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Electrochemical performance of V2O5//f-CNT asymmetric flexible device for supercapacitor application
(Springer, 2025) Mishra, Ajay Kumar; Bulla, Mamta; Kumar, Vinay
The advancement of flexible supercapacitors has been constrained by the inherent difficulty of fabricating flexible electrodes. In this work, the V2O5 nanostructures were synthesized at different temperatures (120–200 °C) via hydrothermal treatment, followed by calcination, resulting in materials with high porosity and optimized electrochemical properties. The fabricated electrode (synthesized V2O5 at 180 °C) shows a maximum capacitance (178.5 F g⁻1 at 1 A g⁻1 current density) compared to other prepared samples 1 in a 1.0 M Na2SO4 aqueous electrolyte. For practical applications, V2O5 nanostructures were integrated with f-CNTs to fabricate the V2O5//f-CNT asymmetric supercapacitor device, achieving a specific capacitance of 104.4 F g⁻1 at 1 A g⁻1 within a 1.6 V voltage window, signifying improved charge storage capabilities. The device achieved an energy density of 37.12 Wh kg⁻1 and a power density of 800 W kg⁻1 at 1 A g⁻1. The synergistic integration of Faradaic reactions from V₂O₅ with the EDL capacitance of f-CNTs enabled the device to retain 91.2% of its capacitance after 2000 GCD cycles, with enhanced performance sustained up to 5000 cycles. Furthermore, the device demonstrated remarkable flexibility, losing only 4.3% of its capacitance when bent at a 90° angle, underscoring its potential as a high-performance energy storage solution. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.
A century later: discovery of a second Podospongia species offshore from the Table Mountain National Park MPA, South Africa
(Cambridge University Press, 2026) Samaai, Toufiek
A new sponge species (Demospongiae: Poecilosclerida: Podospongiidae) is described offshore from the Cape of Good Hope, on the southern edge of the Table Mountain National Park marine protected area. Podospongia capensis sp. nov. is compared to Podospongia natalensis, described by Kirkpatrick (1903) from the east coast of South Africa, as well as to all other Podospongia species described to date. The new species differs from P. natalensis in having a shorter, thicker stalk, lacking anisostrongyles as megascleres, and possessing a second category of large symmetrical aciculospinorhabds microcleres that are present in P. natalensis. Additionally, P. natalensis has larger oxeas and styles than those found in P. capensis sp. nov. Furthermore, the two species are geographically separated, with P. natalensis described from the Natal ecoregion, while P. capensis sp. nov. is described from the Southern Benguela ecoregion. The new species primarily differs from other congeners in external morphology and size of the oxeas and styles.
Luminescence and electroanalytical properties of carbon quantum dots in the context of immunosensor design
(John Wiley and Sons Inc, 2025) Louw, Clementine Juliat; Baker, Priscilla G L; Alemu, Yemataw Addis
Electroanalytical techniques are powerful tools in biological sensing because of their sensitivity and versatility. In recent decades, great attention has been given to the fabrication of electroactive nanomaterial-based biosensors. In this context, carbon quantum dots (CQDs) have received special attention and have been used to develop many sensors because of their remarkable advantages such as high photostability, high solubility and stability in water, biocompatibility, high photoluminescence emission intensities, and simple methods of synthesis. Since they are very small in size, they have high surface area to volume ratios which in turn can allow good catalytic activities of the working electrodes in electrochemical reactions. Being motivated by these advantages, in this work we prepared two types of carbon quantum dots (CQD-COOH and CQD-NH2) and used them to modify screen printed carbon electrodes (SPCEs) for detection of Troponin I (cTnI). These carbon quantum dot – modified SPCE immunosensors have offered promising results for the determination of cTnI with a limit of detection 62 pg/mL and 171 pg/mL, respectively. This simple approach to sensor design further offers valuable insights into the construction of paper based printed electrodes modified with new carbon-based nanomaterials as immunosensors for detection of other biomarkers of various diseases. © 2025 The Authors. ChemElectroChem published by Wiley-VCH GmbH.
Names of public memory spaces as sites of coloniality, cultural erasure, and downscaling in linguistic landscapes of Northern Zambia
(Routledge, 2025) Simungala, Gabriel; Banda, Felix
This article problematises the names of two spaces of public memory in northern Zambia (South-Central Africa), the Moto Moto Museum and the Kalambo Falls Heritage Site, to illustrate the unequal power dynamics in place. It argues that both names are rooted in coloniality, perpetuating the erasure and downscaling of local historical voices and narratives. Moto Moto upscales the legacy of White religious figures while erasing the contribution of indigenous actors. Similarly, Kalambo reflects colonial control through the normalisation of mispronounced African words, stripping them of their original meaning and diminishing local cultural heritage. The article concludes with an exploration of how names of spaces of public memory in the linguistic landscape may carry a colonial heritage that surreptitiously reinforces the dominance of colonial narratives while diminishing local historical narratives and voices, resulting in the distortion of history and the sentiments of local people. © 2025 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Foreground removal in HI 21 cm intensity mapping under frequency-dependent beam distortions
(EDP Sciences, 2026) Spinelli, Marta; Gkogkou, Athanasia; Bonjean, Victor
Context. Neutral hydrogen (HI) intensity mapping with single-dish experiments is a powerful approach for probing cosmology in the post-reionization epoch. It is challenging to extract it, however, because of the bright foregrounds, which are stronger than the HI signal by more than four orders of magnitude. While all methods perform well when a Gaussian beam is assumed that is degraded to the lowest resolution, most methods degrade significantly in a more realistic beam model. Aims. The complexity introduced by frequency-dependent beam effects means that we need methods that explicitly account for the instrument response. We investigate the performance of SDecGMCA. This method extends DecGMCA to spherical data by combining sparse component separation with beam deconvolution. Our goal is to evaluate this method in comparison with established foreground removal techniques by assessing its ability to recover the cosmological HI signal from single-dish intensity mapping observations under varying beam conditions. Methods. We used simulated HI signals and foregrounds informed by existing observational and theoretical models that cover the frequency ranges relevant to MeerKAT and SKA-Mid. The foreground removal techniques we tested fall into two main categories: model-fitting methods (polynomial and parametric), and blind source separation methods (PCA, ICA, GMCA, and SDecGMCA). Their effectiveness was evaluated based on the recovery of the HI angular and frequency power spectra under progressively more realistic beam conditions. Results. While all methods performed adequately under a uniform degraded beam, SDecGMCA remained robust when frequency-dependent beam distortions were introduced. For an oscillating beam, SDecGMCA suppressed the spurious spectral peak at kν-0.3 and achieved an accuracy of 5% at intermediate angular scales (10-<-<-200); it outperformed other methods. Furthermore, the masking of bright Galactic regions significantly improved the recovery of the HI signal, in particular, for SDecGMCA, which benefited most when contaminated lines of sight were excluded. The beam inversion, however, remained intrinsically unstable beyond 200. This sets a practical limit on the method. Conclusions. Our findings highlight the limitations of simple fitting and standard blind source separation methods for realistic beam effects, and they establish SDecGMCA as a particularly promising approach for future single-dish intensity mapping surveys. Its robustness for various beam models, combined with the improvements that can be achieved through masking strategies and forthcoming refinements to its thresholding scheme, suggest that SDecGMCA might provide reliable spherical harmonics reconstructions of the HI power spectrum in upcoming experiments.