Keywords : percolation threshold

A New Epidemic Spreading Model to Predict the Spread and Accumulation of Corona Virus (COVID-19) Positive Cases as a Function of Time

Richard D. Sudduth

Advanced Materials Letters, 2021, Volume 12, Issue 7, Pages 1-8
DOI: 10.5185/amlett.2021.071644

Recently an article describing a new model to predict the dominant S shaped curve of the percolation threshold for electrical conducting composites was published by this author. This model was essentially the first to successfully address to whole concentration range for electrically conducting composites with the same model. Several possible applications where this new percolation threshold model might also be applicable were indicated in this article. One of these applications was the spread of disease in a population during a disease epidemic. At this point, this new Epidemic Spreading Model has been successful in predicting the spread of the Corona Virus (COVID-19) in the United States from the beginning of the accumulation of positive cases on January 22, 2020 using Corona Virus (COVID-19) data collected by Johns Hopkins University.  Interestingly, this model also appears to be able to separate the disease propagation from the disease mitigation. This model has also been reasonably successful in predicting the spread of the Corona Virus (COVID-19) worldwide as well. In addition, when the model values for the magnitude of the separate populations were neutralized it was apparent that the growth of the epidemic in the USA was significantly greater than that experienced by the World data.

Characterization of the Interfacial Surface Energy for Composite Electrical Conduction Measurements using Two Full Range Percolation Threshold Models

Richard D. Sudduth

Advanced Materials Letters, 2020, Volume 11, Issue 3, Pages 1-12
DOI: 10.5185/amlett.2020.031484

Two full concentration range percolation threshold models were evaluated for three different carbon fillers in both Nylon 6,6 and Lexan.  A new Modified Landauer Model was introduced in this study and compared with a Percolation Threshold Model recently published by this author. These models were then utilized to address how to best characterize the interfacial surface energy, gpf, for composite electrical conduction measurements using Clingerman’s data. Three different models used for calculating the interfacial surface energies, gpf, were evaluated in this study. It was found that solid measurements used in calculating the Fowkes equation for the interfacial surface energy gave the most consistent correlations. A linear correlation was found between the Fowkes Interfacial surface energy and the b constant designated as the insulation surface interaction magnitude from the new Percolation Threshold Model. In addition, three concurrent mathematical conditions were found to occur at the same concentration for both the new percolation threshold models yielding S-shaped curves in this study.  These conditions include the concentration at the Inflection Point, the concentration at the maximum slope and the maximum extrapolated percolation threshold concentration calculated at the same concentration.