatial scales (national, state, local) for four study sites (in Kansas, North Carolina, Ohio and Pennsylvania) are analysed, drawing upon initial results of a large collaborative study known as the 'Association of American Geographers-Global Change in Local Places (GCLP)' project. The concept of spatial sovereignty of emissions is developed to test the cross-scale reliability of emission inventories. For the test year 1990, close agreement is found in the by-gas composition of GHG emissions among national, state and local inventories. Spatial sovereignty in this case is maintained. However close agreement is not found in the by-source composition of GHG emissions among national, state and local inventories. Spatial sovereignty in this case is not maintained. Regular compilation of state and local emissions source inventories may be necessary to track important spatial and temporal deviations from national trends.  相似文献   

6.
The purpose of this article is to broaden understanding of the factors which exert major influences on prices for industrial metals beyond the widely recognized tendency for prices and inventories to move in opposite directions. Specifically, the relationship between inventory levels and price volatility is examined. In addition, the relationship between prices and production costs is also examined. A few thoughts are expressed on the relationship between prices and industry structure. The paper includes a qualitative discussion about why a link should exist between prices and production costs, a graph illustrating the relationship between prices and inventories, and econometric equations quantifying the relationship between prices, production costs and inventories.  相似文献   

7.
An important goal of biological inventories is to provide information for environmental assessments of development projects and biodiversity conservation. Likewise, computer data bases have been proposed for efficient compilation and management of biological information. However, the attributes of biological inventories and computer data bases have not been examined with respect to environmental assessments. This article presents a case study in Mexico to analyze the current limitations of biological inventories for successful environmental assessments and biodiversity conservation in developing countries. Results demonstrate that, considering the objectives of environmental assessments and information constraints, computerized biological inventories should be assembled with a minimum of record fields: taxonomic data and georeferenced collection localities. Furthermore, it is proposed that environmental assessments should become a feedback to biological inventories and an important financial support to universities and research institutions in developing countries.  相似文献   

8.
Efforts to assess forest ecosystem carbon stocks, biodiversity, and fire hazards have spurred the need for comprehensive assessments of forest ecosystem dead wood (DW) components around the world. Currently, information regarding the prevalence, status, and methods of DW inventories occurring in the world’s forested landscapes is scattered. The goal of this study is to describe the status, DW components measured, sample methods employed, and DW component thresholds used by national forest inventories that currently inventory DW around the world. Study results indicate that most countries do not inventory forest DW. Globally, we estimate that about 13% of countries inventory DW using a diversity of sample methods and DW component definitions. A common feature among DW inventories was that most countries had only just begun DW inventories and employ very low sample intensities. There are major hurdles to harmonizing national forest inventories of DW: differences in population definitions, lack of clarity on sample protocols/estimation procedures, and sparse availability of inventory data/reports. Increasing database/estimation flexibility, developing common dimensional thresholds of DW components, publishing inventory procedures/protocols, releasing inventory data/reports to international peer review, and increasing communication (e.g., workshops) among countries inventorying DW are suggestions forwarded by this study to increase DW inventory harmonization.  相似文献   

9.
World fossil energy resources are estimated at about 12,500 times 109 tons of coal equivalent (t.c.e.) of which 900 times 109 t.c.e. are classed as presently recoverable reserves. Future exploration will transform a substantial part of the resources into reserves. Coal is by far the dominant fossil energy. Oilshales and tarsands represent a large energy potential, whose utilization depends on a high energy price level and progress in production technologies. Limits in the availability of oil and gas are visible now for the first time. Low-cost, high-grade uranium reserves are also limited. However, there are large amounts of low-grade uranium resources, which might become recoverable in the future. The use of geothermal energy is currently troubled by problems of technology, costs and environment.  相似文献   

10.
This article reviews the available information on the uranium industry and the beginning of nuclear power in China. Few details of China's uranium industry have hitherto been published in the West. The broad conclusions reached are that China is faced with severe energy shortages for the foreseeable future; nuclear power will help to solve this problem but the timing and extent of its contribution are uncertain. The central question of civil nuclear policy is whether or not to use imported technology, although satisfactory development of the uranium industry probably will require foreign assistance. The principle conestraint in this regard is foreign exchange. To help overcome this problem the Chinese are now, for the first time, offering uranium on the international market.  相似文献   

11.
植物修复技术在铀矿山放射性铀污染治理中的潜在应用   总被引:1,自引:0,他引:1  
姚介  马莹  何航 《四川环境》2010,29(6):48-51
植物修复技术用于治理环境中的放射性污染,具有成本低廉、易于实施和对环境扰动小等突出优点,是近年来国内外有关研究的热点。本文简单介绍了植物修复的原理,系统地介绍了环境中铀污染的植物修复及影响修复效率的因素。分析了该技术应用于铀矿山放射性铀污染治理的可行性。  相似文献   

12.
Current economic assessment implies that there are considerable quantities of uranium available for use in present thermal reactors, albeit at very high costs. However, this method of appraisal contains a fundamental contradiction concerning the relationship between the price of electricity and the cost of uranium concentrate. Derivation of real costs with the technique of energy analysis is used to correct this basic inconsistency. This approach demonstrates that the amount of economically recoverable uranium is substantially less than previously expected. Consequently, if current forecasts of nuclear power growth are achieved then serious shortages of uranium will occur in the foreseeable future.  相似文献   

13.
This paper’s purpose is to predict China’s uranium resources demand from 2016 to 2030 based on experimental modeling. In addition, we discuss the future supply structure of China’s uranium resources by analyzing the domestic and foreign supply capacity of China’s uranium resources. According the forecast results, Chinese uranium resource demand will reach 21385 tU in 2030 under a medium scenario. Due to the poor endowment of uranium resources, China’s domestic uranium production will increase slowly. It can be calculated that the total demand of uranium resources in China during 2016–2030 will be 216581 tU, the cumulative production of domestic production will be 37900 tU, the overseas production will be 41950 tU, and the international market purchases will be 130574 tU. Hence, the cumulative degree of dependence on foreign resources is approximately 80%. China’s foreign dependence on uranium will be greater than for oil, and the situation will become extremely serious. Therefore, we put forward several suggestions to ensure the supply of China’s uranium resources: (1) strengthening mineral exploration and increasing domestic production, (2) actively operating the “going out” strategy, (3) enhancing the enterprise competition ability, and (4) establishing uranium resource reserves. By these means, China could efficiently guarantee the domestic uranium resource security and respond to the competition of India’s uranium resources demand increased.  相似文献   

14.
The US Army Land Condition-Trend Analysis (LCTA) program is a standardized method of data collection, analysis, and reporting designed to meet multiple goals and objectives. The method utilizes vascular plant inventories, permanent field plot data, and wildlife inventories. Vascular plant inventories are used for environmental documentation, training of personnel, species identification during LCTA implementation, and as a survey for state and federal endangered or threatened species. The permanent field plot data documents the vegetational, edaphic, topographic, and disturbance characteristics of the installation. Inventory plots are allocated in a stratified random fashion across the installation utilizing a geographic information system that integrates satellite imagery and soil survey information. Ground cover, canopy cover, woody plant density, slope length, slope gradient, soil information, and disturbance data are collected at each plot. Plot data are used to: (1) describe plant communities, (2) characterize wildlife and threatened and endangered species habitat, (3) document amount and kind of military and nonmilitary disturbance, (4) determine the impact of military training on vegetation and soil resources, (5) estimate soil erosion potential, (6) classify land as to the kind and amount of use it can support, (7) determine allowable use estimates for tracked vehicle training, (8) document concealment resources, (9) identify lands that require restoration and evaluate the effectiveness of restorative techniques, and (10) evaluate potential acquisition property. Wildlife inventories survey small and midsize mammals, birds, bats, amphibians, and reptiles. Data from these surveys can be used for environmental documentation, to identify state and federal endangered and threatened species, and to evaluate the impact of military activities on wildlife populations. Short- and long-term monitoring of permanent field plots is used to evaluate and adjust land management decisions.  相似文献   

15.
The National Forest Management Act (1976) specifies that multiresource inventories be conducted to provide baseline data for development and, later, monitoring of national forest management plans. This mandate entails the most ambitious and complex resource planning effort ever attempted. In this paper we evaluate the structure and use of current inventory-monitoring programs and recommend a framework for gathering data to improve national forest planning. Current national guidelines are general and provide only basic directions to forest-level planners. Forest inventories have traditionally concentrated on timber. Although these inventories are often well designed, the questions we are now asking about forest resources have outgrown these methods. Forest management is impeded by general confusion over definitions of resources and the interactions among them. We outline a simple classification scheme that centers on identification of basic ecosystem elements that can be readily measured. Furthermore, spatial and temporal scales must be considered in the design of inventory-monitoring programs. The concept of ecological indicators is reviewed, and caution is advised in their use. Inventory-monitoring programs should be goal-directed and based on as rigorous a statistical design as possible. We also review fundamental issues of variable selection, validation, and sampling bias. We conclude by developing a flexible inventory-monitoring program that is designed to provide information on individual characteristics of the environment, rather than being based on fixed definitions of resources.  相似文献   

16.
铀吸附实验研究现状   总被引:3,自引:0,他引:3  
李爽  倪师军  张成江 《四川环境》2007,26(1):77-79,84
介绍了铀吸附实验的研究现状,对吸附铀的各种载体进行了总结。目前,主要采用静态法(批示法)和动态法(柱法)进行铀的吸附实验研究。吸附铀的载体主要有粘土,金属的水合氧化物等肢体,藻类及菌类,树脂等。主要考察pH值、温度、吸附时间、阴离子、阳离子、细菌浓度、铀浓度等对吸附速率及吸附量的影响。  相似文献   

17.
A semi-dynamic leaching test was carried out for metallurgical wastes and ore samples from the uranium and copper mining industry over a 142 day period using distilled water and 0.1N NaNO(3) as solvents. Laser fluorimetry was used as the analytical technique to determine the total uranium content in the leachates. The cumulative leach fraction (CLF) of uranium release from the samples was calculated to be 0.22, 0.22, 0.07 and 0.39% for rock, uranium tailings, copper kinker ash samples and copper tailings respectively using distilled water as solvent and 0.31, 0.27, 0.05 and 0.59% for the same matrices using 0.1N NaNO(3). The release of mobile uranium fraction was very slow, being faster in the initial stage and then attained a near steady state condition. The diffusion coefficient and bulk release of uranium from the samples have been calculated. The processes governing the release of uranium from these matrices have been identified to be surface wash-off and diffusion. Hence the use of weak solvents (leach out the mobile/exchangeable fraction of uranium) under semi-dynamic conditions aids the determination of leaching parameters and identification of the leaching mechanism for mobile uranium fraction from different matrices by slow leaching processes.  相似文献   

18.
This paper reports on two efforts to develop methods for quantifying and analysing greenhouse gas emissions from local places. The International Council for Local Environmental Initiatives-Cities for Climate Protection (ICLEI-CCP) campaign and the Association of American Geographers-Global Change in Local Places (AAG-GCLP) project represent independent efforts with differing origins and objectives. There is a rich and dynamic fine structure to the causal patterns that determine the level of greenhouse gas emissions in the society. This fine structure is essentially opaque to national and state-level inventories and analyses, and yet understanding it is necessary to understanding how human communities can be organised and human enterprise structured in environmentally sustainable ways. Simplified inventory methods that account for most but not all emissions, use readily available local data and, most important, inform efforts at emission reduction are currently available for cities and could be made available for larger or more diverse local regions or areas.  相似文献   

19.
Environmental considerations have become central to future developments in the Australian mineral industry and have affected the level of federal involvement in the industry. The Environmental Impact Statement (EIS) is now an important stage in the assessment of proposed mining projects. This paper examines two major federally sponsored inquiries into Australian mining projects — Fraser Island sand-mining and the Ranger uranium project — and then discusses subsequent events and future prospects.  相似文献   

20.
The status of uranium resources for the USA for the period 1975–2000 can only be estimated within rather broad limits due to a complex interplay of the many factors involved. Minimum estimates for uranium oxide requirements to fuel light water nuclear reactors (LWRs) alone range from 2 × 106 to 2.25 × 106 tonnes U3 O8. These limits are deemed reasonable due to the unlikelihood of a firm commitment to the use of fast breeder reactors (FBRs) by the government; tentative decision dates range from 1988 to 2000 or so but, even presuming the former, the impact on uranium needs will not be felt until after 2000. A wider use of converter reactors may lighten the eventual uranium needs close to 2000. These reactors, however, were originally planned only for interim use during the change-over from LWRs to FBRs; hence their increased use will not affect the uranium demand until the next century. Present plans call for an accelerated exploration and development programme involving federal and state agencies with industry and other sources.  相似文献   

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