Abstract

Traffic congestion is one of the foremost problems confronted by the urban and suburban tenants of today. Traffic congestion increases vehicle emissions and degrades air quality. Urban planners and policy makers have consequently been always investigating choices to alleviate traffic congestion and to enhance air quality. Teleworking is one option that has received significant consideration and has been studied in the recent past. The aim of the study is to explore the relationship between teleworking, air quality and traffic in Switzerland. The analysis relies on panel individual and household level data over the period 2002-2013. We examine five main air pollutants; the sulphur dioxide (SO"sub"2"/sub"), the ground-level ozone (O"sub"3"/sub") the nitrogen dioxide (NO"sub"2"/sub"), the carbon monoxide (CO) and the particulate matter less than 10 microns (PM"sub"10"/sub"). Based on the fixed effects estimates, teleworking reduces traffic volume by 1.9 per cent. Furthermore, the reduction observed on air pollution is higher for NO"sub"2"/sub", CO and PM"sub"10"/sub" ranging between 3.3-3.7 per cent, followed by O"sub"3"/sub" at 2.3 per cent and SO"sub"2"/sub" at 2.1 per cent. According to instrumental variable (IV) approach and the two stage least squares (2SLS) method, the effect is higher ranging between 2.6-4.1 per cent. The respective reduction on traffic becomes 2.7 per cent. Overall, the main concluding remark of the study is that teleworking can be a promising tool for urban planning and development, focusing at the traffic volume reduction, and the air quality improvement. Additional policy implications of teleworking and its beneficial effects for the society are further discussed. Document type: Article

Abstract

Climate change is a major environmental threat of our time. Cities have a significant impact on greenhouse gas emissions as most of the traffic, industry, commerce and more than 50% of world population is situated in urban areas. Southern Europe is a region that faces financial turmoil, enhanced migratory fluxes and climate change pressure. The case study of Thessaloniki is presented, one of the only two cities in Greece with established climate change action plans. The effects of feasible traffic policies in year 2020 are assessed and their potential health impact is compared to a business as usual scenario. Two types of measures are investigated: operation of underground rail in the city centre and changes in fleet composition. Potential co-benefits from reduced greenhouse gas emissions on public health by the year 2020 are computed utilizing state-of-the-art concentration response functions for PM x , NO 2 and C 6 H 6 . Results show significant environmental health and monetary co-benefits when the city metro is coupled with appropriate changes in the traffic composition. Monetary savings due to avoided mortality or leukaemia incidence corresponding to the reduction in PM 10 , PM 2.5, NO 2 and C 6 H 6 exposure will be 56.6, 45, 37.7 and 1.0 million Euros respectively. Promotion of ‘green’ transportation in the city (i.e. the wide use of electric vehicles), will provide monetary savings from the reduction in PM 10 , PM 2.5 , NO 2 and C 6 H 6 exposure up to 60.4, 49.1, 41.2 and 1.08 million Euros. Overall, it was shown that the respective GHG emission reduction policies resulted in clear co-benefits in terms of air quality improvement, public health protection and monetary loss mitigation. Document type: Article

Abstract

Sustainable management strategies for securing long–term supply of rare earth elements is priority for Europe due to a complex and interlinked production chain and its dependence on Chinese export. Among rare earth elements, neodymium captured most attention due to its essential role in a wide spectrum of applications including green–energy technologies such as wind turbines and electric vehicles. Being complementary to primary production, end–of–life recycling would diversify neodymium supply, relieve the Chinese dominance on primary production and contrast the balance problem. However, neodymium recycling at end–of–life is not yet in place. In this work, we developed a dynamic material flow model to investigate neodymium stocks and flows in the EU–28 to 2016. The analysis enabled a detailed investigation of secondary sources of neodymium, which set essential boundary conditions for material recovery and recycling. We found that roughly up to 50% of the annual neodymium demand in the EU–28 could be met by domestic secondary supply, if latent recycling potentials were turned into actual capacity. Significant energy savings and GHG emissions cut could be also attained. However, product design, end–of–life collection, and scrap price issues are primary obstacles to neodymium recovery. Thus, unless going beyong those limits, establishing and maintaining a sustainable recycling chain for neodymium in the EU–28 will remain problematic.

Abstract

This paper presents the results of a recently completed study calculating the exhaust gas emissions of traffic in some parts of Russia and in the Baltic states. "br/"This is the first time that the calculation of traffic emissions in these areas has been based on actual knowledge of specific emissions rather than on norms. There are many problems concerning the availability and reliability of source material. The study dealt with seven compounds: CO, HC, NOx, TPM, SO"sub"2"/sub", Pb and CO"sub"2"/sub". Five traffic modes were studied: road, railway, air, maritime and inland-waterway traffic. Emissions were calculated using mileage, cycles, fuel consumption and specific emissions. The paper presents the total amounts of emissions in metric tonnes. The condition of the Russian transport vehicle stock and transport network is poor, and thus strongly affects the emissions. There has been a considerable decrease in total emissions due to problems in the political and economic situation. A rapid change in the vehicle stock through greatly increased vehicle imports will lower specific emissions. Total emissions will, however, increase, because mileage will increase owing to growth in the national economy and changes in the transport distribution.

Abstract

This article is concerned with application of finite element model updating to a part of a secondary feed water pipeline of a VVER type nuclear power plant. A mathematical model of the pipeline was produced with finite element method. The pipeline was subjected to modal testing in three different conditions. The results of the modal testing were then compared with those predicted with the model. This comparison revealed discrepancies between these two sets of results. It is a commonly known fact that incorrect values of parameters in a model, among other things, do cause these discrepancies. In order to improve the correlation between the measured and the predicted results and hence improve the reliability of the model, the model was subjected to finite element model updating. In this updating process, incorrect values of parameters in a model are adjusted, so that a desired level of correlation between measured and predicted results is achieved. As a result, the correlation between the measured and the predicted results was improved. The bulk of the improvement was achieved by adjusting the values of those parameters that were associated with boundary conditions of the model.

Abstract

The European Commission fourth framework programme project ‘Assessment of passive safety injection systems of advanced light water reactors’ involved experiments on the PACTEL test facility and computer simulations of selected experiments. The experiments focused on the performance of passive safety injection systems (PSIS) of advanced light water reactors (ALWRs) in small break loss-of-coolant accident (SBLOCA) conditions. The PSIS consisted of a core make-up tank (CMT) and two pipelines. A pressure balancing line (PBL) connected the CMT to one cold leg. The injection line (IL) connected it to the downcomer. The project involved 15 experiments in three series. The experiments provided information about condensation and heat transfer processes in the CMT, thermal stratification of water in the CMT, and natural circulation flow through the PSIS lines. The project included validation of three thermal-hydraulic computer codes (APROS, CATHARE and RELAP5). The analyses showed the codes are capable of simulating the overall behaviour of the transients. The codes predicted accurately the core heatup, which occurred when the primary coolant inventory was reduced so much that the core top became free of water. The detailed analyses of the calculation results showed that some models in the codes still need improvements. Especially, further development of models for thermal stratification, condensation and natural circulation flow with small driving forces would be necessary for accurate simulation of the phenomena in the PSIS.

Abstract

systematic assessment, based on an extensive literature review, of the impact of gaps and uncertainties on the results of quantitative risk assessments (QRAs) for CO2 pipelines is presented. Sources of uncertainties that have been assessed are: failure rates, pipeline pressure, temperature, section length, diameter, orifice size, type and direction of release, meteorological conditions, jet diameter, vapour mass fraction in the release and the dose-effect relationship for CO2. A sensitivity analysis with these parameters is performed using release, dispersion and impact models. The results show that the knowledge gaps and uncertainties have a large effect on the accuracy of the assessed risks of CO2 pipelines. In this study it is found that the individual risk contour can vary between 0 and 204m from the pipeline depending on assumptions made. In existing studies this range is found to be between "1m and 7.2km. Mitigating the relevant risks is part of current practice, making them controllable. It is concluded that QRA for CO2 pipelines can be improved by validation of release and dispersion models for high-pressure CO2 releases, definition and adoption of a universal dose-effect relationship and development of a good practice guide for QRAs for CO2 pipelines. © 2009 Elsevier B.V.

Abstract

Complex interactions existing between water distribution systems' materials and water can cause a reduction in water quality and unwanted changes in materials, aging or corrosion of materials and formation of biofilms on surfaces. Substances leaching from pipe materials and water fittings, as well as the microbiological quality of water and formation of biofilms were evaluated by applying a Living Lab theme i.e. a research in a real life setting using a full scale system during its first year of operation. The study site was a real office building with one part of the building lined with copper pipes, the other with cross-linked polyethylene (PEX) pipes thus enabling material comparison; also differences within the cold and hot water systems were analysed. It was found that operational conditions, such as flow conditions and temperature affected the amounts of metals leaching from the pipe network. In particular, brass components were considered to be a source of leaching; e. g. the lead concentration was highest during the first few weeks after the commissioning of the pipe network when the water was allowed to stagnate. Assimilable organic carbon (AOC) and microbially available phosphorus (MAP) were found to leach from PEX pipelines with minor effects on biomass of the biofilm. Cultivable and viable biomass (heterotrophic plate count (HPC), and adenosine triphosphate (ATP)) levels in biofilms were higher in the cold than in the hot water system whereas total microbial biomass (total cell count (DAPI)) was similar with both systems. The type of pipeline material was not found to greatly affect the microbial biomass or Alpha-, Beta- and Gammaproteobacteria profiles (16s rRNA gene copies) after the first one year of operation. Also microbiological quality of water was found to deteriorate due to stagnation.

Abstract

The introduction of local scale analysis in Integrated Assessment Modelling (IAM) requires an evaluation of road transport emission factors and local scale air quality models. The comparison of PM10 and PM2.5 over NOx delta (street level minus background) concentration ratios against emission ratio estimates, confirms the appropriateness of the COPERT methodology. The comparison also reveals the non-exhaust coarse fraction source in Stockholm to be three times the fine fraction in summer, but seven times that in winter. In London it is twice the fine fraction. The model intercomparison study shows that simple street canyon models can be sufficient for use in IAM. Copyright © 2009, Inderscience Publishers.