Research@THEA (new)The Research@THEA digital repository system captures, stores, indexes, preserves, and distributes digital research material.https://research.thea.ie:4432024-03-28T15:38:49Z2024-03-28T15:38:49ZTest documentTest, Testhttps://research.thea.ie/handle/20.500.12065/47732024-03-28T15:16:52Z2021-01-01T00:00:00ZTest document
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2021-01-01T00:00:00ZTesthttps://research.thea.ie/handle/20.500.12065/47722024-03-28T14:53:17Z2024-01-01T00:00:00ZTest
2024-01-01T00:00:00ZTargeting bacterial nanocellullose properties through tailored downstream techniquesDa Silva Pereira, Everton HenriqueMojicevic, MarijaTas, Cunety ErdincLanzagorta Garcia, EduardoFournet, Margaret Brennanhttps://research.thea.ie/handle/20.500.12065/47712024-03-28T14:39:27Z2024-03-02T00:00:00ZTargeting bacterial nanocellullose properties through tailored downstream techniques
Da Silva Pereira, Everton Henrique; Mojicevic, Marija; Tas, Cunety Erdinc; Lanzagorta Garcia, Eduardo; Fournet, Margaret Brennan
Bacterial nanocellulose (BNC) is a biodegradable polysaccharide with unique properties that make it an attractive material for various industrial applications. This study focuses on the strain Komagataeibacter medellinensis ID13488, a strain with the ability to produce high yields of BNC under acidic growth conditions and a promising candidate to use for industrial production of BNC. We conducted a comprehensive investigation into the effects of downstream treatments on the structural and mechanical characteristics of BNC. When compared to alkaline-treated BNC, autoclave-treated BNC exhibited around 78% superior flexibility in average, while it displayed nearly 40% lower stiffness on average. An SEM analysis revealed distinct surface characteristics, indicating differences in cellulose chain compaction. FTIR spectra demonstrated increased hydrogen bonding with prolonged interaction time with alkaline solutions. A thermal analysis showed enhanced thermal stability in alkaline-treated BNC, withstanding temperatures of nearly 300 °C before commencing degradation, compared to autoclaved BNC which starts degradation around 200 °C. These findings provide valuable insights for tailoring BNC properties for specific applications, particularly in industries requiring high purity and specific mechanical characteristics.
2024-03-02T00:00:00ZNumerical studies of ram-air Intake for near-earth satellitesRavuri, NishitaScully, StephenVashishtha, Ashishhttps://research.thea.ie/handle/20.500.12065/47622024-03-23T03:01:57Z2024-01-01T00:00:00ZNumerical studies of ram-air Intake for near-earth satellites
Ravuri, Nishita; Scully, Stephen; Vashishtha, Ashish
The operation of satellites in Earth orbits with altitudes lower than 450 km involves dealing
with rarefied atmosphere environment. To compensate for the aerodynamic drag present
in this low-density atmosphere, satellites employ traditional Electric Propulsion, EP (limited
operational life) or Air-Breathing Electric Propulsion Systems, ABEP (longer operational life).
Careful geometric design of intakes of ABEP systems is critical for its performance. The
main motivation of this research is 1) to understand the complex flow around basic intake
configurations of ABEP systems in high-speed rarefied environment- using Direct Monte
Carlo Simulation (DSMC) methods, and 2) to design compression-assisted air-breathing intake
geometry operating efficiently at various orbital speeds for VLEO/SLEO satellite applications.
Two-dimensional axisymmetric, time-dependent Direct Simulation Monte-carlo (DSMC) method
has been utilized based on open-source SPARTA DSMC Simulator for various intake geometries
at three relevant altitudes. Initial simulations of basic hollow cylinder (straight duct) geometry
were run, followed by an analysis of different convergent angles for converging duct intakes,
for both specular and diffuse gas-surface interactions. The results have been analysed for the
collection efficiencies, mass flow rates at the entry and exit planes, drag force and the number
density profiles. It was observed that with increase in altitude, there is a considerable decrease
in the collection efficiencies under diffuse reflection conditions, and a considerable increase of
drag coefficients under specular reflection conditions
2024-01-01T00:00:00Z