| 1. |
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| 2. |
- Gustafsson, Berit, 1966-, et al.
(författare)
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Longitudinal pathways of engagement, social interaction skills,hyperactivity and conduct problems in preschool children
- 2021
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Ingår i: Scandinavian Journal of Psychology. - : Wiley. - 0036-5564 .- 1467-9450. ; 62:2, s. 170-184
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Tidskriftsartikel (refereegranskat)abstract
- Preschool children’s engagement/social interaction skills can be seen as aspects of positive functioning, and also act as protective aspects of functioning.On the other hand, hyperactivity/conduct problems are risk aspects that negatively affect children’s everyday functioning. Few studies have investigatedsuch orchestrated effects on mental health in young children over time. The aims of the study are rst, to identify homogeneous groups of children havingsimilar pathways in mental health between three time points. Second, to examine how children move between time points in relation to risk and protectivefactors. Alongitudinal study over 3 years, including 197 Swedish preschool children was used. Questionnaire data collected from preschool teachers.Statistical analysis using person-oriented methods with repeated cluster analyses. Children high in engagement/social skills and low in conduct problemscontinue to function well. Children with low engagement/social skills exhibiting both hyperactivity and conduct problems continue to have problems.Children with mixed patterns of protective factors and risk factors showed mixed outcomes. The stability of children’s pathways was quite high if theyexhibited many positive protective factors but also if they exhibited many risk factors. Children exhibiting a mixed pattern of protective and risk factorsmoved between clusters in a less predictable way. That stability in mental health was related to the simultaneous occurrence of either many protectivefactors or many risk factors supports the notion of orchestrated effects. The results indicate that early interventions need to have a dual focus, includingboth interventions aimed at enhancing child engagement and interventions focused on decreasing behavior problem.
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| 3. |
- Gustafsson, Berit M., 1966-, et al.
(författare)
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Hyperactivity precedes conduct problems in preschool children : a longitudinal study.
- 2018
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Ingår i: BJPsych Open. - : Cambridges Institutes Press. - 2056-4724. ; 4:4, s. 186-191
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Tidskriftsartikel (refereegranskat)abstract
- Background: Externalising problems are among the most common symptoms of mental health problems in preschool children.Aims: To investigate the development of externalising problems in preschool children over time, and the way in which conduct problems are linked to hyperactivity problems.Method: In this longitudinal study, 195 preschool children were included. Latent growth modelling of conduct problems was carried out, with gender and hyperactivity at year 1 as time-invariant predictors.Results: Hyperactivity was a significant predictor for the intercept and slope of conduct problems. Children with more hyperactivity at year 1 had more conduct problems and a slower reduction in conduct problems. Gender was a significant predictor for the slope of conduct problems.Conclusions: Children with more initial hyperactivity have less of a reduction in conduct problems over time. It is important to consider the role of hyperactivity in studies of the development of conduct problems.Declaration of interest: None.
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| 4. |
- Gustafsson, Berit M., 1966-
(författare)
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Identifying Patterns of Emotional and Behavioural Problems in Preschool children : Facilitating Early Detection
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mental health problems often debut in early childhood and may last throughout adulthood, thereby making early detection and intervention especially important. The overarching aim of the present thesis was to identify patterns of emotional and behavioural problems indicating mental health problems in preschool children. To facilitate the detection of such problems early on, one available screening instrument Strengths and Difficulties Questionnaire (SDQ), was validated. The development and interaction of externalising problems in preschool children were studied over time. Functioning and behaviour and their relations to protective and risk indicators in both environmental and personal characteristics were explored. The long-term goal was to increase knowledge about early identification of emotional and behavioural problems in preschool children in order to facilitate early intervention.In Study I (n=690), the subscales Hyperactivity and Conduct Problems were shown to be valid for children in the age group 1–3 years. A reasonable level of validity was found for the age group 4–5 years when using the original SDQ four-factor solution. The preschool teachers considered most of the SDQ items relevant and possible to rate. Based on the results of Study II (n=815), a score of ≥12 on the SDQ Total Problems Scale is recommended as a cut-off for Swedish preschool children. There were significant differences between boys and girls on all subscales except for the Emotional subscale. The Swedish norms for SDQ are to a large extent similar to findings from other European countries. Study III (n=195) showed that preschool children’s conduct problems decrease over time. Children exhibiting more initial hyperactivity (at year 1) have less reduction in conduct problems over time, i.e. the more hyperactivity early in life, the more conduct problems at year 3. In Study IV (n=197), children high in engagement and social interaction function well over time, even in the presence of hyperactivity, while children with low engagement and interaction alone or in combination with hyperactivity and conduct problems continue to have problems. Stability was related to the existence of a larger number of protective or risk indicators respectively.Taken together, this thesis has shown that the SDQ can be used to identify preschool children at risk of developing mental health problems later in life.
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| 5. |
- Järlskog, Ida, 1991, et al.
(författare)
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Traffic-related microplastic particles, metals, and organic pollutants in an urban area under reconstruction
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 774
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Tidskriftsartikel (refereegranskat)abstract
- In urban environments, particularly areas under reconstruction, metals, organic pollutants (OP), and microplastics (MP), are released in large amounts due to heavy traffic. Road runoff, a major transport route for urban pollutants, contributes significantly to a deteriorated water quality in receiving waters. This study was conducted in Gothenburg, Sweden, and is unique because it simultaneously investigates the occurrence of OP, metals, and MP on roads and in stormwater from an urban area under reconstruction. Correlations between the various pollutants were also explored. The study was carried out by collecting washwater and sweepsand generated from street sweeping, road surface sampling, and flow-proportional stormwater sampling on several occasions. The liquid and solid samples were analyzed for metals, polycyclic aromatic hydrocarbons (PAH), oxy-PAH, aliphatics, aromatics, phthalates, and MP. The occurrence of OP was also analyzed with a non-target screening method of selected samples. Microplastics, i.e. plastic fragments/fibers, paint fragments, tire wear particles (TWP) and bitumen, were analyzed with a method based on density separation with sodium iodide and identification with a stereo microscope, melt-tests, and tactile identification. MP concentrations amounted to 1500 particles/L in stormwater, 51,000 particles/L in washwater, and 2.6 × 106 particles/kg dw in sweepsand. In stormwater, washwater and sweepsand, MP ≥20 μm were found to be dominated by TWP (38%, 83% and 78%, respectively). The results confirm traffic as an important source to MP, OP, and metal emissions. Concentrations exceeding water and sediment quality guidelines for metals (e.g. Cu and Zn), PAH, phthalates, and aliphatic hydrocarbons in the C16–C35 fraction were found in most samples. The results show that the street sweeper collects large amounts of polluted materials and thereby prevents further spread of the pollutants to the receiving stormwater.
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| 6. |
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| 7. |
- Alves, C. A., et al.
(författare)
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Physical and chemical properties of non-exhaust particles generated from wear between pavements and tyres
- 2020
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Ingår i: Atmospheric Environment. - : Elsevier Ltd. - 1352-2310 .- 1873-2844. ; 224
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Tidskriftsartikel (refereegranskat)abstract
- A road simulator was used to generate wear particles from the interaction between two tyre brands and a composite pavement. Particle size distributions were monitored using a scanning mobility particle sizer and an aerosol particle sizer. Continuous measurements of particle mass concentrations were also made. Collection of inhalable particles (PM10) was conducted using a high-volume sampler equipped with quartz filters, which were then analysed for organic and elemental carbon, organic constituents and elemental composition. Tyre fragments chopped into tiny chips were also subjected to detailed organic and elemental speciation. The number concentration was dominated by particles <0.5 μm, whereas most of the mass was found in particles >0.5 μm. The emission factor from wear between pavements and tyres was of the order of 2 mg km−1 veh−1. Organic carbon represented about 10% of the PM10 mass, encompassing multiple aliphatic compounds (n-alkanes, alkenes, hopanes, and steranes), PAHs, thiazols, n-alkanols, polyols, some fragrant compounds, sugars, triterpenoids, sterols, phenolic constituents, phthalate plasticisers and several types of acids, among others. The relationship between airborne particulate organic constituents and organic matter in tyre debris is discussed. The detection of compounds that have been extensively used as biomass burning tracers (e.g. retene, dehydroabietic acid and levoglucosan) in both the shredded tiny tyre chips and the wear particles from the interaction between tyres and pavement puts into question their uniqueness as markers of wood combustion. Trace and major elements accounted for about 5% of the mass of the tyre fragments but represented 15–18% of the PM10 from wear, denoting the contribution of mineral elements from the pavement. Sulphur and zinc were abundant constituents in all samples.
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| 8. |
- Amato, Fulvio, et al.
(författare)
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Urban air quality : The challenge of traffic non-exhaust emissions
- 2014
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Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 0304-3894 .- 1873-3336. ; 275, s. 31-36
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Tidskriftsartikel (refereegranskat)abstract
- About 400,000 premature adult deaths attributable to air pollution occur each year in the European Region. Road transport emissions account for a significant share of this burden. While important technological improvements have been made for reducing particulate matter (PM) emissions from motor exhausts, no actions are currently in place to reduce the non-exhaust part of emissions such as those from brake wear, road wear, tyre wear and road dust resuspension. These "non-exhaust" sources contribute easily as much and often more than the tailpipe exhaust to the ambient air PM concentrations in cities, and their relative contribution to ambient PM is destined to increase in the future, posing obvious research and policy challenges.This review highlights the major and more recent research findings in four complementary fields of research and seeks to identify the current gaps in research and policy with regard to non-exhaust emissions. The objective of this article is to encourage and direct future research towards an improved understanding on the relationship between emissions, concentrations, exposure and health impact and on the effectiveness of potential remediation measures in the urban environment.
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| 9. |
- Andersson-Sköld, Yvonne, 1957, et al.
(författare)
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Microplastics from tyre and road wear: a literature review
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This literature review concerns microplastics from tyre and road wear caused by road traffic. As there is limited knowledge about microplastics in general, and microplastics from road traffic in particular, the Swedish Government commissioned the Swedish National Road and Transport Research Institute (VTI) to, during 2018-2020, develop and disseminate knowledge about microplastics from road traffic. The chapters in this report summarises existing knowledge about microplastics from road traffic with respect to the following aspects: sources, spread and presence; effects on and risk to the environment and human health; characteristics and chemical composition; tyre and road wear; sampling methods; analysis and sample preparation; and measures. The report also includes a chapter with overall conclusions, and a chapter about further research, development and investigation needs. The purpose of this report is to provide a basis for reducing the generation and spread of microplastics from road traffic. One aim of the report is to collate and disseminate knowledge about microplastics generated by tyre and road wear, and to review the current level of knowledge. A second aim is to identify knowledge gaps and research requirements in relation to microplastics from road traffic. This literature review is based on a review of scientific articles and reports, as well as technical literature and some information from experts and industry.
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| 10. |
- Andersson-Sköld, Yvonne, 1957-, et al.
(författare)
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Mikroplast från däck- och vägslitage : en kunskapssammanställning
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Denna kunskapssammanställning handlar om mikroplast från vägtrafikens däck- och vägslitage. Eftersom kunskapen om mikroplaster från vägtrafiken är begränsad samtidigt som däckslitage bedöms vara den största källan till utsläpp av mikroplast i Sverige, gav regeringen inom ramen för sitt arbete med plast och mikroplast Statens väg- och transportforskningsinstitut (VTI) i uppdrag att under 2018– 2020 ta fram och sprida kunskap om mikroplast från vägtrafiken. Varje kapitel i denna rapport sammanfattar befintlig kunskap om mikroplast från vägtrafiken avseende en eller flera aspekter. Dessa aspekter är: källor, spridning och förekomst; miljö- och hälsoeffekter samt risker; egenskaper och kemisk sammansättning; däck- och vägslitage; provtagningsmetoder; analys- och provberedningsmetoder samt åtgärder. Dessutom finns ett kapitel med sammanfattande slutsatser och allra sist ett kapitel om forsknings-, utvecklings- och utredningsbehov.Syftet med rapporten är att den ska utgöra ett underlag för att minska emissioner och spridning av mikroplast från vägtrafiken. Ett mål med rapporten är att sammanställa och sprida kunskap om mikroplast från däck- och vägslitage och att redogöra för nuvarande kunskapsläge. Ytterligare ett mål är att identifiera kunskaps- och forskningsbehov avseende mikroplast från vägtrafiken.Underlaget till denna kunskapssammanställning utgörs av vetenskapliga artiklar och rapporter samt facklitteratur och information från branschen och från experter.
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| 11. |
- Antonson, Hans, 1963-, et al.
(författare)
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Transportrelaterad miljökvalitet : rapport från workshop den 10-11 september 2001
- 2001
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Rapport (populärvet., debatt m.m.)abstract
- Under 10–11 september 2001 möttes 31 representanter från departement, myndigheter, forskningsfinansiärer och forskarsamhället på Scandic hotell Hasselbacken i Stockholm för att lyssna till föredragningar om och diskutera kring begreppet transportrelaterad miljökvalitet.Initiativet till workshopen togs av VTI (Statens väg- och transportforskningsinstitut) genom en delansökan i en bred ansökan kallad Tema miljökvalitet ställd till Vägverket, Banverket och KFB.Workshopens syfte var att diskutera begreppet miljökvalitet i relation till transportsektorn och att rekognosera intresset för bildandet av ett nätverk för transportrelaterad miljökvalitet. För att underlätta urvalsarbetet och göra workshopen hanterbar inbjöds ett antal gäster från departement, myndigheter, forskningsfinansiärer och forskarsamhället som alla hade relevanta kunskaper och erfarenheter inom området.
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| 12. |
- Bergqvist, J., et al.
(författare)
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Sub-glass transition annealing enhances polymer solar cell performance
- 2014
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Ingår i: Journal of Materials Chemistry A. - 2050-7488 .- 2050-7496. ; 2:17, s. 6146-6152
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Tidskriftsartikel (refereegranskat)abstract
- Thermal annealing of non-crystalline polymer:fullerene blends typically results in a drastic decrease in solar cell performance. In particular aggressive annealing above the glass transition temperature results in a detrimental coarsening of the blend nanostructure. We demonstrate that mild annealing below the glass transition temperature is a viable avenue to control the nanostructure of a non-crystalline thiophene–quinoxaline copolymer:fullerene blend. Direct imaging methods indicate that coarsening of the blend nanostructure can be avoided. However, a combination of absorption and luminescence spectroscopy reveals that local changes in the polymer conformation as well as limited fullerene aggregation are permitted to occur. As a result, we are able to optimise the solar cell performance evenly across different positions of the coated area, which is a necessary criterion for large-scale, high throughput production.
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| 13. |
- Blomqvist, Göran, 1963-, et al.
(författare)
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Damning från flygaskstabiliserade grusvägar
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Obundna vägar dammar genom trafikens framfart över dem. Sådan damning kan leda till trafiksäkerhets- och hälsorisker, olägenheter för närboende och ett accelererat nedbrytande av grusvägens slitlager. Det har funnits misstanke om att grusvägar där bärlagret stabiliserats med inblandning av flygaska skulle damma mer än konventionella grusvägar. Därför undersöktes damningen vid två fältlokaler där både asksträckor och konventionellt byggda sträckor fanns. Forskningsuppgiften var att jämföra damningen och svara på frågan om askvägar dammar mer än de konventionellt byggda vägarna. Dessutom skulle spridningen av damm till omgivningen kartläggas och förekomsten av aska i det uppvirvlade dammet detekteras. Projektet genomförs som ett samarbetsprojekt mellan VTI, SGI och Högskolan Dalarna, men även IVL har varit med i projektgruppen. Resultaten riktar sig till planerare och drift- och underhållsansvariga hos väghållare, entreprenörer och myndigheter. Fältmätningarna har innefattat såväl väletablerade som innovativa mätmetoder för bestämning av damning och sådana faktorer som påverkar damning som grusslitlagrets vattenkvot och kornstorleksfördelning.
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| 14. |
- Blomqvist, Göran, 1963-, et al.
(författare)
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Microplastics in snow in urban traffic environments
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Microplastics from road traffic, mainly from tyre wear, are globally considered to be one of the largest sources of microplastic contamination in the environment. Plastics can either be deposited in the road vicinity, at the roadside and in ditches or spread via stormwater and air to the environment and receiving water bodies. In cold climates, microplastics, as well as other traffic-related pollutants, can be temporarily stored in snow and ice on and around roads and streets. The location and concentration of these pollutants is influenced by winter operations, where ploughing and skid control contribute to redistribution, and by melting and compaction of ice and snow. This creates reservoirs of microplastics and other pollutants, which are released into stormwater or surrounding soil during thaws, but also provides an opportunity to reduce the spread of microplastics by managing snow and ice appropriately. In the present report, a case study of microplastics in snow has been carried out in the municipality of Karlstad in Sweden, to get an idea of the potential variation, both in terms of concentration and total amounts in relation to traffic and the location of the sampling in the street environment. Microplastics have been analysed by pyrolysis GC/MS to identify tyre-specific polymers in combination with eight commonly occurring plastic types. In addition, six municipalities in different parts of the country responded to a questionnaire on microplastics in snow and urban snowmelt management. The results show that microplastics related to tyre wear (rubber polymers) tend to be present in higher concentrations on and near the carriageway. Other plastics show a less clear link to traffic. Along a salted bicycle lane, an elevated level of polypropylene, from which the brush of the sweep-salting machine is made, could be detected in the surface layer of the snow. In general, knowledge about microplastics in urban snow is low in the municipalities that responded to the survey.
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| 15. |
- Bäcke, Olof, 1984, et al.
(författare)
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Enhanced thermal stability of a polymer solar cell blend induced by electron beam irradiation in the transmission electron microscope
- 2017
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Ingår i: Ultramicroscopy. - : Elsevier BV. - 1879-2723 .- 0304-3991. ; 173, s. 16-23
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Tidskriftsartikel (refereegranskat)abstract
- We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope. In areas of the film that exposed to the electron beam the nanostructure of the film remained stable, while the nanostructure in areas not exposed to the electron beam underwent large phase separation and nucleation of fullerene crystals. UV–vis spectroscopy shows that the polymer:fullerene films are stable for electron doses up to 2000 kGy.
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| 16. |
- Bäcke, Olof, 1984, et al.
(författare)
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Enhanced thermal stability of a polymer solar cell blend induced by electron beam irradiation in the transmission electron microscope
- 2017
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Ingår i: Ultramicroscopy. - : Elsevier BV. - 1879-2723 .- 0304-3991. ; 176:Spec. Issue, s. 23-30
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Tidskriftsartikel (refereegranskat)abstract
- We show by in situ microscopy that the effects of electron beam irradiation during transmission electron microscopy can be used to lock microstructural features and enhance the structural thermal stability of a nanostructured polymer:fullerene blend. Polymer:fullerene bulk-heterojunction thin films show great promise for use as active layers in organic solar cells but their low thermal stability is a hindrance. Lack of thermal stability complicates manufacturing and influences the lifetime of devices. To investigate how electron irradiation affects the thermal stability of polymer:fullerene films, a model bulk-heterojunction film based on a thiophene-quinoxaline copolymer and a fullerene derivative was heat-treated in-situ in a transmission electron microscope. In areas of the film that exposed to the electron beam the nanostructure of the film remained stable, while the nanostructure in areas not exposed to the electron beam underwent large phase separation and nucleation of fullerene crystals. UV–vis spectroscopy shows that the polymer:fullerene films are stable for electron doses up to 2000 kGy.
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| 17. |
- Bäcke, Olof, 1984, et al.
(författare)
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Mapping fullerene crystallization in a photovoltaic blend: an electron tomography study
- 2015
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 7:18, s. 8451-8456
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Tidskriftsartikel (refereegranskat)abstract
- The formation of fullerene crystals represents a major degradation pathway of polymer/fullerene bulk-heterojunction thin films that inexorably deteriorates their photovoltaic performance. Currently no tools exist that reveal the origin of fullerene crystal formation vertically through the film. Here, we show that electron tomography can be used to study nucleation and growth of fullerene crystals. A model bulk-heterojunction blend based on a thiophene-quinoxaline copolymer and a fullerene derivative is examined after controlled annealing above the glass transition temperature. We image a number of fullerene nanocrystals, ranging in size from 70 to 400 nanometers, and observe that their center is located close to the free-surface of spin-coated films. The results show that the nucleation of fullerene crystals predominately occurs in the upper part of the films. Moreover, electron tomography reveals that the nucleation is preceded by more pronounced phase separation of the blend components.
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| 18. |
- Cha, Yingying, 1989-, et al.
(författare)
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On particulate emissions from moving trains in a tunnel environment
- 2018
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Ingår i: Transportation Research Part D. - : Elsevier Ltd. - 1361-9209 .- 1879-2340. ; 59, s. 35-45
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Tidskriftsartikel (refereegranskat)abstract
- Increasing attention is being paid to airborne particles in railway environments because of their potential to adversely affect health. In this study, we investigate the contribution of moving trains to both the concentration and size distribution of particles in tunnel environments. Real-time measurements were taken with high time-resolution instruments at a railway station platform in a tunnel in Stockholm in January 2013. The results show that individual trains stopping and starting at the platform substantially elevate the particulate concentrations with a mobility diameter greater than 100 nm. Two size modes of the particulate number concentrations were obtained. A mode of around 170 nm occurs when a train moves, while the other mode peaks at about 30 nm when there is no train in the station. By using principal component analysis (PCA), three contributing sources were identified on the basis of the classification of the sizes of the particles, namely railway-related mechanical wear, suspension due to the movement of trains and sparking of electric-powered components. It is concluded that the particulate matter released by individual moving trains is a key contributor to fine particles (100–500 nm) on the railway platform in a tunnel.
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| 19. |
- Cullhed, Anna, 1966-
(författare)
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The language of passion : the order of poetics and the construction of a lyric genre 1746-1806
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The subject of this dissertation is the construction of a lyric genre in academic poetics between 1746 and 1806, in handbooks and lectures by Ch. Batteux, J. A. Schlegel, J. G. Sulzer, H. Blair, J. J. Eschenburg, J. J. Engel, A. W. Schlegel, F. W. J. Schelling, F. Ast, and F. Bouterwek. The study also aims at a reconsideration of neoclassical versus romantic poetics. The first chapter investigates the relation between tradition and discourse. It argues that poetics as a discipline relies on an ancient legacy and on contemporary legitimising discourses, such as the natural sciences, moral philosophy, or idealist philosophy. The two levels indicate sites of interplay between continuity and change. The second chapter discusses the concept of genre. It is established that the lyric genre is not dependent on a triadic system of genres. All sources provide generic enumerations, even though they represent different approaches to systematic closure. The lyric genre consists of a classical canon paired with a more changeable set of contemporary lyrics. The lyric genre is defined as the language of passion in all sources and is connected with brevity, enthusiasm, metrical freedom, and disorder. In the third chapter lyrical expression is related to concepts such as imitation, authenticity, original poetry, and religious poetry. The lyric genre vacillates between the expression of universal and individual feelings. It is argued that the identification of lyric poetry as expression does not entail that the emotions in question are to be understood as authentic.
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| 20. |
- Denby, Bruce Rolstad, et al.
(författare)
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A coupled road dust and surface moisture model to predict non-exhaust road traffic induced particle emissions (NORTRIP). Part 1 : Road dust loading and suspension modelling
- 2013
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 77, s. 283-300
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Tidskriftsartikel (refereegranskat)abstract
- Non-exhaust traffic induced emissions are a major source of particle mass in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. In this paper, Part 1, the road dust sub-model of a coupled road dust and surface moisture model (NORTRIP) is described. The model provides a generalised process based formulation of the non-exhaust emissions, with emphasis on the contribution of road wear, suspension, surface dust loading and the effect of road surface moisture (retention of wear particles and suspended emissions). The model is intended for use as a tool for air quality managers to help study the impact of mitigation measures and policies. We present a description of the road dust sub-model and apply the model to two sites in Stockholm and Copenhagen where seven years of data with surface moisture measurements are available. For the site in Stockholm, where studded tyres are in use, the model predicts the PM10 concentrations very well with correlations (R-2) in the range of R-2 = 0.76-0.91 for daily mean PM10. The model also reproduces well the impact of a reduction in studded tyres at this site. For the site in Copenhagen the correlation is lower, in the range 0.44-0.51. The addition of salt is described in the model and at both sites this leads to improved correlations due to additional salt emissions. For future use of the model a number of model parameters, e.g. wear factors and suspension rates, still need to be refined. The effect of sanding on PM10 emissions is also presented but more information will be required before this can be confidently applied for management applications. (C) 2013 Elsevier Ltd. All rights reserved.
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| 21. |
- Denby, Bruce Rolstad, et al.
(författare)
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A coupled road dust and surface moisture model to predict non-exhaust road traffic induced particle emissions (NORTRIP). Part 2 : Surface moisture and salt impact modelling
- 2013
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Ingår i: Atmospheric Environment. - : Elsevier. - 1352-2310 .- 1873-2844. ; 81, s. 485-503
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Tidskriftsartikel (refereegranskat)abstract
- Non-exhaust traffic induced emissions are a major source of airborne particulate matter in most European countries. This is particularly important in Nordic and Alpine countries where winter time road traction maintenance occurs, e.g. salting and sanding, and where studded tyres are used. Though the total mass generated by wear sources is a key factor in non-exhaust emissions, these emissions are also strongly controlled by surface moisture conditions. In this paper, Part 2, the road surface moisture submodel of a coupled road dust and surface moisture model (NORTRIP) is described.We present a description of the road surface moisture part of the model and apply the coupled model to seven sites in Stockholm, Oslo, Helsinki and Copenhagen over 18 separate periods, ranging from 3.5 to 24 months. At two sites surface moisture measurements are available and the moisture sub-model is compared directly to these observations. The model predicts the frequency of wet roads well at both sites, with an average fractional bias of -2.6%. The model is found to correctly predict the hourly surface state, wet or dry, 85% of the time. From the 18 periods modelled using the coupled model an average absolute fractional bias of 15% for PM10 concentrations was found. Similarly the model predicts the 90'th daily mean percentiles of PMio with an average absolute bias of 19% and an average correlation (R-2) of 0.49. When surface moisture is not included in the modelling then this average correlation is reduced to 0.16, demonstrating the importance of the surface moisture conditions. Tests have been carried out to assess the sensitivity of the model to model parameters and input data. The model provides a useful tool for air quality management and for improving our understanding of non-exhaust traffic emissions.
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| 22. |
- Denby, Bruce R., et al.
(författare)
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Review of Road Dust Emissions
- 2018
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Ingår i: Non-Exhaust Emissions. - : Elsevier. - 9780128117705 - 9780128117514 ; , s. 183-203
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Non-exhaust emissions from road dust, such as particulate matter (PM) available for suspension from the road surface, can be a significant contributor to traffic-related PM emissions. The sources of road dust can be many and varied and include traffic-related wear of roads, tires, and brakes, as well as a range of other sources, such as traction sanding, road salt, atmospheric deposition, migration, or entrainment from roadside dust or construction sites. The contributions vary depending on location, tire types, road surface quality, etc. Processes affecting road dust loading and emission include traffic suspension rates, driving patterns, road drainage, and vehicle spray. Importantly, meteorological conditions, such as road surface wetness, have a strong controlling impact on road dust retainment and suspension. As vehicle and road wear sources, often referred to as being direct emissions, can also be deposited on the road surface to become road dust, care should be taken in describing these sources, to avoid any double counting. © 2018 Elsevier Inc. All rights reserved.
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| 23. |
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| 24. |
- Fussell, Julia C., et al.
(författare)
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A Review of Road Traffic-Derived Non-Exhaust Particles : Emissions, Physicochemical Characteristics, Health Risks, and Mitigation Measures
- 2022
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 56:11, s. 6813-6835
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Forskningsöversikt (refereegranskat)abstract
- Implementation of regulatory standards has reduced exhaust emissions of particulate matter from road traffic substantially in the developed world. However, nonexhaust particle emissions arising from the wear of brakes, tires, and the road surface, together with the resuspension of road dust, are unregulated and exceed exhaust emissions in many jurisdictions. While knowledge of the sources of nonexhaust particles is fairly good, source-specific measurements of airborne concentrations are few, and studies of the toxicology and epidemiology do not give a clear picture of the health risk posed. This paper reviews the current state of knowledge, with a strong focus on health-related research, highlighting areas where further research is an essential prerequisite for developing focused policy responses to nonexhaust particles.
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| 25. |
- Gerlofs-Nijland, Miriam E., et al.
(författare)
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Inhalation toxicity profiles of particulate matter : a comparison between brake wear with other sources of emission
- 2019
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Ingår i: Inhalation Toxicology. - : Taylor & Francis. - 0895-8378 .- 1091-7691. ; 31:3, s. 89-98
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Tidskriftsartikel (refereegranskat)abstract
- Objective: There is substantial evidence that exposure to airborne particulate matter (PM) from road traffic is associated with adverse health outcomes. Although it is often assumed to be caused by vehicle exhaust emissions such as soot, other components may also contribute to detrimental effects. The toxicity of fine PM (PM2.5; <2.5 µm mass median aerodynamic diameter) released from brake pads was compared to PM from other sources.Materials and methods: PM2.5 of different types of brake pads (low-metallic, semi-metallic, NAO and ECE-NAO hybrid), tires and road pavement, poultry as well as the combustion of diesel fuel and wood (modern and old-fashioned stove technologies) were collected as suspensions in water. These were subsequently aerosolized for inhalation exposures. Female BALB/cOlaHsd mice were exposed for 1.5, 3, or 6 hours by nose-only inhalation up to 9 mg/m 3 .Results: Neither cytotoxicity nor oxidative stress was observed after exposure to any of the re-aerosolized PM2.5 samples. Though, at similar PM mass concentrations the potency to induce inflammatory responses was strongly dependent on the emission source. Exposure to most examined PM2.5 sources provoked inflammation including those derived from the poultry farm, wear emissions of the NAO and ECE-NAO hybrid brake pads as well as diesel and wood combustion, as indicated by neutrophil chemoattractant, KC and MIP-2 and lung neutrophil influx.Discussion and conclusions: Our study revealed considerable variability in the toxic potency of brake wear particles. Understanding of sources that are most harmful to health can provide valuable information for risk management strategies and could help decision-makers to develop more targeted air pollution regulation.
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