Mechanical Testing of Cross-linked Silica Aerogel Impregnated Silicone for Cryogenic Tank Applications

Sabri, Firouzeh; Marchetta, Jeffrey G.; Faysal, K. M. Rifat; Hewitt, Robert; Roan, Esra

doi:10.2514/6.2012-1117

Cited by 1 publication

(1 citation statement)

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“…In our discussions we are assuming a uniform and homoge neous particle distribution and dispersion. 1 wt% to 25 wt% the composite material became stiffer, by a noticeable change in its Young's modulus (figure 7(c)) which has been observed previously and is supported by published literature [22][23][24][25]. In the case of La 2 O 2 S:Eu (1.0%) however, an increase in powder concentration from 1 to 25 wt% surprisingly did not lead to a noticeable change in Young's modulus (figure 7(c)), and, at low strains the values remained very close to one another.…”

Section: Tensile Propertiessupporting

confidence: 89%

Spincoat-fabricated multilayer PDMS-phosphor composites for thermometry

Parajuli

Allison

Sabri

2017

Meas. Sci. Technol.

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Phosphor thermometry offers unique advantages over traditional forms of temperature sensing. Polymer-encapsulated phosphor powders provide versatility and flexibility not achievable when using the thermographic phosphors in powder form. By encapsulating the powder in a polymeric sleeve custom devices with unique properties can be created. Here, the authors report on the design, synthesis, and characterization of the first multilayer thermographic phosphor structure. A thin layer of neat PDMS, Sylgard 184, was sandwiched between two layers of La2O2S:Eu phosphor-doped PDMS. The thicknesses ranged from 0.15 to 4 mm depending on spin speed. The temperature dependent luminescence of the structure was characterized from −40 °C to 75 °C, in a low humidity environmental chamber. Results show suitability for thermometry in this range. In addition, for design guidance, quantitative values for thermal conductivity and stress/strain characteristics versus phosphor loading percentage and temperature were measured. Thermal conductivities ranged from 0.15 W mK−1 for the Sylgard 184 to a value between 0.3 and 0.4 W mK−1 for pure phosphor powder for temperatures from −55 °C to 195 °C. Tensile properties for a strain of up to 1 revealed differences between the different phosphor loadings and phosphor batches. Young’s modulus for the spincoat layered materials was between 1.2 and 1.4 N mm−2 and 0.8 for drop casted samples.

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Section: Tensile Propertiessupporting

confidence: 89%