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Synthesis, structural characterization, biological and in silico evaluation of halogenated Schiff bases as potential multifunctional agents
(Elsevier, 2026-02) Nthehang, Tsholofelo S.; Waziri, Ibrahim; Yusuf, Tunde Lewis; Oselusi, Samson Olaitan; Muller, Alfred J
Please read abstract in the article. HIGHLIGHTS • Three new halogen substituted Schiff bases (SB1, SB2, and SB3) were synthesized. • Detailed spectroscopic and theoretical investigations were carried out. • All compounds were tested for cyto-toxicity, antioxidant, and antibacterial. • Biological study results revealed SB1 and SB3 as the most potent across all the assays, with SB1 been more superior.
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A MeerKAT study of a neutral hydrogen rich grouping of galaxies with megaparsec-scale filamentary-like structure
(EDP Sciences, 2025-09) Lawrie, G.D.; Deane, Roger; Dave, R.
CONTEXT. Environmental effects within cosmological overdensities, such as galaxy groups and clusters, have been shown to impact galaxies and their cold gas reservoirs and thereby provide constraints on galaxy evolution models. Galaxy groups foster frequent galaxy-galaxy interactions, making them rich environments in which to study galaxy transformation. AIMS. In this work, we study a serendipitously discovered large overdensity of neutral hydrogen (H I) galaxies at z ∼ 0.04. The galaxies appear to lie in a filamentary-like structure of megaparsec scale. Using MeerKAT’s angular resolution and field of view, we were able to spatially resolve the H I galaxies while simultaneously probing large-scale structure. METHODS. The H I and sub-arcsec Dark Energy Survey (DES) imaging have revealed a large number of both interacting and disturbed galaxies in this collective group. MeerKAT data enabled us to derive H I masses and investigate interacting galaxies. We used DES and Wide-field Infrared Survey Explorer (WISE) data to quantify the star formation rates, stellar masses, and stellar morphologies of member galaxies and compared these with field scaling relations. To place this discovery and the environmental effects in context, we used the SIMBA cosmological hydrodynamical simulation to investigate the prevalence of qualitatively similar H I overdensities and their large-scale morphological properties. This enabled us to make a prediction of how frequently such structures might be serendipitously discovered with MeerKAT and SKA-Mid H I observations in comparable observation time. RESULTS. The combination of spatially resolved H I data and optical imaging revealed a group rich in interactions, suggesting environmental processes are already shaping galaxy properties within the structure. CONCLUSIONS. More of these serendipitous discoveries are expected, and alongside ongoing targeted programmes, they will provide a rich, unbiased sample to study galaxy transformation and enable a MeerKAT H I perspective on large-scale structure, including filaments.
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Sensitivity of the endwall flow in a linear vane cascade to blade fillet geometry
(Elsevier, 2025-09) Shote, Adeola Suhud; Mahmood, Gazi; u14145295@tuks.co.za
Based on the blade chord and inlet velocity, the current computational study uses a linear vane cascade with a large filleted blade-endwall junction with a 2.01 x 105 Reynolds number. Three fillets with related profiles are explored. To evaluate the upshots of geometric differences in a fillet attached to the endwall flow-field, the height and endwall-width of the fillets are changed. The RANS k-ω turbulent model is used in the computations, and the results are compared to experimental results from a similar cascade without the fillet. The computed results of the secondary flow-field in the endwall region along the cascade are compared for baseline (no fillet) and filleted passages. As a result of diminished leading-edge and passage vortices, the fillets lower pitchwise pressure gradients, flow separation, axial vorticity, and overall pressure losses when compared to the baseline. The pros of fillets on endwall secondary flows are however unaffected by fillet's geometric changes.
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Electropolymerization of polyaniline on coated activated carbon derived from human hair as a bilayer electrode for supercapacitor applications
(Elsevier, 2025-09) Adam, Rashed Ali Mohamed; Maphiri, Vusani Muswa; Otun, Kabir Opeyemi; Fasakin, Oladepo; Rutavi, Gift; Thior, Souleymane; Manyala, Ncholu I.; Maphiri, Vusani Muswa; Maphiri, Vusani Muswa; Otun, Kabir Opeyemi; Otun, Kabir Opeyemi; Maphiri, Vusani Muswa; Otun, Kabir Opeyemi; Fasakin, Oladepo; Rutavi, Gift; Thior, Souleymane
In this study, electropolymerization was used to deposit polyaniline (PANI) layer on the surface of coated activated carbon derived from human hair (HH-AC) using nickel foam as conducting substrate via cyclic voltammetry (CV) at different cycle numbers. The bilayer HH-AC/PANI electrode was prepared in a non-acidic medium unlike other conventional electrochemical polymerization methods, and characterized using Raman spectroscopy, UV–visible spectroscopy, scanning electron microscope (SEM), and nitrogen physisorption measurements to determine the chemical composition, electronic structure, surface morphology, and textural properties, respectively. The results showed that a PANI layer was successfully deposited on the surface of HH-AC. The electrochemical evaluation was carried out using CV, galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques in 2.5 M KNO3 neutral electrolyte. The optimal bilayer electrode prepared by 8-cycles and denoted as HH-AC/PANI-8 shows an excellent specific capacitance of 220 F g−1 at a positive potential, which is almost twice of 121 F g−1 for that of pristine HH-AC operated in a three-electrode system. Furthermore, for practical application, a symmetric device comprising HH-AC/PANI-8 bilayer electrode was assembled and tested in a two-electrode system configuration, leading to a specific energy of 28.6 W h kg−1 and a specific power of 800W kg−1, at a specific current of 1 A g−1 and voltage window of 1.6 V. Besides, the capacitance retention of the device remained 83 % after 10,000 cycles at 5 A g−1, indicating a long lifespan. These results suggest that the HH-AC/PANI-8 bilayer electrode is a promising candidate for high-performance supercapacitors.
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Applications of graphitic carbonaceous materials in photosupercapacitors : recent breakthroughs and future perspectives
(Elsevier, 2025-10) Mombeshora, Edwin Tonderai; Muchuweni, Edigar; Ndungu, Patrick Gathura; et.mombeshora@up.ac.za
Photosupercapacitors (PSCs) have recently attracted extensive research interest as one of the most promising energy storage devices owing to their self-charging attributes, small sizes, portability, lightweight, and ability to support emerging wearable electronics. With the recent emergence of high-specific energy density (Es) applications, including powering hybrid and electric vehicles, noteworthy research efforts are centred on increasing electrochemical performance, cost-effectiveness, and cycle lifespan of PSCs. This is being pursued by developing low-cost electrode materials with high reversible capacity and Es. One potential route to advancements in PSCs is turning to graphitic carbonaceous materials as promising electrode materials. Graphitic carbonaceous materials can be favourably derived from waste biomass, offer tailorable porosity and electro-active area, promote exciton dissociation during PSC charging by acting as electron transport layers, function dually as counter electrodes in solar cells and as electrodes in SCs, and are compatible with binder-free designs, among other merits. Therefore, this review focuses on the current understanding of the shortfalls and merits of using graphitic carbonaceous materials in PSCs. It also highlights the challenges and provides recommendations for improvement regarding PSC design, electrolyte selection, material compatibility, binder usage, fabrication processes, characterisation protocols, and components. Finally, the merits, demerits, and prospects of employing graphitic carbonaceous materials to advance PSC sustainability and performance are outlined.