F-8C digital CCV flight control laws

A set of digital flight control laws were designed for the NASA F-8C digital fly-by-wire aircraft. The control laws emphasize Control Configured Vehicle (CCV) benefits. Specific pitch axis objectives were improved handling qualities, angle-of-attack limiting, gust alleviation, drag reduction in steady and maneuvering flight, and a capability to fly with reduced static stability. The lateral-directional design objectives were improved Dutch roll damping and turn coordination over a wide range in angle-of-attack. An overall program objective was to explore the use of modern control design methodilogy to achieve these specific CCV benefits. Tests for verifying system integrity, an experimental design for handling qualities evaluation, and recommended flight test investigations were specified

Young people today: news media, policy and youth justice

The new sociology of childhood sees children as competent social agents with important contributions to make. And yet the phase of childhood is fraught with tensions and contradictions. Public policies are required, not only to protect children, but also to control them and regulate their behaviour. For children and young people in the UK, youth justice has become increasingly punitive. At the same time, social policies have focused more on children's inclusion and participation. In this interplay of conflict and contradictions, the role the media play is critical in contributing to the moral panic about childhood and youth. In this article, we consider media representations of “antisocial” children and young people and how this belies a moral response to the nature of contemporary childhood. We conclude by considering how a rights-based approach might help redress the moralised politics of childhood representations in the media

Three-Dimensional Kinematics of Hummingbird Flight

Hummingbirds are specialized for hovering flight, and substantial research has explored this behavior. Forward flight is also important to hummingbirds, but the manner in which they perform forward flight is not well documented. Previous research suggests that hummingbirds increase flight velocity by simultaneously tilting their body angle and stroke-plane angle of the wings, without varying wingbeat frequency and upstroke: downstroke span ratio. We hypothesized that other wing kinematics besides stroke-plane angle would vary in hummingbirds. To test this, we used synchronized highspeed (500·Hz) video cameras and measured the threedimensional wing and body kinematics of rufous hummingbirds (Selasphorus rufus, 3·g, N=5) as they flew at velocities of 0–12·m·s–1 in a wind tunnel. Consistent with earlier research, the angles of the body and the stroke plane changed with velocity, and the effect of velocity on wingbeat frequency was not significant. However, hummingbirds significantly altered other wing kinematics including chord angle, angle of attack, anatomical strokeplane angle relative to their body, percent of wingbeat in downstroke, wingbeat amplitude, angular velocity of the wing, wingspan at mid-downstroke, and span ratio of the wingtips and wrists. This variation in bird-centered kinematics led to significant effects of flight velocity on the angle of attack of the wing and the area and angles of the global stroke planes during downstroke and upstroke. We provide new evidence that the paths of the wingtips and wrists change gradually but consistently with velocity, as in other bird species that possess pointed wings. Although hummingbirds flex their wings slightly at the wrist during upstroke, their average wingtip–span ratio of 93% revealed that they have kinematically ‘rigid’ wings compared with other avian species

High-temperature Oxidation of an Alumina-Coated Ni-Base Alloy

Alumina coatings were applied to Ni-20Cr (wt%) using combustion chemical vapor deposition (combustion CVD). Combustion CVD is an open air deposition technique performed in a flame. The oxidation kinetics of coated and uncoated specimens were measured by isothermal oxidation tests carried out in pure flowing air at temperatures of 800, 900, 1,000 and 1,100 C. The alumina coatings reduced the oxidation kinetics at all temperatures. The morphologies and compositions of the alumina coatings were characterized by transmission and scanning electron microscopy, energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy

A new interpretation of total column BrO during Arctic spring

Emission of bromine from sea-salt aerosol, frost flowers, ice leads, and snow results in the nearly complete removal of surface ozone during Arctic spring. Regions of enhanced total column BrO observed by satellites have traditionally been associated with these emissions. However, airborne measurements of BrO and O3 within the convective boundary layer (CBL) during the ARCTAS and ARCPAC field campaigns at times bear little relation to enhanced column BrO. We show that the locations of numerous satellite BrO “hotspots” during Arctic spring are consistent with observations of total column ozone and tropopause height, suggesting a stratospheric origin to these regions of elevated BrO. Tropospheric enhancements of BrO large enough to affect the column abundance are also observed, with important contributions originating from above the CBL. Closure of the budget for total column BrO, albeit with significant uncertainty, is achieved by summing observed tropospheric partial columns with calculated stratospheric partial columns provided that natural, short-lived biogenic bromocarbons supply between 5 and 10 ppt of bromine to the Arctic lowermost stratosphere. Proper understanding of bromine and its effects on atmospheric composition requires accurate treatment of geographic variations in column BrO originating from both the stratosphere and troposphere

Discovery of a New Pulsar Wind Nebula in the Large Magellanic Cloud

We present new high-resolution radio and X-ray observations of the supernova remnant (SNR) B0453-685 in the Large Magellanic Cloud, carried out with the Australia Telescope Compact Array and the Chandra X-ray Observatory respectively. Embedded in the SNR shell is a compact central nebula producing both flat-spectrum polarized radio emission and non-thermal X-rays; we identify this source as a pulsar wind nebula (PWN) powered by an unseen central neutron star. We present a new approach by which the properties of a SNR and PWN can be used to infer upper limits on the initial spin period and surface magnetic field of the unseen pulsar, and conclude that this star was an initial rapid rotator with current properties similar to those of the Vela pulsar. As is the case for other similarly-aged sources, there is currently an interaction taking place between the PWN and the SNR's reverse shock.Comment: 4 pages of text plus 2 embedded EPS figures. Minor changes following referee's report. ApJ Letters, in pres