120 research outputs found

    Ultracool White Dwarfs and the Age of the Galactic Disc

    Get PDF
    We present parallax observations and a detailed model atmosphere analysis of 54 cool and ultracool (Teff \u3c 4000 K) white dwarfs (WDs) in the solar neighbourhood. For the first time, a large number of cool and ultracool WDs have distance and tangential velocities measurements available. Our targets have distances ranging from 21 pc to \u3e100 pc, and include five stars within 30 pc. Contrary to expectations, all but two of them have tangential velocities smaller than 150 km s−1 thus suggesting Galactic disc membership. The oldest WDs in this sample have WD cooling ages of 10 Gyr, providing a firm lower limit to the age of the thick disc population. Many of our targets have uncharacteristically large radii, indicating that they are low mass WDs. It appears that we have detected the brighter population of cool and ultracool WDs near the Sun. The fainter population of ultracool CO-core WDs remain to be discovered in large numbers. The Large Synoptic Survey Telescope should find these elusive, more massive ultracool WDs in the solar neighbourhood

    Spin recovery in the 25nm gate length InGaAs field effect transistore

    Get PDF
    We augmented an ensemble Monte-Carlo semiconductor device simulator [3] to incorporate electron spin degrees of freedom using a Bloch equation model to investigate the feasibility of spintronic devices. Results are presented for the steady state polarization and polarization decay due to scattering and spin orbit coupling for a III-V MOSFET device as a function of gate voltages, injection polarization and strain

    Preferred EAC initiation sites in 7xxx aluminum

    Get PDF
    Please click Additional Files below to see the full abstrac

    Spin recovery in the 25nm gate length InGaAs field effect transistore

    Get PDF
    We augmented an ensemble Monte-Carlo semiconductor device simulator [3] to incorporate electron spin degrees of freedom using a Bloch equation model to investigate the feasibility of spintronic devices. Results are presented for the steady state polarization and polarization decay due to scattering and spin orbit coupling for a III-V MOSFET device as a function of gate voltages, injection polarization and strain

    Getting nowhere fast: a teleological conception of socio-technical acceleration

    Get PDF
    It has been frequently recognized that the perceived acceleration of life that has been experienced from the Industrial Revolution onward is engendered, at least in part, by an understanding of speed as an end in itself. There is no equilibrium to be reached – no perfect speed – and as such, social processes are increasingly driven not by rational ends, but by an indeterminate demand for acceleration that both defines and restricts the decisional possibilities of actors. In Aristotelian terms, this is a final cause – i.e. a teleology – of speed: it is not a defined end-point, but rather, a purposive aim that predicates the emergence of possibilities. By tracing this notion of telos from its beginnings in ancient Greece, through the ur-empiricism of Francis Bacon, and then to our present epoch, this paper seeks to tentatively examine the way in which such a teleology can be theoretically divorced from the idea of historical progress, arguing that the former is premised upon an untenable ontological privileging of becoming

    The democratic interface: technology, political organization, and diverging patterns of electoral representation

    Get PDF
    Democracies are experiencing historic disruptions affecting how people engage with core institutions such as the press, civil society organizations, parties, and elections. These processes of citizen interaction with institutions operate as a democratic interface shaping self-government and the quality of public life. The electoral dimension of the interface is important, as its operation can affect all others. This analysis explores a growing left-right imbalance in the electoral connection between citizens, parties, elections, and government. This imbalance is due, in part, to divergent left-right preferences for political engagement, organization, and communication. Support on the right for clearer social rules and simpler moral, racial and nationalist agendas are compatible with hierarchical, leader-centered party organizations that compete more effectively in elections. Parties on the left currently face greater challenges engaging citizens due to the popular meta-ideology of diversity and inclusiveness and demands for direct or deliberative democracy. What we term connective parties are developing technologies to perform core organizational functions, and some have achieved electoral success. However, when connective parties on the left try to develop shared authority processes, online and offline, they face significant challenges competing with more conventionally organized parties on the right

    Liquid networks and the metaphysics of flux: ontologies of flow in an age of speed and mobility

    Get PDF
    It is common for social theorists to utilize the metaphors of ‘flow’, ‘fluidity’, and ‘liquidity’ in order to substantiate the ways in which speed and mobility form the basis for a new kind of information or network society. Yet rarely have these concepts been sufficiently theorized in order to establish their relevance or appropriateness. This article contends that the notion of flow as utilized in social theory is profoundly metaphysical in nature, and needs to be judged as such. Beginning with a discussion of the accelerating timescape that characterizes the network society, it will then move on to examine three main issues with this ‘metaphysics of flux’. First, that the concept of flows unjustly privileges the process of becoming and, as a result, is unable to account for the materiality, substantiality, and agency of the objects being mobilized, and the contingency of their mediation. Second, that it posits the accelerating tendencies of capital as an ontological inevitability, thus discounting resistance to such forces. Finally, that it ignores the human faculty for reason and speculative thought in developing alternative means of political praxis. The solution, it will be argued, is not to abandon metaphysical accounts of the network society, but rather to challenge those accounts that, in exhibiting a crude empiricism, work to justify the status quo
    • …
    corecore