| 1. |
- Bodvik, Rasmus, et al.
(författare)
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Aggregation and network formation of aqueous methylcellulose and hydroxypropylmethylcellulose solutions.
- 2010
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Ingår i: Colloids and Surfaces A. - : Elsevier. - 0927-7757 .- 1873-4359. ; 354:1-3, s. 162-171
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Tidskriftsartikel (refereegranskat)abstract
- Solution properties of methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) have been investigated as a function of temperature and concentration using a broad range of experimental techniques. Novelties include the extensive comparison between MC and HPMC solutions as well as the combination of techniques, and the use of Cryo transmission electron microscopy (Cryo-TEM). The correlation between rheology and light scattering results clearly demonstrates the relation between viscosity change and aggregation. Cryo-TEM images show the network structures formed. Viscosity measurements show that for both MC and HPMC solutions sudden changes in viscosity occur as the temperature is increased. The onset temperature for these changes depends on polymer concentration and heating rate. For both MC and HPMC solutions the viscosity on cooling is very different compared to on heating, demonstrating the slow equilibration time. The viscosity changes in MC and HPMC solutions are dramatically different; for MC solutions the viscosity increases by several orders of magnitude when a critical temperature is reached, whereas for HPMC solutions the viscosity decreases abruptly at a given temperature, followed by an increase upon further heating. Light and (SAXS) small-angle X-ray scattering shows that the increase in viscosity, for MC as well as for HPMC solutions, is due to extensive aggregation of the polymers. Light scattering also provides information on aggregation kinetics. The SAXS measurements allow us to correlate aggregation hysteresis to the viscosity hysteresis, as well as to extract some structural information. Cryo-TEM images give novel information that a fibrillar network is formed in MC solutions, and the strong viscosity increase occurs when this network spans the whole solution volume. For HPMC solutions the behaviour is more complex. The decrease in viscosity can be related to the formation of compact objects, and the subsequent increase to formation of fibrillar structures, which are more linear and less entangled than for MC.
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| 2. |
- Stenseke, Marie, et al.
(författare)
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Kris i naturen – vår existens har blivit sårbar
- 2019
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Ingår i: Svenska Dagbladet, Stockholm. - 1101-2412.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Fler arter än någonsin i mänsklighetens historia hotas av utrotning och den biologiska mångfalden lokalt har förändrats kraftigt i en stor del av världens ekosystem. Grundläggande förändringar behövs både i samhället och för individer, för att bromsa den negativa trenden, skriver en rad debattörer.
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| 3. |
- Raffoul, Alexandre, et al.
(författare)
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En fossilfri ekonomi för en säkrare värld
- 2022
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Ingår i: Dagens ETC. - 1652-8980. ; , s. 5-5
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Nu idag uppmanar de unga från Fridays for future oss alla över hela världen att strejka och demonstrera för klimaträttvisa. Det finns ett samband mellan just rättvisa och internationellt samarbete kring klimatkrisen och kriget i Ukraina, en koppling mellan fossilbränsleekonomin och global otrygghet.
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| 4. |
- Bergström, Hans, et al.
(författare)
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Wind power in cold climates : Ice mapping methods
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In the Vindforsk V-313 project “Vindkraft i kallt klimat” the goal was to arrive at a methodology to construct a high resolution (1x1 km2) climatology of icing on wind power turbines. This is a very demanding task since observations of icing on instruments have only been routinely available in Sweden during three winter seasons and at a dozen locations. The term climatology in classical meteorology means statistics over 30 years of data, and usually in the form of direct or indirect measurements. Examples are mean temperatures (annual, monthly, maximum etc.), number of frost days, growing season, variability, number of days of precipitation, mean winds, cloudiness, solar radiation, to name a few.In the project researchers from Uppsala University, WeatherTech Scandinavia, and SMHI have been collaborating. Observations have been analysed and state-of-the-art numerical weather prediction models have been applied in case studies and tested in several sensitivity studies. Extensive model verification has been carried out. Modelled ice load and estimated production losses were also compared to measurements. The question of how to arrive at a method using only a few years to represent the long-term climatology was addressed and several methods were tested.The project has shed light on the uncertainties in modelling ice load and icing climate. The end results not only depend on which mesoscale model that is used but also on how the model is set up. In order to improve the models more accurate measurements of ice load is needed. Observations of liquid cloud water content and droplet size distributions could also be of significant value to better understand why the ice load models fail in capturing the observed ice load.
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| 5. |
- Fransson, Emma, 1973-, et al.
(författare)
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Exploring salivary cortisol and recurrent pain in mid-adolescents living in two homes
- 2014
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Ingår i: BMC Psychology. - : Springer Science and Business Media LLC. - 2050-7283. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Each year, around 50.000 children in Sweden experience a separation between their parents. Joint physical custody (JPC), where the child alternates homes between the parents for about equal amount of time, has become a common living arrangement after parental separation. Children in two homes could benefit from everyday contact with both parents and access to both parents' financial resources. However, children could experience stress from being constantly moving and potentially exposed to parental conflicts. Still, studies on JPC and biological functioning related to stress, are lacking. The aim of this study was to investigate how living arrangements (intact family/JPC) relate to HPA-axis activity and recurrent pain in mid-adolescents.METHODS: Mid-adolescents (106 girls and 51 boys) provided demographic details, self-reports of recurrent pain (headache, stomachache, neck/shoulder and back pain) and salivary samples. Salivary cortisol samples were collected: 1) immediately at awakening, 2) +30 minutes, 3) +60 minutes, and 4) at 8 p.m. The cortisol awakening response (CAR) was computed using an established formula. Additionally, the diurnal decline between the waking and 8 p.m. samples was computed.RESULTS: Hierarchical multiple regressions showed that living arrangements (intact family/JPC) was not associated with morning cortisol (CAR), the diurnal cortisol decline or with recurrent pain. However, sex was a significant predictor of both cortisol measures and recurrent pain with girls exhibiting a higher cortisol awakening response and a greater diurnal decline value as well as reporting more recurrent pain than did boys.CONCLUSIONS: Living arrangements were not associated with HPA-axis activity or recurrent pain in this group of well-functioning mid-adolescents. Although this study is the first to investigate how living arrangements relate to HPA-axis functioning and additional studies are needed, the tentative findings suggest that these mid-adolescents have adapted to their living arrangements and that other factors play a more pertinent role for HPA-functioning and subjective health.
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| 6. |
- Thorsson, Petra, 1987-, et al.
(författare)
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Modelling atmospheric icing : A comparison between icing calculated with measured meteorological data and NWP data
- 2015
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Ingår i: Cold Regions Science and Technology. - : Elsevier. - 0165-232X .- 1872-7441. ; 119, s. 124-131
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Tidskriftsartikel (refereegranskat)abstract
- In this case study several periods of measured active icing events have been compared with calculated activeicing. Icing events from three winter seasons in Sweden have been selected as a base for studying how well acommonly used method to calculate icing can capture icing events, aswell as to try out a newapproach. Anotherpurpose is to enlighten parties interested in atmospheric icing of the challenges of calculating icing. For thosewith little knowledge of Numerical Weather Prediction (NWP) models it can be hard to understand why thereare differences between two models, or even the same model using different physical parameterisation schemes.In this study data fromtwoNWP models have been used to calculate icing, aswell as being compared with a newapproach using meteorological measurements to calculate icing. Using meteorological measurements to calculateicing is an interesting alternative as it is computationally less expensive than using aNWP model to generatethe necessary data.All tested methods could at times capture the dynamics of the measured icing, though there are on occasion largedifferences between the different calculated icing and also between calculations and measurements. This highlightsthe importance of having an understanding of NWP models when studying atmospheric icing; there canbe a large spread between different models, and also when using the same model with different schemes. Theresults show that calculated icing is comparable to measured icing and that the methodologies investigatedare viable options for calculating atmospheric icing.
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