Chalmers Open Digital Repository

Welcome to Chalmers Open Digital Repository!

Here you can find:

  • Student theses and papers
  • Digital special collections, such as Chalmers modellkammare
  • Selected project reports

Research publications, reports and dissertations can be found in research.chalmers.se

Communities in Chalmers ODR

Select a community to browse its collections.

Now showing 1 - 2 of 2

Recent Submissions

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    On the Relationship of Arctic Polynyas and Atmospheric Rivers. Analyzing Arctic polynya and atmospheric river activity during winter seasons between 1979 and 2019
    (2026) Engelsson, Judit; Strandvik, Martine; Winnes, Tyra
    Atmospheric rivers [ARs] are narrow and long regions characterized by unusually high moisture transport. ARs have over the last decades experienced a poleward shift and are because of this becoming more important to study in the higher latitudes. Arctic polynyas, openings in the sea ice cover, have simultaneously increased in frequency. However, the effect of ARs on arctic polynyas have not been sufficiently studied. In this study, we investigate the potential relationship between ARs and Arctic polynyas. Using a public dataset based on satellite data and one AR-catalogue from the ARTMIP project, we retrieved polynya and AR activity for the winter seasons between 1979 and 2019. Initially, an Arctic-wide analysis was made. We analyzed the general characteristics of ARs and polynyas independent of their location. Then we examined the relationship between ARs and polynya opening events, here defined as the polynya variable changing from closed to open for any grid cell. Subsequently, we identified nine regions with high polynya activity and conducted a similar analysis for these individually. Our results show a positive correlation (r ≈ 0.49) between AR frequency and polynya opening events across the Arctic. Over a period of four days before the opening, ARs are present during approximately 36% of polynya opening events. This is a substantial increase compared to the baseline AR occurrence, which is almost 7%. The relationship between ARs and polynya openings is strongest one day prior to the opening event. The regional analysis reveals high variability, with five out of nine regions showing positive corre lations between AR frequency and polynya opening events, while the four remaining exhibit weak or negative correlations. The highest correlation is observed in Franz Josef Land, which has a high amount of both polynya openings and ARs. Furthermore, the regions Kara Sea, Svalbard and Chukchi Sea show a large increase in AR activity over polynya opening locations during the upcoming days of the opening event. These findings suggest that ARs contribute to the triggering or enhancement of polynya openings. Further investigation is needed, as investigating ARs’ effect on polynya openings as opposed to expansion of already existing polynyas, to better understand the dynamics of Arctic polynyas and AR activity.
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    Effective area in restrained reinforced concrete: Finite Element Analysis in relation to models presented in Eurocode 2
    (2026) Josefsson, Amelie; Svensk, Alva
    Cracking of concrete is a well-known phenomenon in most concrete structures, due to the low tensile strength of the material. In a reinforced concrete element, cracking initiates a redistribution of stresses from the concrete to the reinforcement. Depending on the thickness of the element, redistribution of stresses in the surroundings of a crack may create an area of concentrated stresses, an effective area, where the next crack will be created. Cracking, though, does not imply failure, as well-designed elements allow for redistribution. Eurocode is a commonly used framework that is used as a basis for structural design, and therefore the presented models must be accurate and applicable to all elements, striving for well-designed and material-efficient structures. In the second generation of Eurocode, more specifically, SS-EN 1992-1-1, a model for the effective area in concrete structures is provided. The way of modelling this slightly changed between the old version from 2005 and the newer one published in 2023. Further on, the definition of the effective area in Eurocode is not primarily derived being applicable to restrained elements. This thesis investigates whether these models apply to restrained elements. Theory related to cracking in restrained reinforced concrete was investigated. The models provided in the two versions were studied and compared. Evaluation of the effective area was done by non-linear Finite Element Modelling in the software DIANA, using a linear concrete material and a non-linear bond-slip interface between concrete and reinforcement. The stress distribution for a restrained reinforced concrete element with varying geometry was used for the evaluation of the effective area. Analytical calculations based on the models in the second generation of Eurocode were also performed, and the results were compared with the numerical results. The final results obtained from Finite Element Analysis did not correlate with the models for effective area. However, the concept of effective areas, i.e stress concentrations in the concrete adjacent to reinforcement, was clearly observed, and a maximum tensile stress section was obtained, in line with the theory. The overall conclusion is that the existing models do not apply to restrained elements and that an improved model is required. Due to a lack of correlation in results, further investigation of the subject is needed.
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    How much H2 in 2030 – where, to whom and with what probability? Quantifying hydrogen production in Sweden under different scenarios
    (2026) Björstrand, Ebba; Jacobsson, Tova
    Hydrogen is widely regarded as a key enabler of decarbonization in hard-to-abate sectors, yet its market development remains highly uncertain. This thesis investigates the potential scale and conditions for green hydrogen production in Sweden toward 2030 by combining project mapping, stakeholder interviews, and scenariobased modeling. The study aims to quantify future hydrogen production, identify key demand sectors, and analyze the main drivers and barriers influencing market development. The results indicate that potential production outcomes vary significantly depending on realization conditions. While an upper-bound estimate suggests a possible production capacity of approximately 660,000 tonnes of hydrogen per year, the most probable outcome is substantially lower under current conditions. The analysis identifies a limited number of large-scale industrial projects as system anchors that largely determine overall production volumes. A total of 43 hydrogen production projects were assessed using a probabilistic framework based on four core factors: project status, electricity bidding zone, public funding, and sector readiness. These were evaluated under three socio-economic scenarios (SSP1, SSP2, SSP3), complemented by Monte Carlo simulations to capture uncertainty in project realization. Key barriers include high production costs, uncertain demand, infrastructure limitations, and persistent coordination challenges between producers and consumers. The study concludes that hydrogen market development in Sweden is highly interdependent, relying on progress across both the hydrogen value chain and the regulatory landscape, and remains embedded within a broader global system. Achieving large-scale deployment therefore requires coordinated action, including strengthened and coherent policy frameworks, demand-side support mechanisms, and improved alignment between supply and demand.
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