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Implication of building renovation and renewable integration on the energy resilience in the Nordic climate: Techno-economic analysis using questionnaire-based thresholds
No full textAs climate change worsens energy insecurity, resilience to long-term blackouts in cold climates is increasingly critical. Blackouts can compromise indoor heating, leading to serious habitability, health, and survivability risks. Yet, most existing regulatory frameworks lack clear definitions of minimum habitability and survivability thresholds, and often under examine the role of demographic and social factors. This study presents a novel, integrated, human-centric method that combines a single-stage occupants survey—designed to assess energy resilience awareness, occupant-defined habitability and survivability thresholds, and key demographic factors—with a detailed building performance simulation model. Survey data was collected from 378 participants residing in a cold climate region (Finland) and is integrated with simulations of both old and renovated residential buildings, incorporating various passive and active energy systems, including building envelope, photovoltaics (PV), battery storage, and heat pumps. This interdisciplinary approach enables a comprehensive techno-economic analysis that effectively bridges social perceptions with technical assessments of energy resilience. Moreover, a new set of energy resilience indicators is proposed, specifically tailored for buildings in cold regions. These indicators form the basis of a color-based classification scheme used to visualize simulation outcomes and compare the resilience performances of the buildings. Survey results show that heating (i.e., habitability) is the top need in Finland, followed by electrical loads (i.e., survivability). Habitability thresholds differ by age, gender, location, and building type, ranging from 15 °C to 19 °C. Older buildings fail to meet these needs, especially for people over 50 years old. In passive conditions, dissatisfaction among older adults reaches 100 % and elevated psychological stress values. Renovations and renewable energy systems greatly improve resilience, reducing low heating risks and physiological stress—though at a 94 % cost increase. Dissatisfaction with habitability drops from 100 % to 1 %, and survivability improves from 0 % to 98 %. For adults aged 41–61+, dissatisfaction drops to 90 % (men) and 98 % (women) with building renovation, and with PV-battery systems, it falls to 0 % for both. This research offers a transferable, occupant-centered framework for assessing energy resilience, bridging technical, social, and economic dimensions to guide building adaptation in other cold climates and Nordic countries
Quasioptic, Calibrated, Full 2-port Measurements of Cryogenic Devices under Vacuum in the 220- 330 GHz Band
No full textA quasi-optical (QO) test bench was designed, simulated, and calibrated for characterizing all four S-parameters of devices in the 220–330 GHz (WR3.4) frequency range, from room temperature down to 4.8 K. Quasioptical calibration methods were applied to de-embed the impact of cryostat and optical elements on device under test measurements. The devices were measured through vacuum windows via focused beam radiation. A de-embedding method employing line-reflect-match (LRM) calibration was established to account for the effects of optical components and vacuum windows. Such a method does not require multiple line standards inside the cryostat and mechanical translation of quasioptics. System validation was performed with measurements of cryogenically cooled devices, such as bare silicon wafers and stainless-steel frequency-selective surface (FSS) bandpass filters, and superconducting bandpass FSS fabricated in niobium. A permittivity reduction of Si based on a 4 GHz resonance shift was observed concomitant with a drop in temperature from 296 to 4.8 K. The stainless steel FSS measurements revealed a relatively temperature invariant center frequency and return loss level of 263 GHz and 35 dB on average, respectively. Finally, a center frequency of 257 GHz was measured with the superconducting filters, with return loss improved by 11 dB on average at 4.8 K. To the best of our knowledge, this is the first reported attempt to scale LRM calibration to 330 GHz and use it to de-embed the impact of optics and cryostat from cryogenically cooled device S-parameters.</p
Implementing internal independent nuclear safety oversight – Insights from a Nordic empirical case study
Full text linkIndependent Nuclear Safety Oversight (INSO) is an internal organizational function that aims to provide nuclear licensee organizations an independent overview of their nuclear safety situation. This article provides an overview of the implementation and impact of INSO based on an empirical, qualitative case study in three Nordic nuclear power companies. INSO was perceived to contribute to nuclear safety by providing independent challenge of the line activities and decisions, advising and supporting the line organization and senior management, and providing an independent overview of nuclear safety. The implementation challenges were often managerial and included the underutilization of INSO recommendations by top management, lack of agreement between INSO and the line organization regarding INSO’s role, tasks, and results, and the unavailability of resources for conducting INSO activities. Our results also suggest that internal independence is not a black and white phenomenon and that there is no universally correct level of independence. Internal independence involves continuously and intelligently managing the tension between being isolated and losing perspective. The article concludes with recommendations for improving the effectiveness of INSO in global nuclear industry and suggests future development needs
Wood Reconfiguration Enables Broadband Blackbody in Large-Area, Modular, Optically Welded Carbon Constructs
No full textA broadband blackbody requires both perfect anti-reflective characteristics and effective light entrapment spanning wavelengths from the mid-infrared (MIR) to the ultraviolet (UV) range. This ideal combination has not been achieved in several artificial superblack systems or even in naturally occurring superblack structures. A broadband blackbody is created by carbonizing delignified wood infused with lignin particles (LPs), forming a reconfigured wood (cRW) system. The LPs enhance the dimensional fidelity of cRW and promote the development of sparse, highly aligned fibrillar microstructures, achieving super-absorbance levels spanning from the MIR to the UV wavelengths, reaching over 99.8% absorption. This performance is further amplified in large-area light traps constructed from tiled cRW, which are optically welded, modular and customizable in size and shape. The tiled cRW configuration effectively eliminates thermal ghost reflections and outperforms individual cRW units. This system is demonstrated as a perfect broadband blackbody, which can act as promising reference infrared radiator in IR thermography that benefit from precise sensor calibration. Altogether, this optically welded superabsorber trap introduces a wood-based solution for broadband blackbody materials, opening new opportunities across diverse applications.</p
Hydroxylamine grafting of periodate oxidized cellulose microfibrils and its impact on fibre adhesion
No full textIn this work, dialdehyde cellulose microfibrils (DA-CMFs) were reacted with O-substituted hydroxylamines, demonstrating an effective and versatile method for lateral functionalization of DA-CMFs using mild, aqueous reaction conditions. Depending on the conditions used, partial or complete substitution of the aldehydes could be achieved. The reaction was performed in the presence and absence of the reducing agent α-picoline borane (PB). DA-CMFs were reacted with O-(carboxymethyl) hydroxylamine (HAAA), and the adhesive properties of native and HAAA-conjugated DA-CMFs to fibres were studied. The adhesive properties were shown to depend on charge; while native DA-CMFs aggregate heavily in contact with the fibre surface, HAAA-conjugated DA-CMFs showed significantly improved adhesion. For a degree of substitution of 50% or higher, a sealed layer, without aggregates, could be observed using electron microscopy. Finally, a versatile protocol for co-insertion of HAAA (carboxylate) and aminooxy-PEG3-azide (hydroxylamine azide) was developed and demonstrated, with high yields of insertion. The modified DA-CMFs retained good adhesive properties to fibres, showing that the approach is general, and that the chemistry can be tuned depending on the target application
Finite-time Convergence Neural Network based Force-Motion Control for Unknown Surface with Orientation Compliance
No full textIn this paper, an adaptive force-motion control framework with orientation compliance is present for redundant manipulators in physical interaction with unknown surfaces. The proposed framework includes control task space definition and double-closed-loop control based on external force loop approach. Firstly, a specification matrix is designed merely through force feedback to ensure the control task space defined in orthogonal spaces. Then, an orientation compliance controller and a force-motion close-loop controller are constructed in the outer-loop control of external force feedback loop approach. Secondly, the output of outer-loop control task, along with boundary constraints and optimization indexes is formulated as a nolinear dynamic programming problem. Next a finite-time convergence neural network based inner-loop controller is proposed for this category of dynamic programming problem and its stability and convergence analysis are given. Simulations verify the convergence and effectiveness of the proposed framework. The real-world experiments show that the Mean Integral of the Absolute Error of the proposed control framework is reduced by 77.26% compared with constant impedance control.</p
Programming Education with LLMs and NPCs: A Dialogical Learning Framework for VS Code
No full textThe integration of Large Language Models (LLMs) holds significant promise for enhancing programming education by providing personalized, immediate feedback and fostering student engagement through adaptive learning. Existing research demonstrates that LLMs can offer meaningful learning support when designed with pedagogical considerations. However, challenges such as hallucinations in feedback and learners’ negative attitudes towards automated instructional solutions hinder broader adoption in educational contexts. Many existing solutions fail to promote critical thinking or address diverse learner needs. This paper proposes design of an interactive story-based environment for teaching programming languages, utilizing LLMs and automated assignment grading through a plug-in for Visual Studio Code (VSC). The goal is to provide contextual, pedagogically relevant tasks and feedback to students, employing Socratic questioning to encourage active participation and critical thinking. We adapt an existing VSC plug-in framework to support PHP and other common languages, designing middleware that enriches student prompts and redirects them to a custom-tuned curriculum-driven Swedish LLM. This architecture integrates meta-prompts based on pedagogical strategies into LLM interactions, employing a Socratic dialogue approach rather than providing direct answers. Anticipated outcomes include increased student engagement through storyline-based tasks and personalized feedback within the VSC environment, alongside better alignment of LLM interactions with pedagogical objectives. By presenting the underlying architecture of the prototype, we contribute to the use of generative AI in software engineering education. Our work highlights the potential of AI-powered tools in education to improve learning while addressing ethical considerations and ensuring need for thoughtful implementation to avoid amplifying biases or diminishing the role of teachers. Further studies are recommended to evaluate the impact of LLM interactions on student learning outcomes and to explore adaptability in real-life educational simulations
Intercomparison exercise of easy-to-measure and non-volatile difficult-to-measure analysis in homogenised high activity steel
No full textIntercomparison exercises (IE) are a way for laboratories to test their analytical performance. In case of difficult-to-measure (DTM) radionuclide analysis, participation in IEs are important due to the lack of reference materials. This paper reports the results from an IE focusing on non-volatile DTM analysis in homogenised high activity steel. The IE was carried out according to the ISO 13528 standard, in which the performances are assessed using z score. The z scores were generally acceptable. The experimental results were compared with activation calculation results showing wide range of compatibility.</p
Trip chain characteristics and situational factors influencing private car mode choices – A survey study in two Finnish urban areas
Full text linkHuman mobility is often characterized by trip chains with multiple destinations. However, the reasons behind mode choices have been mostly studied in single-purpose travel contexts. To address this gap, we examine how trip chain length, complexity (number of trip legs), and purposes are linked to situational factors influencing the decision to use a private car (i.e., context-dependent considerations that affect travel decisions, such as the need to save time, avoid bad weather, or be able to relax). Data was collected through a survey where participants described a recent private car trip chain, including items about trip purposes, the number of trips and trip legs, trip length, and the importance of various situational factors on mode choice decision. The survey was conducted in two major urban areas in Finland, yielding 731 valid responses. The results of a regression analysis show that all examined trip chain characteristics impact on the prevalence of different situational factors. Leisure being a trip purpose was associated with non-utilitarian factors influencing car use, and errands and commuting with both utilitarian and non-utilitarian factors. Trips involving errands appeared more habitual than trips for other purposes. Furthermore, complexity was not only associated with utilitarian factors, but also non-utilitarian. The findings suggest that trip chain complexity and purposes should be considered by practitioners and policymakers in sustainable mobility campaigns, passenger information systems that account for trip chain characteristics should be developed, and targeted interventions to reduce habitual car use, especially for errands, should be created
Anisotropic plasticity and damage of additively manufactured 316L stainless steel by multiscale approach
No full textStainless steel 316L produced by laser powder bed fusion (L-PBF) technique exhibits distinctly patterned microstructures due to directional rapid cooling of successive layers. Thus, its tensile properties are highly anisotropic depending on applied build strategies that often led to inferior performance compared to conventional 316L steel. In this work, a multiscale modeling approach was proposed for more precisely describing effects of complex printed microstructure characteristics on local and overall deformation behaviors of the steel. Micro-scale models incorporated grain morphologies and crystallographic textures developed in different melt pools. Hereby, the strain gradient crystal plasticity (CP) model was used to thoroughly reveal anisotropic stress-strain responses which were primarily driven by crystallographic features. Subsequently, a meso-scale model was employed to elucidate the heterogeneous deformation occurring at the melt pool boundaries, particularly in relation to the specified scanning patterns. Homogenized stress-strain properties of each meso-scale region were obtained from the micro-scale models in conjunction with the Hill48 yield criterion. Furthermore, the Hosford-Coulomb ductile damage model was defined on the meso-scale for representing crack initiations at crucial sites of the melt pools. The model showed that the grain configurations of 45°/0°/45° and −90°/0°/90° in melt pools strongly governed the anisotropic strain hardening behavior of printed samples. Local stress incompatibilities induced by grain and melt pool arrangements according to the defined scanning strategies resulted in different strain localizations and following damages. The approach can further serve as a framework for 3D printed material designs requiring more accurate microstructure-properties relationships.</p