Thermal conductivity measurements were performed on polyamide 12 and polyamide 11 powders containing carbon nanotubes using the transient plane source (TPS) technique. The effects of powder density and temperature on thermal conductivity were investigated, as well as the effects of using previously heated powder. The thermal conductivity was found to increase with increasing density. For tests involving fresh powder, the thermal conductivity was found to increase linearly with temperature. For the previously ...
A disc of a composite ceramic material composed of silicon nitride (Si3N4) and 20% hBN was prepared and its tribological characteristics were investigated by sliding a Si3N4 pin across its surface at different sliding speeds. The friction coefficient and wear coefficient were determined for the composite using two different test modes: one in which the pin was kept stationary and the disc was rotated on top of the pin, ...
The thermal and mechanical properties of concrete in which normal weight aggregate has been substituted with lightweight aggregates were investigated. The properties were found to be dependent on the volume fraction of the lightweight aggregate, as well as on the nature and quality of the aggregate. The addition of lightweight aggregates resulted in a decreased thermal conductivity, as well as a decreased thermal diffusivity in all samples. The compressive strength ...
A Portland cement-based composite was made using a copolymer as one of the ingredients, and the potential of the composite for the production of non-structural masonry systems was evaluated. It was found that the composite had a similar performance to that of commercial cellular concretes. The results also indicated that the incorporation of fly ash into mortars decreased the thermal conductivity of the composite....
Microcellular (methylmethacrylate)-(butyl acrylate)-(Methylmethacrylate) triblock copolymer foams were prepared by a foaming process using CO2. CO2 was first dissolved into sheets of the polymer, and then the pressure was released over different time periods, from 2 to 30 minutes. The density, cellular structure, and thermal conductivity of these foams were then investigated. It was determined that the density decreased with increasing depressurization time; however, the density did not change ...
