2,521 research outputs found

    Screening of energy efficient technologies for industrial buildings' retrofit

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    This chapter discusses screening of energy efficient technologies for industrial buildings' retrofit

    The fans united will always be connected: building a practical DTN in a football stadium

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    Football stadia present a difficult environment for the deployment of digital services, due to their architectural design and the capacity problems from the numbers of fans. We present preliminary results from deploying an Android app building an ad hoc network amongst the attendees at matches at Brighton and Hove Albion's AMEX stadium, so as to share the available capacity and supply digital services to season ticket holders. We describe the protocol, how we engaged our users in service design so that the app was attractive to use and the problems we encountered in using Android

    Development of a Pseudo-Uniform Structural Quantity for the Active Control of Structural Radiation

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    Active noise control has been a highly researched field over the past few decades but the active control of the radiating structures has recently excited interest. Multiple structural quantities and their relationships to acoustic radiation are investigated. This paper also looks at the control of a new structural quantity developed taking advantage of the principle of Rayleigh’s integral and radiated power being strongly dependent on volume velocity. The benefit of this new quantity is that while most active control techniques are highly dependent on sensor location, this technique is not. The control of this quantity and its effect on radiated power and acoustic radiation modes is presented

    Mediating exposure in public interactions

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    Mobile computing and public interactions together open up a new range of challenges in interaction design. To date a very gregarious model of interaction has been assumed. However, the public setting will invoke feelings of shyness and a desire to control the personal exposure associated with interactions. In this paper we discuss these issues and our initial tests of a system which affords a control beyond "engage or don't engage"

    Charge Fractionalization on Quantum Hall Edges

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    We discuss the propagation and fractionalization of localized charges on the edges of quantum Hall bars of variable widths, where interactions between the edges give rise to Luttinger liquid behavior with a non-trivial interaction parameter g. We focus in particular on the separation of an initial charge pulse into a sharply defined front charge and a broader tail. The front pulse describes an adiabatically dressed electron which carries a non-integer charge, which is \sqrt{g} times the electron charge. We discuss how the presence of this fractional charge can, in principle, be detected through measurements of the noise in the current created by tunneling of electrons into the system. The results are illustrated by numerical simulations of a simplified model of the Hall bar.Comment: 15 page

    Are there sharp fractional charges in Luttinger liquids?

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    We examine charge fractionalization by chiral separation in a one-dimensional fermion system described by Luttinger liquid theory. The focus is on the question of whether the fractional charges are quantum mechanically sharp, and in the analysis we make a distinction between the global charge, which is restricted by boundary conditions, and the local charge where a background contribution is subtracted. We show, by way of examples, that fractional charges of arbitrary values, all which are quantum mechanically sharp, can be introduced by different initial conditions. Since the system is gapless, excitations of arbitrary low frequency contribute to the fluctuations, it is important to make a precise definition of sharp charges, and this we we do by subtraction of the ground state contribution. We very briefly comment on the relevance of our analysis for proposed experiments.Comment: One reference update

    The Effectiveness of Conservation Reserves: Land Tenure Impacts upon Biodiversity across Extensive Natural Landscapes in the Tropical Savannahs of the Northern Territory, Australia

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    This study examines whether there is a biodiversity benefit (“dividend”) associated with the existence and management of conservation reserves in the extensive and largely natural landscape of northern Australia. Species richness and abundance of vertebrate fauna and the intensity of a range of disturbance factors were compared across a set of 967 sampled quadrats, located either in pastoral lands, Indigenous lands or conservation reserves, with all sampled quadrats within a single vegetation type (open forests and savannah woodlands dominated by Eucalyptus miniata and/or E. tetrodonta). The relationships with land tenure varied between major taxonomic groups, but generally (and particularly for threatened species) values were highest for conservation reserves. This “biodiversity dividend” associated with conservation reserves is considered to be due to the effects of management rather than because conservation reserves were established on lands supporting atypically high conservation values. The impact of weeds and (unsurprisingly) livestock was greatest on pastoral lands, and pig impact was greatest in conservation reserves. Although pastoral and Indigenous lands supported lower biodiversity tallies than reserved lands, the conservation values of reserved lands in this region are probably substantially supported by the maintenance of relatively intact ecological systems across all lands
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