Two-point motional Stark effect diagnostic for Madison Symmetric Torus

A high-precision spectral motional Stark effect (MSE) diagnostic provides internal magnetic field measurements for Madison Symmetric Torus (MST) plasmas. Currently, MST uses two spatial views-on the magnetic axis and on the midminor (off-axis) radius, the latter added recently. A new analysis scheme has been developed to infer both the pitch angle and the magnitude of the magnetic field from MSE spectra. Systematic errors are reduced by using atomic data from atomic data and analysis structure in the fit. Reconstructed current density and safety factor profiles are more strongly and globally constrained with the addition of the off-axis radius measurement than with the on-axis one only

Alternative optical concept for electron cyclotron emission imaging

The implementation of advanced electron cyclotron emission imaging (ECEI) systems on tokamak experiments has revolutionized the diagnosis of magnetohydrodynamic (MHD) activities and improved our understanding of instabilities, which lead to disruptions. It is therefore desirable to have an ECEI system on the ITER tokamak. However, the large size of optical components in presently used ECEI systems have, up to now, precluded the implementation of an ECEI system on ITER. This paper describes a new optical ECEI concept that employs a single spherical mirror as the only optical component and exploits the astigmatism of such a mirror to produce an image with one-dimensional spatial resolution on the detector. Since this alternative approach would only require a thin slit as the viewing port to the plasma, it would make the implementation of an ECEI system on ITER feasible. The results obtained from proof-of-principle experiments with a 125 GHz microwave system are presented.open0

Influencia del tiempo de pausa inspiratoria sobre los parámetros de monitorización de la ventilación mecánica en un modelo de ventilación pulmonar protectora

El efecto de diferentes pausas inspiratorias ha sido estudiado exclusivamente en el ámbito del intercambio gaseoso y mayoritariamente en pacientes de cuidados intensivos. No hay datos sobre su efecto en la mecánica ventilatoria durante el período intraoperatorio de pacientes sanos sometidos a estrategias de pulmón abierto (OLA). Estudio realizado sobre 32 pacientes quirúrgicos bajo ventilación mecánica en el Hospital Universitario Virgen del Rocío. Se estandarizaron los parámetros ventilatorios (Vt 7 ml/kg, FR 13 rpm, PEEP 5 cmH20, FiO2 0’7) y se aleatorizó en base a la pausa inspiratoria inicial que se aplicó (10% vs 30%) en dos grupos. Se recogieron datos en 5 momentos: 1) Basal 2) maniobra de reclutamiento con la pausa inicial 3) cambio de una pausa inspiratoria por otra 4) maniobra de reclutamiento con la nueva pausa inspiratoria 5) vuelta a la pausa inspiratoria inicial. A igualdad de parámetros ventilatorios, una Pinsp mayor mostró menores Pplat (15.06 ± 1.77 vs 12.31 ± 1.58 cmH2O; p<0.001) y DP (10.06 ± 1.77 vs 7.31 ± 1.58 cmH2O; p<0.001) y aumentó la Crs (42.54 ± 8.91 vs 56.44 ± 13.98 ml/cmH2O; p=0.02). Al agrupar los datos en función de la Pinsp utilizada, con OLA + Pinsp 30% se obtuvieron Pplat menores (3.19 ± 2.61 cmH2O; p<0.001), PEEP más bajas (1.69 ± 2.16 cmH2O; p<0.001), menores DP (1.5 ± 1.02 cmH2O), menores PTP (1.62 ± 3.71; p=0.019) y Crs mayores (16.24 ± 8.56; p<0.001). No se encontraron diferencias en los gases sanguíneos. La combinación de estrategias de OLA con Pinsp mayores arroja ventajas con respecto a Pinsp menores, proporcionando valores más bajos de Pplat, DP, PTP y PEEP necesarias más bajas, además de mostrar valores de Crs mayores

A New Scheme for Stigmatic X-ray Imaging with Large Magnification

This paper describes a new x-ray scheme for stigmatic imaging. The scheme consists of one convex spherically bent crystal and one concave spherically bent crystal. The radii of curvature and Bragg reflecting lattice planes of the two crystals are properly matched to eliminate the astigmatism, so that the conditions for stigmatic imaging are met for a particular wavelength. The magnification is adjustable and solely a function of the two Bragg angles or angles of incidence. Although the choice of Bragg angles is constrained by the availability of crystals, this is not a severe limitation for the imaging of plasmas, since a particular wavelength can be selected from the bremsstrahlung continuum. The working principle of this imaging scheme has been verified with visible light. Further tests with x rays are planned for the near future. 2012 American Institute of Physic