Doctor of Philosophy / Department of Biological & Agricultural Engineering / Ronaldo G. Maghirang / Nanostructured particles possess unique chemical and physical properties, making them
excellent candidates for air purification, smoke clearing, and obscuration. This research was
conducted to investigate the aerodynamic, charging, and infrared (IR) extinction properties of
nanostructured particles. Specific objectives were to: (1) measure the size distribution and
concentration of aerosolized nanostructured particles; (2) evaluate their IR extinction properties;
(3) determine their relative chargeability; and (4) numerically model their transport in enclosed
rooms.
The size distribution and concentration of two nanostructured particles (NanoActive®
MgO and MgO plus) were measured in an enclosed room. The particles differed in size
distribution and concentration; for example, the geometric mean diameters of NanoActive®
MgO and MgO plus were 3.12 and 11.1 [Mu]m, respectively.
The potential of nanostructured particles as IR obscurants was determined and compared
with other particles. Four groups of particles were considered: nanostructured particles
(NanoActive® MgO plus, MgO, TiO[subscript2]); nanorods (MgO, TiO[subscript2]); conventional particles (NaHCO[subscript3]
and ISO fine test dust); and common obscurants (brass, graphite, carbon black). The extinction
coefficients of the nanostructured particles were generally significantly smaller than those of the
other particles. Graphite flakes had the greatest mass extinction coefficient (3.22 m[superscript2]/g), followed
by carbon black (1.72 m[superscript2]/g), and brass flakes (1.57 m[superscript2]/g). Brass flakes had the greatest volume
extinction coefficient (1.64 m[superscript2]/cc), followed by NaHCO[subscript3] (0.93 m[superscript2]/cc), and ISO fine test dust
(0.91 m[superscript2]/cc).
The relative chargeability of nanostructured particles was also investigated. Selected
particles were passed through a Teflon tribocharger and their net charge-to-mass ratios were
measured. Tribocharging was able to charge the particles; however, the resulting charge was
generally small. NanoActive® TiO[subscript2] gained the highest net charge-to-mass ratio (1.21 mC/kg)
followed by NanoActive® MgO (0.81 mC/kg) and ISO fine test dust (0.66 mC/kg).
The transport of NanoActive® MgO plus and hollow glass spheres in an enclosed room
was simulated by implementing the discrete phase model of FLUENT. In terms of mass
concentrations, there was reasonable agreement between predicted and measured values for
hollow glass spheres but not for NanoActive® MgO plus. In terms of number concentration,
there was large discrepancy between predicted and measured values for both particles.
| Identifer | oai:union.ndltd.org:KSU/oai:krex.k-state.edu:2097/659 |
| Date | January 1900 |
| Creators | Pjesky, Susana Castro |
| Publisher | Kansas State University |
| Source Sets | K-State Research Exchange |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
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