Flutter of Darrieus wind turbine blades: Correlation of theory and experiment

Flutter analysis of two wind turbines was correlated with experimental data for flutter of Darrieus blades

Flutter of Darrieus wind turbine blades

The testing of Darrieus wind turbines has indicated that under certain conditions, serious vibrations of the blades can occur, involving flatwise bending, torsion, and chordwise bending. A theoretical method of predicting the aeroelastic stability of the coupled bending and torsional motion of such blades with a view to determining the cause of these vibrations, and a means of suppressing them was developed

Decoherence induced CPT violation and entangled neutral mesons

We discuss two classes of semi-microscopic theoretical models of stochastic space-time foam in quantum gravity and the associated effects on entangled states of neutral mesons, signalling an intrinsic breakdown of CPT invariance. One class of models deals with a specific model of foam, initially constructed in the context of non-critical (Liouville) string theory, but viewed here in the more general context of effective quantum-gravity models. The relevant Hamiltonian perturbation, describing the interaction of the meson with the foam medium, consists of off-diagonal stochastic metric fluctuations, connecting distinct mass eigenstates (or the appropriate generalisation thereof in the case of K-mesons), and it is proportional to the relevant momentum transfer (along the direction of motion of the meson pair). There are two kinds of CPT-violating effects in this case, which can be experimentally disentangled: one (termed ``omega-effect'') is associated with the failure of the indistinguishability between the neutral meson and its antiparticle, and affects certain symmetry properties of the initial state of the two-meson system; the second effect is generated by the time evolution of the system in the medium of the space-time foam, and can result in time-dependent contributions of the $omega-effect type in the time profile of the two meson state. Estimates of both effects are given, which show that, at least in certain models, such effects are not far from the sensitivity of experimental facilities available currently or in the near future. The other class of quantum gravity models involves a medium of gravitational fluctuations which behaves like a ``thermal bath''. In this model both of the above-mentioned intrinsic CPT violation effects are not valid.Comment: 16 pages revtex, no figure

Antagonistic Managers, Careless Workers and Extraverted Salespeople: An Examination of Personality in Occupational Choice

This paper is an econometric investigation of the choice of individuals between a number of occupation groupings utilising an extensive array of conditioning variables measuring a variety of aspects of individual heterogeneity. Whilst the model contains the main theory of occupational choice, human capital theory, it also tests dynasty hysteresis through parental status variables. The focus is an examination of the relationship between choice and personality with the inclusion of psychometrically derived personality variables. Occupational choice is modelled using multinomial logit estimation using the Household Income and Labour Dynamics in Australia (HILDA) survey data. Human capital variables are found to exhibit strong credentialism effects. Parental status has a small and limited effect on occupation outcomes indicative of only some small dynasty hysteresis. On the other hand, personality effects are found to be significant, relatively large and persistent across all occupations. Further, the strength of these personality effects are such that they can in many instances rival that of various education credentials. These personality effects include but are not limited to: managers being less agreeable and more antagonistic; labourers being less conscientiousness; and sales people being more extraverted.occupational choice, personality traits, credentialism, dynasty hysteresis

Occupational Choice: Personality Matters

In modern societies, people are often classified as "White Collar" or "Blue Collar" workers: that classification not only informs social scientists about the kind of work that they do, but also about their social standing, their social interests, their family ties, and their approach to life in general. This analysis will examine the effect of an individual's psychometrically derived personality traits and status of their parents on the probability of attaining a white collar occupation over the baseline category of a blue collar occupation; controlling for human capital and other factors. The paper uses data from the Household Income and Labour Dynamics in Australia (HILDA) survey to estimate a random effects probit model to capture the effects on the probability of being in a white collar occupation. The results are then examined using the average marginal effects of the different conditioning variables over the whole sample. The analysis confirms the previous findings of human capital theory, but finds that personality and parental status also have significant effects on occupational outcomes. The results suggest that the magnitude of the average marginal effect of parental status is small and the effect of the personality trait "conscientiousness" is large and rivals that of education. Finally, estimates of separate models for males and females indicate that effects differ between the genders for key variables, with personality traits in females having a relatively larger effect on their occupational outcomes due to the diminished effects of education.occupational choice, personality, human capital, dynasty hysteresis

DSN radio science system design and testing for Voyager-Neptune encounter

The Deep Space Network (DSN) Radio Science System presently implemented within the Deep Space Network was designed to meet stringent requirements imposed by the demands of the Voyager-Neptune encounter and future missions. One of the initial parameters related to frequency stability is discussed. The requirement, specification, design, and methodology for measuring this parameter are described. A description of special instrumentation that was developed for the test measurements and initial test data resulting from the system tests performed at Canberra, Australia and Usuda, Japan are given

Wind Tunnel Generation of Sinusoidal Lateral and Longitudinal Gusts by Circulation of Twin Parallel Airfoils

A gust generator capable of producing sinusoidal lateral and longitudinal gusts was developed for the purpose of studying the gust response of a model rotor-propeller in a wind tunnel. The gust generator utilized harmonic circulation control of twin parallel airfoils to achieve the harmonic lift variation required for gust generation. The gust generator design, construction, and testing is described. Typical test results are presented in the form of lateral and longitudinal gust perturbation velocities as a function of generator reduced frequency

Accurate measurement of telemetry performance

Performance of high rate telemetry stations used in the Deep Space Network is verified. Measurement techniques are discussed

Aerodynamic interference effects on tilting proprotor aircraft

The Green's function method was used to study tilting proprotor aircraft aerodynamics with particular application to the problem of the mutual interference of the wing-fuselage-tail-rotor wake configuration. While the formulation is valid for fully unsteady rotor aerodynamics, attention was directed to steady state aerodynamics, which was achieved by replacing the rotor with the actuator disk approximation. The use of an actuator disk analysis introduced a mathematical singularity into the formulation; this problem was studied and resolved. The pressure distribution, lift, and pitching moment were obtained for an XV-15 wing-fuselage-tail rotor configuration at various flight conditions. For the flight configurations explored, the effects of the rotor wake interference on the XV-15 tilt rotor aircraft yielded a reduction in the total lift and an increase in the nose-down pitching moment. This method provides an analytical capability that is simple to apply and can be used to investigate fuselage-tail rotor wake interference as well as to explore other rotor design problem areas