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Experimental work is carried out to study the performance of nanoparticle enhanced phase change materials (NEPCMs) when applied to the Egyptian weather for indoor thermal comfort. Nanoparticle alumina and copper-oxide are used as the additive material into the PCMs 7, 11, 24, 26 and 29. The enhanced PCMs are characterized and tested for thermal performance during solidification and melting cycles. Observations are then made to conclude that, compared to the base fluid, PCM11 has the optimum performance for the Egyptian winter weather and PCM26 is the best for the summer conditions. PCM11 with a favorable phase change range ∼11–13∘C for Egyptian winter conditions, shows a reduction of melting time by over 10% when 5wt.% CuO nanoparticles (NPs) are added. Similarly, further to thermal stability and reduced corrosive action, PCM26 enhanced with 5wt.% CuO NPs has over 14% faster melting compared to the base fluid and does not undergo supercooling when tested for summer application. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites, which contain nanoparticles dispersed in a polymer matrix, provide improved properties at low filler loadings. These materials are already produced commercially, with twin-screw extrusion being the preferred process for compounding the nanoparticles and polymer melts. Several recent studies have demonstrated that nanoparticles can enter the body through inhalation, but the risk assessments for nanoparticle exposures are incomplete. Recently, concerns had been expressed that airborne nanoparticles released during compounding might present significant exposure to extruder operators. To assess the impact of the nanoparticles during twin-screw compounding of nanocomposites, researchers with experience in occupational and environmental health and polymer manufacturing monitored the compounding process for a model nanoalumina-containing nanocomposite using a TSI Fast Mobility Particle Spectrometer (FMPS). FMPS measurements were taken at background locations, source locations, and operators' breathing zones. In parallel to the FMPS real time measurement, airborne nanoparticles were collected using polycarbonate filters fitted with filmed grids driven by a personal air sampling pump. Filter samples were analyzed for particle morphology and elemental composition, and the results were found to be in good agreement with particle measurements by FMPS. Engineering controls and administrative controls were applied to reduce particle release from the compounding process and other operations in the laboratory. The administrative controls dramatically eliminated nanoparticles in the laboratory air, reducing total concentration by as much as 53 000 particles/cm3. Engineering controls were investigated and significant reductions of particle release were attained. The primary solution to reduce exposure level of nanoalumina is to isolate the releasing source. Overall, the engineering controls and administrative controls were effective in reducing airborne nanoparticle release during compounding. [ABSTRACT FROM AUTHOR]