Developing the egovernment research agenda

This paper presents an exploratory research project to determine the needs for future eGovernment research. The project aimed particularly at getting relevant stakeholder views as a contrast to the received academic wisdom or political rhetoric. This paper outlines the need for such fieldwork and discusses the methodology adopted to elicit the stakeholders’ views without influencing the debate. The VIEGO workshops have shown that an eGovernment research agenda will require a multi-disciplinary approach involving a combination of social, technological and organisational issues. The primary concerns of stakeholders are not to develop more novel IT but to acquire the means to cope with constant change, coordinate development and extend participation.UK’s Engineering Physical Sciences Research Council (EPSRC)-(grant EP/ D043840/1

Electronic transformation of government in the U.K.: a research agenda

This paper presents the findings of an exploratory research project into future e-Government (electronic Government) initiatives. The Virtual Institute for Electronic Government Research (VIEGO) project aimed at identifying and further developing the research agenda of e-Government based on a solid practical ground. As such, the paper offers a novel methodology in identifying the road map for future e-Government initiatives based on a series of workshops organised around the U.K. hosting a mixture of stakeholders involving both academics and parishioners. The analysis of the VIEGO workshops depicted that an e-Government research agenda involves a combination of social, technological and organisational issues at both governmental and individual citizen level, ultimately driven by empirical case-based experience and active participation in e-Government processes. Unlike other propositions for the future of e-Government offered in the e- Government literature, raised research questions not only originated from an analysis of e-Government literature but also on the outcome of brainstorming, reflections and contemplations throughout the duration of the project

Higher-order conservative interpolation between control-volume meshes: Application to advection and multiphase flow problems with dynamic mesh adaptivity

© 2016 .A general, higher-order, conservative and bounded interpolation for the dynamic and adaptive meshing of control-volume fields dual to continuous and discontinuous finite element representations is presented. Existing techniques such as node-wise interpolation are not conservative and do not readily generalise to discontinuous fields, whilst conservative methods such as Grandy interpolation are often too diffusive. The new method uses control-volume Galerkin projection to interpolate between control-volume fields. Bounded solutions are ensured by using a post-interpolation diffusive correction. Example applications of the method to interface capturing during advection and also to the modelling of multiphase porous media flow are presented to demonstrate the generality and robustness of the approach

Exactly solvable model of the 2D electrical double layer

We consider equilibrium statistical mechanics of a simplified model for the ideal conductor electrode in an interface contact with a classical semi-infinite electrolyte, modeled by the two-dimensional Coulomb gas of pointlike $\pm$ unit charges in the stability-against-collapse regime of reduced inverse temperatures $0\le \beta<2$. If there is a potential difference between the bulk interior of the electrolyte and the grounded interface, the electrolyte region close to the interface (known as the electrical double layer) carries some nonzero surface charge density. The model is mappable onto an integrable semi-infinite sine-Gordon theory with Dirichlet boundary conditions. The exact form-factor and boundary state information gained from the mapping provide asymptotic forms of the charge and number density profiles of electrolyte particles at large distances from the interface. The result for the asymptotic behavior of the induced electric potential, related to the charge density via the Poisson equation, confirms the validity of the concept of renormalized charge and the corresponding saturation hypothesis. It is documented on the non-perturbative result for the asymptotic density profile at a strictly nonzero $\beta$ that the Debye-H\"uckel $\beta\to 0$ limit is a delicate issue.Comment: 14 page

Sheath parameters for non-Debye plasmas: simulations and arc damage

This paper describes the surface environment of the dense plasma arcs that damage rf accelerators, tokamaks and other high gradient structures. We simulate the dense, non-ideal plasma sheath near a metallic surface using Molecular Dynamics (MD) to evaluate sheaths in the non-Debye region for high density, low temperature plasmas. We use direct two-component MD simulations where the interactions between all electrons and ions are computed explicitly. We find that the non-Debye sheath can be extrapolated from the Debye sheath parameters with small corrections. We find that these parameters are roughly consistent with previous PIC code estimates, pointing to densities in the range $10^{24} - 10^{25}\mathrm{m}^{-3}$. The high surface fields implied by these results could produce field emission that would short the sheath and cause an instability in the time evolution of the arc, and this mechanism could limit the maximum density and surface field in the arc. These results also provide a way of understanding how the "burn voltage" of an arc is generated, and the relation between self sputtering and the burn voltage, while not well understood, seems to be closely correlated. Using these results, and equating surface tension and plasma pressure, it is possible to infer a range of plasma densities and sheath potentials from SEM images of arc damage. We find that the high density plasma these results imply and the level of plasma pressure they would produce is consistent with arc damage on a scale 100 nm or less, in examples where the liquid metal would cool before this structure would be lost. We find that the sub-micron component of arc damage, the burn voltage, and fluctuations in the visible light production of arcs may be the most direct indicators of the parameters of the dense plasma arc, and the most useful diagnostics of the mechanisms limiting gradients in accelerators.Comment: 8 pages, 16 figure

A Force-Balanced Control Volume Finite Element Method for Multi-Phase Porous Media Flow Modelling

Dr D. Pavlidis would like to acknowledge the support from the following research grants: Innovate UK ‘Octopus’, EPSRC ‘Reactor Core-Structure Re-location Modelling for Severe Nuclear Accidents’) and Horizon 2020 ‘In-Vessel Melt Retention’. Funding for Dr P. Salinas from ExxonMobil is gratefully acknowledged. Dr Z. Xie is supported by EPSRC ‘Multi-Scale Exploration of Multi-phase Physics in Flows’. Part funding for Prof Jackson under the TOTAL Chairs programme at Imperial College is also acknowledged. The authors would also like to acknowledge Mr Y. Debbabi for supplying analytic solutions.Peer reviewedPublisher PD

Quantum Electrodynamics near a Huttner-Barnett dielectric

We build up a consistent theory of quantum electrodynamics in the presence of macroscopic polarizable media. We use the Huttner-Barnett model of a dispersive and absorbing dielectric medium and formulate the theory in terms of interacting quantum fields. We integrate out the damped polaritons by using diagrammatic techniques and find an exact expression for the displacement field (photon) propagator in the presence of a dispersive and absorbing dielectric half-space. This opens a new route to traceable perturbative calculations of the same kind as in free-space quantum electrodynamics. As a worked-through example we consider the interaction of a neutral atom with a dispersive and absorbing dielectric half-space. For that we use the multipolar coupling $\boldsymbol{\mu}\cdot\mathbf{D}$ of the atomic dipole moment to the electromagnetic displacement field. We apply the newly developed formalism to calculate the one-loop correction to the atomic electron propagator and find the energy-level shift and changes in the spontaneous decay rates for a neutral atom close to an absorptive dielectric mirror.Comment: 25 pages, 4 figure

Localizability of Wireless Sensor Networks: Beyond Wheel Extension

A network is called localizable if the positions of all the nodes of the network can be computed uniquely. If a network is localizable and embedded in plane with generic configuration, the positions of the nodes may be computed uniquely in finite time. Therefore, identifying localizable networks is an important function. If the complete information about the network is available at a single place, localizability can be tested in polynomial time. In a distributed environment, networks with trilateration orderings (popular in real applications) and wheel extensions (a specific class of localizable networks) embedded in plane can be identified by existing techniques. We propose a distributed technique which efficiently identifies a larger class of localizable networks. This class covers both trilateration and wheel extensions. In reality, exact distance is almost impossible or costly. The proposed algorithm based only on connectivity information. It requires no distance information

New Method to Calculate Electrical Forces Acting on a Sphere in an Electrorheological Fluid

We describe a method to calculate the electrical force acting on a sphere in a suspension of dielectric spheres in a host with a different dielectric constant, under the assumption that a spatially uniform electric field is applied. The method uses a spectral representation for the total electrostatic energy of the composite. The force is expressed as a certain gradient of this energy, which can be expressed in a closed analytic form rather than evaluated as a numerical derivative. The method is applicable even when both the spheres and the host have frequency-dependent dielectric functions and nonzero conductivities, provided the system is in the quasistatic regime. In principle, it includes all multipolar contributions to the force, and it can be used to calculate multi-body as well as pairwise forces. We also present several numerical examples, including host fluids with finite conductivities. The force between spheres approaches the dipole-dipole limit, as expected, at large separations, but departs drastically from that limit when the spheres are nearly in contact. The force may also change sign as a function of frequency when the host is a slightly conducting fluid.Comment: 29 pages, 8 figures, Accepted for Publication in Physical Review

Unconventional Metallic Magnetism in LaCrSb{3}

Neutron-diffraction measurements in LaCrSb{3} show a coexistence of ferromagnetic and antiferromagnetic sublattices below Tc=126 K, with ordered moments of 1.65(4) and 0.49(4) Bohr magnetons per formula unit, respectively (T=10 K), and a spin reorientation transition at ~95 K. No clear peak or step was observed in the specific heat at Tc. Coexisting localized and itinerant spins are suggested.Comment: PRL, in pres