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Polyetherureas as aqueous binders for Li ion batteries
No full textFunding: This research is funded by a UKRI Future Leaders Fellowship (MR/W007460/1) and an EPSRC grant (EP/Y005449/1). ABN acknowledges EP/T019298/1 for SEM studies.We report here the application of polyetherureas as a new class of aqueous binder for the LiFePO4 positive electrode material in lithium-ion batteries. Polyetherureas have been synthesized by ruthenium-catalyzed dehydrogenative coupling of polyethylene glycol diamine and methanol avoiding conventionally used toxic diisocyanate feedstock. The best binder performance was obtained when polyetherurea was used in combination with SBR (Styrene–Butadiene Rubber), exhibiting a coulombic efficiency of ∼99.9% and a cell polarization of 30 mV. Remarkably, the combination of polyetherurea/SBR as a binder demonstrates comparable performance as that of CMC (carboxymethyl cellulose), which is a commonly used aqueous binder for lithium-ion batteries. Evidence of the involvement of polyetherureas in binder performance has been provided using IR spectroscopy and scanning electron microscopy. Physical, electrochemical, and mechanical properties of the polyetherurea have been studied using TGA, DSC, powder XRD, cyclic voltammetry, nanoindentation, tensile testing, and 180° peel test that shed light on why this polymer acts as a good binder.Peer reviewe
Discovery of an accretion burst in a free-floating planetary-mass object
No full textFunding: V.A.A. acknowledges support from the INAF grants 1.05.12.05.03 and 1.05.24.07.02. A.S. and B.D. acknowledge support from the UKRI Science and Technology Facilities Council through grant ST/Y001419/1/. A.B. acknowledges support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy—EXC 2094—390783311. K.M. acknowledges support from the Fundação para a Ciência e a Tecnologia (FCT) through the grant 2022.03809.CEECIND. P.P. acknowledges funding from the UK Research and Innovation (UKRI) under the UK government’s Horizon Europe funding guarantee from ERC (under grant agreement No. 101076489).We report the discovery of a long-lasting burst of disk accretion in Cha J11070768-7626326 (Cha 1107-7626), a young, isolated, 5–10 MJupiter object. In spectra taken with XSHOOTER at ESO’s Very Large Telescope as well as NIRSpec and MIRI on the James Webb Space Telescope, the object transitions from quiescence in 2025 April–May to a strongly enhanced accretion phase in 2025 June–August. The line flux changes correspond to a 6–8-fold increase in the mass accretion rate, reaching 10−7 MJupiteryr−1, the highest measured in a planetary-mass object. During the burst, the Hα line develops a double-peaked profile with redshifted absorption, as observed in stars and brown dwarfs undergoing magnetospheric accretion. The optical continuum increases by a factor of 3–6; the object is ∼1.5–2 mag brighter in the R band during the burst. Mid-infrared continuum fluxes rise by 10%–20%, with clear changes in the hydrocarbon emission lines from the disk. We detect water vapour emission at 6.5–7 μm, which were absent in quiescence. By the end of our observing campaign, the burst was still ongoing, implying a duration of at least 2 months. A 2016 spectrum also shows high accretion levels, suggesting that this object may undergo recurring bursts. The observed event is inconsistent with typical variability in accreting young stars and instead matches the duration, amplitude, and line spectrum of an EXor-type burst, making Cha1107-7626 the first substellar object with evidence of a potentially recurring EXor burst.Peer reviewe
Spectroscopic substellar initial mass function of NGC 2244
No full textFunding: V.A-A., K.M. and K.K. acknowledge funding by the Science and Technology Foundation of Portugal (FCT), grants No. IF/00194/2015, PTDC/FIS-AST/28731/2017, UIDB/00099/2020, SFRH/BD/143433/2019 and PTDC/FIS-AST/7002/2020. R.S. acknowledges financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV-2017-0709) and financial support from national project PGC2018-095049-B-C21 (MCIU/AEI/FEDER, UE).Context . The dominant formation channel of brown dwarfs (BDs) is not well constrained yet and a promising way to discriminate between scenarios is to test the environment-dependent efficiency in forming BDs. So far, the outcome of star formation, studied through the initial mass function, has been found to be very similar in all clusters that have been inspected. Aims . We aim to characterize the low-mass (sub)stellar population of the central portion (2.4 pc2) of the ∼2 Myr old cluster NGC 2244 using near-infrared spectroscopy. By studying this cluster, characterized by a low stellar density and numerous OB stars, we aim to explore the effect that OB stars may have on the production of BDs. Methods . We obtained near-infrared HK spectroscopy of 85 faint candidate members of NGC 2244. We derived the spectral type and extinction by comparison with spectral templates. We evaluated cluster membership using three gravity-sensitive spectral indices based on the shape of the H-band. Furthermore, we evaluated the infrared excess from Spitzer of all the candidate members of the cluster. Finally, we estimated the mass of all the candidate members of the cluster and derived the initial mass function, star-to-BD number ratio, and disk fraction. Results . The initial mass function is well represented by a power law (dN/dM ∝ M−α) below 0.4 M⊙, with a slope α = 0.7–1.1 depending on the fitted mass range. We calculated a star-to-BD number ratio of 2.2–2.8. We find the low-mass population of NGC 2244 to be consistent with nearby star-forming regions, although it is at the high end of BD production. We find BDs in NGC 2244 to be, on average, closer to OB stars than to low-mass stars, which could potentially be the first piece of evidence that OB stars affect the formation of BDs. We find a disk fraction of all the members with a spectral type later than K0 of 39 ± 9% which is lower than typical values found in nearby star-forming regions of similar ages.Peer reviewe
The pulse of dialogue : explaining opposition to energy policies in Western Macedonia and Crete
Full text linkGuided by two core questions, this dissertation undertakes an exploratory journey into the dialogical dynamics of knowledge production. The first question analyses the explanatory strength of what I describe as “dialogical ethnographic theory,” theoretical frameworks formed in partnership with members of energy initiatives. This learning objective revolves around the explanatory potential of dialogical ethnographic theory vis-à-vis more hegemonic theoretical approaches that could have been employed, particularly the Theory of Planned Behaviour, a widely used model for interpreting psychosocial phenomena in social and environmental psychology. The second question explores the complications and implications of taking up dialogical approaches in the empirical social sciences.
The dissertation is structured into three main parts. In Part I, I draw on critical realism to explore the role of metatheory as an underlabourer, that is, as a supportive foundation for the explanatory-emancipatory social sciences. Part I explores the ontological, epistemological, methodological, and axiological implications of dialogical and explanatory approaches. Part II offers an in-depth analysis of the ethnographic fieldwork with energy initiatives against industrial renewable energy resources in Western Macedonia and the hydrocarbon exploration in Crete. Part II explores how explanatory ethnographic theories may be co-shaped through dialogues with members of community-based energy initiatives. Part III examines the dissertation’s contribution to critical theorisation in energy research. Drawing upon critical realism and dialogical ethnographic theory, Part III addresses the first research question by undertaking a metacritique of theorisation within the empirical social sciences, with particular emphasis on psychological theory. The second question is addressed through a reflective inquiry into both the transformative potential and the challenges of dialogical approaches amid the climate emergency."The opportunity to pursue my studies and writing throughout my third year was made possible through a scholarship at the Center for Environmental Studies, Rice University, funded by the IKY Greek State Scholarships Foundation in collaboration with Fulbright Greece. In my fourth year, I undertook an Erasmus internship at the Critical Realism– Interdisciplinarity, Sustainability, Education, and Social Science (CRISES) Center at the University of Applied Science in Lillehammer, Norway, under the mentorship of Leigh Price. My research at CRISES subsequently obtained financial support via the Roy Bhaskar Memorial Fund."--Fundin
Indian Ocean humpback dolphin (Sousa plumbea) surveys in the Tanga-Shimoni seascape of Tanzania and Kenya : final report
Full text linkThe Indian Ocean humpback dolphin is a poorly known but highly threatened coastal dolphin that was first recognized as a distinct species in 2014 (Jefferson and Rosenbaum 2014). Recent findings across Africa indicate alarming declines in Indian Ocean humpback dolphin populations, reflected in reduced abundance, group size, and sighting rates. The goal of this project was to increase understanding of the ecology and habitats of Indian Ocean humpback dolphins in the Tanga-Shimoni seascape in order to guide future conservation and management actions. These efforts were explicitly designed to assess transboundary movements—an essential aspect of understanding the spatial ecology, population structure, and movement dynamics of the species—and how these may be affected by increasing threats such as such as the development of the EACOP jetty at Tanga, increased vessel traffic, fisheries, tourism, and coastal development, may affect the species. The survey area covers 1,134km2, of which 814 km2 (72%) lies within Tanzania and 320 km2 (28%) within Kenya. It was defined to encompass waters 25m depth or less, stretching from the Pangani river in the Tanga region of northern Tanzania to the northern boundary of the Kisite-Mpunguti Marine Park in Shimoni, Kenya. Four boat-based cetacean surveys were conducted across the study site over two years (2023 and 2024) within two seasons (April-May, and October-November). The total on-effort survey distance from all four surveys and two countries combined was 3,870 km. A total of 59 groups of cetaceans were recorded during the surveys which included 33 of Indo-pacific bottlenose dolphin (Tursiops aduncus) groups and 23 of Indian Ocean humpback dolphin (Sousa plumbea) groups. Indian Ocean humpback dolphins generally occurred in small groups of between 1 and 18 (mean group size=6.3, SD=5.1). Group size documented in Tanzania was slightly larger (mean=6.6, SD=5.3) than group size seen in Kenya (mean=4.8, SD=3.8). The number of groups of humpback dolphins per kilometre of survey effort (sighting rate), was more than twice as high in Tanzania (0.007/km), than in Kenya (0.003/km). The sighting rate for humpback dolphins was identical in each season (0.006/km) with animals seen in both survey seasons. Humpback dolphins occurred in water between 4.5 and 18m in depth, but the majority of sightings were in very shallow water with a median depth at sighting locations of 5.4m (SD=4.4). A total of 1,147 images of 20 humpback dolphin groups were of sufficient quality for use in the creation of a photo-ID catalogue. Twenty-four unique humpback dolphin individuals were identified in the current catalogue. Closed population mark-recapture models with full individual heterogeneity were used to estimate the abundance of marked animals across the study site. The final estimate of abundance for marked individuals (Nm) was 40 (SE=13.7, 95%CI: 28-93). The proportion of the population that carry permanent marks was 0.68 (SE= 0.08), suggesting that an estimated 19 (SE=9.6) of animals in the population were unmarked (Nu). The overall abundance estimate for marked and unmarked humpback dolphins present in the study area was 59 (SE=21.45, CV=0.37, 95% CI:29-117). Three individuals, all females were seen 9, 8 and 7 times respectively, all at locations in both Tanzania and Kenya. The greatest distance between sighting locations was 84km recorded for two dolphins sighted near Kigombe, Tanzania, and later in Shimoni, Kenya. The clear distribution hotspot for humpback dolphins in the survey region was within Mwarongo Bay where there were three times more sightings than all other survey locations. Species distribution models were developed using generalized additive models (GAMs), with humpback dolphin presence-absence as the response variable and twelve environmental parameters as explanatory variables. GAM results with the lowest AIC showed the most important predictor variables for humpback dolphin presence to be chlorophyll (CHL), potential bottom temperature (PTMPb), absolute surface salinity (ASAL1), and tide. Dolphin presence was highest in areas of high chlorophyll content, within water temperatures of 28 to 30oc, not influenced by freshwater input and outside of spring tide periods. Acoustic data of the vocal repertoire of humpback dolphin and Indo-pacific bottlenose dolphins were collected during the visual surveys. The acoustic data from all encounters of humpback dolphins were summarised descriptively and statistical comparisons between the two species were made using the data from single species encounters (i.e. without incorporation of the ‘probable’ data class). Significant differences between the two species across all parameters could be found (non-parametric ANOVA, Wilcoxon test p< 0.01, humpback dolphin n = 1360, bottlenose dolphin n = 1167). Overall, both the collected focal follow acoustic data and comparisons with published literature, demonstrates clear and stable differences between the whistle characteristics of the two species and clear similarities within the species over time and within regions. These detailed observations enabled confident species classification by an experienced acoustic analyst familiar with the acoustic repertoire of dolphins in the study region. Passive acoustic monitoring at three sites (Wasini Channel, Fish Eagle Point and Mwarongo) was conducted over a year and there were 162 acoustic detections of dolphins the vast majority of which (147 or 90%) could be assigned as humpback dolphin or mixed species groups. The Mwarongo site had high detection rates for humpback dolphins, with dolphins encountered on 31% of monitoring days. This study provides a comprehensive baseline of information from which to move forward with integrating marine mammal conservation into marine park management plans and providing an evidence base for cross-boundary collaboration on marine resource management
Similarities and differences between non-linear force-free fields produced by evolution and extrapolation techniques
Full text linkFunding: DHM would like to thank the UK STFC for financial support under grant numbers ST/W001195/1 and SMC1-XAS012.Non-Linear Force-Free Fields (NLFFF) play a key role in our understanding of the nature and evolution of coronal magnetic fields. Two of the most common methods for their construction are the “extrapolation” and “evolution” approaches. The aim of the present paper is to compare results from these two approaches when they have the same vector magnetic field on the bottom boundary. To begin with a NLFFF evolution simulation of AR10977 is carried out to produce a time series of the vector field at the lower boundary covering the full life-span of the active region. Next at eight unique times in this time series, NLFFF extrapolations are constructed using the simulated vector boundary data. The resulting 3D coronal magnetic fields are then compared. During the early stages in the lifetime of AR10977, when the coronal magnetic field is composed of simply connected field lines, both NLFFF approaches produce a high level of agreement as long as the full vector field is injected into the extrapolation. When injection is limited to only strong field locations, a poorer agreement is found. In contrast, once a flux rope has formed during the later stages in the lifetime of the active region poor agreement is found between the two approaches, regardless of how the boundary information is injected in the extrapolations. This indicates that once a flux rope has formed through flux cancellation and risen into the corona the information held within the boundary vector field is insufficient to capture the complexity of the 3D coronal magnetic field. This result is also supported by the poor agreement that arises when comparing the relative magnetic helicity between the two modelling approaches. While the present study considers one extrapolation approach, it is important to repeat the study using alternative extrapolation methods that exist in the published literature.Peer reviewe
Laboratory experiments in geophysical and astrophysical fluid dynamics
Full text linkFunding: M.L.B. acknowledges funding from the Programme National de Planétologie of CNRS-INSU cofunded by CNES, from the French Agence Nationale de la Recherche, from the European Research Council, and from the Simons Foundation, all of which have supported the development of experimental setups at various scales over time. D.L. acknowledges support from the Royal Society via grant RG/R1/241426 and from UK Research and Innovation via a Future Leaders Fellowship (grant MR/Y01605X/1).Geophysical and astrophysical fluid dynamics (GAFD) is an interdisciplinary field. It encompasses a wide range of fluid systems, from planetary atmospheres and the oceans of Earth and icy moons to the interiors of telluric planets, giant planets, and stars. It also spans vast timescales and space scales. Despite this diversity, GAFD is built on common challenges in fundamental fluid mechanics, requiring a multi-approach strategy that integrates theory, simulations, and experiments to explain observations. This review highlights the role of laboratory experiments in GAFD. We first emphasize recent advances in experimental design, methods, and metrology, including large-scale facilities as well as innovative and analog setups. We then focus on two areas where experiments have driven recent breakthroughs: rotating turbulence and flows involving multiphase and phase-change processes. Finally, we discuss emerging challenges and the potential of outreach experiments to stimulate interest in fluid mechanics among students and the public.Peer reviewe
Christian consolation and theology's task today
Full text linkFramed by Isaiah 41, this article proposes a theology of consolation which does not seek to dismiss or minimize the reality of suffering. Instead, the centrality of the cross in Christian theology dignifies human experiences of suffering, frailty and even mortality, such as those that face us in a time of COVID-19. And yet, because the crucifixion births resurrection, Christian consolation can offer more than dignity and understanding, it also offers real hope and meaning in and through suffering.Peer reviewe
Automated detection of shoulder arthroplasty in X-rays using machine learning
Full text linkDemand for shoulder arthroplasty is rising at a faster rate than hip and knee arthroplasty, driven by an increasingly aging yet active population. Joint registries are playing an increasingly critical role in tracking the long-term success of shoulder arthroplasty, identifying failure mechanisms, and shaping clinical best practices but current classification procedures are often performed by non-medically trained encoders leading to error. This study examines the use of machine learning in techniques to classify four broad categories of shoulder arthroplasty technique from postoperative x-rays. Data from the Scottish Arthroplasty Project, was used to create a balanced dataset of 1000 samples. A 10-fold cross validation was used for the training of 4 neural network models commonly used for classification of x-ray data. InceptionV3 model achieved the highest overall performance with an accuracy of 93.85% after cross validation, while EfficientNet demonstrated the highest individual classifier accuracy of 99% suggesting the potential to increase accuracy further in future studies.Clinical Relevance- This research highlights the potential of machine learning to enhance the accuracy of joint registry data encoding. Facilitating evidence-based improvements in implant design and surgical approaches through the use of more accurate data on implant survival, and revision rates
Carbonate-associated phosphate evidence for a small inorganic phosphorus reservoir in the terminal Ediacaran ocean
Full text linkFunding: This research is financially supported by NSFC, and the Key R&D Project of the Ministry of Science and Technology (42130208, 2022YFF0800100, 42425002, 42572399, 42002027).The terminal Ediacaran (ca. 551–533 Ma) was characterized by profound biological innovations and environmental upheavals, in which phosphorus (P)—the ultimate limiting nutrient for marine productivity—is postulated to have played a key role. However, P availability in the terminal Ediacaran ocean remains uncertain due to the lack of an appropriate proxy record. To better reconstruct seawater P levels during this time interval, we analyzed carbonate-associated phosphate [CAP; expressed as CAP/(Ca + Mg)], a new proxy for P availability in ancient oceans, in three upper Ediacaran successions: the Nama Group (Namibia), the Shibantan Member of the Dengying Formation (Wuhe, South China), and the Algal Dolomite, Gaojiashan and Beiwan members of the Dengying Formation (Gaojiashan, South China). Our results reveal consistently low CAP/(Ca + Mg) values (range: 0.02–0.69 mmol/mol, mean: 0.13 ± 0.01 mmol/mol, 2σ, the same below) for all study sections, falling at the lower end of modern marine carbonate values. Lithofacies, carbonate oxygen isotopes, Mn/Sr and Mg/(Mg + Ca) ratios indicate possible influences from release of Fe-bound P, meteoric diagenesis, recrystallization or dolomitization. The low CAP/(Ca + Mg) values thus represent a maximum estimate for the seawater P availability. The low CAP values from two geographically separated cratons likely reflect a generally small oceanic inorganic P reservoir at least in shelves. This study provides insights into the interplay between nutrient cycling, redox dynamics, and biological evolution during one of the most pivotal transitional periods in Earth history.Peer reviewe
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