Article
Multidisciplinary Sciences
Miguel Sanches, Guido Marseglia, Ana P. C. Ribeiro, Antonio L. N. Moreira, Ana S. Moita
Summary: This paper investigates the thermal performance of nanofluids in spray cooling applications, focusing on the impact of nanoparticle geometry, concentration, and structure on heat transfer enhancement. The study shows that increasing nanoparticle concentration leads to lower surface temperatures and higher heat fluxes, while also affecting the thermophysical properties of the nanofluids. This research highlights the importance of experimental data in accurately setting model parameters for spray dynamics and heat transfer phenomena.
Article
Thermodynamics
Guido Marseglia, M. Sanches, A. P. C. Ribeiro, A. L. N. Moreira, A. S. Moita
Summary: The current study investigates the parametric characterization of nanofluid sprays to enhance the thermal performance of spray cooling systems. The results show that nanofluids can improve the thermal performance of spray cooling, with the lowest surface temperature obtained with 0.5% alumina nanofluid and the silver nanofluid with spherical particles achieving the lowest surface temperature compared to triangular particles. The heat transfer coefficients decrease with increasing thermal conductivity and dynamic viscosity of the nanofluids, while a positive correlation is found between the specific heat capacity of the nanofluids and the spray cooling capacity.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Gangtao Liang, Han Yang, Jiajun Wang, Shengqiang Shen
Summary: This study assesses the pool boiling critical heat flux (CHF) of nanofluids, demonstrating that the maximum CHF ratio of nanofluid to base fluid can reach 4 and 4.6 for different orientations of heaters. The type of heater (wire or block) has a significant impact on CHF, with direct electric-heating wire heaters accelerating nanoparticle deposition. Pressure and nanoparticle size affect CHF, but dispersion level of particles in base fluid plays a more crucial role in determining CHF ratio.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Chemistry, Multidisciplinary
Wagd Ajeeb, S. M. Sohel Murshed
Summary: This paper presents an experimental investigation on the heat transfer characteristics of new and recycled Alumina nanofluids in a pool boiling system. The study evaluates the performance and reusability of these nanofluids for long-term applications. The results show significant enhancements in critical heat flux and burnout heat flux for the nanofluids, indicating their potential for heat transfer systems.
Article
Energy & Fuels
Vladimir Serdyukov, Ivan Malakhov, Anton Surtaev
Summary: This paper presents the results of an experimental study on the evolution of a nonstationary temperature field during ethanol pool boiling in a pressure range of 12-101.2 kPa. Experimental data obtained using infrared thermography reveal the significant impact of pressure reduction on heat transfer rate near the vapor bubbles. Microlayer evaporation removes a significant heat flux density from the heating surface, which exceeds the input heat power by a factor of 3.3-27.7, with the heat transfer rate in the microlayer area decreasing as pressure decreases.
Article
Energy & Fuels
Ricardo Santos, Ana Sofia Moita, Ana Paula C. Ribeiro, Antonio Luis N. Moreira
Summary: This study investigates the impact of alumina nanoparticle nanofluids on pool boiling performance and analyzes the possible effects of nanoparticles on boiling and heat transfer mechanisms. The optimal nanoparticle concentration was found to be 3 wt%, which significantly enhances heat transfer coefficients.
Article
Biochemistry & Molecular Biology
Thong Le Ba, Ahmed Baqer, Mohammed Saad Kamel, Gyula Grof, Vincent Otieno Odhiambo, Somchai Wongwises, Lezsovits Ferenc, Imre Miklos Szilagyi
Summary: This study aims to experimentally investigate the pool boiling heat transfer performance of novel Halloysite nanofluids under atmospheric pressure condition, and analyze the relationship between the volume concentration of nanofluids and the heat transfer coefficient.
Article
Thermodynamics
Yong Il Kim, Keunhee Jang, Chanwoo Park, Seongpil An, Alexander L. Yarin, Sam S. Yoon
Summary: A swing-like heater was designed and studied for cooling high-power microelectronic devices under pool boiling conditions. The swing motion improved the cooling effectiveness of the heater, shedding vapor-bubble cloud and enhancing heat removal. This method could be used not only under normal gravity on Earth, but also in microgravity conditions during space exploration.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Chemical
Xu Ma, Yindong Song, Yang Wang, Shouguang Yao, Kambiz Vafai
Summary: In this study, novel hybrid nanoparticles were prepared using Ag modified functionalized GNP, and the boiling heat transfer properties of the nanofluids were investigated. The GNP-Ag hybrid nanofluids with a weight concentration of 0.001% exhibited the best heat transfer performance, with improved structural modification and wetting properties playing a crucial role in enhancing the heat transfer.
Article
Thermodynamics
Pravin O. Sharma, Surendra D. Barewar, Sandesh S. Chougule
Summary: The study investigated the enhancements in thermal properties, CHF, and HTC of novel Ag/ZnO hybrid nanofluid at various concentrations. It was found that within a certain concentration range, the nanofluid can enhance heat transfer, but exceeding a certain concentration can deteriorate the boiling heat transfer.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Chemistry, Analytical
Kairui Tang, Jingjing Bai, Siyu Chen, Shiwei Zhang, Jie Li, Yalong Sun, Gong Chen
Summary: This study developed multilayer copper micromeshes for commercial compact electronic cooling and investigated their boiling heat transfer performance. The MCM-5 showed the highest critical heat flux and heat transfer coefficient due to its abundant micropores serving as nucleate sites and outstanding capillary wicking capability. The micromeshes were also found to perform competitively with other surface structures in high-power cooling applications.
Article
Thermodynamics
Matic Moze, Armin Hadzic, Matevz Zupancic, Iztok Golobic
Summary: Surface engineering is an effective approach to improve the nucleate boiling process by tuning the wettability and morphology of the boiling surface. In this study, TiO2 nanostructures were fabricated on titanium foils, and the effects of hydrophobic surface treatment on nucleate boiling were investigated. The results show that hydrophobic surfaces increase the nucleation site density and bubble frequency, reduce the bubble nucleation temperature, and significantly enhance the heat transfer coefficient.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Chemistry, Multidisciplinary
Wagd Ajeeb, S. M. Sohel Murshed
Summary: This study investigates the pool boiling heat transfer performance of hybrid and mono nanofluids containing boron nitride and silicon dioxide nanoparticles. The results show that both types of nanofluids demonstrate improvements in critical heat flux and burnout heat flux compared to the base fluid, with the highest enhancement observed in a boron nitride-based mono nanofluid.
Review
Thermodynamics
Khudir Z. Zarrag, Firas B. Ismail, Tan E. Sann, Laith J. Habeeb
Summary: The purpose of this article is to examine the current state of nucleate pool boiling heat transfer in various fluids. Different aspects of heat transfer in pool boiling are discussed, such as pool boiling of nanofluids, boiling behavior of water-glycerin combinations, and operational parameters. By using appropriate mixes of hydrocarbons and other commercial liquids, higher heat transfer coefficients can be achieved. Coatings of nanoparticles on the heater surface can be optimized to improve heat transfer from the pool to the surrounding water. The addition of nanofluids or surface coatings can enhance pool boiling critical heat flux.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART A-JOURNAL OF POWER AND ENERGY
(2023)
Article
Chemistry, Physical
Ashutosh Pare, Subrata Kumar Ghosh
Summary: The study focuses on the surface-associated qualitative analysis of the nucleate pool boiling heat transfer characteristics of alumina-water based nanofluids. Experimental results were used to develop an optimal artificial neural network (ANN) design with various training algorithms and hidden layers. The nanofluids were prepared using alumina nanoparticles and distilled water, with varying concentrations and were characterized using various techniques such as FESEM, EDAX, zeta potential stability test, and thermophysical analysis. The study found that nanofluids demonstrated up to a 70% enhancement in pool boiling heat transfer compared to distilled water, and the ANN model using the Levenberg Marquardt algorithm exhibited the most optimized structure.
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
(2021)
Article
Materials Science, Composites
Ana Paulo, Jorge Santos, Joao da Rocha, Rui Lima, Joao Ribeiro
Summary: The authors developed PLA composites reinforced with flax fibers to evaluate the improvement of tensile and flexural strength. It was found that the surface chemical treatment of the fiber did not have any influence on the mechanical properties of the composites, while the infill density had a huge influence on the improvement of mechanical strength. The maximum values of tensile and bending stress were 50 MPa and 73 MPa, respectively. Natural fiber reinforcement can improve the mechanical properties of PLA composites.
JOURNAL OF COMPOSITES SCIENCE
(2023)
Review
Energy & Fuels
Jose Pereira, Ana Moita, Antonio Moreira
Summary: The research in the field of nanofluids, suspensions of nano-sized solid particles in thermal fluids, has advanced significantly in the past twenty years. While water-based nanofluids with improved thermal conductivity have been extensively studied, a novel class of nanofluids based on inorganic salts has emerged for high-temperature thermal energy storage and transfer. The inclusion of nanoparticles in molten salt-based nanofluids generally enhances specific heat, but this property is influenced by various factors that will be thoroughly discussed. This review aims to provide a comprehensive survey of published scientific articles on molten salt nanofluids and explore their development, thermal behavior, and potential applications in concentrated solar power technology.
Article
Energy & Fuels
Jessica Martha Nunes, Jeferson Diehl de Oliveira, Jacqueline Biancon Copetti, Sameer Sheshrao Gajghate, Utsab Banerjee, Sushanta K. Mitra, Elaine Maria Cardoso
Summary: This study analyzes the influence of different heights of square micro pin fins on pressure drop and heat transfer behavior. The results show that the highest micro pin fins configuration provides a more uniform and lowest wall temperature distribution compared to the lowest configuration. Experimental results for two-phase flow condition demonstrate that an increase in mass flux enhances heat transfer for low heat flux, with boiling heat transfer becoming more predominant as heat flux increases. The pressure drop drastically increases with the vapor amount flowing into the system, regardless of the pin fin height.
Editorial Material
Chemistry, Analytical
Luis Goncalves, Marcos Silva Martins, Rui A. Lima, Graca Minas
Article
Chemistry, Multidisciplinary
Ana Rita F. Pacheco, Beatriz D. Cardoso, Ana Pires, Andre M. Pereira, Joao P. Araujo, Violeta M. Carvalho, Raquel O. Rodrigues, Paulo J. G. Coutinho, Teresa Castelo-Grande, Paulo A. Augusto, Domingos Barbosa, Rui A. Lima, Senhorinha F. C. F. Teixeira, Ana Rita O. Rodrigues, Elisabete M. S. Castanheira
Summary: Late diagnosis and systemic toxicity associated with conventional treatments pose challenges in cancer therapy. Nanomedicine offers a new approach for prevention, diagnosis, and treatment of cancer. This study developed pH-sensitive solid magnetoliposomes (SMLs) for controlled release of the chemotherapeutic drug doxorubicin (DOX). The SMLs showed efficient drug release at pH = 5 and significantly reduced cell viability when exposed to tumor cells, suggesting their potential for synergistic cancer therapy with magnetic targeting and dual hyperthermia.
Review
Pharmacology & Pharmacy
Renata Maia, Violeta Carvalho, Rui Lima, Graca Minas, Raquel O. Rodrigues
Summary: This systematic review summarizes the recent progress in the use of microneedles (MNs) in biomedical applications, including drug delivery, biomarker detection, and their potential integration with microfluidic devices. Although MNs have been extensively utilized in lab-on-a-chip platforms, recent studies have also explored their applicability in organ-on-a-chip models. Overall, the presence of MNs in advanced microfluidic devices offers simplified drug delivery, microinjection, and biomarker detection through integrated biosensors, enabling real-time monitoring of various biomarkers in lab- and organ-on-a-chip platforms.
Review
Engineering, Mechanical
Ines S. Afonso, Glauco Nobrega, Rui Lima, Jose R. Gomes, Joao E. Ribeiro
Summary: Vegetable oils have long been used as metalworking fluids, especially in smaller operations and industries with strict environmental regulations. They can be enhanced with additives or nanoparticles to improve lubricity, cooling properties, and stability. Compared to standard MWFs, vegetable oils are more environmentally friendly and cost-effective. However, the choice of MWFs depends on specific requirements and the balance between performance, cost, and environmental considerations.
Article
Biochemistry & Molecular Biology
Pedro M. G. Silva, Pedro F. F. Pinheiro, Sergio P. Camoes, Ana P. C. Ribeiro, Luisa M. D. R. S. Martins, Joana P. G. Miranda, Goncalo C. Justino
Summary: The growing worldwide cancer incidence and multidrug cancer resistance require the identification of new leads for cancer management. This study investigated two C-scorpionate complexes as potential scaffolds for anticancer drug development, with one complex showing significant cytotoxicity and cell migration inhibitory activity against HCT116 cells.
Review
Biochemistry & Molecular Biology
Jose Pereira, Ana Moita, Antonio Moreira
Summary: This review critically surveys the published studies on nano-enhanced phase change materials for energy harvesting and conversion, discussing their thermophysical characteristics and analyzing their properties such as phase change duration and temperature. Various techniques for improving phase change materials for solar thermal applications are described, including the use of nanoparticles, foam skeleton reinforcement, and phase change materials with extended surfaces. These techniques can significantly increase the thermal conductivity of the systems. The exploration of phase change materials enhances the efficiency of solar thermal energy storage and photovoltaic-nano-enhanced phase change materials.
Article
Thermodynamics
R. R. Souza, F. M. Sa Barbosa, G. Nobrega, E. M. Cardoso, J. C. F. Teixeira, A. S. Moita, R. Lima
Summary: This article presents the development stages of a serpentine heat exchanger made of a thin layer of a silicon-based organic elastomeric polymer (PDMS). This heat exchanger allows the liquid to directly wet the cooling surface, which is an innovation compared to traditional exchangers. Experimental results showed that despite its low thermal conductivity, PDMS has a greater cooling capacity, reducing the surface's temperature by an average of 17%.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
R. R. Souza, F. M. Sa Barbosa, G. Nobrega, E. M. Cardoso, J. C. F. Teixeira, A. S. Moita, R. Lima
Summary: Traditional methods do not allow investigation of critical features that affect the heat transfer performance of nanofluids, therefore an innovative method is needed to measure their thermal conductivity.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Chemistry, Physical
Girolamo Casella, Silvia Carlotto, Ana P. C. Ribeiro, Luisa M. D. R. S. Martins
Summary: We used DFT methods to investigate the reaction mechanism of the Radzisewski reaction for obtaining an amide from ACN and H2O2. The direct reaction between ACN and H2O2 showed high activation energy, making it unreliable. Instead, a fast reaction between ACN and HOO- forming the deprotonated species of PAIA was observed. Our findings reconciled the discrepancy in the assignment of the rate determining step by considering the regioselective path for obtaining the required configuration to form the amide.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Thermodynamics
G. Marseglia, M. G. De Giorgi, P. Pontes, R. Solipa, R. R. Souza, A. L. N. Moreira, A. S. Moita
Summary: This paper investigates the advantages and challenges of two-phase flows, specifically flow boiling of pure liquids and nanofluids, for cooling microchannel heat sinks. The study finds that even at low concentrations, the water-Au nanofluid exhibits superior cooling performance compared to other fluids, indicating that even small concentrations of nanoparticles can significantly impact heat transfer mechanisms.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Proceedings Paper
Computer Science, Interdisciplinary Applications
Violeta Carvalho, Nelson Rodrigues, Jose C. Teixeira, Rui Lima, Senhorinha Teixeira
Summary: Atherosclerotic cardiovascular disease, a common pathology that affects millions of people, has been extensively studied using experimental and numerical research methods. This study compares different models for simulating blood flow in stenotic coronary arteries and finds that the generation of recirculation zones is intensified in one model, but velocity differences are not significant. Understanding the complex nature of blood and accurately modeling its flow is crucial for advancing research in atherosclerosis.
COMPUTER METHODS, IMAGING AND VISUALIZATION IN BIOMECHANICS AND BIOMEDICAL ENGINEERING II
(2023)