scholarly journals A continuum mixture model for steady detonation using a multiphase-based closure

2018 ◽  
Author(s):  
Michael Crochet
Keyword(s):  
Mixture Model ◽  
Continuum Mixture Model ◽  
Steady Detonation

Experimental Validation of Continuum Mixture Model for Binary Alloy Solidification

1997 ◽  
Vol 119 (4) ◽  
pp. 783-791 ◽  
Author(s):  
M. J. M. Krane ◽  
F. P. Incropera
Keyword(s):  
Mixture Model ◽  
Solidification Process ◽  
Scaling Analysis ◽  
Permeability Model ◽  
Alloy Solidification ◽  
Permeability Constant ◽  
Dendritic Array ◽  
Continuum Mixture Model ◽  
Composition Profiles ◽  
Alloy Microstructure

Experiments were performed with binary metal alloys to validate a continuum mixture model for alloy solidification. Ingots of two compositions, Pb-20%Sn and Pb-40%Sn, were cast in a permanent mold, and the solidification process was simulated. Temperature histories were measured during casting, and composition profiles were found in the solidified ingot. Dendritic arm spacings were found from optical micrographs of the alloy microstructure and used to determine a constant in the Blake-Kozeny submodel for the mushy zone permeability in the liquid-solid interaction term of the momentum equations. Scaling analysis from a previous work and a large uncertainty in the permeability constant suggested that predictions of the composition are extremely sensitive to the choice of a permeability model. Three simulations of each casting were performed using the permeability constant as a parameter, and measured temperatures and compositions were compared with predictions based on different model constants. In the region of the liquidus interface, where all of the significant advection of solute takes place, the results suggest that the Blake-Kozeny model based on measured dendritic arm spacings significantly underpredicts the resistance of the dendritic array to fluid flow.

scholarly journals Shock structure for the seven-equation, two-phase continuum-mixture model

2021 ◽  
pp. 1-32
Author(s):  
John Bohdan Bdzil ◽  
Ashwani Kumar Kapila ◽  
Michael Patrick Hennessey
Keyword(s):  
Mixture Model ◽  
Shock Structure ◽  
Two Phase ◽  
Continuum Mixture Model

The association of Raynaud’s phenomenon/syndrome with scleroderma and Sjögren’s syndrome – a meta-analysis

VASA ◽  
2008 ◽  
Vol 37 (Supplement 73) ◽  
pp. 26-32 ◽  
Author(s):  
Schlattmann ◽  
Höhne ◽  
Plümper ◽  
Heidrich
Keyword(s):  
Quantitative Analysis ◽  
Sjögren’S Syndrome ◽  
Mixture Model ◽  
Sjögren's Syndrome ◽  
Meta Analysis ◽  
Sjogren’S Syndrome ◽  
Sjogren's Syndrome ◽  
Raynaud’S Syndrome ◽  
Raynaud's Syndrome ◽  
Sjögren‘S Syndrome

Background: In order to analyze the prevalence of Raynaud’s syndrome in diseases such as scleroderma and Sjögren’s syndrom – a meta-analysis of published data was performed. Methods: The PubMed data base of the National Library of Medicine was used for studies dealing with Raynaud’s syndrome and scleroderma or Raynaud’s syndroem and Sjögren’s syndrom respectively. The studies found provided data sufficient to estimate the prevalence of Raynaud’s syndrome. The statistical analysis was based on methods for a fixed effects meta-analysis and finite mixture model for proportions. Results: For scleroderma a pooled prevalence of 80.9% and 95% CI (0.78, 0.83) was obtained. A mixture model analysis found four latent classes. We identified a class with a very low prevalence of 11%, weighted with 0.15. On the other hand there is a class with a very high prevalence of 96%. Analysing the association with Sjögren’s syndrome, the pooled analysis leads to a prevalence of Raynaud’s syndrome of 32%, 95% CI(26.7%, 37.7%). A mixture model finds a solution with two latent classes. Here, 38% of the studies show a prevalence of 18.8% whereas 62% observe a prevalence of 38.3%. Conclusion: There is strong variability of studies reporting the prevalence of Raynaud’s syndrome in patients suffering from scleroderma or Sjögren’s syndrome. The available data are insufficient to perform a proper quantitative analysis of the association of Raynaud’s phenomenon with scleroderma or Sjögren’s syndrome. Properly planned and reported epidemiological studies are needed in order to perform a thorough quantitative analysis of risk factors for Raynaud’s syndrome.

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