Electromagnetic field angular momentum in condensed matter systems

Various electromagnetic systems can carry an angular momentum in their {\bf E} and {\bf B} fields. The electromagnetic field angular momentum (EMAM) of these systems can combine with the spin angular momentum to give composite fermions or composite bosons. In this paper we examine the possiblity that an EMAM could provide an explanation of the fractional quantum Hall effect (FQHE) which is complimentary to the Chern-Simons explanation. We also examine a toy model of a non-BCS superconductor (e.g. high $T_c$ superconductors) in terms of an EMAM. The models presented give a common, simple picture of these two systems in terms of an EMAM. The presence of an EMAM in these systems might be tested through the observation of the decay modes of a charged, spin zero unstable particle inside one of these systems.Comment: 17 pages, no figures, to be published in Phys. Rev.

The problem of political science and practical politics

Copyright @ 2006 The AuthorsWe reflect on the reasons why there is not a greater and more fruitful relationship between those who seek to understand policy and the political process from academia and those with a similar task in ‘practical politics’. We attribute this lack of engagement to three core factors: (1) from without, instrumental government visions of political science perpetuate the view that the discipline exists to serve those with power; (2) from within, scientism and abstraction diminish the discipline's stock of ‘usable’ product for ‘practical politics’; and (3) where relevant research exists, its uptake is hampered by limited communication between these spheres

Participation in Transition(s):Reconceiving Public Engagements in Energy Transitions as Co-Produced, Emergent and Diverse

This paper brings the transitions literature into conversation with constructivist Science and Technology Studies (STS) perspectives on participation for the first time. In doing so we put forward a conception of public and civil society engagement in sustainability transitions as co-produced, relational, and emergent. Through paying close attention to the ways in which the subjects, objects, and procedural formats of public engagement are constructed through the performance of participatory collectives, our approach offers a framework to open up to and symmetrically compare diverse and interconnected forms of participation that make up wider socio-technical systems. We apply this framework in a comparative analysis of four diverse cases of civil society involvement in UK low carbon energy transitions. This highlights similarities and differences in how these distinct participatory collectives are orchestrated, mediated, and subject to exclusions, as well as their effects in producing particular visions of the issue at stake and implicit models of participation and ‘the public’. In conclusion we reflect on the value of this approach for opening up the politics of societal engagement in transitions, building systemic perspectives of interconnected ‘ecologies of participation’, and better accounting for the emergence, inherent uncertainties, and indeterminacies of all forms of participation in transitions

Deliberative and epistemic approaches to democracy

Deliberative and epistemic approaches to democracy are two important dimensions of contemporary democratic theory. This chapter studies these dimensions in the emerging ecosystem of civic and political participation tools, and appraises their collective value in a new distinct concept: linked democracy. Linked democracy is the distributed, technology-supported collective decision-making process, where data, information and knowledge are connected and shared by citizens online. Innovation and learning are two key elements of Athenian democracies which can be facilitated by the new digital technologies, and a cross-disciplinary research involving computational scientists and democratic theorists can lead to new theoretical insights of democracy

Drastic enhancement of carbon dioxide adsorption in fluoroalkyl-modified poly(allylamine)

Polyamine-based carbon dioxide sorbents suffer from a seesaw relationship between amine content and amine efficiency. High polyamine loadings equate to increased amine contents, but often at the expense of amine efficiency. Carbon dioxide mass transport in compact polymers is severely limited, especially at ambient temperature. High polymer contents curtail diffusion pathways, hindering CO2 from reaching and reacting with the numerous amine functions. Here, we overcome this issue using poly(allylamine) (PAA) grafted with short fluoroalkyl chains and then cross-linked with C60. As experimentally evidenced by positron annihilation lifetime spectroscopy, the incorporation of fluoroalkyl chains generates free volume elements that act as additional diffusion pathways within the material. The inclusion of void volume in fluoroalkyl-functionalized PAA sorbents results in radically increased CO2 uptakes and amine efficiencies in diluted gas streams at room temperature, including simulated air. We speculate that the hydrophobic fluorinated functions interfere with the strong amine hydrogen bonding network disrupting and consequently altering the packing and conformation of the polymer chains. The evidence presented here is a blueprint for the development of more efficient amine-based CO2 sorbents. This journal i