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Coupled effects of morphology/length scale of the microstructure and microsegregation on the corrosion behaviour of a single-phase Zn-1wt%Cu alloy

Next Materials

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Next materials 2025年 8卷

作者： Miranda, Romulo S. Vida, Talita Ligeiro, Henrique S. Cheung, Noé Simões, Fábio R. Garcia, Amauri brito, Crystopher Postgraduate Program in Engineering São Paulo State University Guaratinguetá Brazil Department of Aeronautical Engineering School of Engineering/São Paulo State University São João da Boa Vista Brazil Department of Manufacturing and Materials Engineering University of Campinas Campinas Brazil Institute of Marine Science Federal University of São Paulo Santos Brazil

Zn-Cu alloys are promising for biomaterials due to their unique properties. Unlike most metallic alloys, Zn-Cu exhibits a partition coefficient greater than 1, leading to solvent segregation. This study aims to explore how microsegregation and cellular microstructure affect the corrosion behaviour of a Zn-1wt%Cu alloy. Three specimens, with cellular spacings of approximately 8, 16, and 32 µm, were extracted from a directionally solidified casting. Electrochemical Impedance Spectroscopy and Potentiodynamic Polarization techniques were used to assess the corrosion performance in NaCl solutions. The results showed that coarser cellular structures demonstrated higher corrosion resistance, evidenced by greater charge transfer resistances and lower current densities. Corrosion initiated at the Cu-poor cellular boundaries, acting as anodic regions, and became more severe in finer microstructures. In contrast, larger cells with fewer boundaries exhibited less generalised corrosion, confirming that microstructural coarsening improves corrosion resistance. © 2025 The Authors

关键词： biodegradable Zn-Cu alloys Corrosion behaviour in NaCl Electrochemical performance of biomaterials Galvanic corrosion mechanisms Microstructural refinement

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Waste Valorization from brazilian Nepheline Syenite Processing as a Strategic Approach to Advancing the Circular Economy

SSRN

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SSRN 2023年

作者： Santos, Diego Haltiery Rosa, Laura Pereira Alves, Cleidson Rosa Simão, Lisandro Arcaro, Sabrina Klegues Montedo, Oscar Rubem Raupp-Pereira, Fabiano Graduate Program in Materials Science and Engineering University of the Extreme South of Santa Catarina Criciúma88806-000 Brazil Department of Civil Engineering Federal Institute of Santa Catarina Criciúma88813-600 Brazil Research Group on Sustainability and Waste Management Postgraduate Program in Environmental Technology University of Ribeirão Preto Ribeirão Preto14096-900 Brazil Brazil

The growing disparity between the high extraction of natural resources and low use of waste as alternative mineral resources will aggravate the scarcity of natural reserves. Therefore, the current linear economy model must be converted to sustainable economic models, such as the circular economy. To achieve this transition, it is important that waste recovery strategies are implemented with a continuous search for solutions for these materials. Thus, this study investigates the waste from the processing of nepheline syenite stone, to promote its valorization as an alternative mineral resource. The classification, potentiality, quantity/viability and applicability (CPQvA) criteria are used as tools to aid decision-making for the waste valorization. The environmental, physical, chemical, morphological, and durability characteristics of nepheline syenite waste (NSW) are analyzed. The results showed evidence for the substitution of NSW for up to 100% of fine aggregates and 25% of Portland cement in civil construction. Furthermore, NSW yields recoveries of more than 90% of potassium for use in agriculture, and up to 70% of iron ore for use in steelworks. Therefore, the results indicate that NSW is viable for different applications, contributing to industrial symbiosis and a strategy for advancing the circular economy. © 2023, The Authors. All rights reserved.

关键词： Sustainable development

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Challenges for and Pathways toward Li-Metalbased All-Solid-State batteries

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ACS ENERGY LETTERS 2021年第4期6卷 1399-1404页

作者： Albertus, Paul Anandan, Venkataramani ban, Chunmei balsara, Nitash belharouak, Ilias buettner-Garrett, Josh Chen, Zonghai Daniel, Claus Doeff, Marca Dudney, Nancy J. Dunn, bruce Harris, Stephen J. Herle, Subramanya Herbert, Eric Kalnaus, Sergiy Libera, Joesph A. Lu, Dongping Martin, Steve McCloskey, bryan D. McDowell, Matthew T. Meng, Y. Shirley Nanda, Jagjit Sakamoto, Jeff Self, Ethan C. Tepavcevic, Sanja Wachsman, Eric Wang, Chunsheng Westover, Andrew S. Xiao, Jie Yersak, Thomas Department of Chemical and Biomolecular Engineering University of Maryland College Park Maryland 20742 United States Ford Motor Company Dearborn Michigan 48121 United States Mechanical Engineering Department University of Colorado Boulder Colorado 80309 United States Department of Chemical and Biomolecular Engineering and Lawrence Berkeley National Laboratory Materials Sciences Division University of California Berkeley California 94720 United States Energy and Transportation Science Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 United States Solid Power Inc. Louisville Colorado 80027 United States Chemical Sciences and Engineering Division Argonne National Laboratory 9700 South Cass Avenue Argonne Illinois 60439 United States Lawrence Berkeley National Laboratory Energy Storage and Distributed Resources Division University of California Berkeley California 94720 United States Department of Materials Science and Engineering University of California Los Angeles California 90095 United States Applied Materials Inc. 3225 Oakmead Village Drive B12_2F6 Santa Clara California 95054 United States Department of Materials Science and Engineering Michigan Technological University Houghton Michigan 49931 United States Energy and Environmental Directorate Pacific Northwest National Laboratory Richland Washington 99352 United States Department of Materials Science & Engineering Iowa State University of Science & Technology Ames Iowa 50011 United States Woodruff School of Mechanical Engineering and School of Materials Science and Engineering Georgia Institute of Technology Atlanta Georgia 30332 United States Department of NanoEngineering and Materials Science and Engineering Program University of California San Diego La Jolla California 92093 United States Department of Materials Science and Engineering and Department of Mechanical Engineering University of Michigan Ann Arbor Michigan 48109 United States Chemical and Materials Systems Laborat

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Effects of Incident Angle on Single-Event Leakage Current Degradation in Heavy-Ion Irradiated 1800 v and 4500 v SiC Power MOSFETs

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IEEE Transactions on Nuclear science 2025年

作者： Sengupta, A. Martinella, C. ball, D.R. Niskanen, K. Senarath, A.S. Islam, S. Harris, P.M. Hutson, J.M. Osheroff, J.M. Sternberg, A.L. Kettunen, H. Kosier, S.L. Grossner, U. Javanainen, A. Galloway, K.F. Schrimpf, R.D. Witulski, A.F. Zürich8092 Switzerland Vanderbilt University Interdisciplinary Materials Science Program NashvilleTN37235 United States Lipscomb University Electrical and Computer Engineering Department NashvilleTN37204 United States NASA/GSFC Code 561.4 GreenbeltMD20771 United States Vanderbilt University Electrical Engineering and Computer Science Department B 351825 NashvilleTN37235 United States University of Jyväskylä Department of Physics Jyväskylä40014 Finland

Experimental heavy-ion responses of two variants of SiC power MOSFETs are evaluated. The devices have similar epitaxial thickness but different doping. The higher doping in the epitaxial region results in lower breakdown voltage, and typically leads to a lower threshold drain voltage at which single-event leakage current (SELC) occurs. Furthermore, the heavy-ion-induced SELC degradation in the drain and gate currents of the SiC MOSFETs exhibit a strong dependence on the heavy-ion's angle of incidence. The devices' behavior significantly alters when irradiated with heavy-ions at different incident angles under the same fixed bias and total fluence, as also confirmed by 3-D Technology Computer Aided Design (TCAD) simulations. © 1963-2012 IEEE.

关键词： Power MOSFET

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Performance of atrial conduction velocity algorithms with error-prone clinical measurements for the identification of atrial fibrosis

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Computers in biology and Medicine 2025年 191卷 110119-110119页

作者： Gharaviri, Ali Vigneswaran, Vinush Vickneson, Keeran Roney, Caroline Corrado, Cesare Coveney, Sam Maciunas, Kestutis bodagh, Neil Klis, Magda Kotadia, Irum Sim, Iain Whitaker, John bishop, Martin Niederer, Steven O'Neill, Mark Williams, Steven E. Centre for Cardiovascular Science The University of Edinburgh United Kingdom School of Biomedical Engineering and Imaging Sciences King's College London United Kingdom School of Engineering and Materials Science Queen Mary University of London United Kingdom National Heart & Lung Institute - Faculty of Medicine Imperial College London United Kingdom Heart Rhythm Research Brussels Postgraduate Program in Cardiac Electrophysiology and Pacing Vrije Universiteit Brussel Brussels Belgium Heart Rhythm Management Centre Universitair Ziekenhuis Brussel Brussels Belgium Brussels1050 Belgium

Introduction: Measuring conduction velocity, as a direct consequence of fibrosis, may provide a better method to localise fibrotic regions. This study aims to assess established cardiac conduction velocity calculation methods (Triangulation, Polynomial Surface Fitting, and Radial basis Function) in identifying areas of conduction slowing caused by fibrosis, considering realistic measurement errors. Method: Using a human left atrium computational model, atrial activation was simulated. Each conduction velocity calculation method's performance was evaluated under uncertainties in mapping point density, local activation time assignment and electrode locations by comparing calculated conduction velocity to ground truth conduction velocity derived from high-resolution simulated atrial activation. Results: All methods agreed well with ground truth conduction velocity maps in noise-free, high-density sampling conditions. However, Triangulation and Polynomial Surface Fitting methods showed susceptibility to noise, exhibiting significant errors under moderate to high noise levels. Radial basis Function method demonstrated greater robustness to noise and reduced sampling density. Fibrotic region identification accuracy was high under ideal conditions for all methods but declined with increasing noise, with the Radial basis Function method maintaining superior performance. Conclusion: While all methods accurately estimate conduction velocity under ideal conditions, the Radial basis Function method shows robustness to a realistic clinical noise, hence making it the most suitable to identify fibrotic regions. © 2025

关键词： Triangulation

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Study of doxorubicin release carried out by pH-responsive chitosan-alginate hydrogels

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Journal of Molecular Liquids 2025年 429卷

作者： Oliveira, Thayane Portela da Silva, Jhaemely Gabrielly Vieira Costa, Paloma Maia de Oliveira, Maykol Christian Damasceno Coelho, Ronaldo Cunha Santos Nascimento, Ariane Maria Silva Silva-Filho, Edson Cavalcanti dos Santos, Francisco Eroni Paz Muniz, Edvani Curti Postgraduate Program in Engineering and Materials Science Federal University of Piauí PI Teresina64049550 Brazil Physics Department Federal University of Piauí PI Teresina64049550 Brazil Department of Teacher Training Instituto Federal do Piauí PI Teresina64053-390 Brazil Chemistry Department Federal University of Piauí PI Teresina64049550 Brazil Chemistry Department State University of Maringá PR Maringá87020-900 Brazil

The use of polysaccharides in drug delivery systems has attracted increasing interest due to their functional properties. Among these, alginate (ALG) and chitosan (CH) are promising candidates for sustained drug delivery as they respond to pH, ensuring that the compound is released in a desired area. In this research physical hydrogels based on alginate and chitosan (ALG/CH) were prepared by varying the synthesis parameters (ALG at ALG/CH ratio, pH and speed stirring) and the effects of such parameters on hydrogels’ chemical and physical structure were accessed through several techniques. Also, the effects synthesis parameters on fractional release (Fmax), half time (t1/2) and percentage encapsulation efficiency (EE%), as the evaluated responses, were statically measured using a factorial design. Analysis through Raman and FTIR spectroscopies revealed the modes and bands corresponding to the precursors, confirming the formation of physically cross-linked hydrogels. The porous structure of the materials was confirmed by scanning electron microscopy (SEM). The swelling capacities of the hydrogels were analyzed at different pHs (5.4 and 7.4) and demonstrated that absorption increases in slightly acidic media. TG/DTG and Micro-CT analyzes of the sample with the greatest swelling showed that the degradation of the hydrogel occurs in two endothermic events and that the material possesses several sized and interconnected pores. The doxorubicin (DOX) release study showed that the release rate is higher as the higher proportion of CH relative to ALG. The factorial design analysis indicated the statistically significant factors in the DOX release tests. Thus, the results suggest that ALG/CH hydrogels can be tuned during their preparation to achieve optimal structure for pH-responsive to be applied for DOX releasing system. © 2025 Elsevier b.V.

关键词： Microgels

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Understanding the effect of preparation technique and compaction pressure on the microstructure, sinterability and mechanical properties of the Cu-20 wt% WC composite prepared with recycled WC

Journal of Alloys and Compounds Communications

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Journal of Alloys and Compounds Communications 2025年 6卷

作者： Rafael A. Raimundo Franciné A. Costa Marco A. Morales Daniel A. Macedo Angelus G.P. Silva Uílame U. Gomes Federal University of Paraíba Department of Materials Science and Engineering João Pessoa PB 58051-900 Brazil TEMA – Centre for Mechanical Technology and Automation Department of Mechanical Engineering University of Aveiro Aveiro 3810-193 Portugal Mechanical Engineering Postgraduate Program UFRN Natal 59078-970 Brazil Department of Theoretical and Experimental Physics UFRN Natal 59078-970 Brazil Materials Science and Engineering Postgraduate Program UENF Campos dos Goytacazes 28015-620 Brazil Materials Science and Engineering Postgraduate Program UFRN Natal 59078-970 Brazil

The study investigated the impact of different preparation techniques (Mechanical Mixing - MM and High Energy Milling - HEM) and compaction pressures on the microstructure, sinterability and mechanical properties of the Cu-20 %WC composite using recycled WC. The results indicated that HEM promotes greater homogeneity, dispersion and refinement of the WC phase in copper, resulting in denser and more uniform microstructures after sintering. Although higher pressures increased the density of green compacts, they reduced densification during sintering, especially for powders prepared by MM, due to the segregation of the Cu and WC phases. On the other hand, compacts sintered with HEM powders prsented higher Vickers microhardness and better magnetic properties, attributed to the uniform distribution of WC particles and the increase in the interaction between the phases. Furthermore, the study highlights the influence of metallic impurities (Fe, Co and Ni) on the magnetic properties of the composite materials.

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Reversible Actuation of α-borophene Nanoscrolls

arXiv

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arXiv 2023年

作者： Fabris, Guilherme S.L. Galvão, D.S. Paupitz, Ricardo Postgraduate Program in Materials Science and Engineering Federal University of Pelotas RS Pelotas96010-610 Brazil Applied Physics Department State University of Campinas SP Campinas13083-970 Brazil Sao Paulo State University - Unesp Physics Department SP Rio ClaroCEP-13506-900 Brazil

In this work, we proposed and investigated the structural and electronic properties of boron-based nanoscrolls (armchair and zigzag) using the DFTb+ method. We also investigated the electroactuation process (injecting and removing charges). A giant electroactuation was observed, but the results show relevant differences between the borophene and carbon nanoscrolls. The molecular dynamics simulations showed that the scrolls are thermally and structurally stable for a large range of temperatures (up to 600K) and the electroactuation process can be easily tuned and can be entirely reversible for some configurations. © 2023, CC bY.

关键词： Molecular dynamics

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Eco-Friendly High Entropy Oxide Rock-Salt Type Structure for Oxygen Evolution Reaction Obtained by Green Synthesis Using Red Seaweed (Rhodophyta)

SSRN

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SSRN 2024年

作者： Santos, Jakeline RAIANE DORA DOS Raimundo, Rafael A. de Oliveira, João F.G.A. Hortencio, Johnnys da S. Loureiro, Francisco J.A. Macedo, Daniel A. Morales, Marco A. Gualandi, Isacco Tonelli, Domenica Gomes, Uílame U. Materials Science and Engineering Postgraduate Program UFRN Natal59078-970 Brazil Department of Industrial Chemistry "Toso Montanari" Industrial Chemistry UNIBO V.le Risorgimento 4 Bologna40136 Italy Department of Theoretical and Experimental Physics Federal University of Rio Grande do Norte UFRN Natal59078-970 Brazil Gleb Wataghin Institute of Physics - R. Sérgio Buarque de Holanda 777 - Cidade Universitária Campinas13083-859 Brazil Department of Chemistry Federal University of Paraíba UFPB João Pessoa58.051-900 Brazil TEMA - Centre for Mechanical Technology and Automation Mechanical Engineering Department University of Aveiro 3810-193 Portugal LASI - Intelligent Systems Associate Laboratory Portugal Materials Science and Engineering Postgraduate Program Federal University of Paraíba UFPB João Pessoa58051-900 Brazil

Global energy consumption increases year after year, causing the depletion of non-renewable sources. According to the International Energy Agency (IEA), global demand for electrical energy is expected to increase by 3.3% in 2024. Therefore, developing new renewable sources is urgent, including new devices for energy storage and conversion, particularly those governed by electrochemical reactions. Water splitting is a clean and sustainable technology capable of facing this issue by producing oxygen and hydrogen from water and electricity. However, a problem related to this technology is the slow kinetics, making it necessary to develop new electrocatalysts with high electrochemical performance. To meet this requirement, this work deals with for the first time a high entropy oxide with rock-salt structure synthesized by a green solgel synthesis using red seaweed (Rhodophyta) as polymerizing agent. Solgel synthesis allows the large-scale production of nanomaterials with high uniformity and dispersion of the chemical elements involved. The literature, which discussed the production of these oxides, reveals that agents harmful to the environment are applied during the synthesis steps, including sodium hydroxide, acetic acid, hexadecyltrimethylammonium bromide, urea, and ammonia. The composition of the high entropy oxide is (Mg0.2 Ni0.2 Co0.2 Cu0.2 Zn0.2 )O, it displays a low overpotential (336 mV vs. RHE at 10 mA cm-2 ), Tafel slope of 68 mV dec-1 , and excellent durability. The electrochemical performance of the high entropy oxide prepared in this work is superior to other electrocatalysts of the same class that were produced using transition metal-based precursors. © 2024, The Authors. All rights reserved.

关键词： Entropy

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Thermo-optical properties of luminescent carbon dots produced from biomass of Orbignya speciosa (babassu coconut)

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Journal of Molecular Liquids 2025年 423卷

作者： Oliveira, Maykol Christian Damasceno Silva, Adriano Almeida Silva-Silva, Tânia Patrícia Silva, Jhaemely Gabrielly Vieira da Silva Júnior, José Ferreira Sanchez, David bell, Maria José Valenzuela Garcia, Hans Anderson Viana, bartolomeu Cruz Terrones, Mauricio Costa, Rubens Silva Santos, Francisco Eroni Paz Physics Department Federal University of Piauí PI 64049550 Brazil Postgraduate Program in Engineering and Materials Science Federal University of 64049550 PI Teresina Brazil Department of Physics and Center for 2-Dimensional and Layered Materials The Pennsylvania State University University ParkPA16802 United States Federal University of Juiz de Fora Institute of Exact Sciences Department of Physics University Campus - UFJF/ ICE/ Department of Physics Martelos MG Juiz de Fora36036330 Brazil Federal Institute of Piauí Paranaíba Campus PI Parnaíba64211145 Brazil

Exploring materials with high nonlinearities derived from organic and biological sources has become a significant focus within the scientific community. Among these materials, carbon dots (CDs) synthesized from biomass have emerged as promising candidates due to their sustainable and cost-effective production methods. This study synthesized CDs from Orbignya speciosa (babassu coconut) biomass via a hydrothermal route. UV–visible absorption and Infrared spectrum analysis revealed characteristic bands associated with the formation of dots and the electronic transitions π–π* from aromatic C=C bonds in the CDs’ core and n–π* transitions of surface carboxylate groups, photoluminescence as a function of temperature and lifetime decay measurements show that the photoluminescence mechanisms in these materials due this transitions comes from electronic indirect transitions from primary sources of the core and carbonyl boundings in the surface of the material, additionally, to this the Dynamic Light Scattering (DLS) and Transmission Electronic Microscopy (TEM) give the structural properties of the dots, amorphous and with a large size distribution with a mean size of (21 ± 1) nm. Thermal lens spectroscopy (TLS) was employed to determine the material's thermal diffusivity, reaching a maximum value of 2.03 × 10−7 m2/s as a function of dilution. The Z-scan technique under continuous wave (CW) excitation at 532 nm investigated nonlinear optical properties, yielding a maximum thermal nonlinear refractive index (n2(th)) value of −5.87 × 10−5 esu. Furthermore, the photothermal efficiency of the CDs was quantified at 505 nm, demonstrating a high absorption efficiency of 94.9 %, suggesting their potential application in photothermal therapies. These findings contribute to understanding babassu coconut CDs’ thermo-optical behavior, highlighting their promise for various practical applications, particularly in biomedicine. © 2025 Elsevier b.V.

关键词： Refractive index

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