Transport in porous media plays an essential role for many physical, engineering, biological and environmental processes. Novel synchrotron imaging techniques and image-based models have enabled more robust quantification of geometric structures that influence transport through the pore space. However, image-based modelling is computationally expensive, and end users often require, while conducting imaging campaign, fast and agile bulk-scale effective parameter estimates that account for the pore-scale details. In this manuscript we enhance a pre-existing image-based model solver known as OpenImpala to estimate bulk-scale effective transport parameters. In particular, the boundary conditions and equations in OpenImpala were modified in order to estimate the effective diffusivity in an imaged system/geometry via a formal multi-scale homogenisation expansion. Estimates of effective pore space diffusivity were generated for a range of elementary volume sizes to estimate when the effective diffusivity values begin to converge to a single value. Results from OpenImpala were validated against a commercial finite element method package COMSOL Multiphysics (abbreviated as COMSOL). Results showed that the effective diffusivity values determined with OpenImpala were similar to those estimated by COMSOL. Tests on larger domains comparing a full image-based model to a homogenised (geometrically uniform) domain that used the effective diffusivity parameters showed differences below 2 % error, thus verifying the accuracy of the effective diffusivity estimates. Finally, we compared OpenImpala’s parallel computing speeds to COMSOL. OpenImpala consistently ran simulations within fractions of minutes, which was two orders of magnitude faster than COMSOL providing identical supercomputing specifications. In conclusion, we demonstrated OpenImpala’s utility as part of an on-site tomography processing pipeline allowing for fast and agile assessment of porous media processes and to guide imaging campaigns while they are happening at synchrotron beamlines.
A pair of natural science researchers from Marymount Manhattan College has found that high levels of dog feces landing on sidewalks in New York city has resulted in high levels of bacteria in homes and businesses. In their paper published in the journal Indoor and Built Environment, Alessandra Leri and Marjan Khan describe collecting and testing environmental samples from a large number of sites on Manhattan's Upper East Side.
In other words ChatGPT is a Harvard grad
"It can provide an amazing answer or complete rubbish, all while acting completely confident in its answer."
“Mansplaining as a service.” Spot on.
Quoting @andrewfeeney: https://phpc.social/@andrewfeeney/109466122845775778
@[email protected] Christine Lemmer-Webber (@[email protected]) described ChatGPT as Mansplaining As A Service, and honestly I can’t think of a better description. A service that instantly generates vaguely plausible sounding yet totally fabricated and baseless lectures in an instant with unflagging confidence in its own correctness on any topic, without concern, regard or even awareness of the level of expertise of its audience.
Marc Abrahams
Edward Nirenberg
Prof Dynarski
Steven Op de beeck