| 1. |
- Hagstrom, Emil, et al.
(författare)
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IMPACT OF BODY WEIGHT AT AGE 20 AND WEIGHT GAIN DURING ADULTHOOD ON MIDLIFE CORONARY ARTERY CALCIUM IN 15,000 MEN AND WOMEN : AN INTERIM ANALYSIS OF THE SWEDISH CARDIOPULMONARY BIOIMAGE STUDY
- 2019
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Ingår i: Journal of the American College of Cardiology. - : ELSEVIER SCIENCE INC. - 0735-1097 .- 1558-3597. ; 73:9, s. 1692-1692
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- BackgroundElevated body weight in adolescence is strongly associated with early cardiovascular disease, but whether this association is traceable to weight in early adulthood, or to weight gain with subsequent high adult weight is not known. Using data from the Swedish CArdioPulmonary bioImage Study (SCAPIS), we investigated the association between weight at age 20, weight gain to midlife and coronary artery calcium score (CACS) at midlife.MethodsIn the first 15,810 participants in SCAPIS (mean age 58 years, 52% women), data on CACS at midlife, self-reported body weight at age 20 and weight at examination in SCAPIS were recorded.ResultsCACS in midlife was significantly higher with increasing weight at age 20 (p<0.001 for both sexes), and then increased with weight gain until midlife at all levels of body weight at age 20 after adjusting for age, height, smoking, alcohol intake, education level, exercise levels and LDL cholesterol. However, the association with weight gain was only significant in men (p = 0.047), not in women (p=0.474). No significant interaction was seen between weight at age 20 and midlife weight with CACS. The effect of weight at age 20 on CACS was significantly more marked in men than in women, as was the effect of weight gain (p<0.001 for both interactions).ConclusionWeight at age 20 and weight gain to midlife were both related to CACS, but much more markedly so in men than in women, indicating a generally larger effect of both early adult weight and further weight gain until midlife on CACS in men, compared to women.
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| 2. |
- Leander, John, et al.
(författare)
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A calibrated verification model for fatigue assessment of road bridges
- 2019
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Ingår i: Proceeding of Nordic Steel 2019. - : Wiley.
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Konferensbidrag (refereegranskat)abstract
- The format suggested in the Eurocode for fatigue verification of road bridges is under scrutiny in thispaper. The model is easy to use in practice, which is important for design purposes, but its accuracyhas been questioned. For this reason, a reliability-based evaluation of the safety level has beenperformed and is briefly recapitulated in this paper. It shows a large scatter in reliability index rangingfrom unacceptably low to overly conservative. A calibration of the existing model has been performedshowing a more consistent reliability level. Results from comparisons of the existing and calibratedmodels are shown for real bridges considering the influence on design stress ranges. The results showthat the Eurocode model is conservative for short span bridges subjected to low traffic volume. Forother cases, the Eurocode model is non-conservative.
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| 3. |
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| 4. |
- Nekouei, Ehsan, et al.
(författare)
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Optimal Decision Fusion Under Order Effects
- 2019
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Ingår i: IFAC PAPERSONLINE. - : ELSEVIER SCIENCE BV. - 2405-8963. ; , s. 53-60
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Konferensbidrag (refereegranskat)abstract
- This paper studies an optimal decision fusion problem with a group of human decision makers when an order effect is present. The order effect refers to situations wherein the process of decision making by a human is affected by the order of decisions. In our set-up, all human decision makers, called observers, receive the same data which is generated by a common but unknown hypothesis. Then, each observer independently generates a sequence of decisions which are modeled by employing non-commutative probabilistic models of the data and their relation to the unknown hypothesis. The use of non-commutative probability models is motivated by recent psychological studies which indicate that these non-commutative probability models are more suitable for capturing the order effect in human decision making, compared with the classical probability model. A central decision maker (CDM) receives (possibly a subset of) the observers' decisions and decides on the true hypothesis. The considered problem becomes an optimal decision fusion problem with observations modeled using a non-commutative (Von Neumann) probability model. The structure of the optimal decision rule at the CDM is studied under two scenarios. In the first scenario, the CDM receives the entire history of the observers' decisions whereas in the second scenario, the CDM receives only the last decision of each observer. The perfromance of the optimal fusion rule is numerically evaluated and compared with the optimal fusion rule derived when using a classical probability model.
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| 5. |
- Skoglund, Oskar
(författare)
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Innovative structural details using high strength steel for steel bridges
- 2019
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of high strength steel has the potential to reduce the amount of steel used in bridge structures and thereby facilitate a more sustainable construction. The amount of steel and what steel grade that can be used in bridge structures and other cyclic loaded structures are often limited by a material degradation process called fatigue. The fatigue resistance of steel bridges are to a large extent depending on the design of structural details and connections. The design engineer is limited by a few pre-existing structural details and connections – with rather poor fatigue resistance – to choose from when designing steel bridges, and is therefore often forced to increase the overall dimensions of the structure in order to cope with the design requirements of fatigue. This licentiate thesis aims at increasing the fatigue resistance of fatigue prone structural details and connections by implementing new and innovative structural solutions to the already pre-existing details given in the design standards. A typical fatigue prone detail is the vertical stiffener at an intermediate cross-beam, which will be in focus. By improving the fatigue resistance, less steel material will be required for the construction of new steel bridges and composite bridges of steel and concrete. It is shown in this thesis and the appended papers that the use of high strength steel for bridge structures can considerably reduce the amount of steel used, the steel cost and the harmful emissions. However, this is only true if the fatigue strength of critical details can be substantially improved. Furthermore, a few new and innovative structural details and modifications to already existing details are proposed in this thesis and in the appended papers, that have the potential to increase the fatigue resistance of steel bridges and composite bridges of steel and concrete. However, further analyses are required in order to make these structural details viable for construction.
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| 6. |
- Skoglund, Oskar, et al.
(författare)
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The impact of local geometry on the fatigue life of a welded structural detail
- 2019
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Ingår i: Proceeding of Nordic Steel 2019.
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Konferensbidrag (refereegranskat)abstract
- Fatigue often limits the capacity of welded steel bridges, and thus often governs the amount of steel required. The fatigue life is, to a large extent, governed by stress concentrations and the magnitude is controlled by local as well as global geometry; by improving the local geometry the stress raising effects can be lowered and by increasing the global dimensions the nominal stress can be reduced. The fatigue assessment format presented in the Eurocode gives little or no room for the designer to control the local geometry of the structural detail, and is often left with increasing the overall dimensions in order to improve the fatigue life of the structure. This paper aims at investigating the possible impact on the fatigue life of welded steel structures by different weld geometries. In this paper a vertical stiffener will be studied by fracture mechanics. The study showed that significant improvements in fatigue life can be made by small changes to the weld geometry and the most pronounced effect was by changing the weld toe radius, and
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