Influence of temperature fluctuations on plasma turbulence investigations with Langmuir probes

The reliability of Langmuir probe measurements for plasma-turbulence investigations is studied on GEMR gyro-fluid simulations and compared with results from conditionally sampled I-V characteristics as well as self-emitting probe measurements in the near scrape-off layer of the tokamak ASDEX Upgrade. In this region, simulation and experiment consistently show coherent in-phase fluctuations in density, plasma potential and also in electron temperature. Ion-saturation current measurements turn out to reproduce density fluctuations quite well. Fluctuations in the floating potential, however, are strongly influenced by temperature fluctuations and, hence, are strongly distorted compared to the actual plasma potential. These results suggest that interpreting floating as plasma-potential fluctuations while disregarding temperature effects is not justified near the separatrix of hot fusion plasmas. Here, floating potential measurements lead to corrupted results on the ExB dynamics of turbulent structures in the context of, e.g., turbulent particle and momentum transport or instability identification on the basis of density-potential phase relations

Environmental risk evaluation of potential toxic elements in stream sediments – Monfortinho area (Central Portugal)

Os elementos potencialmente tóxicos (EPT) em sedimentos de corrente constituem uma importante ferramenta na avaliação do risco ambiental na influência de depósitos minerais. A região de Monfortinho está localizada na bacia hidrográfica do rio Erges, que faz fronteira com Espanha. Desde a época romana, que se conhecem evidências da exploração de ouro sedimentar nesta região do país, a qual tem vindo a desaparecer ao longo do tempo. Na avaliação da distribuição espacial de EPT selecionados – As, B, Ba, Cd, Cu, Fe, Ni, Pb, V e Zn - foram analisadas 217 amostras de sedimentos de corrente. Os sedimentos de corrente mostram uma elevada variabilidade na concentração dos EPT, podendo concluir-se que os valores mais elevados se relacionam com as mineralizações de Au na região de Monfortinho, bem como, com as de Sn-W que ocorrem nas proximidades. A maioria dos EPT apresenta um fator de contaminação moderado, embora para o Ba, Cr e B este seja elevado a muito elevado; o que se reflete num grau de contaminação moderado a elevado para a área de estudo. Na influência dos vários EPT, a maioria da área mostra um índice de resposta à toxicidade baixo, embora em 5% das amostras este seja moderado.Potentially toxic elements (PTE) of stream sediments are an important tool in environmental risk assessment associated with mineralized deposits. εonfortinho is in the watershed of the Erges river, a transboundary river with Spain. Since Roman period, there is evidence of sedimentary gold exploitation in this region, which has ceased over time. To define a spatial distribution of selected PTE - As, B, Ba, Cd, Cu, Fe, Ni, Pb, V and Zn - β17 samples of stream sediments were analysed. Stream sediments show a high PTE contents variability, suggesting that the highest values are related to the Au mineralization in εonfortinho, as well as the Sn-→ mineralization’s around the study area. Almost stream sediments show a moderate PTE contamination factor, although for Ba, Cr and B has a very high contamination; which is reflected in a moderate to high degree of contamination in the area. All the PTE contribution indicate a low toxic response index for the area, although for 5% of stream sediments indicate a moderate associated toxicity.Os autores agradecem ao δNEG (atual representante dos Serviços Geológicos de Portugal) pela cedência dos dados. Este trabalho foi desenvolvido no âmbito do ICT – Universidade do εinho (Braga).info:eu-repo/semantics/publishedVersio

Influência do substrato na formação de mudas de mangueira (Mangifera indica L.) em tubetes.

O objetivo deste estudo e avaliar a influencia do substrato na formacao de mudas de mangueira em tubetes.bitstream/CNPAT-2010/5386/1/Pa-070.pd

Rock in Rio business model – an exploratory approach

The scope of this paper is the Rock in Rio’s (RIR) Business Model (BM). The concept of creating shared value (CSV) is integrated for a better understanding of the company’s sustainability program. The main goal is the construction of RIR’s BM based on Canvas BM. The research method used was qualitative and focused on a case study. Data was collected from sixteen public interviews, with a total length of five hours, and sixteen public documents, with a total of ten pages, available in different formats (video, digital and print). Content analysis was used to process data and deliver results. The main limitation found during the research was the lack of direct information, due to untimely response to a questionnaire sent to RIR’s managers, which conditioned the enhancement of data triangulation and obtaining information related to the use of CSV in the company's sustainability program

Metal-Insulator Transition in a Disordered Two-Dimensional Electron Gas in GaAs-AlGaAs at zero Magnetic Field

A metal-insulator transition in two-dimensional electron gases at B=0 is found in Ga(Al)As heterostructures, where a high density of self-assembled InAs quantum dots is incorporated just 3 nm below the heterointerface. The transition occurs at resistances around h/e^2 and critical carrier densities of 1.2 10^11cm^-2. Effects of electron-electron interactions are expected to be rather weak in our samples, while disorder plays a crucial role.Comment: 4 pages, 3 figures, 21 reference

Prototype 9.7 m Schwarzschild-Couder telescope for the Cherenkov Telescope Array: status of the optical system

The Cherenkov Telescope Array (CTA) is an international project for a next-generation ground-based gamma ray observatory, aiming to improve on the sensitivity of current-generation experiments by an order of magnitude and provide energy coverage from 30 GeV to more than 300 TeV. The 9.7m Schwarzschild-Couder (SC) candidate medium-size telescope for CTA exploits a novel aplanatic two-mirror optical design that provides a large field of view of 8 degrees and substantially improves the off-axis performance giving better angular resolution across all of the field of view with respect to single-mirror telescopes. The realization of the SC optical design implies the challenging production of large aspherical mirrors accompanied by a submillimeter-precision custom alignment system. In this contribution we report on the status of the implementation of the optical system on a prototype 9.7 m SC telescope located at the Fred Lawrence Whipple Observatory in southern Arizona.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Busan, Korea. All CTA contributions at arXiv:1709.0348

Hydrogeochemical assessment of termal water in fractured rocks – a Portuguese case study

The thermal Fadagosa-Nisa water is located at north Alentejo (Portugal) and it is important in the economy of this region. The studied area is in a predominantly fractured granite and the water circulation is characteristic of fissured media, with a productivity of 2 L/s from a single well. Water hydrogeochemistry results revealed a mineralized water, with an electrical conductivity of 454 µS/cm and a total mineralization of 310 mg/L, neutral (pH=7.9-8.0) and a temperature of 19ºC. The thermal water has a dominant hydrogeochemical sodium-bicarbonate facies, with a fluoride (F-=9.6 mg/L) and hydrogen sulphide content (HS=15.2 mg/L), and moderate amounts of silica (SiO2=34.0 mg/L). The low nitrate (NO3-=0.1 mg/L) and sulphate (SO42-=1.6-5.2 mg/L) contents support the low vulnerability associated to the groundwater catchment. No significant seasonal changes have been found in the Fadagosa-Nisa thermal groundwater composition, suggesting a hydrogeochemical stability to the area. The regular hydrogeochemical results is in accordance to the low vulnerability obtained by the application of DRASTIC index in the Fadagosa-Nisa area.Institute of Earth Sciences (ICT), under contracts UID/GEO/04683/2013 with FCT (the Portuguese Science and Technology Foundation)info:eu-repo/semantics/publishedVersio