13,278 research outputs found
Normalised Root Mean Square and Amplitude of Sidebands of Vibration Response as Tools for Gearbox Diagnosis
Quick assessment of the condition of gearboxes used in helicopters is a safety requirement. One of the most widely used helicopter on-board-mounted condition monitoring system these days is the Health and Usage Monitoring System. It has been specifically designed to monitor the condition of all safety-critical components operating in the helicopter through calculation of so-called condition indicators (CIs) - signal processing routines designed to output a single number that represents the condition of the monitored component. Among number of available parameters, there is a couple of CIs that over the years of testing have earned a reputation of being the most reliable measures of the gear tooth condition. At the same time, however, it has been observed that in some cases, those techniques do not properly indicate the deteriorating condition with the propagation of a gear tooth fault with the period of operation. Hence, three more robust methods have been suggested, which are discussed in this article
Digital flight control research
The results of studies which were undertaken to contribute to the design of digital flight control systems, particularly for transport aircraft are presented. In addition to the overall design considerations for a digital flight control system, the following topics are discussed in detail: (1) aircraft attitude reference system design, (2) the digital computer configuration, (3) the design of a typical digital autopilot for transport aircraft, and (4) a hybrid flight simulator
A new non-perturbative approach to Quantum Brownian Motion
Starting from the Caldeira-Leggett (CL) model, we derive the equation
describing the Quantum Brownian motion, which has been originally proposed by
Dekker purely from phenomenological basis containing extra anomalous diffusion
terms. Explicit analytical expressions for the temperature dependence of the
diffusion constants are derived. At high temperatures, additional momentum
diffusion terms are suppressed and classical Langivin equation can be recovered
and at the same time positivity of the density matrix(DM) is satisfied. At low
temperatures, the diffusion constants have a finite positive value, however,
below a certain critical temperature, the Master Equation(ME) does not satisfy
the positivity condition as proposed by Dekker.Comment: 5 page
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