Graeme Hocking

During sheet steel production, the steel surface is usually coated with metal alloy for corrosion protection. This can be done by passing the steel through a bath of the molten metal coating, and controlling thickness with a pair of air knives on either side of the ascending steel strip. Surface quality problem, have arisen with recent developments in production. The process was considered at the 2009 Mathematics-and-Statistics-in-Industry Study Group in Wollongong (MIS09) and in subsequent investigations. Previous analyses are extended by the addition of shear terms and by exploring the effect of increased air-jet speeds. A first-order partial differential equation governs the system. This may be used to determine the steady-state coating shape and to study the evolution of any defects that may form.

The coating of steel by dipping through a molten alloy and then stripping off excess coating using an air jet is considered. A first-order partial differential equation is derived and solved both to obtain the steady-state coating shape and to determine the evolution of any defects that may form. Analysis of possible mechanisms for defect formation is discussed. A simple heat transfer model is developed to consider the possibility of phase changes over the relevant section of the process.

Modelling the impacts from tsunami events is a complex task. The approach taken by Geoscience Australia is a hybrid one where two models are combined. The first is one which models the earthquake rupture and subsequent propagation in deep water with the second propagating the tsunami through shallow water and focusing on subsequent inundation and impact ashore. The computer model ANUGA is used for the latter part of the approach and was developed collaboratively between the Australian National University and geoscience Australia. A critical requirement for reliable modelling is an accurate representation of the earth’s surface that extends from the open ocean through the inter-tidal zone into the onshore areas. However, this elevation data may come from a number of sources and will have a range of reliability. There are two questions that arise when data is requested. The first deals with the true variability of the topography. E.g. a flat surface needn’t be sampled as finely as a highly convoluted surface. The second relates to sensitivity; how large if the error in the modelled output if the range of errors in the elevation data is known? ANUGA and similar models can take up days of computer time to simulate a particular scenario, and so full comparative tests for a range of input values is not viable. The main aim of this project was to understand the uncertainties on the outputs of the inundation model based on possible uncertainty on the input data.

Backyard Technology are interested in aspects of aircraft design described by Edward H Lanier in a series of six patents obtained from 1930 to 1933. Lanier's overall aim was to provide an exceptionally stable aeroplane that would both fly normally and recover from undesirable attitudes without pilot aid. Backyard Technology were specifically interested in Lanier's idea of creating a vacuum cavity in the wing by replacing a section of the upper skin of the wing with a series of angled slats, believing that this wing design would give superior lift and stability compared to typical wing designs.

The high-pitched squeal from cornering trains has been a problem for more than a century. The noise is particularly bad for the residents of the Adelaide Hills, where there are some of the tightest curves in the Australian railway network. It is not a trivial problem. Maximum noise levels have been measured at well over 100 decibels 7.5 metres from the track. This can be physically painful. In addition, production of the squeal consumes extra fuel, and wears wheels and rails. Since the privatisation of the Australian interstate rail system, the problem of railway squeal has become the preserve of the Australian Rail Track Corporation (ARTC), whose job it is to manage sections of the nation’s rail infrastructure and sell access to it. ARTC commissioned a study from consulting engineers, Vipac, who measured the noise, suggested what the source might be and made a series of recommendations ranging from further testing to physical changes in wheels and rails. ARTC asked the MISG team to identify the cause of wheel squeal via a frequency analysis, develop models of vibration of the wheel-rail system which could be used to validate the source of the noise, and develop strategies to mitigate the noise. After a solid look at the literature on the problem, and much discussion both amongst those at the conference, and with experts outside, the MISG team concluded that a cycle of sticking and slipping as wheels move along the rail would stimulate vibrations at the right frequency, and that these conditions are most likely to occur on sharp corners, and with badly maintained bogies or worn wheels. Among other measures, the team recommended more stringent maintenance of bogies, and modifying the padding under the sleepers so that the rails are more flexible.

For the control of algal blooming in eutrophic reservoir, two vertical curtains, having depths to cover the epilimnion thickness, were installed across the reservoir. These curtains curtailed the nutrient supply from nutrient-rich inflow to the downstream epilimnion of the reservoir. Thus, nutrients in the downstream epilimnion was gradually depleated, and a significant reduction of algal production was observed there.