| 1. |
- Jamalzadeh, Saeed, et al.
(författare)
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Weaponized disinformation spread and its impact on multi-commodity critical infrastructure networks
- 2024
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Ingår i: Reliability Engineering and System Safety. - 0951-8320. ; 243
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Tidskriftsartikel (refereegranskat)abstract
- The well-publicized disinformation campaigns surrounding recent elections, pandemic vaccination adoption, as well as supply-chain disruptions and shortages have made historical problems of disinformation more apparent. When disinformation targets transportation infrastructure, supply chains can be disrupted, resulting in commodities shortages such as food and fuel, consequently jeopardizing the health and safety of communities. This research proposes an integrated epidemiological-optimization model that quantifies the impacts of weaponized disinformation on infrastructure networks that transport multiple commodities. The model aims to minimize the overall weighted shortage of commodities caused by different disinformation spread rates. Results show that disinformation weaponized against transportation infrastructure, potentially targeting a particular geographical region or a particular commodity, can have wide-ranging impacts across different commodities. The proposed model is applied to the multi-commodity Swedish railway network carrying 14 different categories of commodities over 1360 supply and demand nodes.
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| 2. |
- Kuttler, Emma, et al.
(författare)
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Protection-interdiction-restoration for resilient multi-commodity networks
- 2024
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Ingår i: Reliability Engineering and System Safety. - 0951-8320. ; 242
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Tidskriftsartikel (refereegranskat)abstract
- Interdependent critical infrastructure systems represent substantial financial investments and are vital to maintain a fundamental level of social and economic well-being, making them attractive targets for malevolent actors. Many of these infrastructure systems carry multiple products, each with unique needs and importance to different stakeholders. This work extends a tri-level protection-interdiction-restoration model from a single commodity to multiple commodities, solving the model with an integration of Benders’ decomposition and set covering decomposition. We propose a method to limit unmet weighted demand across commodities, considering unique interdependencies between network components and commodity-specific capacity requirements. An optimal solution is found iteratively by alternately fixing protection and interdiction variables. This work is illustrated with a case study of interdependent Swedish power and multi-commodity railway systems. Results demonstrate the convergent behavior of the master and subproblems, the value of network hardening, and the non-uniform network recovery trajectory. For the case study, the railway system was more vulnerable to disruption than the power system, making it a more attractive target for both protection and interdiction. The components that were commonly selected as part of a protection or interdiction plan were generally the ones with the greatest demand for iron ore, a highly critical commodity.
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| 3. |
- Lindström Månefjord, Josefin, et al.
(författare)
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Critical flows throughout the Covid-19 pandemic – A longitudinal study on interdependencies and resilience in a Swedish context
- 2024
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Ingår i: International Journal of Disaster Risk Reduction. - 2212-4209. ; 103
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Tidskriftsartikel (refereegranskat)abstract
- Modern societies rely on critical flows of essential goods and services to ensure societal safety. The covid-19 pandemic highlighted the importance of upholding critical flows during a crisis. This comprehensive study provides novel insights into interdependencies and resilience of critical flows by carrying out a longitudinal and holistic study throughout the pandemic in Sweden of four sectors: transport, energy, info-com, and food. News articles concerning actual and potential impacts, interdependencies, and statements of preparedness and resilience on critical flows were used as the primary material. 300 different sources generated 8076 news and opinion articles. 194 articles were included, from which 411 flow incidents, 298 flow interdependencies, and 191 accounts on flow resilience were analyzed. Authority reports were used as secondary material for validating and contrasting the primary findings. Our findings outline the nature and scale of critical flow disruptions and their complex interdependencies during the entirety of the pandemic. Several conclusions are drawn. The main drivers of disruptions were due to cascading effects across critical flows, followed by restrictions to contain the virus. Despite fear and speculation of potential flow disruptions and deemed low preparedness, the studied sectors coped well with the pandemic as no widespread societal consequences were observed – suggesting high resilience. The discrepancies between potential and actual disruptions and limited accounts of interdependencies in the material reveal a limited collective understanding of flow disruptions and their intricate interdependencies. This underscores the importance of a holistic understanding of critical flow complexity and improved cross-sectoral governance of flow-related risks.
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| 4. |
- Nasr, Amro, et al.
(författare)
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The need for nonuniform risk acceptability across climate change scenarios
- 2024
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Ingår i: Risk Analysis. - 0272-4332.
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Tidskriftsartikel (refereegranskat)abstract
- Climate change risk assessment studies focus on identifying and analyzing different risks considering several climate change scenarios and on evaluating the cost-effectiveness of different adaptation measures. However, risk acceptability is often not reflected on in the context of climate change risk studies. Noting that the different climate change scenarios depict drastically contrasting images of the future in terms of population growth, economic development, and changes to life expectancy, this article uses risk acceptance criteria that are based on socioeconomic considerations to highlight the need for nonuniform risk acceptability across climate change scenarios. For this purpose, the optimum implied cost of averting a fatality derived based on the life quality index concept and the value of a quality-adjusted life year derived based on the time principle of acceptable life risk are assessed in three different climate change scenarios for Sweden. Additionally, an illustrative example that assesses the acceptable probability of failure of a steel rod under axial tension in the different climate change scenarios is presented. It is shown that risk acceptance criteria can vary considerably across the different climate change scenarios (e.g., more than 190% variation in the acceptable probability of failure for Sweden in the considered example). This article demonstrates that the ability of societies to afford risk-reducing measures may vary considerably across the different climate change scenarios. Hence, it can be concluded that (1) in the context of climate change risk assessments, risk acceptance criteria need to be developed to account for the different climate change scenarios, and (2) these criteria may vary considerably across the different climate change scenarios. Finally, relevant challenges and research needs are also provided.
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| 5. |
- Arvidsson, Björn, et al.
(författare)
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A methodological approach for mapping and analysing cascading effects of flooding events
- 2023
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Ingår i: International Journal of River Basin Management. - : Informa UK Limited. - 1814-2060 .- 1571-5124. ; 21:4, s. 659-671
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Tidskriftsartikel (refereegranskat)abstract
- Current local or regional flood risk assessments, as required by the EU flood risk directive, rarely account for cascading effects due to interdependencies between critical infrastructures. However, it is essential to consider these effects, as they may severely impact areas outside the immediate flood risk area. The main purpose is to present and problematize a method (AB-CEM) for mapping and analysing cascading effects due to floods, aiming at also being relevant for other spatially widespread hazards. The method development and the pilot study, in Sweden, reveal that there is a prominent practical need for methods for mapping and analysing critical infrastructure interdependencies and cascading effects. Another key finding is that the method process and its results can serve as an important basis for decision-making about proactive and reactive efforts related to geographically extensive hazards. We further conclude that there is a recurring problem regarding sensitive and secret data. More specifically, the conflicting interests of information availability and information security concerning critical infrastructures, which needs to be resolved at the national level and communicated through clear guidelines. The method is a much-needed step towards accounting for cascading effects of floods in practice.
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| 6. |
- Benter, Sandra, et al.
(författare)
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Geometric control of diffusing elements on InAs semiconductor surfaces via metal contacts
- 2023
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Ingår i: Nature Communications. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Local geometric control of basic synthesis parameters, such as elemental composition, is important for bottom-up synthesis and top-down device definition on-chip but remains a significant challenge. Here, we propose to use lithographically defined metal stacks for regulating the surface concentrations of freely diffusing synthesis elements on compound semiconductors. This is demonstrated by geometric control of Indium droplet formation on Indium Arsenide surfaces, an important consequence of incongruent evaporation. Lithographic defined Aluminium/Palladium metal patterns induce well-defined droplet-free zones during annealing up to 600 °C, while the metal patterns retain their lateral geometry. Compositional and structural analysis is performed, as well as theoretical modelling. The Pd acts as a sink for free In atoms, lowering their surface concentration locally and inhibiting droplet formation. Al acts as a diffusion barrier altering Pd’s efficiency. The behaviour depends only on a few basic assumptions and should be applicable to lithography-epitaxial manufacturing processes of compound semiconductors in general.
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| 7. |
- Bermeo, Marie, et al.
(författare)
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Branched-gallium phosphide nanowires seeded by palladium nanoparticles
- 2023
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Ingår i: Nanotechnology. - 0957-4484. ; 34:39
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Tidskriftsartikel (refereegranskat)abstract
- Palladium nanoparticles were produced by a chemical reagent-free and versatile method called spark ablation with control over particle size and density. These nanoparticles were used as catalytic seed particles for gallium phosphide nanowire growth by metalorganic vapour-phase epitaxy. Controlled growth of GaP nanowires using significantly small Pd nanoparticles between 10 and 40 nm diameter was achieved by varying several growth parameters. Low V/III ratios below 2.0 promote higher Ga incorporation into the Pd nanoparticles. Moderate growth temperatures under 600 °C avoid kinking and undesirable GaP surface growth. In addition, a second batch of palladium nanoparticles of concentration up to 1000 particles μm−2 was deposited onto the GaP nanowires. Subsequently, three-dimensional nanostructures evolved, with branches growing along the surface of the GaP nanowires. The GaP nanowires revealed a zinc blende structure with multiple twinning and a PdGa phase at the tip of the nanowires and branches.
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| 8. |
- Escobar Steinvall, Simon, et al.
(författare)
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Visualizing the Mechanism Switching in High-Temperature Au-Catalyzed InAs Nanowire Growth
- 2023
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Ingår i: Crystal Growth and Design. - 1528-7483. ; 23:9, s. 6228-6232
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Tidskriftsartikel (refereegranskat)abstract
- We use environmental transmission electron microscopy to observe in situ the switch from an axial vapor-liquid-solid (VLS) growth mechanism in Au-catalyzed InAs nanowires toward a radial vapor-solid (VS) one, dominated by layers nucleating at the triple-phase line. At elevated temperatures, in addition to high V/III ratios, the affinity for In in the Au catalyst will be greater than that of In in InAs, which in turn reduces the driving force and probability for nucleation at the liquid-solid interface. Consequently, with increased temperature, the catalyst particle stops acting as a sink for incoming material and the decomposition of precursors away from the catalyst increases, making radial vapor-solid growth the dominating growth mechanism. It is further observed that the growth proceeds through multistep propagation rather than a layer-by-layer propagation under these conditions.
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| 9. |
- Johansson, Jonas, et al.
(författare)
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Fritidshemspersonals tal om barns fysiska aktivitet – samhällelig påverkan och möjliga implikationer
- 2023
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Ingår i: Education & Learning. - Falun : Dalarna University. - 2001-4554. ; 17:1, s. 45-63
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this paper is to shed light on how teachers’ talk about children’s physical activity in school-age educare can be seen as part of comprehensive social discourses concerning education and physical activity. Focus-group interviews with a discourse-analytic approach have been carried out with staff from two municipal school-age educare in Sweden. The transcriptions was analyzed with inspiration from critical discourse analyze which is the theoretical standpoint. In the result the discourses of risk, shortage, activity, complement and joy of movement are the most prominent. In analysis these discourses are seen as inter-discursively influenced by the public health discourse wherein concepts as activity rate, discipline, joy of movement and organization are central. These discourses, concepts and possible implications for school-age educare are discussed. It is also argued that a social pedagogical discourse of care with focus on children’s relation making and conflict management seems to be manifest within Swedish school-age educare.
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| 10. |
- Johansson, Jonas
(författare)
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Heteroepitaxial growth modes revisited
- 2023
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Ingår i: CrystEngComm. - 1466-8033. ; 25:48, s. 6671-6676
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Tidskriftsartikel (refereegranskat)abstract
- It is well known that the outcome of a thin film deposition experiment on a foreign substrate is determined by surface and interface energetics, which can be collected in one parameter, the change in surface energy, Ω. It is common knowledge that at equilibrium conditions, Ω < 0 leads to two-dimensional (2D) growth and Ω > 0 leads to the formation of three-dimensional (3D) islands. Using classical nucleation theory, we demonstrate the existence of an interval for the chemical potential difference during growth, where 2D nucleation is favorable for sufficiently small, but positive Ω. For larger Ω, 2D nucleation is suppressed in favor of 3D nucleation. We exemplify this for two cases where epitaxial growth is performed at low supersaturation: vapor-liquid-solid growth of nanowires, and liquid phase epitaxy. First, we explain why certain axial nanowire heterostructures can be grown straight in both interface directions. Second, we explain the formation of multilayer heterostructures in liquid phase epitaxy. Finally, we discuss Stranski-Krastanov growth in a low supersaturation limit and show that there is a thermodynamically defined critical thickness, which increases with the chemical potential difference.
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