Thermal conductivity of heavy water at high pressures and its dependence on density

1989 ◽  
Vol 56 (4) ◽  
pp. 416-419
Author(s):  
U. B. Magomedov
Keyword(s):  
Thermal Conductivity ◽  
Heavy Water ◽  
High Pressures

scholarly journals The thermal conductivity of the Earth's core and implications for its thermal and compositional evolution

2020 ◽  
Author(s):  
Kenji Ohta ◽  
Kei Hirose
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Thermal History ◽  
Diamond Anvil Cell ◽  
High Pressures ◽  
Iron Alloys ◽  
Compositional Evolution ◽  
The Earth ◽  
Diamond Anvil ◽  
High Pressures And Temperatures

Abstract Precise determinations of the thermal conductivity of iron alloys at high pressures and temperatures are essential for understanding the thermal history and dynamics of the metallic cores of the Earth. We review relevant high-pressure experiments using a diamond-anvil cell and discuss implications of high core conductivity for its thermal and compositional evolution.

scholarly journals Determination of heavy water by means of a thermal conductivity method

1958 ◽  
Vol 7 (5) ◽  
pp. 301-304 ◽  
Author(s):  
Saburo YANAGISAWA ◽  
Michiharu SEKI ◽  
Yoshikazu WATANABE ◽  
Shigeru NAKAMURA ◽  
Fumio MORIYA
Keyword(s):  
Thermal Conductivity ◽  
Heavy Water ◽  
Conductivity Method

ChemInform Abstract: VISCOSITY OF HEAVY WATER AT HIGH PRESSURES

1978 ◽  
Vol 9 (16) ◽  
Author(s):  
H. KINOSHITA ◽  
S. ABE ◽  
A. NAGASHIMA
Keyword(s):  
Heavy Water ◽  
High Pressures

Adiabatic Heat Flow in Mercury with a Fe-8.5wt%Si Core

2021 ◽  
Author(s):  
Meryem Berrada ◽  
Richard Secco ◽  
Wenjun Yong
Keyword(s):  
Thermal Conductivity ◽  
Heat Flow ◽  
Internal Structure ◽  
High Pressures ◽  
Inner Core ◽  
Thermal Evolution ◽  
The Core ◽  
Thermally Driven ◽  
Wire Method ◽  
Core Conditions

<p>Recent theoretical studies have tried to constrain Mercury’s internal structure and composition using thermal evolution models. The presence of a thermally stratified layer of Fe-S at the top of an Fe-Si core has been suggested, which implies a sub-adiabatic heat flow on the core side of the CMB. In this work, the adiabatic heat flow at the top of the core was estimated using the electronic component of thermal conductivity (k<sub>el</sub>), a lower bound for thermal conductivity. Direct measurements of electrical resistivity (ρ) of Fe-8.5wt%Si at core conditions can be related to k<sub>el</sub> using the Wiedemann-Franz law. Measurements were carried out in a 3000 ton multi-anvil press using a 4-wire method. The integrity of the samples at high pressures and temperatures was confirmed with electron-microprobe analysis of quenched samples at various conditions. Unexpected behaviour at low temperatures between 6-8 GPa may indicate an undocumented phase transition. Measurements of ρ at melting seem to remain constant at 127 µΩ·cm from 10-24 GPa, on both the solid and liquid side of the melting boundary. The adiabatic heat flow at the core side of Mercury’s core-mantle boundary is estimated between 21.8-29.5 mWm<sup>-2</sup>, considerably higher than most models of an Fe-S or Fe-Si core yet similar to models of an Fe core. Comparing these results with thermal evolution models suggests that Mercury’s dynamo remained thermally driven up to 0.08-0.22 Gyr, at which point the core became sub-adiabatic and stimulated a change from dominant thermal convection to dominant chemical convection arising from the growth of an inner core. Simply considering the internal structure of Mercury, these results support the capture of Mercury into a 3:2 resonance orbit during the thermally driven era of the dynamo.</p>

Equation of state and thermal conductivity of gases at high pressures and elevated temperatures

1956 ◽  
Vol 22 ◽  
pp. 64 ◽  
Author(s):  
J. Saurel ◽  
R. Bergeon ◽  
P. Johannin ◽  
J. Dapoigny ◽  
J. Kieffer ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Equation Of State ◽  
High Pressures ◽  
Elevated Temperatures

scholarly journals Elastomer Characterization Method for Trapped Rubber Processing

Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 686 ◽  
Author(s):  
Pooria Khalili ◽  
Thomas Boulanger ◽  
Brina J. Blinzler
Keyword(s):  
Thermal Conductivity ◽  
Polymer Matrix ◽  
High Pressures ◽  
Polymer Matrix Composites ◽  
Dynamic Change ◽  
Experimental Tests ◽  
High Volume ◽  
Virtual Design ◽  
Closed Cavity ◽  
Recent Advances

The increasing high-volume demand for polymer matrix composites (PMCs) brings into focus the need for autoclave alternative processing. Trapped rubber processing (TRP) of PMCs is a method capable of achieving high pressures during polymer matrix composite processing by utilizing thermally induced volume change of a nearly incompressible material inside a closed cavity mold. Recent advances in rubber materials and computational technology have made this processing technique more attractive. Elastomers can be doped with nanoparticles to increase thermal conductivity and this can be further tailored for local variations in thermal conductivity for TRP. In addition, recent advances in computer processing allow for simulation of coupled thermomechanical processes for full part modeling. This study presents a method of experimentally characterizing prospective rubber materials. The experiments are designed to characterize the dynamic in situ change in temperature, the dynamic change in volume, and the resulting real-time change in surface pressure. The material characterization is specifically designed to minimize the number and difficulty of experimental tests while fully capturing the rubber behavior for the TRP scenario. The experimental characterization was developed to provide the necessary data for accurate thermomechanical material models of nearly incompressible elastomeric polymers for use in TRP virtual design and optimization.

scholarly journals Relationship between the Transport Coefficients of Polar Substances and Entropy

Entropy ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 13
Author(s):  
Ivan Anashkin ◽  
Sergey Dyakonov ◽  
German Dyakonov
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Diffusion Coefficient ◽  
High Pressures ◽  
Thermal Conductivity Coefficient ◽  
Good Description ◽  
Transport Coefficients ◽  
Viscosity Coefficient ◽  
Wide Region ◽  
Good Agreement

An expression is proposed that relates the transport properties of polar substances (diffusion coefficient, viscosity coefficient, and thermal conductivity coefficient) with entropy. To calculate the entropy, an equation of state with a good description of the properties in a wide region of the state is used. Comparison of calculations based on the proposed expressions with experimental data showed good agreement. A deviation exceeding 20% is observed only in the region near the critical point as well as at high pressures.

The Thermal Conductivity of Earth's Core: A Key Geophysical Parameter's Constraints and Uncertainties

2018 ◽  
Vol 46 (1) ◽  
pp. 47-66 ◽  
Author(s):  
Q. Williams
Keyword(s):  
Thermal Conductivity ◽  
High Pressures ◽  
Inner Core ◽  
Thermal Evolution ◽  
Magnetic Moments ◽  
Earth’S Core ◽  
Earth's Core ◽  
Current State ◽  
Core Conditions

The thermal conductivity of iron alloys at high pressures and temperatures is a critical parameter in governing ( a) the present-day heat flow out of Earth's core, ( b) the inferred age of Earth's inner core, and ( c) the thermal evolution of Earth's core and lowermost mantle. It is, however, one of the least well-constrained important geophysical parameters, with current estimates for end-member iron under core-mantle boundary conditions varying by about a factor of 6. Here, the current state of calculations, measurements, and inferences that constrain thermal conductivity at core conditions are reviewed. The applicability of the Wiedemann-Franz law, commonly used to convert electrical resistivity data to thermal conductivity data, is probed: Here, whether the constant of proportionality, the Lorenz number, is constant at extreme conditions is of vital importance. Electron-electron inelastic scattering and increases in Fermi-liquid-like behavior may cause uncertainties in thermal conductivities derived from both first-principles-associated calculations and electrical conductivity measurements. Additional uncertainties include the role of alloying constituents and local magnetic moments of iron in modulating the thermal conductivity. Thus, uncertainties in thermal conductivity remain pervasive, and hence a broad range of core heat flows and inner core ages appear to remain plausible.

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