| 1. |
- Rissler, Jenny, et al.
(författare)
-
Effective Density and Mixing State of Aerosol Particles in a Near-Traffic Urban Environment.
- 2014
-
Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 48:11, s. 6300-6308
-
Tidskriftsartikel (refereegranskat)abstract
- In urban environments, airborne particles are continuously emitted, followed by atmospheric aging. Also, particles emitted elsewhere, transported by winds, contribute to the urban aerosol. We studied the effective density (mass-mobility relationship) and mixing state with respect to the density of particles in central Copenhagen, in wintertime. The results are related to particle origin, morphology, and aging. Using a differential mobility analyzer-aerosol particle mass analyzer (DMA-APM), we determined that particles in the diameter range of 50-400 nm were of two groups: porous soot aggregates and more dense particles. Both groups were present at each size in varying proportions. Two types of temporal variability in the relative number fraction of the two groups were found: soot correlated with intense traffic in a diel pattern and dense particles increased during episodes with long-range transport from polluted continental areas. The effective density of each group was relatively stable over time, especially of the soot aggregates, which had effective densities similar to those observed in laboratory studies of fresh diesel exhaust emissions. When heated to 300 °C, the soot aggregate volatile mass fraction was ∼10%. For the dense particles, the volatile mass fraction varied from ∼80% to nearly 100%.
|
|
| 2. |
- Rönnlund, Maria, 1962-
(författare)
-
Demokrati och deltagande : Elevinflytande i grundskolans årskurs 7-9 ur ett könsperspektiv.
- 2011
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of this thesis is to examine the fostering of democracy in the form of pupils’ influence and participation in decision processes. The main focus is on pupils’ formal influence in lower secondary education, forms 7-9, in particular class councils and pupil councils, although informal influence is also studied. The study is ethnographic and based on observations, informal conversations and formal interviews with pupils and school staff in three Swedish schools during one school year (2007/2008). The analysis draws on theories focusing on democracy and gender (Pateman, 1970; Young, 1990, 1997, 2000a,b, 2005), and institutional aspects of education (Bernstein, 2000). The results show that the activity among the participating pupils is low, and that the councils deal with what the pupils mostly judge as unimportant and uninteresting issues. Issues related to teaching are generally seldom dealt with in the councils. A clear majority of the pupils also state that they cannot exert influence to the extent they would like, and that they find the representative systems both coercive and excluding. Still, pupils’ formal influence shows to be important as a means for democracy fostering. In particular positive participation effects are expressed in councils/groups characterised by pupil autonomy and collective community, a result that emphasises the importance of supporting pupil-governed councils and providing collective influence forms. But, the fact that a great deal of the pupils’ criticism against pupils’ influence in practice and the organization of pupils’ influence is connected to representation, indicates that alternative collective forms to a greater extent than the representative systems can promote interest and active participation among the pupils. The results also show that only a minor proportion of the pupils take active part in influence processes, both formally and informally, and that a predominant majority of the participating pupils are girls. In sum, the results lend support to the idea that active participation in some contexts and in some conditions yields certain positive participation effects. But the fact that a large group of pupils, a majority of them boys, do not participate, proves lacking achievement and inequality when it comes to democracy fostering in the form of pupils’ influence. In view of the results more groups of pupils need to be strengthened as regards influence and participation in decision processes.
|
|
