Search results for "Aerospace"
showing 10 items of 450 documents
Effect of caffeine on simulator flight performance in sleep-deprived military pilot students.
2007
Caffeine has been suggested to act as a countermeasure against fatigue in military operations. In this randomized, double-blind, placebo-controlled study, the effect of caffeine on simulator flight performance was examined in 13 military pilots during 37 hours of sleep deprivation. Each subject performed a flight mission in simulator four times. The subjects received either a placebo (six subjects) or 200 mg of caffeine (seven subjects) 1 hour before the simulated flights. A moderate 200 mg intake of caffeine was associated with higher axillary temperatures, but it did not affect subjectively assessed sleepiness. Flight performance was similar in both groups during the four rounds flown und…
Clinical verification of a unilateral otolith test.
1992
Abstract In a previous study13 we reported promising results for a new test to differentiate in vivo unilateral otolith functions. That study pointed to a need for further validation on known pathological cases. In this presentation we will detail the results gathered on a group of clinically verified vestibular defectives (verum) and a normal (control) group. The subjects in the verum group were former patients of the ENT clinic of the university hospital. These subjects had usually suffered from neurinoma of the VIIth cranial nerve or inner ear infections. All had required surgical intervention including removal of the vestibular system. The patients were contacted usually two or more yea…
DIFERENÇAS DE GÊNERO NA DIABETES: UM PONTO DE PARTIDA PARA OTIMIZAR A QUALIDADE DE VIDA
2020
Objetivo: analisar as diferenças de gênero na qualidade de vida e indicadores antropométricos entre pessoas com diabetes tipo 2 (DM2) e sem DM2. Método: Estudo quantitativo de caráter transversal realizado no Centro Hiperdia de Viçosa-Minas Gerais, com 117 indivíduos diagnosticados com DM2 e 81 controles (CTL), com idade igual ou superior a 40 anos. Utilizou-se análise univariada para as variáveis sociodemográficas e teste t de Student para comparação das médias na qualidade de vida e nos indicadores antropométricos. Resultados: na presença da diabetes a qualidade de vida das mulheres piora em maior medida comparada à dos homens, sobre tudo do ponto de vista mental. Mulheres apresentam va…
Prácticas pedagógicas universitarias para el conocimiento mutuo desde las artes y la pedagogía visual
2019
El articulo plantea la exposicion de una serie de experiencias vinculadas a la investigacion educativa en las aulas universitarias que tiene como nexo comun la posibilidad de generar disrupciones educativas, la busqueda del conocimiento del otro, del alumno y del companero de aula, y el conocimiento de uno mismo como base de toda practica docente. Las experiencias expuestas se vinculan a temas como el silencio frente al ruido como via de autoexploracion, la observacion del otro frente al nosotros, la autoexploracion a partir del objeto cotidiano mediante la transfiguracion de significados de la estetica kitsch, el ejercicio del libre pensamiento y la visualizacion de las practicas docentes.…
The OAPA/DPSFA: solar physics, instrumental expertise, and the XACT facility
2001
The potential contribution to Solar Orbiter hardware, calibration and testing from the Palermo group (Osservatorio Astronomico di Palermo G.S. Vaiana + Sezione di Astronomia del Dipartimento di Scienze Fisiche ed Astronomiche (DpSFA), Università di Palermo) will be mostly based on the XACT facility and the related expertise. The X-ray Astronomy Calibration and Testing (XACT) facility of Osservatorio Astronomico di Palermo "G.S. Vaiana" (OAPA) includes vacuum systems, sources, monochromators, detectors, mechanical manipulators, clean room, etc. that permits us to perform measurements in the spectrum ranging from visible light to soft X-rays (0.001 - 10 keV). The facility is currently used in…
On reliability of systems with moving material subjected to fracture and instability
2015
Abstract The reliability of systems with moving cracked elastic and isotropic material is considered. The material is modeled as a moving plate which continually has a crack on the edge. The plate is subjected to homogeneous tension acting in the traveling direction and the tension varies temporally around a constant value, the set tension. The tension and the length of the crack are modeled by an Ornstein–Uhlenbeck process and an exponential Ornstein–Uhlenbeck process, respectively. Failure is regarded as the state at which the plate becomes unstable or fractures (or both) and a lower bound for the reliability of the system is derived. Considering reliability of the system leads to first p…
Stochastic analysis of the critical velocity of an axially moving cracked elastic plate
2014
In this study, a probabilistic analysis of the critical velocity for an axially moving cracked elastic and isotropic plate is presented. Axially moving materials are commonly used in modelling of manufacturing processes, like paper making and plastic forming. In such systems, the most serious threats to runnability are instability and material fracture, and finding the critical value of velocity is essential for efficiency. In this paper, a formula for the critical velocity is derived under constraints for the probabilities of instability and fracture. The significance of randomness in different model parameters is investigated for parameter ranges typical of paper material and paper machin…
TAKEOFF AND LANDING ROBUST CONTROL SYSTEM FOR A TANDEM CANARD UAV
2005
In spite of modern wide improvements in UAV’s technologies, a few number of such a vehicles is fully autonomous from takeoff to landing . So, either autonomous operation or operation with minimal human intervention is, actually, the primary design goal for the UAV’s researchers. The core of the problem is the design of the landing and takeoff control system. The objective of this paper is to design a control system in which the same state variables are controlled during both the descending/ascending path and the flare, tacking into account the actual ground effect. Robust control techniques are employed with the aim to cope with atmospheric turbulence, measurement noise, parameter variation…
Risk Assessment of Fuel Quantity Indicator Replacement in ATR72 Aircraft
2015
Aircraft maintenance activities are rife with opportunities for error. The concurrent in-flight failure of all of the engines of a non-scheduled airline flight and the following list of human lives highlight one of these opportunities. As commonly recognized among flight operators, each flight safety agency follows the criteria of the International Civil Aviation Organization Annex 16 in which all the evidences of the technical investigation pave the way for avoiding future flight accidents or incidents. On the other hand, when the Italian penal procedure code was applied for the Tuninter aircraft ATR 72 (identification code TS-LBB) crash at issue on 6 August 2005 near Palermo (Italy), the…
An Extended Kalman Filter-Based Technique for On-Line Identification of Unmanned Aerial System Parameters
2015
ABSTRACT: The present article deals with the identification, at the same time, of aircraft stability and control parameters taking into account dynamic damping derivatives. Such derivatives, due to the rate of change of the angle of attack, are usually neglected. So the damping characteristics of aircraft dynamics are attributed only on pitch rate derivatives. To cope with the dynamic effects of these derivatives, authors developed devoted procedures to estimate them. In the present paper, a complete model of aerodynamic coefficients has been tuned-up to identify simultaneously the whole set of derivatives. Besides, in spite of the employed reduced order model and/or decoupled dynamics, a s…