27,111 research outputs found

    Peripheral corridors: the post-metropolitan landscape of Leganes (Madrid) and Melville (Johannesburg)

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    The file attached to this record is the author's final peer reviewed versionThesis describing main arguments: This paper consists of a general history of the concept of periphery and aims to introduce the different definitions of periphery in architectural and other theories. It begins by setting out some of the difficulties encountered when attempting to define the periphery, before continuing with the three main parts to the paper. The first of these provides a general taxonomy and describes the characteristics of the periphery in architecture, based on historical general discourses; the second examines architectural discourse and typologies in more detail, developing a particular focus on the European context and thirdly it focuses in more detail on this difficulty of defining the peripheral condition in architecture theory. The architects Jonathan Woodroff, Dominic Papa and Ian Mac Burnie write (Woodroffe, J., Papa, D., and Mac Burnie, I 1994:6): “Today, it seems an almost impossible task to define a contemporary peripheral condition; and yet it is that very quality, its extreme elusiveness, that ensures its attractiveness for debate [
] In Western Europe with the exception of Britain, the notion of periphery has historically been associated with the ‘marginal’”. This quote summarises recent discourse on peripheries, where the difficulty of the theme through its elusiveness has made the discourse marginal. So it is through these marginal figures that the exploration of the theme can be carried out in order to understand its language

    Surface forces generated by the action of electric fields across liquid films

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    We explore the force generation and surface interactions arising when electric fields are applied across fluid films. Using a surface force balance (SFB) we measure directly the force between two electrodes in crossed-cylinder geometry across dielectric and electrolytic fluids. In the case of dielectric films the field between the electrodes exerts a force which can be well explained using classic expressions and with no fitting parameters. However when the electrodes are separated by a film of electrolyte, an alternating electric field induces a force which diverges substantially from the calculated static response of the electrolyte. The magnitude of the force is larger than predicted, and the interaction can switch from attractive to repulsive. Furthermore, the approach to steady state in electrolyte takes place over 10210^2 -- 10310^3~s which is very slow compared to both the charging and viscous timescales of the system. The non-trivial electrolyte response in AC electric fields, measured here directly, is likely to underlie several recent reports of unexpected and bifurcating forces driving colloids in AC fields. Our measurements suggest ways to control colloidal and soft matter using electric fields, as well as providing a direct measure of the length- and time-scales relevant in AC electrochemical and electrokinetic systems

    Magnetic Collapse of a Neutron Gas: No Magnetar Formation

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    A degenerate neutron gas in equilibrium with a background of electrons and protons in a magnetic field exerts its pressure anisotropically, having a smaller value perpendicular than along the magnetic field. For critical fields the magnetic pressure may produce the vanishing of the equatorial pressure of the neutron gas, and the outcome could be a transverse collapse of the star. This fixes a limit to the fields to be observable in stable pulsars as a function of their density. The final structure left over after the implosion might be a mixed phase of nucleons and meson (π±,0,Îș±,0\pi^{\pm,0},\kappa^{\pm,0}) condensate (a strange star also likely) or a black string, but no magnetar at all.Comment: 5 pages, 1 latex file, 1 encapsulated figure. Submitted to Physical Review Letters (24/11/2000

    Magnetic collapse of a neutron gas: Can magnetars indeed be formed

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    A relativistic degenerate neutron gas in equilibrium with a background of electrons and protons in a magnetic field exerts its pressure anisotropically, having a smaller value perpendicular than along the magnetic field. For critical fields the magnetic pressure may produce the vanishing of the equatorial pressure of the neutron gas. Taking it as a model for neutron stars, the outcome could be a transverse collapse of the star. This fixes a limit to the fields to be observable in stable neutron star pulsars as a function of their density. The final structure left over after the implosion might be a mixed phase of nucleons and meson condensate, a strange star, or a highly distorted black hole or black "cigar", but no any magnetar, if viewed as a super strongly magnetized neutron star. However, we do not exclude the possibility of a supersotrong magnetic fields arising in supernova explosions which lead directly to strange stars. In other words, if any magnetars exist, they cannot be neutron stars.Comment: 15 pages, 3 figures. European Physical Journal C in pres

    INSA scientific activities in the space astronomy area

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    Support to Astronomy operations is an important and long-lived activity within INSA. Probably the best known (and traditional) INSA activities are those related with real-time spacecraft operations: Ground station maintenance and operation (Ground station engineers and operators); spacecraft and payload real-time operation (spacecraft and instruments controllers); computing infrastructure maintenance (operators, analysts) and general site services.In this paper, we'll show a different perspective, probably not so well-known, presenting some INSA recent activities at the European Space Astronomy Centre (ESAC) and NASA Madrid Deep Space Communication Complex (MDSCC) directly related to scientific operations. Basic lines of activity involved include: Operations support for science operations; system and software support for real time systems; technical administration and IT support; R \& D activities, radioastronomy (at MDSCC and ESAC) and scientific research projects. This paper is structured as follows: first, INSA activities in two ESA cornerstone astrophysics missions, XMM-Newton and Herschel, will be outlined. Then, our activities related to Science infrastructure services, represented by the Virtual Observatory (VO) framework and the Science Archives development facilities are briefly shown. Radio Astronomy activities will be described afterwards, and finally, a few research topics in which INSA scientists are involved will be also described.Comment: 6 pages. Highlights of Spanish Astrophysics V Proceedings of the VIII Scientific Meeting of the Spanish AstronomicalSociety (SEA) held in Santander, 7-11 July, 200
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