From fracture to fragmentation: discrete element modeling -- Complexity of crackling noise and fragmentation phenomena revealed by discrete element simulations

Discrete element modelling (DEM) is one of the most efficient computational approaches to the fracture processes of heterogeneous materials on mesoscopic scales. From the dynamics of single crack propagation through the statistics of crack ensembles to the rapid fragmentation of materials DEM had a substantial contribution to our understanding over the past decades. Recently, the combination of DEM with other simulation techniques like Finite Element Modelling further extended the field of applicability. In this paper we briefly review the motivations and basic idea behind the DEM approach to cohesive particulate matter and then we give an overview of on-going developments and applications of the method focusing on two fields where recent success has been achieved. We discuss current challenges of this rapidly evolving field and outline possible future perspectives and debates

Higher education as a gift and as a commons

This paper takes as a starting point Lewis Hyde’s (2007, xvi) assertion that art is a gift and not a commodity: “Works of art exist simultaneously in two ‘economies’, a market economy and a gift economy. Only one of these is essential, however: a work of art can survive without a market, but where there is no gift there is no art.” I want to argue that the same claim should be made for those aspects of academic labour that refer to teaching and education. Education can survive without a market, but where there is no gift there is no education. However the gift that is part of all educational processes gets rather obscured in regimes where higher education is either a public good or a private good. In regimes of higher education as public good the gift gets obscured by the provision of a service by the state. In regimes of higher education as a private good (e.g. higher education in the UK) the gift gets even more obscured, obviously so. It is only in a third educational regime, where education is a common good (e.g. the recent rise of the free universities), that the gift character of education can properly shine. Whilst this should be celebrated, the notion of a higher education commons poses some severe challenges. The paper ends with an examination of possibilities of academic activists to rescue or even strengthen the gift-like character of education

Active and passive reduction of high order modes in the gravitational wave detector GEO 600

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