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Inversion formula, unique continuation property, and range characterization of the mixed ray transform in R2
No full textIn this article, we study various aspects of the mixed ray transform of (k+ℓ)-tensor fields that are symmetric in its first k and last ℓ indices. As a first result, we derive an inversion algorithm to recover the solenoidal part of the unknown tensor field using the normal operator of the mixed ray transform. Next, we establish a set of unique continuation results. In addition to these, we discuss the range characterization of the mixed ray transform as the final result
Partially Substituted La for Sm in Sm0.8Sr0.2NiO3: An Efficient Electrocatalyst Towards Alkaline Water Splitting
No full textPerovskite-type oxides having composition LaxSm0.8−xSr0.2NiO3 (0 ≤ x ≤ 0.6) were explored for their ability to act as facilitators for oxygen evolution reaction (OER) in alkaline media. Synthesis of the materials was conducted through a sol-gel procedure via malic acid. The materials underwent advanced physicochemical characterization utilizing techniques, namely transmission electron microscope (TEM), scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS), inductively coupled plasma – mass spectrometry (ICP-MS) and X-ray diffraction (XRD). These analyses provided crucial details about the material’s particle size, surface morphology/chemical composition and crystalline structure, opening up exciting possibilities for their diverse applications. From TEM analysis, the average particle size of the oxide materials has been estimated and found to be 5.9 nm for Sm0.8Sr0.2NiO3 and 4.8 nm for La0.6Sm0.2Sr0.2NiO3. The particle size of the oxide material decreases when La was partially substituted for Sm in Sm0.8Sr0.2NiO3. Cyclic voltammetry and Tafel plot were observed for the electrochemical analysis in 1 M KOH (25 °C). An investigation on the anodic polarization of oxides revealed an increased electrocatalytic activity when La was partially substituted for Sm in Sm0.8Sr0.2NiO3. La0.6Sm0.2Sr0.2NiO3 was found to be most active at 800 mV with a current density, j = 184.1 mA/cm2. The Tafel experiment was conducted in 1M KOH at varying temperatures to determine thermodynamic properties like standard electrochemical energy of activation ((Formula presented.)), standard enthalpy of activation (ΔH°#), and standard entropy of activation (ΔS°#)
High Ionic Conduction and Polarity-Induced Piezoresponse in Layered Bimetallic Rb4Ag2BiBr9 Single Crystals
No full textThe emergence of lead-free metal-halide perovskites in modern-day energy research is primarily due to their competent semiconducting and optoelectronic properties, as well as their nontoxicity and improved stability in ambient operating conditions. However, a detailed understanding of ion transport dynamics and the relaxation behavior of these materials is still elusive. In this article, we report on the single-crystal (SC) growth of a bimetallic two-dimensional layered Rb4Ag2BiBr9 and explore its dielectric, piezoelectric, and ferroelectric properties. The dielectric attributes are investigated by studying the temperature-dependent complex impedance, complex electric modulus, and AC conductivity over an extensive frequency range from 4 Hz to 8 MHz. The role of grain and grain boundaries in the effective impedance is established using the Maxwell-Wagner equivalent circuit model from the Nyquist plots. The observed electric modulus spectra are studied using the Havriliak-Nigami and the Kohlrausch-Williams-Watts formalisms to understand the ionic transport and relaxation mechanisms in Rb4Ag2BiBr9. The DC conductivity and relaxation time show Arrhenius-like behavior with the inverse temperature validating the hopping motion of ions. The values of the activation energy required for ion hopping are calculated independently from the relaxation time, hopping frequency, and DC conductivity Arrhenius plots and are in good agreement with a value of 0.47 eV. The scaling of the temperature-dependent conductivity and electric modulus spectra into a single master curve demonstrates the congruence of the ionic conduction and the relaxation phenomena at different temperatures for Rb4Ag2BiBr9. This SC demonstrates decent thermal and ambient stability up to 500 �C and 12 months, respectively. The pristine orthorhombic Rb4Ag2BiBr9 SC shows a piezoelectric amplitude value of ?564 pm at the maximum applied bias (�10 V), and a saturation polarization of ?0.14 nC/cm2 estimated from the piezoelectric force microscopy and polarization hysteresis loop measurement, respectively. The ferroelectric and semiconducting attributes of this material can be harnessed for prospective applications as a thin film in designing mechanical energy harvesters as well as functional photoferroelectrics, such as optical switches and ferroelectric photovoltaics. � 2023 Elsevier B.V., All rights reserved
Investigating non-local contributions in Bs→ϕℓ¯ℓ including higher-twist effects
No full textWe analyze the impact of higher-twist three-particle Bs-meson light-cone distribution amplitudes (LCDAs) on the non-local form factors for the Bs→ϕℓ¯ℓ transition focusing on the ‘charm-loop’ contribution within the light-cone sum rule (LCSR) framework. To analytically continue these charm-loop contributions into the kinematically allowed region of the decay, we employ a hadronic dispersion relation that incorporates intermediate resonant states such as the ϕ, J/Ψ and ψ(2S) mesons. Here, the LCSR predictions serve as inputs, supplemented by experimental data from two-body decays Bs → ϕ + resonance states. Our results indicate that the inclusion of twist-5 and twist-6 LCDAs enhances the non-local form factors — by approximately an order of magnitude — compared to previous estimates, due to partial disruption of cancellation among different twist contributions. This leads to a dilepton invariant mass-squared (q2)-dependent correction to the Wilson coefficient C9, which is higher than, but still consistent with the Standard Model prediction without the non-factorizable charm-loop corrections within uncertainties. Additionally, we update the local form factors to include contributions from higher-twist three-particle Bs-meson LCDAs. The phenomenological implications, particularly for the differential branching fraction and angular observables, are also discussed
Smoothed particle hydrodynamics (SPH) investigation of two-dimensional dam break flows
No full textThe study of dam break flow (DBF) is essential as it is associated with losses to lives and properties. In this study, 2-D DBF is numerically investigated using a mesh-free Lagrangian approach, i.e., the smoothed particle hydrodynamics (SPH) technique by writing a code. The concept of cylindrical columns of water particles and the variable smoothing length technique is adopted to estimate the shock waves in the channel and floodplains. The evolution of the flow field in terms of flow depth and velocity in channel transitions is obtained. The model performance is evaluated by comparing the simulated results with analytical and experimental data in the literature. Several numerical examples considered in the study accurately model the mixed regimes of flow with moving fronts without any special numerical treatment
Multimodal Interactions and Explainable AI for Reflective Physical and Online Learning: MiXai^learn Workshop
No full textThis half-day workshop discusses application of explainable AI and multimodal interactions with personal devices, tangible electronics and social robots for fostering reflective learning practices in physical and online learning scenarios. Reflective practices in education have been shown to improve student achievement and prepare students for a sustainable society. Still, learning activities that are across physical and online learning spaces make it difficult to assess reflection skills and support them comprehensively. Recent advances in robotics, sensors, machine learning and generative AI provide opportunities to create technologies to capture and analyze data in a hybrid format across physical and online spaces. The workshop aims to bring together experts from the fields of AI, learning analytics, sensing technologies, and learning sciences to discuss technologies for detecting, understanding, and predicting learning distributed in physical and online spaces, as well as to discuss what is pedagogically desirable, technically feasible, and ethically sound. As a technology context we will demonstrate the functionalities of the LA-ReflecT platform, which is being developed and used as part of this international collaboration. This workshop is important to the AIED community, particularly those developing technologies to capture learning in hybrid spaces or, more generally, complex multimodal student interactions
Petrogenesis of the Rantila meteorite fall and implications for the origin of aubrites
No full textAubrites are rare meteorites from highly reduced differentiated parent bodies. The Rantila meteorite was recovered soon after falling on 17 August 2022 at Rantila and Ravel villages in Gujarat state, India. We report the petrography, mineralogy, chemical composition, oxygen- and chromium-isotope compositions, along with reflectance spectroscopy, all showing that Rantila is an aubrite. Coarse enstatite and diopside grains constitute the main mass of Rantila, while mm-wide fracture domains pervade the coarse enstatites. In the fractures, comminuted enstatite, diopside blebs, olivine, a plagioclase–silica assemblage, sulfides, and metals occur. Rantila consists of enstatite (>85 vol%), diopside (~8 vol%), forsterite, albite, and silica along with various sulfides and Fe-Ni alloys. The concentration of rare earth elements is ~1–2 × CI, consistent with main group aubrites. Noble gas and nitrogen isotopic analyses reveal young exposure ages (13.81 ± 6.47 Ma), a heterogeneous nitrogen isotopic composition, and a major K-Ar resetting event around 3.2 ± 0.4 Ga in the parent body of Rantila. The bulk oxygen isotope values are within the range of aubrites. The chromium isotopic values of Rantila are consistent with main group aubrites. The mineral assemblages, texture, and crystallization modeling suggest that Rantila had an igneous origin. The mineral assemblages in fractures indicate the involvement of external melt possibly during an impact-fracturing event, which aligns well with the heterogeneous N isotopic composition. Additionally, Rantila shows a wider range of oxygen isotopes than other aubrites suggesting some extent of O isotopic heterogeneity, likely stemming from exogenous processes. The variation in intra-sample bulk O and N isotope values implies inherent heterogeneity within the main group aubrites, potentially caused by late-stage impact contamination
Reducing the uncertainty in the distribution of cm-scale rock properties in the near well-bore region
No full textRock properties at cm-scale impact geological carbon storage by enhancing capillary and mineral trapping. Hence, it is important to accurately capture their distribution in geo-models which are used for numerically estimating the fate of injected CO2. However, there could be high variability in the cm-scale distribution of rock properties even close to wells which is not captured with traditional workflows. This study explores the impact of grid cell resolution, seismic inversion and placement of an additional well in proximity to CO2 injection well on improving the representation of cm-scale lithological heterogeneity in the near well bore region in geological models. We utilize wireline and seismic data from Parasequence-2 of the Paaratte Formation, Otway Basin, Australia, which is a shallow to coastal marine deltaic deposition comprising a high degree of lithological heterogeneity and a prospective unit for pilot scale geological carbon storage operations. The data was used to prepare a suite of reservoir models capturing the impact of above factors on the plausible distributions of facies, porosity and permeability in the formation. The analysis suggests that smaller grid cell size (1 m x 1 m x 0.3 m) compared to the typical industry standard (10 m x 10 m x 2 m) significantly improves the representation of cm-scale rock properties. Additionally, stochastic seismic inversion could play an important role in capturing rock property distribution even for smaller CO2 storage sites used for pilot scale injection operations. Further, we show that the placement of an additional well only 116-m away from the CO2 injection well can drastically improve the probability in the distribution of cm-scale rock properties in reservoir models
An Old Language for a New World: Assessing the Epical Shift in the Popular Cultural Discourse
No full textThe post-war period in Europe was a period of contradictions; on one hand, there was disenchantment with greater visions of life and history; while on the other hand, there was a revival of the enchanting mythical worlds in literature and popular culture. The postmodern condition as described by Lyotard was twilight of grand narratives and at the same time it opened up possibilities of a newer narrative to assert itself. The dissolution of the modernist self as well as the construction of a new self that was master of the language games played in an information society happened at the same time. The aim of this article is to look into the fields of popular culture and emerging management discourse that is relying on mythology, narratives and storytelling, to figure out how they are reinventing a lost bardic tradition by using language as an indispensable tool in shaping up individuals and societies. This article argues that in the postmodern age, a new idea of �self� has simultaneously taken shape whose template overlaps with the �epical self�, relying on language as an important mode of transformation. This article makes a case for deeper and nuanced understanding of popular cultural elements and usage of language in management literature. � 2025 Elsevier B.V., All rights reserved