Roughness-induced critical phenomena in a turbulent flow

I present empirical evidence that turbulent flows are closely analogous to critical phenomena, from a reanalysis of friction factor measurements in rough pipes. The data collapse found here corresponds to Widom scaling near critical points, and implies that a full understanding of turbulence requires explicit accounting for boundary roughness

Turbulent Friction in Rough Pipes and the Energy Spectrum of the Phenomenological Theory

The classical experiments on turbulent friction in rough pipes were performed by J. Nikuradse in the 1930's. Seventy years later, they continue to defy theory. Here we model Nikuradse's experiments using the phenomenological theory of Kolmog\'orov, a theory that is widely thought to be applicable only to highly idealized flows. Our results include both the empirical scalings of Blasius and Strickler, and are otherwise in minute qualitative agreement with the experiments; they suggest that the phenomenological theory may be relevant to other flows of practical interest; and they unveil the existence of close ties between two milestones of experimental and theoretical turbulence.Comment: Accepted for publication in PRL; 4 pages, 4 figures; revised versio

Health States of Exception: unsafe non-care and the (inadvertent) production of ‘bare life’ in complex care transitions

This paper draws on the work of Giorgio Agamben to understand how the social organisation of care transitions can reduce people to their 'bare' life thereby making harmful and degrading treatment seemingly legitimate. The findings of a two-year ethnographic study show how some people experience hospital discharge as undignified, inhumane and unsafe process, expressed through their lack of involvement in care planning, delayed discharge from hospital, and poorly coordinated care. Our analysis explores how these experiences stem from the way patients are constituted as 'unknown' and 'ineligible' subjects and, in turn, how professionals become 'not responsible' for their care. In effect the person is reduce to their 'bare' life with limited value within the care system. We suggest the social productio

Soft X-ray radiation damage in EM-CCDs used for Resonant Inelastic X-ray Scattering

Advancement in synchrotron and free electron laser facilities means that X-ray beams with higher intensity than ever before are being created. The high brilliance of the X-ray beam, as well as the ability to use a range of X-ray energies, means that they can be used in a wide range of applications. One such application is Resonant Inelastic X-ray Scattering (RIXS). RIXS uses the intense and tuneable X-ray beams in order to investigate the electronic structure of materials. The photons are focused onto a sample material and the scattered X-ray beam is diffracted off a high resolution grating to disperse the X-ray energies onto a position sensitive detector. Whilst several factors affect the total system energy resolution, the performance of RIXS experiments can be limited by the spatial resolution of the detector used. Electron-Multiplying CCDs (EM-CCDs) at high gain in combination with centroiding of the photon charge cloud across several detector pixels can lead to sub-pixel spatial resolution of 2–3 μm. X-ray radiation can cause damage to CCDs through ionisation damage resulting in increases in dark current and/or a shift in flat band voltage. Understanding the effect of radiation damage on EM-CCDs is important in order to predict lifetime as well as the change in performance over time. Two CCD-97s were taken to PTB at BESSY II and irradiated with large doses of soft X-rays in order to probe the front and back surfaces of the device. The dark current was shown to decay over time with two different exponential components to it. This paper will discuss the use of EM-CCDs for readout of RIXS spectrometers, and limitations on spatial resolution, together with any limitations on instrument use which may arise from X-ray-induced radiation damage

The biosocial subject: sensor technologies and worldly sensibility

Sensor technologies are increasingly part of everyday life, embedded in buildings (movement, sound, temperature) and worn on persons (heart rate, electro-dermal activity, eye tracking). This paper presents a theoretical framework for research on computational sensor data. My approach moves away from theories of agent-centered perceptual synthesis (on behalf of a perceiving organism) and towards a more expansive understanding of the biosocial learning environment. The focus is on sensor technologies that track sensation below the bandwidth of human consciousness. I argue that there is an urgent need to reclaim this kind of biodata as part of an unequally distributed worldly sensibility, and to thereby undermine more narrow reductive readings of such data. The paper explores the biopolitical implications of recasting biodata in terms of trans-individual inhuman forces, while continuing to track the distinctive power of humans

The inclusive teacher educator: spaces for civic engagement

This paper is concerned with the teacher educator who is aspiring to be inclusive. It considers the obligations which arise within Higher Education Institutions and the extent to which these contribute to a loss of civic engagement and a lack of capacity to pursue inclusion, social justice and equity. The paper argues that this need not be the case and a reorientation for teacher educators is offered which affords teacher educators opportunities to, in Bourdieu’s (1998) terms, ‘play seriously’. This reorientation is in relation to three significant spaces – the ontological, the aesthetic and the epiphanic – and it is argued that operating within these spaces could enable new practices of inclusive teacher education to emerge

Rethinking the Ambiguities of Abstraction in the Anthropocene

The ambiguities of abstraction were at the heart of critical approaches to the problems of modernity. Abstraction, so fundamental to the modernist episteme, was seen to have alienated humanity from itself and from its entangled relations with its environment, constituting a fundamental rift between the subject and the world. This article analyses how the critique of the modernist episteme has increasingly shifted under the auspices of the Anthropocene. Rather than seeking to overcome the ambiguities of abstraction and return the human to the world, approaches that seek to affirm the Anthropocene have emphasised that modernist thought did not take abstraction far enough. Rather than abstraction being problematic for contemporary thought, abstraction is seen to be a facet of the world in its lively, partial and contingent interaction. This article is organised in three sections. The first section introduces the problematic of abstraction in the Anthropocene, highlighting that critical theory approaches tend to see the Anthropocene within a discourse of modernist critique. The second section draws out the importance of understanding the distinct mode of contemporary affirmation, which rather than seeking to return man to the world, emphasises the impossibility of finding meaning in the world. It is this inverting of critical understandings that enables abstraction to be seen positively rather than problematically. The final section expands on this point to consider how contemporary theoretical approaches articulate the transvaluation of abstraction as the guide to contemporary modes of life

Towards a Deleuzoguattarian methodology for urban design

© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. The philosophy of Gilles Deleuze and Felix Guattari (Deleuzoguattarian) is now widely thought to be apropos for today’s world. This paper proposes Deleuzoguattarian philosophy as a new methodology for urban design research and practice. First, existing methodologies in the field of urban design are examined and their strengths and limitations outlined in relation to current urban problems. A reading of Deleuzoguattarian philosophy from an urban design perspective is then provided in order to propose a new methodology for research and practice. This reading mainly concentrates on the ontology and epistemology offered by the philosophy, aspects that have been neglected in the literature. The concept of territorialization as a complementary concept to assemblage theory is highlighted in order to illustrate the characteristics of the ontology and epistemology. Finally, normative goals are discussed. It is concluded that Deleuzoguattarian philosophy is not only an ethical response to modernism but is an epistemological need

The Mediterranean Sea Regime Shift at the End of the 1980s, and Intriguing Parallelisms with Other European Basins

Background: Regime shifts are abrupt changes encompassing a multitude of physical properties and ecosystem variables, which lead to new regime conditions. Recent investigations focus on the changes in ecosystem diversity and functioning associated to such shifts. Of particular interest, because of the implication on climate drivers, are shifts that occur synchronously in separated basins. Principal Findings: In this work we analyze and review long-term records of Mediterranean ecological and hydro-climate variables and find that all point to a synchronous change in the late 1980s. A quantitative synthesis of the literature (including observed oceanic data, models and satellite analyses) shows that these years mark a major change in Mediterranean hydrographic properties, surface circulation, and deep water convection (the Eastern Mediterranean Transient). We provide novel analyses that link local, regional and basin scale hydrological properties with two major indicators of large scale climate, the North Atlantic Oscillation index and the Northern Hemisphere Temperature index, suggesting that the Mediterranean shift is part of a large scale change in the Northern Hemisphere. We provide a simplified scheme of the different effects of climate vs. temperature on pelagic ecosystems. Conclusions: Our results show that the Mediterranean Sea underwent a major change at the end of the 1980s that encompassed atmospheric, hydrological, and ecological systems, for which it can be considered a regime shift. We further provide evidence that the local hydrography is linked to the larger scale, northern hemisphere climate. These results suggest that the shifts that affected the North, Baltic, Black and Mediterranean (this work) Seas at the end of the 1980s, that have been so far only partly associated, are likely linked as part a northern hemisphere change. These findings bear wide implications for the development of climate change scenarios, as synchronous shifts may provide the key for distinguishing local (i.e., basin) anthropogenic drivers, such as eutrophication or fishing, from larger scale (hemispheric) climate drivers