63 research outputs found

    A first principles simulation framework for the interactions between a Si(001) surface and a scanning probe

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    By means of total energy calculations within the framework of the local density approximation (LDA), the interactions between a silicon Si(001) surface and a scanning probe are investigated. The tip of the probe, comprising 4 Si atoms scans along the dimer lines above an asymmetric p(2 × 1) surface, at a distance where the chemical interaction between tip-surface is dominant and responsible for image resolution. At that distance, the tip causes the dimer to toggle when it scans above the lower atom of a dimer. The toggled dimers create an alternating pattern, where the immediately adja-cent neighbours of a toggled dimer remain unchanged. After the tip has fully scanned across the p(2 × 1) surface, causes the dimers to arrange in a p(2 × 2) reconstruction, reproducing the images obtained in scanning probe experiments. Our modelling methodology includes simulations that reveal the energy input required to overcome the barrier to the onset of dimer toggling. The results show that the energy input to overcome this barrier is lower for the p(2 × 1) surface than that for the p(2 × 2) or c(4 × 2) surfaces.This work has been supported by the UK Engineering and Physical Sciences Research Council (EPSRC) under contract EP/F009801/1 and Brunel University’s BRIEF award scheme. The authors would like to thank the School of Engineering and Design for purchasing our computing cluster to support research in this area. All simulations were performed on the cluster comprising 64 processors at Brunel University

    Developing Scenarios for Product Longevity and Sufficiency

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    This paper explores the narrative of peoples’ relationships with products as a window on understanding the types of innovation that may inform a culture of sufficiency. The work forms part of the 'Business as Unusual: Designing Products with Consumers in the Loop' [BaU] project, funded as part of the UK EPSRC-ESRC RECODE network (RECODE, 2016) that aims to explore the potential of re-distributed manufacturing (RdM) in a context of sustainability. This element of the project employed interviews, mapping and workshops as methods to investigate the relationship between people and products across the product lifecycle. A focus on product longevity and specifically the people-product interactions is captured in conversations around product maintenance and repair. In exploring ideas of ‘broken’ we found different characteristics of, and motivations for, repair. Mapping these and other product-people interactions across the product lifecycle indicated where current activity is, who owns such activity (i.e. organisation or individual) and where gaps in interactions occur. These issues were explored further in a workshop which grouped participants to look at products from the perspective of one of four scenarios; each scenario represented either short or long product lifespans and different types of people engagement in the design process. The findings help give shape to new scenarios for designing sufficiency-based social models of material flows

    A landscape of repair

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    This paper reports on EPSRC-funded research that explores the role of repair in creating new models of sustainable business. In the lifecycle stage of repair we explore what 'broken' means and uncover the nature of local and dispersed repair activities. This in turn allows us to better understand how the relationship between products and people can help shape new modes of consumption. Therefore, narratives of repair are collected to identify diverse people-product interactions and illustrate the different characteristics of, and motivations for, repair. The paper proposes that mapping the different product-people interactions across the product lifecycle, particularly at the stage of fragile-functionality (performance or function failure, emotional disengagement, superseded technology) is important in understanding the potential for enduring products and their repair. Building a landscape of repair creates new opportunities for manufacture and for slowing resource loops across product lifetimes, which together provide a framework for a sufficiency-based model of production and consumption
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