Luleå University of Technology Publications
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Genomic, Proteomic, and Biochemical Study of Pleurotus pulmonarius Secretome and Its Role in Biomass Saccharification
No full textPleurotus species include edible mushrooms that grow on a range of lignocellulosic substrates by secreting hydrolytic and oxidative enzymes. This flexibility offers opportunities to valorize agro-industrial residues for sustainable production of food and biomaterials. In this study, we analyzed the genome of Pleurotus pulmonarius and its biocatalytic potential for lignocellulose saccharification using proteomics and biochemical assays. The fungus was cultivated on beechwood, corn stover, and xylose. Beechwood induced the richest secretome with abundant oxidases. The corn stover secretome had fewer proteins but was focused on carbohydrate-acting enzymes, with abundant polysaccharide-degrading and accessory enzymes. Despite lower enzyme diversity, corn stover secretome achieved higher lignocellulose saccharification, further improved by oxidoreductase inhibition. Supplementing an industrial cellulase cocktail with P. pulmonarius corn stover secretomes enhanced sugar release by 40%. These findings highlight the dynamic enzymatic response of P. pulmonarius to lignocellulosic substrates and its potential in biomass valorization and the design of enzymatic cocktails. Validerad;2025;Nivå 2;2025-11-21 (u8);Full text license: CC BY</p
Effect of Zinc Oxide Concentrations on the Reactivity of Iron Silicate Slags as a Supplementary Cementitious Material
No full textPyrometallurgical extraction of copper generates an average of 2.2–3.0 tons of slag per ton of copper. With rising copper demand, future increases in slag volumes are expected, making the exploration of sustainable slag utilization essential. There are several applications for iron silicate slag. However, from a global perspective, a large amount of slag still ends up in landfills due to environmental concerns related to the potential weathering of metals present in the slag. This occurs despite results indicating that an improved slag-cleaning process makes iron silicate slag suitable for external applications. One potential application is utilizing iron silicate slag in the cement industry as a supplementary cementitious material (SCM). Given the wide range of ZnO content found in iron silicate slags worldwide, along with previous studies on Portland cement indicating that ZnO negatively affects the cement’s hydration process, there is a clear need for a structural investigation into how ZnO impacts the reactivity of iron silicate slag. This understanding is important for optimizing the use of iron silicate slag as an SCM. Therefore, this study covers a systematic investigation of the effect of ZnO on the inherent reactivity of iron silicate slag. Synthetic slags in the FeO–SiO2–CaO–Al2O3–MgO–ZnO system, with systematic variations in ZnO concentrations between 0 and 14.6 wt.%, were produced on a laboratory scale using water granulation. Results from isothermal calorimeter testing indicate that increasing ZnO concentrations decrease the slag’s inherent reactivity. These findings highlight the necessity of implementing a slag-cleaning process that minimizes zinc concentrations to facilitate the successful use of iron silicate slag as an SCM.Full text locense: CC BY</p
Harnessing germanium from industrial residues and electronic waste for a sustainable energy future
No full textTraditionally, germanium has been a critical dopant in the silica core of fiber optics, facilitating high-speed internet and data transfer, and functions as a semiconductor in N-type diodes. Over the past decade, its importance has greatly expanded to multi-junction solar cells, where it serves as a substrate, providing a foundation for other semiconductor layers. Despite rising demands from renewable energy and semiconductor industries, germanium has no primary ores and is found only as a companion element with others. It is primarily sourced as a by-product from industrial residues like zinc refinery residues (ZRR) and coal burnt fly-ash (CFA), with concentrations ranging between 0.04–0.5% and 0.05–1.7%, respectively. Given the scarcity of germanium, its recovery through recycling of electronic waste is also gaining interest. However, the recovery process from both primary and secondary sources is complex, involving several key steps to ensure efficient extraction. Therefore, a comprehensive understanding of these processes, along with thermodynamic strategies applied to different materials, is essential. Consequently, this review covers germanium recovery from major primary and secondary resources, involving leaching, solvent extraction, ion exchange, and precipitation methods, with a focus on the underlying thermodynamics. Additionally, the environmental impacts of different extraction schemes are assessed using life-cycle analysis, revealing the global warming potential (GWP) of 852 kg CO2-eq for ZRR and 698 kg CO2-eq for CFA. In contrast, recycled germanium exhibits a much lower GWP of 163 kg CO2-eq, highlighting the importance of recycling efforts in advancing Sustainable Development Goals 7, 12, and 13.Validerad;2025;Nivå 2;2025-11-27 (u4);Full text license: CC BY</p
Configuring innovation ecosystem capabilities for scaling digital innovation in construction
No full textDigital transformation in construction is often hindered by fragmented innovation processes and building project-centric technology trials. This study investigates how construction firms can configure and coordinate organizational capabilities to scale digital innovations from isolated Proof of Concept (POC) tests to firm-wide transformation. Drawing on innovation ecosystem theory, construction management, technology and innovation management on innovation uptake, the article presents findings from a qualitative case study of a sensor-based POC in a Swedish building project. Data were collected through eight in-depth interviews and 26 h of participant observation. The analysis identifies four interconnected sets of capabilities across ecosystem, project, and firm interfaces that support scaling, including configurations for value creation, alignment of value propositions, digital maturity, and cross-project learning for value capture. The study contributes to construction management literature by introducing a model of analysis for ecosystem-driven transformation and highlighting the role of digital brokers in aligning actors and accelerating capability-enhanced scale-up. Practical implications include the need for strategic coordination, cross-project learning, and capability configuration across organizational interfaces to overcome structural barriers to digitalization. Full text license: CC BY</p
Modeling and assessment of waveform distortion interaction at the railway grid side in low-frequency electrification systems
No full textThis work addresses the imbalance in the literature regarding the modeling of waveform distortion resonance and propagation in low-frequency railway electrification systems, focusing on the Swedish Electric Railway Power Supply (ERPS). A framework is proposed for modeling synchronous components of waveform distortion up to 25 kHz, incorporating local interactions between traction converter stations (TCSs) and rolling stock. The nodal admittance matrix is developed for an autotransformer-fed circuit with three railway sections and four TCSs. Rolling stock is represented through a measurement-based Norton model capturing high-order components and probabilistic harmonic emissions. Monte Carlo (MC) simulations assess resonance and propagation uncertainties under variable operating conditions. Results reveal key influences of railway section lengths, filters, and stochastic emission models on impedance characteristics, offering ERPS tools for future assessment.Validerad;2025;Nivå 2;2025-11-03 (u4);Full text license: CC BY;This article has previously appeared as a manuscript in a thesis.</p
Motivational Implications of Automation at Work: A Large-Scale Survey Study Among Social Workers in Sweden
No full textAutomation of work tasks presents both opportunities and challenges for social workers, whose roles are heavily reliant on human interaction and emotional engagement. In this study we investigated motivational implications of automation in the social services sector through the lens of self-determination theory. Using data from a large-scale survey of 6309 social workers in Sweden, we examined differences in work motivation, job satisfaction, and turnover intentions between those working with and without automation. Automation was associated with lower levels of self-determined motivation and job satisfaction, and higher turnover intentions. Mediation analyses revealed that automation negatively predicted job satisfaction and positively predicted turnover intentions through self-determined motivation. Although automation may enhance efficiency and alleviate administrative burdens, its current implementation seems to undermine social workers’ self-determined motivation. Our findings underscore the importance of designing automation that supports employees’ self-determined motivation, and we offer practical recommendations for implementing automation while supporting social workers’ motivation. Full text: CC BY License;</p
Optimisation of Muon Portals for Border Controls Using TomOpt
No full textTomOpt is a software package designed to optimize the geometric configuration and specifications of detectors intended for tomography using cosmic-ray muon scattering. Differentiable programming is utilized in this software to model muon interactions with detectors and scanned volumes, infer volume properties, and perform loss minimization in an optimization cycle. In this paper, we introduce the implementation in TomOpt of a case study related to cargo scanning at border control points, such as cargo harbors and truck inspection stations.Godkänd;2025;Nivå 0;2025-08-18 (u1);Full text license: CC BY 4.0;Funder: Fonds de la Recherche Scientifique - FNRS (grants No. T.0099.19 and J.0070.21); Spanish Ministry of Science and Innovation MCIN/AEI/10.13039/501100011033 (project No. RYC2021-033305-I); European Union NextGenerationEU/PRTR</p
Optimisation of areca nut husk-derived cellulose nanofibers for enhancing the mechanical properties of epoxy composites using response surface methodology
No full textAreca nut husk, a widely available yet underutilised agro-waste, is explored in this study as a novel and sustainable source of cellulose nanofibers (CNFs), addressing both environmental concerns and the growing demand for bio-based reinforcements in polymer composites. CNFs were extracted using alkali and bleaching treatments followed by ultrasonication, yielding fibres with a mean diameter of 35.84 nm. Epoxy composites were fabricated with CNF loadings ranging from 0.1 to 1.0 wt%, while key processing parameters, including mixing time (10–30 min) and curing temperature (60–100 °C), were optimised using Response Surface Methodology (RSM) based on a Box–Behnken Design. The developed regression models exhibited high predictive accuracy, with R2 values of 99.63% for tensile strength and 99.80% for flexural strength. Analysis of variance (ANOVA) identified CNF content as the most influential factor (F = 934.48 and 1646.71 for tensile and flexural strength, respectively), followed by mixing time and curing temperature. Optimised conditions of approximately 1.5 wt% CNF, 22 min mixing, and 80 °C curing yielded experimentally validated tensile and flexural strengths of 61.88 MPa and 74.36 MPa, respectively, deviating by only 5.27% and 2.76% from model predictions. These results confirm the effectiveness of process-optimised CNF incorporation in enhancing mechanical performance and highlight the potential of areca nut husk as a viable, high-performance bio-reinforcement for next-generation green composites.Validerad;2025;Nivå 2;2025-08-06 (u5);Full text license: CC BY 4.0;Funder: Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia (PNURSP2025R140); King Khalid University (RGP2/424/46);</p
Upcycled PET-Derived Carbon Foam Functionalized with Cu3SbS4–Sb2S3 Heterostructures for Efficient Interfacial Solar Desalination
No full textSolar desalination is an emerging technique to produce fresh water utilizing renewable solar energy. However, the engineering of efficient photothermal material is a significant obstacle. In the present study, a carbon foam is synthesized from the upcycling of waste PET and hydrothermally functionalized with a heterostructure composed of Cu3SbS4 and Sb2S3. Material characterizations demonstrated the successful decoration of nanochannels on graphitic carbon foam (CF). The analysis of the optical properties in the UV/Vis-NIR spectral range demonstrated excellent absorption properties of 96% for Cu3SbS4-Sb2S3/CF compared to Sb2S3/CF (48%) and CF (68%) in near-IR. Photothermal desalination results reveal the evaporation rate of 2.82 kg m−2 h−1 for Cu3SbS4-Sb2S3/CF compared to 1.4 kg m−2 h−1 for Sb2S3/CF and 1.58 kg m−2 h−1 for CF, with 99% salt removal in condensed water. The formation of the composite leads to a high surface temperature and enhanced evaporation rate. The contact angle analysis confirmed the hydrophilic nature of the material that plays a crucial role in the solar desalination process. These findings elucidate the effective photothermal performance achieved through chalcogenide heterostructure engineering supported on upcycled carbon foam derived from waste PET, demonstrating a practical application aligned with circular economy principles in solar desalination. Validerad;2025;Nivå 2;2025-11-06 (u8);Funder: European Union NextGenerationEU (PRIN 2022); European Union NextGenerationEU (CUP: H53D23003840001);Full text license: CC BY</p
Wellbeing Among Police Personnel Investigating Online Child Sexual Abuse: A Scoping Review
No full textOnline child sexual abuse (CSA) crimes have increased significantly in recent years, reflecting broader access to the internet and the global proliferation of CSA content. In response, national police forces have established specialized investigative teams. Notably, repeated exposure to CSA material has been identified as a significant stressor for police personnel, potentially increasing the risk of secondary traumatic stress and burnout. Therefore, understanding and addressing the impact of continuous CSA exposure on personnel’s wellbeing is essential within this area of digital policing. This scoping review aims to synthesize and report the existing empirical research on the wellbeing of police personnel involved in online CSA investigations. Following established guidelines, we searched four electronic databases—Scopus, Web of Science (Clarivate), PsycINFO, and SocIndex—for articles published between 2000 and 2024. We also conducted reference mining of the included studies. In total, 33 articles met the inclusion criteria: empirical studies published in English, in peer-reviewed journals, and focused on the wellbeing of personnel investigating online CSA. Findings reveal substantial variation in reported wellbeing. Individual coping strategies, as well as organizational resources and support, play a critical role in how personnel manage the demands of this work. Based on these insights, we recommend that online CSA police units implement clear and proactive strategies to safeguard personnel’s wellbeing.Full text license: CC BY</p