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Exploring the Impact of Additive Manufacturing on Circular Economy in the Finnish Boatbuilding Industry: Insights from an R&D Lab
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As Industry 4.0 (I4.0) and circular economy (CE) gain increasing attention in both academic and industrial circles, this study investigates the role of I4.0 technologies, particularly additive manufacturing (AM), in advancing CE principles. Focusing on an R&D lab with experiences in the Finnish boatbuilding industry, the research explores how these technologies facilitate the adoption of CE practices. A thorough review of existing literature on AM and CE was conducted, followed by empirical research using qualitative methods and a case study approach. Data was gathered through interviews and supplemented by secondary sources. Thematic analysis revealed that AM positively impacts the CE in the boatbuilding industry, influencing product design, production processes, environmental sustainability, financial outcomes, and social factors. The study aligns with existing literature and offers practical recommendations for manufacturers, along with suggestions for future research.Abstract
As Industry 4.0 (I4.0) and circular economy (CE) gain increasing attention in both academic and industrial circles, this study investigates the role of I4.0 technologies, particularly additive manufacturing (AM), in advancing CE principles. Focusing on an R&D lab with experiences in the Finnish boatbuilding industry, the research explores how these technologies facilitate the adoption of CE practices. A thorough review of existing literature on AM and CE was conducted, followed by empirical research using qualitative methods and a case study approach. Data was gathered through interviews and supplemented by secondary sources. Thematic analysis revealed that AM positively impacts the CE in the boatbuilding industry, influencing product design, production processes, environmental sustainability, financial outcomes, and social factors. The study aligns with existing literature and offers practical recommendations for manufacturers, along with suggestions for future research
Designing Mo-based transition metal dichalcogenides for sustainable hydrogen production: Anionic substitution and DFT insight
No full textAbstract
Anionic substitution is an effective approach to optimize the catalytic activity of Mo based transition metal dichalcogenide (TMD)- MoS2 towards hydrogen evolution reaction (HER). By optimizing the S-to-Se ratio, materials with the ideal Gibbs free energy of hydrogen adsorption (ΔGH) values are synthesized (MoS2, MoS1.4Se0.6, MoS1.2Se0.8, MoSSe, MoSe2) and their HER performance is examined in 0.5 M H2SO4 solution. Density functional theory calculations of hydrogen adsorption energy on the surface of the electrocatalysts show that Se substitution facilitates electron transfer between the catalyst surface and the hydrogen donor, thereby lowering the additional potential required for water splitting, making MoS1.2Se0.8 the most favorable HER electrocatalyst with the lowest value of adsorption energy. Further enhancement in the electrocatalytic activity of mixed anion TMDs has been achieved by the incorporation of carbon nanotubes (CNTs). MoS1.2Se 0.8-CNT nanocomposite exhibits superior HER performance with an overpotential of 118 mV and a Tafel slope of 63 mV/decade as compared to MoS1.2Se0.8 sample owing to the synergetic effect from CNTs and MoS1.2Se0.8.Abstract
Anionic substitution is an effective approach to optimize the catalytic activity of Mo based transition metal dichalcogenide (TMD)- MoS2 towards hydrogen evolution reaction (HER). By optimizing the S-to-Se ratio, materials with the ideal Gibbs free energy of hydrogen adsorption (ΔGH) values are synthesized (MoS2, MoS1.4Se0.6, MoS1.2Se0.8, MoSSe, MoSe2) and their HER performance is examined in 0.5 M H2SO4 solution. Density functional theory calculations of hydrogen adsorption energy on the surface of the electrocatalysts show that Se substitution facilitates electron transfer between the catalyst surface and the hydrogen donor, thereby lowering the additional potential required for water splitting, making MoS1.2Se0.8 the most favorable HER electrocatalyst with the lowest value of adsorption energy. Further enhancement in the electrocatalytic activity of mixed anion TMDs has been achieved by the incorporation of carbon nanotubes (CNTs). MoS1.2Se 0.8-CNT nanocomposite exhibits superior HER performance with an overpotential of 118 mV and a Tafel slope of 63 mV/decade as compared to MoS1.2Se0.8 sample owing to the synergetic effect from CNTs and MoS1.2Se0.8
Adsorptive dye removal using surfactant-exfoliated montmorillonite/ crosslinked tetramethacrylate composites
No full textAbstract
This study introduces the synthesis of a novel nanocomposite adsorbent, comprising a crosslinked tetramethacrylate macromonomer, tetra(2-hydroxy-3-(methacryloyloxy)benzene-1,2,4,5-tetracarboxylate (TM), intercalated into cetyltrimethylammonium bromide (CTAB) modified montmorillonite (CTA-MMT). The goal was to design an efficient adsorbent for dye removal from water. The synthesis process involved intercalating the TM macromonomer into the interlayer spaces of organophilic CTA-MMT, followed by in-situ crosslinking at 50 °C. This resulted in a stable nanocomposite structure with enhanced dye adsorption capabilities. XRD, SEM, and FTIR analysis confirmed successful intercalation and the formation of an amorphous material. The TM-CTA-MMT nanocomposite effectively adsorbed methylene blue (MB) dye, with removal efficiencies of 41.3 %, 82.8 %, and 97.8 % using 40 mg, 80 mg, and 120 mg of adsorbent, respectively, in 24 h at 25 °C. At 318 K (45 °C), the MB removal efficiency reached 94.2 % in 3 h with 120 mg of adsorbent. The adsorption process demonstrated a strong fit with the pseudo-first-order kinetic model and the Langmuir isotherm model, achieving a maximum adsorption capacity of 4.74 mg/g. In contrast, the Freundlich and Temkin models exhibited significantly poorer fits to the data, indicating less applicability to the adsorption mechanism observed. Thermodynamic parameters indicated physisorption with a positive ΔH° value of 24.1 kJ/mol, while negative ΔG° values demonstrated spontaneous and favorable MB dye adsorption, highlighting the nanocomposite's potential for efficient cationic dye removal from aqueous solutions.Abstract
This study introduces the synthesis of a novel nanocomposite adsorbent, comprising a crosslinked tetramethacrylate macromonomer, tetra(2-hydroxy-3-(methacryloyloxy)benzene-1,2,4,5-tetracarboxylate (TM), intercalated into cetyltrimethylammonium bromide (CTAB) modified montmorillonite (CTA-MMT). The goal was to design an efficient adsorbent for dye removal from water. The synthesis process involved intercalating the TM macromonomer into the interlayer spaces of organophilic CTA-MMT, followed by in-situ crosslinking at 50 °C. This resulted in a stable nanocomposite structure with enhanced dye adsorption capabilities. XRD, SEM, and FTIR analysis confirmed successful intercalation and the formation of an amorphous material. The TM-CTA-MMT nanocomposite effectively adsorbed methylene blue (MB) dye, with removal efficiencies of 41.3 %, 82.8 %, and 97.8 % using 40 mg, 80 mg, and 120 mg of adsorbent, respectively, in 24 h at 25 °C. At 318 K (45 °C), the MB removal efficiency reached 94.2 % in 3 h with 120 mg of adsorbent. The adsorption process demonstrated a strong fit with the pseudo-first-order kinetic model and the Langmuir isotherm model, achieving a maximum adsorption capacity of 4.74 mg/g. In contrast, the Freundlich and Temkin models exhibited significantly poorer fits to the data, indicating less applicability to the adsorption mechanism observed. Thermodynamic parameters indicated physisorption with a positive ΔH° value of 24.1 kJ/mol, while negative ΔG° values demonstrated spontaneous and favorable MB dye adsorption, highlighting the nanocomposite's potential for efficient cationic dye removal from aqueous solutions
Factors influencing teachers' self-efficacy on inclusive music education
No full textAbstract
This study investigated how teachers’ attitudes towards inclusive education and support from school management and community are related to their self-efficacy in the context of inclusive music education. Participants (n = 185) were teachers from Finnish comprehensive schools (Grades 1–9). They answered three questionnaires: the Teacher Efficacy for Inclusive Practice scale, the Attitudes towards Inclusion scale, and the School Climate for Inclusive Music Education scale. Using linear regression analysis, we found that the more positive the feelings towards inclusive music classes were, the stronger the teacher’s self-efficacy was in inclusive instructions, collaboration, and managing behaviour. Moreover, the more substantial the experienced support from the school community was, the stronger the teachers’ self-efficacy was in collaboration. However, beliefs on inclusive education and perceived support from school management did not show significant effects on teacher self-efficacy in inclusive music education. These findings highlight the importance of music teachers gaining positive experience in inclusive education. This implies the crucial need for sufficient training for inclusive settings and ensuring that the environment and starting points are adequate for teaching and learning music in the classroom. Results also show the impact of the school community on success when implementing inclusive music education.Abstract
This study investigated how teachers’ attitudes towards inclusive education and support from school management and community are related to their self-efficacy in the context of inclusive music education. Participants (n = 185) were teachers from Finnish comprehensive schools (Grades 1–9). They answered three questionnaires: the Teacher Efficacy for Inclusive Practice scale, the Attitudes towards Inclusion scale, and the School Climate for Inclusive Music Education scale. Using linear regression analysis, we found that the more positive the feelings towards inclusive music classes were, the stronger the teacher’s self-efficacy was in inclusive instructions, collaboration, and managing behaviour. Moreover, the more substantial the experienced support from the school community was, the stronger the teachers’ self-efficacy was in collaboration. However, beliefs on inclusive education and perceived support from school management did not show significant effects on teacher self-efficacy in inclusive music education. These findings highlight the importance of music teachers gaining positive experience in inclusive education. This implies the crucial need for sufficient training for inclusive settings and ensuring that the environment and starting points are adequate for teaching and learning music in the classroom. Results also show the impact of the school community on success when implementing inclusive music education
Unravelling the role of iron oxidation states in alkali-activated slags: A multinuclear solid-state NMR study on polymerization and structural evolution
No full textAbstract
Understanding the structure and polymerization behavior of Fe-bearing alkali-activated slags (AASs) is crucial for optimizing their macroscopic properties and expanding their applications in sustainable construction materials, radioactive waste storage, carbon sequestration, and other environmental technologies. This paper investigates the effect of iron oxidation state in precursor slags on the polymerization and microstructural evolution of synthesized AASs using advanced solid-state NMR with 1D MAS and 2D 3QMAS experiments. 57Fe Mössbauer spectroscopy and Raman spectroscopy further provide insights into Fe coordination and phase composition. The synthesized slags were designed with controlled Fe content (<10 wt%), ensuring sufficient NMR spectral resolution. The results show that after 7 days of curing, AASs synthesized from Fe2+-rich slag exhibits lower structure polymerization compared to those derived from the Fe3+-rich slags. After 1 year of storage, Fe2+-rich AAS undergoes further polymerization, leading to the formation of highly connected silicate structures. Based on the NMR analysis, we propose that Fe3+ is incorporated into the AlVI site in hydrotalcite or as a charge balancing cation near the AlIV site in the bridging positions, with only a minor fraction potentially in tetrahedral coordination. This study highlights the critical role of iron oxidation state in tuning the polymerization and structural evolution of AASs, providing a fundamental understanding that can guide the design of next-generation Fe-bearing alkali-activated materials.Abstract
Understanding the structure and polymerization behavior of Fe-bearing alkali-activated slags (AASs) is crucial for optimizing their macroscopic properties and expanding their applications in sustainable construction materials, radioactive waste storage, carbon sequestration, and other environmental technologies. This paper investigates the effect of iron oxidation state in precursor slags on the polymerization and microstructural evolution of synthesized AASs using advanced solid-state NMR with 1D MAS and 2D 3QMAS experiments. 57Fe Mössbauer spectroscopy and Raman spectroscopy further provide insights into Fe coordination and phase composition. The synthesized slags were designed with controlled Fe content (<10 wt%), ensuring sufficient NMR spectral resolution. The results show that after 7 days of curing, AASs synthesized from Fe2+-rich slag exhibits lower structure polymerization compared to those derived from the Fe3+-rich slags. After 1 year of storage, Fe2+-rich AAS undergoes further polymerization, leading to the formation of highly connected silicate structures. Based on the NMR analysis, we propose that Fe3+ is incorporated into the AlVI site in hydrotalcite or as a charge balancing cation near the AlIV site in the bridging positions, with only a minor fraction potentially in tetrahedral coordination. This study highlights the critical role of iron oxidation state in tuning the polymerization and structural evolution of AASs, providing a fundamental understanding that can guide the design of next-generation Fe-bearing alkali-activated materials
Extended multi-stream temporal-attention module for skeleton-based human action recognition (HAR)
No full textAbstract
Graph convolutional networks (GCNs) are an effective skeleton-based human action recognition (HAR) technique. GCNs enable the specification of CNNs to a non-Euclidean frame that is more flexible. The previous GCN-based models still have a lot of issues: (I) The graph structure is the same for all model layers and input data. GCN model's hierarchical structure and human action recognition input diversity make this a problematic approach; (II) Bone length and orientation are understudied due to their significance and variance in HAR. For this purpose, we introduce an Extended Multi-stream Temporal-attention Adaptive GCN (EMS-TAGCN). By training the network topology of the proposed model either consistently or independently according to the input data, this data-based technique makes graphs more flexible and faster to adapt to a new dataset. A spatial, temporal, and channel attention module helps the adaptive graph convolutional layer focus on joints, frames, and features. Hence, a multi-stream framework representing bones, joints, and their motion enhances recognition accuracy. Our proposed model outperforms the NTU RGBD for CS and CV by 0.6% and 1.4%, respectively, while Kinetics-skeleton Top-1 and Top-5 are 1.4% improved, UCF-101 has improved 2.34% accuracy and HMDB-51 dataset has significantly improved 1.8% accuracy. According to the results, our model has performed better than the other models. Our model consistently outperformed other models, and the results were statistically significant that demonstrating the superiority of our model for the task of HAR and its ability to provide the most reliable and accurate results.Abstract
Graph convolutional networks (GCNs) are an effective skeleton-based human action recognition (HAR) technique. GCNs enable the specification of CNNs to a non-Euclidean frame that is more flexible. The previous GCN-based models still have a lot of issues: (I) The graph structure is the same for all model layers and input data. GCN model's hierarchical structure and human action recognition input diversity make this a problematic approach; (II) Bone length and orientation are understudied due to their significance and variance in HAR. For this purpose, we introduce an Extended Multi-stream Temporal-attention Adaptive GCN (EMS-TAGCN). By training the network topology of the proposed model either consistently or independently according to the input data, this data-based technique makes graphs more flexible and faster to adapt to a new dataset. A spatial, temporal, and channel attention module helps the adaptive graph convolutional layer focus on joints, frames, and features. Hence, a multi-stream framework representing bones, joints, and their motion enhances recognition accuracy. Our proposed model outperforms the NTU RGBD for CS and CV by 0.6% and 1.4%, respectively, while Kinetics-skeleton Top-1 and Top-5 are 1.4% improved, UCF-101 has improved 2.34% accuracy and HMDB-51 dataset has significantly improved 1.8% accuracy. According to the results, our model has performed better than the other models. Our model consistently outperformed other models, and the results were statistically significant that demonstrating the superiority of our model for the task of HAR and its ability to provide the most reliable and accurate results
High-performance acetone detection via one-dimensional sulfur-doped ZnO nanostructures
No full textAbstract
This study successfully synthesizes one-dimensional sulfur-doped ZnO nanostructures via vapor-phase growth. Sulfur incorporation was confirmed through shifts in X-ray diffraction patterns and photoluminescence spectra. X-ray photoelectron spectroscopy (XPS) analysis revealed increased oxygen vacancies—a critical factor for enhancing sensor reactivity. The sulfur-doped ZnO nanostructures significantly improved gas sensing performance, achieving a response of approximately 85 % due to the increase in surface oxygen vacancies and active adsorption sites. Although sulfur doping slightly reduced inter-grain conductivity, the sensors exhibited remarkable selectivity for acetone over other gases. These findings underscore the potential of sulfur-doped ZnO nanostructures for acetone detection, addressing a critical gap in current sensor research and paving the way for developing high-performance gas sensors for practical applications.Abstract
This study successfully synthesizes one-dimensional sulfur-doped ZnO nanostructures via vapor-phase growth. Sulfur incorporation was confirmed through shifts in X-ray diffraction patterns and photoluminescence spectra. X-ray photoelectron spectroscopy (XPS) analysis revealed increased oxygen vacancies—a critical factor for enhancing sensor reactivity. The sulfur-doped ZnO nanostructures significantly improved gas sensing performance, achieving a response of approximately 85 % due to the increase in surface oxygen vacancies and active adsorption sites. Although sulfur doping slightly reduced inter-grain conductivity, the sensors exhibited remarkable selectivity for acetone over other gases. These findings underscore the potential of sulfur-doped ZnO nanostructures for acetone detection, addressing a critical gap in current sensor research and paving the way for developing high-performance gas sensors for practical applications
Innovative strategy of sustainable NH4Cl leaching of high‑chlorine secondary zinc oxide and closed-loop chlorine recovery via natural cooling crystallization
No full textAbstract
High‑chlorine secondary zinc oxide (HCSZO), enriched in Zn, Pb, Cu, Cd, and Cl, holds considerable potential for resource recovery. However, conventional sulfuric acid treatment suffers from severe drawbacks, including electrode corrosion, accelerated degradation of metallurgical equipment, and deterioration of the working environment. Developing an economical and environmentally friendly method for HCSZO disposal remains a significant challenge. This study systematically investigates the leaching behavior of HCSZO in NH4Cl solution and proposes the recovery of NH4Cl from ammonia-based electrolytes via natural cooling crystallization. Under optimal conditions, high leaching efficiencies of Zn (91.00 %), Cu (89.97 %), and Pb (81.83 %) were achieved. The resulting leach residue contained 4.73 % Pb and 13.57 % Fe, with only 1.22 % Cl, making it suitable for rotary kiln recycling. Mechanistic analysis revealed that ZnO in HCSZO progressively transforms into Zn(NH3)i2+ (i = 1, 2, 3, 4) through intermediate ZnCli2-i complexes, facilitated by the synergistic action of Cl− and NH4+ with increasing temperature and pH. DFT simulations showed ZnO preferentially interacts with H+, enabling four leaching pathways and confirming an external diffusion-controlled mechanism with low activation energy. Cu(I) is oxidized by H2O2 and complexes with NH4+ to form Cu(NH3)i2+, as confirmed by mixed-phase analysis, while Pb3O4 undergoes leaching to yield PbO2 and PbCli(2-i) complexes. To address the issue of Cl− accumulation during cyclic leaching, NH4Cl crystals containing only 0.52 % Zn were recovered from the electrolyte via natural cooling crystallization, enabling open-circuit chlorine management. This work not only achieved efficient extraction of valuable metals from HCSZO, but also effectively mitigated chlorine enrichment in both residues and electrolytes, which is typically difficult to manage. The findings offer theoretical and technical guidance for optimizing HCSZO leaching and improving Cl resource utilization within the Zn–NH4Cl–H2O system.Abstract
High‑chlorine secondary zinc oxide (HCSZO), enriched in Zn, Pb, Cu, Cd, and Cl, holds considerable potential for resource recovery. However, conventional sulfuric acid treatment suffers from severe drawbacks, including electrode corrosion, accelerated degradation of metallurgical equipment, and deterioration of the working environment. Developing an economical and environmentally friendly method for HCSZO disposal remains a significant challenge. This study systematically investigates the leaching behavior of HCSZO in NH4Cl solution and proposes the recovery of NH4Cl from ammonia-based electrolytes via natural cooling crystallization. Under optimal conditions, high leaching efficiencies of Zn (91.00 %), Cu (89.97 %), and Pb (81.83 %) were achieved. The resulting leach residue contained 4.73 % Pb and 13.57 % Fe, with only 1.22 % Cl, making it suitable for rotary kiln recycling. Mechanistic analysis revealed that ZnO in HCSZO progressively transforms into Zn(NH3)i2+ (i = 1, 2, 3, 4) through intermediate ZnCli2-i complexes, facilitated by the synergistic action of Cl− and NH4+ with increasing temperature and pH. DFT simulations showed ZnO preferentially interacts with H+, enabling four leaching pathways and confirming an external diffusion-controlled mechanism with low activation energy. Cu(I) is oxidized by H2O2 and complexes with NH4+ to form Cu(NH3)i2+, as confirmed by mixed-phase analysis, while Pb3O4 undergoes leaching to yield PbO2 and PbCli(2-i) complexes. To address the issue of Cl− accumulation during cyclic leaching, NH4Cl crystals containing only 0.52 % Zn were recovered from the electrolyte via natural cooling crystallization, enabling open-circuit chlorine management. This work not only achieved efficient extraction of valuable metals from HCSZO, but also effectively mitigated chlorine enrichment in both residues and electrolytes, which is typically difficult to manage. The findings offer theoretical and technical guidance for optimizing HCSZO leaching and improving Cl resource utilization within the Zn–NH4Cl–H2O system
Podcastien käyttö lääketieteen perusopetuksessa
No full textPodcastit tarjoavat joustavan ja innovatiivisen lisän lääketieteen opetukseen sekä tukevat opiskelijoiden itsenäistä opiskelua ja elinikäistä oppimista. Niitä voidaan käyttää muun muassa ennakko- ja tukimateriaalina, täydentävänä oppimateriaalina tai opiskelijoiden itse tuottamina sisältöinä. Podcastien etuja ovat joustavuus, yksilöllisen oppimisen tukeminen ja mahdollisuus oppia muiden toimintojen ohessa. Haasteita ovat muun muassa visuaalisuuden ja vuorovaikutuksen puuttuminen. Laadukasta tutkimusnäyttöä podcastien vaikutuksesta oppimistuloksiin ei toistaiseksi ole. Podcastit voivat kuitenkin rikastuttaa oppimiskokemusta, edistää ammatti-identiteetin rakentamista ja tarjota käytännön keinoja esimerkiksi moniammatillisen yhteistyön opettamiseen.Podcastit tarjoavat joustavan ja innovatiivisen lisän lääketieteen opetukseen sekä tukevat opiskelijoiden itsenäistä opiskelua ja elinikäistä oppimista. Niitä voidaan käyttää muun muassa ennakko- ja tukimateriaalina, täydentävänä oppimateriaalina tai opiskelijoiden itse tuottamina sisältöinä. Podcastien etuja ovat joustavuus, yksilöllisen oppimisen tukeminen ja mahdollisuus oppia muiden toimintojen ohessa. Haasteita ovat muun muassa visuaalisuuden ja vuorovaikutuksen puuttuminen. Laadukasta tutkimusnäyttöä podcastien vaikutuksesta oppimistuloksiin ei toistaiseksi ole. Podcastit voivat kuitenkin rikastuttaa oppimiskokemusta, edistää ammatti-identiteetin rakentamista ja tarjota käytännön keinoja esimerkiksi moniammatillisen yhteistyön opettamiseen
Resistive Switching Behaviors in Vertically Aligned MoS2 Films with Cu, Ag, and Au Electrodes
No full textAbstract
Neuromorphic computing circuits can be realized by using memristors based on low-dimensional materials enabling enhanced metal diffusion for resistive switching. Here, we investigate memristive properties of vertically aligned MoS2 (VA-MoS2) films with three different metal electrodes: Ag, Cu, and Au. Despite having the same active material, all three metals show distinct switching behavior, which is crucial for neuromorphic computing applications: Ag enables volatile switching, Cu demonstrates stable nonvolatile switching with retention over 2500 s, and Au shows no memristive response. Cu devices show abrupt resistance changes and a significant increase of copper content upon biasing, indicative of stable nonvolatile switching based on filament formation and rupture. About 85% of Ag and Cu devices exhibit reliable memristor behavior. Our findings provide valuable insights into the memristive switching mechanism in VA-MoS2 and present a promising avenue for facile fabrication of neuromorphic circuits by employing a set of different metals on a single active material.Abstract
Neuromorphic computing circuits can be realized by using memristors based on low-dimensional materials enabling enhanced metal diffusion for resistive switching. Here, we investigate memristive properties of vertically aligned MoS2 (VA-MoS2) films with three different metal electrodes: Ag, Cu, and Au. Despite having the same active material, all three metals show distinct switching behavior, which is crucial for neuromorphic computing applications: Ag enables volatile switching, Cu demonstrates stable nonvolatile switching with retention over 2500 s, and Au shows no memristive response. Cu devices show abrupt resistance changes and a significant increase of copper content upon biasing, indicative of stable nonvolatile switching based on filament formation and rupture. About 85% of Ag and Cu devices exhibit reliable memristor behavior. Our findings provide valuable insights into the memristive switching mechanism in VA-MoS2 and present a promising avenue for facile fabrication of neuromorphic circuits by employing a set of different metals on a single active material