CFD Analysis of Helicopter Wakes in Ground Effect

The paper presents CFD results for the wake of a helicopter flying a low altitude at different advance ratios. The wakes are assessed in terms of topology and velocity magnitudes. The structure of the wake near ground changes rapidly with the advance ratio and its decay appears to be faster than what is suggested by theoretical analyses. The results show clear the potential of modern CFD for use in helicopter safety and highlights the need for detailed surveys of helicopter wakes using full-scale physical experiments

Mental health and the COVID-19 pandemic: a study of medical residency training over the years

OBJECTIVES: This study aims to assess the symptoms of burnout, depression, and anxiety in Brazilian medical residents during the COVID-19 pandemic and to compare residents' beliefs and clinical practices related to COVID-19 patients among all six years of medical residency training in Brazil. METHODS: A quantitative study was conducted in April 2020 with a convenience sample of medical resident volunteers from an anonymous online survey. This investigation collected sociodemographic information and used the Oldenburg Burnout Inventory (OLBI) to measure burnout, the Patient Health Questionnaire (PHQ-9) to measure depression, and the General Anxiety Disorders (GAD-7) to measure generalized anxiety disorder. This study also developed a COVID-19 Impact Questionnaire (CIQ-19) to assess the residents' beliefs and clinical practices related to COVID-19 patients. RESULTS: Our sample comprised 3071 respondents. Depressive symptoms were the most common among second-year residents (70.5%), followed by anxiety symptoms (56.0%) and burnout (55.2%) among fourth-year residents. We also observed burnout symptoms (55.1%) among second-year residents. CONCLUSION: The COVID-19 pandemic increased the risk of mental illnesses in some years of residency. Our study could not conclude the reasons why the incidence varies among levels of physician training. Final year medical residents have avoided seeing COVID-19 patients

CFD Analysis of Helicopter Wakes in Ground Effect

The paper presents CFD results for the wake of a helicopter flying a low altitude at different advance ratios. The wakes are assessed in terms of topology and velocity magnitudes. The structure of the wake near ground changes rapidly with the advance ratio and its decay appears to be faster than what is suggested by theoretical analyses. The results show clear the potential of modern CFD for use in helicopter safety and highlights the need for detailed surveys of helicopter wakes using full-scale physical experiments

Multi-Modal Human-Machine Communication for Instructing Robot Grasping Tasks

A major challenge for the realization of intelligent robots is to supply them with cognitive abilities in order to allow ordinary users to program them easily and intuitively. One way of such programming is teaching work tasks by interactive demonstration. To make this effective and convenient for the user, the machine must be capable to establish a common focus of attention and be able to use and integrate spoken instructions, visual perceptions, and non-verbal clues like gestural commands. We report progress in building a hybrid architecture that combines statistical methods, neural networks, and finite state machines into an integrated system for instructing grasping tasks by man-machine interaction. The system combines the GRAVIS-robot for visual attention and gestural instruction with an intelligent interface for speech recognition and linguistic interpretation, and an modality fusion module to allow multi-modal task-oriented man-machine communication with respect to dextrous robot manipulation of objects.Comment: 7 pages, 8 figure

Caracterização populacional do nematoide Deladenus siricidicola, parasita da vespa-da-madeira Sirex noctilio.

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New representation of water activity based on a single solute specific constant to parameterize the hygroscopic growth of aerosols in atmospheric models

Water activity is a key factor in aerosol thermodynamics and hygroscopic growth. We introduce a new representation of water activity (<i>a</i><sub>w</sub>), which is empirically related to the solute molality (μ<sub>s</sub>) through a single solute specific constant, ν<sub><i>i</i></sub>. Our approach is widely applicable, considers the Kelvin effect and covers ideal solutions at high relative humidity (RH), including cloud condensation nuclei (CCN) activation. It also encompasses concentrated solutions with high ionic strength at low RH such as the relative humidity of deliquescence (RHD). The constant ν<sub><i>i</i></sub> can thus be used to parameterize the aerosol hygroscopic growth over a wide range of particle sizes, from nanometer nucleation mode to micrometer coarse mode particles. In contrast to other <i>a</i><sub>w</sub>-representations, our ν<sub><i>i</i></sub> factor corrects the solute molality both linearly and in exponent form <i>x · a<sup>x</sup></i>. We present four representations of our basic <i>a</i><sub>w</sub>-parameterization at different levels of complexity for different <i>a</i><sub>w</sub>-ranges, e.g. up to 0.95, 0.98 or 1. ν<sub><i>i</i></sub> is constant over the selected <i>a</i><sub>w</sub>-range, and in its most comprehensive form, the parameterization describes the entire <i>a</i><sub>w</sub> range (0–1). In this work we focus on single solute solutions. ν<sub><i>i</i></sub> can be pre-determined with a root-finding method from our water activity representation using an <i>a</i><sub>w</sub>−μ<sub>s</sub> data pair, e.g. at solute saturation using RHD and solubility measurements. Our <i>a</i><sub>w</sub> and supersaturation (Köhler-theory) results compare well with the thermodynamic reference model E-AIM for the key compounds NaCl and (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> relevant for CCN modeling and calibration studies. Envisaged applications include regional and global atmospheric chemistry and climate modeling

Viabilidade de pupas de Thelosia camina schaus coletadas em plantios de erva-mate.

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