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On the accuracy of the measured and modelled surface latent and sensible heat flux in the interior of the Greenland Ice Sheet
No full textAbstract
The latent (LHF) and sensible (SHF) heat fluxes are key components of the surface mass and energy balance in the accumulation area of the Greenland Ice Sheet, making them critical for accurate sea level projections. While Eddy-Covariance (EC) systems provide accurate measurements of the turbulent surface transport of mass and energy in the low and mid-latitudes, frequent stable boundary layer conditions in polar regions introduce uncertainties in the EC method. In addition, as EC measurements are sparse, it is critical to characterise biases in the more common bulk fluxes obtained from automatic weather stations and climate models in polar areas. In this study, we present an intercomparison of three independent EC systems from the 28 May until 31 July 2019 at the EastGRIP site at ∼ 2700 m a.s.l. on the Greenland Ice Sheet to assess the accuracy of LHF and SHF measurements. A comparison of the fluxes by the three systems demonstrates excellent agreement with an absolute bias of 0.2 W m−2 and slopes between 1.01 and 1.16 for the LHF, and an absolute bias of less than 0.5 W m−2 and slopes of 1.0 for the SHF. A comparison of the validated EC fluxes against the bulk method highlights the sensitivity to the site-specific roughness length z0,m and the limitation of common parameterisations of the humidity and temperature roughness lengths z0,q and z0,t. Using improved values for z0,m, z0,q and z0,t, recomputed bulk fluxes are compared to fluxes simulated by regional climate models MAR, RACMO2.3p2 and RACMO2.4p1 for the period from 2016 to 2020. We find an overall good agreement between the measured and modelled turbulent flux magnitudes for the summer period; however, all evaluated models simulate stronger near-surface temperature gradients during winter compared to observations from automatic weather stations, leading to consistently larger modelled SHF and LHF values in winter.Abstract
The latent (LHF) and sensible (SHF) heat fluxes are key components of the surface mass and energy balance in the accumulation area of the Greenland Ice Sheet, making them critical for accurate sea level projections. While Eddy-Covariance (EC) systems provide accurate measurements of the turbulent surface transport of mass and energy in the low and mid-latitudes, frequent stable boundary layer conditions in polar regions introduce uncertainties in the EC method. In addition, as EC measurements are sparse, it is critical to characterise biases in the more common bulk fluxes obtained from automatic weather stations and climate models in polar areas. In this study, we present an intercomparison of three independent EC systems from the 28 May until 31 July 2019 at the EastGRIP site at ∼ 2700 m a.s.l. on the Greenland Ice Sheet to assess the accuracy of LHF and SHF measurements. A comparison of the fluxes by the three systems demonstrates excellent agreement with an absolute bias of 0.2 W m−2 and slopes between 1.01 and 1.16 for the LHF, and an absolute bias of less than 0.5 W m−2 and slopes of 1.0 for the SHF. A comparison of the validated EC fluxes against the bulk method highlights the sensitivity to the site-specific roughness length z0,m and the limitation of common parameterisations of the humidity and temperature roughness lengths z0,q and z0,t. Using improved values for z0,m, z0,q and z0,t, recomputed bulk fluxes are compared to fluxes simulated by regional climate models MAR, RACMO2.3p2 and RACMO2.4p1 for the period from 2016 to 2020. We find an overall good agreement between the measured and modelled turbulent flux magnitudes for the summer period; however, all evaluated models simulate stronger near-surface temperature gradients during winter compared to observations from automatic weather stations, leading to consistently larger modelled SHF and LHF values in winter
Analysis of Path Losses on Terahertz Band for Non-Terrestrial Networks
No full textAbstract
With the ongoing evolution of global connectivity, the demand for reliable, high-speed communication links in scenarios such as in-flight internet and remote areas has intensified. As a result, research has increasingly focused on the millimeter wave (mmWave)/terahertz (THz) band in non-terrestrial networks (NTNs) due to its potential to support ultra-high data rates. To assess feasibility, this paper presents a comprehensive assessment of path losses and their impact on NTN links operating within the THz band. It examines key impairments affecting signal propagation, including atmospheric absorption and other atmospheric losses. A detailed investigation is conducted for different NTN scenarios across diverse geographical locations, primarily focusing on adverse weather conditions while also considering clear skies, with seasonal variations integrated to assess link reliability. The findings reveal that, for ground-to-space links, frequencies above 300 GHz experience significantly high losses, whereas for satellite-to-airborne links, frequencies up to 1000 GHz can be achieved.Abstract
With the ongoing evolution of global connectivity, the demand for reliable, high-speed communication links in scenarios such as in-flight internet and remote areas has intensified. As a result, research has increasingly focused on the millimeter wave (mmWave)/terahertz (THz) band in non-terrestrial networks (NTNs) due to its potential to support ultra-high data rates. To assess feasibility, this paper presents a comprehensive assessment of path losses and their impact on NTN links operating within the THz band. It examines key impairments affecting signal propagation, including atmospheric absorption and other atmospheric losses. A detailed investigation is conducted for different NTN scenarios across diverse geographical locations, primarily focusing on adverse weather conditions while also considering clear skies, with seasonal variations integrated to assess link reliability. The findings reveal that, for ground-to-space links, frequencies above 300 GHz experience significantly high losses, whereas for satellite-to-airborne links, frequencies up to 1000 GHz can be achieved
Using sulfuric acid-phosphoric acid leaching to remove aluminum and cathode material metal residues from spent graphite
No full textAbstract
Spent graphite (SG) separated in industrial-scale recycling of spent lithium-ion batteries (LIBs) usually contains various impurities, such as cathode material metals, aluminum, and organic contaminants. Therefore, the re-use of SG may require various purification and regeneration processes to meet battery-grade purity requirements. This study investigated the simultaneous removal of aluminum and cathode material metals (lithium, nickel, manganese, and cobalt) from LIB black mass-derived SG using a sulfuric acid–phosphoric acid mixture for leaching. The effects of phosphoric acid concentration (0–0.7 mol L−1) and reaction time (240–600 min) were evaluated. Cathode material metals were removed with sulfuric acid leaching (97.5–98.9%), but aluminum impurities remained almost completely in the SG (aluminum removal: 17.8%). The simultaneous removal of the studied elements was achieved by a sulfuric acid–phosphoric acid mixture. The removal of studied elements was significantly enhanced by increasing phosphoric acid concentration from 0.1 mol L−1 to 0.5 mol L−1 and by increasing reaction time from 240 min to 600 min. Under the studied conditions (sulfuric acid: 2.75 mol L−1; phosphoric acid: 0.5 mol L−1; time: 600 min; temperature: 100 °C; L/S ratio: 10 mL g−1), aluminum removal was increased to 90.8%, while cathode material metals were removed between 97.7% and 99.5%. The carbon content of the SG sample notably increased from 69.2 to 93.0 wt% with this single-stage acid mixture leaching process. Based on thermogravimetric and X-ray photoelectron spectroscopy analyses, residual impurities in the purified SG sample consisted mostly of organic or other volatile impurities. In addition, lithium phosphate, produced as a side stream in lithium processing, was also examined as an alternative phosphate source in the acid mixture to replace phosphoric acid. Based on the results, the sulfuric acid–lithium phosphate mixture showed equal capability for aluminum and cathode material metal removal to the sulfuric acid–phosphoric acid mixture, increasing carbon content up to 92.3 wt%. This offers a potential application for further lithium phosphate use. The results of this study showed that a sulfuric acid–phosphoric acid mixture has a good capability to purify SG, and side stream-based lithium phosphate can replace phosphoric acid in the mixture.Abstract
Spent graphite (SG) separated in industrial-scale recycling of spent lithium-ion batteries (LIBs) usually contains various impurities, such as cathode material metals, aluminum, and organic contaminants. Therefore, the re-use of SG may require various purification and regeneration processes to meet battery-grade purity requirements. This study investigated the simultaneous removal of aluminum and cathode material metals (lithium, nickel, manganese, and cobalt) from LIB black mass-derived SG using a sulfuric acid–phosphoric acid mixture for leaching. The effects of phosphoric acid concentration (0–0.7 mol L−1) and reaction time (240–600 min) were evaluated. Cathode material metals were removed with sulfuric acid leaching (97.5–98.9%), but aluminum impurities remained almost completely in the SG (aluminum removal: 17.8%). The simultaneous removal of the studied elements was achieved by a sulfuric acid–phosphoric acid mixture. The removal of studied elements was significantly enhanced by increasing phosphoric acid concentration from 0.1 mol L−1 to 0.5 mol L−1 and by increasing reaction time from 240 min to 600 min. Under the studied conditions (sulfuric acid: 2.75 mol L−1; phosphoric acid: 0.5 mol L−1; time: 600 min; temperature: 100 °C; L/S ratio: 10 mL g−1), aluminum removal was increased to 90.8%, while cathode material metals were removed between 97.7% and 99.5%. The carbon content of the SG sample notably increased from 69.2 to 93.0 wt% with this single-stage acid mixture leaching process. Based on thermogravimetric and X-ray photoelectron spectroscopy analyses, residual impurities in the purified SG sample consisted mostly of organic or other volatile impurities. In addition, lithium phosphate, produced as a side stream in lithium processing, was also examined as an alternative phosphate source in the acid mixture to replace phosphoric acid. Based on the results, the sulfuric acid–lithium phosphate mixture showed equal capability for aluminum and cathode material metal removal to the sulfuric acid–phosphoric acid mixture, increasing carbon content up to 92.3 wt%. This offers a potential application for further lithium phosphate use. The results of this study showed that a sulfuric acid–phosphoric acid mixture has a good capability to purify SG, and side stream-based lithium phosphate can replace phosphoric acid in the mixture
Visual Perception and Fine Motor Skills Mediate Effects of Very Preterm Birth on Visual-Motor Integration
No full textAbstract
Aim:
The developmental profile underlying visual-motor difficulties in very preterm children (< 32 weeks gestation) remains unclear. The aim is to test whether visual perception and fine motor skills mediate effects of very preterm birth on visual-motor integration before school entry.
Methods:
60 very preterm and 60 term children were assessed at age 5–6 years with the Movement Assessment Battery for Children and the Developmental Test of Visual Perception. Direct and indirect effects of very preterm birth, visual perception and fine motor performance on visual-motor integration were tested using mediation analysis with SPSS.
Results:
Mediation hypothesis was confirmed, specifically: (I) very preterm birth was associated with low visual-motor integration, fine motor skills and visual perception (β = −0.46, β = −0.44, β = −0.25, p < 0.01, respectively). (II) Fine motor skills and visual perception were positively associated with visual motor skills (β = 0.62, β = 0.43, p < 0.001). (III) In the full mediation model, the direct association of very preterm birth with visual motor integration was partially mediated by fine motor skills (β = −0.39, p < 0.001) and visual perception (β = −0.12, p < 0.001).
Conclusion:
Effects of very preterm birth on visual-motor integration are partially mediated by fine motor skills and visual perception. This developmental profile should be considered in screening and follow-up assessments.
Trial Registration:
German clinical trial register number: DRKS00011503Abstract
Aim:
The developmental profile underlying visual-motor difficulties in very preterm children (< 32 weeks gestation) remains unclear. The aim is to test whether visual perception and fine motor skills mediate effects of very preterm birth on visual-motor integration before school entry.
Methods:
60 very preterm and 60 term children were assessed at age 5–6 years with the Movement Assessment Battery for Children and the Developmental Test of Visual Perception. Direct and indirect effects of very preterm birth, visual perception and fine motor performance on visual-motor integration were tested using mediation analysis with SPSS.
Results:
Mediation hypothesis was confirmed, specifically: (I) very preterm birth was associated with low visual-motor integration, fine motor skills and visual perception (β = −0.46, β = −0.44, β = −0.25, p < 0.01, respectively). (II) Fine motor skills and visual perception were positively associated with visual motor skills (β = 0.62, β = 0.43, p < 0.001). (III) In the full mediation model, the direct association of very preterm birth with visual motor integration was partially mediated by fine motor skills (β = −0.39, p < 0.001) and visual perception (β = −0.12, p < 0.001).
Conclusion:
Effects of very preterm birth on visual-motor integration are partially mediated by fine motor skills and visual perception. This developmental profile should be considered in screening and follow-up assessments.
Trial Registration:
German clinical trial register number: DRKS0001150
Iron based sulfate cathodes in sodium ion batteries
No full textRautapohjaiset sulfaatit ovat herättäneet tutkijoiden kiinnostuksen natriumioniakkujen elektrodimateriaaleina muun muassa korkean käyttöpotentiaalin ja hyvän teoreettisen kapasiteetin takia. Rautapohjaisista sulfaateista tutkituin on Na2Fe2(SO4)3, jolla teoreettinen kapasiteetti on 120 mAh/g ja käyttöpotentiaali on 3,8 V. Rautapohjaisten sulfaattien synteesit suoritetaan alhaisissa lämpötiloissa, sillä lähtöaineiden sulfaatti-ionit hajoavat yli 450 °C:ssa. Synteesin ensimmäinen vaihe on lähtöaineiden sekoitus, joka voidaan tehdä kiintessä olomuodossa jauhamalla tai nesteissä esimerkiksi ruiskukuivauksella. Lähtöaineiden sekoituksen jälkeen voidaan suorittaa materiaalin mukaan sopiva loppulämmitys.
Rautapohjaisten sulfaattien suurin heikkous on heikko sähkönjohtavuus, joka johtaa kapasiteetin laskuun suuremmilla lataus-purkausnopeuksilla (engl C-rate, käytetään tässä tutkielmassa C-arvo). Rautapohjaisten sulfaattien syklinen vakaus on myös heikko ja kapasiteetti laskee usein jo kymmenien syklien aikana huomattavasti. Materiaalien ominaisuuksia on kuitenkin pyritty kehittämään useilla keinoilla. Rautapohjaisiin sulfaatteihin on esimerkiksi muodostettu johtava hiiliverkosto tai pinnoite. Rautapohjaisia sulfaatteja on myös doupattu magnesiumilla ja fosfaatilla ja doupattuun materiaaliin on yhdistetty lisäksi hiilipinnoite. Hiilikomposiittien muodostuksella syklinen vakaus on saatu nousemaan jopa kymmeniin tuhansiin sykleihin ja douppauksella kapasiteetti saatu pysymään korkeana jopa C-arvolla 100
Microfluidic Electro-Viscoelastic Separation of Submicron Particles and Extracellular Vesicles
No full textAbstract
Isolating submicron and nanoparticles in microfluidics is challenging due to weak separation forces and dominance of diffusion at the nanoscale. While the unfavorable scaling of the separation forces can be addressed by nanofluidic systems, the operation of such systems faces several limitations such as low throughput, high pressure requirements, and clogging. To overcome these issues, we present electro-viscoelastic particle separation─a method combining electrophoretic slip-induced lift with viscoelastic microfluidics to enhance lateral forces on nanoparticles. Using a standard microchannel (60 μm height, 20 μm width, and 3 cm length), we demonstrated fractionation of a mixture of submicron polystyrene particles with different sizes in a viscoelastic medium under an applied electric field. This system improved the purity of 50, 200, and 500 nm particles by 39%, 29%, and 50%, respectively. We further applied this technique to purify cancer cell–secreted extracellular vesicles (EVs) from background nanoscale contaminants such as soluble proteins, achieving a 22% increase in EV purity. Notably, our platform operates at blockage ratios as low as 0.002, which is a considerable improvement over its inertial and viscoelastic counterparts. These experimental findings highlight the potential of integrating electric fields with viscoelastic migration for effective nanoparticle separation. A comparison of our results with state-of-the-art theoretical models of electro-viscoelastic migration (EVM) suggests that the current understanding requires further advancement. Nevertheless, the enhanced electro-viscoelastic lift predicted by these models underscores the prospect of this technique for separation of bionanoparticles.Abstract
Isolating submicron and nanoparticles in microfluidics is challenging due to weak separation forces and dominance of diffusion at the nanoscale. While the unfavorable scaling of the separation forces can be addressed by nanofluidic systems, the operation of such systems faces several limitations such as low throughput, high pressure requirements, and clogging. To overcome these issues, we present electro-viscoelastic particle separation─a method combining electrophoretic slip-induced lift with viscoelastic microfluidics to enhance lateral forces on nanoparticles. Using a standard microchannel (60 μm height, 20 μm width, and 3 cm length), we demonstrated fractionation of a mixture of submicron polystyrene particles with different sizes in a viscoelastic medium under an applied electric field. This system improved the purity of 50, 200, and 500 nm particles by 39%, 29%, and 50%, respectively. We further applied this technique to purify cancer cell–secreted extracellular vesicles (EVs) from background nanoscale contaminants such as soluble proteins, achieving a 22% increase in EV purity. Notably, our platform operates at blockage ratios as low as 0.002, which is a considerable improvement over its inertial and viscoelastic counterparts. These experimental findings highlight the potential of integrating electric fields with viscoelastic migration for effective nanoparticle separation. A comparison of our results with state-of-the-art theoretical models of electro-viscoelastic migration (EVM) suggests that the current understanding requires further advancement. Nevertheless, the enhanced electro-viscoelastic lift predicted by these models underscores the prospect of this technique for separation of bionanoparticles
80 years of extracellular vesicles: from discovery to clinical translation
No full textAbstract
Extracellular vesicles (EVs) are heterogeneous, lipid bilayer-enclosed vesicles secreted by cells. Research on EVs dates back to the 1940s, and the term “exosomes” - a major subtype of EVs - was coined in 1981 to describe small membrane vesicles shed from cells. However, it is only in the past two decades that research in this area has expanded rapidly. By transferring functional biomolecules, EVs play a pivotal role in intercellular communication and regulate a wide range of cellular functions under both physiological and pathological conditions. Owing to their high biocompatibility, capacity to protect encapsulated cargo from degradation, and ability to cross biological barriers, EVs also show great promise as biomarkers and drug-delivery systems. Following the first, albeit unintentional, isolation of EVs in 1946, the 80th anniversary of EV research is now approaching. In this review, we trace the history of EV research and summarize key advances in the field. We also discuss current challenges and future prospects in this rapidly evolving area.Abstract
Extracellular vesicles (EVs) are heterogeneous, lipid bilayer-enclosed vesicles secreted by cells. Research on EVs dates back to the 1940s, and the term “exosomes” - a major subtype of EVs - was coined in 1981 to describe small membrane vesicles shed from cells. However, it is only in the past two decades that research in this area has expanded rapidly. By transferring functional biomolecules, EVs play a pivotal role in intercellular communication and regulate a wide range of cellular functions under both physiological and pathological conditions. Owing to their high biocompatibility, capacity to protect encapsulated cargo from degradation, and ability to cross biological barriers, EVs also show great promise as biomarkers and drug-delivery systems. Following the first, albeit unintentional, isolation of EVs in 1946, the 80th anniversary of EV research is now approaching. In this review, we trace the history of EV research and summarize key advances in the field. We also discuss current challenges and future prospects in this rapidly evolving area
Operationalizing mission statements for sustainability through product portfolio and lifecycle management
No full textAbstract
Organizations increasingly articulate sustainability commitments in their mission statements, yet frequently struggle to translate these commitments into concrete product portfolio and lifecycle decisions. Prior research has largely examined mission statements as symbolic, communicative, or legitimacy-oriented devices, offering limited explanation of how sustainability intent is operationalized within product-related governance.
This study does not argue that mission statements merely include sustainability; rather, it explains how mission statements function as governance mechanisms that transmit, translate, and render sustainability decision-making traceable across product portfolios and lifecycles. Drawing on a PRISMA-informed, concept-driven systematic literature review, we synthesize research at the intersection of mission statements, sustainability, and product management to develop a novel conceptual framework grounded in Product Portfolio Management (PPM) and Product Lifecycle Management (PLM).
The framework explains how sustainability intent articulated in mission statement components is transmitted into portfolio-level prioritization, translated into lifecycle-level product decisions, and made traceable and measurable through structured product data, product structures, and productization logic. Rather than treating mission statements as symbolic declarations, the framework positions them as an upstream governance layer that connects corporate vision with portfolio governance and lifecycle execution.
By clarifying the mechanisms through which mission statements influence sustainable product decisions, this study advances theory on mission-driven sustainability governance and provides a foundation for future empirical testing within PPM and PLM contexts.Abstract
Organizations increasingly articulate sustainability commitments in their mission statements, yet frequently struggle to translate these commitments into concrete product portfolio and lifecycle decisions. Prior research has largely examined mission statements as symbolic, communicative, or legitimacy-oriented devices, offering limited explanation of how sustainability intent is operationalized within product-related governance.
This study does not argue that mission statements merely include sustainability; rather, it explains how mission statements function as governance mechanisms that transmit, translate, and render sustainability decision-making traceable across product portfolios and lifecycles. Drawing on a PRISMA-informed, concept-driven systematic literature review, we synthesize research at the intersection of mission statements, sustainability, and product management to develop a novel conceptual framework grounded in Product Portfolio Management (PPM) and Product Lifecycle Management (PLM).
The framework explains how sustainability intent articulated in mission statement components is transmitted into portfolio-level prioritization, translated into lifecycle-level product decisions, and made traceable and measurable through structured product data, product structures, and productization logic. Rather than treating mission statements as symbolic declarations, the framework positions them as an upstream governance layer that connects corporate vision with portfolio governance and lifecycle execution.
By clarifying the mechanisms through which mission statements influence sustainable product decisions, this study advances theory on mission-driven sustainability governance and provides a foundation for future empirical testing within PPM and PLM contexts
Multivariate analysis on simulated moisture damage emission to indoor air
No full textAbstract
Moisture damage in buildings is a significant source of indoor air problems, releasing e.g. volatile organic compounds (VOCs) and microbially produced VOCs (MVOCs), which can cause unpleasant odors and health symptoms. However, interpreting MVOCs as indicators of mold is challenging due to their various sources and limitations in analytical methods.
The objective of this study was to identify the most critical factors influencing VOC emissions from moisture-damaged wall structures into the indoor environment via structural air leakages. The research was conducted using the VTT Indoor Air Quality (IAQ) Simulator and analyzed with Principal Component Analysis (PCA). The IAQ simulator was used to investigate the transport of airborne impurities from mold-contaminated wall structures in realistic building conditions and the systematic manipulation of key environmental parameters. The resulting dataset was subjected to multivariate analysis to identify the most influential factors contributing to IAQ degradation in moisture-damaged structures.
The key conclusions revealed that material relative humidity was the most significant single factor affecting all VOC concentrations; higher humidity consistently increased emissions. Four specific ketones (2-pentanone, 2-hexanone, 2-heptanone, and 2-octanone) were clearly identified as originating from microbial growth, with their concentrations being significantly higher in the presence of active mold growth. Pressure differentials had only a borderline effect on gypsum board emissions, while the insulation layer showed no significant impact on any of the identified VOC components. These findings underscore the critical role of relative humidity in determining indoor VOC profiles and highlight the value of multivariate methods in assessing mold-related indoor air problems.Abstract
Moisture damage in buildings is a significant source of indoor air problems, releasing e.g. volatile organic compounds (VOCs) and microbially produced VOCs (MVOCs), which can cause unpleasant odors and health symptoms. However, interpreting MVOCs as indicators of mold is challenging due to their various sources and limitations in analytical methods.
The objective of this study was to identify the most critical factors influencing VOC emissions from moisture-damaged wall structures into the indoor environment via structural air leakages. The research was conducted using the VTT Indoor Air Quality (IAQ) Simulator and analyzed with Principal Component Analysis (PCA). The IAQ simulator was used to investigate the transport of airborne impurities from mold-contaminated wall structures in realistic building conditions and the systematic manipulation of key environmental parameters. The resulting dataset was subjected to multivariate analysis to identify the most influential factors contributing to IAQ degradation in moisture-damaged structures.
The key conclusions revealed that material relative humidity was the most significant single factor affecting all VOC concentrations; higher humidity consistently increased emissions. Four specific ketones (2-pentanone, 2-hexanone, 2-heptanone, and 2-octanone) were clearly identified as originating from microbial growth, with their concentrations being significantly higher in the presence of active mold growth. Pressure differentials had only a borderline effect on gypsum board emissions, while the insulation layer showed no significant impact on any of the identified VOC components. These findings underscore the critical role of relative humidity in determining indoor VOC profiles and highlight the value of multivariate methods in assessing mold-related indoor air problems