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Numerical parametric study on the influence of location and inclination of large-scale asperities on the shear strength of concrete-rock interfaces of small buttress dams
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The ZEN definition – a guideline for the ZEN pilot areas. Version 4.0
Get PDFThis fourth and final version (version 4.0) of the ZEN definition guideline report builds upon V1.0, V2.0 and V3.0 of the ZEN definition guideline reports and a series of ZEN definition reports. This report highlights that an nZEN balance is required instead of point allocation in the GHG emissions category. Reference, limit, and target values have been added to the energy and power categories. The mobility and economy KPIs and point system have been reviewed based on testing in the ZEN pilot project Ydalir, and minor adjustments have been made to the urban form and land use KPIs. The process chapter has been moved to a separate process guideline report.publishedVersio
Drowsiness Detection Using Federated Learning: Lessons Learnt from Dealing with Non-IID Data
Get PDFThe privacy of personal data is paramount in the realm of assisted living and digital healthcare. Federated Learning (FL), with its decentralised model training approach, has emerged as a compelling solution to reconcile the need for personalised models with the requirement to protect sensitive personal information. By allowing model training to occur locally on user devices without centralising raw data, FL is intended to strike a balance between personalisation and privacy. While the potential benefits of FL in assisted living and digital healthcare are substantial, practical implementation poses significant challenges. One of them is the non-Independently and Identically Distributed (non-IID) nature of personal data. Unlike centralised datasets, non-IID data exhibits inherent variability across different individuals, as well as their surrounding contexts. Unfortunately, many research approaches in this domain often overlook the nuances of non-IID data, potentially leading to models that lack robust generalisation across diverse healthcare scenarios. To highlight the importance of this challenge, in this paper, we report on our hands-on experience of building a FL system for drowsiness detection using non-IID data. We compare this federated setup with a traditional, centralised approach to model training by identifying and discussing the associated challenges from multiple perspectives, as well as possible solutions and recommendations for further research.publishedVersio
Prototyping in Polymethylpentene to Enable Oxygen-Permeable On-a-Chip Cell Culture and Organ-on-a-Chip Devices Suitable for Microscopy
Get PDFWith the rapid development and commercial interest in the organ-on-a-chip (OoC) field, there is a need for materials addressing key experimental demands and enabling both prototyping and large-scale production. Here, we utilized the gas-permeable, thermoplastic material polymethylpentene (PMP). Three methods were tested to prototype transparent PMP films suitable for transmission light microscopy: hot-press molding, extrusion, and polishing of a commercial, hazy extruded film. The transparent films (thickness 20, 125, 133, 356, and 653 µm) were assembled as the cell-adhering layer in sealed culture chamber devices, to assess resulting oxygen concentration after 4 days of A549 cell culture (cancerous lung epithelial cells). Oxygen concentrations stabilized between 15.6% and 11.6%, where the thicker the film, the lower the oxygen concentration. Cell adherence, proliferation, and viability were comparable to glass for all PMP films (coated with poly-L-lysine), and transparency was adequate for transmission light microscopy of adherent cells. Hot-press molding was concluded as the preferred film prototyping method, due to excellent and reproducible film transparency, the possibility to easily vary film thickness, and the equipment being commonly available. The molecular orientation in the PMP films was characterized by IR dichroism. As expected, the extruded films showed clear orientation, but a novel result was that hot-press molding may also induce some orientation. It has been reported that orientation affects the permeability, but with the films in this study, we conclude that the orientation is not a critical factor. With the obtained results, we find it likely that OoC models with relevant in vivo oxygen concentrations may be facilitated by PMP. Combined with established large-scale production methods for thermoplastics, we foresee a useful role for PMP within the OoC field.publishedVersio
The Potential of Cast Stock for the Forging of Aluminum Components within the Automotive Industry
Get PDFIn the automotive industry, there is a drive to reduce environmental impact, energy consumption, and costs related to the manufacturing of forged aluminum suspension components. The replacement of extruded stock with cast forging stock is one option that offers substantial potential for such savings. The casting technology, low-pressure casting (LPC), allows for production of high-quality cast forging stock with minimal surface segregation and smaller diameters than those achieved with traditional casting technologies. This study is a proof-of-principle, conducted to directly compare the microstructure and mechanical properties of LPC and extruded material after forging, through both generic and full-scale industrial forging trials. The results show the advantages of the cast material, including higher robustness against surface grain growth after forging and a positive correlation between mechanical properties, both strength and ductility and the introduction of plastic deformation. Overall, the work demonstrates how forged aluminum components produced from LPC forging stock can achieve mechanical properties and performance, on par with extruded forging stock, showcasing industrial relevance through the production of a safety-critical automotive component.publishedVersio
Computational Rhinology: Unraveling Discrepancies between In Silico and In Vivo Nasal Airflow Assessments for Enhanced Clinical Decision Support
No full textComputational rhinology is a specialized branch of biomechanics leveraging engineering techniques for mathematical modelling and simulation to complement the medical field of rhinology. Computational rhinology has already contributed significantly to advancing our understanding of the nasal function, including airflow patterns, mucosal cooling, particle deposition, and drug delivery, and is foreseen as a crucial element in, e.g., the development of virtual surgery as a clinical, patient-specific decision support tool. The current paper delves into the field of computational rhinology from a nasal airflow perspective, highlighting the use of computational fluid dynamics to enhance diagnostics and treatment of breathing disorders. This paper consists of three distinct parts—an introduction to and review of the field of computational rhinology, a review of the published literature on in vitro and in silico studies of nasal airflow, and the presentation and analysis of previously unpublished high-fidelity CFD simulation data of in silico rhinomanometry. While the two first parts of this paper summarize the current status and challenges in the application of computational tools in rhinology, the last part addresses the gross disagreement commonly observed when comparing in silico and in vivo rhinomanometry results. It is concluded that this discrepancy cannot readily be explained by CFD model deficiencies caused by poor choice of turbulence model, insufficient spatial or temporal resolution, or neglecting transient effects. Hence, alternative explanations such as nasal cavity compliance or drag effects due to nasal hair should be investigated.publishedVersio
Modellering av energisystemet på Mære. Mulige investeringer som kan øke selvforsyningsgraden av energi
Get PDFMære landbruksskole ligger i Steinkjer kommune i Trøndelag og er eid av Trøndelag fylkeskommune. Det er en videregående skole som tilbyr utdanning innen naturbruk, og samtidig driftes et skolegårdsbruk. Mære landbruksskole har et mål om å bli en nullutslippsgård, og viktige elementer er reduksjon i energibruk og egenproduksjon av fornybar energi. I denne studien har vi sett på energisystemet på Mære og vurdert potensielle investeringer som kan gjøre landbruksskolen mer selvforsynt med strøm.
Kategoriene av tiltak som er vurdert, er ENØK-tiltak, solstrømproduksjon og batteri, samt biogassanlegg. Studien viser at man kan øke selvforsyningsgraden for strøm og samtidig redusere årlige kostnader. Laveste totale årskostnader oppnås for scenariet der man kombinerer ENØK-tiltak, ny solstrømproduksjon (246 MWh/år økning) og biogassanlegg. Dette scenariet reduserer behovet for strøm fra nettet med 30 % og topplasten med 24 % sammenlignet med å ikke gjøre noen nye investeringer. En betydelig kostnadsreduksjon oppnås også for scenariet med kun ENØK-tiltak, hvor årlig energibehov og topplast reduseres med hhv. 15 og 16 %. Investering i kun biogassanlegg eller kun solstrømproduksjon vil redusere både årlig behov for strøm fra nettet og topplast uten at man får en økning i totale årlige kostnader.
Å redusere effekttoppene vil ha innflytelse på energikostnadene for Mære landbruksskole gjennom effektleddet for strøm. Redusert topplast gir også en samfunnsøkonomisk gevinst fordi det avlaster kraftnettet, både i forsyning inn til Mære og i omkringliggende kraftforsyning. Kraftnettet må dimensjoneres etter den høyeste etterspørselen som kan oppstå, og på landsbasis har maksimalt effektuttak økt betydelig de siste årene. Reduksjon av effekttoppene hos forbrukerne kan derfor bidra til økt kapasitet og fleksibilitet i nettet.
Denne studien vil gi Mære landbruksskole og Trøndelag fylkeskommune en pekepinn på hvilke investeringer som kan være lønnsomme, og hvordan disse vil bidra til å redusere behovet for importert strøm og således være steg på veien til å realisere nullutslippsgården. Mæremiljøet er allerede en god innovasjonsarena for FoU-miljøer og ulike leverandører inn mot landbrukssektoren, og erfaringer som høstes her vil kunne bidra til økt bærekraft innen en viktig sektor.publishedVersio
The 11th Society of Petroleum Engineers Comparative Solution Project: Problem Definition
Get PDFThis article contains the description of, and call for participation in, the 11th Society of Petroleum Engineers Comparative Solution Project (the 11th SPE CSP, https://spe.org/csp). It is motivated by the simulation challenges associated with CO2 storage operations in geological settings of realistic complexity. The 11th SPE CSP contains three versions: Version 11A is a 2D geometry at the laboratory scale, inspired by a recent CO2 storage forecasting and validation study. For Version 11B, the 2D geometry and operational conditions from 11A are rescaled to field conditions characteristic of the Norwegian Continental Shelf. Finally, for Version 11C, the geometry of Version 11B is extruded to a full 3D field model. The CSP has a two-year timeline, being launched at the 2023 SPE Reservoir Simulation Conference and culminating at the 2025 SPE Reservoir Simulation Conference. A community effort is run in parallel to develop utility scripts and input files for common simulators to lower the threshold of participation; see the link to supplementary material on the CSP website. At the time of writing, complete input decks for one simulator are already ready for all three versions.publishedVersio
Life cycle inventory library for embodied emissions in ventilation components
Get PDFTechnical components are generally poorly described in environmental assessments of buildings. In this work, an extensive library of life cycle inventories for generic ventilation components and dimensions have been developed and documented. Components are described as unit processes and can be used to improve the understanding and coverage of ventilation systems in environmental assessment of buildings, and as potential building blocks for optimization of ventilation system design with minimum life cycle emissions. The ventilation components library has been tested on a modern and energy-efficient office building. Results show that more than 78 % of the climate footprint was covered directly by the library, while the main part of the remaining footprint was associated with non-standardized and building specific components. The coverage was even higher for other environmental impact categories. To assess the coverage of the library and estimate the full impacts for a complete ventilation system, inventories were developed also for the building specific components. Results from this showed an estimated total weight of 6.84 kg/m2 floor area, and a climate footprint of 22.7 kg CO2-eq./m2 floor area. Air handling units and circular ductwork were by far the top contributors with a combined 55 % of climate emissions, with roughly equal shares from both.publishedVersio
A novel framework for assessing the smartness and the smart readiness level in highly electrified non-residential buildings: A Norwegian case study
Get PDFThis work presents a new operational framework to measure the smartness and smart readiness of highly electrified buildings. The framework seeks to enhance legacy systems and controls of existing buildings and establish minimum criteria for future constructions to ensure they interact effectively with users and the grid, aiming for a clean energy transition. To this end, we develop two modified complementary assessments, one based on the method indicated by the Smart Readiness Indicator (SRI), proposed by the European Union (EU), and the other following the Smart by Powerhouse scheme, introduced by a Norwegian consortium of stakeholders focused on developing future proof climate buildings. The proposed structure is implemented in ten non-residential buildings in Norway with different energy systems, typologies, and construction dates. The results of this study demonstrate that energy flexibility quantification plays a crucial role in correctly implementing the framework in highly electrified buildings. Therefore, the dynamic impact of having Electric Vehicle Charging (EVC) and other electrical-dependent loads must be considered in the assessment. With the proposed modifications, the EVC weight in the flexibility score now varies from 24.0 to 43.6%, up from the original 5%. Overall, the pilot buildings have a smart readiness level between 21.6% and 31.7%, with mostly automated smartness levels. Nevertheless, the study also emphasizes the need to differentiate current HVAC (Heating, Ventilation, and Air Conditioning) technologies and their efficiencies.publishedVersio