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31.
Chris J. Matthews David B. Newton Roger D. Braddock Bofu Yu 《Environmental Modeling and Assessment》2007,12(1):27-41
Recently, the New Morris Method has been presented as an effective sensitivity analysis tool for mathematical models. The
New Morris Method estimates the sensitivity of an output parameter to a given set of input parameters (first-order effects)
and the extent these parameters interact with each other (second-order effects). This method requires the specification of
two parameters (runs and resolution) that control the sampling of the output parameter to determine its sensitivity to various
inputs. The criteria for these parameters have been set on the analysis of a well-behaved analytical function (see Cropp and
Braddock, Reliab. Eng. Syst. Saf. 78:77–83, 2002), which may not be applicable to other physical models that describe complex
processes. This paper will investigate the appropriateness of the criteria from (Cropp and Braddock, 2002) and hence the effectiveness
of the New Morris Method to determine the sensitivity behaviour of two hydrologic models: the Soil Erosion and Deposition
System and Griffith University Representation of Urban Hydrology. In the first case, this paper will separately analyse the
sensitivity of an output parameter on a set of input parameters (first- and second-order effects) for each model and discuss
the physical meaning of these sensitivities. This will be followed by an investigation into the sampling criteria by exploring
the convergence of the sensitivity behaviour for each model as the sampling of the parameter space is increased. By comparing
these trends to the convergence behaviour from Cropp and Braddock (2002), we will determine how well the New Morris Method
estimates the sensitivity for each model and whether the sampling criteria are appropriate for these models. It will be shown
that the New Morris Method can provide additional insight into the functioning of these models, and that, under a different
metric, the sensitivity behaviour of these models does converge confirming the sampling criteria set by Cropp and Braddock. 相似文献
32.
Rosqvist S Johannesson G Lindh CH Jönsson BA 《Journal of environmental monitoring : JEM》2000,2(2):155-160
Hexahydrophthalic anhydride (HHPA) and methylhexahydrophthalic anhydride (MHHPA) are two highly allergenic compounds used in the chemical industry. A method was developed for quantification of protein adducts of HHPA and MHHPA in human plasma. The plasma was dialysed and the anhydrides were hydrolysed from the proteins at mild acidic conditions. The released hexahydrophthalic acid (HHP acid) and methylhexahydrophthalic acid (MHHP acid) were purified by reversed solid phase extraction followed by derivatisation with pentafluorobenzyl bromide. The derivatives were analysed using GC-MS in negative ion chemical ionisation mode with ammonia as moderating gas. As internal standards, deuterium labelled HHP and MHHP acids were used. The detection limits were 0.06 pmol mL(-1) plasma for HHP acid and 0.03 pmol mL(-1) plasma for MHHP acid. The between-day precisions for HHP acid were 18% at 0.3 pmol mL(-1) and 8% at 4 pmol mL(-1). For MHHP acid, the precisions were 13% at 0.3 pmol mL(-1) and 9% at 4 pmol mL(-1). There were strong correlations (r=0.94 for HHPA and 0.99 for MHHPA) between total plasma protein adduct concentrations and serum albumin adduct levels. Workers exposed to time-weighted average air levels of HHPA between < 1 and 340 microg m(-3) and between 2 and 160 microg m(-3) for MHHPA had plasma adduct levels between the detection limits of the methods and 8.40 and 19.0 pmol mL(-1), respectively. 相似文献
33.
Development and validation of methods for environmental monitoring of cyclophosphamide in workplaces
Methods to monitor contamination of workplaces with antineoplastic drugs have been developed and validated. Cyclophosphamide (CP) was used as a model compound as it is one of the most commonly used antineoplastic drugs. A wipe sampling method to detect contamination with CP at surfaces was developed. A personal air sampling method to sample gas and vapour on solid sorbent tubes and particles with filters was also developed. Wipe and filter samples were extracted and sorbent samples were eluted, all with ethyl acetate. The samples were analysed with liquid chromatography tandem mass spectrometry. (2)H(6)-labelled cyclophosphamide was used as an internal standard. The between-day precision was 2-5% for wipe samples, 4-6% for sorbent samples and 3-8% for filter samples. The limit of detection was 0.02 ng CP per sample for the wipe and filter methods and 0.03 ng CP per sample for the solid sorbent method. Wipe sampling on surfaces made of different materials resulted in mean recoveries between 78-106%. The desorption recovery was between 97-102% for the wipe samples, 97% for the sorbent samples and 101% for the filter samples. Samples were stable for up to 2 months at 5 degrees C and -20 degrees C and for about 2 d at room temperature. The developed methods were applied to the measurement of contamination with CP in a hospital pharmacy. Trace amounts of CP, 1.3 and 1.4 ng, were detected on surfaces in the pharmacy. 相似文献
34.
A method was developed for the determination of benzene in urine. The sample was pumped through the donor channel of a membrane extraction unit with a micro-porous membrane, separating the donor channel from an identical acceptor channel purged with nitrogen. The analyte reached the acceptor channel by diffusion through the membrane and was then swept by the carrier to a solid sorbent tube, where it was trapped. The analyte was subsequently thermally desorbed and analyzed by gas chromatography (GC) with mass selective detection (MS). After optimization, the recovery was close to quantitative, or 95%. Purging the membrane unit with pure water in between the samples eliminated any memory effects. The linearity was good in the concentration range examined (20-4000 ng l(-1)), with a correlation coefficient of 0.9996. The repeatability at 50 ng l(-1) and 400 ng l(-1) was 1.4% and 1.2%, respectively. The limit of detection was 12 ng l(-1) and the limit of quantification 35 ng l(-1). This enables assessment of benzene exposures of occupationally exposed subjects, of smokers and the majority of the general population. The developed method can be easily automated. 相似文献
35.
Charles S. Tapiero 《Environmental Modeling and Assessment》2005,9(4):201-206
Conclusion In this paper we have considered a specific environmental game emphasizing both control-prevention efforts and the propensity to pollute by a firm which adopts a given pollution abatement technology. A random payoff game was constructed and solved under a risk neutral assumption and quadratic utilities for both the firm and the environmental controller. The game thus defined, provides a wide range of interpretations and potential approaches for selecting a control-inspection policies to prevent environmental risks. There are of course many facets to this problem, which could be considered and have not been considered in sufficient depth. For example, more complex control mechanisms and liabilities, the effects of insurance and risk sharing, the application of cooperative efforts and subvention of pollution abatement investments (through tax incentives and their like), etc. have not been considered [5,7]. These are topics for further research. The basic presumption of this paper is that it is very difficult to fully enforce pollution prevention by firms, as a result, some controls are needed to ensure that firms be controlled so that appropriate efforts are carried. 相似文献
36.
B. Beck-Friis M. Pell U. Sonesson H. Jönsson H. Kirchmann 《Environmental monitoring and assessment》2000,62(3):317-331
Composting can be a source of N2O andCH4 production. In this investigation, differentcompost heaps of organic household waste weremonitored with the focus on potential formation ofCH4 and N2O in the heaps and emission ofthese gases from the heaps. The studied compost heapshad different compost ages, turning intervals andcompost sizes. The analysed compost gases containedbetween 1–3421 L of N2O-N L-1 and 0–470 mL of CH4 L-1. The emission rates ofN2O and CH4 from the compost heaps werebetween 1–1464 mg N2O m-2 day-1 and0–119 000 mg CH4 m-2 day-1. These verylarge differences in compost gas composition andemission indicate the importance of compostmanagement. The results also give an understanding ofwhere in the composting process an increasing emissionof N2O and CH4 can occur. 相似文献
37.
38.
Gottfried Tappeiner Ulrike Tappeiner Janette Walde 《Environmental Modeling and Assessment》2007,12(4):253-256
The complexity of today’s research problems increasingly demands that scientists move beyond the confines of their own discipline.
In this special issue, the basics of a transdisciplinary framework are established and problems analyzed in a specific discipline
are successfully integrated in this transdisciplinary network. The intent has been to go beyond only statements about the
importance of enabling early stage researchers to work across disciplinary boundaries, and to show that important discoveries
are being made at the intersection of disciplines. Embedding various research projects in a more global framework can meet
the demands of an interdisciplinary or transdisciplinary approach (especially for early stage researchers) and contribute
significantly to sustainable research. 相似文献
39.
A study on the orbit of air temperature movement 总被引:1,自引:0,他引:1
Zong-Chang Yang 《Environmental Modeling and Assessment》2007,12(2):131-143
In this paper, we describe an air temperature movement by mapping its time series to the polar coordinates: the value of the
time series is plotted on the radial coordinate and the time on the angular coordinate. In this way, both the yearly and daily
air temperature movements from five different locations of China are used to demonstrate that, in an intuitionistic view,
air temperature movement is neither random nor chaotic, but has its own orbit. We then propose an elliptic orbit model for
the air temperature movement. Our proposed model provides quite good results when it is applied to the evaluation of yearly
air temperature movements in eight locations in various parts of the world, and the evaluation of daily air temperature movements
in five locations in Hunan Province of China on December 17, 2005. Results show that our approach provides a concise and helpful
model for air temperature analysis. 相似文献
40.
Specific PCR amplification and probe hybridization techniques were applied to examine the compositions of airborne fungi in samples from three different environments. The results from microscopic and CFU counting were compared to those of the molecular-based detections. The detection sensitivity for PCR amplifications was 9 to 73 spores and 1.3 to 19.3 CFUs per PCR reaction. The hybridization detection limit was 2 to 4 spores and 0.2 to 1.2 CFU. The hybridization method was more sensitive than PCR amplification and showed less variation among samples. Using specific PCR primers and probes we identified the presence of several fungal groups and species in the air samples. Specific detections through probe hybridization to PCR products amplified with universal or group-specific fungal primers have promising applications in the examination of air samples for environmental monitoring. 相似文献