A wide-speed-range hybrid variable-reluctance/permanent-magnet generator for future embedded aircraft generation systems

This paper presents recent research into the use of an embedded generation system as an alternative to the emergency ram air turbine on aircraft, the proposal being to utilize the windmill effect of the low-pressure turbine of the main aircraft engine for emergency power generation. A novel topology of a high specific output ac permanent-magnet generator is described that has been designed to be driven directly from the low-pressure turbine via an integral fixed-ratio gearbox, the requirement being to generate a regulated 270-V dc 0-20-kW emergency supply over a 12:1 3000-36000-r/min generator shaft speed range. The methodologies behind the machine design and operation are described together with test results taken from a prototype generator system.     

Managing People to Promote Innovation

There is growing evidence available to suggest that Human Resource Management (HRM) practice is an important predictor of organizational performance. Drawing upon organizational learning perspectives, we argue that HRM systems also have the potential to promote organizational innovation. We present longitudinal data from thirty‐five UK manufacturing organizations to suggest that effective HRM systems – incorporating sophisticated approaches to recruitment and selection, induction, appraisal and training – predict organizational innovation in products and production technology. We further show that organizational innovation is enhanced where there is a supportive learning climate, and inhibited (for innovation in production processes) where there is a link between appraisal and remuneration.     

Taxonomy of interpolation constraints on recursive subdivision surfaces

Published online: 14 May 2002     

Videoendoscopic diagnosis of esophageal motility disorders

PURPOSE: Looking for a valid, reliable, and feasible method to collect data on the performances of practicing family physicians, the authors compare the measurement characteristics of a multiple-station examination (MSE) using standardized patients with those of a video assessment of regular consultations in daily practice (practice video assessment, PVA). METHOD: In a cross-sectional study, consultations of 90 family physicians were videotaped both in an MSE and in their daily practices. Peer-observers used a validated instrument (MAAS-Global) to assess the physicians' communication with patients and their medical performances. The physicians were randomly divided into two groups, comparable for demographic characteristics, and half underwent the assessments in reverse order to test for time-order effects. Content validity, criterion validity, reliability, and feasibility of the two methods were compared. RESULTS: Content validity of the PVA was superior to that of the MSE, since the domain of general family practice care was better covered. Observed participants judged the videotaped practice consultations to be "natural," whereas hardly any family physician, after reviewing the videotaped consultations of the MSE, recognized his or her usual working style. Specific criteria made it possible to standardize real practice. Concerning criterion validity, only the medical-performance components of the two methods correlated. No correlation was found for the communication components. Real-practice performance proved to be less influenced by observation than was performance during the MSE. The reliabilities of the two methods, expected to be better in the controlled MSE, were comparable. The administration of the PVA was more flexible, less costly, and better accepted by the family physicians than was that of the MSE. CONCLUSION: Assessment for quality improvement of family physicians' practices by video observation in daily practice is superior to video assessment in a simulated setting using standardized patients.     

The Privatisation of Public Property: the Development of a Shopping Mall in Sydney and its Implications for Governance through Spatial Practices

This article examines the planning application and current operation of a new shopping mall in Sydney. I use this analysis to argue that the owners of the mall, Westfield, govern, through spatial practices, the physical space in the mall and the shopping practices of the people who enter the mall. By the term govern I mean the spatial practices by which Westfield controls the shopping area of the mall. I follow the idea of governance inspired by the governmentality literature to show that those connected with the mall are shaped by spatial practices which envisages subjects which are morally free and yet are shaped by shopping mall practices (Foucault, 1975, 1980).

By these spatial practices, I argue, Westfield creates a certain ambience in the mall, which conveys the message that the mall is an attractive and safe location, which welcomes certain customers and excludes others. This collective impression of mall atmosphere, I argue acts as a spatial practice, which in effect governs the mall.

One of the features of shopping malls is that public or civic space is replaced with 'semi-public space' owned by developers. In this context the protection of private property has coalesced with the preservation of public order (Gray and Gray, 2000, p. 23). In shopping malls people considered disruptive to shopping are excluded and shops found in the high street such as pawnshops and second-hand bookshops are not granted a tenancy. Other unwelcome folk include the homeless and groups of teenagers.

n this article I plan to analyse the spatial practices which restrict full public access to such places as the Hornsby shopping mall. Accordingly, I firstly show that the concept of property should rightly be seen as containing social ideas, secondly I discuss the nature of spatial practices, which materially and discursively lead to the exclusion of certain people and thirdly, describe notions of community which help define who are proper mall entrants.     

Cyclic loading and fatigue in ice

Isotropic polycrystalline ice was subjected to cyclic loading in uniaxial compression at ?5°C, with stress limits 0–2 and 0–3 MPa, and frequencies in the range 0.043 to 0.5 Hz. Stress-strain records showed hysteresis loops progressing along the strain axis at non-uniform rates. The effective secant modulus, which was about half the true Young's modulus, decreased during the course of a test. The elastic strain amplitude and the energy dissipated during a loading cycle both increased with increase of time and plastic strain. Strain-time records gave mean curves which were identical in form to classical constant-stress creep curves, with a small cyclic alternation of recoverable strain about the mean curve. The inflection point of the “creep curve”, marking the transition from strain hardening to strain softening, occurred at a plastic strain of 1% (±0.1%), which is about the same as the “ductile failure strain” found in constant stress creep tests and in constant strain-rate tests on ice of the same type at the same temperature. The dissipation of strain energy up to this “failure point” was much higher for the cyclic tests than for corresponding quasi-static tests ? 100 to 600 kPa (or kN-m/m³) in comparison to about 30 kPa. The number of cycles taken to reach the “failure point” was of no direct significance, varying greatly with stress amplitude and with frequency. The results of the tests suggest that maximum resistance under compressive cyclic loading occurs at an axial plastic strain of about 1%, which is essentially the same as the failure strain for ductile yielding under constant stress and under constant strain-rate.     

Reviews

FARMED LANDSCAPES: THE WAY AHEAD by the Agrolandscapes Working Party. RIBA Bookshops, 1981. £1 (paperback).

ECOLOGY AND PLANNING by P.H.Selman, George Godwin, London, 1981.

THE MAKING OF NEIGHBOURHOOD OPEN SPACES: COMMUNITY DESIGN, DEVELOPMENT AND MANAGEMENT by Mark Francis, Lisa Cashdan & Lynn Paxson. Center for Human Environments, City University of New York, 1981.

WATER PLANNING IN BRITAIN by Dennis J. Parker and Edmund C. Penning-Rowsell. Resources Management Series Volume 1, Editors Richard Munton and Judith Rees. George Allen and Unwin, London, 1980.

COUNTRYSIDE PLANNING YEARBOOK edited by Andrew Gilg. Volume 3, 228 pages. Geo Books, Norwich, 1982.     

Mechanical properties of polycrystalline ice: An assessment of current knowledge and priorities for research: Report prepared for the International Commission on Snow and Ice,with support from the U.S. National Science Foundation

Systematic knowledge of the mechanical properties of ice is a fundamental requirement for the solution of a wide range of problems in the earth sciences and engineering. Past research has been characterized by specialized studies, involving a variety of motivations and scientific disciplines, without much overall coordination. When the results of this research are synthesized, a reasonably coherent picture emerges, but there are major gaps in knowledge. From the deduced behavior of ice, and from informed speculation where data are lacking, a coherent plan for future research can be developed. This report summarizes existing knowledge and proposes experiments and test programs for a new research thrust. The studies that are proposed can be expected to yield significant benefits in glacier studies, ice engineering, and the mechanics of frozen ground.     

Sequential Destruction Method for Monte Carlo Evaluation of System Reliability

Circumstances favoring the use of Monte Carlo methods for evaluating the reliability of large systems are discussed. A new method, that of Sequential Destruction (SD) is introduced. The SD method requires no preparatory topological analysis of the system, and remains viable when element failure probabilities are small. It applies to a variety of reliability measures and does not require element failures to be s-independent. The method can be used to improve the performance of selective sampling techniques. Substantial variance reductions, as well as computational savings, are demonstrated using a sample system with more than 100 elements.