SwePub - sökning: WFRF:(Sjölander Anders)

Numrering	Referens	Omslagsbild	Hitta
1.	Günther, Torsten, et al. (författare) Population genomics of Mesolithic Scandinavia : Investigating early postglacial migration routes and high-latitude adaptation 2018 Ingår i: PLoS biology. - : Public Library of Science (PLoS). - 1544-9173 .- 1545-7885. ; 16:1 Tidskriftsartikel (refereegranskat)abstract Scandinavia was one of the last geographic areas in Europe to become habitable for humans after the Last Glacial Maximum (LGM). However, the routes and genetic composition of these postglacial migrants remain unclear. We sequenced the genomes, up to 57x coverage, of seven hunter-gatherers excavated across Scandinavia and dated from 9,500-6,000 years before present (BP). Surprisingly, among the Scandinavian Mesolithic individuals, the genetic data display an east-west genetic gradient that opposes the pattern seen in other parts of Mesolithic Europe. Our results suggest two different early postglacial migrations into Scandinavia: initially from the south, and later, from the northeast. The latter followed the ice-free Norwegian north Atlantic coast, along which novel and advanced pressure-blade stone-tool techniques may have spread. These two groups met and mixed in Scandinavia, creating a genetically diverse population, which shows patterns of genetic adaptation to high latitude environments. These potential adaptations include high frequencies of low pigmentation variants and a gene region associated with physical performance, which shows strong continuity into modern-day northern Europeans.
2.	Sjölander, Anders (författare) Den naturliga ordningen : Makt och intressen i de svenska sparbankerna 1882-1968 2003 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract The aim of this thesis has been to analyse how savings banks were integrated into the Swedish financial system from the end of the 19 th century until 1968. The study has focused on two questions. The fist deals with different viewpoints regarding the role of Savings banks in the credit market and which of these viewpoints had an impact on the regulation of savings banks. The second questions studied in this thesis concerns which actors had control over the savings banks and their regulation. In this thesis I have shown that the question of the role of savings banks in the financial system is complex. During the entire period being studied, savings banks were local organisations and the ideas that were put forward regarding their role on the credit market were greatly affected by how the credit market were organised on the local level. Sudden changes were rare within the savings banks' movement. As I have shown, during the period being studied, there were many different points of view regarding the role of savings banks in the financial system. Without outside pressure in the form of legislation, however, the savings banks themselves would hardly have succeeded in agreeing on and developing new operations. The slow but apparent changes in the position of savings banks on the Swedish financial market were closely connected to changes in power structures in Swedish society. Up until the inter-war period, the local elite - both economic and political - were closely involved with the development of savings banks. Gradually, however, national elite groups, that is political parties and the savings banks' central organisation, increased their control over local savings banks. At the same time as this change strengthened the role of savings banks as in some measure a public organisation, it also helped to expand their sphere of activity.
3.	Ahlm, Kristin, et al. (författare) Unnatural deaths in reindeer-herding Sami families in Sweden, 1961-2001 2010 Ingår i: International Journal of Circumpolar Health. - 1239-9736 .- 2242-3982. ; 69:2, s. 129-137 Tidskriftsartikel (refereegranskat)abstract OBJECTIVES: Unnatural deaths among Indigenous populations, including the Swedish Sami, occur more often than among the general population. To find prevention strategies, we explored the circumstances of the unnatural deaths of members of reindeer-herding Sami families.STUDY DESIGN: The number of deaths from among a cohort of 7,482 members of reindeer-herding Sami families were retrieved from the National Board of Health and Welfare for the years 1961- 2001.METHODS: An evaluation of the information from autopsy records at the National Board of Forensic Medicine, police reports, and available medical records identified 158 unnatural deaths. These were then analysed in detail.RESULTS: Transport-related deaths and suicides were the most common unnatural deaths among Swedish reindeer-herding Sami family members. Suicides contributed to 23% of all deaths, road traffic accidents to 16%, and snowmobile fatalities to 11%. The accidents generally reflected an "outdoor lifestyle" and the working conditions were characterized by the use of off-road vehicles such as snowmobiles. Half of the number of victims tested positive for alcohol and alcohol abuse was documented in 15% of all victims.CONCLUSIONS: The results indicate that alcohol is an important factor in preventing unnatural deaths among reindeer-herding Sami, together with increased safety of both on-road and off-road transportation.
4.	Ahmed, Lamis, et al. (författare) Evaluation and analysis of laboratory tests of bolts-anchored, steel-fiber-reinforced shotcrete linings 2017 Ingår i: Proceedings of the World Tunnel Congress 2017. - : International Tunnelling Association. Konferensbidrag (refereegranskat)abstract Results from laboratory tests on statically loaded bolt-anchored, steel-fibre-reinforced shotcrete linings in interaction with rock are here evaluated using a 2D finite element model. Calculations are made to determine the state of stress in the rock-shotcrete interface near the rock joints. Plane-stress elements are used with a non-linear material model, capable of describing cracking and de-bonding during loading. The simulated crack position and force-displacement curves are compared with laboratory test results. Since most construction work in underground hard rock involves the use of explosives for excavation work, dynamic load cases are also analysed and compared to results from previous research on vibration resistance of shotcrete.
5.	Andersson, Malin E, 1978, et al. (författare) Kinesin gene variability may affect tau phosphorylation in early Alzheimer's disease. 2007 Ingår i: International journal of molecular medicine. - 1107-3756 .- 1791-244X. ; 20:2, s. 233-9 Tidskriftsartikel (refereegranskat)abstract Kinesin is a microtubule-associated motor protein that transports Alzheimer-associated amyloid precursor protein (APP) in neurons. In animal models, impaired kinesin-mediated APP transport seems to enhance formation of the neurotoxic 42 amino acid fragment of beta-amyloid (A beta 42). In man, one study suggests that a polymorphism (rs8702, 56,836G>C) in the kinesin light chain 1 gene (KNS2) may affect the risk of Alzheimer's disease (AD). To further assess KNS2 as a susceptibility gene for AD we analyzed 802 patients with sporadic AD and 286 controls, 134 longitudinally followed patients with mild cognitive impairment (MCI) and 39 cognitively stable controls for the rs8702 polymorphism. The rs8702 polymorphism did not influence risk of AD (p=0.46). However, rs8702 interacted with APOE epsilon 4 carrier status in AD (p=0.006) and influenced cerebrospinal fluid levels of hyperphosphorylated tau in MCI patients who converted to AD during follow-up (p=0.018). These findings support earlier indications that genetic variability in the KNS2 gene may play a role during early stages of AD pathogenesis.
6.	Ansell, Anders, et al. (författare) Load bearing capacity for tunnel shotcrete with various fibre types and materials 2022 Ingår i: Proceedings 6th fib International Congress on Concrete Innovation for Sustainability. - : fib. The International Federation for Structural Concrete. Konferensbidrag (refereegranskat)abstract Reducing the environmental impact from tunnel construction put focus on finding alternative designs for rock support based on fibre reinforced shotcrete (sprayed concrete). Different types and materials for fibres for use in shotcrete are developed and new methods for control of the load-bearing capacity and new techniques for material investigation in laboratory environments are tested. In an ongoing project the behaviours under flexural loading for shotcrete with some fibres of typical geometries and materials are compared through testing of Round Determinate Panels. For the tested dosages of fibres, the highest energy absorption capacity was for steel fibres, with macro synthetic and basalt fibres showing similar but lower results. The efficiency of fibres depends on the numbers crossings a crack and how these are oriented vs tensile stresses. Computed tomography (CT) X-ray scanning is now used in the laboratory for visualization of the interior of shotcrete samples. Examples from examination of steel fibre orientation in test cores are given.
7.	Ansell, Anders, et al. (författare) Statiska beräkningar och analyser avseende betongplatta i Spendrups höglager 2015 Rapport (övrigt vetenskapligt/konstnärligt)
8.	Ansell, Anders, et al. (författare) Tunnel Shotcrete Performance due to Varying Thickness and Bond to Hard Rock 2022 Ingår i: The 47th ITA-AITES World Tunnel Congress, Copenhagen, Denmark, 5-8 September, 2022. Konferensbidrag (refereegranskat)abstract The structural behaviour of fibre reinforced shotcrete (sprayed concrete) as support in hard rock tunnels are complex and depends on the interaction between shotcrete, bolts and rock. It is here studied how variations in shotcrete thickness and bond strength affect the behaviour of this type of rock support system. Numerical models are used to simulate bond failure, shotcrete cracking and pull-out of grouted rock bolts. It is shown that local variations in shotcrete thickness affects possible shrinkage crack patterns and when subjected to the load from a loose block, the force is transferred to the surrounding rock through bond stresses distributed over a narrow band in the shotcrete. Moreover, it is shown how the structural capacity with respect to bond failure depends on the shotcrete thickness.
9.	Bjerg, Anders, 1982, et al. (författare) Increase in pollen sensitization in Swedish adults and protective effect of keeping animals in childhood 2016 Ingår i: Clinical and Experimental Allergy. - : Wiley. - 0954-7894 .- 1365-2222. ; 46:10, s. 1328-1336 Tidskriftsartikel (refereegranskat)abstract BACKGROUND: To date, most studies of the "allergy epidemic" have been based on self-reported data. There is still limited knowledge on time trends in allergic sensitization, especially among adults.OBJECTIVE: To study allergic sensitization, its risk factors, and time trends in prevalence.METHODS: Within West Sweden Asthma Study (WSAS) a population-based sample of 788 adults (17-60y) underwent skin prick tests (SPT) for 11 aeroallergens 2009-2012. Specific IgE was analyzed in 750 of the participants. Those aged 20-46y (n=379) were compared with the European Community Respiratory Health Survey sample aged 20-46y from the same area (n=591) in 1991-1992.RESULTS: Among those aged 20-46y the prevalence of positive SPT to pollen increased; timothy from 17.1% to 29.0% (p<0.001) and birch from 15.6% to 23.7% (p=0.002) between 1991-1992 and 2009-2012. Measurements of specific IgE confirmed these increases. Prevalence of sensitization to all other tested allergens was unchanged. In the full WSAS sample aged 17-60y any positive SPT was seen in 41.9%, and the dominating sensitizers were pollen (34.3%), animals (22.8%) and mites (12.6%). Pollen sensitization was strongly associated with rhinitis, whereas indoor allergens were more associated with asthma. Growing up with livestock or furred pets decreased the risk of sensitization, adjusted odds ratio 0.53 (0.28-0.995) and 0.68 (0.47-0.98) respectively.CONCLUSION: Pollen sensitization has increased in Swedish adults since the early 1990's, while the prevalence of sensitization to other allergens has remained unchanged. This is one plausible explanation for the increase in rhinitis 1990-2008 in Swedish adults, during which time the prevalence of asthma, which is more associated with perennial allergens, was stable. Contact with animals in childhood seems to reduce the risk of sensitization well into adulthood. One major factor contributing to the rise in pollen allergy is a significant increase in levels of birch and grass pollen over the past three decades.
10.	Bryne, Lars Elof, et al. (författare) Load-bearing capacity for shotcrete of various fibre types and curing sequences 2022 Konferensbidrag (refereegranskat)
11.	Enzell, Jonas, et al. (författare) Modellförsök stärker betongdammars säkerhet 2023 Ingår i: Bygg och Teknik. - 0281-658X .- 2002-8350. ; 115:6 Tidskriftsartikel (populärvet., debatt m.m.)abstract Dammhaverier är mycket ovanliga och därför är kunskapen om brottförloppet vid ett potentiellt dammbrott begränsad. Uppstår brottet utan förvarning, eller finns tidiga tecken på allvarliga problem? Hur utvecklas brottsbräschen under brottförloppet? Detta är frågor som blivit än mer aktuella efter tre internationella dammhaverier under 2023. För att söka svar har en serie skalmodellförsök utförts där haverier av betongdammar simuleras. En viktig parameter vid säkerhetsbedömningen av en betongdamm består i att utvärdera dess stabilitet. Förenklat görs dettag enom att jämföra om dammkroppens vikt är tillräcklig för att stå emot lasten från vattnets tryck. Traditionellt beaktas enbart en mindre del av en betongdamm när dess stabilitet utvärderas men de nya försöken indikerar att det vore eftersträvansvärt att undersöka hela dammen samtidigt eftersom lasten fördelas mellan konstruktionsdelarna. Många betongdammars tillstånd övervakas idag genom automatiska mätningarav till exempel vattenstånd, förskjutningar och grundvattentryck. Dock finns det ingen standardiserad metod för att definiera larmgränser,vilket detta projekt syftar till att utveckla i framtiden.
12.	Enzell, Jonas, et al. (författare) Physical Model Tests of Concrete Buttress Dams with Failure Imposed by Hydrostatic Water Pressure 2023 Ingår i: Water. - : MDPI. - 2073-4441. ; 15:20 Tidskriftsartikel (refereegranskat)abstract Although the failure of a concrete dam is a complex and highly dynamic process, the current safety assessments of concrete gravity and buttress dams rely on a simplified 2D stability analysis, which neglects the load redistribution due to 3D monolith interactions and the valley shape. In addition, the estimation of breach parameters in concrete dams is based on assumptions rather than analyses, and better prediction methods are needed. Model tests have been conducted to increase the understanding of the failure behavior of concrete dams. A scale model buttress dam, with a scale of 1:15, consisting of 5 monoliths that were 1.2 m in height and 4 m in width, was constructed and loaded to failure using water pressure. The model dam had detachable abutment supports and shear keys to permit variations in the 3D behavior. The results showed that the shear transfer was large between the monoliths and that the failure of a single dam monolith is unlikely. A greater lateral restraint gives not only a higher failure load but also a better indication of impending failure. These findings suggest that the entire dam, including its boundary conditions, should be considered during a stability assessment. The results also suggest that the common assumption in dam safety codes that a single monolith fails during flooding analysis is not conservative. The dataset obtained provides a foundation for the future development of dam-monitoring alarm limits and for predictive models of dam-breaching processes.
13.	Enzell, Jonas, et al. (författare) Realistic numerical simulations of concrete dam failures 2023 Konferensbidrag (refereegranskat)abstract Dam failures may have catastrophic consequences, including the release of largeamounts of water, significant property damage, and loss of life. However, safety assessments ofconcrete gravity and buttress dams often rely on simplified methods that do not consider the interactionbetween monoliths, the shape of the foundation or the presence of stiff abutments. Numericalmodeling can be a valuable tool for analyzing the stability of these dams, but it can bedifficult to validate these models due to a lack of documented dam failures. This paper presentsthe results of a numerical study examining the ability of dynamic finite element analyses to simulatedam failures. The study used the results from a series of physical model tests as a case studyfor validation. It was found that the numerical model was able to accurately reproduce the failuremode and breach development observed in the physical model tests and capture the effect of theloading rate on the failure mode and time for the failure to develop. Simulations were also performedin prototype scale to verify that the model tests were representative of a real dam failure.Further research is needed to determine the reliability of the numerical models under differentloading conditions and in realistic geological settings. However, these findings suggest that numericalmodeling can be a valuable tool for analyzing the stability of concrete gravity and buttressdams and predicting the development of failures.
14.	Enzell, Jonas (författare) Toward Realistic Failure Evaluations for Concrete Buttress Dams 2023 Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract Concrete dams, complex structures supporting massive loads, have traditionally been assessed using simplified 2D analytical stability analyses based on the rigid body assumption. Previous studies have shown that 3D behavior, such as the interaction between the monoliths and the valley's geology, can greatly impact the load-bearing capacity of gravity dams but remains largely unexplored in buttress dams. Internal failure modes have also been shown to impact the load-bearing capacity and failure modes of concrete dams. The dam breach geometry and breach development time are important factors for flooding simulations used for emergency plans. There are no available methods for estimating the breach parameters for concrete dams. Instead, they are usually assumed based on simplified national recommendations, which introduces large uncertainties in the analysis. Thus, developing methods to estimate failure behavior in concrete gravity and buttress dams could significantly enhance flood simulation accuracy.This licentiate thesis aims to develop more realistic analysis methods for determining the load-bearing capacity and failure behavior of concrete buttress dams. To achieve this aim, studies using physical model tests were conducted to determine the 3D effects of the boundary conditions and the interaction between the monoliths and verify the results from finite element simulations. Numerical studies were performed to examine the failure behavior of concrete buttress dams and to determine suitable methods for such simulations. The results from the physical model tests suggest that 3D effects significantly impact the load-bearing capacity and the failure behavior of concrete buttress dams. Therefore, the entire dam should be considered in stability analyses rather than just single monoliths. The numerical studies showed that finite element models could successfully simulate dam failures, including the 3D behavior of concrete buttress dams and internal failure modes. However, there remain questions about the best methods for representing phenomena such as first-order roughness, valley shape, and fracture planes in these models.The model tests showed that while dam failures can occur abruptly with little to no initial signs of displacement, the presence of rough foundations, cohesion, and rock-strengthening measures in real-world dams suggests actual dam failures may not be as sudden. The results helped establish knowledge in the field to potentially create better alarm limits for automatic monitoring systems.
15.	Fjälling, Arne, 1950- (författare) The conflict between Grey seals (Halichoerus grypus) and the Baltic coastal fisheries : new methods for the assessment and reduction of catch losses and gear damage 2006 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract There is a problematic interaction going on between grey seals and the small scale coastal fisheries in the Baltic. A large number of seals are by-caught and drowned each year, and the viability of the fishery is threatened by catch losses caused by the seals. Traditional mitigation methods are not sufficient, or have in some cases not been properly evaluated. Available methods of quantifying and analysing the catch losses are also insufficient. This thesis consists of three parts, each studying a different angle of this conflict.In the first part, new models for estimating catch losses are presented. In addition to the commonly used method of counting the number of damaged fish in the nets, the new models also allow for an estimation of the hidden losses. Hidden losses may be fish that are completely removed from nets without leaving any traces, fish that escape through holes in the net torn by the seals, or even fish that are scared away from the fishing gear. Such losses were found to be significant, and hence it is now clear that the traditional models seriously underestimate the total losses. The new models also allow for a deeper analysis of the interaction process. The first presented model compares catches between adjacent days (day-pairs), the second uses nets that are pre-baited before deployment, and the third relies on a detailed inspection and repair of all seal-induced damage to the net meshes.In the second part, some traditional methods of mitigating the conflict are evaluated. A commercially available Acoustic Harassment Device was tested in a field trial. AHDs were deployed at several set-traps for salmonids for three consecutive years. The damage reducing effect was persistent throughout a season, as well as over the full three-year test period, and no “dinner bell” effect was observed. When seal attacks became frequent in the 1980´s, several of the traditional salmon traps were reinforced with newly developed extra strong net materials. These materials dramatically reduced the damage to the nets, and to some degree also the catch losses. However, the losses were still substantial, and the traditional gear was gradually phased out when better solutions emerged.In the third part, new methods of mitigating the conflict are evaluated. A salmon trap was built, using net meshes which were large enough to allow seal-chased fish to escape through, but which would still guide and confine non-stressed fish. The trap was fitted with a fish chamber with a double wall of very taut netting, separating the catch from the surroundings by a fixed distance. Interference by seals was significantly reduced with this construction. Field experiments revealed that seals used their above-water vision to locate and search out buoys of the type that are used in the fisheries. Larger buoys were more readily found than smaller. A set of trials was initiated where certain geographical areas were made unattractive for seals prior to their seasonal arrival to the region, by deploying stationary AHDs. Finally, aquarium experiments demonstrated that underwater vision and hearing were equally important in seals’ detection of fish in a test box. It was also found that there was a “near zone”, within which seals stayed focused on a fish and attempted to catch it by a quick thrust of the head. These studies strongly suggest that new seal-safe fishing gear and mitigation methods should be based on, and would benefit from, an in-depth understanding and analysis of natural seal behaviour.
16.	Fälting, Lars, et al. (författare) Both a borrower and a lender be : savings banks in the economic development of Sweden 1820-1939 2000 Rapport (övrigt vetenskapligt/konstnärligt)
17.	Gasch, Tobias, et al. (författare) A coupled multi-physics model for creep, shrinkage and fracture of early-age concrete 2016 Ingår i: 9th International Conference on Fracture Mechanics of Concrete and Concrete Structures. Konferensbidrag (refereegranskat)abstract The behaviour of concrete at early-age is complex and involves several physical fieldssuch as temperature, moisture and deformations. In this paper a hygro-thermo-chemo-mechanicalmodel for the analysis of early-age concrete based on a combination of models from the literature ispresented. The chemical model is based on the reaction degree concept, also used to define internal actions such as self-desiccation and ageing of mechanical properties. A mechanical model based on the Microprestress-Solidification theory for concrete creep is used, that in a simplified manner alsoconsiders concrete fracture. The model has been implemented in a numerical framework suitable for coupled multi-physics problems. It is here applied to a case study of an un-reinforced concrete tunnel plug made of a low-pH self-compacting concrete. Good agreement is generally obtained with measurements and hypotheses previously made on the behaviour of the plug are verified.
18.	Hanson, Lars, et al. (författare) Eye and Body Movements Characterised by Synchronised Sampling 1998 Ingår i: ; , s. 1-26 Konferensbidrag (refereegranskat)
19.	Hanson, Lars, et al. (författare) Mannequin Properties Desired for Ergonomic Evaluation of Car Interiors 1998 Ingår i: ; , s. 43-48 Konferensbidrag (refereegranskat)abstract Mannequin properties desired for ergonomic evaluation of car interiors Lars Hansson, Kenneth Holmqvist, Simon Sjölander, Giovanni Distante, Guiseppe Andreoni, Nicholas Colford, Tomas Engström, Gert-Åke Hansson, Roland Kadefors, Patric Petersson, Camilla Rigotti, Lena Sperling, Anders Sundin, Per Östman, Roland Akselsson The aim of this study was to simulate a future mannequin with real people in order to find characteristics necessary for ergonomic evaluation of comfort in car interiors. We argue that the mannequin should ideally perform natural movements, collision detection, a biomechanical model, and eyes. Optional improvements to the mannequin involve muscles and a heart. We also discuss the user interface to the mannequin and means to present mannequin data.
20.	Hansson, Lars, et al. (författare) Eye and Body Movements Characterized by Synchronized Sampling 1998 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract An example of a result from a long-term cooperation with Lund University (together with professor Roland Akselsson at the Department of Ergonomics and Aerosol Technology) there some of the authors. (Engström) gained extensive grants (EU-financing and Wallenberg Stifelsen regarding equipment as well as other founding from e.g. the Swedish Work Environment Found). This publication was a result of the just mentioned EU-financing.
21.	Hansson, Lars, et al. (författare) Mannequin Properties Desired for Ergonomic Evaluation of Car Interiors 1998 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract An example of a result from a long-term cooperation with Lund University (together with professor Roland Akselsson at the Department of Ergonomics and Aerosol Technology) there some of the authors. (Engström) gained extensive grants (EU-financing and Wallenberg Stifelsen regarding equipment as well as other founding from e.g. the Swedish Work Environment Found). This publication has emanated from an EU-financed research project.
22.	Hassler, Sven, et al. (författare) Cancer risk in the reindeer breeding Saami population of Sweden, 1961–1997 2001 Ingår i: European Journal of Epidemiology. - 0393-2990 .- 1573-7284. ; 17, s. 969-976 Tidskriftsartikel (refereegranskat)abstract The Saami people are the natives of northern Scandinavia and the Kola Peninsula. In a cohort of 2033 Swedish reindeer breeding Saamis, the cancer risks between 1961 and 1997 were studied. Intotal, 193 cases of cancer were observed versus 322 expected in the general Swedish population and 249 in a geographically matched reference population of non-Saamis. In comparison to non-Saamis living in the same area, the reindeer breeding Saamis showed astatistically significant lower risk of developing cancerofthe prostate and of malignant lymphoma, whereas the risk of stomach cancer was significantly higher. Although there were no statistically significant changes ofcancer risks over time, temporal trends were indicated towards a decreased risk of cancer in the stomach and the prostate. The results suggest that the explanations ofthe low cancer risk ofthe reindeer breeding Saamis, in relation to the non-Saamis in the same environment, are to be found among lifestyle and/or genetic factors
23.	Hassler, Sven, et al. (författare) Cancer risk in the reindeer breeding Saami population of Sweden, 1961–1997 2001 Ingår i: European Journal of Epidemiology. - 0393-2990 .- 1573-7284. ; 17:10, s. 969-976 Tidskriftsartikel (refereegranskat)abstract The Saami people are the natives of northern Scandinavia and the Kola Peninsula. In a cohort of 2033 Swedish reindeer breeding Saamis, the cancer risks between 1961 and 1997 were studied. In total, 193 cases of cancer were observed versus 322 expected in the general Swedish population and 249 in a geographically matched reference population of non-Saamis. In comparison to non-Saamis living in the same area, the reindeer breeding Saamis showed a statistically significant lower risk of developing cancer of the prostate and of malignant lymphoma, whereas the risk of stomach cancer was significantly higher. Although there were no statistically significant changes of cancer risks over time, temporal trends were indicated towards a decreased risk of cancer in the stomach and the prostate. The results suggest that the explanations of the low cancer risk of the reindeer breeding Saamis, in relation to the non-Saamis in the same environment, are to be found among lifestyle and/or genetic factors.
24.	Hellgren, Hilda och Sjölander, Anders (författare) Sparbankernas roll i den ekonomiska utvecklingen 1860 - 1939 1997 Ingår i: Ekonomisk historiska mötet 25 - 26 oktober. Konferensbidrag (övrigt vetenskapligt/konstnärligt)
25.	Hendrick, Stephanie, 1977- (författare) Beyond the Blog 2012 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract This dissertation examines weblog community as a materially afforded and socially constructed space. In a set of three case studies, this dissertation examines three separate weblog communities between 2004 and 2008. CASE STUDY I looks at knowledge management bloggers in order to better understand how bloggers form communities. In this case study, it will be shown that blogs group thematically and in temporal bursts. These bursts of thematic activity allow for movement in and out of a community, as well as act as a bridge between different weblog communities. CASE STUDY II examines two pseudonymous bloggers in order to better understand how presentation and identity is understood in blogging. It will be shown in CASE STUDY II that social identity in weblog communities is negotiated through blogging practices such as transparency in writing and truthful presentation. CASE STUDY III delves further into social identity by examining a community of academic bloggers and how traditional, institutionalized expectations influence social identity over time, and if this influence differs in the core and periphery of the community. It will be shown in CASE STUDY III that there is indeed a difference in how social identity is negotiated and performed between core and periphery members of a weblog community. Finally, a model towards an integrated approach to researching blogs is put forth.
26.	Holmberg, Henrik, 1976-, et al. (författare) Time to initiation of lipid-lowering drugs for subclinical atherosclerosis : sub-study of VIPVIZA randomized controlled trial, with single-arm cross-over 2022 Ingår i: European Heart Journal Open. - : Oxford University Press. - 2752-4191. ; 2:1 Tidskriftsartikel (refereegranskat)abstract AIMS: Visual information about subclinical atherosclerosis was provided to physicians and participants in the VIPVIZA trial, inclusion 2013-16 in northern Sweden, aiming to improve adherence to cardiovascular disease (CVD) prevention guidelines. Pictorial risk information may be more actionable. The aim of this study was to investigate the effect of intervention with pictorial risk information on time to first dispensing of statins.METHODS AND RESULTS: Asymptomatic atherosclerotic disease was screened for by carotid ultrasound examination in 3532 participants enrolled in VIPVIZA, of those 3000 met the criteria for this study. Participants were randomly assigned to receive pictorial risk information consisting of graphical representation of atherosclerosis as compared to a control group without intervention. Time to initiation of statins was assessed during 5 years of follow-up through the National prescribed drug register. After 3 years, both groups were re-examined and received the intervention information. In the intervention group, initiation of statins increased considerably for the first 3 years and a smaller increase was also seen after re-intervention. After the cross-over, the control group showed a sharp increase in initiation of statins, almost reaching the same proportion treated at 5 years. The propensity to initiate statin treatment increased over the study period and there was no difference between men and women.CONCLUSIONS: The pictorial information had an effect on time to initiation of statins, both as original and repeated intervention and also in the control group after single-arm cross-over. The current study supports pictorial information as a tool to shorten time to initiation of statins for CVD prevention.
27.	Holmdahl, Idun, et al. (författare) Inflammatory related plasma proteins involved in acute preschool wheeze 2023 Ingår i: Clinical and Translational Allergy. - : John Wiley & Sons. - 2045-7022. ; 13:11 Tidskriftsartikel (refereegranskat)abstract BackgroundPreschool wheeze is a risk factor for asthma development. However, the molecular mechanism behind a wheezing episode is not well understood.ObjectiveOur aims were to assess the association of plasma proteins with acute preschool wheeze and to study the proteins with differential expression at the acute phase at revisit after 3 months. Additionally, to investigate the relationship between protein expression and clinical parameters.MethodWe measured 92 inflammatory proteins in plasma and clinical parameters from 145 children during an episode of preschool wheeze (PW) and at the revisit after 3 months (PW-R, n = 113/145) and 101 healthy controls (HC) aged 6–48 months in the GEWAC cohort using the antibody-mediated proximity extension-based assay (Olink Proteomics, Uppsala).ResultsOf the 74 analysed proteins, 52 were differentially expressed between PW and HC. The expression profiles of the top 10 proteins, Oncostatin M (OSM), IL-10, IL-6, Fibroblast growth factor 21 (FGF21), AXIN1, CXCL10, SIRT2, TNFSF11, Tumour necrosis factor β (TNF-β) and CASP8, could almost entirely separate PW from HC. Five out of 10 proteins were associated with intake of oral corticosteroids (OCS) 24 h preceding blood sampling (OSM, CASP8, IL-10, TNF-β and CXCL10). No differences in protein expression were seen between PWs with or without OCS in comparison to HC. At the revisit after 3 months, differential protein expressions were still seen between PW-R and HC for three (IL-10, SIRT2 and FGF21) of the 10 proteins.ConclusionOur results contribute to unravelling potential immunopathological pathways shared between preschool wheeze and asthma.
28.	Klockmo, Carolina, 1976-, et al. (författare) I gränslandet mellan sfi och arbetslivsinriktade insatser 2015 Rapport (övrigt vetenskapligt/konstnärligt)abstract Att delta i arbetslivet fyller en viktig funktion för oss människor, inte enbart utifrån att vi får lön, utan det finns även ett antal socialpsykologiska bety-delser som de som står utanför arbetsmarknaden riskerar att gå miste om. Detta kan innebära en risk att utveckla ohälsa. Det är därför viktigt att ge människor, som av olika anledningar står utanför arbetsmarknaden, stöd för att etablera sig på arbetsmarknaden. Här kan flera aktörer komma att bli aktuella. I Sundsvalls kommun finns en verksamhet som heter Crea kompe-tens, vars målgrupp är utlandsfödda som har behov av att komma ut i prak-tisk verksamhet, dels för att förbättra sina språkkunskaper och dels för att lära sig ett nytt yrke. Syftet med rapporten var att studera Creas modell och resultatet bland deltagare som deltagit i verksamheten. Ytterligare ett syfte var att fånga erfarenheter som är viktiga för det framtida arbetet. För att få svar på dessa frågor har såväl gruppdiskussioner som enskilda intervjuer hållits med personal och arbetsgivare. I rapporten har även kvantitativt material använts i form av data som finns kring deltagarna. Resultatet visade att Crea utvecklat en metodik som syftade till att skapa förutsättningar för deltagaren att utveckla sina kunskaper i det svenska språket, få kunskap om de spelregler och kulturella normer som finns på svensk arbetsmarknad och att ge deltagarna en kortare yrkesutbildning inom något av områdena städ, restaurang, vaktmästeri, vård- och omsorg och handel. Resultatet visade att metodiken kan liknas vid Supported Employment metodiken. I Crea fanns strategier för att stödja den enskildes process som innebar att kartlägga och planera, erbjuda orienteringskurser, ge möjlighet att göra praktik på någon av yrkesplattformarna och stöd i att hitta en lämplig arbetsplats. Det var även möjligt att utreda arbetsförmåga genom arbetsträning. Det var möjligt att anpassa insatserna utifrån deltagarens behov. I Creas metodik var det viktigt att bygga broar mellan olika aktörer där handledarna fyllde en central funktion. De fungerade som stöd för både deltagaren, men även för arbets-givarna. Resultatet visade att av totalt cirka 195 deltagare så har drygt 130 har avslutat sin insats i maj 2015. Bland deltagarna var det 73 personer som haft någon form av anställning och 12 personer hade studerat. Creas verk-samhet är viktig då den vänder sig till en grupp som har stora behov av stöd för att integreras i arbetslivet. Det är dock viktigt med fortsatta diskussioner i synnerhet då Crea verkar "i gränslandet mellan sfi och arbetsmarknadsin-satser".
29.	Liu, Bojing, et al. (författare) Vagotomy and subsequent risk of inflammatory bowel disease : a nationwide register-based matched cohort study 2020 Ingår i: Alimentary Pharmacology and Therapeutics. - : John Wiley & Sons. - 0269-2813 .- 1365-2036. ; 51:11, s. 1022-1030 Tidskriftsartikel (refereegranskat)abstract Background: The vagus nerve provides essential parasympathetic innervation to the gastrointestinal system and is known to have anti-inflammatory properties.Aims: To explore the relationship between vagotomy and the risk of inflammatory bowel disease (IBD) and its major categories: Crohn's disease (CD) and ulcerative colitis (UC).Methods: A matched cohort comprising 15 637 patients undergoing vagotomy was identified through the Swedish Patient Register from 1964 to 2010. Each vagotomised patient was matched for birth year and gender with 40 nonvagotomised individuals on the date of vagotomy. We estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for IBD using flexible parametric models adjusted for matching variables, year of vagotomy, birth country, chronic obstructive pulmonary disease and comorbidity index.Results: We observed 119 (0.8%) patients with vagotomy developed IBD compared to 3377 (0.5%) IBD cases in nonvagotomised individuals. The crude incidence of IBD (per 1000 person-years) was 0.38 for vagotomised patients and 0.25 for nonvagotomised individuals. We observed a time-dependent elevated risk of IBD associated with vagotomy, for instance, the HR (95% CI) was 1.80 (1.40-2.31) at year 5 and 1.49 (1.14-1.96) at year 10 post-vagotomy. The association appeared to be stronger for truncal than selective vagotomy and limited to CD (HR was 3.63 [1.94-6.80] for truncal and 2.06 [1.49-2.84] for selective vagotomy) but not UC (1.36 [0.71-2.62] for truncal and 1.25 [0.95-1.63] for selective vagotomy).Conclusions: We found a positive association between vagotomy and later IBD, particularly for CD. The finding indirectly underlines the beneficial role of the vagal tone in IBD.
30.	Molin, Magnus, et al. (författare) Biomarkers of chronic airflow limitation and COPD identified by mass spectrometry 2024 Ingår i: ERJ Open Research. - : European Respiratory Society. - 2312-0541. ; 10 Tidskriftsartikel (refereegranskat)abstract RATIONALE: COPD affects 300 million people worldwide and is the third leading cause of death according to World Health Organization global health estimates. Early symptoms are subtle, and so COPD is often diagnosed at an advanced stage. Thus, there is an unmet need for biomarkers that can identify individuals at early stages of the disease before clinical symptoms have manifested. To date, few biomarkers are available for clinical diagnostic use in COPD.METHODS: We evaluated a panel of serum biomarkers related to inflammation and infection for their ability to discriminate between 77 subjects with chronic airflow limitation (CAL) and 142 subjects with COPD, versus 150 healthy subjects (divided into two control groups that were matched with regards to age, gender and smoking to CAL and COPD). Healthy subjects and CAL were from Burden of Obstructive Lung Disease (BOLD), a population-based study. CAL was defined by post-bronchodilatory forced expiratory volume in 1 s/forced vital capacity ratio <0.7 in the BOLD population. COPD subjects were from Tools for Identifying Exacerbations (TIE), a COPD patient cohort. Quantification of 100 biomarker candidates was done by liquid chromatography-tandem mass spectrometry.RESULTS: Several protein-derived peptides were upregulated in CAL, compared to controls; most notably peptides representing histidine-rich glycoprotein (HRG), α1-acid glycoprotein (AGP1), α1-antitrypsin (α1AT) and fibronectin. Out of these, HRG-, AGP1- and α1AT-specific peptides were also elevated in the COPD cohort.CONCLUSION: HRG, AGP1 and α1AT biomarkers distinguish subjects with CAL and COPD from healthy controls. HRG and AGP1 represent novel findings.
31.	Payandeh, Mostafa, et al. (författare) Influence of microstructure and heat treatment on thermal conductivity of rheocast and liquid die cast Al-6Si-2Cu-Zn alloy 2016 Ingår i: International Journal of Cast Metals Research. - : Informa UK Limited. - 1364-0461 .- 1743-1336. ; 29:4, s. 202-213 Tidskriftsartikel (refereegranskat)abstract Thermal conductivity of a rheocast component made from Stenal Rheo1 (Al-6Si-2Cu-Zn) alloy was investigated in as-cast, T5 and T6 conditions. The thermal conductivity measurement in different locations showed variation of this property throughout the rheocast component. The results of microstructural investigation revealed that the ratio of solute-lean α1-Al particles formed during slurry preparation to fine solute-rich α2-Al particles formed during secondary solidification had significant influence on thermal conductivity. The reduced amount of solutes in the α1-Al particles was determined as the root cause of higher thermal conductivity. A linear relation between the fraction of precipitates and the increase in thermal conductivity was obtained and silicon in solid solution is shown to have a dominant influence. As silicon was precipitated during the heat treatment, thermal conductivity increased. For an optimal combination of thermal and mechanical properties, it is therefore important to use an ageing temperature above the temperature of Si precipitation.
32.	Payandeh, Mostafa, 1981-, et al. (författare) Mechanical And Thermal Properties Of Rheocast Telecom Component Using Low Silicon Aluminium Alloy In As-Cast And Heat-Treated Conditions 2015 Ingår i: Light Metals 2015. - Hoboken, NJ : John Wiley & Sons. - 9781119082446 - 9781119093435 Konferensbidrag (refereegranskat)abstract The growing demand for increasingly more cost and energy effective electronics components is a challenge for the manufacturing industry. To achieve higher thermal conductivity in telecom components, an aluminum alloy with a composition of Al-2Si-0.8Cu-0.8Fe-0.3Mn was created for rheocasting. Yield strength and thermal conductivity of the material were investigated in the as cast, T5 and T6 heat-treated conditions. The results showed that in the as-cast condition thermal conductivity of 168 W/mK and yield strength of 67 MPa was achieved at room temperature. A T5 treatment at 200°C and 250°C increased thermal conductivity to 174 W/mK and 182 W/mK, respectively, while only a slight increase in yield strength was observed. Moreover, a T6 treatment resulted in similar thermal conductivity as the T5 treatment at 250°C with no significant improvement in yield strength. Therefore, the T5 treatment at 250°C was suggested as an optimum condition for the current alloy composition.
33.	Rudolph, Thiemo, et al. (författare) Ubiquitin carboxyl-terminal esterase L1 (UCHL1) S18Y polymorphism in patients with cataracts. 2011 Ingår i: Ophthalmic genetics. - : Informa UK Limited. - 1744-5094 .- 1381-6810. ; 32:2, s. 75-9 Tidskriftsartikel (refereegranskat)abstract Cataract is characterized by light-scattering protein aggregates. The ubiquitin-proteasome system has been proposed a role in proteolytic removal of these protein aggregates. Ubiquitin carboxyl-terminal esterase L1 (UCHL1) is a de-ubiquitinating enzyme with important functions in recycling of ubiquitin. A protective role of the p.S18Y polymorphism of the UCHL1 gene has been shown in Parkinson`s disease. The current study aimed to examine possible effects on cataract formation.
34.	Rydell, Niclas, et al. (författare) Serum Eosinophilic Cationic Protein Is a Reliable Biomarker for Childhood Asthma 2022 Ingår i: International Archives of Allergy and Immunology. - : S. Karger. - 1018-2438 .- 1423-0097. ; 183:7, s. 744-752 Tidskriftsartikel (refereegranskat)abstract Background: Eosinophilic cationic protein (ECP) is associated with airway inflammation and asthma. However, the clinical value of measuring ECP in childhood asthma is not fully known. We aimed to study the diagnostic performance of serum ECP and other common asthma biomarkers, individually and in combinations. Methods: In a cross-sectional study, 5-16-year-old children with current asthma (CA) (n = 37), transient asthma (TA) (n = 43), (previous history of wheezing/asthma), and healthy children (HC) (n = 86) were investigated for ECP, blood eosinophil count (B-Eos), fractional exhaled nitric oxide (FeNO), and lung function, i.e., spirometry (forced expiratory volume during the first second [FEV1]/forced vital capacity [FVC] ratio). Results: Both ECP and B-Eos were higher in CA compared to TA (p < 0.01) and HC (p < 0.0001). ECP and B-Eos were also higher in TA compared to HC (p < 0.05 and p < 0.001, respectively). FeNO was higher in CA (p < 0.0001) and TA (p < 0.01) compared to HC but similar between the asthma groups. The FEV1/FVC ratio was lower in CA compared to TA and HC (both p < 0.01) but similar between TA and HC. The best diagnostic performance regarding CA was found for ECP and B-Eos with receiver operating characteristics area under curve (AUC) of 0.801 and 0.810, respectively. The optimal cutoff for ECP (29 mu g/L) yielded a sensitivity and specificity of 70.3% and 81.4%. The corresponding AUCs for FeNO and FEV1/FVC were 0.732 and 0.670, respectively. ECP and B-Eos showed the highest AUCs (0.669 and 0.673) for differentiation between CA and TA. Combining ECP with FeNO and FEV1/FVC increased the odds ratio (OR) for having CA from OR 3.97-10.3 for the single biomarkers to OR 20.2 (95% confidence interval: 5.76-68.6). Conclusion: Our results show that serum ECP is a reliable biomarker in the diagnosis of childhood asthma, with additional value in combination with FeNO and FEV1/FVC, and that ECP can be an alternative to B-Eos.
35.	Sjölander, Andreas, 1983- (författare) Analyses of shotcrete stress states due to varying lining thickness and irregular rock surfaces 2017 Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract Shotcrete is sprayed concrete applied pneumatically under high pressure and was invented in the beginning of the 1900's. This new technique decreased the construction time and since steel fibres were introduced in the shotcrete during the 1970's, shotcrete has been the primary support method for tunnels.Tunnels excavated with the drill and blast method creates a highly irregular rock surface which results in a shotcrete lining with varying thickness. The structural behaviour as well as the loads acting on the shotcrete lining depends on the interaction between the shotcrete, rock and rock bolts. There are several parameters influencing this interaction, e.g. bond strength, the stiffness of the rock and thickness of the shotcrete. All of these parameters are difficult to predict accurately which makes the structural design of the lining to a complex problem.This thesis present the first part of a research project with the long-term goal to improve the understanding of the structural behaviour of the shotcrete lining. To achieve this, numerical modelling have been used to study the build up of stresses and cracking of shotcrete when subjected to restrained loading caused by e.g. temperature differences and drying shrinkage. The response in the lining when subjected to a gravity load from a block has also been studied. The model is capable of describing the non-linear deformation behaviour of both plain and fibre reinforced shotcrete and uses presented in situ variations in thickness to more accurately account for the effects of expected variations in thickness. The thesis discuss and demonstrate the effect of important loads that acts on the shotcrete lining and how the irregular geometry of the rock surface in combination with the varying thickness of the shotcrete affect the development of stresses in the lining. It is also discussed how a full or partial bond failure affect the structural capacity of a shotcrete lining.
36.	Sjölander, Andreas, 1983-, et al. (författare) Analysis of the interaction between rock and shotcrete for tunnel support 2017 Ingår i: XXIII Nordic Concrete Research Meeting. Konferensbidrag (refereegranskat)abstract The first part of a project aiming at increase the knowledge and understanding of how shotcrete (sprayed concrete) in interaction with rock could better be modelled is presented. The study focus on how an irregular thickness of shotcrete will affect its structural capacity. Examples show that continuously bonded shotcrete have an ability to redistribute local stresses while partly de-bonding leads to localized, wide cracks. One goal is to obtain a better understanding for how and why cracking and bond failure is initiated. The results obtained so far are here briefly summarized and commented, also showing some examples of results.
37.	Sjölander, Anders (författare) Att reglera eller inte reglera : en undersökning av sparbanksfrågan i riksdagen 1882-1939 2000 Rapport (övrigt vetenskapligt/konstnärligt)
38.	Sjölander, Anders (författare) Att reglera eller inte reglera - en undersökning av sparbanksfrågan i riksdagen 1882-1939 2000 Rapport (övrigt vetenskapligt/konstnärligt)
39.	Sjölander, Andreas, 1983-, et al. (författare) Data from structural testing of sprayed and cast shotcrete reinforced with fibres of steel, basalt and synthetic material 2022 Annan publikationabstract In this dataset, data from experimental testing of fibre-reinforced shotcrete is presented. The dataset contains five different fibres made of steel (Dramix 3D, Dramix 4D and Dramix5D), synthetic (BarChip R54) and basalt (MiniBar). Preparation of specimens and testing were performed by Vattenfall R&D in Älvkarleby, Sweden. This first version of the dataset contains the results for shotcrete specimens prepared through casting. The same shotcrete mix was used for all specimens, and three different dosages were used for each of the fibres except for Dramix 5D, for which only two dosages were tested. The dataset contains the shotcrete mix and standard output for the test of compressive strength according to EN 12390-3, residual flexural strength according to EN 14488-3 and energy absorption according to ASTM C1550. This dataset can be used to study how the structural toughness of fibre-reinforced shotcrete is affected by the dosage of fibre. Moreover, the data can be used to compare the structural performance of fibres of different materials. The data also provide a foundation to select a reasonable dosage of fibres to fulfil the structural requirements put on shotcrete in the design phase.
40.	Sjölander, Anders, 1957- (författare) Design, production and characterization of synthetic immunogens : application on Plasmodium falciparum malaria antigens 1991 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract The development of synthetic subunit vaccines is presently one of the major strategies to construct vaccines against infectious diseases. Such vaccines are based on isolated and characterized immunogens and should include appropriate B- and T-cell epitopes. The construction of synthetic vaccines is dependent on the accessibility of techniques for efficient production of the immunogens and the possibility to combine several immunogens and safe and potent adjuvant/ delivery systems in the same vaccine formulation. The present thesis describes methods for the design, production and immunological characterization of immunogens based on the Plasmodium falciparum malaria blood stage antigens Pf 155/RES A and Clustered-Asparagine- Rich-Protein (CARP).Genetic fusion systems based on the IgG-binding domains of staphylococcal protein A and the serum albumin binding region of streptococcal protein G were developed for the polymerization, assembly and expression of genes encoding epitope-carrying peptides and the subsequent affinity purification of the produced fusion proteins by a one-step procedure. Immunogens produced in this way were immunogenic in various animal models after administration in Freund's adjuvant and induced antibodies which reacted with the malaria sequence used for immunization as well as with the corresponding intact protein. Furthermore, these antibodies were efficient inhibitors of merozoite invasion of erythrocytes in vitro. The antibody responses were sustained over long time periods, could be efficiently boosted and were specific for Pfl55/RESA as well as the sequence used for immunization.Since Freund's adjuvant is not suitable for use in humans, the immunopotentiating capacity of several other adjuvant/delivery systems was investigated. Of these, only immunostimulating complexes (ISCOMs) induced antibody levels comparable to those obtained with Freund's adjuvant. ISCOMs are spherical particles composed by the glycoside adjuvant Quil A, cholesterol and phospholipids in which antigens are presented in a multimeric form. ISCOM-based immunogens were prepared by direct incorporation or by conjugation of fusion proteins to pre-formed influenza vims ISCOMs. Immunization with ISCOMs prepared in this way resulted in strong antibody responses to all polypeptide components of the particles and these antibodies recognized the corresponding intact proteins. The antibody responses induced by the ISCOMs were efficiently boosted, indicating the induction of immunological memory including memory specific for the malariaderived sequences. The efficient boosting of the antibody responses to the malaria sequences suggests that possible competitive or suppressive effects of the additional components of the ISCOM preparations in general were weak or absent. Taken together, these results imply that incorporation or conjugation of fusion proteins to ISCOMs may form a suitable basis for the construction of multivalent synthetic subunit vaccines.The immunogenicity in inbred mice of synthetic immunogens has been shown to be influenced by genetic restriction. Strong B- and T-cell responses in mice to fusion proteins containing large numbers of Pf 155/RES A repeat sequences were linked to expression of the MHC class II I-Ak allele. While a certain cross-reactivity between the different Pf 155/RES A repeat sequences was demonstrated for the T-cells that were stimulated by the fusion proteins, the corresponding antibody responses were specific for the repeat sequences used for immunization. These results indicate that the T-cells which were induced by immunization with the different fusion proteins and the corresponding B-cells had separate major specificities.
41.	Sjölander, Andreas, Ph.D, 1983-, et al. (författare) Effective use of fibres of various types and material for shotcrete in rock support for tunnels. 2023 Ingår i: ITA‐AITES World Tunnel Congress. - London : Taylor & Francis Group. Konferensbidrag (refereegranskat)abstract Large volumes of steel fibre reinforced shotcrete (sprayed concrete) and steel bolts are commonly used to support tunnels in hard rock. This generates a high CO2-footprint which must be reduced in order to decelerate the continuously increasing average temperature worldwide caused by the emissions of greenhouse gases. Thus, alternative design methods and the possibility to use other materials than steel are currently investigated. Work is ongoing on testing the load-bearing capacity of shotcrete reinforced with fibres of steel, basalt and synthetic materials. This also includes a comparison between tests using Round Determinate Panels (RDP) and four-point bending of beams. Moreover, the practical use of RDP testing as a quality control methodology is also investigated in situ. Here, the goal is to identify several shotcrete mixes suitable for use in tunnelling so that the right material and fibre volume can be used in the right place.
42.	Sjölander, Andreas, Ph.D, 1983-, et al. (författare) Effective use of fibres of various types and material for shotcrete in rock support for tunnels 2023 Ingår i: Expanding Underground - Knowledge and Passion to Make a Positive Impact on the World- Proceedings of the ITA-AITES World Tunnel Congress, WTC 2023. - : Informa UK Limited. ; , s. 932-939 Konferensbidrag (refereegranskat)abstract Large volumes of steel fibre reinforced shotcrete (sprayed concrete) and steel bolts are commonly used to support tunnels in hard rock. This generates a high CO2-footprint which must be reduced in order to decelerate the continuously increasing average temperature worldwide caused by the emissions of greenhouse gases. Thus, alternative design methods and the possibility to use other materials than steel are currently investigated. Work is ongoing on testing the load-bearing capacity of shotcrete reinforced with fibres of steel, basalt and synthetic materials. This also includes a comparison between tests using Round Determinate Panels (RDP) and four-point bending of beams. Moreover, the practical use of RDP testing as a quality control methodology is also investigated in situ. Here, the goal is to identify several shotcrete mixes suitable for use in tunnelling so that the right material and fibre volume can be used in the right place.
43.	Sjölander, Andreas, Ph.D, 1983-, et al. (författare) Failure Mechanisms of Fibre Reinforced Shotcrete : Numerical Simulations Considering Local Variations in Thickness and Bond Strength 2022 Ingår i: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 2545-2819. ; 67:2, s. 51-64 Tidskriftsartikel (refereegranskat)abstract Fibre-reinforced shotcrete is the most common support method for hard rock tunnels in the Nordic countries. The design of shotcrete is often based on empirical methods or simplified analytical equations, which neglect variations in mechanical properties and shotcrete thickness. Data collected from the field shows that significant variations in shotcrete thickness and bond strength should be expected during tunnel construction. However, how this affects the structural behaviour and capacity of the shotcrete lining is unknown. Moreover, the design philosophy for shotcrete assumes that the primary failure modes of shotcrete, i.e. bond and flexural failure, can be treated separately. This was derived based on observations of experiments in a laboratory environment. Therefore, the focus of a finalized doctoral project was to develop a numerical framework to simulate the structural behaviour of fibre-reinforced shotcrete in interaction with hard rock and rock bolts. The effect of variations in shotcrete thickness and bond strength was studied through numerical simulations to increase the understanding of its effect on the failure load of the lining. The results indicate that the most important parameter is the mean value of the shotcrete thickness and bond strength around a narrow perimeter of the block.
44.	Sjölander, Andreas, 1983-, et al. (författare) In-Situ and Laboratory Investigation on Leaching and Effects of Early Curing of Shotcrete 2019 Ingår i: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 61:2, s. 23-37 Tidskriftsartikel (refereegranskat)abstract During the construction of a rock tunnel in Stockholm, several sections with leaching shotcrete (sprayed concrete) were found one year after the spraying was completed. An investigation was therefore conducted, and its results are presented in this paper. The amount of leaching after such a short time indicated that a one-sided water pressure existed in combination with a permeable shotcrete. The reason for the water pressure was likely a partly unsuccessful grouting that created sections with leaking water. The permeable shotcrete could be a combined result of insufficient curing and the use of accelerators, and the effect of in-situ curing was therefore investigated. A total of six slabs were sprayed and cured under different conditions in the tunnel. Test results according to standards indicated that curing has no significant effect on the development of mechanical strength or water penetration through the shotcrete. However, this is believed to be a result of the test method rather than the non-existing effect of curing. Lastly, some modifications to the test standard were proposed for future studies of in-situ curing.
45.	Sjölander, Andreas, et al. (författare) Investigation of non-linear drying shrinkage for end-restrained shotcrete of varying thickness 2018 Ingår i: Magazine of Concrete Research. - : ICE Publishing. - 0024-9831 .- 1751-763X. ; 70:6, s. 271-279 Tidskriftsartikel (refereegranskat)abstract Tunnels in hard, jointed rock are commonly reinforced with shotcrete (sprayed concrete) applied directly on the irregular rock surface. The thickness for such linings can be as small as 50 mm, which result in a fast drying. The resulting shrinkage of the restrained lining is a well-known phenomenon, which leads to cracking. The installation of drainage systems also results in an end-restrained shotcrete lining that is more prone to shrinkage cracking. The drying process is a complex problem that depends on multiple factors such as cement content, porosity and ambient air conditions (i.e. temperature, relative humidity and wind speed). Two numerical models capable of capturing the structural effects of drying shrinkage were compared in this study. It was found that inclusion of non-linear drying shrinkage is important for accurately describing crack initiation in an end-restrained shotcrete slab. The best fit to the experimental data was obtained when the rate of drying was described as a non-linear decreasing function.
46.	Sjölander, Andreas, 1983-, et al. (författare) Investigation of non-linear drying shrinkage for end-restrained shotcrete with varying thickness Ingår i: Magazine of Concrete Research. - 0024-9831 .- 1751-763X. Tidskriftsartikel (refereegranskat)abstract Tunnels in hard, jointed rock is commonly reinforced with shotcrete (sprayed concrete) applied directly on the irregular rock surface. The thickness for such lining can be as low as 50 mm which result in a fast drying. The resulting shrinkage of the restrained lining is a well known phenomena that causes cracking. Installation of some drainage system also results in an end-restrained shotcrete lining which is more prone to shrinkage cracking. The drying process is a complex problem that depends on multiple factors such as cement content, porosity and conditions of ambient air, i.e. temperature, relative humidity and wind speed. In this paper, two numerical models capable of capturing the structural effects of drying shrinkage was compared. Results shows that inclusion of non-linear drying shrinkage is important to accurately describe crack initiation in a end-restrained shotcrete slab. Best fit to experimental data was obtained when the rate of drying was described as a non-linear decreasing function.
47.	Sjölander, Andreas, 1983-, et al. (författare) Klimatsmart fiberarmerad sprutbetong för trafiktunnlar 2022 Ingår i: Bygg och Teknik. - Stockholm. - 0281-658X .- 2002-8350. ; 114:6, s. 28-30 Tidskriftsartikel (populärvet., debatt m.m.)abstract Världen står inför en enorm utmaning där utsläppen av växthusgaser måste minskas för att bromsa den ständigt ökande globala medeltemperaturen. Samtidigt har en lång urbaniseringstrend lett till att transportinfrastrukturen i många tätbefolkade städer måste byggas ut för att bibehålla ett fungerande transportnät. I många fall är tunnlar det mest fördelaktiga alternativet eftersom de inte stör den befintliga stadsbilden. För att minska klimatpåverkan från byggandet av nya tunnlar har Trafikverket initierat ett forskningsprojekt som ska undersöka potentialen för alternativa fibrer och detta drivs av avdelningen för Betongbyggnad på KTH.
48.	Sjölander, Andreas, 1983-, et al. (författare) Modelling aspects to predict failure of a bolt-anchored fibre reinforced shotcrete lining 2018 Ingår i: 8th International Symposium on Sprayed Concrete. - Trondheim. - 9788282080606 ; , s. 278-292 Konferensbidrag (refereegranskat)abstract Tunnels in hard and jointed rock are normally excavated with an arch shape to enable the rock to carry itself. The arch effect depends on the stability of individual blocks and too high or too low horizontal stresses could cause blocks to be pushed out or to fall down. To prevent this, systematic rock bolting in combination with fibre reinforced sprayed concrete (FRSC) is commonly used to support the rock. To understand the failure mechanism of the lining when subjected to the load from one block is therefore important for the design. In this paper, the three main failure mechanisms for a rock support shotcrete lining has been identified as failure in the fibre reinforced concrete, bond failure between shotcrete and rock or failure of rock bolts. For each of the failure modes, a short review of numerical methods is presented followed by a selection of a preferred modelling approach. The selected methods are then verified against experimental results from the literature. The selected methods all shows good agreements with tests and demonstrates the ability to simulate each failure mode one by one.
49.	Sjölander, Andreas, 1983-, et al. (författare) Numerical simulations of restrained shrinkage cracking in glass fibre reinforced shotcrete slabs 2017 Ingår i: Advances in Civil Engineering / Hindawi. - : Hindawi Publishing Corporation. - 1687-8086 .- 1687-8094. ; :8987626 Tidskriftsartikel (refereegranskat)abstract Modern tunnels in hard rock are usually constructed by drill and blast with the rock reinforced by shotcrete (sprayed concrete) in combination with rock bolts. The irregular rock surface and the projection method of shotcrete leads to a tunnel lining of varying thickness with unevenly distributed stresses that affect the risk of cracking during shrinkage of the young and hardening material. Depending on water conditions, shotcrete is either sprayed directly onto the rock surface or over a drainage system, creating a fully restrained or an end-restrained structural system. In this paper, a method for non-linear numerical simulations has been demonstrated, for the study of differences in stress build up and cracking behaviour of restrained shotcrete slabs subjected to shrinkage. Special focus was given to the effects of the irregular shape and varying thickness of the shotcrete. The effects of glass fibre reinforcement and bond were implemented in the study by changing the fracture energy in bending and in the interaction between shotcrete and the substrate. The study verifies that an end-restrained shotcrete slab is prone to shrinkage induced cracking, and shows the importance of a continuous bond to avoid wide shrinkage cracks when shotcrete is sprayed directly onto the rock.
50.	Sjölander, Andreas, 1983-, et al. (författare) On failure probability in thin irregular shotcrete shells 2017 Ingår i: Proceedings of the World Tunnel Congress 2017. Konferensbidrag (refereegranskat)abstract Tunnels through hard jointed rock are commonly reinforced with a combination of fibre reinforced shotcrete (sprayed concrete), FRS, and rock bolts. The design of such reinforcement is a complex task. First, the interaction between rock bolts, FRS and rock should be considered. Secondly, a natural variation in important parameters such as thickness of the shotcrete, fracture energy, and bond strength between shotcrete and rock exists. In this paper, a numerical framework for non-linear analyses of FRS suitable for Monte Carlo simulations is presented. As a case study, a 2D FE-model of a bolted shotcrete lining subjected to load from a pushing block was used to perform a sensitivity analysis for the variation in thickness. Results indicate that an irregular shotcrete thickness highly affects the failure load but has a smaller impact on ductility.

Skapa referenser, mejla, bekava och länka

Länka till träfflistan

Träfflista för sökning "WFRF:(Sjölander Anders) "

Avgränsa träffmängd

År