Non-linear Simulations of MHD Instabilities in Tokamaks Including Eddy Current Effects and Perspectives for the Extension to Halo Currents

The dynamics of large scale plasma instabilities can strongly be influenced by the mutual interaction with currents flowing in conducting vessel structures. Especially eddy currents caused by time-varying magnetic perturbations and halo currents flowing directly from the plasma into the walls are important. The relevance of a resistive wall model is directly evident for Resistive Wall Modes (RWMs) or Vertical Displacement Events (VDEs). However, also the linear and non-linear properties of most other large-scale instabilities may be influenced significantly by the interaction with currents in conducting structures near the plasma. The understanding of halo currents arising during disruptions and VDEs, which are a serious concern for ITER as they may lead to strong asymmetric forces on vessel structures, could also benefit strongly from these non-linear modeling capabilities. Modeling the plasma dynamics and its interaction with wall currents requires solving the magneto-hydrodynamic (MHD) equations in realistic toroidal X-point geometry consistently coupled with a model for the vacuum region and the resistive conducting structures. With this in mind, the non-linear finite element MHD code JOREK has been coupled with the resistive wall code STARWALL, which allows to include the effects of eddy currents in 3D conducting structures in non-linear MHD simulations. This article summarizes the capabilities of the coupled JOREK-STARWALL system and presents benchmark results as well as first applications to non-linear simulations of RWMs, VDEs, disruptions triggered by massive gas injection, and Quiescent H-Mode. As an outlook, the perspectives for extending the model to halo currents are described.Comment: Proceeding paper for Theory of Fusion Plasmas (Joint Varenna-Lausanne International Workshop), Varenna, Italy (September 1-5, 2014); accepted for publication in: to Journal of Physics: Conference Serie

Peso vivo, idade de abate e características de carcaças de machos não-castrados de quatro grupos genéticos, em relação ao status nutricional, na fase de pastejo 1.

O objetivo deste trabalho foi verificar o peso vivo e idade de abate e características de carcaça de bovinos de quatro grupos genéticos (GG) que receberam zero (SR) ou 3 kg/dia de concentrado (CR), na fase de pastejo de ?Cynodon dactylon? cv. coastcross. Em três anos, 188 machos não-castrados Nelore (NE), e cruzados 1/2 Canchim + 1/2 Nelore (CN), 1/2 Angus + 1/2 Nelore (AN) e 1/2 Simental + 1/2 Nelore (SN) foram alimentados com 60% de silagem de milho e 40% de concentrado, na base seca e abatidos após atingirem terminação de 4 mm de gordura externa. As idades de abate diferiram (P0,05) para todos GG e suplementação (6,3 mm). A área de olho de lombo, em cm?2? foi maior (P0,05) para todos GG e suplementação

Self-consistent simulation of plasma scenarios for ITER using a combination of 1.5D transport codes and free-boundary equilibrium codes

Self-consistent transport simulation of ITER scenarios is a very important tool for the exploration of the operational space and for scenario optimisation. It also provides an assessment of the compatibility of developed scenarios (which include fast transient events) with machine constraints, in particular with the poloidal field (PF) coil system, heating and current drive (H&CD), fuelling and particle and energy exhaust systems. This paper discusses results of predictive modelling of all reference ITER scenarios and variants using two suite of linked transport and equilibrium codes. The first suite consisting of the 1.5D core/2D SOL code JINTRAC [1] and the free boundary equilibrium evolution code CREATE-NL [2,3], was mainly used to simulate the inductive D-T reference Scenario-2 with fusion gain Q=10 and its variants in H, D and He (including ITER scenarios with reduced current and toroidal field). The second suite of codes was used mainly for the modelling of hybrid and steady state ITER scenarios. It combines the 1.5D core transport code CRONOS [4] and the free boundary equilibrium evolution code DINA-CH [5].Comment: 23 pages, 18 figure

Resistência anti-helmíntica em ovinos na região do Médio Paranapanema, SP.

O objetivo deste trabalho foi determinar a eficácia de vários medicamentos antiparasitários contra nematóides gastrintestinais de ovinos na região do Médio Paranapanema, SP. Foi utilizado o teste de redução da contagem de ovos nas fezes (TRCOF) em cinco propriedades, com cinco princípios ativos: ivermectina, albendazol, levamisol, moxidectina e closantel, que foram comparados a um grupo controle, sem vermífugo. Foram feitas coproculturas para identificar o gênero/espécie dos parasitas. O TRCOF demonstrou que apenas em uma propriedade o levamisole apresentou 92% de eficácia, e, nesta mesma propriedade, o albendazole teve 87% de eficácia. Em outra propriedade, o closantel teve 87% de eficácia. Nas demais, nenhuma droga alcançou eficácia superior a 80%. O nematóide encontrado com maior frequência foi Haemonchus contortus, o verme mais prevalente e patogênico para os ovinos. Conclui-se que na região do Médio Paranapanema ocorre resistência anti-helmíntica múltipla do H. contortus

Avaliação da fertilidade real e da capacidade mais provável de fertilidade real de matrizes de um rebanho da Raça Nelore.

Análise de 1146 matrizes Nelore de um rebanho criado no Oeste do Estado de São Paulo.Resumo expandido

Covered call writing in a cumulative prospect theory framework

The covered call writing, which entails selling a call option on one’s underlying stock holdings, is perceived by investors as a strategy with limited risk. It is a very popular strategy used by individual, professional and institutional investors; moreover, the CBOE developed the Buy Write Index (BXM) which tracks the performance of a synthetic covered call strategy on the S&P500 Index. Previous studies analyze behavioral aspects of the covered call strategy, indicating that hedonic framing and risk aversion may explain the preference of such a strategy with respect to other designs. In this contribution, following this line of research, we extend the analysis and apply Cumulative Prospect Theory in its continuous version to the evaluation of the covered call strategy and study the effects of alternative framing

Aerodynamic investigations of ventilated brake discs.

The heat dissipation and performance of a ventilated brake disc strongly depends on the aerodynamic characteristics of the flow through the rotor passages. The aim of this investigation was to provide an improved understanding of ventilated brake rotor flow phenomena, with a view to improving heat dissipation, as well as providing a measurement data set for validation of computational fluid dynamics methods. The flow fields at the exit of four different brake rotor geometries, rotated in free air, were measured using a five-hole pressure probe and a hot-wire anemometry system. The principal measurements were taken using two-component hot-wire techniques and were used to determine mean and unsteady flow characteristics at the exit of the brake rotors. Using phase-locked data processing, it was possible to reveal the spatial and temporal flow variation within individual rotor passages. The effects of disc geometry and rotational speed on the mean flow, passage turbulence intensity, and mass flow were determined. The rotor exit jet and wake flow were clearly observed as characterized by the passage geometry as well as definite regions of high and low turbulence. The aerodynamic flow characteristics were found to be reasonably independent of rotational speed but highly dependent upon rotor geometry

Temporal and spatial dynamics of competitive parapatry in chewing lice

We synthesize observations from 1979 to 2016 of a contact zone involving two subspecies of pocket gophers (Thomomys bottae connectens and T. b. opulentus) and their respective chewing lice (Geomydoecus aurei and G. centralis) along the Rio Grande Valley in New Mexico, U.S.A., to test predictions about the dynamics of the zone. Historically, the natural flood cycle of the Rio Grande prevented contact between the two subspecies of pocket gophers. Flood control measures completed in the 1930s permitted contact, thus establishing the hybrid zone between the pocket gophers and the contact zone between their lice (without hybridization). Since that time, the pocket gopher hybrid zone has stabilized, whereas the northern chewing louse species has replaced the southern louse species at a consistent rate of similar to 150 m/year. The 0.2-0.8 width of the replacement zone has remained constant, reflecting the constant rate of chewing louse species turnover on a single gopher and within a local pocket gopher population. In contrast, the full width of the replacement zone (northernmost G. centralis to southernmost G. aurei) has increased annually. By employing a variety of metrics of the species replacement zone, we are better able to understand the dynamics of interactions between and among the chewing lice and their pocket gopher hosts. This research provides an opportunity to observe active species replacement and resulting distributional shifts in a parasitic organism in its natural setting