Interfacial shear strength and tensile properties of injection-molded, short- and long-glass fiber-reinforced polyamide 6,6 composites

Injection-molded short- and long-glass fiber/polyamide 6,6 composites were subjected to tensile tests. To measure the effectiveness of the fibers in reinforcing the composites, a computational approach was employed to compute the fiber– matrix ISS, orientation factor, reinforcement efficiency, tensile-, and fiber length-related properties. Although the LFCs showed great improvement in fiber characteristics compared to the SFCs, enhancement in tensile properties was small, which is believed to be due to the larger fiber diameter. Kelly–Tyson model provides good approximation for the computation of ISS and tensile-related properties.

Indigenous rights in Chile: National identity and majority group support for multicultural policies

We examine support for policies affecting indigenous ethnic minorities in Chile. Specifically, we examine the role of national group definitions that include the largest indigenous group—the Mapuche—in different ways. Based on questionnaire data from nonindigenous Chilean students (N = 338), we empirically distinguish iconic inclusion, whereby the Mapuche are seen as an important part of Chile's history and identity on the one hand, from egalitarian inclusion, which represents the Mapuche as citizens of equal importance to the nonindigenous majority on the other. Both forms of inclusion positively predict support for indigenous rights, independent of participants' political affiliation, strength of national identification, and social distance. A second study (N = 277) replicates this finding whilst controlling for right-wing authoritarianism, social dominance orientation, blind patriotism, and constructive patriotism. It also finds iconic inclusion to be predictive of a pro-Mapuche position regarding the unrest over the issue of ancestral land in 2009. We conclude that understanding how national identity affects attitudes about minority rights necessitates appreciating the importance of particular meanings of nationality, and not only the strength of identification.

Effect of column base strength on steel portal frames in fire

This paper presents the findings of a project part sponsored by an ICE Research and Development grant on portal frames in fire. The research reported here has also lead to a sucessful research grant from the IStructE. The paper describes a non-linear elasto plastic dynamic finite element model that captures the collapse of a portal frame in fire. It demonstrates that current guidance on the column base stiffness and strength, to prevent collapse, may in some cases be unconservative.

Interaction strength, food web topology and the relative importance of species in food webs

P>1. We established complex marine communities, consisting of over 100 species, in large subtidal experimental mesocosms. We measured the strength of direct interactions and the net strength of direct and indirect interactions between the species in those communities, using a combination of theoretical and empirical approaches.

Received signal strength in large-scale wireless relay sensor network: a stochastic ray approach

The authors consider a point percolation lattice representation of a large-scale wireless relay sensor network (WRSN) deployed in a cluttered environment. Each relay sensor corresponds to a grid point in the random lattice and the signal sent by the source is modelled as an ensemble of photons that spread in the space, which may 'hit' other sensors and are 'scattered' around. At each hit, the relay node forwards the received signal to its nearest neighbour through direction-selective relaying. The authors first derive the distribution that a relay path reaches a prescribed location after undergoing certain number of hops. Subsequently, a closed-form expression of the average received signal strength (RSS) at the destination can be computed as the summation of all signal echoes' energy. Finally, the effect of the anomalous diffusion exponent ß on the mean RSS in a WRSN is studied, for which it is found that the RSS scaling exponent e is given by (3ß-1)/ß. The results would provide useful insight into the design and deployment of large-scale WRSNs in future. © 2011 The Institution of Engineering and Technology.