Mechanical Engineering, Surfaces, Coatings and Films, Renewable Energy, Sustainability and the Environment
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Scopus Publications
Scopus Publications
A Morphological Study of Restoration of Damaged Hair Fiber With Chemical Treatments Using Microscopy Techniques L. P. A. Mauricio, R. A. D. Cunha, S. M. Alves Microscopy Research and Technique, 2026 This paper analyses hair restoration products currently on the market that treat chemically processed hair. This study measured the restoration of structural integrity in hair samples from both chemically damaged hair (chemically relaxed, bleached, and chemically color‐treated) and virgin hair. Hair samples were exposed to two hair restoration products (low‐ and high‐cost), formulated with ingredients from two different price points. This analysis is essential because of the challenges in finding scientific information on treatment protocols for processes that can damage hair. The effectiveness of these treatments was evaluated by assessing the structural damage caused by the chemical processes using scanning electron microscopy (SEM), atomic force microscopy (AFM), and Raman spectroscopy. The results indicated that chemical processes alter Keratin's conformation, resulting in detrimental effects on the hair fiber. The cumulative impact of these processes chemically and physically modifies the hair's structure. The findings revealed that the most effective treatment was the High Cost (HC) product, which contains coconut oil and glycerol. This treatment was particularly effective for hair that had undergone significant degradation, particularly from bleaching followed by color treatment. Remarkably, this high‐cost (HC) product produced a higher level of morphological restoration than expected, even aiding in the recovery of cuticular cells.
Synergistic effect of CuO/MoS2 nanoparticles as lubricant additives under boundary lubrication conditions Raaid Yassin, Salete Alves, Ali Hassanpour, Cayetano Espejo, Ardian Morina Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology, 2026 Lubricants containing nanoparticles have garnered significant attention due to their potential to improve the tribological performance of systems operating in demanding environments. In the current study, the enhanced stability of copper oxide (CuO) and molybdenum disulphide (MoS 2 ) nanoparticles (NPs) and their tribological performance, when used as lubricant additives, were experimentally tested to evaluate their synergistic effect on friction and wear performance. The oleic acid (OA) was used as a surface modifier agent to enhance dispersion stability. The influence of oleic acid on nanoparticle dispersion was evaluated using Dynamic Light Scattering (DLS) and Zeta Potential (ZP) techniques. The surface of nanoparticles was characterised by Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA). The tribological performance of the more stable nanolubricant, including friction reduction and wear resistance, was evaluated using a pin-on-reciprocating plate test rig. Surface characterisation of the wear tracks was performed using White Light Interferometry (WLI), Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM/EDX), X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM) to understand how the improved stability affected the worn surfaces and tribofilm properties. NPs stability study confirmed that the best stability could be achieved with concentrations of 1% CuO/MoS 2 NPs and 1.5 wt. % OA. Tribology results indicated that CuO and MoS 2 NPs individually could reduce friction and wear, whereas their combination exhibited enhanced friction and wear reduction. This synergy in tribological performance has been attributed to the combined effects of nanoparticle size and enhanced dispersion stability, which enable effective nanoparticle entrainment between the contacting surfaces, leading to the formation of a tribofilm that provides anti-wear protection and contributes to friction reduction.
Erosion behavior of turbine blades due to sand and salt particles Ranaildo Gomes da Silva, Pedro Lucas Gomes de Souza Silveira, Rayane Dantas da Cunha, Luiz Guilherme Vieira Meira de Souza, Salete Martins Alves Journal of Composite Materials, 2025 This study investigates the degradation of wind turbine blades (WTBs) exposed to the atmospheric conditions of tropical coastal environments. A wind tunnel experimental methodology was employed to simulate the erosive effects of airborne particulates, focusing on the influence of salt and sand particles. Specimens were subjected to controlled wind speeds and impact angles to assess material wear mechanisms. The results indicated that a 45° impact angle led to increased material loss due to both normal and tangential impact components. The highest mass loss recorded was 0.78% in the salt and sand particles test, while the most significant increase in surface roughness was 1.89 µm at a 90° impact angle, confirming the severe impact of perpendicular erosion. SEM analysis revealed that fiberglass delamination contributed to the degradation process, particularly in high-impact scenarios. These findings provide insights into material behavior under extreme coastal conditions and emphasize the need for improved protective coatings and maintenance strategies for WTBs in tropical maritime regions.
Design and Experimental Setup of an Innovative Tribometer Aiming to Evaluate Small Quantities of Lubricants Lenine Marques de Castro Silva, Adilson José de Oliveira, Aylla Maria Alencar Rocha, José Josemar de Oliveira Junior, Salete Martins Alves Lubricants, 2025 The proposed tribometer design evaluates lubricants’ lubricating and wear protection properties at the interface of a loaded set of gears. However, this tribometer configuration and testing procedure described in standard ISO 14645-1 does not limit the tribological studies of gear test rigs. This study aimed to design and manufacture a mechanical transmission test rig capable of investigating the tribological condition of a lubricated enclosed gears transmission. The methodology consisted of (i) a definition of the test rig’s requirements; (ii) downsizing the main subassemblies present in the ISO 14635-1 test rig; (iii) designing innovative subassemblies; (iv) an instrumentation and data acquisition system, and (v) setup testing. The proposed system is suitable for evaluating small quantities of lubricants, allowing the analysis of special lubricants such as nanolubricants and ionic liquids in development for gearbox applications. Also, the dynamic loading avoids interruption in the test, providing results closer to working conditions. The experimental test evaluated the lubrication ability of two different base oils simultaneously under various loading conditions. Also, monitoring vibration signals helped identify the appearance of damage on the gear surface.
Failure analysis of gear using continuous wavelet transform applied in the context of wind turbines Alexandre Medeiros, Raphael Cardoso, José Oliveira Júnior, Salete Alves Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology, 2024 One of the main reasons for failure in the wind turbine is the wear between the gear teeth during the power conversion and changes in the rotation speed, which is also generally associated with changes in the lubrication regimes. In this sense, vibration and signal analysis are frequently used in predictive maintenance as they usually permit the identification of deviations in the proper functioning of the equipment. Thus, this work aims to apply the continuous wavelet transform (CWT) to correlate gear wear and vibration signals, using visual and straightforward analysis. An experimental setup of a gear system was used to analyze vibration signals from different tooth gear damages. Gears with different levels and modes of damage were used in order to evaluate the sensitivity of vibration signals to them. The features from vibration signals were extracted by Morlet wavelet analysis. Results demonstrate that the proposed method accurately detected the early failure by visualization in frequency–time maps.
The lubricity analysis of cutting fluid emulsions Erinéia da Silva Santos, Ana Paula de Paula Camargo, Edália Azevedo de Faria, Francisco Adriano Ferreira de Oliveira Junior, Salete Martins Alves, et al. Materials Research, 2017
Analyze of influence of base oils and additives EP on lubrication of metallic surfaces Proceedings International Brazilian Conference on Tribology, 2010
Erratum: Environmental adequacy of machining processes using Cleaner Production as strategy of environment management (Produçã (2007) vol. 17 (1) (128-138)) Producao, 2007
