Nanofluids obtained from halloysite and de-ionized water (DI) were prepared by using surfactants and changing pH for heat-transfer applications. The halloysite nanotubes (HNTs) nanofluids were studied for several volume fractions (0.5, 1.0, and 1.5 vol%) and temperatures (20, 30, 40, 50, and 60 °C). The properties of HNTs were studied with a scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDX), Fourier-transform infrared (FT-IR) spectroscopy, X-ray powder diffraction (XRD), Raman spectroscopy and thermogravimetry/differential thermal analysis (TG/DTA). The stability of the nanofluids was proven by zeta potentials measurements and visual observation. With surfactants, the HNT nanofluids had the highest thermal conductivity increment of 18.30% for 1.5 vol% concentration in comparison with the base fluid. The thermal conductivity enhancement of nanofluids containing surfactant was slightly higher than nanofluids with pH = 12. The prepared nanofluids were Newtonian. The viscosity enhancements of the nanofluid were 11% and 12.8% at 30 °C for 0.5% volume concentration with surfactants and at pH = 12, respectively. Empirical correlations of viscosity and thermal conductivity for these nanofluids were proposed for practical applications.
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http://dx.doi.org/10.3390/nano10091834 | DOI Listing |
Materials (Basel)
January 2025
Department of Mechanical Engineering, Samsun University, 55420 Samsun, Turkey.
This study addresses the thermal management challenge in battery systems by enhancing phase change material composites with Ni-P and Ni-P-Cu coatings on phase change material/expanded graphite structures. Traditional phase change materials are limited by low thermal conductivity and mechanical stability, which restricts their effectiveness in high-demand applications. Unlike previous studies, this work integrates Ni-P and Ni-P-Cu coatings to significantly improve both the thermal conductivity and mechanical strength of phase change material/expanded graphite composites, filling a crucial gap in battery thermal management solutions.
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January 2025
Department of Materials Science, Tokai University, Hiratsuka 259-1292, Kanagawa, Japan.
Semiconducting single-walled carbon nanotubes (SWCNTs) are significantly attractive for thermoelectric generators (TEGs), which convert thermal energy into electricity via the Seebeck effect. This is because the characteristics of semiconducting SWCNTs are perfectly suited for TEGs as self-contained power sources for sensors on the Internet of Things (IoT). However, the thermoelectric performances of the SWCNTs should be further improved by using the power sources.
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January 2025
School of Civil Engineering, Central South University, Changsha 410075, China.
Small-section steel-shell concrete immersed tube tunnels are intended for minibuses and have a low fire heat release rate. Standard fire rise curves do not apply to such tunnels. In this study, a coupled method of computational fluid dynamics (CFD) and the finite element method (FEM) was used to simulate the structural temperature distribution in tunnels.
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January 2025
State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, China.
Silicon carbide-based titanium silicon carbide (SiC-TiSiC) composites with low free alloy content and varying TiSiC contents are fabricated by two-step reactive melt infiltration (RMI) thorough complete reactions between carbon and TiSi alloy in SiC-C preforms obtained. The densities of SiC-C preform are tailored by the carbon morphology and volumetric shrinkage of slurry during the gel-casting process, and pure composites with variable TiSiC volume contents are successfully fabricated with different carbon contents of the preforms. Due to the increased TiSiC content in the obtained composites, both electrical conductivity and electromagnetic interference (EMI) shielding effectiveness improved progressively, while skin depth exhibited decreased consistently.
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December 2024
Department of Mechanical Engineering, Informatics and Chemistry of Polymer Materials, Faculty of Material Technologies and Textile Design, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland.
This study proposes a two-scale approach to determining the effective thermal conductivity of fibrous composite materials. The analysis was first carried out at the fiber-interphase level to calculate the effective thermal conductivity of this system, and next at the whole composite structure level. At both scales, the system behavior was analyzed using the finite element method.
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