Drag coefficients for spheres for free molecular flow in nitrogen at satellites' velocities

Momentum transfer by nitrogen molecular beam to surfaces measured as function of angle of incidenc

Development of a superconductor magnetic suspension and balance prototype facility for studying the feasibility of applying this technique to large scale aerodynamic testing

The basic research and development work towards proving the feasibility of operating an all-superconductor magnetic suspension and balance device for aerodynamic testing is presented. The feasibility of applying a quasi-six-degree-of freedom free support technique to dynamic stability research was studied along with the design concepts and parameters for applying magnetic suspension techniques to large-scale aerodynamic facilities. A prototype aerodynamic test facility was implemented. Relevant aspects of the development of the prototype facility are described in three sections: (1) design characteristics; (2) operational characteristics; and (3) scaling to larger facilities

Legacies of British Imperialism in the Contemporary UK Asylum–Welfare Nexus

This article traces the imperial roots of the contemporary asylum–welfare nexus. It explores how English colonial governance exported Poor Law legislation firstly to colonial America (USA) and secondly to British North America (Canada). It argues that these three countries are an Anglophone shared moral space of law and governance, revealing the common unresolved contradictions underpinning contemporary debates about who ‘deserves’ entry, under what conditions, and why. Historical perspectives unsettle assumptions about the primacy of national geopolitical borders and the exceptionalism of contemporary migration. This article uses historical sociology to trace why and how national sovereignty took primacy over municipalities in controlling the mobility of people and the concomitant moral underpinnings. It then draws on new empirical research in three pioneering ‘sanctuary cities’ to explore how cities contest the entwining of welfare and migration governance. However, the article explores how these initiatives often reproduce justifications based on ‘deservingness’ and ‘contribution’. Through tracing the common threads that led to these forms of governance, we can understand they are not self-evident. A historical perspective allows us to ask different questions and open realms of alternative possibilities

Dynamics of a flexible rotor in magnetic bearings

Discussed is a magnetic bearing which was designed and tested in a flexible rotor both as support bearings and as a vibration controller. The design of the bearing is described and the effect of control circuit bandwidth determined. Both stiffness and damping coefficients were measured and calculated for the bearing with good agreement. The bearings were then placed in a single mass rotor as support bearings and the machine run through two critical speeds. Measurements were made of the vibration response in plain bushings and magnetic bearings. Comparisons were also made of the theoretical calculations with the measured peak unbalance response speeds. Finally, runs were made with the magnetic bearing used as a vibration controller

An experimental investigation of an axisymmetric jet in a coflowing airstream

The flow development of an axisymmetric jet exhausting into a moving airstream has been studied. The jet has a Reynolds number of 22,600, and the ratio of the jet velocity to the wind tunnel velocity is 5.1 to 1. The flow field of the axisymmetric jet was examined at locations varying from approximately zero to eight diameters downstream of the orifice. Of primary concern at each downstream location was the mapping of the one point statistical properties of the flow, including mean velocity, turbulent intensity, and intermittency. Autocorrelations and power spectral density curves were determined for both the fluctuating velocity field and the concentration signal at various distances from the jet's center line for different downstream locations. A laser Doppler velocimeter, using a phase locked loop processor, was used to make the desired velocity field measurements which were compared with hot wire anemometer and pressure probe data

Design study of magnetic eddy-current vibration suppression dampers for application to cryogenic turbomachinery

Cryogenic turbomachinery used to pump high pressure fuel (liquid H2) and oxidizer (liquid O2) to the main engines of the Space Shuttle have experienced rotor instabilities. Subsynchronous whirl, an extremely destructive instability, has caused bearing failures and severe rubs in the seals. These failures have resulted in premature engine shutdowns or, in many instances, have limited the power level to which the turbopumps could be operated. The feasibility of using an eddy current type of damping mechanism for the Space Shuttle Main Engine is outlined

The interaction of oxygen atoms with solid surfaces at eV energies Annual status report, 1 Jun. 1968 - 31 May 1969

Interaction of oxygen atoms with solid surfaces at eV energie

RIDGE and InterRidge: Cooperative interdisciplynary studies of mid-ocean ridges

RIDGE (gidge mer-Oisciplinary Boba1 bperiments) is a major research initiative in the United States designed to complement existing research on spreading centers. RIDGE has been designed to integrate exploration, expenment and theory into a major, decade-long effort to understand one of the pnmary processes that have shaped the evolution of our planet. Its objectives are twofold: (1) to provide a focus for a coordinated, interdisciplinary research program directed at geological, hydrothermal and biological processes associated with the formation of oceanic cmst, and (2) to provide a framework within which a rich diversity of investigator-initiated research can be undertaken. The RIDGE initiative has led to parallel efforts in other nations which have recently joined together to form InterRidge, an intemational collaboration of some sixteen countries focused on ridge crest studies

A magnetic damper for first mode vibration reduction in multimass flexible rotors

Many rotating machines such as compressors, turbines and pumps have long thin shafts with resulting vibration problems, and would benefit from additional damping near the center of the shaft. Magnetic dampers have the potential to be employed in these machines because they can operate in the working fluid environment unlike conventional bearings. An experimental test rig is described which was set up with a long thin shaft and several masses to represent a flexible shaft machine. An active magnetic damper was placed in three locations: near the midspan, near one end disk, and close to the bearing. With typical control parameter settings, the midspan location reduced the first mode vibration 82 percent, the disk location reduced it 75 percent and the bearing location attained a 74 percent reduction. Magnetic damper stiffness and damping values used to obtain these reductions were only a few percent of the bearing stiffness and damping values. A theoretical model of both the rotor and the damper was developed and compared to the measured results. The agreement was good

Understanding causes and consequences of going ‘missing’

Key findings • Local authorities and central government define ‘missing’ in different ways reflecting differing concerns and agendas. • There is limited attention given to ‘missing’ unaccompanied young people seeking asylum once they turn 18. • The transition to institutional adulthood (at 18 years) greatly increases young people’s anxieties and fears about their futures. Fear of being apprehended and deported drives many young people with no secure status to disengage from services and abscond. • Disengaging from services means for many an abrupt transition into precarity and destitution. Absconding means relying on community and support networks and may lead to forms of exploitation and vulnerabilit