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Numerical investigation on the thermal-nanofluidic flow induced transverse and longitudinal vibrations of single and multi-walled branched nanotubes resting on nonlinear elastic foundations in a magnetic environment

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Partial Differential Equations in Applied Mathematics 2024年 9卷

作者： Yinusa, A.A. Sobamowo, M.G. Adelaja, A.O. Ojolo, S.J. Waheed, M.A. Usman, M.A. Siqueira, Antonio Marcos de Oliveira Campos, Júlio César Costa Ola-Gbadamosi, Ridwan Department of Mechanical Engineering University of Lagos Nigeria Department of Mathematics University of Lagos Nigeria Department of Mechanical Engineering Federal University of Agriculture Abeokuta Nigeria Department of Chemical Engineering University of Lagos Nigeria Chemical Engineering Graduate Program Department of Chemistry Federal University of Viçosa Brazil Universidade Federal de Viçosa Brazil Department of Mechanical Engineering Lagos State University Nigeria

Carbon nanotubes (CNTs) have attracted great attention due to their tremendous mechanical, thermal, structural and electrical properties leading to many promising applications. The unique and interesting properties of CNTs, such as their mechanical and electrical features, have fascinated industries and researchers to implement CNTs for production of different electromechanical devices. However, it is established that the phenomenon of buckling often occurs when CNTs are subjected to compressive loads and their frequencies under vibration are in order of Tera-Hz and Giga-Hz. Moreover, the profound dynamic behaviours of nanotube under the influences of slip when conveying fluid and magnetic field require a serious and meticulous study. Therefore, this study focuses on the vibration analysis of nanofluid-conveying embedded multi-walled branched nanotubes resting on Winkler-Pasternak foundation in a thermal-magnetic environment. Using Euler-Bernoulli theory, Hamilton's principle and nonlocal elasticity theory, fully coupled equations of motion governing the transverse and longitudinal vibrations of the nanotube are developed. Also, the equation of the deformation of the nanotubes as well as the pressure variation in the tubes are developed. Additionally, Navier-Stoke's equation and energy equation for the fluid and nanotube are coupled with the vibration models. The dynamics of the multi-walled carbon nanotubes when coupled with Navier-Stokes and energy equations require meticulous study as it is different from the usual assumption of plug flow. Therefore, in this present work, the developed coupled systems of nonlinear partial differential equations are solved using multi-dimensional numerical PDEs solvers coupled with PDE-tools in MATLAB. With the aids of the solutions, parametric studies were performed. The results indicate that increasing the downstream angle decreases the stability of the system. Also, the results obtained from the dynamic behaviour of the system

关键词： Branched nanotubes Navier-Stokes equation Numerical methods Transverse and longitudinal vibration

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A comprehensive evaluation of the use of graphene enriched cutting fluids on the surface integrity of very poor-grindability materials

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Wear 2025年 571卷

作者： de Oliveira, Déborah de Paiva, Raphael Lima de Souza Ruzzi, Rodrigo Jackson, Mark James Gelamo, Rogério Valentim Machado, Alisson Rocha da Silva, Rosemar Batista University of Brasília Department of Mechanical Engineering DF Brasília Brazil Federal University of Piauí School of Mechanical Engineering PI Teresina Brazil Federal University of Uberlandia School of Mechanical Engineering MG Uberlandia Brazil Kansas State University College of Technology and Aviation SalinaKS United States Federal University of Triângulo Mineiro Institute of Technological and Exact Sciences MG Uberaba Brazil Pontifícia Universidade Católica do Paraná Mechanical Engineering Graduate Program PR Curitiba Brazil

The use of graphene has stood out in recent years in different fields due to the wide applicability based on its properties. Specifically, multilayer graphene can be highlighted as a good lubricant, it possesses low shear resistance between layers and has good thermal conductivity. Those characteristics are well suitable for cutting fluids, especially considering the grinding process which presents high friction, elastic and plastic deformations, and the intense occurrence of plowing, thereby resulting in high specific cutting energy. However, studies have shown the use of graphene on cutting fluids can be influenced by many factors, including delivery methods, particle concentrations and even the workpiece material. Thus, a comprehension of how graphene particles added to the cutting fluid interact at the abrasive-chip interface is important for its correct use and the achievement of high-quality surfaces. In this sense, this work aims to investigate the use of multilayer graphene enhanced cutting fluids delivered during the grinding process for three different very poor-grindability materials: Inconel 625, Inconel 718 and SAE 52100 hardened steel. Different multilayer graphene concentrations (0.05–0.1 wt%) were added in the same base fluid and tested under different flow rates. The influence of graphene was assessed in terms of grinding power, surface roughness and morphology (SEM images). The experimental results showed that for the lower hardness material (Inconel 625), graphene promoted intense plowing and adhered material on the ground surface, while for the SAE 52100 steel, minor effects were generated on the surface affecting its integrity. For Inconel 718, that possesses both high hardness and ductile responses, the presence of graphene in the cutting fluid provides a great improvement in cutting, resulting in 15 % and 27 % reduction in surface roughness values and grinding power, respectively, even for a low cutting fluid flow rate. © 2025 Elsevier B.V.

关键词： Grinding (machining)

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Cellulose processing using ionic liquids: An analysis of patents and technological trends

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Heliyon 2024年第20期10卷 e39590页

作者： Vieira, Suellen Rocha Silva, Jania Betânia Alves da Pessôa, Luiggi Cavalcanti Nascimento, Renata Quartieri Galván, Karina Lizzeth Pedraza Souza, Carolina Oliveira de Cardoso, Lucas Guimarães Santana, Jamille Santos Assis, Denilson de Jesus Graduate Program in Chemical Engineering (PPEQ) Polytechnic School Federal University of Bahia (UFBA) Bahia Salvador 40210-630 Brazil Center for Exact and Technological Sciences Collegiate of Mechanical Engineering Federal University of Recôncavo of Bahia (UFRB) Bahia Cruz das Almas 44380-000 Brazil Graduate Program in Biotechnology-Northeast Biotechnology Network (RENORBIO) Federal University of Bahia (UFBA) Bahia Salvador 40231-300 Brazil Graduate Program in Food Science (PGAli)–College of Pharmacy Federal University of Bahia (UFBA) Bahia Salvador 40110-100 Brazil Department of Bromatological Analysis College of Pharmacy Federal University of Bahia (UFBA) Bahia Salvador 40110-100 Brazil Department of Engineering University Salvador (UNIFACS) Bahia Salvador 41820-021 Brazil

The production of cellulose derivatives using ionic liquid (IL) as solvents and catalysts has become prominent over the last few years, since the process eliminates the use of toxic substances. This study aimed to map and understand the trends in cellulose processing using ILs by a patent analytic approach and technology life cycle modeling. The documents were searched on the Espacenet® and Orbit® *** majority of innovations have come from companies based in developed countries. The data fitted to the sigmoid BiDoseResp model and the life cycle S-curve showed a market in an early stage of maturity. This mapping brings information that subsidizes decision-making regarding investments, research, and innovations aimed at IL-mediated cellulose treatment. Potential markets mostly use ILs of the imidazolium family in polymer chemistry, machinery, and biotechnology technologies. However, medical and pharmaceutical technologies and microstructure and nanostructure applications are still emerging, fostering perspectives for innovation. © 2024

关键词： Cellulose Dissolution Ionic liquids Mathematical model Patents

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Sensory profile estimation of yacon (Smallanthus sonchifolius) juice acidified with lactobionic acid: Combination of flash profile, E-nose and sensometrics: E-nose and Flash Profile Correlating Sensometrics of Yacon Juice

Food Chemistry Advances

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Food Chemistry Advances 2024年 4卷

作者： Marques, Caroline Toazza, Carlos Eduardo Bortolan Bona, Evandro Mitterer-Daltoé, Marina Leite Masson, Maria Lucia Department of Chemical Engineering Graduate Program in Food Engineering (PPGEAL) Federal University of Paraná Av. Francisco Heráclito dos Santos n. 100 PR Curitiba 81531-980 Brazil Department of Food Engineering Graduate Program in Food Technology (PPGTA) Federal University of Technology-Paraná Via Rosalina Maria dos Santos n. 1233 PR Campo Mourão 87301-899 Brazil Department of Chemistry Graduate Program in Chemical and Biochemical Technology Processes (PPGTP) Federal University of Technology-Paraná Km 01 PR Pato Branco 85503-390 Brazil

Yacon juice is a worthy alternative of a product able to keep all the benefits of the yacon roots. Lactobionic acid has been studied as a food functional acidifier, although still without permission to be applied in foods, cannot be sensory evaluated. Thus, the only approach to estimate a sensory profile of a lactobionic acid-added product is correlating sensory data with chemometric assessments. Sensory evaluation of yacon juice was performed with flash profile and its results were correlated with E-nose ones. Sensometrics showed a high similarity between yacon juice with lactobionic acid and tartaric acid regarding the volatile signals, and both raised the descriptors: Astringency, yellow color pearl-like, herbal, soy, cereal and leaf flavor, acid and bitter residual flavors. This study showed not just the potential of yacon juice as a new product, but also the suitability of combining flash profile and sensometrics to access a potential ingredient. © 2023 The Authors

关键词： Chemometrics Functional food GPA Lactobionic acid Product development

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Correction strategy for wear-out prediction of PV inverters considering the mission profile resolution effects

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Microelectronics Reliability 2022年 135卷

作者： Silva, R.P. de Barros, R.C. Boaventura, W.C. Cupertino, A.F. Pereira, H.A. Department of Electrical Engineering Federal University of Viçosa MG Viçosa Brazil Graduate Program in Electrical Engineering Federal University of Minas Gerais MG Belo Horizonte Brazil Department of Materials Engineering Federal Center for Technological Education of Minas Gerais MG Belo Horizonte Brazil

In literature, there are reliability studies on electrical power systems with several mission profile (MP) resolutions. Although high-resolutions MPs represent more accurately the actual behavior of the system operating conditions, they are more difficult to be correctly recorded and lead to lifetime simulations with high computational burden. In this context, low-resolution MPs are an interesting alternative to solve these issues. However, previous works have concluded that the decreased MP resolution modifies the dynamics of the actual mission profile, which inevitably affects the wear-out prediction accuracy of power converters. Thus, this work proposes a correction strategy to reduce the errors in the lifetime consumption (LC) estimations of a single-phase grid-connected photovoltaic (PV) inverter due to the MP resolution decreasing. Primarily, the strategy aims to determine a correction equation which is able to reduce the deviations in the LC estimations of a PV inverter when MPs with different sampling time values are used in the lifetime evaluation procedure. The results demonstrate that the correction equation determined by the proposed strategy improves the lifetime evaluations for the considered low-resolution MPs. In addition, the determined equation proved to be adaptable to the characteristics of solar irradiance and ambient temperature of different regions of the word. © 2022 Elsevier Ltd

关键词： Forecasting

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Power-based Control for Microgrids and Extreme Fast Charging Stations with Low-Harmonic Current Content in the Medium Voltage Power Grid

Power-based Control for Microgrids and Extreme Fast Charging...

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IEEE Transportation Electrification Conference and Expo (ITEC)

作者： Dener A. De L. Brandão Thiago M. Parreiras João Marcus S. Callegari Igor A. Pires Danilo I. Brandao Braz De J. Cardoso Filho Graduate Program in Electrical Engineering Universidade Federal de Minas Gerais Belo Horizonte MG Brazil Institute of Technological Sciences - Universidade Federal de Itajubá Itabira Minas Gerais Brazil Department of Electronic Engineering Universidade Federal de Minas Gerais Belo Horizonte Brazil Department of Electrical Engineering Universidade Federal de Minas Gerais Belo Horizonte Brazil

The energy and transport sectors are responsible for a large portion of the emission of polluting gases into the atmosphere. Less polluting forms of energy and the electrification of the vehicle fleets are solutions to reduce this emission. In this context, the effect of high penetrion of distributed generation resources (DERs) and extreme fast charging (XFC) stations in the power grid is more evident. This paper proposes the use of the power-based control (PBC) to manage microgrids and XFC stations connected to the medium-voltage (MV) power grid. With the proposed control, the stations can mitigate the effect of the insertion of intermittent sources on the power system. Simulation results show that the active power dispatchability is achieved at the point of common coupling (PCC) with the proposed strategy, smoothing the power demand by 41 %. In such a scenario, the current total demand distortion (TDD) in the XFC stations is 0.19% using the Zero Harmonic Distortion (ZHD) converter.

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Stability analysis of uncertain discrete-time systems with time-varying delays using Difference-Algebraic Representation

Stability analysis of uncertain discrete-time systems with t...

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European Control Conference (ECC)

作者： Má rcia L. C. Peixoto Gabriela L. Reis Pedro H. S. Coutinho Leonardo A. B. Torres Reinaldo M. Palhares Graduate Program in Electrical Engineering Federal University of Minas Gerais Brazil Graduate Program in Electrical Engineering Federal University of Minas Gerais Department of Technological Education Federal Institute of Southeast Minas Gerais Minas Gerais Brazil Department of Aerospace Engineering California Polytechnic State University CA USA Department of Electronics Engineering Federal University of Minas Gerais Minas Gerais Brazil

ISBN: (数字)9783907144077

ISBN: (纸本)9781665497336

This paper addresses the stability analysis of uncertain discrete-time delayed systems described by Difference-Algebraic Representations (DAR). This kind of representation allows dealing with rational functions of the state as well as uncertain parameters. New delay-dependent Linear Matrix Inequalities based-conditions are obtained with a parameter-dependent Lyapunov-Krasovskii functional jointly with the Wirtinger-based summation inequality and the delay-dependent Moon's inequality with a suitable augmented vector. Numerical examples illustrate the potential and effectiveness of the proposed conditions.

关键词： Discrete-time systems Codes Moon Finance Europe Stability analysis Delays

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Water Activated Catechol Adhesive Allows Dip Coated Antimicrobial Coatings

SSRN

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SSRN 2023年

作者： Ghosh, Animesh Singh, Juhi Lim, Sierin Steele, Terry W.J. 639798 Singapore NTU Institute for Health Technologies Interdisciplinary Graduate Program Nanyang Technological University 61 Nanyang Drive 637335 Singapore School of Chemical and Biomedical Engineering Nanyang Technological University 70 Nanyang Drive Block N1.3 637457 Singapore

Bioadhesives comprising of catechol crosslinkers have displayed broad utility against both soft and hard substrates. However, catechol’s two-part adhesion chemistry requires oxidative chemicals that are detrimental to organic substrates. Herein, a water-activated adhesive with inherent antibacterial properties is prepared by grafting catechol groups onto branched polyethylenimine (PEI-DBA20). The resultant PEI-DBA20 is stable in organic solvents but undergoes curing in the presence of water. The in-built oxidation method relies on the close proximity of catechol/Schiff-base functional groups that form tautomers in the presence of aqueous solvents. The curing mechanism is demonstrated by dip coating hydrated substrates, where the grafted dendrimers subsequently crosslink and form thin films. Coated PET films and polyester textiles exhibit an antimicrobial surface with 4-6 log reduction against model Gram-negative bacteria. © 2023, The Authors. All rights reserved.

关键词： Adhesion

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Evaluation of the extraction of antioxidant compounds from buriti pulp (Mauritia flexuosa L.) by response surface methodology

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Heliyon 2025年第2期11卷 e41926页

作者： Nogueira, Gabriela Mota Cardoso, Flávia Aparecida Reitz Perdoncini, Márcia Regina Ferreira Geraldo da Silva, Marcos Vieira Rigobello, Eliane Sloboda Department of Food Engineering and Chemical Engineering Federal University of Technology–Paraná (UTFPR) Campo Mourão 87301-005 Brazil Post-Graduation Program of Food Technology (PPGTA) Federal University of Technology–Paraná (UTFPR) Campo Mourão 87301-005 Brazil Post-Graduation Program of Technological Innovations (PPGIT) Federal University of Technology–Paraná Campo Mourão 87301-005 Brazil Instituto Federal Farroupilha Campus Alegrete Alegrete 97555-000 Brazil

Buriti is a fruit rich in antioxidant compounds, and hydroalcoholic extracts were produced from its pulp to investigate the extraction conditions that result in the highest concentrations of bioactive compounds and maximum antioxidant capacity. The results showed considerable variation in the bioactive compound contents in the pulp: total phenolics (104.64–270.61 mg GAE 100 g-1), total flavonoids (17.74–60.46 mg EC 100 g⁻¹), and total carotenoids (1.30–3.92 mg kg⁻¹). The antioxidant capacity of the extracts, evaluated by DPPH, ABTS, and FRAP methods, ranged from 1.23 to 3.47 μmol ET g⁻¹, 6.34–15.86 μmol ET g⁻¹, and 4.74–11.95 μmol ET g⁻¹, respectively, highlighting the broad diversity of antioxidant activities present in the extracts. Data modeling generated statistically significant mathematical models and contour graphs, which allowed the identification of the optimal extraction conditions for the compounds. Total carotenoids were most effectively extracted with 20 % buriti pulp, intermediate ethanol concentrations, and temperatures around 70 °C. All other bioactive compounds were more efficiently extracted with 5 % buriti pulp, intermediate ethanol concentrations, and temperatures close to 30 °C. The results confirmed the efficiency of the extractions and highlighted the excellent antioxidant potential of buriti pulp. Additionally, the analysis of the optimal regions for extracting antioxidant compounds from the pulp can be applied in future studies to optimize the extraction process, providing a solid foundation for using this fruit in industrial processes, such as the production of functional ingredients. © 2025

关键词： Antioxidants Buriti Experimental design Extraction Pulp

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Predicting lipoabdominoplasty complications with infrared thermography: a delta-R analysis

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Archives of Plastic Surgery 2022年第5期48卷 553-558页

作者： Patricia Rodrigues Resende Marcos Leal Brioschi Franciele De Meneck Eduardo Borba Neves Manoel Jacobsen Teixeira Postgraduate Program in Thermology and Medical Thermography Hospital das Clínicas Faculty of Medicine University of São Paulo São Paulo School of Medicine Federal University of São Paulo São Paulo Graduate Program in Biomedical Engineering Federal Technological University of Paraná Curitiba

The diagnosis of the main complications resulting from lipoabdominoplasty has not yet been standardized. Infrared thermal imaging has been used to assess possible complications, such as necrosis and changes in micro- and macro-circulation, based on perforator mapping techniques, among others. The objective of this study was to present two clinical cases involving thermal imaging monitoring of the healing process of lipoabdominoplasty in the immediate postoperative evaluation and its preliminary results. Infrared thermography was performed 24 hours after the operation and on postoperative days 5, 25, and 27. In clinical case 1, it was found that the delta-R (∆T

关键词： Thermography Abdominoplasty Lipoabdominoplasty Postoperative complications Abdominal wall

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