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931.
基于PDCA模式的化工企业安全文化探讨 总被引:1,自引:0,他引:1
近年来,化工事故屡次发生,给国家和人民带来了巨大的经济损失.为了减少化工企业的安全生产事故,有的通过HSE管理体系降低安全事故率,有的通过危险性评价来控制危险源.从文化管理的角度探讨化工企业的安全文化建设问题,以期减少化工企业的安全生产事故. 根据安全文化管理的优势以及化工生产的特点,引入PDCA管理模型,把化工企业安全文化建设分4个阶段,系统地讨论了化工企业的安全文化建设问题,并且形成了一套化工企业的文化建设体系,可供企业参考. 相似文献
932.
Gleditsia triacanthos and the native dominant Lithraea ternifolia in montane forests of central Argentina, considering life history and demographic traits of both the alien and the native
species and different site conditions for population growth (good and bad sites). Matrix models are applied to project the
consequences of differences in vital rates for population growth. Analyzing these models helps identify which life cycle transitions
contributed most to population growth. Obtained population growth rates are considered to assess predicted rates of spread
using the reaction-diffusion (R-D) model. G. triacanthos presents many of the life history traits that confer plants high potential for invasiveness: fast growth, clonal and sexual
reproduction, short juvenile period, high seed production, and high seed germinability. These traits would ensure G. triacanthos invasive success and the displacement of the slow-growing, relatively less fecund native L. ternifolia. However, since disturbance and environmental heterogeneity complicate the invasibility pattern of G. triacanthos in these montane forests, the outcome of the invasion process is not straightforward as could be if only life history traits
were considered.
Great variation in demographic parameters was observed between populations of each species at good and bad sites. Though both
good and bad sites signified increasing or at least stable populations for G. triacanthos, for L. ternifolia bad sites represented local extinction. Analyzing the results of matrices models helps design the optimal management for
the conservation of L. ternifolia populations while preventing the invasion by G. triacanthos. The predicted asymptotic rate of spread for G. triacanthos at the good site was fourfold greater than the predicted one for L. ternifolia, although the difference was much smaller considering the bad site. The usefulness of the R-D model to study this invasion
system is discussed. 相似文献
933.
The fire simulation processes of the National Fire Management System's (NFMAS) Initial Attack Analysis (IAA) processor were
evaluated by conducting two types of sensitivity analysis: one based on a hypothetical set of data to assess IAA's outputs
under a wide range of fire input values, and the other using an actual Stanislaus National Forest database to test IAA's validity
with a real set of data. The results revealed that IAA's outputs (projected annual number of fires and area burned) were most
sensitive, in descending order, to the input values of the fire spread rate, the productivity rates of the suppression forces,
and the initial attack time, for all fuel models tested. In contrast, IAA's outputs were extremely insensitive to variations
in the fire size at discovery. Changes are necessary in the ways IAA incorporates the fire size at discovery to facilitate
the comparison among various fire detection options. The program's “escaped fire situation” analysis was found inadequate,
because the projected annual frequencies and final sizes of the simulated escaped fire events produced unacceptable results
with the Stanislaus National Forest database. Assigning final sizes to simulated escaped fires according to the fire intensity
level in which they are historically expected to occur provides a consistent way of calculation of the projected annual area
burned and the consequent cost plus net value change (C + NVC). 相似文献
934.
Fjeld RA Serkiz SM McGinnis PL Elci A Kaplan DI 《Journal of contaminant hydrology》2003,67(1-4):79-94
A conceptual model is proposed to explain the transport behavior of plutonium in laboratory columns packed with a sandy coastal soil from the U.S. Department of Energy (DOE)'s Savannah River Site. The column transport experiments involved the introduction of a finite step input of plutonium, predominately in the +5 oxidation state, into the columns followed by elution with a low-carbonate solution of 0.02 M NaClO4 at pH 3, 5, and 8. Total plutonium concentrations were measured in the effluent as a function of time. These elution profiles suggest at least two distinct physical/chemical forms of plutonium, each with a different mobility. To explain the observed behavior, the following conceptual model was evaluated: [1] equilibrium partitioning of plutonium (V) and plutonium (IV) between the aqueous and sorbed phases as defined by pH-dependent, oxidation-state specific distribution coefficients and [2] kinetic reduction of plutonium (V) to plutonium (IV) in the sorbed phase. The conceptual model was applied to the column experiments through a one-dimensional advective/dispersive mathematical model, and predictions of the mathematical model were compared with the experimental data. Overall, the model was successful in predicting some of the major features observed in the experiments. It also yielded quantitative estimates of the rate constant for surface mediated reduction of plutonium (V) to plutonium (IV) that were of the same order (10(-4) to 10(-5) s(-1)) as those calculated from batch data both for this soil and for goethite. 相似文献
935.
Optimization of the Resources Management in Fighting Wildfires 总被引:1,自引:0,他引:1
Wildfires lead to important economic, social, and environmental losses, especially in areas of Mediterranean climate where
they are of a high intensity and frequency. Over the past 30 years there has been a dramatic surge in the development and
use of fire spread models. However, given the chaotic nature of environmental systems, it is very difficult to develop real-time
fire-extinguishing models. This article proposes a method of optimizing the performance of wildfire fighting resources such
that losses are kept to a minimum. The optimization procedure includes discrete simulation algorithms and Bayesian optimization
methods for discrete and continuous problems (simulated annealing and Bayesian global optimization). Fast calculus algorithms
are applied to provide optimization outcomes in short periods of time such that the predictions of the model and the real
behavior of the fire, combat resources, and meteorological conditions are similar. In addition, adaptive algorithms take into
account the chaotic behavior of wildfire so that the system can be updated with data corresponding to the real situation to
obtain a new optimum solution. The application of this method to the Northwest Forest of Madrid (Spain) is also described.
This application allowed us to check that it is a helpful tool in the decision-making process. 相似文献
936.
Removal of NAPLs from the unsaturated zone using steam: prevention of downward migration by injecting mixtures of steam and air 总被引:1,自引:0,他引:1
Steam injection for remediation of porous media contaminated by nonaqueous phase liquids has been shown to be a potentially efficient technology. There is, however, concern that the technique may lead to downward migration of separate phase contaminant. In this work, a modification of the steam injection technology is presented, where a mixture of steam and air was injected. In two-dimensional experiments with unsaturated porous medium contaminated with nonaqueous phase liquids, it was demonstrated how injection of pure steam lead to severe downward migration. Similar experiments, where steam and air were injected simultaneously, resulted in practically no downward migration and still rapid cleanup was achieved. The processes responsible for the prevention of downward migration when injecting steam-air mixtures were analyzed using a nonisothermal multiphase flow and transport model. Hereby, three mechanisms were identified and it was demonstrated how the effectiveness of these mechanisms depended on the air-to-steam mixing ratio. 相似文献
937.
Urban waste recycling behavior: antecedents of participation in a selective collection program 总被引:1,自引:0,他引:1
ABSTRACT/
The aim of this study is to analyze the antecedents of urban waste recycling behavior. To achieve this goal, a concrete urban
waste management program was chosen. The study focuses on the Selective Collection Program (SCP) in Zaragoza, a medium-sized
city in northeastern Spain. The research starts with a conceptual model in which the variables that potentially affect recycling
behavior can be classified into two groups: incentives and barriers. Moreover, the sociodemographic characteristics of the
individuals are included in our study. Given that the proposed model requires specification of latent variables or constructs,
the analysis is based on the Structural Equation Models (SEM) methodology. The results revealed that environmental awareness,
knowledge of the environmental impact of urban waste, and the positive perception of management by local government exercise
a positive effect on individual recycling behavior, while perceived personal difficulties (space and time availability) and
distance to and from the container have a negative effect. As regards sociodemographic variables, this study found that annual
family income sustains a negative relationship with recycling behavior, while age maintains a positive one. The results obtained
clearly show the important role that the public authorities play, especially municipal governments, in achieving the waste
recycling objectives established in accordance with international legislation. 相似文献
938.
This paper presents a dynamic framework for environmental assessment when the system under study is undergoing successional
change. Successional differences between sites for which one wishes to detect a difference because of a treatment are essentially
confounding factors. We show how successional changes over the study period or resulting from differences in study site plot
ages can be factored out by developing a null model of expected behavior over time. The null model for change in state with
time is characterized in terms of a stochastic envelope around a nominal trajectory. Specific tests for the detection of trends
associated with succession are described and illustrated on example data. It is concluded that the methods developed work
particularly well for laboratory microcosm data. 相似文献
939.
H. Tong B. Thanoon G. Gudmundsson 《Journal of the American Water Resources Association》1985,21(4):651-662
ABSTRACT: This paper reports our experience in building time series models which connect the flows in two Icelandic rivers with the meteorological variables of precipitation and temperature. Two rivers with different hydrological characteristics were studied. In areas where precipitation may be either in the form of rain or snow linear models are inadequate to describe the relationship between the river and the meteorological variables. The methodology of threshold models recently developed seems to be well suited for taking into account the sharp difference in the relationship according to whether it is freezing or not. The possibility of identifying an alternative threshold variable is also explored. 相似文献
940.
Tzay-Rong Jenq Marvin L. Granstrom Shing-Fu Hsueh Christopher G. Uchrin 《Journal of the American Water Resources Association》1984,20(4):511-520
ABSTRACT A linear programming model to assess the cost-effectiveness of appropriate point and nonpoint phosphorus control measures was constructed for Carnegie Lake, an eutrophic lake located in Mercer County, New Jersey. The resultant model was tested for present and future conditions. Feasible solutions were obtained only after significant relaxation of receiving water quality standards. The high levels of point source treatment required to meet the in-stream water quality standards and the mesotrophic loading conditions suggest that a source control solution may not be feasible. 相似文献