A lightweight three-phase Fluid Catalytic Cracking riser model for real-time simulation and interactive three-dimensional visualization

International audienceIn this paper, a lightweight physical model and a fast numerical solver are proposed for the rendering of fluid catalytic cracking (FCC) dynamics in the riser cylinder reactor part of the FCC unit. For Real Time requirements, a trade-off between the model fidelity and numerical complexity is needed. The choice of the physical model and the way to solve it numerically is here completely driven by the Real Time virtual reality requirements on a standard Personal Computer. It has been possible to design a real time numerical model able to show the three-phase flow dynamics depending on design parameters (number of oil injection inlets, injection angles, flow rates, temperature of cracking). The obtained flow is qualitatively in agreement with what is expected in such kind of reactive flows: expansion zones, recirculating zones for catalyst, turbulence, privileged paths for the gas phase, etc. Of course, the rendering is purely qualitative, but accurate enough to reproduce the emerging behaviors of the flow and roughly understand what happens in a riser reactor. This is of course important from the Engineering point of view. A Graphic User Interface (GUI) allows for near-Real Time (RT) user interaction on environmental parameters with instantaneous response of the flow. A VTK-based visualization module allows us to visualize the three-dimensional fields of the three phases, simultaneously or independently. The software was built with open source technologies including Python, VTK, SWIG for C++ wrapping and wxPython and is portable over different operating systems like MS Windows and Linux. We think that this work is a new milestone toward a whole FCC unit closed-loop control simulator in the context of training and engineering. The perspective to use Teraflop-enabled Double Precision multicore GPU (see [9]) co-processors in the next months should allow us to use much more computational cells and particles, maybe up to a speedup factor of about 100 for a convincing realistic rendering. Moreover, the ability with such hardware to create software binding between data arrays and rendering objects with a high rate of frames per second is an attractive feature for real time visualization, simulation and interaction

Deletion of TNFAIP6 gene in human keratinocytes demonstrates a role for TSG-6 to retain hyaluronan inside epidermis

TSG-6 is a soluble protein secreted in the extracellular matrix by various cell types in response to inflammatory stimuli. TSG-6 interacts with extracellular matrix molecules, particularly hyaluronan (HA), and promotes cutaneous wound closure in mice. Between epidermal cells, the discrete extracellular matrix contains HA and a tiny amount of TSG-6. However, challenges imposed to keratinocytes in reconstructed human epidermis revealed strong induction of TSG-6 expression, after exposure to T helper type 2 cytokines to recapitulate the atopic dermatitis phenotype or after fungal infection that causes secretion of cytokines and antimicrobial peptides. After both types of challenge, enhanced release of TSG-6 happens simultaneously with increased HA production. TSG-6 deficiency in N/TERT keratinocytes was created by inactivating TNFAIP6 using CRISPR/Cas9. Some TSG-6–/– keratinocytes analyzed through scratch assays tend to migrate more slowly but produce reconstructed human epidermis that exhibits normal morphology and differentiation. Few significant alterations were noticed by transcriptomic analysis. Nevertheless, reduced HA content in TSG-6–/– reconstructed human epidermis was observed, along with enhanced HA release into the culture medium, and this phenotype was even more pronounced after the challenging conditions. Reintroduction of cells producing TSG-6 in reconstructed human epidermis reduced HA leakage. Our results show a role for TSG-6 in sequestering HA between epidermal cells in response to inflammation