The Modelling of Turbulence from Traffic in Urban Dispersion Models — Part I: Theoretical Considerations

The modelling of pollutant dispersion at the street scale in an urban environment requires the knowledge of turbulence generated by the traffic motion in streets. In this paper, a theoretical framework to estimate mechanical turbulence induced by traffic in street canyons at low wind speed conditions is established. The standard deviation of the velocity fluctuations is adopted as a measure of traffic-produced turbulence (TPT). Based on the balance between turbulent kinetic energy production and dissipation, three different parameterisations for TPT suitable for different traffic flow conditions are derived and discussed. These formulae rely on the calculations of constants that need to be estimated on the basis of experimental data. One such estimate has been made with the help of a wind tunnel data set corresponding to intermediate traffic densities, which is the most common regime, with interacting vehicle wakes.     

Bayesian estimation and consequence modelling of deliberately induced domino effects in process facilities

Process facilities handling hazardous chemicals in large quantities and elevated operating conditions of temperature/pressure are attractive targets to external attacks. The possibility of an external attack on a critical installation, performed with an intention of triggering escalation of primary incidents into secondary and tertiary incidents, thereby increasing the severity of consequences needs to be effectively analysed. A prominent Petrochemical Industry located in Kerala, India was identified for studying the possibility of a deliberately induced domino effect. In this study, a dedicated Bayesian network is developed to model the domino propagation sequence in the chemical storage area of the industry, and to estimate the domino probabilities at different levels. This method has the advantage of accurately quantifying domino occurrence probabilities and identifying possible higher levels of escalations. Moreover, the combined effect from multiple units can be modelled easily and new information can be added into the model as evidences to update the probabilities. Phast (Process hazard analysis) software is used for consequence modelling to determine the impact zones of the identified primary and secondary incidents. The results of the case study show that such analyses can greatly benefit green field and brown field projects in determining the appropriate safety and security measures to be implemented or strengthened so as to reduce its attractiveness to external threat agents.     

Who is susceptible and why? An agent-based approach to assessing vulnerability to drought

In this paper, we specify susceptibility to drought from a psychology-based bottom-up perspective. On the basis of the protection motivation theory (Rippetoe and Rogers in J Pers Soc Psychol 52(3):596–604, 1987), we developed the protection-capacity model (Krömker and Mosler in Global environmental change in Alpine regions: impact, recognition, adaptation, and mitigation. Edward Elgar, Cheltenham, pp 93–112, 2002) to analyse the susceptibility with respect to the protection capacity of agents. The protection capacity is determined by the agents’ subjective assessment of the situation, which consists of the appraisal of threat, on the one hand, and the coping appraisal, on the other hand. Additionally, the protection-capacity model specifies several factors which influence the two central appraisal processes. Empirical data were collected in interviews with experts and with a total of 65 exemplarily selected households which are typical for the respective case study regions (Andhra Pradesh, India; Algarve and Alentejo, Portugal; Volgograd and Saratov, Russia). The data were analysed with the help of fuzzy set methodology. Results show that the households of the Indian region are the most susceptible when compared to those of the Russian region with ‘low’ and to households of the Portuguese region with a ‘very low’ degree of susceptibility. Moreover, we identified subgroups within the regions which are characterized by different degrees of susceptibility and a different profile of factors influencing susceptibility. Altogether, the agent-based perspective allows identifying relevant factors that need to be addressed to minimize susceptibility of the population and special subgroups. However, the results are not representative for the case study regions because of the small database. Additionally, more effort is needed to validate the findings.     

Reducing carbon emissions through improved household energy efficiency in the UK

A number of schemes to increase household energy efficiency have operated in the UK over the last 5–10 years. This paper evaluates their effectiveness in terms of reducing household energy use, carbon emissions and fuel poverty. It then draws on the quantitative results of these schemes, and published plans for their continuation, to model an extended and expanded Household Energy Efficiency Scenario to 2020, using an integrated economy–energy–environment model of the UK. The results suggest that while such schemes can play a significant role in reducing carbon emissions from households, much more ambitious schemes than those currently implemented will be necessary to offset the underlying growth in these emissions. Finally, the results are compared with the UK government's own estimates, in its Climate Change Programme, of carbon emission reductions from such schemes to 2010. The paper concludes that the government's estimates are somewhat optimistic, and that it will need substantial new policy measures beyond those already announced if its carbon reduction targets in this area are to be met. Copyright © 2002 John Wiley & Sons, Ltd.     

The consequences of land use change on nutrient exports: a regional scale assessment in south-west Victoria, Australia

Estimation of nutrient load production based on multi-temporal remotely sensed land use data for the Glenelg-Hopkins region in south-west Victoria, Australia, is discussed. Changes in land use were mapped using archived Landsat data and computerised classification techniques. Land use change has been rapid in recent history with 16% of the region transformed in the last 22 years. Total nitrogen and phosphorus loads were estimated using an export coefficient model. The analysis demonstrates an increase in modelled nitrogen and phosphorus loadings from 1980 to 2002. Whilst such increases were suspected from past anecdotal and ad-hoc evidence, our modelling estimated the magnitude of such increases and thus demonstrated the enormous potential of using remote sensing and GIS for monitoring regional scale environmental processes.     

在役工业厂房建筑维护管理分析评价

在调研了全国各区域各行业工业厂房结构安全的基础上,提出工业厂房后期运营阶段的结构安全性和可靠性需要通过科学的维修制度来保证。分析了引起工业厂房结构失检、误判的因素,建立了相应的评价指标体系,以评价企业厂房结构安全的维护管理水平。理论分析和实例评价表明,通过提高维护管理水平可以减少厂房结构失检、误判事件的发生,加强厂房的检测、维护,可以有效预防工业厂房结构渐发性事故发生,在有限成本内实现对工业厂房结构安全管理的效益最大化。     

Suspended sediment, nitrogen and phosphorus concentrations and exports during storm-events to the Tuross estuary, Australia

This paper presents a process for estimating pollutant loads from water quality data, to improve catchment-scale modelling in the region for resource management purposes. It describes a program to estimate suspended sediment, total and dissolved nitrogen and phosphorus loads to the Tuross estuary from the Tuross River catchment (1810 km(2)) of coastal southeast Australia. Event-based water quality sampling results obtained during storm events in 2005 are presented. Event 1, during July 2005 was the largest storm event in terms of peak flow for 3.5 years. Other events monitored were also in July, November and December 2005. The early July 2005 event had a flow-weighted mean suspended sediment (SS) concentration during the first 4 days of 63 mg L(-1). Of the events monitored, this was unusual as it was preceded by drought and had the largest SS concentrations (peaking at 180 mg L(-1)) during the rising-stage. In contrast, the November event had a much lower flow-weighted SS mean (28 mg L(-1)), even though peak flow magnitudes were similar. The July and November 2005 events had peak flows of 12,360 and 11,330 ML day(-1). Low-cost rising-stage siphon samplers were used to collect samples during the rapidly rising phase of these events. The use of such samplers and consideration of time-lead/lag flow adjustments, quantified using cross-correlation analysis to account for hysteresis effects, were incorporated into the load estimation techniques. The technique is a potentially useful approach for understanding relationships between water quality concentrations and flow for modelling catchment source strengths and transport processes.     

Agent based simulation of a small catchment water management in northern Thailand: Description of the CATCHSCAPE model

Due to mounting human pressure, stakeholders in northern Thailand are facing crucial natural resources management (NRM) issues. Among others, the impact of upstream irrigation management on downstream agricultural viability is a growing source of conflict, which often has both biophysical and social origins. As multiple rural stakeholders are involved, appropriate solutions should only emerge from negotiation. CATCHSCAPE is a Multi-Agent System (MAS) that enables us to simulate the whole catchment features as well as farmer’s individual decisions. The biophysical modules simulate the hydrological system with its distributed water balance, irrigation scheme management and crop and vegetation dynamics. The social dynamics are described as a set of resource management processes (water, land, cash, labour force). Water management is described according to the actual different levels of control (individual, scheme and catchment). Moreover, the model’s architecture is presented in a way that emphasises the transparency of the rules and methods implemented. Finally, one simulated scenario is described along with its main results, according to different viewpoints (economy, landscape, water management).     

Causal modelling of multivariate outcomes from developmental toxicity experiments

Exposure to developmental toxicants may cause foetal malformations, increase foetal death or resorption and reduce foetal weight. The correlations among these developmental endpoints have been reported, but their causal relationships have not been investigated. Structural equation models (path models) were applied to study the patterns of causation among the four developmental outcomes, number of viable foetuses, number of malformations, number of deaths/resorptions, and average foetal weight; these outcomes were modelled as response variables with the dose level and number of implants (litter size) modelled as independent variables. Three hypothesized path models were fitted to developmental toxicity data from a study of the herbicide 2,4,5-T exposure in mice. One model, which hypothesized that foetal weight, implicitly a mechanism such as cellular growth, affects both malformations and death/resorption (equivalently, viability) with no causation relationship between malformation and death/resorption, described data consistently well for three strains of mice. The most consistent relationship found was a strong direct effect of foetal weight on malformations, and the correlation between malformations and death/resorption (or reduced viability) was likely spurious.