New developments in blown flap noise technology

The noise technology relating to blown-flap systems is reviewed. There are three general sources of noise: turbomachinery, airframe, and the interaction noise of the jet blowing on the flaps. The latter noise-source area is the most critical and the main subject dicussed. Characteristics of lower surface blown and upper surface blown systems are described, including noise spectra, directivity, jet velocity characteristics, aircraft geometric variation effects, and aircraft forward speed effects. Noise reduction concepts are described, including slowing down the jet flow field by devices and engine cycle modifications, structural geometry and shielding modifications, local flow field modifications of the passive and active type, and the absorption of noise. It is concluded that, while there has been considerable progress in the past several years, low noise characteristics in blown flap aircraft must be largely built in by better application of low noise principles during the design

A land of milk and honey with streets paved with gold: do emigrants have over-optimistic expectations about incomes abroad?

Millions of people emigrate every year in search of better economic and social opportunities. Anecdotal evidence suggests that emigrants may have over-optimistic expectations about the incomes they can earn abroad, resulting in excessive migration pressure, and in disappointment amongst those who do migrate. Yet there is almost no statistical evidence on how accurately these emigrants predict the incomes that they will earn working abroad. In this paper we combine a natural emigration experiment with unique survey data on would-be emigrants’ probabilistic expectations about employment and incomes in the migration destination. Our procedure enables us to obtain moments and quantiles of the subjective distribution of expected earnings in the destination country. We find a significant underestimation of both unconditional and conditional labor earnings at all points in the distribution. This under-estimation appears driven in part by potential migrants placing too much weight on the negative employment experiences of some migrants, and by inaccurate information flows from extended family, who may be trying to moderate remittance demands by understating incomes

Gender differences in health-related quality of life following total laryngectomy

Background: The impact of a total laryngectomy on an individual's life has primarily been measured from a male viewpoint reflecting the demographics of a diagnosis of laryngeal cancer. A small number of studies have looked specifically at females, but very few are comparison studies. Consequently, there is little consistent research regarding any potential gender differences. Aims: To investigate whether there are gender differences in perceptions of health-related quality of life and functional abilities following total laryngectomy. Methods & Procedures: A total of 43 participants (22 males, 21 females), who had undergone a total laryngectomy procedure at least one year previously, took part in the study. They completed The European Organisation for Research and Treatment of Cancer Core Questionnaire Version 3.0 (EORTC QLQ-C30) in conjunction with the disease-specific Head & Neck Cancer Module (QLQ-H&N35). Outcomes & Results: There were no significant differences between males and females on demographic and disease-related variables, except for the following: significantly more females lived alone and changed their employment status following surgery. Males had a significantly higher global health status/quality of life than females (p < 0.05) and significantly higher levels of physical (p = 0.01), emotional (p < 0.01), cognitive (p < 0.05) and social functioning (p < 0.05). After adjusting for differences in living arrangements and change in employment status, differences in emotional and social functioning remained significant. There was a general trend for females to have higher symptom/impairment levels and to report more treatment-related problems, but the majority of these differences were not significant. Conclusions & Implications: Following total laryngectomy, females appear to be worsely affected in aspects of quality of life than males. Emotional and social functioning are particularly vulnerable. The findings imply that rehabilitation programmes after total laryngectomy need to evaluate quality of life and address these specific areas in order to improve patient-reported long-term outcomes

Computational methods for optimal linear-quadratic compensators for infinite dimensional discrete-time systems

An abstract approximation theory and computational methods are developed for the determination of optimal linear-quadratic feedback control, observers and compensators for infinite dimensional discrete-time systems. Particular attention is paid to systems whose open-loop dynamics are described by semigroups of operators on Hilbert spaces. The approach taken is based on the finite dimensional approximation of the infinite dimensional operator Riccati equations which characterize the optimal feedback control and observer gains. Theoretical convergence results are presented and discussed. Numerical results for an example involving a heat equation with boundary control are presented and used to demonstrate the feasibility of the method

Diagnostics of Coronal Magnetic Fields Through the Hanle Effect in UV and IR Lines

The plasma thermodynamics in the solar upper atmosphere, particularly in the corona, are dominated by the magnetic field, which controls the flow and dissipation of energy. The relative lack of knowledge of the coronal vector magnetic field is a major handicap for progress in coronal physics. This makes the development of measurement methods of coronal magnetic fields a high priority in solar physics. The Hanle effect in the UV and IR spectral lines is a largely unexplored diagnostic. We use magnetohydrodynamic (MHD) simulations to study the magnitude of the signal to be expected for typical coronal magnetic fields for selected spectral lines in the UV and IR wavelength ranges, namely the H I Ly-$\alpha$ and the He I 10830 {\AA} lines. We show that the selected lines are useful for reliable diagnosis of coronal magnetic fields. The results show that the combination of polarization measurements of spectral lines with different sensitivities to the Hanle effect may be most appropriate for deducing coronal magnetic properties from future observations.Comment: 15 pages, 5 figures, Frontiers in Astronomy and Space Sciences, 201

Peer-to-peer:is deviant behavior the norm on P2P file-sharing networks?

P2P file-sharing networks such as Kazaa, eDonkey, and Limewire boast millions of users. Because of scalability concerns and legal issues, such networks are moving away from the semicentralized approach that Napster typifies toward more scalable and anonymous decentralized P2P architectures. Because they lack any central authority, these networks provide a new, interesting context for the expression of human social behavior. However, the activities of P2P community members are sometimes at odds with what real-world authorities consider acceptable. One example is the use of P2P networks to distribute illegal pornography. To gauge the form and extent of P2P-based sharing of illegal pornography, we analyzed pornography-related resource-discovery traffic in the Gnutella P2P network. We found that a small yet significant proportion of Gnutella activity relates to illegal pornography: for example, 1.6 percent of searches and 2.4 percent of responses are for this type of material. But does this imply that such activity is widespread in the file-sharing population? On the contrary, our results show that a small yet particularly active subcommunity of users searches for and distributes illegal pornography, but it isn't a behavioral norm

Microbial Load Monitor

The Microbial Load Monitor (MLM) is an automated and computerized system for detection and identification of microorganisms. Additionally, the system is designed to enumerate and provide antimicrobic susceptibility profiles for medically significant bacteria. The system is designed to accomplish these tasks in a time of 13 hours or less versus the traditional time of 24 hours for negatives and 72 hours or more for positives usually required for standard microbiological analysis. The MLM concept differs from other methods of microbial detection in that the system is designed to accept raw untreated clinical samples and to selectively identify each group or species that may be present in a polymicrobic sample

Modeling and control of flexible structures

This monograph presents integrated modeling and controller design methods for flexible structures. The controllers, or compensators, developed are optimal in the linear-quadratic-Gaussian sense. The performance objectives, sensor and actuator locations and external disturbances influence both the construction of the model and the design of the finite dimensional compensator. The modeling and controller design procedures are carried out in parallel to ensure compatibility of these two aspects of the design problem. Model reduction techniques are introduced to keep both the model order and the controller order as small as possible. A linear distributed, or infinite dimensional, model is the theoretical basis for most of the text, but finite dimensional models arising from both lumped-mass and finite element approximations also play an important role. A central purpose of the approach here is to approximate an optimal infinite dimensional controller with an implementable finite dimensional compensator. Both convergence theory and numerical approximation methods are given. Simple examples are used to illustrate the theory