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INFLUENCE OF GLASS BREAKAGE ON VENTILATION AND FIRE BEHAVIOUR IN LARGE TIMBER COMPARTMENTS: A NUMERICAL SIMULATION STUDY
No full textFlexibility-centric sizing and optimal operation of building-thermal energy storage systems : A systematic modelling, optimization and validation approach
No full textThe increasing integration of renewable energy sources (RES) and the transition towards a decarbonized energy sector present significant challenges, particularly in demand-side management. Thermal energy storage (TES) systems offer a cost-effective solution for enhancing energy flexibility in building heating systems. However, improper sizing and operation of TES systems can lead to increased investment costs and energy losses. To bridge this gap, this study proposes a novel, optimization-based framework for the systematic sizing and operation of TES systems. The methodology encompasses two key components: (1) an innovative TES sizing framework that integrates system modelling and optimization-based sizing leveraging historical thermal load data; (2) validation and performance evaluation of the sizing outputs through building energy simulations across three diverse building types and climatic conditions. Key findings demonstrate the framework’s ability to adapt to various scenarios, achieving operational cost reductions of up to 35 % and significantly enhancing the energy flexibility in terms of flexibility factor by up to 1.03. Furthermore, the proposed framework is shown to effectively optimize TES capacities to unique building load patterns. These results highlight the framework’s potential as a robust tool for optimizing TES in buildings, contributing to flexible and cost-efficient energy systems. This work was supported by the Swedish Energy Agency under Grant number 51544-1 and the European Union’s H2020 program under Grant number 101096789.</p
Direct conversion of sawdust into biobased aviation fuel precursor via atmospheric catalytic hydropyrolysis process
No full textThis research aimed to develop catalyst and technology design to selectively convert sawdust into bio jet fuel (BJF) components via ex-situ catalytic hydropyrolysis (CHP) process. Design of catalyst configuration was carried out considering the fact that an efficient catalyst for biomass pyrolysis process requires (i) an improved diffusion rate of reactants/products to and from the catalyst active sites, (ii) suppression of secondary reactions, and (iii) prevention of deactivation mechanisms. Hence, sawdust was hydropyrolyzed in a customized continuous pyrolysis system and then the pyrolysis vapors were upgraded while passing through a bed of a well-designed guard catalyst (CatG) followed sequentially by a suitable hydroconversion catalyst (CatH). The morphology and chemical structure of CatG and CatH were synergistically designed to enhance the selectivity towards aromatic hydrocarbons in the range of jet fuel chemicals for 75 %. Effects of different process parameters, such as structure and morphology of CatG, catalyst upgrading temperature (350 and 400 °C), pyrolysis gas environment (N2, H2/N2, and air/N2), concentration of CatG active sites (8, 17, 33, and 50 wt%), and durability of catalysts, on the process efficiency concerning reaction selectivity towards BJFs, heating value of the pyrolysis products, and carbon efficiency of the whole process were investigated. Specifically, the durability of combined catalysts was evaluated for four times and the results showed that the catalysts combination resulted in similar selectivity to BJFs during recycling tests. The maximum selectivity to BJFs (42 %) was achieved at 400 °C, WHSV 3 h−1, reaction time 3 h, carrier gas H2/N2, and CatG 33 wt%. The authors would like to thank the Swedish Energy Agency for financially supporting this study via the project P2021-00086.</p
Contaminations from Lithium-Ion Battery Fires—Per- and Polyfluoroalkyl Substances (PFAS) in Soot
No full textFluorinated substances are widely used in the different components of the lithium-ion battery cell, such as electrode binders, electrolyte, additives and separator materials. To date, most studies regarding the fluorinated contaminations from lithium-ion battery fires are focused on the gases formed, whereas the solids produced are not as well characterized. Here, we present an experimental study investigating the occurrence of per- and polyfluoroalkyl substances, in soot and particulates formed after thermal runaway in lithium-ion battery cells. Per- and polyfluoroalkyl substances were detected in every battery cell test performed in this study. The concentration of per- and polyfluoroalkyl substances ranged between 20 to 130 ng/gsoot. Extrapolation of data gives an estimated release of 10 to 60 µg of per- and polyfluoroalkyl substances per kg battery cells. Among the 22 per- and polyfluoroalkyl substances analyzed, perfluorobutanesulfonic acid and perfluorobutanoic acid were found in the highest concentrations for all samples. Interestingly, perfluorooctanoic acid was detected in all tests, in concentrations ranging between 0.05 to 0.62 ng/gsoot. These findings are of importance not only for the purpose of decontamination after thermal runaway events, but also when it comes to the lithium-ion battery recycling processes. This work was funded by Vinnova (Grant No. 2019-00064) through Batteries Sweden (BASE)</p
Risk Classification Analysis Service for the EU AI Act
No full textThis report presents the Risk Classification Analysis Service developed at RISE to support early implementation of the EU Artificial Intelligence Act (Regulation (EU) 2024/1689). The service offers a structured methodology for preliminarily assessing whether AI systems may fall under the Act’s High-Risk category and for identifying related compliance measures. It combines questionnaire-based information collection, analytical workshops, and preliminary classification, resulting in a final report that documents assumptions, explains the rationale for the classification, highlights compliance gaps, and provides recommendations for preparation toward conformity assessment. Pilot applications in manufacturing and energy showed that classification outcomes depend strongly on deployment context and on how regulatory criteria are interpreted, particularly when determining whether an AI system falls within an Annex III area, supports critical-infrastructure operation, or functions as a safety component of an Annex I–regulated product. The report also summarises key findings, challenges and lessons learned from applying the methodology in practice.CitCom.a
Hybrid Discrete-Finite Element method for biaxially-discretized structures
No full textThe HybriDFEM method, short for Hybrid Discrete-Finite Element Method, combines both discrete and finite element approaches in a single numerical model: the method adopts a discrete representation of the structure, but the formulation is designed to integrate continuous parts that can be simulated by the Finite Element Method, allowing hybrid numerical mock-ups to be built. The scope of application of the method is expanded from its original development for uniaxially-discretized (1D) structures to modeling biaxially-discretized (2D) structures and systems of beams connected through rigid-node connections. The possibility to integrate finite elements within HybriDFEM in 2D is initially formalized. A two-step contact detection algorithm, in which the interface detection is preceded by a preliminary rough detection, is then presented. Finally, different approaches to modeling contact are introduced, depending on whether it is meant to reflect the behavior of a continuous material, flexible interfaces, or point-wise contact. These new capabilities of the 2D HybriDFEM method are validated on a series of selected examples including solutions from analytical models, classical finite elements, and limit analysis; among others, the HybriDFEM method is used to evaluate the axial and shear stress distribution in a linear elastic beam with negligible error relative to analytical solutions, and to predict the collapse load of in-plane loaded masonry frames with an error below 0.05% compared to solutions from limit analysis. The adequacy of the method to enhance discrete simulations by integrating finite elements is illustrated in a conclusive example via the pushover analysis of a flexible masonry frame
Influence of TEMPO on preparation of softwood nanofibrils and their hydrogel network properties
No full textFrom an economic and environmental perspective, the use of less chemicals in the production of cellulose nanofibrils (CNFs) is advantageous. In this study, we investigated the oxidation (TEMPO/NaClO2/NaClO, pH 6.8) of softwood (SW) particles with varying amounts of TEMPO (16, 8 or 0 mg g−1 of wood). Following, TEMPO-oxidized SW nanofibrils (TO-SWNFs) were obtained by nanofibrillation and their size, morphology, and crystallite size were assessed. Hydrogel networks of TO-SWNFs were prepared and mechanical properties were measured in dH2O and phosphate buffered saline (PBS) to compare their performance for possible biomedical applications such as wound dressings. The results reveal that the presence of TEMPO is of importance for TO-SWNF network properties, presenting higher eq. H2O absorption (≈2500 %) and elongation at break (≈10 %) with good wet strength (≈180 kPa). In addition, a decrease in use of TEMPO catalyst from 16 to 8 mg g−1 of wood is possible, without detrimental effects on hydrogel network properties (dH2O absorption ≈ 2000 %, elongation at break ≈ 13 %, wet strength ≈ 190 kPa) related to applications as wound dressings. This project was funded by the Swedish Foundation for Strategic Research within the HEALiX project [RMX18-0039]. Funding through Stiftelsen Gunnar Sundblads forskningsfond through Young Researcher's Award is acknowledged. The authors are grateful to Junko Takahashi-Schmidt and Sonja Viljamaa at Umeå Plant Science Centre (UPSC) and the Biopolymer Analytical Platform (BAP) at UPSC/SLU supported by Bio4Energy for their help with pyrolysis-GC/MS and acetyl bromide lignin analysis. The authors thank the Swedish Metabolomics Center (SMC) for the RDA software and Jessica Lindén for their contribution in retention experiments. Illustrations were created with BioRender.</p
Secondary measurement standard for calibration of dynamic pressure sensor to bridge the gap between existing static and dynamic standards
No full textA secondary measurement standard filling the gap between the available static and dynamic standards was developed. The standard utilizes a quick-opening valve and bursting diaphragms to generate step-like pressures with amplitude of few kilopascals to 10Â MPa and with frequency content from 10-2 Hz to 800Â Hz. An important design feature of the developed standard lies in the usage of aluminium diaphragms, allowing short rise times and high frequency content. The standard is based on two reference sensors, calibrated statically and dynamically. The reference sensors showed a linear dynamic response in the intermediate frequency range and was in good agreement with the static calibration results. Therefore, extrapolation of shock tube results was implemented. To demonstrate the capabilities of the developed standard, three pressure measurement systems were characterized, and their respective dynamic response was calculated. The results show that the developed standard can provide calibration information that are not currently available.The financial support by the Swedish Governmental Agency for Innovation Systems, VINNOVA [grant number 2021-04166] is gratefully acknowledged.</p
Quantifying the Abundance of Alkane Moieties in Lignins with FTIR Spectroscopy and PLS Regression; Estimating Grafting Degree of Esterification
No full textAs society is rapidly converting from fossil-based materials to greener alternatives, the valorization of lignin through chemical modification has been given considerable attention. Characterizing this highly heterogeneous biopolymer is a constant challenge, and an emerging strategy for dealing with variations in material characteristics is combining traditional analytical techniques with chemometrics, such as Fourier-transform infrared (FTIR) spectroscopy with partial least squares regression (PLSR). Here, a calibration data set was built based on FTIR spectra and the total carbon-hydrogen bond (CHB) content of mixtures of technical lignins and alkanes, meant to emulate esterified samples. From this data, a PLSR model was built which predicted the CHB content of esterified lignin reaction products with an RMSECV=5.685 mmol/g and RMSEPred=5.827 mmol/g, and from which the weight percentage of ester-to-lignin was determined. When compared to wet-chemical analysis, good agreement between the techniques was found with an obtained RMSEPred=8.3 % and a R2Train=0.9752 for the degree of esterification. This indicates high model predictability and goodness of fit, and that the calibration data set successfully emulated esterified lignin samples. This work was part of the “LignoWax – Green Wax Inhibitorsand Production Chemicals based on Lignin” project (grantnumber 326876). The authors thank the Norwegian ResearchCouncil, Equinor ASA and ChampionX Norge AS for financialsupport, and the staff at RISE PFI AS for technical support.</p
HCT City : Omvärldsanalys och prioriteringar för effektivare masstransporter i städer
No full textDenna rapport är resultatet av arbetspaket 2: Omvärldsanalys och prioriteringar inom projektet HCT City: Fallstudie massgods i städer, finansierats av Vinnova. Arbetet har utförts mellan 2021 och 2024. Syftet med hela projektet har varit att undersöka potentialen för High Capacity Transport (HCT) i urban miljö, med särskilt fokus på masstransporter av schaktmassor. Bygg- och anläggningstransporter står för cirka 20 % av Sveriges totala transportarbete och 50 % av transportarbetet i städer (viktmässigt). Trots detta har området tidigare varit under utforskat. Projektet fokuserar på fyra huvudområden: infrastruktur, fordon, tillträdeskontroll inklusive samlat regelverk och tillsyn samt digitalisering och koordinering av byggprocessen. Omvärldsanalysen omfattar internationella erfarenheter, särskilt från Finland, Danmark, Australien och Sydafrika. Finland har varit föregångare med införandet av 76-tons fordon och uppnått betydande minskningar i CO₂-utsläpp och transportarbete. I Sverige tillåts nu längre fordonskombinationer på upp till 34,5 meter och 74 ton (BK4), vilket ger möjligheter till effektivare transporter, dock med varierande tillgång till sådant vägnät i kommunerna. Rapporten ger också en nulägesbeskrivning av nuläget i Sverige avseende HCT för masstransporter. En viktig del av omvärldsanalysen är en intervjustudie från Finland som undersöker införandet av HCT med fokus på masstransporter i städer. Intervjustudien undersöker hur man löst regelverk och tillgänglighet, fordon och infrastruktur i Finland samt erfarenheter från detta. Dessutom beskrivs pågående automatisering och digitalisering av massahantering i Helsingfors med hjälp av flera digitala verktyg och plattformar. Även digitalisering av transportdokument håller på att implementeras (2022) Trafikarbetet har minskat samtidigt som att transportarbete ökat i Finland tack vare regelförändring och implementering av HCT-koncept under perioden 2014-2021 i takt med att fordonsparken successivt blir effektivare visar statistik. Syftet med omvärldsanalysen var dels att lära av andra goda exempel, dels att få hjälp med prioriteringar inom projektet och fallstudierna kring viktiga frågor att utreda inom projektet. Arbetet har varit iterativt och lärdomar från detta arbetspaket har successivt tagits tillvara i arbetet i de olika arbetspaketen i projektet. Sammanfattningsvis visar omvärldsstudien att HCT i urban miljö kan leda till betydande miljövinster, ökad transporteffektivitet och förbättrad trafiksäkerhet, förutsatt att infrastrukturella och regelmässiga hinder hanteras. Rapporten identifierar behovet av ett sammanhållet vägnät med samordnade regler över kommun- och regiongränser för att möjliggöra bredare implementering av HCT i städer. Utmaningar kvarstår i form av varierande bärighetsklassning, olika kommunala prioriteringar samt behov av fortsatt forskning ochRapporten är framtagen med ekonomiskt bidrag från Vinnova FFI.</p