RISE – Research Institutes of Sweden
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    Secondary measurement standard for calibration of dynamic pressure sensor to bridge the gap between existing static and dynamic standards

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    A 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 10 MPa and with frequency content from 10-2 Hz to 800 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

    Predictive modeling and estimation of moisture damages in Swedish buildings: A machine learning approach

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    Identifying potential moisture damage is crucial for maintenance practices and assurance of well-being of oc cupants. However, due to limited information availability and standardization, assessing damage prevalence on the building stock scale remains understudied. By combining investigation records and building databases, this study leverages data analytic techniques and machine learning modeling to characterize damage pathology and predict its occurrence in Swedish buildings. The interrelationships between damage-specific attributes and their associations with building parameters of several damage types were analyzed using feature selection, forming the basis for developing predictive models. Results show that multilabel classifiers outperform binary classifiers for every damage type, with lead tree ensemble models achieving minimum average AUCPR and F2 of 0.85 for microbial growth, 0.87 for deformation, 0.91 for odor, and 0.95 for water leakage. The identified patterns were interpreted and verified against descriptive statistics. The binary relevance models estimate that one-third of school buildings, 20 % of commercial and office buildings, and 15 % of residential dwellings in regional building stock contain moisture damage. These findings advance the quantification of moisture damage by providing new knowledge and approaches for appraising moisture damage likelihood at aggregated and individual building levels, thereby aiding in moisture safety evaluations and preventive maintenance effortsThe research fund comes from Lansf ¨ ors ¨ ¨akringar (County Insurance) for the project predicting moisture damage in existing and new buildings using AI (machine learning) with the program ID P4:22</p

    Comparative analysis of manure treatment scenarios on climate change and eutrophication in the Baltic Sea

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    This study conducted a life cycle assessment (LCA) of manure management, identifying transportation as a major contributor to global warming and freshwater eutrophication impacts. Transporting substrates to the biogas plant was the main hotspot, highlighting a critical area for improvement. The findings emphasize the importance of method selection in geographically dependent assessments, especially in the Baltic Sea region. Characterization factors specific to Sweden revealed higher environmental impact values than those produced by the ReCiPe method, underscoring the need for regional differentiation in LCA. By optimizing manure management practices and enhancing nutrient distribution, impacts on both climate change and eutrophication can be significantly reduced, thereby lowering nutrient flow to the Baltic Sea. Combining these optimizations with transportation impact reductions further amplifies these environmental benefits, demonstrating that geographically tailored approaches in LCA offer essential insights for managing regional-scale effects. The authors are grateful for financial support from Baltic Waters.</p

    Influence of TEMPO on preparation of softwood nanofibrils and their hydrogel network properties

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    From 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

    Chemosensory vocabulary in wine, perfume and food product reviews : Insights from language modeling

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    Chemosensory sensations are often hard to describe and quantify. Language models may facilitate a systematic understanding of sensory descriptions. We accessed consumer and expert reviews of wine, perfume, and food products (English language; about 68 million words in total) and analyzed their sensory descriptions. Using a novel data-driven method based on natural language data, we compared the three chemosensory vocabularies (wine, perfume, food) with respect to their vocabulary overlap and semantic properties, and explored their semantic spaces. The three vocabularies primarily differ with respect to domain specificity, concreteness, descriptor type preference and degree of gustatory vs. olfactory association. Wine vocabulary primarily distinguishes between white wine and red wine flavors and qualities. Food vocabulary separates drinkable and edible food products and ingredients, on the one hand, and savory and non-savory products, on the other. A salient distinction in all three vocabularies is between concrete and abstract/evaluative terms. Valence also plays a role in the semantic spaces of all three vocabularies, but valence is less prominent here than in general olfactory vocabulary. Our method allows a systematic comparison of sensory descriptors in the three product domains and provides a data-driven approach to derive sensory lexicons that can be applied by sensory scientists. An earlier version of this work were presented at the 15th Pangborn Sensory Science Symposium 2023, Nantes, France. The computations were enabled by resources provided by the Swedish National Infrastructure for Computing (SNIC) at the PDC Center for High Performance Computing, KTH Royal Institute of Technology, partially funded by grants from the Swedish Research Council to T.H. (2021-03440) and J.K. O. (2020-00266), and from the Knut and Alice Wallenberg Foundation to J.K.O. (2016:0229).</p

    Pipeopsy : A Novel Method for Status Assessment of District Heating Pipes in Operation

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    This study presents a novel status assessment method for district heating (DH) pipelines in operation, which we call "Pipeopsy"(a biopsy for pipes). The method evaluates adhesion strength between the service pipe and polyurethane (PUR) insulation, which is a crucial property for the durability of DH pipes and the extent of degradation of PUR foam closest to the service pipe. This method is based on three parts: (1) measuring adhesion strength and taking samples of the foam, (2) analyzing the foam in a laboratory using Fourier-transform infrared (FTIR) spectroscopy, and (3) restoring pipeline by replacing the foam and sealing the casing by welding polyethylene plugs in the holes. Temperature dependence and measurement accuracy of the shear strength test method have also been examined, as well as correlation with the standard axial shear strength test method. The shear strength of the aged pipes shows no temperature dependence, while the quotient between the value produced with the plug method and axial method is 3.1. Compared with the standard test methods, the advantages of Pipeopsy involve small cost, less damage to pipes, and the use of simple mobile tools for taking samples and performing measurements. Importantly, testing can be performed without shutting down the operation of DH pipelines. Furthermore, the method provides not only the information on adhesion strength but also information on the extent of chemical degradation in PUR. This combination of information provides a more detailed picture of the status of pipes and can be used to make a prediction about the remaining lifetime. Pipeopsy produces many results in a short time, and better statistics, which provide a solid basis for decision-makers focused on the maintenance of DH pipes or for applying artificial intelligence. This work was financed directly by Energiforsk, the SwedishEnergy Agency. RISE and Swedish energy companies (VattenfallAB, Öresundskraft AB, Göteborg Energi AB, Jönköping EnergiAB, E. ON Energilösningar AB, Kraftringen AB, Gävle EnergiAB) contributed with in-kind work and gave access to field mea-surement test sites in their networks. Powerpipe Systems AB con-tributed with in-kind work and produced test pipe</p

    An FMI-based co-simulation framework for simulations of wave energy converter systems

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    A wave energy converter (WEC) comprises many components with distinct functions. The whole WEC system is complicated, as each component is also a complex subsystem. It is challenging to properly model and couple these subsystems to achieve a global simulation of the whole system. This study proposes an FMI-based co-simulation framework to tackle this challenge. Through the use of a co-simulation technique requiring minimal programming effort, a suite of numerical solvers serving for modelling various WEC components is coupled to create a comprehensive system model for a single WEC unit. The modules of the Ansys software, Aqwa and Rigid Dynamics, are employed to model hydrodynamic loads and motion responses. Simulink is utilized to model the power take-off (PTO) system and then integrate all models into a global simulation. The capability and accuracy of the FMI-based co-simulation framework are validated against an experimental heave decay test and verified by cross-comparing a numerical model built in SESAM. Furthermore, the framework is expanded to encompass the modelling of a large-scale wave park that includes multiple WEC units. Based on a novel WEC concept called NoviOcean, two study cases of a single unit and an 18-unit wave park are investigated. Buoy motions and power performance under several regular and irregular sea states are analysed. The hydrodynamic interactions between the units are evaluated quantitatively regarding the power performance. It is found that the interactions improve the power performance, with a maximum increase of up to 36%. This work was performed within the projects ‘Control of wave energy converters based on wave measurements, for optimal energy absorption’, funded by the Swedish Energy Agency through contract agreement no. 50197-1, and ‘INTERACT Analysis of array systems of wave energy converters with regard to interaction effects in the LCoE and fatigue analyses’, funded by the Swedish Energy Agency through contract agreement no. 50148-1. This work also received funding from the Chalmers University of Technology Foundation for the strategi cresearch project ‘Hydro- and aerodynamics’</p

    The negative association between food neophobia and sensory expectations revealed through analysis of consumers’ open-ended descriptions of seafood

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    Food neophobia (FN) – the reluctance to try novel foods – may have served a protective, evolutionary function against consuming harmful foods. In modern societies, however, FN is a major barrier that limits dietary variety and negatively impacts acceptance of both new and familiar foods. Using an online survey (adults living in Sweden, n = 946) this study investigated the influence of FN on sensory expectations of five types of seafood (salmon, herring, oysters, octopus, and seaweed; presented as labelled images). Participants rated expected liking, emotional arousal, and perceived familiarity (quantitative scales) and described the sensory aspects they expected to like and dislike using their own words (open-ended responses). The open-ended responses were evaluated qualitatively and categorized into four sensory modalities (appearance, aroma, taste, and texture). Expected liking was highest for salmon (followed by herring, seaweed, and lastly octopus and oysters), and FN was negatively associated with expected liking for all species except salmon, possibly due to being familiar and regularly consumed in Sweden. Logistic regression was used to evaluate whether the likelihood of spontaneously mentioning each sensory modality as liked or disliked varied by species and FN score. This revealed that participants were more likely to mention liking aspects of taste and texture than aroma and appearance for all samples except oysters. Texture was commonly disliked for herring, oysters, and octopus, but not for salmon and seaweed. Higher FN scores increased the likelihood of mentioning all sensory modalities as disliked and decreased the likelihood of mentioning all sensory modalities as liked. Thus, higher levels of FN were associated with both an increased focus on sensory disliking, and lower expected sensory enjoyment across all modalities. These results suggest that FN may be at least partly driven by heightened sensory responsiveness and highlight the importance of understanding expectations prior to tasting.The project has been funded by Blue Food – Centre for future seafood, with contributions from Formas – a Swedish Research Council for Sustainable Development (grant number 2020-02834) and Region Västra Götaland (grant number RUN 2020-00352).</p

    Oxy-fuel combustion of softwood in a pilot-scale down-fired pulverized combustor – Fate of potassium

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    Oxy-fuel biomass combustion can facilitate carbon capture in heat and power plants and enable negative carbon dioxide (CO2) emissions. We demonstrate oxy-fuel combustion (OFC) of softwood powder in a 100-kW atmospheric down-fired pulverized combustor run at a global oxidizer-fuel equivalence ratio of around 1.25. The simulated oxidizer was varied between oxygen (O2)/CO2 mixtures of 23/77, 30/70, 40/60 and 54/46, and artificial air. The concentrations of the main gaseous potassium (K) species: atomic K, potassium hydroxide (KOH) and potassium chloride (KCl), were measured at two positions in the reactor core using photofragmentation tunable diode laser absorption spectroscopy (PF-TDLAS). Major species were quantified by TDLAS in the reactor core and with Fourier transform infrared spectroscopy and mass spectrometry at the exhaust. Flue gas particles were collected at the exhaust employing a low-pressure impactor and analyzed by X-ray powder diffraction and scanning electron microscopy. The measured individual K species concentrations in the reactor core agreed with predictions by thermodynamic equilibrium calculations (TEC) within one order of magnitude and the sum of K in the gas phase agreed within a factor of three for all cases. Atomic K was underpredicted, while the dominating KOH and KCl were slightly overpredicted. The ratios of measured to predicted total K were similar in artificial air and OFC, but the distributions of the individual species differed at the upper reactor position. The gaseous K species and fine particle concentrations in the flue gas were directly proportional to the O2 content in the oxidizer. The crystalline phase compositions of the coarse mode particles were rich in K- and calcium-containing species. The fine mode particles, which contained most of the K, consisted mainly of K2SO4 (94%) and K3Na(SO4)2, which is in excellent agreement with TECs of gas phase condensation. As supported by the solid phase analysis, complete sulfation of K species was achieved for all studied cases. A CO2 purity (dry) of up to 94% was achieved for OFC. The authors acknowledge financial support from the Swedish Energy Agency and the Kempe Foundations. The long-term support from the Swedish Strategic Research Environment Bio4Energy for our activities is highly appreciated.</p

    Consequential life cycle assessment of urban source-separating sanitation systems complementing centralized wastewater treatment in Lund, Sweden

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    This study examined various source-separating sanitation systems to evaluate their environmental performance, providing decision-makers with insights for selecting an appropriate system for a newly developed neighborhood in Sweden. A full consequential LCA was conducted to account for resource recovery and substitution. The local wastewater treatment plant WWTP was modeled as a reference. Secondly, a urine recycling system was introduced to treat 75 % of the collected urine, with the remainder piped to the WWTP. Thirdly, a black and greywater (BW&amp;GW) treatment system handling all generated wastewater was examined. Finally, a hybrid source-separating system combining urine, black, and greywater was investigated. The results indicated that the four scenarios exhibited global warming potentials (GWP) of 78, 62, 32, and 24 kg CO2-eq per PE/ y. Recycling urine as fertilizer led to a 20 % reduction in the GWP of the reference. It also reduced other impact categories, with a 55 %, 65 %, and 45 % reduction in eutrophication, ozone depletion, and acidification, respectively. The BW&amp;GW system achieved a 60 % reduction over the reference GWP, mainly due to fertilizer, biogas, and cleanwater recovery. Integrating urine, black, and greywater recycling in the final scenario achieved a 25 % reduction compared to the BW&amp;GW scenario, primarily due to lowering of the ammonia stripping GWP and the additional fertilizer recovery. Based on sensitivity analyses, switching citric acid for sulfuric acid reduced the GWP of the urine stabilization unit process by 101 %, from 15.47 to -0.14 kg CO2-eq per PE/ y. Ultimately, the findings suggest that the fully decentralized source-separating sanitation system incorporating urine, blackwater, and greywater recycling, particularly when combined with 70 % energy recovery at the urine concentrator, is most favorable. ©

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