Numerical simulation of an open-air plasma jet using a multi-species reacting flow CFD code

Ivory nuts, produced by palms from the genus Phytelephas, possess a hard and microporous endosperm with a strong resemblance to elephant ivory. The nuts sustainable appeal made them popular as eco-friendly substitutes to ivory since they promote the development of forest communities without contributing to deforestation and animal poaching. In addition, they have been commercialized as microbeads to replace microplastics in cosmetic applications. However, this material is vulnerable to deterioration by micro-organisms and insects, as they are predominantly constituted by β-1,4-mannan, a hydrophilic polysaccharide similar to cellulose. In this context, seed endosperm was treated for 80 s by an atmospheric air plasma jet so as to modify its wettability, as plasma has been widely studied recently for seed disinfection and surface modification. Plasma treated samples were characterized by the water contact angle, AFM, and Raman imaging. Water contact angle results showed an increase from (31.5 ± 8.7)º to (78.9 ± 5.4)º, indicating incorporation of hydrophobic moieties to the sample surface. In turn, AFM images demonstrate the formation of a rough and heterogeneous coating that resembles epicuticular wax layers. Furthermore, principal component analysis of Raman imaging results evidenced contributions from wax (1156, 1170 and 1410 cm-1), carbohydrates (1020, 1080 and 1106 cm-1), and lignin (1573, 1635 and 1662 cm-1). These results indicate that plasma treatment promoted the migration of hydrophobic waxes to the surface and their crosslinking with fragmented cell wall material such as mannan, xylan, and lignin, promoting seed hydrophobization with no need for additional precursors or generation of side products.

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Full-Scale Numerical Simulation of Plasma-Sprayed Functionally Gradient Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.75.1 ◽

2009 ◽

Vol 75 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Fu Chi Wang ◽

Qun Bo Fan ◽

Lu Wang ◽

Quan Sheng Wang ◽

Zhuang Ma

Keyword(s):

Numerical Simulation ◽

Three Dimensional ◽

Plasma Jet ◽

Deposition Process ◽

Full Scale ◽

Temperature History ◽

Functionally Gradient Materials ◽

Gradient Materials ◽

Functionally Gradient ◽

Plasma Sprayed

To develop novel and advanced thermal barrier coatings, full-scale numerical simulation of plasma-sprayed functionally gradient materials is conducted in this paper, including the prediction of basic parameters at the nozzle exit, simulation of three dimensional simulation of the plasma jet, modeling of the interaction between the plasma jet and the particles, calculation of flight trajectories and temperature history of flying metal and ceramic particles, the interaction between the molten particles and the substrate, as well as the deposition process of the coatings. Various complex phenomena, such as turbulent effects with chemical reactions in the plasma jet, dispersion status of the particles onto the substrate, and the composition distribution of the functionally gradient materials, are fully taken into account. The numerical simulation results are found to be in good agreement with experimental evidence.

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Numerical simulation of a constant current density discharge in a flowing air plasma

10.2514/6.1999-3477 ◽

1999 ◽

Cited By ~ 1

Author(s):

Manoj Nagulapally ◽

Graham Candler ◽

Christophe Laux ◽

Charles Kruger

Keyword(s):

Numerical Simulation ◽

Current Density ◽

Constant Current ◽

Air Plasma ◽

Constant Current Density

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