713 research outputs found
Procedimento prático para elaboração de uma tabela de produção.
bitstream/CNPF-2009-09/43533/1/Doc165.pd
Orienting versus inhibition in the concealed information test: different cognitive processes drive different physiological measures
The Concealed Information Test (CIT) provides a valid tool for psychophysiological detection of concealed knowledge. However, its precise theoretical underpinnings remain a matter of debate. The differential physiological responses elicited by concealed, relevant items, relative to control items, were traditionally explained as reflecting an orienting response (OR). According to an alternative account, these responses reflect attempts to inhibit arousal. The present study examined whether and to what extent CIT detection efficiency is affected by instructions aimed at manipulating arousal inhibition (AI). One hundred and forty-eight undergraduate students completed a CIT, while electrodermal, cardiac, and respiratory measures were recorded. Half of the participants were requested to imagine that they are suspected of committing a crime and were motivated to avoid detection (presumably eliciting both OR and AI), while the other half were requested to imagine that they are witnesses of a crime and were motivated to be detected (presumably eliciting OR only). All participants were further requested to remain silent throughout the test. In both conditions, concealed items led to a similar increase in skin conductance as compared to the control items. However, the typically observed heart rate deceleration and respiratory suppression were found in suspects, but not in witnesses. These data imply that different mechanisms drive the responding of different psychophysiological measures used in the CIT, with skin conductance reflecting OR, and heart rate and respiration primarily reflecting AI
Influence of Heat Transfer and Material Temperature on Combustion Instabilities in a Swirl Burner
The current work focuses on the large eddy simulation (LES) of combustion instability in a laboratory-scale swirl burner. Air and fuel are injected at ambient conditions. Heat conduction from the combustion chamber to the plenums results in a preheating of the air and fuel flows above ambient conditions. The paper compares two computations: In the first computation, the temperature of the injected reactants is 300 K (equivalent to the experiment) and the combustor walls are treated as adiabatic. The frequency of the unstable mode ( 635 Hz) deviates significantly from the measured frequency ( 750 Hz). In the second computation, the preheating effect observed in the experiment and the heat losses at the combustion chamber walls are taken into account. The frequency ( 725 Hz) of the unstable mode agrees well with the experiment. These results illustrate the impor- tance of accounting for heat transfer/losses when applying LES for the prediction of com- bustion instabilities. Uncertainties caused by unsuitable modeling strategies when using computational fluid dynamics for the prediction of combustion instabilities can lead to an improper design of passive control methods (such as Helmholtz resonators) as these are often only effective in a limited frequency range
Uso do dendrograma de manejo de densidade: uma aplicação prática com Hovenia dulcis Thunberg.
O objetivo principal deste trabalho é fazer uma aplicação prática dos dendrogramas de manejo de densidade em uma população de Hovenía dulcís localizada na região central do estado do Rio Grande do Sul. Para tanto, foram utilizados dados de um povoamento de Hovenia dutcis de aproximadamente 1,3 hectares com 25 anos de idade, localizado em área da Fundação de Pesquisa Agropecuária (FEPAGRO). O dendrograma de densidade utilizado para a simulação das intervenções foi elaborado por Selle (2009), para o local e espécie. Estabeleceu-se que a melhor forma de conduzir o povoamento é com a aplicação de duas intervenções silviculturais, sendo uma aplicada imediatamente e outra, quando o diâmetro da árvore de área basal média atingir 27 em. No primeiro desbaste devem ser retiradas 36,6% e no segundo 33,3% das árvores, correspondendo a 33,6 e 45,6% da área basal, respectivamente
High Performance Algorithms for Counting Collisions and Pairwise Interactions
The problem of counting collisions or interactions is common in areas as
computer graphics and scientific simulations. Since it is a major bottleneck in
applications of these areas, a lot of research has been carried out on such
subject, mainly focused on techniques that allow calculations to be performed
within pruned sets of objects. This paper focuses on how interaction
calculation (such as collisions) within these sets can be done more efficiently
than existing approaches. Two algorithms are proposed: a sequential algorithm
that has linear complexity at the cost of high memory usage; and a parallel
algorithm, mathematically proved to be correct, that manages to use GPU
resources more efficiently than existing approaches. The proposed and existing
algorithms were implemented, and experiments show a speedup of 21.7 for the
sequential algorithm (on small problem size), and 1.12 for the parallel
proposal (large problem size). By improving interaction calculation, this work
contributes to research areas that promote interconnection in the modern world,
such as computer graphics and robotics.Comment: Accepted in ICCS 2019 and published in Springer's LNCS series.
Supplementary content at https://mjsaldanha.com/articles/1-hpc-ssp
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