| 1. |
- Bolmsvik, Åsa, 1975-
(författare)
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Structural-acoustic vibrations in wooden assemblies : Experimental modal analysis and finite element modelling
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This doctoral thesis concerns flanking transmission in light weight, wooden multi-storey buildings within the low frequency, primarily 20-120 Hz. The overall aim is to investigate how the finite element method can contribute in the design phase to evaluate different junctions regarding flanking transmission.Two field measurements of accelerations in light weight wooden buildings have been evaluated. In these, two sources; a stepping machine, and an electrodynamic shaker, were used. The shaker was shown to give more detailed information. However, since a light weight structure in field exhibit energy losses to surrounding building parts, reliable damping estimates were difficult to obtain.In addition, two laboratory measurements were made. These were evaluated using experimental modal analysis, giving the eigenmodes and the damping of the structures. The damping for these particular structures varies significantly with frequency, especially when an elastomer is used in the floor-wall junction. The overall damping is also higher when elastomers are used in the floor-wall junction in comparison to a screwed junction. By analysing the eigenmodes, using the modal assurance criterion, of the same structure with two types of junctions it was concluded that the modes become significantly different. Thereby the overall behavior differs.Several finite element models representing both the field and laboratory test setups have been made. The junctions between the building blocks in the models have been modeled using tie or springs and dashpots. Visual observation and the modal assurance criterion show that there is more rotational stiffness in the test structures than in the models.The findings in this doctoral thesis add understanding to how modern joints in wooden constructions can be represented by FE modelling. They will contribute in developing FE models that can be used to see the acoustic effects prior to building an entire house. However, further research is still needed.
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| 2. |
- Stenberg, Erik, 1979-, et al.
(författare)
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Closure of mesenteric defects in laparoscopic gastric bypass : a multicentre, randomised, parallel, open-label trial
- 2016
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Ingår i: The Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 387:10026, s. 1397-1404
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Tidskriftsartikel (refereegranskat)abstract
- Background: Small bowel obstruction due to internal hernia is a common and potentially serious complication after laparoscopic gastric bypass surgery. Whether closure of surgically created mesenteric defects might reduce the incidence is unknown, so we did a large randomised trial to investigate.Method: This study was a multicentre, randomised trial with a two-arm, parallel design done at 12 centres for bariatric surgery in Sweden. Patients planned for laparoscopic gastric bypass surgery at any of the participating centres were off ered inclusion. During the operation, a concealed envelope was opened and the patient was randomly assigned to either closure of mesenteric defects beneath the jejunojejunostomy and at Petersen's space or non-closure. After surgery, assignment was open label. The main outcomes were reoperation for small bowel obstruction and severe postoperative complications. Outcome data and safety were analysed in the intention-to-treat population. This trial is registered with ClinicalTrials. gov, number NCT01137201.Findings: Between May 1, 2010, and Nov 14, 2011, 2507 patients were recruited to the study and randomly assigned to closure of the mesenteric defects (n= 1259) or non-closure (n= 1248). 2503 (99.8%) patients had follow-up for severe postoperative complications at day 30 and 2482 (99.0%) patients had follow-up for reoperation due to small bowel obstruction at 25 months. At 3 years after surgery, the cumulative incidence of reoperation because of small bowel obstruction was signifi cantly reduced in the closure group (cumulative probability 0.055 for closure vs 0.102 for non-closure, hazard ratio 0.56, 95% CI 0.41-0.76, p= 0.0002). Closure of mesenteric defects increased the risk for severe postoperative complications (54 [4.3%] for closure vs 35 [2.8%] for non-closure, odds ratio 1.55, 95% CI 1.01-2.39, p= 0.044), mainly because of kinking of the jejunojejunostomy.Interpretation: The results of our study support the routine closure of the mesenteric defects in laparoscopic gastric bypass surgery. However, closure of the mesenteric defects might be associated with increased risk of early small bowel obstruction caused by kinking of the jejunojejunostomy.
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| 3. |
- Aidas, Kestutis, et al.
(författare)
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The Dalton quantum chemistry program system
- 2014
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Ingår i: WIREs Computational Molecular Science. - : Wiley. - 1759-0876 .- 1759-0884. ; 4:3, s. 269-284
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Tidskriftsartikel (refereegranskat)abstract
- Dalton is a powerful general-purpose program system for the study of molecular electronic structure at the Hartree-Fock, Kohn-Sham, multiconfigurational self-consistent-field, MOller-Plesset, configuration-interaction, and coupled-cluster levels of theory. Apart from the total energy, a wide variety of molecular properties may be calculated using these electronic-structure models. Molecular gradients and Hessians are available for geometry optimizations, molecular dynamics, and vibrational studies, whereas magnetic resonance and optical activity can be studied in a gauge-origin-invariant manner. Frequency-dependent molecular properties can be calculated using linear, quadratic, and cubic response theory. A large number of singlet and triplet perturbation operators are available for the study of one-, two-, and three-photon processes. Environmental effects may be included using various dielectric-medium and quantum-mechanics/molecular-mechanics models. Large molecules may be studied using linear-scaling and massively parallel algorithms. Dalton is distributed at no cost from for a number of UNIX platforms.
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| 4. |
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| 5. |
- Boberg, Elin, 1980-, et al.
(författare)
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Pollinator shifts and the evolution of spur length in the moth-pollinated orchid Platanthera bifolia
- 2014
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Ingår i: Annals of Botany. - : Oxford University Press (OUP). - 0305-7364 .- 1095-8290. ; 113:2, s. 267-275
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Tidskriftsartikel (refereegranskat)abstract
- Plantpollinator interactions are thought to have shaped much of floral evolution. Yet the relative importance of pollinator shifts and coevolutionary interactions for among-population variation in floral traits in animal-pollinated species is poorly known. This study examined the adaptive significance of spur length in the moth-pollinated orchid Platanthera bifolia. Geographical variation in the length of the floral spur of P. bifolia was documented in relation to variation in the pollinator fauna across Scandinavia, and a reciprocal translocation experiment was conducted in south-east Sweden between a long-spurred woodland population and a short-spurred grassland population. Spur length and pollinator fauna varied among regions and habitats, and spur length was positively correlated with the proboscis length of local pollinators. In the reciprocal translocation experiment, long-spurred woodland plants had higher pollination success than short-spurred grassland plants at the woodland site, while no significant difference was observed at the grassland site. The results are consistent with the hypothesis that optimal floral phenotype varies with the morphology of the local pollinators, and that the evolution of spur length in P. bifolia has been largely driven by pollinator shifts.
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| 6. |
- Chen, Qing, et al.
(författare)
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On Negative Diagonal Elements in the Diffusion Coefficient Matrix of Multicomponent Systems
- 2018
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Ingår i: JOURNAL OF PHASE EQUILIBRIA AND DIFFUSION. - : Springer. - 1547-7037 .- 1863-7345. ; 39:5, s. 592-596
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Tidskriftsartikel (refereegranskat)abstract
- In multicomponent systems the diffusion coefficient turns into a matrix. The diagonal elements represent diffusion of a species caused by its own concentration gradient. In a thermodynamically stable binary alloy it is easy to see that this diagonal element must be positive but in a multicomponent system it is less obvious. The sign of the diagonal elements in the general case is discussed in this report. It is shown that the sign of an individual diagonal element has no physical meaning but can be changed by changing the dependent concentration variable. Only the sum of all the diagonal elements need to be positive in a stable system.
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| 7. |
- Ecke, Frauke, et al.
(författare)
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Sublethal Lead Exposure Alters Movement Behavior in Free-Ranging Golden Eagles
- 2017
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 51:10, s. 5729-5736
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Tidskriftsartikel (refereegranskat)abstract
- Lead poisoning of animals due to ingestion of fragments from lead-based ammunition in carcasses and offal of shot wildlife is acknowledged globally and raises great concerns about potential behavioral effects leading to increased mortality risks. Lead levels in blood were correlated with progress of the moose hunting season. Based on analyses of tracking data, we found that even sublethal lead concentrations in blood (25 ppb, wet weight), can likely negatively affect movement behavior (flight height and movement rate) of free ranging scavenging Golden Eagles (Aquila chrysaetos). Lead levels in liver of recovered post-mortem analyzed eagles suggested that sublethal exposure increases the risk of mortality in eagles. Such adverse effects on animals are probably common worldwide and across species, where game hunting with lead-based ammunition is widespread. Our study highlights lead exposure as a considerably more serious threat to wildlife conservation than previously realized and suggests implementation of bans of lead ammunition for hunting.
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| 8. |
- Engfeldt, Andreas, et al.
(författare)
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RG 2000 – the New Gravity Reference Frame of Sweden
- 2019
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Ingår i: Geophysica. - : Geophysical Society of Finland. - 0367-4231 .- 2324-0741. ; 54:1, s. 69-92
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Tidskriftsartikel (refereegranskat)abstract
- The increased need for improved geoid models for Global Navigation Satellite Systems (GNSS) height determination calls for additional gravity observations and quality assurance of existing data. In this perspective, a modern gravity system and the renovation of an already existing high order gravity network is considered as a moderate strategic investment which provides a firm foundation for further activities. Here the new gravity reference frame RG 2000 for Sweden is presented. RG 2000 is realized by absolute gravity observations at 109 stations. The absolute points are connected via old and new relative gravity observations, including another 216 points. Points and observations have been chosen so that good overlap with the older Swedish reference frames, RG 62 and RG 82, is achieved, allowing to evaluate the older frames and transformations between them. RG 2000 is based on a zero permanent tide system with epoch 2000.
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| 9. |
- Eriksson, Olle, 1954-, et al.
(författare)
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Women with Premenstrual Dysphoria Lack the Seemingly Normal Premenstrual Right-Sided Relative Dominance of 5-HTP-Derived Serotonergic Activity in the Dorsolateral Prefrontal Cortices - A Possible Cause of Disabling Mood Symptoms.
- 2016
-
Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 11:9
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Tidskriftsartikel (refereegranskat)abstract
- To investigate potential quantitative and qualitative differences in brain serotonergic activity between women with Premenstrual Dysphoria (PMD) and asymptomatic controls.Serotonin-augmenting drugs alleviate premenstrual mood symptoms in the majority of women with PMD while serotonin-depleting diets worsen PMD symptoms, both indicating intrinsic differences in brain serotonergic activity in women with PMD compared to asymptomatic women.Positron-emission tomography with the immediate precursor of serotonin, 5-hydroxytryptophan (5-HTP), radiolabelled by 11C in the beta-3 position, was performed in the follicular and luteal phases for 12 women with PMD and 8 control women. Brain radioactivity-a proxy for serotonin precursor uptake and synthesis-was measured in 9 regions of interest (ROIs): the right and left sides of the medial prefrontal cortex, dorsolateral prefrontal cortex, putamen and caudate nucleus, and the single "whole brain".There were no significant quantitative differences in brain 5-HTP-derived activity between the groups in either of the menstrual phases for any of the 9 ROIs. However, multivariate analysis revealed a significant quantitative and qualitative difference between the groups. Asymptomatic control women showed a premenstrual right sided relative increase in dorsolateral prefrontal cortex 5-HTP derived activity, whereas PMD women displayed the opposite (p = 0.0001). Menstrual phase changes in this asymmetry (premenstrual-follicular) correlated with changes in self ratings of 'irritability' for the entire group (rs = -0.595, p = 0.006). The PMD group showed a strong inverse correlation between phase changes (premenstrual-follicular) in plasma levels of estradiol and phase changes in the laterality (dx/sin) of radiotracer activity in the dorsolateral prefrontal ROI (rs = -0.635; 0.027). The control group showed no such correlation.Absence of increased premenstrual right-sided relative 5-HTP-derived activity of the dorsolateral prefrontal cortices was found to strongly correlate to premenstrual irritability. A causal relationship here seems plausible, and the findings give further support to an underlying frontal brain disturbance in hormonally influenced serotonergic activity in women with PMD. Because of the small number of subjects in the study, these results should be considered preliminary, requiring verification in larger studies.
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| 10. |
- Florén, Anders, et al.
(författare)
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Historiska undersökningar : Grunder i historisk teori, metod och framställnigssätt
- 2018. - 3
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Historiska undersökningar handlar om hur man skriver historia,hur händelser i det förflutna ordnas till ett gripbart sammanhang.Den historiska undersökningen är inte vilken text som helst, den syftar till att besvara en fråga. Men hur ska en sådan fråga formuleras? Och hur ska den försvaras?Författarna resonerar här om hur en historievetenskaplig argumentation ser ut, vilka krav som ställs på framställningssättet,hur man använder metoder och källor, samt vad man ska tänka på då man kritiserar ett vetenskapligt arbete. I boken finns också en användbar begreppsguide där aktuella historieteoretiska begrepp och termer beskrivs.Denna tredje upplaga är grundligt reviderad och aktualiserad.Boken vänder sig främst till studenter på grundläggande nivå i historia, som för första gången ställs inför uppgiften att självständigt göra en historisk undersökning.
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| 11. |
- Goude, Anders
(författare)
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Fluid Mechanics of Vertical Axis Turbines : Simulations and Model Development
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Two computationally fast fluid mechanical models for vertical axis turbines are the streamtube and the vortex model. The streamtube model is the fastest, allowing three-dimensional modeling of the turbine, but lacks a proper time-dependent description of the flow through the turbine. The vortex model used is two-dimensional, but gives a more complete time-dependent description of the flow. Effects of a velocity profile and the inclusion of struts have been investigated with the streamtube model. Simulations with an inhomogeneous velocity profile predict that the power coefficient of a vertical axis turbine is relatively insensitive to the velocity profile. For the struts, structural mechanic loads have been computed and the calculations show that if turbines are designed for high flow velocities, additional struts are required, reducing the efficiency for lower flow velocities.Turbines in channels and turbine arrays have been studied with the vortex model. The channel study shows that smaller channels give higher power coefficients and convergence is obtained in fewer time steps. Simulations on a turbine array were performed on five turbines in a row and in a zigzag configuration, where better performance is predicted for the row configuration. The row configuration was extended to ten turbines and it has been shown that the turbine spacing needs to be increased if the misalignment in flow direction is large.A control system for the turbine with only the rotational velocity as input has been studied using the vortex model coupled with an electrical model. According to simulations, this system can obtain power coefficients close to the theoretical peak values. This control system study has been extended to a turbine farm. Individual control of each turbine has been compared to a less costly control system where all turbines are connected to a mutual DC bus through passive rectifiers. The individual control performs best for aerodynamically independent turbines, but for aerodynamically coupled turbines, the results show that a mutual DC bus can be a viable option.Finally, an implementation of the fast multipole method has been made on a graphics processing unit (GPU) and the performance gain from this platform is demonstrated.
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| 12. |
- Goude, Anders, et al.
(författare)
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Numerical Simulation of a Farm of Vertical Axis Marine Current Turbines
- 2010
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Ingår i: PROCEEDINGS OF THE ASME 29TH INTERNATIONAL CONFERENCE ON OCEAN, OFFSHORE AND ARCTIC ENGINEERING 2010, VOL 3. - 9780791849118 ; , s. 335-344
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Konferensbidrag (refereegranskat)abstract
- For commercial applications of marine current turbines, it can be useful to build several turbines close to each other in a farm, similar to wind turbine parks. To create a good farm configuration, the turbines' mutual interaction needs to be studied. Here, to obtain detailed information, several turbines were simulated together using a 2D vortex method. To limit the computational cost, the vortex method was combined with known profile section data for the blades.First, a single turbine was compared against two turbines in close proximity. The two turbines were tested both with equal and opposite rotational direction, and the two blade pitch angles 0 and 3 degrees were tested. For both a single turbine and the two turbine case, a 3 degree pitch angle gave higher power coefficients than 0 degrees. The differences between 3 and 0 degrees were more significant for the single turbine. In all cases, the two turbine system had higher power coefficient per turbine than the single turbine.A five turbine park was simulated with three different combinations, one with all turbines on a row, and two with a zigzag pattern, where the difference was that the last simulation had larger turbines than the other two. For 0 degrees incident flow angle, the turbines on the row obtained the highest power coefficient, while the larger turbines in zigzag pattern obtained higher total power. The case with the turbines on the row was most insensitive to changes in flow direction, and for a 30 degree change, the row produced the highest total power as well. By locating the turbines inside a channel, all turbines obtained higher power coefficients, and the increase was largest for the large turbines, which blocked the channel to a larger extent.
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| 13. |
- Goude, Anders, et al.
(författare)
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Simulations of a vertical axis turbine in a channel
- 2014
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Ingår i: Renewable energy. - : Elsevier. - 0960-1481 .- 1879-0682. ; 63, s. 477-485
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Tidskriftsartikel (refereegranskat)abstract
- The power coefficient of a turbine increases according to the predictions from streamtube theory for sites with a confined fluid flow. Here, a vertical axis turbine (optimized for free flow) has been simulated by a two-dimensional vortex method, both in a channel and in free flow. The first part of the study concerns the numerical parameters of channel simulations. It is found that for free flow and wide channels, a large number of revolutions is required for convergence (around 100 at the optimal tip speed ratio and increasing with higher tip speed ratio), while for smaller channels, the required number of revolutions decreases. The second part analyses changes in turbine performance by the channel boundaries. The turbine performance increases when the channel width is decreased, although the results are below the predictions from streamtube theory, and this difference increases with decreasing channel width. It is also observed that the optimal tip speed ratio increases with decreasing channel width. By increasing the chord, which decreases the optimal tip speed ratio, the power coefficient can be increased somewhat.
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| 14. |
- Grane, Camilla, et al.
(författare)
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Project: EFESOS - Environmental Friendly efficient Enjoyable and Safety Optimized Systems
- 2012
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Annan publikation (populärvet., debatt m.m.)abstract
- EFESOS is a Swedish Vehicle HMI (Human Machine Interaction) FFI research project. The overall ambition is to make driving of future cars more environmental friendly, enjoyable and safer by means of optimized systems. The project is managed by Volvo Car Corporation (VCC) and it is a collaboration between VCC and seven other research partners including Luleå University of Technology.
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| 15. |
- Hagnestål, Anders, et al.
(författare)
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A Compact Non-Planar Coil Design for the SFLM Hybrid
- 2012
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Ingår i: Journal of fusion energy. - : Springer Science and Business Media LLC. - 0164-0313 .- 1572-9591. ; 31:4, s. 379-388
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Tidskriftsartikel (refereegranskat)abstract
- A non-planar single layer semiconductor coil set for a version of the Straight Field Line Mirror Hybrid concept with reduced magnetic field has been computed. The coil set consists of 30 coils that are somewhat similar to baseball coils with skewed sides. The coil set has been modeled with filamentary current distributions and basic scaling assumptions have been made regarding the coil widths. This coil set is expected to be considerably cheaper than a previous computed coil set. The coils can probably be produced with technologies known today.
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| 16. |
- Hagnestål, Anders, et al.
(författare)
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A study on field and coil designing for a quadrupolar mirror hybrid reactor
- 2011
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Ingår i: Journal of fusion energy. - : Springer Science and Business Media LLC. - 0164-0313 .- 1572-9591. ; 30:2, s. 144-156
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Tidskriftsartikel (refereegranskat)abstract
- A vacuum magnetic field from a superconducting coil set for a single cell minimum B fusion-fission mirror machine reactor is computed. The magnetic field is first optimized for MHD flute stability, ellipticity and field smoothness in a long-thin approximation. Recirculation regions and magnetic expanders are added to the mirror machine without an optimizing procedure. The optimized field is thereafter reproduced by a set of circular and quadrupolar coils. The coils are modelled using filamentary line current distributions. Basic scaling assumptions are implemented for the coil design, with a maximum allowed current density of 1.5 kA/cm2. The coils are optimized using a local optimization method and the resulting field is checked for MHD flute stability and maximum ellipticity.
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| 17. |
- Hagnestål, Anders, 1976-
(författare)
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Coil Design and Related Studies for the Fusion-Fission Reactor Concept SFLM Hybrid
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A fusion-fission (hybrid) reactor is a combination of a fusion device and a subcritical fission reactor, where the fusion device acts as a neutron source and the power is mainly produced in the fission core. Hybrid reactors may be suitable for transmutation of transuranic isotopes in the spent nuclear fuel, due to the safety margin on criticality imposed by the subcritical fission core. The SFLM Hybrid project is a theoretical project that aims to point out the possibilities with steady-state mirror-based hybrid reactors. The quadrupolar magnetic mirror vacuum field is based on the Straight Field Line Mirror field and the central cell is 25 m long. A fission mantle surrounds the mirror cell. The fission to fusion power ratio is about 150 with keff = 0.97, implying that almost all the produced energy comes from fission. Beyond each mirror end magnetic expanders are located, which increase the plasma receiving “divertor” area and provide tolerable heat load on wall materials. The plasma is heated with ion cyclotron radio frequency heating and the fission mantle is cooled using a liquid lead-bismuth eutectic. The device is self-sufficient in tritium, and does not seem to suffer from severe material problems. A remaining issue may be the plasma electron temperature, which need to reach about 500 eV for efficient power production. In this doctoral thesis, theoretical work has been done with the magnetic coil system of such a device and also with the overall concept. A new coil type, the fishbone coil, suitable for single cell quadrupolar mirrors, has been invented. Two vacuum field coil sets with satisfying properties have been found, where the most recent coil set consists of fishbone coils. Finite ß effects on the magnetic field have been investigated, showing that the flux tube ellipticity increases with ß. The ellipticity of the vacuum field increases slightly with radius, but with finite ß it decreases with radius. The maximum flux surface radial extensions decrease with ß, which is an unexpected and beneficial result. A radial invariant has also been identified, and particle simulations have been made to emphasize that quadrupolar mirrors must be symmetric or confinement may be lost.
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| 18. |
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| 19. |
- Hagnestål, Anders, et al.
(författare)
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Coil System For a Mirror-Based Hybrid Reactor
- 2012
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Ingår i: Fusion for Neutrons and Subcritical Nuclear Fission. - : AIP. - 9780735410381 ; , s. 217-223
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Konferensbidrag (refereegranskat)abstract
- Two different superconducting coil systems for the SFLM Hybrid study - a quadrupolar mirror based fusion-fission reactor study - are presented. One coil system is for a magnetic field with 2 T at the midplane and a mirror ratio of four. This coil set consists of semi-planar coils in two layers. The alternative coil system is for a downscaled magnetic field of 1.25 T at the midplane and a mirror ratio of four, where a higher beta is required to achieve sufficient the neutron production. This coil set has one layer of twisted 3D coils. The 3D coils are expected to be considerably cheaper than the semiplanar, since NbTi superconductors can be used for most coils instead of Nb3Sn due to the lower magnetic field.
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| 20. |
- Hagnestål, Anders, et al.
(författare)
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Field and Coil Design for a Quadrupolar Mirror Hybrid Reactor
- 2011
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Ingår i: Journal of fusion energy. - : Springer Science and Business Media LLC. - 0164-0313 .- 1572-9591. ; 30:2, s. 144-156
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Tidskriftsartikel (refereegranskat)abstract
- A vacuum magnetic field from a superconducting coil set for a single cell minimum B fusion-fission mirror machine reactor is computed. The magnetic field is first optimized for MHD flute stability, ellipticity and field smoothness in a long-thin approximation. Recirculation regions and magnetic expanders are added to the mirror machine without an optimizing procedure. The optimized field is thereafter reproduced by a set of circular and quadrupolar coils. The coils are modelled using filamentary line current distributions. Basic scaling assumptions are implemented for the coil design, with a maximum allowed current density of 1.5 kA/cm(2). The coils are optimized using a local optimization method and the resulting field is checked for MHD flute stability and maximum ellipticity.
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| 21. |
- Hagnestål, Anders, et al.
(författare)
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Radial Confinement in Non-Symmetric Quadrupolar Mirrors
- 2013
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Ingår i: Journal of fusion energy. - : Springer. - 0164-0313 .- 1572-9591. ; 32:3, s. 327-335
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Tidskriftsartikel (refereegranskat)abstract
- Charged particles in symmetric quadrupolar mirrors are radially confined and have an associated radial invariant. In a symmetric quadrupolar field the magnetic field modulus satisfies B(z)=−B(z) along the axis if z = 0 defines the field minimum of the mirror, and the quadrupolar field has a corresponding symmetry. The field in the anchor cells of a tandem mirror need not obey a corresponding symmetry. In this paper, the radial confinement of non-symmetric mirrors is examined by tracing sample ions in the magnetic field. It is found that for non-symmetric mirrors, particles are typically not confined, and no radial invariant exists for such devices. Without attention to this effect in the field and coil design, radial confinement of trapped particles may be lost.
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| 22. |
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| 23. |
- Hagnestål, Anders, et al.
(författare)
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Theoretical field and coil design for a single cell minimum-B mirror hybrid reactor
- 2011
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Ingår i: Fusion science and technology. - 1536-1055 .- 1943-7641. ; 59:1T, s. 217-219
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Tidskriftsartikel (refereegranskat)abstract
- A vacuum magnetic field from a superconducting coil set for a single cell minimum-B mirror-based,fission-fusion reactor is computed. The magnetic field is optimized for MHD stability, ellipticity and field smoothness. A recirculation region and wide magnetic expanders on both sides are provided to the central mirror cell. A coil set producing this field is computed which consists of circular and quadrupolar coils. Basic scaling assumptions are made for the coil dimensions, based on a maximum allowed current density of 1.5 kA/cm(2) for superconducting coils. Sufficient space is available for a fission mantle. The field produced by the coils is checked for MHD plasma stability and maximum ellipticity. The resulting confinement region is 25 in long with a 40 cm midplane plasma radius.
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| 24. |
- Hagnestål, Anders, et al.
(författare)
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Vacuum Field Ellipticity Dependence on Radius in Quadrupolar Mirror Machines
- 2012
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Ingår i: Journal of fusion energy. - : Springer Netherlands. - 0164-0313 .- 1572-9591. ; 31:5, s. 448-454
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Tidskriftsartikel (refereegranskat)abstract
- The vacuum field flux tube ellipticity dependence on radius for quadrupolar mirror machines has been investigated. A third order expression in the paraxial approximation has been derived for the vacuum field ellipticity. The dependence of ellipticity on midplane radius has been examined in the SFLM Hybrid and the outermost plasma flux tube is 3.5 cm wider than predicted by the first order paraxial approximation, which is within boundaries set by the first wall. The third order approximation has a high accuracy for the ellipticity for long-thin mirrors such as the SFLM Hybrid, and even the first order approximation that is independent of radius is sufficient in many applications. The ellipticity dependence on midplane radius for mirrors with more strongly localized quadrupolar fields than the SFLM Hybrid is also shown to be minor.
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| 25. |
- Israelsson, Johan, et al.
(författare)
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Health status and psychological distress among in-hospital cardiac arrest survivors in relation to gender
- 2017
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Ingår i: Resuscitation. - : Elsevier. - 0300-9572 .- 1873-1570. ; 114, s. 27-33
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To describe health status and psychological distress among in-hospital cardiac arrest (IHCA) survivors in relation to gender.METHODS: This national register study consists of data from follow-up registration of IHCA survivors 3-6 months post cardiac arrest (CA) in Sweden. A questionnaire was sent to the survivors, including measurements of health status (EQ-5D-5L) and psychological distress (HADS).RESULTS: Between 2013 and 2015, 594 IHCA survivors were included in the study. The median values for EQ-5D-5L index and EQ VAS among survivors were 0.78 (q1-q3=0.67-0.86) and 70 (q1-q3=50-80) respectively. The values were significantly lower (p<0.001) in women compared to men. In addition, women reported more problems than men in all dimensions of EQ-5D-5L, except self-care. A majority of the respondents reported no problems with anxiety (85.4%) and/or symptoms of depression (87.0%). Women reported significantly more problems with anxiety (p<0.001) and symptoms of depression (p<0.001) compared to men. Gender was significantly associated with poorer health status and more psychological distress. No interaction effects for gender and age were found.CONCLUSIONS: Although the majority of survivors reported acceptable health status and no psychological distress, a substantial proportion reported severe problems. Women reported worse health status and more psychological distress compared to men. Therefore, a higher proportion of women may be in need of support. Health care professionals should make efforts to identify health problems among survivors and offer individualised support when needed.
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| 26. |
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| 27. |
- Israelsson, Johan, 1970-, et al.
(författare)
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Post cardiac arrest care and follow-up in Sweden – a national survey
- 2016
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Ingår i: BMC Nursing. - : Springer Science and Business Media LLC. - 1472-6955. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundRecent decades have shown major improvements in survival rates after cardiac arrest. However, few interventions have been tested in order to improve the care for survivors and their family members. In many countries, including Sweden, national guidelines for post cardiac arrest care and follow-up programs are not available and current practice has not previously been investigated. The aim of this survey was therefore to describe current post cardiac arrest care and follow-up in Sweden.MethodsAn internet based questionnaire was sent to the resuscitation coordinators at all Swedish emergency hospitals (n = 74) and 59 answers were received. Quantitative data were analysed with descriptive statistics and free text responses were analysed using manifest content analysis.ResultsAlmost half of the hospitals in Sweden (n = 27, 46 %) have local guidelines for post cardiac arrest care and follow-up. However, 39 % of them reported that these guidelines were not always applied. The most common routine is a follow-up visit at a cardiac reception unit. If the need for neurological or psychological support are discovered the routines are not explicit. In addition, family members are not always included in the follow-up.ConclusionsAlthough efforts are already made to improve post cardiac arrest care and follow-up, many hospitals need to focus more on this part of cardiac arrest treatment. In addition, evidence-based national guidelines will have to be developed and implemented in order to achieve a more uniform care and follow-up for survivors and their family members. This national survey highlights this need, and might be helpful in the implementation of such guidelines.
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| 28. |
- Kurbasic, Azra, et al.
(författare)
-
Gene-Lifestyle Interactions in Complex Diseases : Design and Description of the GLACIER and VIKING Studies
- 2014
-
Ingår i: Current nutrition reports. - : Springer Science and Business Media LLC. - 2161-3311. ; 3:4, s. 400-411
-
Tidskriftsartikel (refereegranskat)abstract
- Most complex diseases have well-established genetic and non-genetic risk factors. In some instances, these risk factors are likely to interact, whereby their joint effects convey a level of risk that is either significantly more or less than the sum of these risks. Characterizing these gene-environment interactions may help elucidate the biology of complex diseases, as well as to guide strategies for their targeted prevention. In most cases, the detection of gene-environment interactions will require sample sizes in excess of those needed to detect the marginal effects of the genetic and environmental risk factors. Although many consortia have been formed, comprising multiple diverse cohorts to detect gene-environment interactions, few robust examples of such interactions have been discovered. This may be because combining data across studies, usually through meta-analysis of summary data from the contributing cohorts, is often a statistically inefficient approach for the detection of gene-environment interactions. Ideally, single, very large and well-genotyped prospective cohorts, with validated measures of environmental risk factor and disease outcomes should be used to study interactions. The presence of strong founder effects within those cohorts might further strengthen the capacity to detect novel genetic effects and gene-environment interactions. Access to accurate genealogical data would also aid in studying the diploid nature of the human genome, such as genomic imprinting (parent-of-origin effects). Here we describe two studies from northern Sweden (the GLACIER and VIKING studies) that fulfill these characteristics.
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| 29. |
- Lennström, David, et al.
(författare)
-
Determination of radiated sound power from an electric rear axle drive in-situ and its contribution to interior noise
- 2013
-
Ingår i: SAE technical paper series. - : SAE International. - 0148-7191. ; 6:3, s. 1554-1563
-
Tidskriftsartikel (refereegranskat)abstract
- System and component target setting for noise and vibration are important activities within automotive product development. New challenges arise when electric motors are introduced into cars traditionally powered by combustion engines. The emitted noise from an electric traction motor for hybrid electric vehicles is characterized by high frequency tonal components from the dominating magnetic harmonics which can be perceived as annoying. Sound power is frequently used for quantifying the airborne noise from rotating electrical machines. This paper describes the process of determining the radiated sound power from an automobile electric rear axle drive in-situ and its contribution to interior cabin noise for a prominent rotor order. The sound power was calculated by combining the average stator surface vibration velocity together with an estimate of the radiation efficiency. To model the radiation efficiency, the vibration shape of the cylindrically shaped stator shell was determined by means of operational deflection shapes. The acoustic transfer functions between the source and receiver positions close to a passenger's ear, were defined as the ratio of sound pressure and sound power. By combining the acoustic transfer functions with the calculated operational sound power, the airborne interior noise can be predicted. The calculated interior noise levels were found to be in accordance, within approximately 3 dB, with the measured airborne noise from the stator shell. This indicated that the method is valid and could be helpful for calculating allowed radiated power from interior noise targets and acoustic transfer functions.
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| 30. |
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| 31. |
- Lennström, David, et al.
(författare)
-
The influence of the acoustic transfer functions on the estimated interior noise from an electric rear axle drive
- 2014
-
Ingår i: SAE International Journal of Passenger Cars - Mechanical Systems. - : SAE International. - 1946-3995 .- 1946-4002. ; 7:1, s. 413-422
-
Tidskriftsartikel (refereegranskat)abstract
- In the vehicle development process, targets are defined to fulfill customers' expectations on acoustic comfort. The interior complete vehicle acoustic targets can be cascaded down to system and component targets, e.g. insulation properties and source strengths. The acoustic transfer functions (ATFs) from components radiating airborne noise play a central role for the interior sound pressure levels. For hybrid vehicles fitted with an electric traction motor, the contribution of high frequency tonal components radiated from the motor housing needs to be controlled. The interior sound pressure due to an airborne motor order can be estimated by surface velocities and ATFs. This study addresses the ATFs measured from a large number of positions located around an electric rear axle drive (ERAD) and their influence on estimated interior noise. First, the magnitude variation between the individual ATFs and how it clearly can be visualized was presented. Displaying all ATFs in a color map revealed the magnitude at each geometrical location of the respective microphone. Secondly, the influence of the ATF's spatial resolution on estimated interior sound pressure was investigated. This was done for theoretical models of the stator shell source shape and also for measured surface velocities. By reducing the spatial resolution from 0.05 to 0.10 m between each microphone, the difference in noise contribution is typically within three decibels with a 12th octave smoothing filter applied to the narrow-band data. The findings from this work provide insight in the risks of compromising with the number of ATF's needed for contribution analysis.
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| 32. |
- Ljunggren, Fredrik, et al.
(författare)
-
Elastic layers to reduce sound transmission in lightweight buildings
- 2013
-
Ingår i: Building Acoustics. - 1351-010X. ; 20:1, s. 25-42
-
Tidskriftsartikel (refereegranskat)abstract
- To obtain satisfactory sound insulation is a challenging task when designing lightweight buildings. Poor performance at low frequencies as well as severe flanking transmission has traditionally often been more pronounced compared to heavier constructions. In the present casestudy based paper, various aspects of using elastic layers to improve sound insulation in lightweight buildings are considered.The effect on impact and airborne sound insulation by using two different kinds of vibration insulators between floor plans was examined together with the effect of using glues of various degree of elasticity in the construction. In situ measurements were performed inside a four-storey wooden frame based residential building and statistically significant variations in sound insulation were found.The efficiency of the two vibration insulators was further evaluated by vibration reduction measurements over the junctions. The difference in vibration reduction was found to be nearly constant in the frequency range 50-1000 Hz while the improvement of impact sound insulation increased by frequency.Along term test of elastic glues was also conducted, during three years, for stability over time. The best glues preserved a significantly higher damping ratio over time compared to the main part of the glues.
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| 33. |
- Ljunggren, Fredrik, et al.
(författare)
-
How to match building acoustic measurements with subjective judgments
- 2012
-
Ingår i: Inter-Noise 2012. - 9781627485609 ; , s. 8922-8996
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Swedish research program AkuLite deals with various aspects regarding sound and vibration within lightweight buildings. As the popularity of lightweight block of flats increases it has been noticed that standardised (ISO) measurements, like airborne and impact sound insulation, tend to show different correlation with subjective experiences compared with concrete buildings. It is therefore of importance to either develop existing evaluation methods or to find new measurement parameters for better correspondence. In the project, series of sound and vibration measurements are carried out in various types of buildings. The measurements include extended frequency range and various sources as well as increased number of extracted parameters compared to existing standards. In parallel, questionnaires are distributed to the tenants, in the same buildings, where they give answer to questions regarding the experienced sound annoyance in their flat. Statistical analysis of the correlation between the objective measurement parameters and the subjective opinions from the tenants will be carried out.
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| 34. |
- Ljunggren, Fredrik, et al.
(författare)
-
Potential solutions to improved sound performance of volume based lightweight multi-storey timber buildings
- 2011
-
Ingår i: Applied Acoustics. - : Elsevier BV. - 0003-682X .- 1872-910X. ; 72:4, s. 231-240
-
Tidskriftsartikel (refereegranskat)abstract
- Lightweight building systems in general suffer from poor sound insulation, especially in the low frequency region. Since no reliable mathematical models that can predict the impact sound pressure level exists, the lightweight building design is to a high extent based upon previous experience and upon measurements. A special difficulty is related to experimental measurements since the variation among identical units must not be neglected. A modern volume based lightweight wooden buildingn concept has here been tested by numerous well controlled measurements, in laboratory as well as in more field like conditions. The volume construction technique offers new possibilities and challenges to improve sound insulation in light weight timber construction. The main purpose was to investigate how different constructional solutions in the floor, like plaster board, mineral wool, elastic glue, dividing board, floating floor etc., affect the sound insulation. Many of the tested modifications resulted in only marginally changed impact sound pressure level but parameters that substantially can improve the sound insulation were found in using elastic glue to mount the floor boards, to install extra board layers and to use floating floors.
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| 35. |
- Mason, Paul, et al.
(författare)
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Simulation of diffusion in surface and interface reactions
- 2010
-
Ingår i: ASM Handbook, vol 22B. - : ASM International. ; , s. 586-599
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Historically, the field of materials science and engineering has focused on establishing the processing-structure- property relationships of materials through experimental trial and error with an understanding of the influence of microstructure—the microstructure, processing, and chemistry all being directly related to the crystallography, kinetics, and thermodynamics of the materials. In comparatively recent years, as computational methods have evolved, it has been possible to predict some such properties and relationships through numerical simulation.
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| 36. |
- Moiseenko, V. E., et al.
(författare)
-
Research on stellarator-mirror fission-fusion hybrid
- 2014
-
Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 56:9, s. 094008-
-
Tidskriftsartikel (refereegranskat)abstract
- The development of a stellarator-mirror fission-fusion hybrid concept is reviewed. The hybrid comprises of a fusion neutron source and a powerful sub-critical fast fission reactor core. The aim is the transmutation of spent nuclear fuel and safe fission energy production. In its fusion part, neutrons are generated in deuterium-tritium (D-T) plasma, confined magnetically in a stellarator-type system with an embedded magnetic mirror. Based on kinetic calculations, the energy balance for such a system is analyzed. Neutron calculations have been performed with the MCNPX code, and the principal design of the reactor part is developed. Neutron outflux at different outer parts of the reactor is calculated. Numerical simulations have been performed on the structure of a magnetic field in a model of the stellarator-mirror device, and that is achieved by switching off one or two coils of toroidal field in the Uragan-2M torsatron. The calculations predict the existence of closed magnetic surfaces under certain conditions. The confinement of fast particles in such a magnetic trap is analyzed.
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| 37. |
- Mosharrof, Mohammad Sazzad, et al.
(författare)
-
An improved prediction model for the impact sound level of lightweight floors : Introducing decoupled floor-ceiling and beam-plate moment
- 2011
-
Ingår i: Acta Acoustica united with Acustica. - 1610-1928 .- 1861-9959. ; 97:2, s. 254-265
-
Tidskriftsartikel (refereegranskat)abstract
- To better understand the complex acoustic behaviour of lightweight building structures both experimental and theoretical approaches are necessary. Within the theoretical approach developing theoretical models is of great importance. The aim here is to further develop an existing method to predict the impact sound pressure level in a receiving room for a coupled floor structure where floor and ceiling are rigidly connected by beams. A theoretical model for predicting the impact sound level for a decoupled floor structure, which has no rigid mechanical connections between the floor and the ceiling, is developed. An analytical method has been implemented, where a spatial Fourier transform method as well as the Poisson's sum formula is applied to model transformed plate displacements. Radiated sound power was calculated from these displacements and normalized sound pressure levels were calculated in one-third octave frequency bands. The predicted results from the model are compared with the results from the experiments on the decoupled floor-ceiling construction. The results gave agreements in line with comparisons regarding previous model. The effect of introducing beam-plate moment in the model is studied and is found to be dependent on frequency, showing significant improvement in predicting impact sound level at high frequency region.
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| 38. |
- Noack, Klaus, et al.
(författare)
-
Comments on the power amplification factor of a driven subcritical system
- 2013
-
Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 59, s. 261-266
-
Tidskriftsartikel (refereegranskat)abstract
- The power amplification factor PAF of a driven subcritical system is defined as the ratio of the fission power output of the blanket to the power which the driver must deliver to sustain its neutron source intensity. This parameter decisively determines the effectiveness of the whole system independent of its special purpose as energy amplifier or as transmutation facility. The present note derives a refined analytical expression for the PAF which reveals more physical details than the expressions given by other authors. Moreover, the traditionally used forms of the static reactor eigenvalue equation and of its adjoint equation are rewritten for subcritical systems and used in the derivation of the expression for the PAF. The derived formula and the modified eigenvalue equations are discussed.
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| 39. |
- Noack, Klaus, et al.
(författare)
-
Neutronic model of a mirror based fusion-fission hybrid for the incineration of spent nuclear fuel and with potential for power generation
- 2011
-
Konferensbidrag (refereegranskat)abstract
- In the last decade the Georgia Institute of Technology (Georgia Tech) published several design concepts of tokamak based fusion-fission hybrids which use solid fuel consisting of the transuranic elements of spent nuclear fuel from Light-Water-Reactors. The objectives of the hybrids are the incineration of the transuranic elements and additional net energy production. The paper presents a rough scientific design of the blanket of a mirror hybrid which was derived from the results of neutron transport calculations. The main operation parameters of two hybrid options were specified. One is the analog to Georgia Techs first version of a 'fusion transmutation of waste reactor" (FTWR) and the other is a possible near-term option which requires minimal fusion power.
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| 40. |
- Noack, Klaus, et al.
(författare)
-
Neutronic model of a mirror based fusion-fission hybrid for the incineration of the transuranic elements from spent nuclear fuel and energy amplification
- 2011
-
Ingår i: Annals of Nuclear Energy. - : Elsevier BV. - 0306-4549 .- 1873-2100. ; 38:2-3, s. 578-589
-
Tidskriftsartikel (refereegranskat)abstract
- The Georgia Institute of Technology has developed several design concepts of tokamak based fusion-fission hybrids for the incineration of the transuranic elements of spent nuclear fuel from Light-Water-Reactors. The present paper presents a model of a mirror hybrid. Concerning its main operation parameters it is in several aspects analogous to the first tokamak based version of a "fusion transmutation of waste reactor". It was designed for a criticality keff <= 0.95 in normal operation state. Results of neutron transport calculations carried out with the MCNP5 code and with the JEFF-3.1 nuclear data library show that the hybrid generates a fission power of 3 GWth requiring a fusion power between 35 and 75 MW, has a tritium breeding ratio per cycle of TBRcycle = 1.9 and a first wall lifetime of 12-16 cycles of 311 effective full power days. Its total energy amplification factor was roughly estimated at 2.1. Special calculations showed that the blanket remains in a deep subcritical state in case of accidents causing partial or total voiding of the lead-bismuth eutectic coolant. Aiming at the reduction of the required fusion power, a near-term hybrid option was identified which is operated at higher criticality keff <= 0.97 and produces less fission power of 1.5 GWth. Its main performance parameters turn out substantially better.
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| 41. |
- Noack, Klaus, et al.
(författare)
-
Safety And Power Multiplication Aspects Of Mirror Fusion-Fission Hybrids
- 2012
-
Ingår i: Fusion for Neutrons and Subcritical Nuclear Fission. - : AIP. - 9780735410381 ; , s. 186-198
-
Konferensbidrag (refereegranskat)abstract
- Recently, in a research project at Uppsala University a simplified neutronic model for a straight field line mirror hybrid has been devised and its most important operation parameters have been calculated under the constraints of a fission power production of 3 GW and that the effective multiplication factor k(eff) does not exceed 0.95. The model can be considered as representative for hybrids driven by other types of mirrors too. In order to reduce the demand on the fusion power of the mirror, a modified option of the hybrid has been considered that generates a reduced fission power of 1.5 GW with an increased maximal value k(eff) = 0.97. The present paper deals with nuclear safety aspects of this type of hybrids. It presents and discusses calculation results of reactivity effects as well as of driver effects.
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| 42. |
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| 43. |
- Olsson, Per-Anders, 1971, et al.
(författare)
-
Modelling of the GIA-induced surface gravity change over Fennoscandia
- 2012
-
Ingår i: Journal of Geodynamics. - : Elsevier BV. - 0264-3707. ; 61, s. 12-22
-
Tidskriftsartikel (refereegranskat)abstract
- This paper deals with the modelling of surface gravity change in Fennoscandia, induced by postglacial rebound or Glacial Isostatic Adjustment (GIA). The theoretical foundation is based on the theory introduced by [Peltier, 1974] and [Peltier, 1976] for a spherical, non-rotating, laterally homogenous, viscoelastic, Maxwell Earth and the solution of the Sea Level Equation, originally introduced by Farrel and Clark (1976), with time-dependent coastline geometry. The ice history is defined by the ice model ICE-5G. Rotational feedback is not included.The sensitivity of predictions of present day gravity rates View the MathML source, with respect to a selection of assumptions and approximations, is investigated numerically. Six model variants are defined: (i) linear relation between View the MathML source and the vertical deformation rate View the MathML source, (ii) direct attraction expressed in terms of internal and (iii) external harmonic series expansions as well as by (iv) analytical integration over rectangular prisms. For the most rigorous treatment of the direct attraction, the effect of simplified modelling of the sea level is also investigated. These modelling approximations of the sea level change include (v) fixed shorelines and (vi) eustatic sea level change. Predictions of View the MathML source for the model variants are plotted, compared and discussed.The most rigorous model (iv) and the linear model (i) differ less than 0.03 μGal yr−1 over land and close to, or over, the ocean the difference reaches maximally ∼0.5 μGal yr−1. Due to truncation at 180°, the high frequent nature of the direct attraction is not properly described by models (ii) and (iii). The two simplified sea level modelling approximations (v) and (vi) induce differences, compared to the most rigorous model exceeding 0.2 μGal yr−1 over land, i.e. about one order of magnitude worse than the linear model.
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| 44. |
- Olsson, Per-Anders, 1971, et al.
(författare)
-
The relation between gravity rate of change and vertical displacement in previously glaciated areas
- 2015
-
Ingår i: Journal of Geodynamics. - : Elsevier BV. - 0264-3707. ; 83, s. 76-84
-
Tidskriftsartikel (refereegranskat)abstract
- The rate of change of surface gravity, dg/dt, and vertical deformation rate of the solid surface, du/dt, are two observables of glacial isostatic adjustment (GIA). They contribute with different information on the same phenomenon. Their relation contains information of the underlying physics and a trustworthy relation allows to combine these observations to strengthen the overall observational accuracy of the phenomenon. In this paper we investigate the predicted relation between dg/dt and du/dt in previously glaciated areas. We use the normal mode approach for one dimensional earth models and solutions of the sea level equation with time-dependent coastline geometry. Numerical predictions of dg/dt and du/dt are computed for Laurentia, Fennoscandia and the British Isles respectively, using six different earth models. Within each region a linear trend is then fitted using the relation dg/dt = C du/dt + dg_0/dt. The estimated C and dg_0/dt differ more between the regions than between different earth models within each region. For Fennoscandia C ≈ −0.163 μGal/mm and for Laurentia C ≈ −0.152 μGal/mm. Maximum residuals between the linear trend and spatially varying model predictions of dg/dt are 0.04 μGal/yr in Fennoscandia and 0.17 μGal/yr in Laurentia. For the British Isles the results are harder to interpret, mainly since this region is located on the zero uplift isoline of Fennoscandia. In addition, we show temporal variation of the relation since the last glacial maximum till present-day. The temporal and spatial variation of the relation between dg/dt and du/dt can be explained by (i) the elastic respectively viscous proportion of the total signal and (ii) the spectral composition of the regional signal. Additional local effects, such as the Newtonian attraction and elastic deformation from local sea level changes, are examined in a case study for six stations in the Nordic absolute gravity network. The influence of these local effects on the relation between View the dg/dt and du/dt is negligible except for extreme locations close to the sea.
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| 45. |
- Pelliccione, Patrizio, 1975, et al.
(författare)
-
A proposal for an Automotive Architecture Framework for Volvo Cars
- 2016
-
Ingår i: Workshop on Automotive Systems/Software Architectures (WASA), Venice, Italy, April 05-08, 2016. - 9781509025718 ; , s. 18-21
-
Konferensbidrag (refereegranskat)abstract
- © 2016 IEEE. During the past twenty years vehicles have become more and more robot like, interpreting and exploiting input from various sensors to make decisions and finally commit actions that were previously made by humans. Such features will require continuous evolution and updates to ensure safety, security, and suitability for supporting drivers in an ever changing world. Modern vehicles can have over 100 Electronic Control Units (ECUs), which are small computers, together executing gigabytes of software. ECUs are connected to each other through severalnetworks within the car, and in some cases also to the outside world. This need for addressing ever increasing complexity as well as for offering flexibility, support of continuous evolution, and very late changes in user visible features introduces new challenges for developing and maintaining a suitable electronic architecture. In this paper we report the current investigation of the Volvo Cars to create an architecture framework tailored to the needs of future vehicles.
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| 46. |
- Pelliccione, Patrizio, 1975, et al.
(författare)
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Architecting cars as constituents of a system of systems
- 2016
-
Ingår i: ACM International Conference Proceeding Series. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450363990 ; , s. 1-7
-
Konferensbidrag (refereegranskat)abstract
- Future transportation systems will be a heterogeneous mix of items with varying connectivity and interoperability. A mix of new technologies and legacy systems will co-exist to realize a variety of scenarios involving not only connected cars but also road infrastructures, pedestrians, cyclists, etc. Future transportation systems can be seen as a System of Systems (SoS), where each constituent system - one of the units that compose an SoS - can act as a standalone system, but the cooperation among the constituent systems enables new emerging and promising scenarios. In this paper we investigate how to architect cars so that they can be constituents of future transportation systems. This work is realized in the context of two Swedish projects coordinated by Volvo Cars and involving some universities and research centers in Sweden and many suppliers of the OEM, including Autoliv, Arccore, Combitech, Cybercom, Knowit, Prevas, ÅF-Technology, Semcom, and Qamcom.
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| 47. |
- Pelliccione, Patrizio, et al.
(författare)
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Automotive Architecture Framework: the experience of Volvo Cars
- 2017
-
Ingår i: Journal of systems architecture. - : Elsevier BV. - 1383-7621. ; 77, s. 83-100
-
Tidskriftsartikel (refereegranskat)abstract
- The automotive domain is living an extremely challenging historical moment shocked by many emerging business and technological needs. Electrication, autonomous driving, and connected cars are some of the driving needs in this changing world. Increasingly, vehicles are becoming software-intensive complex systems and most of the innovation within the automotive industry is based on electronics and software. Modern vehicles can have over 100 Electronic Control Units (ECUs), which are small computers, together executing gigabytes of software. ECUs are connected to each other through several networks within the car, and the car is increasingly connected with the outside world. These novelties ask for a change on how the software is engineered and produced and for a disruptive renovation of the electrical and software architecture of the car. In this paper we describe the current investigation of Volvo Cars to create an architecture framework able to cope with the complexity and needs of present and future vehicles. Specically, we present scenarios that describe demands for the architectural framework and introduce three new viewpoints that need to be taken into account for future architectural decisions: Continuous Integration and Deployment, Ecosystem and Transparency, and car as a constituent of a System of Systems. Our results are based on a series of focus groups with experts in automotive engineering and architecture from dierent companies and universities.
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| 48. |
- Sandström, Alfred, et al.
(författare)
-
Förvaltning av signalkräfta i sjöar : en litteraturstudie
- 2013
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Fisket efter signalkräfta har fått allt större ekonomisk och social betydelse i Sverige. Trots detta saknas väl underbyggda råd för hur ett hållbart fiske ska bedrivas. Projektet ”Utveckling av fisket efter signalkräfta – hur ska man optimera fiske och förutsäga risken för populationskollapser?” är ett projekt som delfinansieras av Europeiska fiskerifonden 2009-2013. Som en inledande del i detta projekt gjordes en litteratursammanställning, och baserat på denna har planeringen av det framtida arbetet kunnat konkretiseras. Målsättningen med litteraturgenomgången var att identifiera vilken information om signalkräftans biologi och ekologi som behövdes för att kunna ta fram bra fiskerimodeller för hur ett hållbart fiske bör bedrivas. Dessutom var det viktigt att förstå varför vissa bestånd av signalkräfta har kollapsat. Fångsterna av signalkräfta varierar mellan sjöar. Denna variation kan, i sjöar som inte är försurade, till stor del förklaras med hur stor andel av sjöns botten som är täckt med sten. Finns det mycket sten i en sjö finns det också mycket signalkräftor. Det finns några få studier i Sverige på signalkräftan där populationer har följts under en längre tid (minst 15 år). Dessa visar att fångst per mjärde och uttag av konsumtionskräftor varierar mellan olika år inom en sjö. Dessa variationer kan till viss del förklaras med temperaturen under föregående år, men mekanismen bakom detta är inte känd. Studier av andra arter sötvattenskräftor och en del marina skaldjur (t.ex. hummer) tyder på att rekryteringen (reproduktionsframgången) till viss del kan förklara variationerna i fångstnivåer mellan olika år. Denna litteraturgenomgång visar att det saknas väsentlig information om signalkräftans ekologi och biologi för att kunna ta fram teoretiska modeller som ska ligga till grund för rekommendationer om hur ett hållbart fiske ska bedrivas. De beståndsanalyser som bedömts vara intressanta för signalkräfta kräver vissa dataunderlag för att ge tillförlitliga resultat. De enskilt viktigaste faktorerna är rekryteringsframgång, tillväxt, naturlig dödlighet, och detaljerad fiskeristatistik (ansträngning, selektivitet, fångster etc.). Med anledning av resultaten från denna litteraturgenomgång bedömdes följande insatser som prioriterade: • undersöka betydelsen av honans storlek för rekryteringsframgång • utveckla tekniken för märkning av kräftor i olika typer av bestånd för att sedan kunna använda återfångstdata för att bestämma individuell tillväxt, naturlig dödlighet och fiskeridödlighet • uppskatta ytan tillgängligt kräfthabitat för olika kräftbestånd och bedöma i vilken mån det påverkar potentiellt fiskeuttag • analysera ett flertal sjöar med och utan populationskollapser och undersöka vilka miljöfaktorer som kan förklara uppkomsten av kollapser • analysera såväl pestfrekvens som infektionsgrad i enskilda kräftor och utvärdera om det finns en koppling mellan populationskollapser och ökade pestangrepp i sjöar
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| 49. |
- Wigenstam, Elisabeth, et al.
(författare)
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Anti-inflammatory and anti-fibrotic treatment in a rodent model of acute lung injury induced by sulfur dioxide
- 2018
-
Ingår i: Clinical Toxicology. - : Taylor & Francis. - 1556-3650 .- 1556-9519. ; 56:12, s. 1185-1194
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Tidskriftsartikel (refereegranskat)abstract
- Context: Inhalation of sulfur dioxide (SO2) affects the lungs and exposure to high concentrations can be lethal. The early pulmonary response after inhaled SO2 involves tissue injury, acute neutrophilic lung inflammation and airway hyperresponsiveness (AHR). In rats, long-term pulmonary fibrosis is evident 14 days post-exposure as indicated by analysis of collagen deposition in lung tissue. Early treatment with a single dose of dexamethasone (DEX,10 mg/kg) significantly attenuates the acute inflammatory response in airways. However, this single DEX-treatment is not sufficient for complete protection against SO2-induced injuries.Methods: Female Sprague–Dawley rats exposed to SO2 (2200 ppm, nose-only exposure, 10 min) were given treatments (1, 5 and 23 h after SO2-exposure) with the anti-fibrotic and anti-inflammatory substance Pirfenidone (PFD, 200 mg/kg) or DEX (10 mg/kg) to evaluate whether the inflammatory response, AHR and lung fibrosis could be counteracted.Results: Both treatment approaches significantly reduced the total leukocyte response in bronchoalveolar lavage fluid and suppressed pulmonary edema. In contrast to DEX-treatment, PFD-treatment reduced the methacholine-induced AHR to almost control levels and partially suppressed the acute mucosal damage whereas multiple DEX-treatment was the only treatment that reduced collagen formation in lung tissue.Conclusions: To enable an accurate extrapolation of animal derived data to humans, a detailed understanding of the underlying mechanisms of the injury, and potential treatment options, is needed. The findings of the present study suggest that treatments with the capability to reduce both AHR, the inflammatory response, and fibrosis are needed to achieve a comprehensive mitigation of the acute lung injury caused by SO2.
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- Xu, Bo, et al.
(författare)
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AgTFSI as p-Type Dopant for Efficient and Stable Solid-State Dye-Sensitized and Perovskite Solar Cells
- 2014
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 7:12, s. 3252-3256
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Tidskriftsartikel (refereegranskat)abstract
- A silver-based organic salt, silver bis(trifluoromethane-sulfonyl) imide (AgTFSI), was employed as an effective p-type dopant for the triarylamine-based organic hole-transport material Spiro-MeOTAD, which has been successfully applied in solid-state dye-sensitized solar cells (ssDSCs) and perovskite solar cells (PSCs). The power conversion efficiencies (PCEs) of AgTFSI-doped devices improved by 20%, as compared to the device based on the commonly used oxygen doping both for ssDSCs and PSCs. Moreover, the solid-state dye-sensitized devices exposed to AgTFSI as dopant showed considerably better stability than those of oxygen doped, qualifying this p-type dopant as a promising alterative for the preparation of highly efficient as well as stable ssDSCs and PSCs for the future.
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