Examinando por Autor "Moreno, José"

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  • Miniatura
    Ítem
    Electromagnetic burst measurement system based on low cost UHF dipole antenna
    (Energies, 2017-09) Escalona, Ismael; Avaria, Gonzalo; Díaz, Marcos; Ardila-Rey, Jorge; Moreno, José; Pavez, Cristian; Soto, Leopoldo
    Non-linear high-power devices produce electromagnetic noise (EMN) sources of great intensity that can disrupt and damage the surrounding electrical equipment and devices. This radiative phenomenon is very common at facilities where pulsed power generators are required, particularly those that are needed to produce dense transient plasma experiments. These conditions are found at the Chilean Nuclear Energy Commission (CCHEN), due to the presence of pulsed power generators that switch large currents (kA-MA) in short times (10-100 ns). In order to characterize and establish conditions to mitigate the effects of the EMN on nearby devices, a measurement system based on an ultra-high frequency (UHF) dipole antenna was developed. We evaluated the system measuring the EMN emanated from a plasma focus device, the PF-400J. Measurements at the place indicated broadband and intense electric fields that can couple to nearby cables and equipment (10-300 MHz bandwidth, up to 350 V/MHz spectral intensity, 100 V coupled voltage). Based on these measurements a compact and simple protection system was designed, built and tested, capable of effectively mitigating the high levels of EMN. The proper EMN impact mitigation indicates the correct operation of the suggested system. The developed system can be of interest to the energy community by facilitating EMN measurement produced by arc discharges. © 2017 by the authors.
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    Ítem
    Kappa distribution from particle correlations in nonequilibrium, steady-state plasmas
    (American Physical Society, 2023-12) Davis, Sergio; Avaria, Gonzalo; Bora, Biswajit; Jain, Jalaj; Moreno, José; Pavez, Cristian; Soto, Leopoldo
    Kappa-distributed velocities in plasmas are common in a wide variety of settings, from low-density to high-density plasmas. To date, they have been found mainly in space plasmas, but are recently being considered also in the modeling of laboratory plasmas. Despite being routinely employed, the origin of the kappa distribution remains, to this day, unclear. For instance, deviations from the Maxwell-Boltzmann distribution are sometimes regarded as a signature of the nonadditivity of the thermodynamic entropy, although there are alternative frameworks such as superstatistics where such an assumption is not needed. In this work we recover the kappa distribution for particle velocities from the formalism of nonequilibrium steady-states, assuming only a single requirement on the dependence between the kinetic energy of a test particle and that of its immediate environment. Our results go beyond the standard derivation based on superstatistics, as we do not require any assumption about the existence of temperature or its statistical distribution, instead obtaining them from the requirement on kinetic energies. All of this suggests that this family of distributions may be more common than usually assumed, widening its domain of application in particular to the description of plasmas from fusion experiments. Furthermore, we show that a description of kappa-distributed plasma is simpler in terms of features of the superstatistical inverse temperature distribution rather than the traditional parameters κ and the thermal velocity vth.
  • Miniatura
    Ítem
    Teoría y construcción de un Portfolio óptimo
    (Universidad Andrés Bello, 2003) Zamora, Ximena; Moreno, José; Teuber, Alejandro; Escuela de Ingeniería de Ejecución en Administración
    La aplicación de esta teoría en el mercado de valores con los nuevos instrumentos financieros a abierto una gran posibilidad de inversión para los inversionistas chilenos los cuales deberán decidir entre las diferentes opciones de combinaciones de riesgo y rendimiento, maximizar el rendimiento esperado a un cierto nivel de riesgo o minimizar el riesgo a un nivel esperado de rendimiento. Esto nos llevó a formularnos ciertas preguntas acerca de la validez de esta teoría en el mercado internacional y ver la posibilidad de aplicarla en otra área de interés, la bancaria.