Nanocomposites of acrylonitrile-butadiene-styrene (ABS) and nanosilica with different nanoparticle sizes and various loadings are prepared. Rheological experiments such as frequency sweep, strain sweep, and rotational test are performed to investigate the influence of nanoparticle loading and size on the viscoelastic properties of the nanocomposites. The results show that nanocomposites with higher filler loading and smaller particle size have both higher storage and loss moduli. Moreover, the results indicate that the storage modulus is more sensitive than loss modulus to filler loading and nanoparticle size. The smaller nanoparticles and higher filler loadings lead to the enhancement of nanoparticle surface area so that the viscoelastic properties are intensified through increase of polymer chain adsorption on nanoparticle, and creation of a network structure in the nanocomposites. The network structure causes changes to the rheological behavior of the nanocomposite such as solid-like behavior in the low-frequency region and reduction of the Newtonian region. The scanning electron microscopy micrographs revealed that the particle aggregates increase with particle size reduction and increasing nanoparticle content. We also used a nonlinear optimization to obtain the parameters of a multimode Maxwell model for low nanofiller content ABS/SiO 2 nanocomposites and found the relaxation times of the polymer chains increased with increasing nanoparticle content.

Plyometric training to increase physical ability and leads to increase of muscles power. The aim of the study was to assess the effects of short term plyometric training program on sprint, strength, and power and agility performance in non-athletic men. In this research, 40 non-athletic men (year 18-23) participated. The participants were chosen randomly and they participated in four tests strength (Swedish swimming, sit-ups), power (vertical jumps, Horizontal jumps), agility (Illinois Agility Test, T Agility Test) and 30 meters speed. The participants were divided into two groups, i.e. experimental (plyometric training) and control group (did not perform PT training). They participated in the training for 5 weeks and each week 1 session and each session 90 minutes. The results of the study revealed that in experimental groups, significant increase observed in Swedish swimming, horizontal jumps test and also significant decrease observed in 30 meters speed and test in comparison with control group (p-value of the respectively 0.001, 0.02, 0.00). The differences were significant not observed of agility test in comparison with control group. Conclusion: Therefore, it seems that plyometric training have been effective on the physical preparation indices and can improve the non athletes' performance.