14 research outputs found
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Motion of a non-axisymmetric particle in viscous shear flow
We examine the motion in a shear flow at zero Reynolds number of particles with two planes of symmetry. We show that in most cases the rotational motion is qualitatively similar to that of a non-axisymmetric ellipsoid, and characterised by a combination of chaotic and quasiperiodic orbits. We use KolmogorovâArnoldâMoser (KAM) theory and related ideas in dynamical systems to elucidate the underlying mathematical structure of the motion and thence to explain why such a large class of particles all rotate in essentially the same manner. Numerical simulations are presented for curved spheroids of varying centreline curvature, which are found to drift persistently across the streamlines of the flow for certain initial orientations. We explain the origin of this migration as the result of a lack of symmetries of the particleâs orientation orbit.</jats:p
Building Knowledge and Skills to Use Seasonal Climate Forecasts in Property Management Planning
Few in Australian agriculture had heard of the El Niño/Southern Oscillation (ENSO) phenomenon and its impact upon Australian climate or agriculture before 1990. Today, few Australian farmers, agri-business people or scientists are not aware of its impact. This change was partly stimulated by revisions to the National Drought Policy in 1990, which introduced a major change in the role of government services. Emphasis was shifted from providing subsidies to providing information so that farmers could be more self-sufficient in managing the climatic risks they faced. Training initiatives for farmers and land managers were initiated through the National Property Management Planning Program. This paper outlines the property management planning process, details how information on seasonal climate forecasting was made available so that the necessary knowledge and skills to use it effectively in farm management could be developed, and discusses what has been learnt in the process and the major issues for the immediate future.
The Property Management Planning (PMP) process embraces all aspects of property management and is a strategic planning approach to property management. PMP has an emphasis on participative problem solving and includes: reviewing and developing personal goals, natural resource assessment and physical planning, sustainable agricultural production, ecological considerations, business and financial management, marketing, drought preparedness and risk management. The PMP process provides the context for developing seasonal climate knowledge and skills within a strategic planning and farm decision-making framework. Climate and seasonal forecasting information has been made available in a diverse range of forms ranging from print and electronic media to structured workshops. The communication and training processes instigated were very successful at building knowledge and understanding of seasonal climate forecasting. However, this is a necessary but not sufficient condition for its effective application in farm management. Effective application of forecasts involves their use to improve decisions. Feedback from surveys indicates that many primary producers now understand the process of ENSO and believe that seasonal climate outlook information can be used profitably in their business. Many are now considering this information in their decision-making processes. The challenge for the future is to develop training tools/processes that enable analysis of decision options in conjunction with seasonal forecast information and other factors, so that management skill in using forecasts effectively can be enhanced. The lessons we have learnt throughout this process and the insights gained into adult learning are discussed and appear to conform with experiences of others