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Property Variations of Binder-Free Lignin-Rich Fiber Networks Driven by Forming Processes and Hot Pressing
No full textSheets made from lignin-rich fiber raw materials can be bonded by hot pressing without external binders. This paper explores how air-laid, foam-laid, and water-laid web formation methods, initial sheet moisture content, as well as hot-pressing conditions (5 MPa, 100–260 °C, 1–60 s), impact the physical properties of board-like materials made of chemi-thermomechanical softwood fibers. In addition to the structural characterization of the hot-pressed materials by X-ray microtomography, air permeance, water contact angle, dry and wet tensile strength, and in-plane compression properties were measured. Despite the significant structural densification, characteristics of the forming method were retained after hot pressing in the final sheet properties. The compressed air-laid sheets had the highest air permeance and the smallest mean pore size, which could be beneficial for particle filtering. At moderate pressing temperatures and times, the significant proportion of large pores in the foam-laid sheets made them weaker than the corresponding water-laid sheets. However, under extreme pressing conditions, the foam- and water-laid sheets reached similar values of high tensile and in-plane compression strength. This suggests that polymer interdiffusion becomes the dominant factor for material strength under these conditions, superimposing the hydrogen bonding created during aqueous forming
Unexpected low temperature crack propagation in nuclear post-shutdown water chemistry of Alloy 52 with potential effects of hydrogen
Get PDFConstant-displacement bolt-loaded compact tension specimens of Nickel-based Alloy 52 were exposed to boiling water reactor environment for 12 years, followed by an additional 3 years in post-shutdown cold water conditions in a Swedish nuclear power plant test loop, under a stress intensity factor of 20 MPa√m. After outer surface decontamination and specimen opening, unexpected crack extensions of 3–4.5 mm were observed. The fracture surface and the cross-sectional deformation microstructure were examined by electron microscopies techniques down to the nanoscale. The oxide layer in the region exhibiting unexpected crack growth was notably thin, suggesting that it formed after exposure to elevated operating temperatures. The dominant fracture mode is transgranular, propagating along close-packed {111} planes. The grains contained heterogeneous microstructures with regions enriched in nanometer-sized Ti(N,C) and the zigzag crack paths did not traverse these regions strengthened areas. Extensive shear bands were present near the crack tips, indicating pronounced localized plasticity. Hydrogen reduces stacking fault energy, results in localized plasticity and enhances shear bands formation. Low temperature crack propagation with evident effects of hydrogen was considered as the potential cause of crack propagation in Alloy 52 in the absence of external dynamic loading under post-shutdown cold water chemistry
A Framework for Road Authorities to Assess Their Readiness to Support Connected and Automated Driving
No full textConnected and Automated Driving (CAD) will bring disruption to individuals, economies, and society. Most forms of CAD require some level of support from the infrastructure for their safe operation, in particular communications. However, additional infrastructure services to support CAD could improve safety and robustness and bring further benefits such as increased capacity. However, the infrastructure requirements of vehicle Original Equipment Manufacturers (OEMs) are not always clear, and it is therefore difficult for National Road Authorities (NRA) to prepare future levels of support for CAD, given rapidly evolving technology and uncertain projections of future CAD demand. There is a need to articulate those requirements, bringing stakeholders together to formulate a structured approach, and a roadmap that will advance safe and smart roads that support CAD. This paper presents the DiREC project (consortium partners: TRL, ARUP, TU Delft, VTT, VTI and FEHRL) funded by the CEDR Transnational Road Research Programme Call 2020 with funding provided by CEDR members of Belgium (Flanders), Denmark, Ireland, Israel, Netherlands, Norway, Sweden, Switzerland and the United Kingdom. DiREC is seeking to address the above challenge. The project has established a CAV-Readiness Framework (CRF) based on a level of service approach to understand the needs of CAD, and to define the infrastructure and services that NRAs could provide to support these needs.</p
Mineral carbonation:Thermal activation of serpentine as flexible component in energy systems
No full textIn this article, the thermal activation of serpentine for mineral carbonation using an electrically heated fluidised bed was studied. This process step is combined into a novel process configuration with rapid thermal activation and a thermal energy storage. For the studied serpentinite mine tailings, the thermal activation durations corresponding with desired mineralogical changes were ' 2 min at 700 °C, 4–8 min at 650 °C, 16–75 min at 600 °C and ' 75 min at 550°C, improving reaction kinetics compared to chamber furnace processing at 650°C for 30 min or 750 °C for 15 min. In all fluidised bed experiments, the preferred mineralogical changes corresponded to a dehydroxylation degree of 52–72 % determined with simultaneous thermal analysis. Fourier-transform infrared analyser was used for online determination of the dehydroxylation degree and could be used for process control if the measurement delay was considered better. The mass and energy balances for an industrial-scale thermal activation plant matching 100,000 tCO2/a storage were calculated. The average electrical power demand was 17.4 MW, of which 22.9 % was recovered from steam and 61.7 % was stored in the thermal energy storage silos. Twelve-hour and 7-day buffering times resulted in silo volumes of 452.5 m3 and 3167 m3 and thermal energy storage capacities of 129.0 MWh and 903.2 MWh, respectively. Further studies should include process parameter optimisation as well as techno-economic and life cycle assessments to holistically improve the concept.</p
Europe-wide maps of biomass density based on satellite remote sensing data for 2017, 2020, 2021 and 2023
No full textSpatially explicit information on forest structure and biomass is needed to meet the monitoring and reporting requirements of several European policies. Satellite images enable mapping and monitoring of the Europe’s forest resources through operational observations from the Sentinel-1 Synthetic Aperture Radar (SAR) and the Advanced Land Observing Satellite 2 (ALOS-2) Phased Array l -band SAR 2 (PALSAR-2) instruments. Data acquired in 2017, 2020, 2021 and 2023 were used to generate annual maps of forest biomass variables, namely Growing Stock Volume (GSV), Aboveground Biomass (AGB) and Belowground Biomass (BGB), with a pixel size of 20 m × 20 m. All products are in the geometry of the Sentinel-2 tiling system. A spatially averaged map with a pixel size of 100 m × 100 m (1 hectare) in geographic projection is also supplied, for users who do not require the highest spatial resolution. The maps were generated with a fully documented processing chain that includes (i) pre-processing of the SAR data to create stacks of co-registered terrain geocoded images of the backscattered intensity and (ii) inversion of a physically-based model to estimate GSV. AGB and BGB were subsequently estimated using allometric relationships. Per-pixel standard deviations were computed for each biomass variable by propagating uncertainties from both the SAR observations and the model parameters. The maps clearly reproduce the expected spatial patterns of forest biomass across Europe and provide sufficient spatial detail to identify biomass dynamics related to, e.g., logging and regrowth. Validation against measurements collected by National Forest Inventories (NFIs) indicates poor agreement with map values at the pixel scale, with errors larger than 50% of the reference biomass. The correspondence substantially improved for spatial aggregates, such as administrative units, for which the bias was mostly negligible and the mean square error was below 30% of the reference value. The number of ALOS-2 PALSAR-2 images affected the inter-annual consistency of the maps, which was lower in regions with only one or two observations per year.</p
Assessment of soil impacts from lead release by lead-halide perovskite solar cells based on outdoor leaching tests
No full textPerovskite solar cells represent a promising technology in the photovoltaic industry due to their high power conversion efficiency, potential for cost-effective manufacturing and versatile applications. The most stable and efficient perovskites to date rely on lead (Pb), raising concerns about leaching into the environment; however Pb release so far has only been quantified under laboratory conditions, and no field-based assessment under real outdoor expsosure has yet evaluated this risk. The present study quantified Pb leaching from various metal-halide perovskite compositions, device stacks and encapsulation approaches in a rooftop installation for up to 9 months. Pb leaching was low across all tested configurations, even in intentionally damaged materials. Glass–glass encapsulated tandem devices shattered by hail and plastic-encapsulated samples damaged by 100 µm pinholes released only 0.07% ± 0.01% and 0.15% ± 0.14% of their initial Pb, respectively, likely due to the slow diffusion of Pb cations in water. The highest leaching (4.81% ± 0.02%) occurred in unlaminated laboratory devices, demonstrating the importance of proper lamination. A self-developed freeware web tool was used to calculate predicted soil concentrations and evaluate potential impacts. Even for unlaminated devices, concentrations would only slightly exceed natural background levels (5.6 mg kg−1 increase), with negligible effects on soil fertility. A hypothetical worst-case scenario assuming a 1000 nm thick perovskite layer and complete Pb leaching onto a narrow strip of soil predicted a negative impact on soil fertility; however remediation would still not be required under Swiss environmental regulations. Overall, current industry-standard encapsulation limits Pb leaching to levels that almost completely mitigate negative impacts on soil health.</p
A Scots pine 4-coumarate:CoA ligase with high cinnamic acid affinity is the primary candidate for pinosylvin biosynthesis
No full textPinosylvin and its derivatives are defense-related stilbenoids that contribute to pathogen and decay resistance of Scots pine (Pinus sylvestris L.) heartwood. While most enzymes in the pinosylvin biosynthesis pathway in Scots pine have been identified, the enzyme responsible for activating cinnamic acid to cinnamoyl-CoA, an essential precursor for pinosylvin biosynthesis, has remained unknown. In this study, we explored Scots pine transcriptomic data to observe the expression profiles of the 4-coumarate:CoA ligase (4CL) genes and produced the enzymes in Nicotiana benthamiana to assay their kinetic properties. We identified and characterized four 4CL isoforms, one of which (Ps4CL2) was both co-expressed with pinosylvin biosynthesis genes under stilbene-inducing conditions and exhibited an unusually high affinity for cinnamic acid surpassing that of previously characterized cinnamate-activating 4CLs. Through site-directed mutagenesis and domain-swapping experiments with the closely related Ps4CL3, we showed that substrate preference in Ps4CL2 results from multiple interacting regions within the enzyme. Our findings establish Ps4CL2 as the prime candidate for cinnamate activation as the last missing enzyme for pinosylvin biosynthesis in Scots pine and provide insight into enzyme specialization within the 4CL family.</p
Pienydinvoiman luvitus ja turvallisuuden varmistaminen.:Pieni opas kuntien päätöksenteon ja hankkeiden valmistelun tueksi.
No full textPienydinvoima on uusi vaihtoehto kunnille hiilineutraalin energian tuotantoon. Pienydinvoimaa voidaan reaktorityypistä ja kapasiteetista riippuen käyttää joko kaukolämmön, sähkön tai molempien tuotantoon. Tämä asettaa kunnat ja kuntien energiayhtiöt usein uuteen tilanteeseen, jossa hankkeen kehityksessä on huomioitava tavallisia rakennushankkeita ohjaavien vaatimusten lisäksi ydinenergialaista tulevat vaatimukset laitoksen paikanvalinnalle ja luvitukselle. Tämän pikkuoppaan tarkoitus on auttaa kuntia, kuntien päätöksentekijöitä ja tulevia hankekehittäjiä ymmärtämään paremmin pienydinvoimalaitoshankkeisiin liittyviä ominaispiirteitä ja mitä asioita kannattaa ottaa huomioon hankkeen edetessä. Tätä opasta kirjoittaessa sekä ydinenergialakia ja alueidenkäyttölakia on uudistettu ja oppaassa esitetyt kaavoitukseen ja ydinenergialain mukaiseen luvitukseen liittyvät tiedot perustuvat näiden lakien luonnoksiin. Tästä syystä ajantasaiset tiedot ja viranomaisohjeet tulee aina varmistaa lisäksi suoraan vastuussa olevilta viranomaisilta. Tätä opasta voidaan kuitenkin käyttää esitietona hankkeiden valmistelun ja päätöksenteon tueksi. Hankkeiden ydinenergialain mukainen luvitus etenee vaiheittain sisältäen ydinlaitoksen periaatepäätöksen, rakentamisluvan ja käyttöluvan. Lisäksi pienydinvoimalaitoshanke vaatii ympäristövaikutusten arvioinnin (YVA on vaatimus rakentamisluvalle ja SOVA on osa periaatepäätöstä) sekä muita lupia. Paikanvalinnassa ja kaavoituksessa on huomioitava kullekin ydinvoimalaitokselle erikseen määritelty riittävän suuri suojavyöhyke, varautumisalue, paikkaan liittyvät riskit ja muut etukäteen määritellyt pakanvalintakriteerit, kuten esimerkiksi etäisyys sähkö- tai kaukolämpöverkkoon. Soveltuvien sijaintipaikkojen kartoitus, vertailu ja lopullinen paikanvalinta suositellaan tekemään vaiheittain. Luvanhakijan vastuu korostuu hankkeeseen liittyvien tarpeellisten selvitysten teettämisessä. Säteilyturvakeskus (STUK) arvioi tehtyjen selvitysten perusteella täyttääkö sijaintipaikka sille asetetut ydinenergialain mukaiset vaatimukset.Pienydinvoimalaitoshankkeilla on useita mahdollisia organisoitumismalleja. Merkittävää hankkeen kannalta on hankekehittäjän ja erityisesti luvanhakijan ydinenergiaan liittyvä osaaminen, hyvä turvallisuuskulttuuri, pitkäaikainen sitoutuminen ja riittävän hyvät taloudelliset resurssit. Luvanhakijana voi olla esimerkiksi kunnan energiayhtiö, suurempi konsortio tai valtakunnallinen energiayhtiö/palveluntuottaja. Ydinvoimalaitoksen operaattori voisi olla myös erillinen toimija, joka vastaa reaktorin turvallisesta käytöstä. Omistajina voi olla esimerkiksi kunta, kuntayhtymä tai energiayhtiö. Reaktorin toimittaja vastaa myymästään reaktoritekniikasta. Luvanhakija on vastuussa myös ydinjätehuollon järjestämisestä ja siihen liittyvistä kustannuksista. Ydinjätehuolto voidaan järjestää joko luvanhakijan toimesta tai jätehuoltovelvollisuus voidaan tietyin ehdoin ja kaupallisin sopimuksin siirtää toiselle osapuolelle. Erityisesti käytetyn ydinpolttoaineen ja korkea-aktiivisen jätteen osalta keskitetty ydinjätehuolto on suositeltavaa riittävän asiantuntemuksen ja osaamisen varmistamiseksi. Ydinvoiman käyttö edellyttää, että ydinvoimalaitos on suunniteltu turvalliseksi, sen käyttö on turvallista ja että laitoksella on toimivat suunnitelmat valmiustilanteita varten. Ydinvoiman käyttö kunnissa tulee olla myös sosiaalisesti hyväksyttävää. Tämä tarkoittaa, että luvanhaltija ja kunta sekä tiedottavat hankkeen valmistelusta ja etenemisestä mahdollisimman avoimesti ja kattavasti että mahdollistavat kuntalaisten osallistumisen, vuoropuhelun ja vaikutusmahdollisuudet läpi hankevalmistelun ja laitoksen koko elinkaaren. Pienydinvoiman kannatus Suomessa on tällä hetkellä pääsääntöisesti hyvällä tasolla ja myös asukaskyselyn perusteella kaupunkilaisten enemmistö suhtautuu myönteisesti pienydinvoimaan. Hyväksyntä kuitenkin heikkenee sijoitettaessa voimaloita omaan kuntaan ja erityisesti lähiympäristöön. Turvallisuuskäsitykset ja ydinjätehuollon ratkaisut jakavat mielipiteitä, ja päätöksenteolta toivotaan avointa viestintää ja osallistavia toimintatapoja. Ydinjätehuollon osalta tarvitaan lisää tiedotusta ja keskustelua jätehuollon järjestämisen eri vaihtoehdoista. <br/
Qualification of affordable open-source analog and digital Sun sensors for CubeSats
No full textThis paper presents the qualification of affordable, open-source analog (PSS) and digital Sun sensors (DSS) for CubeSats, which aim to provide cost-effective and accessible attitude determination solutions for small satellite missions. The study evaluates the performance, reliability, and suitability of these sensors in space-like conditions, addressing key factors such as accuracy, thermal stability, and radiation tolerance. Experimental results demonstrate that the PSS can achieve better than 5° precision over a field of view of 100° while maintaining low costs and power consumption. The DSS shows a precision better than 0.5° over a field of view of 36° using a photolithographically patterned optical aperture acting as a pinhole. The research highlights the potential of these sensors to democratize access to space technology, supporting academic and commercial CubeSat missions with accessible and effective attitude determination solutions