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    Characterization of high entropy ceramic powders: band gap evolution with temperature of calcination
    (MDPI, 2024-03-22) Dallaev, Rashid; Spusta, Tomáš; Allaham, Mohammad Mahmoud; Spotz, Zdeněk; Sobola, Dinara
    This manuscript presents a comprehensive exploration of the band gap structure in (CoCrFeNiMn)3O4 powders through a series of experimental investigations. The combined use of optical techniques, and X-ray photoelectron spectroscopy in this study offers a comprehensive characterization of the band gap structure in (CoCrFeNiMn)3O4 powders. The findings contribute to the understanding of the material's electronic properties and pave the way for potential applications in electronic and optical devices.
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    Combination NIPS/TIPS Synthesis of -Fe2O3 and /-Fe2O3 Doped PVDF Composite for Efficient Piezocatalytic Degradation of Rhodamine B
    (MDPI, 2023-10-02) Magomedova, Asiyat; Rabadanova, Alina; Shuaibov, Abdulatip; Selimov, Daud; Sobola, Dinara; Rabadanov, Kamil; Giraev, Kamal M.; Orudzhev, Farid
    Highly porous membranes based on polyvinylidene fluoride (PVDF) with the addition of nanoscale particles of non-magnetic and magnetic iron oxides were synthesized using a combined method of non-solvent induced phase separation (NIPS) and thermo-induced phase separation (TIPS) based on the technique developed by Dr. Blade. The obtained membranes were characterized using SEM, EDS, XRD, IR, diffuse reflectance spectroscopy, and fluorescent microscopy. It was shown that the membranes possessed a high fraction of electroactive phase, which increased up to a maximum of 96% with the addition of 2 wt% of alpha-Fe2O3 and alpha/gamma-Fe2O3 nanoparticles. It was demonstrated that doping PVDF with nanoparticles contributed to the reduction of pore size in the membrane. All membranes exhibited piezocatalytic activity in the degradation of Rhodamine B. The degree of degradation increased from 69% when using pure PVDF membrane to 90% when using the composite membrane. The nature of the additive did not affect the piezocatalytic activity. It was determined that the main reactive species responsible for the degradation of Rhodamine B were (OH)-O-center dot and O-center dot(2)-. It was also shown that under piezocatalytic conditions, composite membranes generated a piezopotential of approximately 2.5 V.
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    Analysis of processing efficiency, surface, and bulk chemistry, and nanomechanical properties of the Monel® alloy 400 after ultrashort pulsed laser ablation
    (IOP Publishing Ltd, 2024-01-01) Ronoh, Kipkurui; Novotný, Jan; Mrňa, Libor; Knápek, Alexandr; Sobola, Dinara
    Monel (R) alloy 400 has excellent corrosion resistance and finds applications in marine industries. The processing of marine components requires high processing efficiency and a quality finish. Hence, this research aims to investigate the effects of the laser processing parameters such as laser fluence, scanning velocity, hatching distance, and the scanning pass on the ablation rates and efficiency, chemistry, and nanomechanical properties of the Monel (R) alloy 400 after pulsed picosecond (ps) laser ablation. From the experimental findings, the ablation depth increases as the laser fluence increases while decreasing as the scanning velocity increases. Surface roughness was noted to increase as the laser fluence increased. The findings demonstrated that the ablation rate increases as laser fluence increases while ablation efficiency decreases. Energy dispersive x-ray spectroscopy (EDX) showed that the elemental composition of laser-ablated zones is almost similar to that of the polished sample. X-ray spectroscopy (XPS) shows that the outer layer on the surface of Monel (R) alloy 400 is composed of NiO and CuO. The hardness and Young's modulus of the laser-processed alloy were found to be less than those of the bulk material. This study can be used to establish optimal processing parameters for the ultrafast ps laser processing of materials to achieve high ablation efficiency with a high-quality surface finish for industrial applications.
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    Oxygen Vacancies and Surface Wettability: Key Factors in Activating and Enhancing the Solar Photocatalytic Activity of ZnO Tetrapods
    (MDPI, 2023-11-15) Orudzhev, Farid; Muslimov, Arsen; Selimov, Daud; Gulakhmedov, Rashid; Lavrikov, Alexankder; Kanevsky, Vladimir; Gasimov, R.D.; Krasnova, Valeryia; Sobola, Dinara
    This paper reports on the high photocatalytic activity of ZnO tetrapods (ZnO-Ts) using visible/solar light and hydrodynamic water flow. It was shown that surface oxygen defects are a key factor in the photocatalytic activity of the ZnO-Ts. The ability to control the surface wettability of the ZnO-Ts and the associated concentration of surface defects was demonstrated. It was demonstrated that the photocatalytic activity during the MB decomposition process under direct and simulated sunlight is essentially identical. This presents excellent prospects for utilizing the material in solar photocatalysis.
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    A Brief Review of Bone Cell Function and Importance
    (MDPI, 2023-11-05) Šromová, Veronika; Sobola, Dinara; Kaspar, Pavel
    This review focuses on understanding the macroscopic and microscopic characteristics of bone tissue and reviews current knowledge of its physiology. It explores how these features intricately collaborate to maintain the balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption, which plays a pivotal role in shaping not only our physical framework but also overall health. In this work, a comprehensive exploration of microscopic and macroscopic features of bone tissue is presented.