VTT Research System
Not a member yet
161399 research outputs found
Sort by
Electrification of district heating: The impact of electricity price volatility and distribution temperatures on the optimal capacity mix
No full textBecause of the increasing share of variable renewable energy in the power sector, the volatility of the electricity price has increased greatly. This, the electricity tax relief, and concerns about sustainability of combustible fuels have boosted the power-to-heat investments in the Finnish district heating systems. Especially, electric boilers, which have been nearly non-existent in the Finnish district heating systems, will see a rapid roll-out in the next few years. In this study, Backbone modelling framework was used to investigate the impact of increasing volatility of electricity price on optimal power-to-heat and thermal energy storage investments in the Finnish capital region. The impact of decreasing district heating temperatures was analysed as well. The sensitivity of the results to energy prices and thermal energy storage costs was tested.The results show that more volatile electricity price increased the profitability of the electric boilers and heat storages. Larger electric boiler capacity led to higher electricity consumption and peak power demand. The profitability of the heat pumps increased significantly with lower district heating temperatures, which also decreased the electricity consumption of the district heating system. The optimal capacity mix of the P2H technologies and heat storages was highly sensitive to the cost assumptions of the fuels and heat storages, but the total costs increased only a little, if the model was run with suboptimal capacity mix. Lower fuel prices decreased the heat pump investments, and higher prices increased. The impact of fuel prices on the electric boiler investments was not as clear
Microfluidic electro-viscoelastic manipulation of extracellular vesicles
No full textMicrofluidic technology has created new opportunities for developing innovative tools for biological applications. Given the significance of extracellular vesicles (EVs), extensive research has focused on developing microfluidic techniques for EV isolation. This research protocol presents electro-viscoelastic microfluidics as a novel approach for manipulating EVs. The system leverages the viscoelasticity of the suspending medium along with an externally applied electric field to alter EV motion within a microchannel. These findings suggest that our electro-viscoelastic microfluidic system has the potential for further development to be used for EV isolation.</p
Biobased barrier dispersion coating from solvent shifting of functionalized lignin inside cellulose nanofibers aqueous suspensions
No full textIn this study, we present a simple one-pot approach to formulate barrier dispersions by combining nanoscaled cellulose and lignin, while harnessing the hydrophobizing effect of tall oil fatty acid (TOFA) modification. Using an in situ solvent-shifting method, unmodified lignin and TOFA-esterified lignin solutions were directly incorporated into aqueous microfibrillated cellulose (MFC) suspensions, enabling the in situ formation of stable lignin nanoparticles (LNPs and TOFA-LNPs) within the MFC matrix. Nanopapers prepared from TOFA-LNP:MFC dispersion with a ratio of 1:2 exhibited excellent barrier properties, with a water vapor transmission rate of 6 g/m²·day (50 % RH, 23 °C), an oil Cobb1800 value of 0.3 g/m², and a water Cobb1800 value of 12 g/m². The results demonstrate that TOFA modification of lignin and its incorporation within the MFC matrix as nanoparticles, facilitates the formation of dense, uniform films with strong resistance to moisture and oil. To gain a deeper understanding of the system, surface-sensitive quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM) were used to analyze how the TOFA modification of lignin affected its physicochemical interactions within cellulose fibrils. Furthermore, humidity-controlled QCM-D measurements were used to analyze the effect of lignin-based nanoparticles on the water vapor adsorption behavior of MFC at different relative humidities providing new insights into their barrier performance, explored here for the first time. Finally, the successful application of dispersion coatings onto commercial fiber-based substrates demonstrates their industrial potential. This work introduces a versatile and scalable route to fully biobased coatings, advancing the transition toward circular and sustainable packaging solutions.</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
High-Resolution Synchrotron µXRD and µXRF for Local Phase and Elemental Analysis in Suspension Plasma Sprayed Environmental Barrier Coatings
No full textSuspension plasma spraying (SPS) enables the fabrication of environmental barrier coatings (EBCs) with complex multilayer architectures; however, degradation in such systems often initiates locally at buried interfaces, making it difficult to resolve using conventional laboratory-scale characterization techniques. In this work, the applicability of synchrotron-based micro-x-ray diffraction (µXRD), combined with micro-x-ray fluorescence (µXRF), is evaluated for the characterization of SPS-deposited ytterbium disilicate (YbDS) EBCs. An as-sprayed YbDS coating was investigated as a baseline case to examine differences between conventional XRD and spatially resolved µXRD, while an annealed and CMAS-exposed YbDS coating was studied as a service-relevant case to probe localized phase evolution. The samples were selected from previously optimized SPS process conditions and are not intended for direct comparison. Laboratory-scale XRD provided global phase information, whereas µXRD enabled layer-specific phase identification and resolved localized interfacial features. In the as-sprayed condition, µXRD confirmed phase-pure YbDS, resolved the crystallinity of individual coating layers, and verified the absence of unintended interfacial reaction phases that are not accessible by conventional XRD. In the annealed + CMAS-exposed coating, µXRD and µXRF revealed the formation of a calcium–ytterbium–silicate oxyapatite phase confined to the YbDS/Si interface, highlighting the localized nature of CMAS-induced degradation. These results demonstrate that synchrotron microanalysis provides valuable complementary insight for probing localized phase evolution in thermally sprayed EBC systems.</p
Techno-functional and nutritional evaluation of Solein single-cell protein and its application in non-dairy yoghurt alternatives
No full textThe growing global population and climate crisis demand expanding non-animal protein options. Single-cell protein biomass, referred to as “Solein”, is produced by the hydrogen-oxidising bacterium Xanthobacter sp. SoF1 and is a promising, sustainable source of protein and dietary fibre, especially when created using renewable energy. This study investigates Solein protein powder (SPP) for its composition and techno-functional properties, comparing it to pea protein isolate (PPI). SPP had a lower fat content and higher dietary fibre, while matching the protein content of PPI. SPP met all indispensable amino acid requirements for adults over the age of three, as outlined by the FAO in 2013. A milk alternative resembling semi-skimmed cow's milk was produced from SPP and PPI. These emulsions were fermented with a commercial starter culture containing Streptococcus thermophilus. The fermentation process was monitored by tracking pH, total titratable acidity, and microbial growth. The resulting yoghurt alternative (YA) underwent textural and rheological analysis. Solein protein powder yoghurt alternative (SPP-YA) exhibited faster acidification, greater microbial growth, improved water retention, and a texture similar to dairy yoghurt. Static in vitro digestion revealed moderate protein digestibility of the non-fermented SPP emulsion (63.8–67.5%), based on total amino acids, free amino groups, and total nitrogen, with an in vitro Digestible Indispensable Amino Acid Score (DIAAS) of (51.0 ± 6.1%). Fermentation slightly reduced digestibility (57.8–59.6%) and DIAAS (48.3 ± 1.4%), with isoleucine as the limiting amino acid. This work provides the first insight into the structural and nutritional performance of hydrogen-oxidising bacterial protein in non-dairy YA.</p
Collaborative Foresight: Major Research Trajectories and Future Research Agenda
No full textCollaborative foresight is increasingly recognized as an important tool for anticipating and shaping the future through engagement with diverse stakeholders. While academic interest in the topic has grown, highlighting its significance, the field remains fragmented. Literature on collaborative foresight is characterized by varying definitions, multiple theoretical foundations, and diverse methodological approaches. This study conducts a bibliometric review to structure the field of collaborative foresight studies, identifying four central research trajectories: (1) Collaboration in Technology Foresight, (2) Collaboration in Scenario Planning, (3) Open Foresight, and (4) Collaboration in Anticipatory Governance. Based on this structured analysis, we identify key research gaps, including the absence of a widely accepted definition of collaborative foresight, weak linkages to ecosystem and strategic management theories, and a lack of structured impact assessments to measure the long-term benefits of collaborative foresight. To address these gaps, we propose a research agenda emphasizing the development of robust theoretical foundations, stronger connections to strategic decision-making, and methodological improvements to enhance the practice and impact of collaborative foresight
Optimizing an iron- and manganese-based electrocatalyst for the oxygen evolution reaction in a proton exchange membrane electrolyzer
No full textThe development of electrocatalysts based on earth-abundant elements has gained significant attention due to the scarcity and high cost of Ir- and Ru-based materials typically used in proton exchange membrane electrolyzers (PEMELs). This study focuses on Fe-Mn-based catalysts for promoting the oxygen evolution reaction (OER), the sluggish four-electron process at the anode of PEMELs, where acidic conditions and high anodic potentials (1.6–2.0 V RHE) often accelerate corrosion. The catalysts were synthesized via a hydrothermal method and optimized using a response surface design of experiments (DOE), followed by detailed physicochemical characterization. The optimized composition ( [Figure presented] ) demonstrates good electrochemical activity and stability, maintaining performance over 10,000 potential cycles between 1.2 and 2.0 V RHE, with a moderate shift in the overpotential required to reach 10 mAcm −2 (from 1.78 V iR−corr vs RHE to 1.84 V iR−corr vs RHE). Inductively coupled plasma mass spectrometry of flow cells scanning (SFC-ICP-MS) confirms high stability at elevated potentials, showing reduced [Figure presented] to [Figure presented] oxidation. At lower potentials (≤1.4V RHE), dissolution signals indicate reductive leaching of Fe and Mn. Integration of the catalyst into a laboratory PEMEL demonstrate operational stability, sustaining 10 mAcm −2 at 50 °C over 80 h, with a 50 mV increase in iR-corrected potential (1.82 to 1.87 V).</p
From Leaves to Breezes: Machine learning based prediction of nitrogen dioxide concentration from surrounding urban greenery and meteorological, spatial, and traffic characteristics in Berlin, Germany
No full textThis study compares two machine learning models, a Random Forest (RF) and a spatial Graph Neural Network (GNN), for predicting nitrogen dioxide (NO) concentrations across diverse urban conditions in Berlin, Germany. Therefore, both models use information on local land-use characteristics, meteorological conditions, and seasonal greenery, which enables a post-hoc analysis of high-concentration scenarios under varying environmental factors. Unlike most previous approaches to air-pollution estimation, this study explicitly considers the interaction between urban greenery and its seasonal variation. The analysis is based on a self-curated, high-resolution site-level environmental dataset that captures hourly NO observations from sixteen monitoring stations across Berlin in 2023 with detailed land-use, traffic, and architectural data obtained from the Berlin Geoportal. This dataset is supplemented with multiple meteorological records from the Deutscher Wetterdienst (DWD). While both models achieve comparable accuracy (R 0.6), the GNN shows a tendency toward less variation of predictive accuracy across test sites, suggesting potential spatial robustness. For explainability, only the RF model allows for local interpretability via Shapley values, which indicate that urban greenery helps mitigate NO levels depending on seasonal changes in leaf area. However, additional statistical testing does not support this observed trend. Beyond the conducted assessment, this research contributes a comprehensive environmental dataset that links air quality, land-use, and meteorological variables at hourly resolution. This resource supports future investigations into how environmental and spatial factors jointly influence pollutant dispersion and decomposition in urban environments