Aerodynamic characteristics of airplanes at high angles of attack

An introduction to, and a broad overiew of, the aerodynamic characteristics of airplanes at high angles of attack are provided. Items include: (1) some important fundamental phenomena which determine the aerodynamic characteristics of airplanes at high angles of attack; (2) static and dynamic aerodynamic characteristics near the stall; (3) aerodynamics of the spin; (4) test techniques used in stall/spin studies; (5) applications of aerodynamic data to problems in flight dynamics in the stall/spin area; and (6) the outlook for future research in the area. Although stalling and spinning are flight dynamic problems of importance to all aircraft, including general aviation aircraft, commercial transports, and military airplanes, emphasis is placed on military configurations and the principle aerodynamic factors which influence the stability and control of such vehicles at high angles of attack

Property Rights in a Fishery: Regulatory Change and Firm Performance

A new method is introduced and applied to analyse changes in productivity of firms harvesting a natural capital stock. The index-number technique decomposes the contributions of output prices, variable input prices, fixed inputs and productivity to firm profits, adjusted for changes in the natural capital stock. An application of the method is given using micro-level data from a common-pool resource. The indexes provide a ready-made comparison of all firms to the most profitable firm per unit of resource stock. Benchmarking with the decompositions also allows firms and regulators to determine what components are contributing most to economic profits and improve overall industry performance.productivity,profits,natural capital,index numbers

Wind-tunnel free-flight investigation of a model of a spin-resistant fighter configuration

An investigation was conducted to provide some insight into the features affecting the high-angle-of-attack characteristics of a high-performance twin-engine fighter airplane which in operation has exhibited excellent stall characteristics with a general resistance to spinning. Various techniques employed in the study included wind-tunnel free-flight tests, flow-visualization tests, static force tests, and dynamic (forced-oscillation) tests. In addition to tests conducted on the basic configuration tests were made with the wing planform and the fuselage nose modified. The results of the study showed that the model exhibited good dynamic stability characteristics at angles of attack well beyond that for wing stall. The directional stability of the model was provided by the vertical tail at low and moderate angles of attack and by the fuselage forebody at high angles of attack. The wing planform was found to have little effect on the stability characteristics at high angles of attack. The tests also showed that although the fuselage forebody produced beneficial contributions to static directional stability at high angles of attack, it also produced unstable values of damping in yaw. Nose strakes located in a position which eliminated the beneficial nose contributions produced a severe directional divergence

Capacity Reduction and Productivity: The Case of Fishery

The paper presents the first ex-post analysis of profit and productivity of individual vessels following a vessel or licence buyback in a fishery. Using individual firm-level data for the period 1997-2000, the paper analyzes a "natural experiment" of the effects of a 1997 scheme to reduce fishing capacity in the South East trawl fishery of Australia. The scheme was unique in the sense that the buyback was implemented in a fishery managed by individual vessel tradeable harvesting rights rather than input controls. Using an innovative index method that decomposes the contributions of output prices, input prices, vessel size and productivity to relative profits, the economic performance of vessels is analyzed in the year of the buyback and for three years afterwards. Profits for all vessel classes rose over the period 1997-2000 following the 1997 buyback of 27 fishing licenses, but some of the gains were due to a rise in output prices that were independent of the adjustment program. All vessel classes (small and large) also experienced substantial productivity gains immediately following the 1997 license buyback with an average increase over all vessels of 39%. This increase, coincident with a decline in catch per unit of effort for key species, provides strong support that the buyback was successful at improving economic performance. Ongoing productivity improvements for small vessels over the period 1998-2000 following the buyback is attributed to the existence of individual tradeable harvesting rights in the fishery.productivity, capacity reduction, fishery

Understanding stakeholder expectations in higher education

Higher education invests heavily in information technology and information systems, with variable outcomes. Organisations in other sectors, such as engineering, the defence industry, public administration and business, have developed and adopted good practice for the choice, development and operation of software-based systems that are only sometimes understood in higher education. In order to assess the extent to which good practice might assist higher education, the four tertiary institutions in the Western Cape of South Africa were approached and a representative range of academic, administrative, technical and managerial respondents agreed to contribute to the study. Interviews were organised in two parts: the first an open conversation about their involvement with systems, and the second a structured examination of systems-related events that they considered significant. By inspection of those events, bipolar scales were developed by which respondents were able to characterise events (for example as ‘challenging’ or ‘easy’, or as ‘functional’ or ‘dysfunctional’). Respondents rated events on those scales. Repertory Grid analysis was applied so as to investigate which scales correlated with event success. 30 scales (out of 170) proved to be adequately correlated with success, and by principal component analysis they were combined to form ten ‘success scale’ groups, indicating ten areas where the deployment of good practice might be expected to lead to more effective use of improved information systems. A new Reference Model is developed that has a role to play in resolving the transitions between the domains of the Information Management Body of Knowledge (IMBOK)

Understanding IT management in Higher Education

This is a full research paper prepared for submission to an international conference. It is not yet published elsewhere.A meeting of academics concluded that the management of IT resources in education is sub-optimal and under-researched. The extent of IT-related changes indicates a need for strategic management, proper attention to the expectations of stakeholders, and careful management of the implementation of new systems. Representative role players provided both open and structured input to a study that contrasted open coding of transcribed text and structured analysis of repertory grid data. The results of the open coding were limited but the repertory grid data provided useful insight into the management of information technology and information systems in higher education. The principal findings were that the management of the scope of information systems, services and projects must be managed well, and when coupled with risk management this provides the best possibility of successful working. The controlled management of cost, value, and innovation, are revealed to be distinct areas of strategic importance

A Comparative Assessment of Water Markets: Insights from the Murray-Darling Basin of Australia and the Western US

Water markets in Australia’s Murray-Darling Basin (MDB) and the US west are compared in terms of their ability to allocate scarce water resources. The study finds that the gains from trade in the MDB are worth hundreds of millions of dollars per year. Total market turnover in water rights exceeds $2 billion per year while the volume of trade exceeds over 20$4.3 billion (2008 $) spent or committed by urban buyers between 1987 and 2008. The two-market comparison suggests that policy attention should be directed towards ways to promote water trade while simultaneously mitigating the legitimate thirdparty concerns about how and where water is used, especially conflicts between consumptive and in situ uses of water. The study finds that institutional innovation is feasible in both countries and that further understanding about the size, duration, and distribution of third-party effects from water trade, and how these effects might be regulated, can improve water markets to better manage water scarcity.water markets, US west, Murray-Darling Basin, gains from trade