10,301 research outputs found

    The effects of aeroelastic deformation on the unaugmented stopped-rotor dynamics of an X-Wing aircraft

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    A new design concept in the development of VTOL aircraft with high forward flight speed capability is that of the X-Wing, a stiff, bearingless helicopter rotor system which can be stopped in flight and the blades used as two forward-swept and two aft-swept wings. Because of the usual configuration in the fixed-wing mode, there is a high potential for aeroelastic divergence or flutter and coupling of blade vibration modes with rigid-body modes. An aeroelastic stability analysis of an X-Wing configuration aircraft was undertaken to determine if these problems could exist. This paper reports on the results of dynamic stability analyses in the lateral and longitudinal directions including the vehicle rigid-body and flexible modes. A static aeroelastic analysis using the normal vibration mode equations of motion was performed to determine the cause of a loss of longitudinal static margin with increasing airspeed. This loss of static margin was found to be due to aeroelastic washin of the forward-swept blades and washout of the aft-swept blades moving the aircraft aerodynamic center forward of the center of gravity. This phenomenon is likely to be generic to X-Wing aircraft

    Large angle magnetization dynamics measured by time-resolved ferromagnetic resonance

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    A time-resolved ferromagnetic resonance technique was used to investigate the magnetization dynamics of a 10 nm thin Permalloy film. The experiment consisted of a sequence of magnetic field pulses at a repetition rate equal to the magnetic systems resonance frequency. We compared data obtained by this technique with conventional pulsed inductive microwave magnetometry. The results for damping and frequency response obtained by these two different methods coincide in the limit of a small angle excitation. However, when applying large amplitude field pulses, the magnetization had a non-linear response. We speculate that one possible cause of the nonlinearity is related to self-amplification of incoherence, known as the Suhl instabilities.Comment: 23 pages, 8 figures, submitted to PR

    Integrated process of images and acceleration measurements for damage detection

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    The use of mobile robots and UAV to catch unthinkable images together with on-site global automated acceleration measurements easy achievable by wireless sensors, able of remote data transfer, have strongly enhanced the capability of defect and damage evaluation in bridges. A sequential procedure is, here, proposed for damage monitoring and bridge condition assessment based on both: digital image processing for survey and defect evaluation and structural identification based on acceleration measurements. A steel bridge has been simultaneously inspected by UAV to acquire images using visible light, or infrared radiation, and monitored through a wireless sensor network (WSN) measuring structural vibrations. First, image processing has been used to construct a geometrical model and to quantify corrosion extension. Then, the consistent structural model has been updated based on the modal quantities identified using the acceleration measurements acquired by the deployed WSN. © 2017 The Authors. Published by Elsevier Ltd

    NOVO REGISTRO DE FABACEAE (CAESALPINIOIDEAE) PARA O BRASIL: Dimorphandra davisii SPRAGUE & SANDWITH

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    The study presents the first occurrence of Dimorphandra davisii Sprague & Sandwith from Brazil, a species previously known only in Guyana and Venezuela. After examining the INPA and NY herbarium collections, it was verified that the species was collected in 1986 and occurs in the municipality of Presidente Figueiredo, in the state of Amazonas, but never registered for the Brazilian flora. The record of the species increases the floristic data of the Brazilian Amazon and contributes to the better knowledge of Dimorphandra in Brazil.Keywords: Caesalpinieae; Distribution of species; Amazon Rainforest; Taxonomy.O estudo apresenta a primeira ocorrência de Dimorphandra davisii Sprague et Sandwith do Brasil, uma espécie conhecida apenas na Guiana e Venezuela. Depois de examinar as coleções dos herbários INPA e NY, verificou-se que a espécie foi coletada em 1986 e ocorre no município de Presidente Figueiredo, no estado do Amazonas, mas nunca registrada para a flora brasileira. O registro da espécie aumenta os dados florísticos da Amazônia brasileira e contribui para o melhor conhecimento de Dimorphandra no Brasil.Palavras-chave: Caesalpinieae, Distribuição de espécies, Floresta Amazônica, Taxonomia

    Multi-reference approach to the calculation of photoelectron spectra including spin-orbit coupling

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    X-ray photoelectron spectra provide a wealth of information on the electronic structure. The extraction of molecular details requires adequate theoretical methods, which in case of transition metal complexes has to account for effects due to the multi-configurational and spin-mixed nature of the many-electron wave function. Here, the Restricted Active Space Self-Consistent Field method including spin-orbit coupling is used to cope with this challenge and to calculate valence and core photoelectron spectra. The intensities are estimated within the frameworks of the Dyson orbital formalism and the sudden approximation. Thereby, we utilize an efficient computational algorithm that is based on a biorthonormal basis transformation. The approach is applied to the valence photoionization of the gas phase water molecule and to the core ionization spectrum of the [Fe(H2O)6]2+\text{[Fe(H}_2\text{O)}_6\text{]}^{2+} complex. The results show good agreement with the experimental data obtained in this work, whereas the sudden approximation demonstrates distinct deviations from experiments

    The efficacy of a compassion-focused therapy–based intervention in reducing psychopathic traits and disruptive behavior: a clinical case study with a juvenile detainee

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    Conduct disorder (CD) is the most diagnosed psychopathological disorder in juvenile detainees. The presence of a CD diagnosis, especially when associated with psychopathic traits, contributes to a poor prognosis, high recidivism rates, and low responsivity to treatment in these youth. Although group intervention programs have proven to be effective in decreasing antisocial behavior, studies testing their efficacy in reducing psychopathic traits are scarce and limited. Moreover, there is a lack of research focused on the efficacy of individual treatment approaches specifically designed to reduce psychopathic traits and disruptive behavior in juvenile detainees. Compassion-focused therapy (CFT) shows promising results in the treatment of several psychopathological disorders. Besides, there is some theoretical support to consider CFT a suitable approach to treating juvenile detainees. However, there are no treatment programs based on CFT that are designed to target psychopathic traits and disruptive behavior in these youth. Consequently, treatment outcome research in this area is absent. This clinical case study presents the treatment of a juvenile detainee with CD, a high psychopathic profile, and a very high risk for criminal recidivism using the PSYCHOPATHY.COMP program (a 20-session individual CFT program), which was specially designed to reduce psychopathic traits and disruptive behavior. The treatment outcome data revealed a significant reduction in psychopathic traits and disruptive behavior. The treatment gains were maintained and/or increased over time (3 months after program completion). This clinical case study demonstrates the feasibility and efficacy of the PSYCHOPATHY.COMP program in reducing psychopathic traits and disruptive behavior in a juvenile detainee.This research has been supported by the first author PhD Grant (SFRH/BD/99795/2014), sponsored by the Portuguese Foundation for Science and Technology (FCT). This work was also financed by FEDER—European Social Fund—through the COMPETE 2020-Operational Program for Competitiveness and Internationalization (POCI), and by Portuguese funds through FCT in the framework of the project POCI-01-0145-FEDER-016724

    Short versus long silver nanowires: a comparison of in vivo pulmonary effects post instillation.

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    BackgroundSilver nanowires (Ag NWs) are increasingly being used to produce touchscreens for smart phones and computers. When applied in a thin film over a plastic substrate, Ag NWs create a transparent, highly-conductive network of fibers enabling the touch interface between consumers and their electronics. Large-scale application methods utilize techniques whereby Ag NW suspensions are deposited onto substrates via droplets. Aerosolized droplets increase risk of occupational Ag NW exposure. Currently, there are few published studies on Ag NW exposure-related health effects. Concerns have risen about the potential for greater toxicity from exposure to high-aspect ratio nanomaterials compared to their non-fibrous counterparts. This study examines whether Ag NWs of varying lengths affect biological responses and silver distribution within the lungs at different time-points.MethodsTwo different sizes of Ag NWs (2 μm [S-Ag NWs] and 20 μm [L-Ag NWs]) were tested. Male, Sprague-Dawley rats were intratracheally instilled with Ag NWs (0, 0.1, 0.5, or 1.0 mg/kg). Broncho-alveolar lavage fluid (BALF) and lung tissues were obtained at 1, 7, and 21 days post exposure for analysis of BAL total cells, cell differentials, and total protein as well as tissue pathology and silver distribution.Results and conclusionsThe two highest doses produced significant increases in BAL endpoints. At Day 1, Ag NWs increased total cells, inflammatory polymorphonuclear cells (PMNs), and total protein. PMNs persisted for both Ag NW types at Day 7, though not significantly so, and by Day 21, PMNs appeared in line with sham control values. Striking histopathological features associated with Ag NWs included 1) a strong influx of eosinophils at Days 1 and 7; and 2) formation of Langhans and foreign body giant cells at Days 7 and 21. Epithelial sloughing in the terminal bronchioles (TB) and cellular exudate in alveolar regions were also common. By Day 21, Ag NWs were primarily enclosed in granulomas or surrounded by numerous macrophages in the TB-alveolar duct junction. These findings suggest short and long Ag NWs produce pulmonary toxicity; thus, further research into exposure-related health effects and possible exposure scenarios are necessary to ensure human safety as Ag NW demand increases

    Captura gesticular orientada a la docencia a través de tecnología Kinect

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    1. Planteamiento inicial del Proyecto Aplicación orientada a la docencia en donde el objetivo es de captura, reconocimiento y ejecución de la acción requerida por el usuario – docente. Tenemos la utilización de gestos y no de botones lo cual facilitaría y haría una docencia mucho más dinámica de lo que hoy en día tenemos. Pensado para que exista la posibilidad mediante la gesticulación de paso de transparencias de presentaciones docentes. Kinect permite a los usuarios controlar e interactuar con el dispositivo sin necesidad de tener contacto físico con un controlador mediante una interfaz natural de usuario que reconoce gestos, comandos de voz y objetos e imágenes. 2. Objetivos del Proyecto Reconocimiento de las distintas gesticulaciones realizadas por el docente en sus clases tales como movimientos de pantallas, paso de diapositivas, etc.Escuela Técnica Superior de Ingeniería de TelecomunicaciónUniversidad Politécnica de Cartagen

    Application of the zero-range potential model to positron annihilation on molecules

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    In this paper we use a zero-range potential (ZRP) method to model positron interaction with molecules. This allows us to investigate the effect of molecular vibrations on positron-molecule annihilation using the van der Waals dimer Kr2 as an example. We also use the ZRP to explore positron binding to polyatomics and examine the dependence of the binding energy on the size of the molecule for alkanes. We find that a second bound state appears for a molecule with ten carbons, similar to recent experimental evidence for such a state emerging in alkanes with twelve carbons.Comment: 14 pages, 6 figures, to be published in Nuclear Instruments and Methods
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