VTT Research System
Not a member yet
161399 research outputs found
Sort by
CeOx-functionalized Pd nanoparticles on single-walled carbon nanotubes for alkaline hydrogen oxidation reaction
No full textThe sluggish kinetics of hydrogen oxidation reaction (HOR) in alkaline electrolytes highlight the strong need to develop next-generation catalyst materials for anion-exchange membrane fuel cells (AEMFC) anodes. In this study, CeOx is sequentially deposited on Pd nanoparticles supported on single-walled carbon nanotubes (SWNT) via atomic layer deposition (ALD). The obtained Pd@CeOx SWNT16 ALD cycles catalyst shows an excellent alkaline HOR performance with a specific exchange current of 166 mA mg−1Pd. This is three times higher than the commercially available Pd catalyst and the highest among reported Pd/CeOx catalyst materials with different CeOx overlayer coverages. By combining the X-ray diffraction, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and high-resolution scanning transmission electron microscopy, we confirm that the activity improvement is due to the highly conductive SWNT support enabling the fabrication of high surface area Pd clusters and CeOx overlayer. These methods reveal that the oxidation state of Ce is varying from Ce3+ to Ce4+ in relation to the CeOx overlayer thickness and the number of ALD cycles. Density functional theory calculations show that the presence of Ce/CeOx increases the diversity and population of Pd active sites with improved activity in its vicinity leading to enhanced overall catalytic performance. Moreover, this work provides a new perspective to develop highly active alkaline HOR catalysts for AEMFC
A state-of-the-art review of R&D for the supercritical water-cooled reactor technology. Part II materials & chemistry
No full textThis document presents a summary of the most relevant research and development (R&D) carried out to support the development of the only generation IV water-cooled reactor endorsed by the Generation IV International Forum (GIF).The coolant of the proposed reactor operates at supercritical water conditions, allowing for an increase in thermodynamic efficiency of the plant and the production of high-grade process heat. Several collaborations have been established to support this technology under the GIF umbrella as well as through other international avenues; as a result, the development work is bolstered by a collective effort between numerous R&D institutions across Asia, Europe, and North America. The Joint European Canadian Chinese development of Small Modular Reactor Technology (ECC-SMART) collaborative project was established to encompass the design and pre-licensing requirements as well as a roadmap demonstrating the safe operation of the supercritical water small modular reactor (SCW-SMR). One of the main challenges in the material and component aspect is the selection and qualification of a fuel cladding material that can withstand supercritical water conditions (beyond 374 °C and 22.1 MPa). The aim of the materials testing work package (WP2) in the ECC-SMART project is to achieve a deep understanding of the corrosion behavior of selected candidate cladding materials. Over 750 corrosion specimens were tested including those under nominal SCW-SMR operating conditions and also at simulated accident conditions. This article summarizes the findings from the study of corrosion behavior of non-irradiated and pre-irradiated candidate materials and from the study of the effect of chemistry and changes in the chemical properties of SCW.</p
Analysis of elastic and plastic behaviour in untreated pine wood under scratch test loads combining X-ray computed tomography and finite element simulations
No full textWood is an anisotropic material, which affects its performance under different loading conditions. To understand the origin of surface failures occurring in wood under mechanical disintegration loads, an accurate investigation of its elastic and plastic behaviour is required. This study introduces a methodology that integrates experimental scratch testing, X-ray micro-computed tomography (μCT), and finite element simulations to examine the elastic and plastic deformation and failure behaviour of untreated pine wood under scratch loading. In the existing literature, scratch testing is primarily employed to assess coating adhesion or material abrasion resistance; its use for probing the mechanical response of wood remains limited. In the present study, scratches were applied to pine specimens in the radial, tangential, and longitudinal directions of wood using a diamond indenter under constant normal loads perpendicular to the scratched surface. The permanent residual depths measured by μCT were compared with FE-predicted deformations. The selected methodology enables quantification of the relationship between wood structure, loading conditions, and scratch performance. The results demonstrated that the regions with higher density favoured elastic deformation, whereas the residual scratch depth, reflecting plastic deformation, provided a reliable indicator of scratch resistance, exhibiting higher scratch resistance for the higher density wood. In particular, the wood with higher density showed residual depths in the range of 53–144 µm in radial direction scratches, whereas the less dense wood showed values between 90 and 300 µm. μCT imaging also revealed detailed deformation mechanisms and fracture pathways that develop under scratch-type loading. By coupling μCT with FE modelling for wood scratch mechanics, the work deepens the understanding of how wood microstructure responds to different scratch loading conditions. The findings can serve as a scientific reference for future experimental and numerical investigations of scratching, cutting and other disintegration loads in untreated wood and wood-based composites at the microscale.</p
A Review of Public Funding for Agri-Food Exports, 2020–2025
No full textThis report examines the public funding supporting Finnish food exports and internationalization from 2020 to 2025. The study maps key funding sources – including Business Finland, European structural funds, the Rural Development Fund, the European Maritime, Fisheries and Aquaculture Fund (EMFAF), and EU promotion programs – and analyzes their support in fostering food sector growth. The analysis highlights the multi-stage export pathway for food companies, from local business development to international market entry and scaling, emphasizing the complementary roles of innovation funding, regional development, and sectoral collaboration. The report focuses on two themes: export promotion and internationalization, and food tourism. Results show that 48.2 million euros in public support were granted, with the majority directed at companies and also to research and education organisations. Municipalities, city actors and non-profit organizations had a smaller share of the funding. The study also addresses the challenges of data comparability and the need for unified terminology and impact metrics. Recommendations include improving data systems, harmonizing concepts, and developing better impact assessment tools to support the ambitious national goal of doubling food exports by 2031
Superbases as Organocatalysts in Low Temperature Glycolytic Depolymerization of Polyethylene Terephthalate (PET)
No full textChemical recycling offers a prospective solution for valorizing the vast amount of diverse polyethylene terephthalate (PET) waste generated from various streams. Rigid and flexible packaging such as bottles, and films, or textiles, optionally containing also comonomers like polypropylene terephthalate (PPT) and polybutylene terephthalate (PBT), are essential materials to be considered. In this study, low temperature depolymerization of PET was investigated by implementing glycolysis as the chemical recycling method. In glycolysis of PET, the polymer is depolymerized in excess ethylene glycol and presence of catalyst into bis(2-hydroxyethyl) terephthalate (BHET) monomer. The monomer can be re-utilized as feedstock for the manufacturing of recycled virgin-like PET. Herein we report utilization of novel mTBN guanidine superbase (mixture of two isomers, 7-methyl-1,5,7-triazabicyclo-[4.3.0]non-5-ene & 5-methyl-1,5,7-triazabicyclo-[4.3.0]non-6-ene) as efficient organocatalyst for glycolysis of virgin and post-consumer PET materials. Three guanidine compounds were screened as catalyst under various conditions and their efficiency was compared to zinc acetate, which is a conventionally applied transesterification catalyst. All superbases achieved high PET conversions of over 90 % at low reaction temperature of 140 °C within 2 h, while Zn(OAc) 2 showed only 18 % conversion. Moreover, mTBN superbase was the most efficient by depolymerizing PET powder in just 20 min. Industrially viable conversions of over 90 % resulted in BHET monomer recovery of over 40 % determined by mass. Size-exclusion chromatography (SEC) results indicate that reaction temperature has significant influence on the depolymerization reaction depth. Furthermore, experiments with different PET feedstocks demonstrate the significance of materials’ surface area towards depolymerization efficiency.</p
Enzyme-Directed Assembly of Antiparallel Cellulose II Nanocrystals:Unraveling the Mechanism Beyond Spontaneous Crystallization
No full textHumans have long utilized cellulose II, known as regenerated cellulose, for fibers like rayon and Cupra and films like cellophane. While cellulose I, found in nature, consists of parallel molecular chains, cellulose II is characterized by the stable arrangement of molecules in an antiparallel orientation. Enzymatic synthesis of cellulose in vitro also affords cellulose II with various morphologies, from monolayer lamellae crystals to gels, but its formation mechanism remains obscure. Here, we demonstrate that cellodextrin phosphorylase (CDP) catalyzes the synthesis and orchestrates the antiparallel self-assembly of cellulose II nanocrystals, exceeding the paradigm of spontaneous crystallization. High-resolution structural analysis reveals CDP’s key role in dictating crystal size and alignment, bridging the gap between enzymatic catalysis and biodirected material architecture. Our research unveils a unique protein-templated assembly process for advanced cellulose materials, paving the way for enzyme-guided construction of next-generation functional nanostructures.</p
Scientific assessment for urban air mobility (UAM)
No full textThis review article is the revised and expanded version of the Scientific Assessment for UAM document that the urban air mobility (UAM) working group of the International Forum for Aviation Research (IFAR) developed at the request of the International Civil Aviation Organization (ICAO). The assessment began with a study of the industry landscape, which includes an overview of existing market studies, proposed aircraft designs and concepts, and potential paths for industry evolution. The subsequent scientific assessment, developed through cooperative efforts among international domain experts, captures 17 focus areas relevant to UAM. Each focus area presents opportunities for further research. The assessment was delivered to the ICAO in 2023. This revised and expanded version reflects the UAM domain’s status quo, incorporating the most recent developments and trends identified in 2024. Key takeaways include: the need for further study of the impact of autonomous systems on the industry; infrastructure requirements (including vertiports and weather sensing) to support the industry sector; and data requirements (covering domains such as cybersecurity, emissions, and safety) to ensure safe and scalable UAM operations.</p
Solvent-Mediated Dewetting Principles for Cell-Sized Liposome Formation
No full textReconstitution of synthetic cells holds potential to advance synthetic biology, biomanufacturing, and therapeutics. Microfluidic generation of cell-sized liposomes via double emulsion templating offers precise control over composition and formation process, yet the principles underlying solvent-mediated dewetting remain poorly understood. Using a solvent combination of hexanol and paraffin oil, we demonstrate that solvent-mediated dewetting liposome generation entails both solvent removal and the application of mechanical stimuli. Solvent removal suffices to induce the morphological transition from double emulsions to partially dewetted liposomes exhibiting low and high budding angles of the residual oil pockets. This transition is driven by relaxation of monolayer and membrane tensions, arising from the increased lipid packing density at the liposome interfaces during solvent depletion. While dewetting kinetics and intermediate stages are governed by solvent removal rate, complete dewetting is not spontaneous. Using optical tweezers, we identify tethering between the liposome and oil pocket and characterize the mechanical force required for liposome detachment. By integrating these principles, a predictive, high-throughput approach for generating biocompatible, surfactant-free liposomes is provided. These findings establish a mechanistic framework for liposome dewetting and, through similarities to lipid droplet morphogenesis, offer a protocell platform that could further the understanding of biological budding processes.</p
Surface characteristics and repulpability performance of cellulose-fiber-based packaging materials coated with aqueous dispersions of wood-bark-derived suberin
No full textRecyclability is an important feature of packaging materials. Although packaging materials made from cellulose fibers such as those found in paper or paperboard can typically be recycled through repulping, the application of coatings, especially polymeric plastic coatings, often impairs their recyclability, leading to increased amounts of rejects and low fiber yields. Herein, the surface properties and repulpability performance of paperboard substrates coated with aqueous dispersion of wood bark-derived suberin, stabilized using synthetic surfactants or bio-based surfactants, were investigated. The results were compared with commercial polyethylene coated material. Surface properties of the materials were investigated through surface imaging, water absorption, and wettability measurements. Repulpability was evaluated based on the amounts of rejects after two screening stages. Fiber analysis was performed for the materials that passed both the screenings. All suberin-coated materials showed hydrophilic surface characteristics and greater water absorbency than the reference material. Repulpability analysis revealed that the suberin coatings resulted in a lower amount of rejects than coated reference material. These results highlight the potential of suberin coatings in developing recyclable and sustainable packaging solutions for cellulose fiber substrates
Business Model (BM) Transformations in Business-to-Business (B2B) Digital Multimodal Logistics Platform Ecosystem:Insights from Prospective Marketplace Sellers and Buyers
No full textDigitalization and sustainability imperatives are transforming the logistics industry; however, the evolution of business models (BMs) in emerging business-to-business (B2B) digital multimodal marketplaces has not been thoroughly explored. This study investigates how one of the first B2B digital multimodal marketplace ecosystems – designed to calculate emissions and promote more sustainable logistics services – might affect the BMs of sellers and buyers. We used a qualitative research design based on the Business Model Canvas (BMC). To gather data, we analyzed the current (AS-IS) and future (TO-BE) BMs. Additionally, we created detailed questionnaires structured around the BMC framework, which were completed by representatives from seller and buyer actor groups. A hybrid deductive-inductive coding approach allowed us to integrate the established BMC framework with emergent themes. Our analysis reveals significant potential transformations in the key activities, followed by potential changes in key resources, channels and revenue streams. Most BM changes centre on adding emission calculation as a new value-proposition element, which in turn triggers adjustments in the other BMC blocks. These insights deepen the theoretical understanding of how digital logistics marketplace ecosystem might drive BM transformation, while also highlighting the anticipated challenges, risks, and necessary adjustments managers in the logistics industry should address when integrating a digital marketplace ecosystem. This study is one of the first to analyze likely changes in the BMs of companies adopting a B2B digital logistics platform ecosystem. Additionally, it is the first to explore a multimodal and environmentally conscious platform ecosystem