| 1. |
- Andersson, Elisabet, et al.
(författare)
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GSLG – Ett svenskt bibliotekskonsortium
- 2008
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Ingår i: BBL : Biblioteksbladet. - 0006-1867. ; 93:10, s. 22-24
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Andersson, Elisabet, et al.
(författare)
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GSLG – Ett svenskt bibliotekskonsortium
- 2008
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Ingår i: BBL : Biblioteksbladet. - 0006-1867. ; 93:10, s. 22-24
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- 1997 bildade fem högskolebibliotek ett ”konsortium” – ett samarbete kring ett gemensamt bibliotekssystem. Styrelsen för Guiding Star Library Group, gslg, summerar ett tioårigt projekt som har haft stor betydelse för samtliga inblandade parter och i hög grad bidragit till att öka kunskapen och kompetensen hos de medverkande.
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| 3. |
- André, Benny, et al.
(författare)
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Friction and contact resistance of nanocomposite Ti-Ni-C coatings
- 2011
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Ingår i: Wear. - : Elsevier BV. - 0043-1648 .- 1873-2577. ; 270:9-10, s. 555-566
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Tidskriftsartikel (refereegranskat)abstract
- Ceramic nanocomposite coatings in the Ti-Ni-C were deposited using PVD and studied with respect to tribological properties and contact resistance. It was shown that coatings could be deposited combining of a low contact resistance and a low friction coefficient against silver, making them suitable for use in high performance electrical contacts.Nine coatings with different amounts of C and Ni were deposited. Coatings on flat Ni plated copper substrates were tested in a tribological ball-on-disc setup against ball bearing steel balls. Depending on primarily the amount of carbon the coatings showed very different friction coefficient and wear rate. The coatings were also deposited on cylindrical Ni plated copper substrates. Using geometrically identical silver plated cylinders as counter surface these were evaluated in a test setup better resembling a real life electrical contact. For most coatings a low electrical contact resistance was measured. The evolution of friction coefficient and contact resistance was correlated to wear marks and contact tracks, with their generated tribofilms, as examined after testing using electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy.
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| 4. |
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| 5. |
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| 6. |
- Brandt, Backa Fredrik, 1972-
(författare)
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Botniabanan - förväntningar i tid och rum på regional utveckling och resande
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the thesis is twofold: to analyze the effects of the expectations on the Bothnia Line on the housing market and expectations on railway use. To fulfill these aims, three questions are considered:1. To what extent is property prices influenced by the expected effects of the Bothnia Line?2. Are there differences in expectations on regional development and future journeys between residents in different locations and with different individual characteristics?3. How are trips to work affected by the expectations on the Bothnia Line and the performance of the train service according to residents in different locations?Property prices are investigated quantitatively with data delivered from Lantmäteriet. The data contains every sold property from 1994 to 2001 in the municipalities of Umeå, Nordmaling, and Örnsköldsvik. Expectations on regional development and future traveling on the Bothnia Line were investigated with two questionnaires conducted in the autumn of 2002.The empirical results from the study of property prices are clear. There are no signs of influence from the Bothnia Line on the property prices close to the railway stations or in the proximity of the railway.The empirical results from the questionnaires reveal a mixed picture of the expectations. In the municipalities located furthest away from the railway, the expectations are low. On the contrary, a large proportion (>75 %) of the residents in municipalities along the railway line believe it can be useful for the population in general when searching for new employment opportunities. This is especially true for males living in Örnsköldsvik. A significantly smaller proportion (≈25 %) believes they will use the railway themselves.One explanation to the geographic variations is that they are a result from an ongoing diffusion process. Residents in Örnsköldsvik were the first ones to have a visual image of the railway since the construction started there. As the construction continues, the expectations might increase in other locations as well. Another possibility is that people only react on word of mouth from someone that actually made a trip before they consider changing the mode of transport. If that is the case, the expectations will increase only after the opening of the railway line.With the exception of residents in Nordmaling, expectations on future journeys with the Bothnia Line are low. The low expectations on journeys on the Bothnia Line might be explained by the lack of attraction between the places along the line. They are satisfied with their present situation and cannot find any rationale to consider other alternatives. It is a different story if they are forced to consider other alternatives. The result from a stated preference study shows that if they are offered employment at another place, the majority is willing to commute.
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| 7. |
- Chen, Jingjing, et al.
(författare)
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A high efficient heat exchanger with twisted geometries for biogas process with manure slurry
- 2020
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 279
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Tidskriftsartikel (refereegranskat)abstract
- Heat-transfer enhancement in manure slurry is crucial for increasing the efficiency and production of biogas during anaerobic digestion in biogas plants. In this study, a novel heat exchanger with an optimal twisted geometry was developed based on the numerical screening of the twisted tubes with equilateral polygons, and experiments were conducted to validate the numerical results. It was observed that the SST k-ω model is more efficient than other turbulence models in representing the heat transfer performance of the twisted tubes, and the numerical model with a thermostatic wall can be used to reliably screen the twisted geometries. The twisted hexagonal tube has the optimal geometry, with enhancement capability of up to 1.4 times compared to that of the circular tube. The formation of high continuity regions with relatively strong heat-transfer rates along the heat-exchange wall is the main reason for the high performance during heat transfer. The external heating process was integrated in a full-scale biogas plant, and the model and algorithm were developed and validated with additional experiments to describe the overall performance of both conventional and screened optimal geometries under different conditions. It was observed that a profit equivalent to 39% of total production for a large-scale biogas plant can be achieved owing to energy conservation in external heating with the twisted hexagonal tubes.
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| 8. |
- Chen, Jingjing, et al.
(författare)
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Heat-transfer performance of twisted tubes for highly viscous food waste slurry from biogas plants
- 2022
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Ingår i: Biotechnology for Biofuels and Bioproducts. - : Springer Nature. - 2731-3654. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- Background: The use of food waste as feedstock shows high production of biogas via anaerobic digestion, but requires efficient heat transfer in food waste slurry at heating and cooling processes. The lack of rheological properties hampered the research on the heat-transfer process for food waste slurry. Referentially, the twisted hexagonal and elliptical rubes have been proved as the optimal enhanced geometry for heat transfer of medium viscous slurries with non-Newtonian behavior and Newtonian fluids, respectively. It remains unknown whether improvements can be achieved by using twisted geometries in combination with food waste slurry in processes including heating and cooling.Results: Food waste slurry was observed to exhibit highly viscous, significant temperature-dependence, and strongly shear-thinning rheological characteristics. Experiments confirmed the heat-transfer enhancement of twisted hexagonal tubes for food waste slurry and validated the computational fluid dynamics-based simulations with an average deviation of 14.2%. Twisted hexagonal tubes were observed to be more effective at low-temperature differences and possess an enhancement factor of up to 2.75; while twisted elliptical tubes only exhibited limited heat-transfer enhancement at high Reynolds numbers. The heat-transfer enhancement achieved by twisted hexagonal tubes was attributed to the low dynamic viscosity in the boundary layer induced by the strong and continuous shear effect near the walls of the tube.Conclusions: This study determined the rheological properties of food waste slurry, confirmed the heat-transfer enhancement of the twisted hexagonal tubes experimentally and numerically, and revealed the mechanism of heat-transfer enhancement based on shear rate distributions.
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| 10. |
- Eriksson, Marie, et al.
(författare)
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Large improvements in major cardiovascular risk factors in the population of northern Sweden : the MONICA study 1986–2009
- 2011
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 269:2, s. 219-231
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. The incidence of cardiovascular disease has declined rapidly in Sweden since the 1980s. We explored changes in major cardiovascular risk factors in northern Sweden between 1986 and 2009.Design. Since 1986, six population surveys have been carried out in northern Sweden using procedures of the World Health Organization MONICA project. The population age range was 25–64 years in 1986 and 1990, and 25–74 years from 1994. Trends were analysed using generalized linear models.Results. A total of 10 586 subjects were included in the surveys. Blood pressure decreased by 4.9/3.9 mmHg in women and 1.8/1.5 mmHg in men aged 25–64 years between 1986 and 2009. In men and women aged 65–74 years, the decrease was 12.6/6.1 mmHg between 1994 and 2009. From 1994, the use of blood pressure‐lowering drugs increased, particularly among the older subgroup. The prevalence of smoking halved between 1986 and 2009; 11% of women and 9% of men were smokers in 2009. Cholesterol levels decreased by 0.9 mmol L−1 in the younger age group (25–64 years), and the use of lipid‐lowering agents increased from 1994. Among subjects aged 25–64 years, one in five was obese in 2009, which was twice as many as in 1986, and body mass index (BMI) increased by 1.5 kg m−2, corresponding to an increase in weight of 4 kg. There was no further increase in BMI from 2004. The prevalence of diabetes did not change between 1986 and 2009. The proportion that received a university education increased markedly in all age groups, especially in women, during the study period.Conclusions. Significant improvements were observed in major cardiovascular risk factors in northern Sweden between 1986 and 2009.
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