Tritium distribution analysis of Be limiter tiles from JET-ITER like wall campaigns using imaging plate technique and β-ray induced X-ray spectrometry

Tritium (T) distribution on the plasma-facing surfaces (PFSs) and inside castellation of Be limiter tiles from the JET tokamak with the ITER-like wall (ILW) was analyzed using imaging plate (IP) technique and β-ray induced X-ray spectrometry (BIXS). Regarding to PFSs, the outer poloidal limiter (OPL) showed significantly higher T concentrations than the inner wall guard limiter (IWGL) and upper dump plate (DP). The concentration of T on OPL was high at the central part. However, deuterium (D) and metallic impurities showed maximum concentration at the edges. This difference in distributions indicated different deposition and retention mechanisms between T and D. In contrast, deposition profiles of T concentrations on the castellated surfaces extended up to ∼ 5 mm into the gap, i.e. were similar to those of D and metallic impurities found by ion beam analysis.Peer reviewe

Evaluation of tritium retention in plasma facing components during JET tritium operations

An assessment of the tritium (T) inventory in plasma facing components (PFC) during JET T and deuterium-tritium (DT) operations is presented based on the most comprehensive ex situ fuel retention data set on JET PFCs from the 2015-2016 ILW3 operating period is presented. The global fuel retention is 4.19 x 10(23) D atoms, 0.19% of injected fuel. The inner divertor remains the region of highest fuel retention (46.5%). The T inventory in PFCs at the end of JET operations is calculated as 7.48 x 10(22) atoms and is informative for accountancy, clean-up efficacy and waste liability assessments. The T accumulation rate at the upper inner divertor during JET DT operations has been used to assess the requirements and frequency of operation of a new laser induced desorption diagnostic to be installed on JET for the final DT experiments in 2023.Peer reviewe

AVALIAÇÃO DAS POLÍTICAS PÚBLICAS DE CONVIVÊNCIA COM OS EFEITOS DA SECA NA ZONA RURAL DO POVOADO DE BARRA NOVA, VÁRZEA DO POÇO, BAHIA

O presente artigo faz referência ao estudo avaliativo das políticas públicas de estímulo a convivência com os efeitos da seca no semiárido tendo como base a zona rural do entorno do povoado de Barra Nova, Várzea do Poço - BA. As políticas públicas de convivência com os efeitos das secas, representadas principalmente pelas tecnologias sociais de convivência com o semiárido, têm proporcionado às famílias beneficiadas, sobretudo as mais carentes, uma melhoria nas condições de vida, capacitando-as para conviverem harmonicamente com os períodos de estiagem. Os procedimentos metodológicos foram: levantamento de referencial bibliográfico e pesquisa de campo com a realização de registros fotográficos e entrevistas com os moradores da localidade e gestores dessas polícas no local

High-fidelity patterning of AlN and ScAlN thin films with wet chemicaletching

We report on the anisotropic wet etching of sputtered AlN and Sc0.2Al0.8 N thin films. With tetramethyl ammonium hydroxide at 80 degrees C, the etch rates along the c-axis were 330 and 30 nm/s for AlN and Sc0.2Al0.8N, respectively. Although the etching was anisotropic, significant lateral etching below the mask occurred, perpendicular to the c-axis. With a 1 mu m Sc0.2Al0.8 N film, it could be up to 1800 nm. We studied the lateral etching with molybdenum, SiO2, SiNx and TiO2 masks, and found the leading cause for the lateral etching to be modification of the AlN or Sc0.2Al0.8 N surface caused by ion bombardment and surface oxidation by ambient air. The lateral etching was reduced by optimizing the mask deposition and with thermal annealing. With Sc0.2Al0.8 N, the lateral etching was reduced down to 35-220 nm depending on the mask, while with AlN, it was reduced to negligible. These results can be used for developing optimised mask deposition processes for better etch characteristics and for microfabrication of AlN and ScxAl1-xN thin-film structures.Peer reviewe

Kompetenznetz E-Learning Hessen

Mit dem Kompetenznetz e-learning-hessen.de vernetzen sich die hessischen Hochschulen mit Hilfe der Koordination und Unterstützung durch das httc und Förderung durch das Hessische Ministerium für Wissenschaft und Kunst rund um das Thema E-Learning. Dieser Beitrag beschreibt die Ziele des Netzwerks, dessen Maßnahmen und Elemente und die bisherigen Erfahrungen und seine Entwicklung seit dem Jahr 2000. Mit der abschließenden Bewertung werden Anhaltspunkte für eine erfolgreiche Vernetzung von Hochschulen und ein Ausblick auf die geplanten Aktivitäten des hessischen Netzwerkes in den nächsten Jahren gegeben. (DIPF/ Orig.

Deposition of 13C tracer and impurity elements on the divertor of Wendelstein 7-X

Carbon impurity transport and deposition were investigated in the Wendelstein 7-X stellarator by injecting isotopically labelled methane ((CH4)-C-13) into the edge plasma during the last plasma operations of its Operational Phase (OP) 1.2B experimental campaign. C-13 deposition was measured by secondary ion mass spectrometry (SIMS) on three upper divertor tiles located on the opposite side of the vessel to the(13)CH(4) inlet. The highest C-13 inventories were found as stripe-like patterns on both sides of the different strike lines. These high deposition areas were also analysed for their impurity contents and the depth profiles of the main elements in the layers. Layered deposition of different impurity elements such as Cr, Ni, Mo and B was found to reflect various events such as high metallic impurities during the OP1.2A and three boronizations carried out during OP1.2B.Peer reviewe

Ex Situ LIBS Analysis of WEST Divertor Wall Tiles after C3 Campaign

Fuel retention monitoring in tokamak walls requires the development of remote composition analysis methods such as laser-induced breakdown spectroscopy (LIBS). The present study investigates the feasibility of the LIBS method to analyse the composition and fuel retention in three samples from WEST divertor erosion marker tiles after the experimental campaign C3. The investigated samples originated from tile regions outside of strong erosion and deposition regions, where the variation of thin deposit layers is relatively small and facilitates cross-comparison between different analysis methods. The depth profiles of main constituents W, Mo and C were consistent with depth profiles determined by other composition analysis methods, such as glow-discharge optical emission spectroscopy (GDOES) and secondary ion mass spectrometry (SIMS). The average LIBS depth resolution determined from depth profiles was 100 nm/shot. The averaging of the spectra collected from multiple spots of a same sample allowed us to improve the signal-to-noise ratio, investigate the presence of fuel D and trace impurities such as O and B. In the investigated tile regions with negligible erosion and deposition, these impurities were clearly detectable during the first laser shot, while the signal decreased to noise level after a few subsequent laser shots at the same spot. LIBS investigation of samples originating from the deposition regions of tiles may further clarify LIBS’ ability to investigate trace impurities

Surface analysis of tiles and samples exposed to the first JET campaigns with the ITER-Like Wall

This paper reports on the first post-mortem analyses of tiles removed from JET after the first campaigns with the ITER-like Wall (ILW) during 2011-2 [1]. Tiles from the divertor have been analysed by the Ion Beam Analysis (IBA) techniques Rutherford Backscattering Spectroscopy (RBS) and Nuclear Reaction Analysis (NRA) and by Secondary Ion Mass Spectrometry (SIMS) to determine the amount of beryllium deposition and deuterium retention in the tiles exposed to the scrape-off layer. Films 10-20 microns thick were present at the top of Tile 1, but only very thin films (<1 micron) were found in the shadowed areas and on other divertor tiles. The total amount of Be found in the divertor following the ILW campaign was a factor of ~9 less that the material deposited in the 2007-9 carbon campaign, after allowing for the longer operations in 2007-9.Comment: 10 pages, 5 figures. This is an author-created, un-copyedited version of an article accepted for publication in Physica Scripta. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from i

Imaginarios juveniles en redes sociales, con estudiantes de tercer ciclo de los centros escolares públicos de San Salvador, 2018

Al realizar las visitas a centros escolares y entrevistas realizadas a estudiantes de tercer ciclo que fueron nuestros informantes claves, durante la investigación realizada. El recorrido se desarrolló en cinco centros escolares públicos del municipio de San Salvador que fue el campo de la investigación, con el fin de conocer la problemática y el objeto de estudio, relacionado con los ejes: “educación y sensibilización”, del Seminario de Investigación de Proceso de grado- 2018; donde se abordaran las temáticas siguientes: El Rol de los padres en el uso de las redes sociales de estudiantes de tercer ciclo, buen uso de internet y las redes sociales, aspectos positivos de las redes sociales, reforzar las buenas practicas sobre los riesgos en redes sociales, toma de decisión en el uso adecuado de las redes sociales y riesgos de las redes sociales. Conociendo con esta investigación las perspectiva en el uso adecuado de las redes sociales y los riesgos que encuentran los estudiantes, al hacer uso de las redes sociales, conociendo que los jóvenes utilizan las redes sociales de forma positiva o negativa: la investigación se realizó en un entorno educativo en cinco centros escolares públicos, así mismo se hace una propuesta para brindar alternativas de solución con la educación pretendiendo de esta forma orientar a estudiantes, padres de familias y maestros en el uso de las redes sociales, con el propósito de aportar como profesionales en trabajo social conocimientos prácticos para tercer ciclo en centros escolare