Tales of the Olympic city: Memory, narrative and the built environment = Historias de la ciudad olímpica: memoria, narrativa y el entorno construido

The Olympics have a greater, more profound and more pervasive impact on the urban fabric of their host cities than any other sporting or cultural event. This paper is concerned with issues of memory and remembering in Olympic host cities. After a contextual introduction, it employs a case study of the Queen Elizabeth Olympic Park (QEOP), the main event space for the London 2012 Summer Games, to supply insight into how to read the urban traces of Olympic memory. Three key themes are identified when interpreting the memories associated with the Park and its built structures, namely: treatment of the area’s displaced past, memorializing the Games, and with memory legacy. The ensuing discussion section then adopts a historiographic slant, stressing the importance of narrative and offering wider conclusions about Olympic memory and the city. = El impacto de los Juegos Olímpicos en el tejido urbano de las ciudades anfitrionas es mayor, más profundo y más generalizado que el de cualquier otro evento deportivo o cultural. Este trabajo analiza temas relacionados con la memoria y el recuerdo en las ciudades anfitrionas de los Juegos Olímpicos. Tras introducir del contexto, se utiliza un estudio de caso del Parque Olímpico Queen Elizabeth (QEOP, por sus siglas en inglés), el principal espacio de los Juegos de Verano de Londres 2012, para plantear un nuevo enfoque sobre cómo leer las huellas urbanas de la memoria olímpica. Se identifican tres temas clave al interpretar los recuerdos asociados con el Parque y sus estructuras construidas, a saber: el tratamiento del pasado desplazado del área, la conmemoración de los Juegos y el legado de la memoria. La sección de discusión adopta un enfoque historiográfico, subrayando la importancia de la narrativa y ofreciendo gran variedad de conclusiones sobre la memoria olímpica y la ciudad

Historias de la ciudad olímpica: memoria, narrativa y el entorno construido

The Olympics have a greater, more profound and more pervasive impact on the urban fabric of their host cities than any other sporting or cultural event.  This paper is concerned with issues of memory and remembering in Olympic host cities.  After a contextual introduction, it employs a case study of the Queen Elizabeth Olympic Park (QEOP), the main event space for the London 2012 Summer Games, to supply insight into how to read the urban traces of Olympic memory.  Three key themes are identified when interpreting the memories associated with the Park and its built structures, namely: treatment of the area’s displaced past, memorializing the Games, and with memory legacy.  The ensuing discussion section then adopts a historiographic slant, stressing the importance of narrative and offering wider conclusions about Olympic memory and the city.El impacto de los Juegos Olímpicos en el tejido urbano de las ciudades anfitrionas es mayor, más profundo y más generalizado que el de cualquier otro evento deportivo o cultural. Este trabajo analiza temas relacionados con la memoria y el recuerdo en las ciudades anfitrionas de los Juegos Olímpicos. Tras introducir del contexto, se utiliza un estudio de caso del Parque Olímpico Queen Elizabeth (QEOP, por sus siglas en inglés), el principal espacio de los Juegos de Verano de Londres 2012, para plantear un nuevo enfoque sobre cómo leer las huellas urbanas de la memoria olímpica. Se identifican tres temas clave al interpretar los recuerdos asociados con el Parque y sus estructuras construidas, a saber: el tratamiento del pasado desplazado del área, la conmemoración de los Juegos y el legado de la memoria. La sección de discusión adopta un enfoque historiográfico, subrayando la importancia de la narrativa y ofreciendo gran variedad de conclusiones sobre la memoria olímpica y la ciudad

Droplet size and morphology characterization for diesel sprays under atmospheric operating conditions

The shape of microscopic fuel droplets may differ from the perfect sphere, affecting their external surface area and thus the heat transfer with the surrounding gas. Hence there is a need for the characterization of droplet shapes, and the estimation of external surface area, in order to enable the development of physically accurate mathematical models for the heating and evaporation of diesel fuel sprays. We present ongoing work to automat-ically identify and reconstruct the morphology of fuel droplets, primarily focusing in this study on irregularly-shaped, partially-deformed and oscillating droplets under atmospheric conditions. We used direct imaging tech-niques based on long-working distance microscopy and ultra-high-speed video to conduct a detailed temporal investigation of droplet morphology. We applied purpose-built algorithms to extract droplet size, velocity, vol-ume and external surface area from the microscopic ultra-high-speed video frames. High resolution images of oscillating droplets and a formation of a droplet form ligament, sphericity factors, volume as well as external surface area are presented for 500 bar injection pressure in the near nozzle region (up to 0.7 mm from nozzle exit) under atmospheric conditions. We observed a range of different liquid structures, including perfectly spher-ical, non-spherical droplets and stretched ligaments. We found that large droplets and ligaments exceeding the size of the nozzle hole could be found at the end of injection. In order to estimate droplet volume and external surface area from two-dimensional droplet information, a discrete revolution of the droplet silhouette about its major centroidal axis was used. Special attention was paid to the estimation of actual errors in the prediction of volume and surface characteristics from a droplet silhouette. In addition to the estimation of droplet volume and external surface area, the actual shape reconstruction in 3D coordinates from a droplet silhouette was performed in order to enable future numerical modelling studies of real droplets

Relativistic Poynting Jets from Accretion Disks

A model is developed for relativistic Poynting jets from the inner region of a disk around a rotating black hole. The disk is initially threaded by a dipole-like magnetic field. The model is derived from the special relativistic equation for a force-free electromagnetic field. The ``head'' of the Poynting jet is found to propagate outward with a velocity which may be relativistic. The Lorentz factor of the head (Gamma) is found to be dependent on the magnetic field strength close to the black hole, B_0, the density of the external medium n_ext, and on the ratio R=r_0/r_g >1, where r_g is the gravitational radius of the black hole, and r_0 is the radius of the O-point of the initial dipole field threading the disk. For conditions pertinent to an active galactic nuclei, Gamma is approximately equal to 8 (10/R)^(1/3) (B_0/10^3 Gauss)^(1/3) (1/cm^3/n_ext)^(1/6). This model offers an explanation for the observed Lorentz factors which are of the order of 10 for the parsec-scale radio jets measured with very long baseline interferometry.Comment: 4 pages, 1 figur

Spin Precession and Avalanches

In many magnetic materials, spin dynamics at short times are dominated by precessional motion as damping is relatively small. In the limit of no damping and no thermal noise, we show that for a large enough initial instability, an avalanche can transition to an ergodic phase where the state is equivalent to one at finite temperature, often above that for ferromagnetic ordering. This dynamical nucleation phenomenon is analyzed theoretically. For small finite damping the high temperature growth front becomes spread out over a large region. The implications for real materials are discussed.Comment: 4 pages 2 figure

Seed populations for large solar particle events of cycle 23

Using high-resolution mass spectrometers on board the Advanced Composition Explorer (ACE), we surveyed the event-averaged ~0.1-60 MeV/nuc heavy ion elemental composition in 64 large solar energetic particle (LSEP) events of cycle 23. Our results show the following: (1) The rare isotope ^3He is greatly enhanced over the corona or the solar wind values in 46% of the events. (2) The Fe/O ratio decreases with increasing energy up to ~10 MeV/nuc in ~92% of the events and up to ~60 MeV/nuc in ~64% of the events. (3) Heavy ion abundances from C-Fe exhibit systematic M/g-dependent enhancements that are remarkably similar to those seen in ^3He-rich SEP events and CME-driven interplanetary (IP) shock events. Taken together, these results confirm the role of shocks in energizing particles up to ~60 MeV/nuc in the majority of large SEP events of cycle 23, but also show that the seed population is not dominated by ions originating from the ambient corona or the thermal solar wind, as previously believed. Rather, it appears that the source material for CME-associated large SEP events originates predominantly from a suprathermal population with a heavy ion enrichment pattern that is organized according to the ion's mass-per-charge ratio. These new results indicate that current LSEP models must include the routine production of this dynamic suprathermal seed population as a critical pre-cursor to the CME shock acceleration process

The Cochlear Tuning Curve

The tuning curve of the cochlea measures how large an input is required to elicit a given output level as a function of the frequency. It is a fundamental object of auditory theory, for it summarizes how to infer what a sound was on the basis of the cochlear output. A simple model is presented showing that only two elements are sufficient for establishing the cochlear tuning curve: a broadly tuned traveling wave, moving unidirectionally from high to low frequencies, and a set of mechanosensors poised at the threshold of an oscillatory (Hopf) instability. These two components suffice to generate the various frequency-response regimes which are needed for a cochlear tuning curve with a high slope

Latitude dependence of co-rotating shock acceleration

Energetic particle observations in the outer heliosphere (approx 12 A. U.) by the LECP instruments on the Voyager 1 and Voyager 2 spacecraft are discussed that show a definite latitude dependence of the number and intensity of particle enhancements produced by corotating interplanetary regions during an interval when no solar energetic particle events were observed. The particle enhancements are fewer in number and less intense at higher (approx 20 deg.) heliolatitudes. However, the similar spectral shapes of the accelerated particles at the two spacecraft indicate that the acceleration process is the same at the two latitudes, but less intense at the higher latitude