Segmental dynamics and physical aging of polystyrene/silver nanocomposites

We report the complicated variation trend of calorimetric Tg and physical aging in PS/Ag nanocomposites, despite the invariant segmental dynamics with increasing silver nanoparticle loading.

An Overview of Strut-and-Tie Model and its Common Challenges

B-Regions are parts of the structure in which Bernoulli's principle of straight-line strain is used. D-Regions are parts of the structure with a complicated variation in strain. In essence, D-Regions contain the parts of structure which are near to the concentrated forces or steep changes in geometry which are so-called geometrical discontinuities or static discontinuities. Strut-and-Tie Model (STM) is one of the best models to analyse the D-regions. Nevertheless, according to the existing literature, there are still some challenges about STM which are addressed in this paper. STM and its details are investigated to show its common challenges presents some recommendations to overcome these challenges. According to this review, the major challenges in STM are related to the strut effectiveness factor, static uncertainties of STM, strain compatibility, and anchorage requirements in STM. The scope of this research is confined to the two dimensional STM.

Ultrasonic studies of the electronic structure of hexagonal metal crystals II. Superconducting state in zinc and cadmium

Measurements have been made of the temperature dependence of the attenuation of longitudinal ultrasound in the superconducting states of pure zinc and cadmium for propagation along the and <0001>, <101 ¯ 0> and <112 ¯ 0> directions, at frequencies from 40 to 160 MHz. This temperature dependence has been interpreted in terms of an energy gap parameter A = 2∆(0)/ kT c . In zinc, for T < ½ T c , A was found to be 3.41 ± 0.1, 3.79 ± 0.1 and 3.64 ± 0.1 for the <0001>, <101 ¯ 0> and <122 ¯ 0> directions respectively. The corresponding values for cadmium were 3.29 ± 0.1, 2.80 ± 0.1 and 3.87 ± 0.1. A simple model proposed by Hays for the distribution of the energy gaps on the Fermi surface of zinc does not explain these results, and a more realistic model has been proposed. The main features of the proposed energy-gap distributions in zinc and cadmium are that the electrons on the third band lens have larger energy gaps than those on the second band monster, over which there is a large and complicated variation.