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Thermal Conductivity-Based Hygrometers
Published in Ghenadii Korotcenkov, Handbook of Humidity Measurement, 2019
Thermal conduction is when thermal energy transfers from one object to another. Physical contact between two bodies is required for the heat conduction. Kinetic energy is transferred to a cooler body from a warmer body by thermally agitating its particles. As a result, the cooler body gains heat while the warmer body loses heat. For instance, a heat passage through a rod is governed by a law similar to Ohm’s law; the heat flow rate is proportional to the thermal gradient across the material (dT/dx) and its cross-sectional area (A), or () H=dQdT=−λ⋅AdTdx
Kiln-Wide Lumber Drying
Published in Vasile Minea, Industrial Heat Pump-Assisted Wood Drying, 2018
Thermal conduction is the mechanism of heat transfer between parts of continuum solids due to the transfer of energy between particles or groups of particles at the atomic level. The Fourier equation expresses steady-state conduction in one dimension from a high to a low temperature through a medium (McQuiston et al. 2005):
Autoclaved aerated concrete
Published in Ash Ahmed, John Sturges, Materials Science in Construction: An Introduction, 2014
Thermal conduction is the phenomenon by which heat is transported from high to low temperature regions of a substance. The property that characterises the ability of a material to transfer heat is the thermal conductivity. It is best defined in terms of the expression:
Heat transfer simulation through textile porous media
Published in The Journal of The Textile Institute, 2023
Elena Codau, Teodor-Cezar Codau, Iuliana-Gabriela Lupu, Aliona Raru, Daniela Farima
Thermal conduction is a mechanism of heat transfer that takes place within a thermodynamic system or between systems with thermal contact. Conduction is due to direct molecular interactions and does not involve a mass transfer. The equations of conduction heat transfer were deduced by Fourier in 1882, based on experimental results. Thus, it was established that the heat flux, ϕ, in any direction, is proportional to the temperature gradient in that direction. The coefficient of proportionality is called thermal conductivity, k, and is a tensor type. For homogeneous and isotropic materials, the thermal conductivity becomes a scalar with a constant value, and the Fourier law can be written as (Rathore, 2015): where: k is thermal conductivity, ρ – density, Cp - thermal capacity, T – temperature, t - time variable and - divergence of gradient temperature (Laplace operator).
Infinite shear rate aspect of the cross-nanofluid over a cylindrical channel with activation energy and inclined magnetic dipole effects
Published in Waves in Random and Complex Media, 2022
Thongchai Botmart, Assad Ayub, Zulqurnain Sabir, Wajaree weera, R. Sadat, Mohamed R. Ali
The purpose of this study is to present the fluid flow at a high or low shear rate, which is characterized by the infinite shear viscosity concept based on the Cross fluid with its infinite shear rate over the geometry of a cylindrical channel. Velocity analysis is made by imposing an inclined magnetic field on cylindrical geometry. A few concluding remarks on this work are presented: The infinite shear aspects of Cross-nanofluid provide the lower velocity.The inclination of the magnetic dipole impacts represents the minimal velocity with high energy.The unsteadiness parameter values are associated with the time factor and the velocity magnitude becomes lower.The Cross-fluid model is provided through the tensor of Cauchy stress along with the PDEs. Similarity transformations have been used to convert the PDEs into ordinary differential equations.The numerical performances of the obtained system have been obtained by using the bvp4c method.The increment of the Brownian parameter reasons to transform the small particles and temperature enhancement.Thermal conduction is directly related to temperature.
Tribological and rheological properties of the lubricant containing hybrid graphene nanosheets (GNs)/titanium dioxide (TiO2) nanoparticles as an additive on calcium grease
Published in Journal of Dispersion Science and Technology, 2022
Bahaa M. Kamel, Enas l. Arafa, Alaa Mohamed
Thermal conduction is the heat transfer from one side of a body to another side. The device used to determine the conductivity of nano grease is a KD2 pro thermal analyzer. This instrument uses the hot wire approach to operate.[32,33] Thermal conductivity is measured according to ASTM D 5334-00.[34] Thermal properties (λ) are given by flowing the formula where q is the amount of heat (W/m2), d distance between two sides (m), T1 and T2 are the temperatures on the heat and colder side (K).