RISE – Research Institutes of Sweden
Not a member yet
7718 research outputs found
Sort by
Carbon-coated fiber for optoelectronic strain and vibration sensing
No full textIn this article, we report on a carbon-coated optical fiber that is suitable to be used simultaneously as a transmission medium and as a sensor. It consists of a standard single mode fiber (SMF) sleeved in two layers of coating, which provide protection and isolation from external elements. The inner layer is made of carbon, whereas the outer is made of polymer. When the fiber is subjected to mechanical stress, the electrical resistance of the carbon layer changes accordingly. The voltage variations caused by the former can be measured with high accuracy and without interfering with the light propagating through the SMF. In this work, the feasibility of this operating principle is demonstrated in a low coherence Michelson interferometer in which electrical and optical signals were measured simultaneously and compared to each other. Results indicate that electrical measurements are as precise as the optical ones and with linear behavior, reaching a sensitivity of 1.582 mV/με and able to detect vibrations down to 100 mHz. © 2024 The AuthorsThis work was supported by the grants I\u202F+\u202FD\u202F+\u202Fi/PID2021-122505OBC31, TED2021-129959B-C21, PDC2022-133053-C21, RTC2019-007194-4 and PDC2022-133885-100 funded by MCIN / AEI/10 . 13039/501100011033 , by \u201C ERDF A way of making Europe\u201D, by the \u201C European Union Next Generation EU/PRTR \u201D. The research work is also supported by the Grant No. IT11452-22 and funded by the Basque Government , by ELKARTEK 2023 (\u03BC4Smart -KK-2023/00016 , MINAKU KK-2022/00080 and Ekohegaz II-KK-2023/00051 ) and by the University of the Basque Country (UPV/EHU)</p
Experimental and numerical investigations of propeller open water characteristics in calm water and regular head waves
No full textPropeller Open Water (POW) performance of a non-ventilating and fully-submerged propeller in model-scale is investigated in calm water and regular head waves using experimental tests (EFD) and Computational Fluid Dynamics (CFD). Laminar flow dominance is observed in calm water, particularly at higher advance ratios. Nevertheless, the findings in waves suggest increased turbulence, stemming from both the wave orbital velocities and the presumably increased turbulence level produced by the wave maker in the towing tank. Analysis of the CFD results obtained from the incident flow field and single-blade force and moment leads to the speculation that the observed discrepancies are associated with the inevitable asymmetric conditions and mechanical interference in the experiments which were absent in CFD. These can potentially alter the flow over the blades resulting in a different flow transition, separation, and coherent turbulent structure formation and hence forces and moments. The altered propeller performance in waves in comparison to calm water underlines the significance of waves on the propulsive factors and propeller design. © 2024 The AuthorsThis research is funded by The Swedish Transport Administration through Lighthouse (Swedish Maritime Competence Center) . The experimental measurements are carried out at SSPA Towing Tank. The simulations were performed on the resources provided by the National Academic Infrastructure for Supercomputing in Sweden (NAISS) and the Swedish National Infrastructure for Computing (SNIC) at Chalmers Centre for Computational Science and Engineering (C3SE) and National Supercomputer Center at Link\u00F6ping University (NSC) partially funded by the Swedish Research Council through grant agreements no. 2022-06725 and no. 2018-05973 . Gabriele Mazza is acknowledged for conducting the open water experiments.</p
Anion Architecture Controls Structure and Electroresponsivity of Anhalogenous Ionic Liquids in a Sustainable Fluid
No full textThree nonhalogenated ionic liquids (ILs) dissolved in 2-ethylhexyl laurate (2-EHL), a biodegradable oil, are investigated in terms of their bulk and electro-interfacial nanoscale structures using small-angle neutron scattering (SANS) and neutron reflectivity (NR). The ILs share the same trihexyl(tetradecyl)phosphonium ([P6,6,6,14]+) cation paired with different anions, bis(mandelato)borate ([BMB]−), bis(oxalato)borate ([BOB]−), and bis(salicylato)borate ([BScB]−). SANS shows a high aspect ratio tubular self-assembly structure characterized by an IL core of alternating cations and anions with a 2-EHL-rich shell or corona in the bulk, the geometry of which depends upon the anion structure and concentration. NR also reveals a solvent-rich interfacial corona layer. Their electro-responsive behavior, pertaining to the structuring and composition of the interfacial layers, is also influenced by the anion identity. [P6,6,6,14][BOB] exhibits distinct electroresponsiveness to applied potentials, suggesting an ion exchange behavior from cation-dominated to anion-rich. Conversely, [P6,6,6,14][BMB] and [P6,6,6,14][BScB] demonstrate minimal electroresponses across all studied potentials, related to their different dissociative and diffusive behavior. A mixed system is dominated by the least soluble IL but exhibits an increase in disorder. This work reveals the subtlety of anion architecture in tuning bulk and electro-interfacial properties, offering valuable molecular insights for deploying nonhalogenated ILs as additives in biodegradable lubricants and supercapacitors. We acknowledge the support of the Australian Centre for Neutron Scattering, ANSTO, and the Australian Government through the National Collaborative Research Infrastructure Strategy (NCRIS), in using the neutron research infrastructure used in this work via ACNS proposal P13958 on the BILBY SANS and proposal P8264 on the PLATYPUS NR instrument. We gratefully acknowledge Institut Laue-Langevin (ILL), France, for access to SuperADAM (doi:10.5291/ILL-DATA.9-13-1006). We acknowledge the support of the Australian Government in provision of access to ANSTO's National Deuteration Facility which is partly funded through NCRIS. Prof. Oleg N. Antzutkin (Luleå University of Technology) is gratefully acknowledged for providing the ILs. The authors thank Prof. Thomas Norrby (KTH Royal Institute of Technology and Nynas AB) for insightful discussions on 2-EHL properties and applications. The authors would also like to thank Dr. Alexei Vorobiev for his support during the SuperADAM beamtime and Dr. Brando Adranno, Dr. Olivier Renier, Anthony Boudier, and Filip Mehler for their experimental support. Daniel Morris is thanked for valuable assistance performing SANS experiments. SL and GP also thank Dr. Adrian Iovan (KTH Nanolab) for his help with the preparation of the gold electrode via the electron beam evaporator. The Knut and Alice Wallenberg Foundation (Project no. KAW2012.0078), the Swedish Research Council, VR (Project no. 2017-04080), the Swedish Foundation for Strategic Research (Project no. EM16-0013, "REFIT"), Vinnova (Project no. 2020-03801), and Villum Foundation (Villum Investigator awards to AVM) are acknowledged for their financial support. We also thank the Danish Agency for Science, Technology, and Innovation for funding the instrument center DanScatt (Grant no. 2021 7129-00006B).</p
An indicator framework to guide food system sustainability transition – The case of Sweden
No full textWell-aligned food policies are needed at both national and international level to guide food system transformation towards sustainability. Rigorous indicator frameworks are essential in order to facilitate discussion of priorities, enable comparisons, assessment and progress monitoring, and ensure accountability. In this study, we develop a national framework for a sustainable food system, using Sweden as a case. Our framework, the Food System Sustainability House, advances the literature on sustainable food system frameworks in three distinct ways. Firstly, it is tailored to a specific national context (Sweden in our case); secondly, it distinguishes between impacts of domestic production arising within territorial boundaries and impacts related to Swedish consumption independent of country of origin; and thirdly, to facilitate policy priorities, it suggests how different dimensions of sustainability are interlinked at a conceptual level. From a scientific perspective, the Food System Sustainability House postulates the interlinkages between the societal objectives of the food system, the environmental foundations on which production takes place, and the economic system and governance which in the framework are suggested to function as enablers for an overall sustainable system. From a policy perspective, the framework provides a much-needed basis for assessing food system sustainability by suggesting indicators within a comprehensive set of sustainability themes at national level for monitoring distinct perspectives. It also provides the necessary basis for a discussion on how sustainability dimensions are interlinked. The study was part of Mistra Food Futures (DIA 2018/24 #8), a research programme funded by Mistra (The Swedish Foundation for Strategic Environmental Research). Research funding is gratefully acknowledged. The funder had no impact on the study.</p
Effect of degraded environmental conditions on the service behavior of a X65 pipeline steel not designed for hydrogen transport
No full textWith the international drive to deploy green energies and decarbonized intermediates in the place of fossil fuel sources, a large number of developed countries are actively preparing for a future where hydrogen plays a strategic role as an energy storage medium. Producing and using hydrogen requires the rapid expansion of a dedicated, economically viable industrial sector. Nevertheless, questions on how to safely store, transport and distribute hydrogen remain an important priority today. In countries with existing natural gas transport grids, the possibility to retrofit these networks to store and transport hydrogen-natural gas blends is being studied. A key challenge is to evaluate how pressurized H2 would interact with steel structures with regards structural embrittlement of the latter, with a view to exploiting existing transport infrastructures for storage and transport applications. In this work, we evaluate the H2-performance of a non-hydrogen service ×65 pipeline steel. The cracking susceptibility of this steel grade has been evaluated at 100 bar H2 using slow strain rate testing, Constant strain testing and fracture toughness measurements. Accompanying hydrogen permeation tests under pressure provide diffusion data and elucidate the discussion. Exposures were carried out in dry or wet H2 and with or without H2S contamination at levels representative of biogas. The results underline that the impact of dry or wet hydrogen on this grade are moderate. The presence of traces of H2S together with humidity could risk seriously degrading the mechanical performance of the ×65 steel grade. © 2023 The AuthorsCorrespondence Address: C. Mendibide; Institut de La Corrosion (French Corrosion Institute), Part of RISE - ZA Du Parc, Fraisses, Secteur Gampille, F-42490, France; </p
Identification and quantification of valuable platform chemicals in aqueous product streams from a preliminary study of a large pilot-scale steam explosion of woody biomass using quantitative nuclear magnetic resonance spectroscopy
No full textSteam explosion breaks down the polymeric matrix and enables the recovery of valuable compounds from lignocellulosic feedstock. In the steam explosion process, biomass is treated with high-pressure steam which subsequently generates large quantities of a condensed aqueous liquid (process effluent) and a filtered aqueous liquid (filtrate) that contain furfural, 5-hydroxymethylfurfural, 5-methylfurfural, methanol, and acetic acid as major constituents. This study addresses the identification and quantification of value-added chemicals in the aqueous product streams using quantitative analytical nuclear magnetic resonance spectroscopy with water suppression. This work reports a screening study for two different types of sawdust (Norway spruce and birch) at two different scales (4 L and 10 L reactors) using different reaction temperatures (190–223 °C) and corresponding pressures (13–24 bar), with and without the addition of SO2 gas. The duration of all experiments was 8 min. The process effluents contained acetic acid, methanol, formic acid, 5-methylfurfural, and furfural. Acetic acid (0.5 g/kg dry input biomass) and furfural (1.0 g/kg dry input biomass) were more abundant than methanol, formic acid, and 5-methylfurfural for both feedstocks. The addition of SO2 increased the furfural yields, indicating more efficient hydrolysis of hemicelluloses under acidic conditions. Filtrate samples also contained 5-hydroxymethylfurfural, with the highest concentrations (5.7–6.0 g/kg dry input biomass) in the filtrates from spruce. The different feedstocks and steam explosion temperatures strongly influenced the overall yields of the target compounds, in some cases tripling the concentrations. The results can be used to improve the profit margins in a pellets and chemicals biorefinery, as demonstrated in the ArbaOne pellets plant. Funding details: 509-42/16; Funding details: Horizon 2020 Framework Programme, H2020, 818349; Funding details: Norges Forskningsråd, 226244/F50, 309970; Funding details: Bergens Forskningsstiftelse, BFS-NMR-1; Funding text 1: Open access funding provided by University of Bergen (incl Haukeland University Hospital). This work received funding from Arbaflame AS through the Research Council of Norway under grant agreement No 309970 and the European Union’s Horizon 2020 research and innovation programme under grant agreement No 818349.; Funding text 2: The authors gratefully acknowledge Lund University Biobased Industry Research Center and Kai Toven at RISE PFI AS for providing samples. This work was partly supported by Bergen Research Foundation (BFS-NMR-1), Sparebankstiftinga Sogn og Fjordane (509-42/16), and the Research Council of Norway through the Norwegian NMR Platform, NNP (226244/F50).</p
Drivers of a more sustainable future food system – Lessons from Sweden
No full textThe global food sector is one of the most impactful sectors in the world, necessitating an urgent shift towards more sustainable practices. Sweden has made great progress in putting sustainability on the agenda as a strategic component of its national development strategy. Still, understanding how a full-scale sustainable food system can be achieved in practice and the drivers of such a transition remain unclear. In this study, we first empirically explore these drivers, their interdependencies and how these affect the Swedish food system’s progress towards its sustainability objectives. Then, we assess which scenarios for the future food system in Sweden perform better with regard to sustainability considerations. For the first objective, we utilised the DEMATEL technique to identify and quantify the cause-and-effect relationships among these drivers. The results showed that revenue and the use of toxic materials are key drivers for food systems’ sustainability in Sweden, suggesting a path for system improvement focus areas in the future. For the second objective, we applied TOPSIS as a decision-making method for assessing the sustainability of four different future scenarios for the Swedish food system. The outcomes suggest that food tech is the most sustainable scenario among the ones considered. The findings of this study will collectively aid in promoting sustainable consumption, encouraging a shift towards a more sustainable agrifood system in Sweden, a leading nation in sustainability efforts. This study was performed as part of the research programme MISTRA Food Futures (www.mistrafoodfutures.org) and was funded by MISTRA – The Swedish Foundation for Strategic Environmental Research. We gratefully acknowledge all survey respondents. Additionally, in the process of constructing the literature review for the identification of indicators, we leveraged the resources of a separate research initiative supported by the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas) within the national centre FINEST – Food Innovation for Sustainable System Transition [Grant no. 2020-02839]. </p
Parametric learning of time-advancement operators for unstable flame evolution
No full textThis study investigates the application of machine learning, specifically Fourier neural operator (FNO) and convolutional neural network (CNN), to learn time-advancement operators for parametric partial differential equations (PDEs). Our focus is on extending existing operator learning methods to handle additional inputs representing PDE parameters. The goal is to create a unified learning approach that accurately predicts short-term solutions and provides robust long-term statistics under diverse parameter conditions, facilitating computational cost savings and accelerating development in engineering simulations. We develop and compare parametric learning methods based on FNO and CNN, evaluating their effectiveness in learning parametric-dependent solution time-advancement operators for one-dimensional PDEs and realistic flame front evolution data obtained from direct numerical simulations of the Navier-Stokes equations. The author gratefully acknowledges the financial support by the Swedish Research Council (VR-2019-05648). The simulations were performed using the computer facilities provided by the Swedish National Infrastructure for Computing (SNIC) at PDC, HPC2N and ALVIS. This work benefited from the preliminary study conducted during Ludvig Nobel's master's thesis at Lund University in 2022.</p
Exploring the Elastomer Influence on the Electromechanical Performance of Stretchable Conductors
No full textStretchable electronics has received major attention in recent years due to the prospects of integrating electronics onto and into the human body. While many studies investigate how different conductive fillers perform in stretchable composites, the effect of different elastomers on composite performance, and the related fundamental understanding of what is causing the performance differences, is poorly understood. Here, we perform a systematic investigation of the elastomer influence on the electromechanical performance of gold nanowire-based stretchable conductors based on five chemically different elastomers of similar Young’s modulus. The choice of elastomer has a huge impact on the electromechanical performance of the conductors under cyclic strain, as some composites perform well, while others fail rapidly at 100% strain cycling. The lack of macroscopic crack formation in the failing composites indicates that the key aspect for good electromechanical performance is not homogeneous films on the macroscale but rather beneficial interactions on the nanoscale. Based on the comprehensive characterization, we propose a failure mechanism related to the mechanical properties of the elastomers. By improving our understanding of elastomer influence on the mechanisms of electrical failure, we can move toward rational material design, which could greatly benefit the field of stretchable electronics.
FE[r]Chain : Enforcing Fairness in Blockchain Data Exchanges Through Verifiable Functional Encryption
No full textFunctional Encryption (FE) allows users to extract specific function-related information from encrypted data while preserving the privacy of the underlying plaintext. Though significant research has been devoted to developing secure and efficient Multi-Input Functional Encryption schemes supporting diverse functions, there remains a noticeable research gap in the development of verifiable FE schemes. Functionality and performance have received considerable attention, however, the crucial aspect of verifiability in FE has been relatively understudied. Another important aspect that prior research in FE with outsourced decryption has not adequately addressed is the fairness of the data-for-money exchange between a curator and an analyst. This paper focuses on addressing these gaps by proposing a verifiable FE scheme for inner product computation. The scheme not only supports the multi-client setting but also extends its functionality to accommodate multiple users - an essential feature in modern privacy-respecting services. Additionally, it demonstrates how this FE scheme can be effectively utilized to ensure fairness and atomicity in a payment protocol, further enhancing the trustworthiness of data exchanges. This work was funded by the HARPOCRATES EU research projects(No. 101069535) and SWARMCHESTRATE (No. 101135012).</p