Luleå University of Technology Publications
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How circular are large corporations? Evidence from a large-scale survey with senior leaders
No full textThe circular economy has been promoted as a way for corporations to radically improve their resource efficiency and effectiveness by narrowing, slowing, closing and regenerating resource flows. However, the degree of implementation of these circular strategies across different geographies and industries is little understood. We conducted a large-scale survey with senior leaders in large corporations focused on the implementation of these circular strategies in different corporate functions. We find that the close the loop strategy is most implemented overall, followed by narrowing and slowing the loop. Regeneration is the least implemented. In companies’ own operations, narrow the loop strategies were far ahead of any other strategies. In the supply chain function, narrow the loop strategies start earliest. In the products and services function, close the loop strategies have generally been prioritised. This study shows progress in circular implementation in corporations but also important gaps to move beyond low-hanging fruits.Validerad;2025;Nivå 2;2025-02-26 (u5);Full text license: CC BY 4.0;</p
Influence of pretreatments on the surface charge of anode and cathode materials in spent lithium-ion batteries - a key point for recycling
No full textThe flotation process for separating anode and cathode materials (blackmass) is a critical step in recycling lithium-ion batteries (LIBs), particularly before the extraction of lithium-bearing materials. Surface electric charge, measured via zeta potential, plays a pivotal role in the flotation separation of these electrode materials. The pH, roasting temperature, thermal treatment duration, and bubbles' presence can significantly influence these materials' surface properties. However, a comprehensive investigation addressing the combined effects of these factors on the zeta potential of electrode active materials is still lacking. This study aims to bridge this gap by systematically exploring the effects of pH (4.5, 7, and 10.5), roasting temperatures (0–500 °C), varied thermal treatment times (1 to 2 h), and the presence or absence of bubbles (nano and microbubbles) on the zeta potential of both anode and cathode materials. The study also examines the impact of conditioning with n-dodecane, a typical flotation collector. While zeta potential is largely pH-dependent, roasting temperature significantly influences surface charge, whereas thermal treatment duration has a minimal effect. Notably, the most considerable zeta potential difference (28.3 mV) between the anode (-18.63 mV) and cathode (9.67 mV) surfaces occurred in the absence of both collector and bubbles, at pH 7, 500 °C, and a thermal treatment time of 2 h. Under conditioning involving bubbles and collector, the highest difference observed was 2.21 mV at pH 7, 250 °C, and 1 h of thermal treatment. These findings contribute to a deeper understanding of surface charge behavior in LIB recycling processes, with implications for improving flotation separation efficiency through surface science and engineering.Validerad;2025;Nivå 1;2025-03-03 (u2);Funder National Natural Science Foundation of China (NSFC), (grants No 52350410452 and No 52104273); Jiangsu Provincial Key R&D Plan (Social Development), (BE2022717);Full text: CC BY license;</p
How language proficiency and age of acquisition affect executive control in bilinguals: continuous versus dichotomous analysis approaches
No full textResearchers have argued that grouping heterogeneous linguistic profiles under a dichotomous condition might mask the cognitive effects of bilingualism. The current study used two different analysis approaches (i.e., continuous versus dichotomous) to examine inhibitory control in a sample of 239 young adult bilinguals. Dividing the sample into dichotomous groups based on L2 proficiency (i.e., high-proficient versus low-proficient) and L2 AoA (i.e., early versus late) did not lead to reliable group differences in any of the measurements used. However, the use of a continuous measure revealed that higher L2 proficiency predicted better visual inhibition and earlier L2 AoA was associated with better auditory inhibition. Furthermore, the observed differences were limited to tasks involving stimulus–stimulus competition, but not stimulus–response competition. These findings shed new light on the importance of conceptualising bilingualism as a continuous measure rather than a dichotomous measure and previous research on bilingual performance in different cognitive tasks.Validerad;2025;Nivå 2;2025-08-14 (u5);Funder: National Social ScienceFund of China (22CYY016); Independent Innovation Fund of Huazhong University of Science and Technology (2022WKYXQN005); School of Philosophy, Psychology & Language Sciences (PPLS);Full text license: CC BY</p
Discharge distribution in a multi-outlet spillway with varying adverse conditions
No full textHydropower and dam structures worldwide are facing evolving requirements due to changes in climate, better methods for flood estimates, combined with the needs of surrounding interests. Improved understanding of the hydraulic behavior of spillways, and the approach flow leading up to them, is important for evaluation of existing spillways and considering potential redesigns. There is limited research on the distribution of flow across a multiple outlet spillway, therefore a purpose built experimental setup is utilized to examine the impact of various geometrical changes on the flow distribution across a spillway with three outlets. The maximum difference measured between the different outlets were as much as 10%. While small changes to abutment and pier corners were found to reduce total discharge capacity up to 8%, with increased discharge and overflow height causing greater reduction in the capacity of the spillway. To further investigate the flow behavior leading up to the spillway outlets, ADV measurements were conducted to capture flow velocities. The measured flow cross sections indicate a stable flow field leading away from the inlet, stagnation zones and recirculation zones leading up to the spillway, with minor variations occurring for increasing inlet flow rates.Validerad;2025;Nivå 2;2025-03-10 (u4);Fulltext license: CC BY</p
On the Right Path to Circularity or Running Around in Circles? A Fresh Perspective on Circular Business Model Barriers
No full textThe literature on circular business models (CBMs) has generated barrier categories and taxonomies but provides an incomplete understanding of how firms develop and scale CBMs in practice. We challenge prior literature by relating barriers directly to the CBM dimensions of value creation, value delivery, and value capture. Following this approach, we analyze the Swedish manufacturing industry using qualitative content analysis and arrive at three key contributions. First, there is a distinct set of barriers affecting value creation, value delivery, and value capture. Second, the barriers are underpinned by a unique set of problems, many of which are nondecomposable. Third, most barriers inhibit the scaling of CBMs rather than their initial development. Altogether, this has major implications for understanding the nature of CBMs, productively addressing CBM barriers and problems, and scaling CBMs. We conceptualize these insights into a framework with implications for both the CBM literature and for managers innovating CBMs.Validerad;2025;Nivå 2;2025-05-23 (u2);Full text license: CC BY-NC</p
Flexible Production of Spherical Powders of Ti-V-Zr-Nb-Mo-Hf-Ta-W Refractory High-Entropy Alloys by Plasma-Assisted Centrifugal Atomization
No full textIn this work, the capabilities of plasma-assisted centrifugal atomization for the fabrication of spherical powders of Ti-V-Zr-Nb-Mo-Hf-Ta-W refractory high-entropy alloys (R-HEAs) are thoroughly studied. Atomization in the transient regime by direct droplet formation is investigated through batch processing by simultaneous melting, alloying, and atomization from a blend of intimately mixed elemental powders pre-packed in the atomization crucible. In this processing approach, selective depletion of the heaviest elements is attributed to solid-solid centrifugal separation during the early stages of melting by plasma arc. Conversely, atomization in the steady-state regime by ligament formation is investigated through continuous processing by plasma-assisted centrifugal re-atomization of pre-alloyed feedstock fed into the rotating crucible from the top. In this case, diffusion-driven elemental redistribution in the liquid state occurs only within a thin molten metal film, leading to reduced selective depletion of the heaviest elements. The effect of the rotational speed of the atomizing unit on the particle sizes, the chemical composition, the crystal structure, and the microstructure of the atomized powders is investigated. The use of both inert (Ar) and reactive (Ar+N2) plasma carrier gases is considered for the in situ, one-step fabrication of purely metallic and metal-ceramic composite powders, respectively. Validerad;2025;Nivå 2;2025-06-25 (u5);Full text license: CC BY;This article has previously appeared as a manuscript in a thesis.</p
Quality 2030 : quality management for the future
No full textQuality management (QM) has shown an impressive ability to update and evolve. The purpose of this paper is to highlight themes that have been identified as vital and important for research projects within QM during the coming decade. The paper is also an attempt to initiate research for the emerging 2030 agenda for QM, here referred to as ‘Quality 2030’. This article is based on extensive data gathered during a workshop process conducted in two main steps: (1) a collaborative brainstorming workshop with 22 researchers and practitioners (spring 2019) and (2) an appreciative inquiry summit with 20 researchers and practitioners (autumn 2019). The process produced five collectively elaborated and designed future research themes for QM: (a) systems perspectives applied, (b) stability in change, (c) models for smart self-organising, (d) integrating sustainable development, and (e) higher purpose as QM booster. The process also identified a positive core of QM, defined as core values and aspects in the field and practice that need to be preserved and nurtured in the future.Validerad;2025;Nivå 1;2025-03-17 (u4);Fulltext license: CC BY-NC-ND</p
Metaverse in industrial contexts - a comprehensive review
No full textThis paper explores the potential of Metaverse technology in industrial Asset Management (AM). By integrating AI and digital technologies, the Metaverse can enhance Human-System-Interaction (HSI) and optimise AM processes. However, implementing a Metaverse in industrial contexts faces challenges, particularly in visualising physical and virtual assets. This paper conducts a systematic review to address these challenges and identify potential solutions. The findings reveal that while the necessary technologies are available, their widespread adoption in industrial AM is limited. The paper presents a comprehensive overview of research themes related to Metaverse applications in industrial contexts, highlighting the evolving landscape and potential benefits. Ultimately, this research aims to contribute to the advancement of Metaverse technology in industrial AM by providing insights into its development, implementation, and challenges along with an Industrial Metaverse Framework. An example of applying the Metaverse concept in the railway sector has been presented and validated using railway digital assets available within the eMaintenance LAB. The practical implications of this work are expected to result in increased efficiency and effectiveness in the operation and maintenance procedures across various industrial sectors.Validerad;2025;Nivå 1;2025-02-20 (u8);Full text license: CC BY</p
The Effectiveness of Tele-rehabilitation for Older Adults : A Literature Review
No full text Bakgrund: Världens åldrande befolkning ökar kraven på hälso- och sjukvården. Telerehabilitering erbjuder ett alternativ till traditionell rehabilitering. Telerehabilitering kan öka tillgänglighet och flexibilitet, särskilt för äldre som har svårt att ta sig till en vanlig rehabiliteringsmottagning. Utmaningar inkluderar tekniska problem och brist på teknisk kunskap. Effektiviteten av telerehabilitering för äldre undersöks, med fokus på hälsoresultat och funktionsförmåga. Tidigare studier har visat lovande resultat för telerehabilitering, inklusive förbättrad fysisk funktion och livskvalitet. Syftet med denna litteraturstudie är att systematiskt granska befintlig forskning för att utvärdera telerehabilitering effektivitet hos äldre personer. Metod:Systematisk litteraturöversikt genomförd i PubMed och PEDro för att utvärdera telerehabilitering för äldre (60+). Sökstrategier baserades på PICO: Population (äldre), Intervention (telerehabilitering), Control (jämförelsegrupp), Outcome (fysisk aktivitet och funktion, livskvalitet). Randomiserade kontrollerade studier (RCT) inkluderades. Urvalsprocessen följde PRISMA 2020. Kvalitetsgranskningen genomfördes med PEDro-skalan. Tio studier inkluderades Resultat: I studien inkluderades tio randomiserade kontrollerade studier publicerade mellan 2015 och 2024, med totalt 808 äldre deltagare. Kvalitetsgranskningen med PEDro-skalan visade att åtta studier hade god kvalitet och två medelmåttiga. Telerehabilitering visade positiva effekter jämfört med traditionell rehabilitering och andra kontrollgrupper. Signifikanta förbättringar observerades i fysisk funktion, balans, gångförmåga och muskelstyrka. Flera studier rapporterade signifikanta förbättringar i hälsorelaterad livskvalitet. Kombinationen av synkron och asynkron kommunikation ansågs vara effektiv för personcentrerad rehabilitering. Telerehabilitering framstod som ett lovande alternativ för att förbättra hälsa och välbefinnande hos äldre Konklusion: Telerehabilitering har potential att förbättra hälsan och funktionen hos äldre personer.. Trots heterogeniteten i studierna och vissa metodologiska begränsningar visar studierna att det kan förbättra fysisk aktivitet, livskvalitet och minska fallrisk. Mer standardiserad forskning behövs för att ge tydligare råd till vården. Background: The globally aging population is increasing demands on healthcare systems. Telerehabilitation offers an alternative to traditional rehabilitation, potentially enhancing accessibility and flexibility, especially for older adults with mobility limitations. Challenges include technical issues and a lack of digital literacy. The efficacy of Telerehabilitation for older adults is being explored, focusing on health outcomes and functional abilities. Previous studies have demonstrated promising results, including improvements in physical function and quality of life. This systematic review aimed to examine existing research and evaluate the effectiveness of telerehabilitation interventions in older adults. Methods: A systematic literature review was conducted in PubMed and PEDro to assess the effectiveness of TR in older adults (60+). Search strategies were based on the PICO framework: Population (older adults), Intervention Telerehabilitation, Control (comparison group), and Outcome (physical activity and function, quality of life). Randomized controlled trials (RCTs) were included. The selection process adhered to the PRISMA 2020 guidelines. Quality assessment was performed using the PEDro scale. Ten studies were included. Results: Ten RCTs published between 2015 and 2024, involving a total of 808 older participants, were included. Quality assessment using the PEDro scale indicated that eight studies were of good quality and two were of moderate quality. Overall, telerehabilitation demonstrated positive effects compared to traditional rehabilitation and control groups. Significant improvements were observed in physical function, balance, gait, and muscle strength. Several studies reported significant enhancements in health-related quality of life. The combination of synchronous and asynchronous communication was deemed effective for personalized rehabilitation. Telerehabilitation emerged as a promising approach to improve health and well-being in older adults. Conclusion: Telerehabilitation has the potential to enhance health and function in older adults. Despite the heterogeneity of the included studies and some methodological limitations, the results suggest that Telerehabilitation can improve physical activity, quality of life, and reduce fall risk. Further standardized research is needed to provide clearer recommendations for clinical practice
Modeling Transport Properties of Ionic Liquids based on ePC-SAFT
No full textIonic liquids (ILs) are promising fluidic materials due to their unique physicochemical properties, driving extensive research for diverse applications. Key properties, including thermodynamic properties (e.g., density and solubility) and transport properties (e.g., viscosity and self-diffusion coefficient (SDC)), play a crucial role in developing IL-based technologies. These properties are typically characterized through experiments and theoretical modeling. However, given the time-consuming and costly nature of experiments, developing accurate theoretical models is essential for optimizing IL-based applications. Thermodynamic models for various fluids, including ILs, are well-established, with the ion-specific electrolyte perturbed-chain statistical associating fluid theory (ePC-SAFT) effectively modeling the thermodynamic properties of ILs. In contrast, transport property models depend largely on experimental data, leading to separate modeling of viscosity and SDC. For viscosity, ePC-SAFT has coupled with free volume theory (ePC-SAFT-FVT), but inconsistencies arise between ion- and molecular-based frameworks in the two models. Meanwhile, theoretical SDC models are scarce and have yet to be applied to ILs. Traditionally, thermodynamic and transport property models use distinct molecular parameters, though, in principle, these parameters should be independent of specific properties. This suggests the feasibility of a universal approach to determining transport properties based on molecular parameters of thermodynamic models. Additionally, as both viscosity and SDC characterize molecular motion, it remains unclear whether they can be simultaneously modeled for ILs. This thesis aimed to propose a universal approach to modeling thermodynamic and transport properties of ILs, where a predictive SDC model and an ion-specific ePC-SAFT-FVT for viscosity were developed, and the Einstein relation was employed to explore the simultaneous modeling of viscosity and SDC. In the first part, the SDC model for LJ fluids was extended to chain-like fluids using a correction function, with viscosity calculated via the Stokes-Einstein equation. By fitting SDC and viscosity data for 19 n-alkanes using molecular parameters from ePC-SAFT, a universal parameter set was obtained, achieving AARDs of 8.4% for SDC and 7.2% for viscosity. These parameters were used to predict the SDC and viscosity of long n-alkanes, branched alkanes, and cyclic compounds, with higher deviations for the latter two. The model was then extended to ILs, yielding AARDs of 39.4% for SDC and 30.1% for viscosity, with the performance considered acceptable due to using only three universal parameters. In the second part, an ion-specific ePC-SAFT-FVT model was developed to describe the viscosities of 72 ILs. The ion-based approach achieves an AARD of 8.7%, comparable to the molecular-based approach (AARD = 6.1%), while significantly reducing the number of adjustable parameters from 216 to 81. This enhances flexibility by enabling cation-anion parameter combinations for predictions. The model was extended to 19 IL mixtures, yielding an AARD of 9.1%, outperforming the molecular-based approach (AARD = 12.7%). These results show the ion-specific ePC-SAFT-FVT model effectively represents the viscosity of pure ILs and their mixtures. In the third part, the Einstein relation was combined with the ePC-SAFT-FVT model to describe the SDCs of ILs. Viscosity-derived FVT parameters were used to calculate the sum of ionic SDCs, requiring only one adjustable parameter. This parameter was either fitted for each IL (AARD = 8.1%) or predicted from the van der Waals volume (AARD = 10.3%). The predictive approach was also applied to calculate cationic and anionic SDCs using the total SDC and cationic transference number, yielding AARDs of 10.8% and 10.2%, respectively. These results show that, by utilizing viscosity-derived parameters, the ePC-SAFT-FVT model combined with Einstein relation effectively predicts the SDCs of ILs