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961.
研究了在 80~ 1 0 0℃条件下制备样品 ,利用催化光度法间接测得鸡蛋中碘的含量。在 0~ 0 .0 2 1 mg/ L内符合比耳定律 ,摩尔吸光系数达 2 .0 3× 1 0 5L.mol- 1 .cm- 1。可用于其它食品中微量碘的测定。 相似文献
962.
阐述了清洁生产是可持续局长战略思想的具体体现,是实现可持续发展战略的必由之路。并提出了推行清洁生产的一些建议和设想。 相似文献
963.
The Role of Abatement Costs in GHG Permit Allocations: A Global Stabilization Scenario Analysis 总被引:1,自引:0,他引:1
Kathleen Vaillancourt Richard Loulou Amit Kanudia 《Environmental Modeling and Assessment》2008,13(2):169-179
Our objective is to propose permit allocation schemes that lead to a fair distribution of the net abatement cost among regions
in a global greenhouse gas (GHG) stabilization scenario. We use a detailed technology-based energy model, World-MARKAL, to
determine efficient abatement decisions, and to calculate the regional gross abatement costs (before permit allocation and
trading). The net abatement costs are then calculated and used for different permit allocation schemes. 相似文献
964.
Yang Y He Z Lin Y Phlips EJ Yang J Chen G Stoffella PJ Powell CA 《Journal of environmental monitoring : JEM》2008,10(4):508-516
Water quality throughout south Florida has been a major concern for many years. Nutrient enrichment in the Indian River Lagoon (IRL) is a major surface water issue and is suggested as a possible cause of symptoms of ecological degradation. In 2005-06, water samples were collected weekly from seven sites along Ten Mile Creek (TMC), which drains into the Indian River Lagoon, to investigate and analyze spatial and temporal fluctuations of nutrients nitrogen (N) and phosphorus (P). The objective of this study was to understand the relationships among chlorophyll a concentration, nutrient enrichment and hydrological parameters in the surface water body.High median concentrations of total P (TP, 0.272 mg L(-1)), PO4-P (0.122 mg L(-1)), and dissolved total P (DTP, 0.179 mg L(-1)); and total N (TN, 0.988 mg L(-1)), NO3(-)-N (0.104 mg L(-1)), NH4+-N (0.103 mg L(-1)), and total Kjeldahl N (TKN, 0.829 mg L(-1)), were measured in TMC. The concentrations of TP, PO4-P, DTP, TN, NO3(-)-N, NH4+-N, and TKN were higher in summer and fall than in winter and spring. However, chlorophyll a and pheophytin concentrations during this period in TMC varied in the range of 0.000-60.7 and 0.000-17.4 microg L(-1), with their median values of 3.54 and 3.02 microg L(-1), respectively. The greatest mean chlorophyll a (10.3 microg L(-1)) and pheophytin (5.71 microg L(-1)) concentrations occurred in spring, while the lowest chlorophyll a (1.49 microg L(-1)) and pheophytin (1.97 mug L(-1)) in fall. High concentrations of PO4-P (>0.16 mg L(-1)), DTP (>0.24 mg L(-1)), NO3(-)-N (>0.15 mg L(-1)), NH4+-N (>0.12 mg L(-1)), and TKN (>0.96 mg L(-1)), occurred in the upstream of TMC, while high concentrations of chlorophyll a (>6.8 mug L(-l)) and pheophytin (>3.9 microg L(-l)) were detected in the downstream of TMC. The highest chlorophyll a (11.8 mug L(-l)) and pheophytin (6.06 microg L(-l)) concentrations, however, were associated with static and open water conditions. Hydrological parameters (total dissolved solid, electrical conductivity, salinity, pH, and water temperature) were positively correlated with chlorophyll a and pheophytin concentrations (P < 0.01) and these factors overshadowed the relationships between N and P concentrations and chlorophyll a under field conditions. Principal component analysis and the ratios of DIN/DP and TN/TP in the water suggest that N is the limiting nutrient factor for phytoplankton growth in the TMC and elevated N relative to P is beneficial to the growth of phytoplankton, which is supported by laboratory culture experiments under controlled conditions. 相似文献
965.
Because of fast urban sprawl, land use competition, and the gap in available funds and needed funds, municipal decision makers
and planners are looking for more cost-effective and sustainable ways to improve their sewer infrastructure systems. The dominant
approaches have turned to planning the sanitary sewer systems within a regional context, while the decentralized and on-site/cluster
wastewater systems have not overcome the application barriers. But regionalization policy confers uncertainties and risks
upon cities while planning for future events. Following the philosophy of smart growth, this paper presents several optimal
expansion schemes for a fast-growing city in the US/Mexico borderlands—the city of Pharr in Texas under uncertainty. The waste
stream generated in Pharr is divided into three distinct sewer sheds within the city limit, including south region, central
region, and north region. The options available include routing the wastewater to a neighboring municipality (i.e., McAllen)
for treatment and reuse, expanding the existing wastewater treatment plant (WWTP) in the south sewer shed, and constructing
a new WWTP in the north sewer shed. Traditional deterministic least-cost optimization applied in the first stage can provide
a cost-effective and technology-based decision without respect to associated uncertainties system wide. As the model is primarily
driven by the fees charged for wastewater transfer, sensitivity analysis was emphasized by the inclusion of varying flat-rate
fees for adjustable transfer schemes before contracting process that may support the assessment of fiscal benefits to all
parties involved. Yet uncertainties might arise from wastewater generation, wastewater reuse, and cost increase in constructing
and operating the new wastewater treatment plant simultaneously. When dealing with multiple sources of uncertainty, the grey
mixed integer programming (GIP) model, formulated in the second stage, can further allow all sources of uncertainties to propagate
throughout the optimization context, simultaneously leading to determine a wealth of optimal decisions within a reasonable
range. Both models ran for three 5-year periods beginning in 2005 and ending in 2020. The dynamic outputs of this analysis
reflect the systematic concerns about integrative uncertainties within this decision analysis, which enable decision makers
and stakeholders to make all-inclusive decisions for sanitary sewer system expansion in an economically growing region. 相似文献
966.
Matteo Carpentieri Paolo Giambini Andrea Corti 《Environmental Modeling and Assessment》2008,13(3):415-429
Several wind tunnel experiments of tracer dispersion from reduced-scale landfill models are presented in this paper. Different
experimental set-ups, hot-wire anemometry, particle image velocimetry and tracer concentration measurements were used for
the characterisation of flow and dispersion phenomena nearby the models. The main aim of these experiments is to build an
extensive experimental data set useful for model validation purposes. To demonstrate the potentiality of the experimental
data set, a validation exercise on several mathematical models was performed by means of a statistical technique. The experiments
highlighted an increase in pollutant ground level concentrations immediately downwind from the landfill because of induced
turbulence and mean flow deflection. This phenomenon turns out to be predominant for the dispersion process. Tests with a
different set-up showed an important dependence of the dispersion phenomena from the landfill height and highlighted how complex
orographic conditions downwind of the landfill do not affect significantly the dispersion behaviour. Validation exercises
were useful for model calibration, improving code reliability, as well as evaluating performances. The Van Ulden model proved
to give the most encouraging results. 相似文献
967.
We present a new mathematical programming framework that is adaptable to a variety of spatially explicit landscape problems
in environmental investment, conservation, and land-use planning, transport planning, and agriculture. As part of capturing
spatial interdependencies, the framework considers decision variables at two levels, finely spaced grid cells and landholdings.
We applied the framework to an environmental investment problem using objective functions representing biodiversity and carbon
sequestration. We also tested the model to optimize the path of a road through part of the landscape. Using the Nambucca case
study in eastern Australia, we applied a hybrid greedy randomised adaptive search procedure (GRASP) to find solutions to the
model. 相似文献
968.
Felix Deutsch Jean Vankerkom Liliane Janssen Filip Lefebre Clemens Mensink Frans Fierens Gerwin Dumont Edward Roekens 《Environmental Modeling and Assessment》2008,13(3):431-437
The European Operational Smog (EUROS) integrated air quality modelling system has been extended to model fine particulate
matter (PM). From an extended literature study, the Caltech Atmospheric Chemistry Mechanism and the Model of Aerosol Dynamics,
Reaction, Ionisation and Dissolution were selected and recently coupled to EUROS. Currently, modelling of mass and chemical
composition of aerosols in two size fractions (PM2.5 and PM10–2.5) is possible. The chemical composition is expressed in terms of seven components: ammonium, nitrate, sulphate, elementary
carbon, primary inorganic compounds, primary organic compounds and secondary organic compounds. Calculated PM10 concentrations and chemical composition are presented for two summer months of the year 2003 (1 July to 31 August). 相似文献
969.
We describe the development and parameterization of a grid-based model of African savanna vegetation processes. The model
was developed with the objective of exploring elephant effects on the diversity of savanna species and structure, and in this
formulation concentrates on the relative cover of grass and woody plants, the vertical structure of the woody plant community,
and the distribution of these over space. Grid cells are linked by seed dispersal and fire, and environmental variability
is included in the form of stochastic rainfall and fire events. The model was parameterized from an extensive review of the
African savanna literature; when available, parameter values varied widely. The most plausible set of parameters produced
long-term coexistence between woody plants and grass, with the tree–grass balance being more sensitive to changes in parameters
influencing demographic processes and drought incidence and response, while less sensitive to fire regime. There was considerable
diversity in the woody structure of savanna systems within the range of uncertainty in tree growth rate parameters. Thus,
given the paucity of height growth data regarding woody plant species in southern African savannas, managers of natural areas
should be cognizant of different tree species growth and damage response attributes when considering whether to act on perceived
elephant threats to vegetation. 相似文献
970.
Environmental security is one of the fundamental requirements of our well being. However, it still remains a major global challenge. Therefore, in addition to reducing and/or eliminating the amounts of toxic discharges into the environment, there is need to develop techniques that can detect and monitor these environmental pollutants in a sensitive and selective manner to enable effective remediation. Because of their integrated nature, biosensors are ideal for environmental monitoring and detection as they can be portable and provide selective and sensitive rapid responses in real time. In this review we discuss the main concepts behind the development of biosensors that have most relevant applications in the field of environmental monitoring and detection. We also review and document recent trends and challenges in biosensor research and development particularly in the detection of species of environmental significance such as organophosphate nerve agents, heavy metals, organic contaminants, pathogenic microorganisms and their toxins. Special focus will be given to the trends that have the most promising applications in environmental security. We conclude by highlighting the directions towards which future biosensors research in environmental security sector might proceed. 相似文献