103 research outputs found

    Towards an analytical framework of science communication models

    Get PDF
    This chapter reviews the discussion in science communication circles of models for public communication of science and technology (PCST). It questions the claim that there has been a large-scale shift from a ‘deficit model’ of communication to a ‘dialogue model’, and it demonstrates the survival of the deficit model along with the ambiguities of that model. Similar discussions in related fields of communication, including the critique of dialogue, are briefly sketched. Outlining the complex circumstances governing approaches to PCST, the author argues that communications models often perceived to be opposed can, in fact, coexist when the choices are made explicit. To aid this process, the author proposes an analytical framework of communication models based on deficit, dialogue and participation, including variations on each

    Shaping pedestrian movement through playful interventions in security planning: what do field surveys suggest?

    Get PDF
    © 2015 Taylor & Francis The control and shaping of pedestrian movement recurs as an aspect of security planning for crowded spaces. Using the concepts of triangulation, performance and flow, this paper presents a series of experiments designed to shape pedestrian movement patterns in public spaces in different spatial and operation contexts, by eliciting noticeable behaviours and disrupting routine use of space. The hypothesis investigated is that playful, non-obstructive interventions foster a positive social experience yet can be used to shape pedestrian movement. The interventions examined were around the themes of floor marking and mirrors. Analysis demonstrated that the interventions were able to create zones of attraction and exclusion, engage people’s curiosity and elicit playful actions. Habituation, goal-directed behaviour and the influence of increased cognitive load at personal level were all important factors responsible for reducing the level of engagement with an intervention. The results suggest that increased understanding between environmental and interpersonal stimuli and behavioural responses can provide guidance in using socially acceptable design interventions to influence use of space in different operational contexts, contributing to sustainable security

    Operating a full tungsten actively cooled tokamak: overview of WEST first phase of operation

    Get PDF
    WEST is an MA class superconducting, actively cooled, full tungsten (W) tokamak, designed to operate in long pulses up to 1000 s. In support of ITER operation and DEMO conceptual activities, key missions of WEST are: (i) qualification of high heat flux plasma-facing components in integrating both technological and physics aspects in relevant heat and particle exhaust conditions, particularly for the tungsten monoblocks foreseen in ITER divertor; (ii) integrated steady-state operation at high confinement, with a focus on power exhaust issues. During the phase 1 of operation (2017–2020), a set of actively cooled ITER-grade plasma facing unit prototypes was integrated into the inertially cooled W coated startup lower divertor. Up to 8.8 MW of RF power has been coupled to the plasma and divertor heat flux of up to 6 MW m−2 were reached. Long pulse operation was started, using the upper actively cooled divertor, with a discharge of about 1 min achieved. This paper gives an overview of the results achieved in phase 1. Perspectives for phase 2, operating with the full capability of the device with the complete ITER-grade actively cooled lower divertor, are also described

    Overview of JET results for optimising ITER operation

    Get PDF
    The JET 2019–2020 scientific and technological programme exploited the results of years of concerted scientific and engineering work, including the ITER-like wall (ILW: Be wall and W divertor) installed in 2010, improved diagnostic capabilities now fully available, a major neutral beam injection upgrade providing record power in 2019–2020, and tested the technical and procedural preparation for safe operation with tritium. Research along three complementary axes yielded a wealth of new results. Firstly, the JET plasma programme delivered scenarios suitable for high fusion power and alpha particle (α) physics in the coming D–T campaign (DTE2), with record sustained neutron rates, as well as plasmas for clarifying the impact of isotope mass on plasma core, edge and plasma-wall interactions, and for ITER pre-fusion power operation. The efficacy of the newly installed shattered pellet injector for mitigating disruption forces and runaway electrons was demonstrated. Secondly, research on the consequences of long-term exposure to JET-ILW plasma was completed, with emphasis on wall damage and fuel retention, and with analyses of wall materials and dust particles that will help validate assumptions and codes for design and operation of ITER and DEMO. Thirdly, the nuclear technology programme aiming to deliver maximum technological return from operations in D, T and D–T benefited from the highest D–D neutron yield in years, securing results for validating radiation transport and activation codes, and nuclear data for ITER

    Global scaling of the heat transport in fusion plasmas

    Get PDF

    Investigation into the formation of the scrape-off layer density shoulder in JET ITER-like wall L-mode and H-mode plasmas

    Get PDF
    The low temperature boundary layer plasma (Scrape-Off-Layer or SOL) between the hot core and the surrounding vessel determines the level of power-loading, erosion and implantation of material surfaces, and thus the viability of tokamak-based fusion as an energy source. This study explores mechanisms affecting the formation of flattened density profiles, so-called ‘density shoulders’, in the low-field side (LFS) SOL, which modify ion and neutral fluxes to surfaces – and subsequent erosion. There is evidence against local enhancement of ionization inducing shoulder formation. We find that increases in SOL parallel resistivity, Λdiv (=[L||νei Ωi ]/cs Ωe), postulated to lead to shoulder growth through changes in SOL turbulence characteristics, correlates with increases in upstream SOL shoulder amplitude, As only under a subset of conditions (D2-fuelled L-mode density scans with outer strike point on the horizontal target). Λdiv fails to correlate with As for cases of N2 seeding or during sweeping of the strike point across the horizontal target. The limited correlation of Λdiv with As was also found for H-mode discharges. Thus, while Λdiv above a threshold of ~1 may be necessary for shoulder formation and/or growth, another shoulder mechanism is required. More significantly we find that in contrast to parallel resistivity, outer divertor recycling as quantified by the total outer divertor Balmer Dα emission, I-Dα, does scale with shoulder amplitude where Λdiv does and even where Λdiv fails. Divertor recycling could lead to SOL density shoulder formation through: a) reducing the parallel to the field flow (loss) of ions out of the SOL to the divertor; and b) changes in radial electric fields which lead to ExB poloidal flows as well as potentially affecting the SOL turbulence birth characteristics. Thus changes in divertor recycling may be the sole process in bringing about SOL density shoulders or in tandem with parallel resistivity

    Neutral pathways and heat flux widths in vertical- and horizontal-target EDGE2D-EIRENE simulations of JET

    Get PDF
    This paper further analyses the EDGE2D-EIRENE simulations presented by Chankin et al (2017 Nucl. Mater. Energy 12 273), of L-mode JET plasmas in vertical-vertical (VV) and Vertical-horizontal (VH) divertor configurations. As expected, the simulated outer divertor ionisation source peaks near the separatrix in VV and radially further out in VH. We identify the reflections of recycled neutrals from lower divertor tiles as the primary mechanism by which ionisation is concentrated on the outer divertor separatrix in the VV configuration. These lower tile reflection pathways (of neutrals from the outer divertor, and to an even greater extent from the inner divertor) dominate the outer divertor separatrix ionisation. In contrast, the lower-tile-reflection pathways are much weaker in the VH simulation and its outer divertor ionisation is dominated by neutrals which do not reflect from any surfaces. Interestingly, these differences in neutral pathways give rise to strong differences in the heat flux density width λq at the outer divertor entrance: λq = 3.2 mm in VH compared to λq = 11.8 mm in VV. In VH, a narrow channel exists in the near scrape-off-layer (SOL) where the convected heat flux, driven by strong Er × B flow and thermoelectric current, dominates over the conducted heat flux. The width of this channel sets λq and is determined by the radial distance between the separatrix and the ionisation peak in the outer divertor

    Observations and modelling of ion cyclotron emission observed in JET plasmas using a sub-harmonic arc detection system during ion cyclotron resonance heating

    Get PDF
    Peer reviewe

    Overview of the JET results in support to ITER

    Get PDF

    Risk and the social construction of ‘Gulf War Syndrome’

    No full text
    Fifteen years since the events that are held by some to have caused it, Gulf War Syndrome continues to exercise the mind and energies of numerous researchers across the world, as well as those who purport to be its victims and their advocates in the media, law and politics. But it may be that the search for a scientific or medical solution to this issue was misguided in the first place, for Gulf War Syndrome, if there is such an entity, appears to have much in common with other ‘illnesses of modernity’, whose roots are more socially and culturally driven than what doctors would conventionally consider to be diseases. The reasons for this are complex, but derive from our contemporary proclivity to understand humanity as being frail and vulnerable in an age marked by an exaggerated perception of risk and a growing use of the ‘politics of fear’. It is the breakdown of social solidarities across the twentieth century that has facilitated this process. Unfortunately, as this paper explores, our inability to understand the social origins of self-hood and illness, combined with a growing cynicism towards all sources of authority, whether political, scientific, medical or corporate, has produced a powerful demand for blame and retribution deriving from a resolute few who continue to oppose all of the evidence raised against them. Sadly, this analysis suggests that Gulf War Syndrome is likely to prove only one of numerous such instances that are likely to emerge over the coming years
    corecore