scholarly journals The Viscosities of Partially Molten Materials Undergoing Diffusion Creep

2018 ◽  
Vol 123 (12) ◽  
pp. 10,534-10,562 ◽  
Author(s):  
John F. Rudge
Keyword(s):  
Diffusion Creep ◽  
Molten Materials

scholarly journals Multi-Camera Based Setup for Geometrical Measurement of Free-Falling Molten Glass Gob

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1041
Author(s):  
Mazhar Hussain ◽  
Mattias O’Nils ◽  
Jan Lundgren
Keyword(s):  
Free Fall ◽  
Frame Rate ◽  
Geometrical Parameters ◽  
Contactless Method ◽  
Molten Material ◽  
Dynamic Changes ◽  
Direct Measurements ◽  
Molten Materials ◽  
Free Falling

High temperatures complicate the direct measurements needed for continuous characterization of the properties of molten materials such as glass. However, the assumption that geometrical changes when the molten material is in free-fall can be correlated with material characteristics such as viscosity opens the door to a highly accurate contactless method characterizing small dynamic changes. This paper proposes multi-camera setup to achieve accuracy close to the segmentation error associated with the resolution of the images. The experimental setup presented shows that the geometrical parameters can be characterized dynamically through the whole free-fall process at a frame rate of 600 frames per second. The results achieved show the proposed multi-camera setup is suitable for estimating the length of free-falling molten objects.

scholarly journals A Study of the Impact of Graphite on the Kinetics of SPS in Nano- and Submicron WC-10%Co Powder Compositions

Ceramics ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 331-363
Author(s):  
Eugeniy Lantcev ◽  
Aleksey Nokhrin ◽  
Nataliya Malekhonova ◽  
Maksim Boldin ◽  
Vladimir Chuvil'deev ◽  
...  
Keyword(s):  
Activation Energy ◽  
Solid Phase ◽  
Continuous Heating ◽  
Diffusion Creep ◽  
Hard Alloys ◽  
Fine Grained ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
The Impact ◽  
Kinetics Of

This study investigates the impact of carbon on the kinetics of the spark plasma sintering (SPS) of nano- and submicron powders WC-10wt.%Co. Carbon, in the form of graphite, was introduced into powders by mixing. The activation energy of solid-phase sintering was determined for the conditions of isothermal and continuous heating. It has been demonstrated that increasing the carbon content leads to a decrease in the fraction of η-phase particles and a shift of the shrinkage curve towards lower heating temperatures. It has been established that increasing the graphite content in nano- and submicron powders has no significant effect on the SPS activation energy for “mid-range” heating temperatures, QS(I). The value of QS(I) is close to the activation energy of grain-boundary diffusion in cobalt. It has been demonstrated that increasing the content of graphite leads to a significant decrease in the SPS activation energy, QS(II), for “higher-range” heating temperatures due to lower concentration of tungsten atoms in cobalt-based γ-phase. It has been established that the sintering kinetics of fine-grained WC-Co hard alloys is limited by the intensity of diffusion creep of cobalt (Coble creep).

scholarly journals Development of EXAFS Apparatus for in-situ Measurement of High-Temperature Molten Materials.

1993 ◽  
Vol 32 (6) ◽  
pp. 444-446
Author(s):  
Kazuhiko Omote ◽  
Atsunori Kiku ◽  
Manabu Funahashi ◽  
Kazuyuki Tohji ◽  
Yoshio Waseda
Keyword(s):  
High Temperature ◽  
In Situ Measurement ◽  
Molten Materials

Towards constraining Mars' thermal evolution using machine learning

2021 ◽  
Author(s):  
Siddhant Agarwal ◽  
Nicola Tosi ◽  
Pan Kessel ◽  
Sebastiano Padovan ◽  
Doris Breuer ◽  
...  
Keyword(s):  
Activation Energy ◽  
Enrichment Factor ◽  
Activation Volume ◽  
Initial Conditions ◽  
Thermal Evolution ◽  
Diffusion Creep ◽  
Dynamic Simulations ◽  
Mixture Density ◽  
Lithospheric Thickness ◽  
Mantle Temperature

<p>The thermal evolution of terrestrial planets depends strongly on several parameters and initial conditions that are poorly constrained. Often, direct or indirect observables from planetary missions such as elastic lithospheric thickness, crustal thickness and duration of volcanism are inverted to infer the unknown parameter values and initial conditions. The non-uniqueness and non-linearity of this inversion necessitates a probabilistic inversion framework. However, due to the expensive nature of forward dynamic simulations of thermal convection , Markov Chain Monte Carlo methods are rarely used. To address this shortcoming, some studies have recently shown the effectiveness of Mixture Density Networks (MDN) (Bishop 1995) in being able to approximate the posterior probability using only the dataset of simulations run prior to the inversion (Meier et al. 2007, de Wit et al. 2013, Käufl et al. 2016, Atkins et al. 2016).</p><p>Using MDNs, we systematically isolate the degree to which a parameter can be constrained using different “present-day” synthetic observables from 6130 simulations for a Mars-like planet. The dataset – generated using the mantle convection code GAIA (Hüttig et al. 2013)- is the same as that used by Agarwal et al. (2020) for a surrogate modelling study.</p><p>The loss function used to optimize the MDN (log-likelihood) provides a single robust quantity that can be used to measure how well a parameter can be constrained. We test different numbers and combinations of observables (heat flux at the surface and core-mantle boundary, radial contraction, melt produced, elastic lithospheric thickness, and duration of volcanism) to constrain the following parameters: reference viscosity, activation energy and activation volume of the diffusion creep rheology, an enrichment factor for radiogenic elements in the crust, and initial mantle temperature. If all observables are available, reference viscosity can be constrained to within 32% of its entire range (10<sup>19</sup>−10<sup>22</sup> Pa s), crustal enrichment factor (1−50) to within 15%, activation energy (10<sup>5</sup>−5×10<sup>5</sup> J mol-1 ) to within 80%, and initial mantle temperature (1600−1800K) to within 39%. The additional availability of the full present-day temperature profile or parts of it as an observable tightens the constraints further. The activation volume (4×10<sup>-6</sup> −10×10<sup>-6</sup>  m<sup>3</sup> mol<sup>-1</sup>) cannot be constrained and requires research into new observables in space and time, as well as fields other than just temperature. Testing different levels of uncertainty (simulated using Gaussian noise) in the observables, we found that constraints on different parameters loosen at different rates, with initial temperature being the most sensitive. Finally, we present how the marginal MDN proposed by Bishop (1995) can be modified to model the joint probability for all parameters, so that  the inter-parameter correlations and the associated degeneracy can be capture, thereby providing a more comprehensive picture of all the evolution scenarios that fit given observational constraints.</p>

scholarly journals Dislocation and diffusion creep of synthetic anorthite aggregates

2000 ◽  
Vol 105 (B11) ◽  
pp. 26017-26036 ◽  
Author(s):  
E. Rybacki ◽  
G. Dresen
Keyword(s):  
Diffusion Creep ◽  
And Diffusion

Grain growth and the lifetime of diffusion creep deformation

2011 ◽  
Vol 360 (1) ◽  
pp. 257-272 ◽  
Author(s):  
Mark A. Pearce ◽  
John Wheeler
Keyword(s):  
Grain Growth ◽  
Creep Deformation ◽  
Diffusion Creep
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