Mobile transitions : exploring synergies for urban sustainability research

Urban sustainability approaches focusing on a wide range of topics such as infrastructure and mobility, green construction and neighbourhood planning, or urban nature and green amenities have attracted scholarly interest for over three decades. Recent debates on the role of cities in climate change mitigation have triggered new attempts to conceptually and methodologically grasp the cross-sectorial and cross-level interplay of enrolled actors. Within these debates, urban and economic geographers have increasingly adopted co-evolutionary approaches such as the social studies of technology (SST or ‘transition studies’). Their plea for more spatial sensitivity of the transition approach has led to promising proposals to adapt geographic perspectives to case studies on urban sustainability. This paper advocates engagement with recent work in urban studies, specifically policy mobility, to explore conceptual and methodological synergies. It emphasises four strengths of an integrated approach: (1) a broadened understanding of innovations that emphasises not only processes of knowledge generation but also of knowledge transfer through (2) processes of learning, adaptation and mutation, (3) a relational understanding of the origin and dissemination of innovations focused on the complex nature of cities and (4) the importance of individual actors as agents of change and analytical scale that highlights social processes of innovation. The notion of urban assemblages further allows the operationalisation of both the relational embeddedness of local policies as well as their cross-sectoral actor constellations

Disrupting migration stories: reading life histories through the lens of mobility and fixity

It has been argued that the ‘mobility turn’ is overcelebratory regarding human movement across space. Yet, critical studies of mobilities have emerged that refute this, demonstrating how various forms and aspects of mobility are bound up with unequal power relations. This paper engages with debates over migration and mobility through an in-depth analysis of three life history interviews recorded in England in 2011. The subjects of the interviews are all men in their fifties and sixties of South Asian heritage, who moved to England as minors, and who, as adults, worked in factories for at least three years. The stories in all their affectivity and sensuousness disrupt standard tropes regarding migration and contribute to our understanding of the relations between mobility, fixity, ‘race’, and class. The built-in historical perspective shows how, looking back, someone who may once have migrated across international borders does not necessarily see that as the most significant moment in their life; how someone’s past moves within a nation-state may have greater significance to them than their moves into it; how people who move at one point can also be stuck, reluctantly immobile, at another; and how both the representations and materiality of mobility and fixity are imbued with, and reproduce, class inequality and racisms

Polyfluorene as a model system for space-charge-limited conduction

Ethyl-hexyl substituted polyfluorene (PF) with its high level of molecular disorder can be described very well by one-carrier space-charge-limited conduction for a discrete set of trap levels with energy $\sim$ 0.5 eV above the valence band edge. Sweeping the bias above the trap-filling limit in the as-is polymer generates a new set of exponential traps, which is clearly seen in the density of states calculations. The trapped charges in the new set of traps have very long lifetimes and can be detrapped by photoexcitation. Thermal cycling the PF film to a crystalline phase prevents creation of additional traps at higher voltages.Comment: 13 pages, 4 figures. Physical Review B (accepted, 2007

Phase field modelling of surfactants in multi-phase flow

A diffuse interface model for surfactants in multi-phase flow with three or more fluids is derived. A system of Cahn-Hilliard equations is coupled with a Navier-Stokes system and an advection-diffusion equation for the surfactant ensuring thermodynamic consistency. By an asymptotic analysis the model can be related to a moving boundary problem in the sharp interface limit, which is derived from first principles. Results from numerical simulations support the theoretical findings. The main novelties are centred around the conditions in the triple junctions where three fluids meet. Specifically the case of local chemical equilibrium with respect to the surfactant is considered, which allows for interfacial surfactant flow through the triple junctions

Imagined mobilities and the materiality of migration: the search for 'anchored lives' in post-recession Europe

The dichotomy between mobility and migration became a disputed conceptual distinction during the expansion of European Free Movement between the 1990s and early 2000s. Then, mobility literature sought to open a new chapter in the study of contemporary human lives by theorising them as ‘liquid' and suggesting movement as their universalising feature. Intra-European migrants have been increasingly characterised by their ‘mobility spirit' and therefore as legally unconstrained, driven by individualised behaviours and engaged in temporary cross-border movements. Set in the backdrop of post-recession intra-European migration, this paper explores how migrants’ mobility spirit is being negotiated with the need to anchor their lives to stable relationships and to the attainment of financial security. It draws on interviews conducted with Italian young adults in London and shows how imagined projects of temporary mobility materialize into longer-term migration experiences where the search for anchored rather than liquid lives becomes more prominent. Henceforth, the analysis challenges the typified profile of EU movers by pointing at their quest for social and financial stability and by exposing their personal vulnerabilities while making the theoretical distinction between migration and mobility less relevant