Explaining the “anomalous” transient hot wire-based thermal conductivity measurements near solid-liquid phase change in terms of solid-solid transition

Hoque, Md Shafkat Bin; Ansari, Naseem; Khodadadi, J. M.

doi:10.1016/j.ijheatmasstransfer.2018.04.014

Cited by 11 publications

(5 citation statements)

References 21 publications

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“…When the cold finger is set at 10 °C, the layer has more RC phase present (40%) to the detriment of the rotator phases (45% of the R2 phase and 15% of the R1 phase). These results are in line with what was found by Nabil and Khodadadi 46 and Hoque et al 47 They studied the thermal conductivity of pure eicosane just before and during its melting using the transient hot-wire method. They observed a sudden increase in the thermal conductivity of the alkane just before the melting process.…”

Section: Resultssupporting

confidence: 91%

“…They observed a sudden increase in the thermal conductivity of the alkane just before the melting process. It was hypothesized by Hoque et al based on their evidence that the rearrangement of the solid-state hydrocarbon chain packing during the solid–solid phase transition is what causes the increased thermal conductivity. We propose another hypothesis that the conductivity of the RC lattice is lower than that of the rotator phases.…”

Section: Resultsmentioning

confidence: 99%

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In Situ Thermal Conductivity of a Paraffinic Phase Change Material in a Cold Finger Configuration

Costa,

Pantoja,

Mota

et al. 2023

Crystal Growth & Design

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Phase change materials (PCMs) such as paraffins are widely applied to store thermal energy. PCMs displaying high thermal conductivities are desirable because they crystallize or melt rapidly when the temperature in the environment changes, absorbing or releasing latent heat accordingly. In this work, we experimentally determined the thermal conductivity of PCM layers in situ. To this end, layers that mimic macro-encapsulated PCM devices have been grown in a cold finger experimental setup. The thermal conductivity was determined as the adjustable parameter of a detailed 1D mathematical model for the process of phase change. It has been shown that the thermal conductivity of paraffin increases by as much as 40% to a value of 0.30 W m −1 K −1 when the rate of crystal growth increases from 0.06 to 0.19 kg m −2 s −1 . Furthermore, evidence shows that paraffinic rotator phases cause an increase in the thermal conductivity during the crystallization of the PCM. With the aid of a 2D computational fluid dynamics mathematical model, it has been shown that the heat transfer by natural convection in the molten paraffin was responsible for the noncylindrical shape of the paraffin layer. It is concluded that the crystallization rate should be considered for designing PCM devices with a faster thermal response.

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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

In Situ Thermal Conductivity of a Paraffinic Phase Change Material in a Cold Finger Configuration

Costa,

Pantoja,

Mota

et al. 2023

Crystal Growth & Design

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“…Room temperature and temperature-dependent thermal conductivities of BFO and BHFO nanostructured sintered pellets measured by a hot disk utilizing the transient plane source technique 26,27 are listed in Table 1 and depicted in Figure 6d. The measured room temperature thermal conductivity of BFO varies from 0.19 ± 0.04 to 0.38 ± 0.06 W m −1 K −1 depending on the density of the sintered pellets, indicating that the measured values are significantly lower compared to the literature values (0.78−3.5 W m −1 K −1 ).…”

Section: Resultsmentioning

confidence: 99%

“…All data acquisition and heat capacity estimation were carried out with Proteus software within ∼2% uncertainty. Thermal conductivity was measured by a hot disk utilizing the transient plane source technique. , The pellets of 1.11 cm diameter and 0.24 cm thickness were prepared from the xerogel powder by pressing at two different pressures 2 and 5 tons. The hot disk setup was calibrated with two standard samplesstainless steel (13.7 ± 1.1 W m –1 K –1 ) and BK7 window glass (1.04 ± 0.07 W m –1 K –1 ) .…”

Section: Experimental Sectionmentioning

confidence: 99%

Vacancy-Induced Temperature-Dependent Thermal and Magnetic Properties of Holmium-Substituted Bismuth Ferrite Nanoparticle Compacts

Islam

Zubair

Galib

et al. 2022

ACS Appl. Mater. Interfaces

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Multiferroics have gained widespread acceptance for room-temperature applications such as in spintronics, ferroelectric random access memory, and transistors because of their intrinsic magnetic and ferroelectric coupling. However, a comprehensive study, establishing a correlation between the magnetic and thermal transport properties of multiferroics, is still missing from the literature. To fill the void, this work reports the temperature-dependent thermal and magnetic properties of holmium-substituted bismuth ferrite (BiFeO 3 ) and their dependencies on oxygen vacancies and structural modifications. Two distinct magnetic transitions on temperature-dependent magnetic and heat capacity responses are identified. Experimental analysis suggests that the excess of oxygen vacancies shifts the magnetic transition temperature by ∼64 K. The holmium substitution-induced structural modification increases BiFeO 3 heat capacity by 30% up to the antiferromagnetic phase transition temperature. Furthermore, an unsaturated heat capacity even at temperatures as high as 850 K is observed and is ascribed to anharmonicity and partial densification of the nanoparticles used during heat capacity measurements. The room-temperature thermal conductivity of BiFeO 3 is ∼0.33 ± 0.11 W m −1 K −1 and remains unchanged at high temperatures due to defect scattering from porosities.

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“…Fatigue life data obtained are usually scattered because of the anisotropic and heterogenetic structure of the FRPCs, and therefore, conventional S-N curve is not appropriate to accurately describe and predict fatigue life of FRPCs. [29][30][31][32] Among various statistical methods such as the exponent distribution, normal distribution, lognormal distribution and Crow-AMSAA analysis, two parameter Weibull distribution function has been most widely used for failure analysis of materials. 30,33,34 Weibull distribution is a established model for fatigue life analysis of laminated composites because it can reasonably model wide range of distributed data, provide more information about fatigue life including failure probability and failure mode.…”

Section: Introductionmentioning

confidence: 99%

Flexural fatigue and fracture toughness behavior of nanoclay reinforced carbon fiber epoxy composites

Tareq¹,

Zainuddin

Hosur

et al. 2020

Journal of Composite Materials

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3-point flexural fatigue and Mode I interlaminar fracture tests were done to study the fatigue life and fracture toughness of nanoclay added carbon fiber epoxy composites. Fatigue life data was analyzed using Weibull distribution function, validated with Kolmogorov-Smirnov goodness-of-fit, and predicted by combined Weibull and Sigmoidal models, respectively. The nanophased samples showed more than 300% improvement in mean and predicted fatigue life. At 0.7 stress level, the nanophased samples passed the ‘run-out’ fatigue criteria (106 cycles), whereas, the neat samples failed much earlier. The interlaminar fracture toughness of nanophased samples was also enhanced significantly by 71% over neat samples. Optical and scanning electron microscopic images of the nanophased fractured samples revealed certain features that improved the respective fatigue and fracture properties of the composites.

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Explaining the “anomalous” transient hot wire-based thermal conductivity measurements near solid-liquid phase change in terms of solid-solid transition

Cited by 11 publications

References 21 publications

In Situ Thermal Conductivity of a Paraffinic Phase Change Material in a Cold Finger Configuration

In Situ Thermal Conductivity of a Paraffinic Phase Change Material in a Cold Finger Configuration

Vacancy-Induced Temperature-Dependent Thermal and Magnetic Properties of Holmium-Substituted Bismuth Ferrite Nanoparticle Compacts

Flexural fatigue and fracture toughness behavior of nanoclay reinforced carbon fiber epoxy composites

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