Addressing degradation of Ni/YSZ cermet fuel electrode in reversible solid oxide cells

Funding: This work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) under the project “High efficiency reversible solid oxide cells for the integration of offshore renewable energy using hydrogen – expertise and track record of the team” (Grant Number: EP/W003686/1). The research group at the Institute of Power Engineering – National Research Institute acknowledges the IPE-NRI statutory grant, “Development of Reversible Solid Oxide Cells (SOC) Based on the Institute of Power Engineering's Technology for Power-to-X Systems”, for the project running from 2022 to 2024). EPSRC grants EP/T019298/1 and EP/R023751/1 are also acknowledged.Ni cermet fuel electrodes yield excellent electrochemical performance in solid oxide cells (SOCs), but their long-term stability is hindered by degradation mechanisms related to Ni agglomeration. While microstructure engineering can slow this degradation, it remains an intrinsic issue. Here, a new approach is presented to mitigate this degradation through infiltration of cerium oxides. This study shows that adding nanostructured CGO reduces degradation and enhances stability in the reversible mode. Although some agglomerations is observed, it does not impact cell performance. CGO-infiltrated cells exhibited no signs of degradation over 650-hours in reversible mode at 750°C, alternating between high hydrogen concentration (97% H2 and 3% H2O) at 0.8 V and high steam concentration (10% H2 and 90% H2O) at 1.27 V. Generated current increased in FC mode (from 0.20 to 0.31 Acm−2) and from 0.39 to 0.65 Acm−2 in EC mode. In contrast, non-infiltrated cells showed a decline in EC mode from 0.67 to 0.2 A cm−2 and in FC mode from 0.49 to 0.31 Acm−2 after 400h. This offers a promising route to improving SOCs. Ni agglomeration's minor effect on electrochemical activity suggests the reaction has moved from the triple-phase boundary at the electrode gas interface to the double-phase boundary.Peer reviewe

A minimal model to diagnose the contribution of the stratosphere to tropospheric forecast skill

Funding: Simon H. Lee is supported by NERC via the SCENARIO Doctoral Training Partnership (NE/L002566/1). Isla R Simpson was supported by the National Center for Atmospheric Research, which is a major facility sponsored by the National Science Foundation under the Cooperative Agreement 1852977.Many recent studies have confirmed that variability in the stratosphere is a significant source of surface sub-seasonal prediction skill during Northern Hemisphere winter. It may be beneficial, therefore, to think about times in which there might be windows-of-opportunity for skillful sub-seasonal predictions based on the initial or predicted state of the stratosphere. In this study, we propose a simple, minimal model that can be used to understand the impact of the stratosphere on tropospheric predictability. Our model purposefully excludes state dependent predictability in either the stratosphere or troposphere or in the coupling between the two. Model parameters are set up to broadly represent current sub-seasonal prediction systems by comparison with four dynamical models from the Sub-Seasonal to Seasonal Prediction Project database. The model can reproduce the increases in correlation skill in sub-sets of forecasts for weak and strong lower stratospheric polar vortex states over neutral states despite the lack of dependence of coupling or predictability on the stratospheric state. We demonstrate why different forecast skill diagnostics can give a very different impression of the relative skill in the three sub-sets. Forecasts with large stratospheric signals and low amounts of noise are demonstrated to also be windows-of-opportunity for skillful tropospheric forecasts, but we show that these windows can be obscured by the presence of unrelated tropospheric signals.Peer reviewe

The tidal deformation and atmosphere of WASP-12b from its phase curve

Funding: LCa and CHe acknowledge support from the European Union H2020-MSCA-ITN-2019 under Grant Agreement no. 860470 (CHAMELEON). ACCa and TWi acknowledge support from STFC consolidated grant numbers ST/R000824/1 and ST/V000861/1, and UKSA grant number ST/R003203/1. PM acknowledges support from STFC research grant number ST/M001040/1. NAW acknowledges UKSA grant ST/R004838/1.Context. Ultra-hot Jupiters present a unique opportunity to understand the physics and chemistry of planets, their atmospheres, and interiors at extreme conditions. WASP-12 b stands out as an archetype of this class of exoplanets, with a close-in orbit around its star that results in intense stellar irradiation and tidal effects. Aims. The goals are to measure the planet’s tidal deformation, atmospheric properties, and also to refine its orbital decay rate. Methods. We performed comprehensive analyses of the transits, occultations, and phase curves of WASP-12b by combining new CHEOPS observations with previous TESS and Spitzer data. The planet was modeled as a triaxial ellipsoid parameterized by the second-order fluid Love number of the planet, h2, which quantifies its radial deformation and provides insight into the interior structure. Results. We measured the tidal deformation of WASP-12b and estimated a Love number of h2 = 1.55−0.49+0.45 (at 3.2σ) from its phase curve. We measured occultation depths of 333 ± 24 ppm and 493 ± 29 ppm in the CHEOPS and TESS bands, respectively, while the nightside fluxes are consistent with zero, and also marginal eastward phase offsets. Our modeling of the dayside emission spectrum indicates that CHEOPS and TESS probe similar pressure levels in the atmosphere at a temperature of ~2900 K. We also estimated low geometric albedos of Ag = 0.086 ± 0.017 and Ag = 0.01 ± 0.023 in the CHEOPS and TESS passbands, respectively, suggesting the absence of reflective clouds in the high-temperature dayside of the planet. The CHEOPS occultations do not show strong evidence for variability in the dayside atmosphere of the planet at the median occultation depth precision of 120 ppm attained. Finally, combining the new CHEOPS timings with previous measurements refines the precision of the orbital decay rate by 12% to a value of −30.23 ± 0.82 ms yr−1, resulting in a modified stellar tidal quality factor of Q′★ = 1.70 ± 0.14 × 105. Conclusions. WASP-12 b becomes the second exoplanet, after WASP-103b, for which the Love number has been measured from the effect of tidal deformation in the light curve. However, constraining the core mass fraction of the planet requires measuring h2 with a higher precision. This can be achieved with high signal-to-noise observations with JWST since the phase curve amplitude, and consequently the induced tidal deformation effect, is higher in the infrared.Peer reviewe

Impurity band formation as a route to thermoelectric power factor enhancement in n-type XNiSn half-Heuslers

Funding: The EPSRC is acknowledged for support under award EP/N01717X/1, EP/N01703X/1, EP/X02346X/1, EP/L017008/1, EP/R023751/1 and EP/T019298/1 and for a PhD studentship for S.A.B.Bandstructure engineering is a key route for thermoelectric performance enhancement. Here, 20–50% Seebeck (S) enhancement is reported for XNiCuySn half-Heusler samples based on X = Ti. This novel electronic effect is attributed to the emergence of impurity bands of finite extent, due to the Cu dopants. Depending on the dispersion, extent, and offset with respect to the parent material, these bands are shown to enhance S to different degrees. Experimentally, this effect is controllable by the Ti content of the samples, with the addition of Zr/Hf gradually removing the enhancement. At the same time, the mobility remains largely intact, enabling power factors ≥3 mW m−1 K−2 near room temperature, increasing to ≥5 mW m−1 K−2 at high temperature. Combined with reduced thermal conductivity due to the Cu interstitials, this enables high average zT = 0.67–0.72 between 320 and 793 K for XNiCuySn compositions with ≥70% Ti. This work reveals the existence of a new route for electronic performance enhancement in n-type XNiSn materials that are normally limited by their single carrier pocket. In principle, impurity bands can be applied to other materials and provide a new direction for further development.Peer reviewe

Modality, truth and mere picture thinking

Many draw the distinction between truth in, and truth at, a possible world. The latter notion purportedly allows for propositions to be true relative to worlds even if they do not exist relative to those same worlds. Despite its wide application, the distinction is controversial. Some think that the notion of truth at a world is unintelligible. Here, I outline and discuss the most influential argument for the unintelligibility of truth at a world, The Picture Thinking Argument. I outline and defend a neglected strategy to respond to this, arguing that if we take seriously the idea that possible worlds represent total ways the world could be, the distinction can be drawn intelligibly.Peer reviewe

The messy art of conversation in practical theology : explorations and reflections

Using autoethnography, the authors (a Muslim woman and a Christian man) reflect on their co-creation of a podcast series, ‘Conversations in Practical Theology’, which they commenced in 2017. Locating the precipitating factors in their experiences of the British and Irish Association for Practical Theology (BIAPT) conference that year, and their respective faith contexts of Islam and Christianity, they test Stephen Pattison’s 2020 proposal that practical theology is fundamentally a practice of conversation. They argue that through encountering one another (and themselves) in podcasting, it is the eclecticism and haphazardness of their intellectual engagement, crucially as representatives of no-one but themselves, that Pattison’s contention of the messiness of good practical theological conversation is upheld.Peer reviewe

Knowledge, inquiry and dogmatism

The popular idea that knowledge is the aim of inquiry appears to licence a specific form of dogmatism: once one knows the answer to a question, one ought to decline further evidence bearing on it. For, in knowing the answer to the question, one has already met the aim of inquiry. And by gathering further evidence one risks losing that knowledge by acquiring misleading evidence. After distinguishing the relevant form of dogmatism from standard dogmatism, I reject a range of different responses to this challenge including that gathering further evidence may answer alternative inquiries, the idea that the aim of inquiry is not knowledge but something stronger, or appeal to the personal aims of inquirers. Here I argue that none of these replies are adequate and instead suggest a solution that appeals to situation-sensitive epistemic norms on inquiry.Peer reviewe

Kinetic and thermodynamic characterization of human 4-oxo-L-proline reductase catalysis

Funding: This work was supported by a Cunningham Trust Ph.D. Award (Grant PhD-CT-21-04) to R.G.d.S., which supports a Ph.D. studentship to E.P.The enzyme 4-oxo-l-proline reductase (BDH2) has recently been identified in humans. BDH2, previously thought to be a cytosolic (R)-3-hydroxybutyrate dehydrogenase, actually catalyzes the NADH-dependent reduction of 4-oxo-L-proline to cis-4-hydroxy-L-proline, a compound with known anticancer activity. Here we provide an initial mechanistic characterization of the BDH2-catalyzed reaction. Haldane relationships show the reaction equilibrium strongly favors the formation of cis-4-hydroxy-L-proline. Stereospecific deuteration of NADH C4 coupled with mass spectrometry analysis of the reaction established that the pro-S hydrogen is transferred. NADH is co-purified with the enzyme, and a binding kinetics competition assays with NAD+ defined dissociation rate constants for NADH of 0.13 s–1 at 5 °C and 7.2 s–1 at 25 °C. Isothermal titration calorimetry at 25 °C defined equilibrium dissociation constants of 0.48 and 29 μM for the BDH2:NADH and BDH2:NAD+ complexes, respectively. Differential scanning fluorimetry showed BDH2 is highly thermostabilized by NADH and NAD+. The kcat/KM pH–rate profile indicates that a group with a pKa of 7.3 and possibly another with a pKa of 8.7 must be deprotonated and protonated, respectively, for maximum binding of 4-oxo-L-proline and/or catalysis, while the kcat profile is largely insensitive to pH in the pH range used. The single-turnover rate constant is only 2-fold higher than kcat. This agrees with a pre-steady-state burst of substrate consumption, suggesting that a step after chemistry, possibly product release, contributes to limit kcat. A modest solvent viscosity effect on kcat indicates that this step is only partially diffusional. Taken together, these data suggest chemistry does not limit the reaction rate but may contribute to it.Peer reviewe

Utilizing virtual reality to assist social competence education and social support for children from under-represented backgrounds

Funding: This publication has emanated from research conducted with the financial support of Trinity College Dublin-China Scholarship Council Joint Scholarship (ID 202008300006) and Horizon Europe Framework Program (HORIZON - ID 6101070109).Although education is a fundamental human right for global citizens, educational inequality still exists within and among countries. Still today, many students struggle to access and receive quality education. Therefore, the value of using immersive technology to increase social competence and perceived social support for children who live in remote areas of the world, reduce inequality, and improve the quality of education requires much attention to address the lacuna between urban and rural education systems. Based on three representative pedagogies (Pedagogy of Technology, Play-based Learning, and Traditional Pedagogy), we designed three social competence educational approaches – virtual reality (VR) assisted social competence education, Lego social competence education, and traditional classroom learning – and applied them to interventions in two rural schools in Southwest China. Our results showed that VR and Lego social competence education prompted children's social competence and perceived social support with elementary school children (Study 1). Furthermore, VR social competence education resulted in substantially greater social competencies and subjective sense of social support than traditional classroom learning with middle school children (Study 2). The results suggest that VR-assisted social competence education (Pedagogy of Technology) could be a potential tool to reduce educational inequalities in underdeveloped countries and regions.Peer reviewe

Insights to the formation of Zr-based metal–organic frameworks from in situ powder x-ray diffraction

Funding: We gratefully acknowledge Dr Aamod V Desai for fruitful discussions. RE and EEP thank the Fonds der Chemischen Industrie for a Liebig Fellowship. This work was supported by the European Research Council grant ADOR (Advanced Grant 787073). The authors acknowledge the EPSRC Light Element Analysis Facility Grant (EP/T019298/1), the EPSRC Strategic Equipment Resource Grant (EP/R023751/1), the EPSRC Core Equipment Grant (EP/V034138/1) and EP/W034824/1. EALB acknowledges the Allan Handsel Postgraduate Research Scholarship for Chemistry for studentship funding.This study sheds light on the kinetics of crystallisation of two Zr-based metal–organic frameworks (MOFs), namely Zr6-MOF-808 and Zr6-MOF-801, using in situ powder x-ray diffraction (PXRD). Once a room temperature synthesis for the two MOFs was designed for the very small scale, a successful series of in situ PXRD experiments over the range of 10 °C–40 °C yielded high quality quantitative information on the kinetics of crystallisation for both MOFs. These findings indicate the importance of the solubility of the linker and its connectivity: while the rate of nucleation and the resulting particle size of the MOF (Zr6-MOF-801), with the less soluble and lower connected linker, was strongly temperature dependent, the growth and particle size of Zr6-MOF-808 was hardly impacted by an increase in temperature. This work highlights the importance of careful preliminary research and helps to improve future MOF synthesis design to efficiently achieve the desired particle size distribution.Peer reviewe