Turbulence driven particle transport in Texas Helimak

We analyze the turbulence driven particle transport in Texas Helimak (K. W. Gentle and Huang He, Plasma Sci. and Technology, 10, 284 (2008)), a toroidal plasma device with one-dimensional equilibrium with magnetic curvature and shear. Alterations on the radial electric field, through an external voltage bias, change spectral plasma characteristics inducing a dominant frequency for negative bias values and a broad band frequency spectrum for positive bias values. For negative biased plasma discharges, the transport is high where the waves propagate with phase velocities near the plasma flow velocity, an indication that the transport is strongly affected by a wave particle resonant interaction. On the other hand, for positive bias the plasma has a reversed shear flow and we observe that the transport is almost zero in the shearless radial region, an evidence of a transport barrier in this region.Comment: 8 pages, 11 figure

Machine learning-driven approach for large scale decision making with the analytic hierarchy process

The Analytic Hierarchy Process (AHP) multicriteria method can be cognitively demanding for large-scale decision problems due to the requirement for the decision maker to make pairwise evaluations of all alternatives. To address this issue, this paper presents an interactive method that uses online learning to provide scalability for AHP. The proposed method involves a machine learning algorithm that learns the decision maker’s preferences through evaluations of small subsets of solutions, and guides the search for the optimal solution. The methodology was tested on four optimization problems with different surfaces to validate the results. We conducted a one factor at a time experimentation of each hyperparameter implemented, such as the number of alternatives to query the decision maker, the learner method, and the strategies for solution selection and recommendation. The results demonstrate that the model is able to learn the utility function that characterizes the decision maker in approximately 15 iterations with only a few comparisons, resulting in significant time and cognitive effort savings. The initial subset of solutions can be chosen randomly or from a cluster. The subsequent ones are recommended during the iterative process, with the best selection strategy depending on the problem type. Recommendation based solely on the smallest Euclidean or Cosine distances reveals better results on linear problems. The proposed methodology can also easily incorporate new parameters and multicriteria methods based on pairwise comparisons.This research was funded by National Funds through the FCT—Portuguese Foundation for Science and Technology, References UIDB/05256/2020 and UIDP/05256/2020

A monitoring method for the Low Voltage Power Supply modules of the ATLAS Tile Calorimeter

We present a method for testing the operational stability of Low Voltage Power Supply modules of the ATLAS Tile Calorimeter, based on a self-consistent determination of the stability criteria. The recorded voltage, current, and temperature values of each module are retrieved from the Oracle database for a long and smooth running period and their mean and RMS values over that period are determined, as well as their average recording rates, by taking into account the â??smoothingâ?? procedure which is applied during data recording to reduce data storage. The average behavior of the ensemble of all modules is determined from those time-integrated quantities and the modules are then tested one-by-one by comparing with the ensemble averages. The proposed method is tested for all Long Barrel modules operated during April of 2007

Emprego do babaçu (Orbignya phalerata) como fonte energética para caititus (Pecari tajacu).

O objetivo foi estudar o emprego de babaçu integral e torta de babaçu, como fontes energéticas substituindo parte do milho na alimentação do caititu (Pecari tajacu) em sistemas de cativeiro. No experimento-I, avaliou-se o desempenho de 12 animais, testando-se o babaçu integral em rações de mantença. No experimento-II avaliou-se o desempenho de 12 animais, testando-se a torta de babaçu em rações de terminação. Os mesmos foram abatidos para análise de carcaças. Avaliaram-se rendimento, composição, medidas, órgãos, glândulas e cortes comerciais. O Ganho diário de peso (GDP) e consumo diário de ração (CDR) dos animais que receberam babaçu integral, diminuíram quando a proporção do babaçu aumentou. Até 25% de inclusão do mesmo, obtiveram CDR satisfatório. Considerando-se a disponibilidade e custo reduzido do babaçu integral na Amazônia comparando-o ao milho, sugere-se até 25% de babaçu integral em rações de caititus em mantença. Embora não foi observada nenhuma diferença significativa (P> 0,05) dos níveis de farelo de babaçu sobre o ganho médio diário eo consumo médio diário de ração, os resultados mostram bom desempenho em 40% de torta na ração de caititus em fase de terminação. Houve uma tendência para bons GDP, consumo, rendimentos de carcaça e cortes comerciais em 40% de torta de babaçu, sugerindo-a como alternativa energética substituindo o milho em rações para caititus na fase de terminação

Calculations of three-body observables in ^8B breakup

We discuss calculations of three-body observables for the breakup of ^8B on a ^{58}Ni target at low energy using the coupled discretised continuum channels approach. Calculations of both the angular distribution of the ^7Be fragments and their energy distributions are compared with those measured at several laboratory angles. In these observables there is interference between the breakup amplitudes from different spin-parity excitations of the projectile. The resulting angle and the energy distributions reveal the importance of the higher-order continuum state couplings for an understanding of the measurements.Comment: 22 pages (postscript), accepted in Phys. Rev.