Application Of Hollow Spheres Research Articles

An Experimental Investigation of the Dynamic Mechanical Behaviors of Hollow Spheres Filled Syntactic Foam

Dynamic mechanical behaviors are critical to the engineering applications of hollow spheres filled syntactic foams. The potential of such composites cannot be fully realized unless the effects of strain rate on their mechanical properties are fully understood. In this study, both the compressive and the tensile behaviors of an epoxy syntactic foam filled by ceramic microspheres were experimentally investigated over the strain rate range from 0.001 to 2000 s-1. The compressive and tensile tests at high strain rates were carried out by means of split Hopkinson pressure bar (SHPB) and split Hopkinson tensile bar (SHTB), respectively. The stress-strain responses and failure mechanisms were examined quantitatively and qualitatively. The experimental results indicate that both the compressive and the tensile behaviors of syntactic foam are highly sensitive to strain rate. Moreover, a comparison of the stress-strain curves suggests that the compressive and tensile behaviors are dominated by different failure mechanisms, which consequently lead to distinct effects of strain rate on the compressive and tensile behaviors of syntactic foam.

Sonochemically assisted synthesis and application of hollow spheres, hollow prism, and coralline-like ZnO nanophotocatalyst

Nanosheet-based microspheres of ZnO with hierarchical structures, hollow prism, and coralline-like ZnO nanostructures were successfully prepared by ultrasonic irradiation in acidic ionic liquids (AILs). The hollow spherical is made up of many thin petals, the thickness of which is only about 90 nm. In the presence of AIL2, the one prepared at a frequency of 40 kHz is a mixture of nanofibers with diameters ranging from less than 30 nm to about 100 nm. ZnO nanostructure (with AIL1) reveals lozenge-shape hollow prism structures. The products were hollow prism structure covered with some nanometric-size nanoparticles. The average size of the nanoparticles is in the range of 40–80 nm. It is found that the ultrasonic irradiation time, ultrasonic frequency, and the AILs influence the growth mechanism and optical properties of ZnO nanostructures. Producing Zno nanostructures by different traditional methods (e.g., hydrothermal method) requires basic media. These methods are not economical and environmentally friendly in many industrial processes. In so doing, a critical problem has been the point that, normally, a high concentration of base causes reactor metal corrosion. This is a simple and low-cost method, which can be expected to be applied in industry in the future. Also, importantly, the structures synthesized in this experiment can indicate a new way to construct nanodevices by self-organization in one step.