This paper is concerned with investigation of an erosion of the ITER-like divertor castellated targets of pure tungsten, lanthanum tungsten and CFC under plasma heat loads expected during the Type I ...ELMs and disruptions in ITER. These experiments were carried out on a plasma gun QSPA-T at the SRC RF TRINITI under EU/RF collaboration. The targets were exposed by series repeated plasma pulses with heat loads in the range of 0.2–2.5
MJ/m
2 and a pulse duration of 0.5
ms. The erosion value as a function of pulse number and energy density were obtained. The erosion of lanthanum tungsten started at the lower energy density as compared with pure tungsten and was mainly due to a melt layer movement and a droplets ejection. Characteristics of ejected droplets were measured. The erosion of CFC macrobrushes under ELM and disruption heat loads was determined mainly by damage of PAN-fibers.
An isotropic fine grain graphite (EK98) block has been exposed to the edge plasma in the TEXTOR tokamak and studied by Raman spectroscopy. Spectra from the net erosion area and deposition area where ...co-deposits (hard layer) were created by the tokamak discharges, are remarkably different. The spectra at the net erosion areas consist of two sharp peaks: the D-peak (≈1355
cm
−1) and the G-peak (≈1580
cm
−1). The spectra at the net deposition areas were very broad, which are similar to the Raman spectra of amorphous carbon. Fitting analyses of the Raman spectra for the net erosion area exhibit a linear relationship between the G-peak width (FWHM
G) and the peak intensity ratio (
I
D/
I
G). Comparison with the diagram derived for ion-irradiated graphite revealed that thermally unstable defects of single vacancies scarcely remained due to the power loading in this plasma exposure condition but thermally stable defects such as the dislocation dipoles could be accumulated.
The damage threshold and damage mechanisms of divertor armor materials, i.e. CFC and tungsten, were studied under the impact of ITER relevant ELM-like loads. These experiments were carried out in a ...Quasi-Stationary Plasma Accelerator applying repetitive pulses of 500
μs up to 100 cycles. CFC showed preferential erosion of the PAN fiber-bundles above 0.6
MJ/m
2 and cracking of pitch fiber-bundles. Tungsten showed cracking already at 0.2
MJ/m
2 and melting at flat surfaces above 1
MJ/m
2. Cracks in tungsten were identified as primary and secondary cracks which all propagated in the vertical direction, which was considered to be less critical. At an energy density of 1.5
MJ/m
2, the melt-layer completely covered the surface and bridged the castellation slots.
Since advanced carbon fiber composites for fusion applications, i.e., NB31, its upgraded version NB41 and DMS780, are anisotropic in terms of thermal and mechanical properties, their response under ...fusion-relevant transient heat loads is highly dependent on the orientation of the material. To understand and predict the material behavior, microstructural investigations as well as tensile tests and thermal conductivity measurements were performed in different directions (along and off the three orthotropic fiber-reinforcement axis). Furthermore, ITER-like disruption loads were applied, in the electron-beam facility JUDITH, on various carbon based materials and their thermal shock response, in terms of weight loss, was compared. Under repeated disruptions, the response of the studied materials is becoming worst if oriented differently than in the direction of highest thermal conductivity and it leads towards more homogeneous but deeper erosion zones with increased tilting angle.
Carbon fiber composites (CFCs) are the first choice as plasma facing materials for the strike points of divertor targets for future nuclear fusion devices like WENDELSTEIN 7-X and ITER. For the ...application in these facilities several potential European 3D-CFCs were compared and qualified: (1) four material batches of NB31 produced by Snecma Propulsion Solide (SNECMA); (2) NB41, SNECMA, the upgraded version of NB31; (3) N31, SNECMA, which is densified by chemical vapor infiltration (CVI) instead of a final liquid pitch infiltration characteristic for NB31; (4) a new developmental 3D-CFC produced by DUNLOP.
The characterization of the composites is comprised of thermo-physical measurements and tensile tests. The results are correlated to density and microstructure and summarized as follows: (1) NB41 provides the highest thermal conductivity in the ex-pitch direction of ∼375
W/(m
K) at room temperature; (2) all material grades are, due to their heterogeneity, characterized by a relatively large scatter of mechanical properties; (3) the different densification process for N31 in comparison to NB31 has no influence on the material properties; (4) NB41 provides in all three directions a comparably high tensile strength with an average in the ex-pitch direction of ∼220
MPa; (5) the 3D-CFC from DUNLOP is comparable to NB41 but yet does not meet the specifications in the needling direction.
RESUMEN Introducción: La glándula parótida es el sitio más común de tumores de glándulas salivales, correspondiendo al 75%-85% de éstos y al 3% de todos los tumores de cabeza y cuello. Ochenta por ...ciento de ellos corresponden a tumores benignos. Objetivos: Analizar la experiencia quirúrgica en tumores parotídeos operados en el Hospital Guillermo Grant Benavente. Material y método: Revisión de todos los pacientes con tumores parotídeos operados en el Servicio de Otorrinolaringología y Cirugía de Cabeza y Cuello, del Hospital Guillermo Grant Benavente entre enero del año 2011 y abril del año 2016. Las cirugías fueron realizadas por el mismo equipo quirúrgico. Se registraron datos demográficos, clínicos, quirúrgicos, histológicos y resultados posoperatorios. Resultados: En el periodo descrito se operó un total de 94 pacientes. 84,3% correspondieron a tumores benignos y 15,7% a tumores malignos. El 62,9% corresponde a pacientes de sexo femenino y 37,1% de sexo masculino, representando una relación de 1,69:1. La incidencia de parálisis facial transitoria fue de 16,1%, y de ellos solo un paciente mantuvo una parálisis permanente. Conclusión: Los tumores malignos representaron el 15,7%, siendo menor a lo reportado en la literatura. Se presenta una gran serie de tumores parotídeos tratados quirúrgicamente a nivel nacional, con una baja tasa de complicaciones.
Angiofibroma de fosa temporal. Reporte de un caso Fredes C, Felipe; Silva S, Gabriel; Ulloa S, Joaquín ...
Revista de otorrinolaringología y cirugía de cabeza y cuello,
06/2018, Letnik:
78, Številka:
2
Journal Article
Odprti dostop
RESUMEN El angiofibroma nasofaríngeo es el tumor benigno más frecuente de la nasofaringe, representando el 0,05% del total de las neoplasias de cabeza y cuello. Los angiofibromas en localizaciones ...distintas a la nasofaringe son entidades raras. Ellos son descritos esporádicamente en la literatura, ubicándose principalmente en el seno maxilar. En este artículo presentamos un caso de fibroangioma extranasofaríngeo localizado en fosa temporal derecha seguido de una revisión de literatura.
Angiofibroma de fosa temporal. Reporte de un caso Fredes C, Felipe; Silva S, Gabriel; Ulloa S, Joaquín ...
Revista de otorrinolaringología y cirugía de cabeza y cuello,
06/2018, Letnik:
78, Številka:
2
Journal Article
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