The random fibre oscillatory behaviour induced by turbulence in the diffuser of an industrial spunbonding rig is measured experimentally. The turbulent air flow is firstly characterised by constant temperature hot-wire anemometry: averaged flow quantities, such as the mean velocity and the turbulent kinetic energy, as well as time dependent quantities, such as the integral time and the energy spectrum, are measured. The influence of the turbulent flow on the dynamics of a nylon fibre of diameter 200 mm and a spunbonding fibre of diameter 18 mm in the diffuser is then investigated by extracting the transverse displacement from images acquired by a digital camera.

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Macro-economic forecasts are used extensively in industry and government even though the historical accuracy and reliability is disputed. Prediction markets have proven to successfully forecast the outcome of elections, sport events and product sales. In this paper we provide a detailed analysis of forecasts generated from a new prediction market for economic derivatives. The proposed market design is specifically designed to forecast macro-economic variables and differs significantly from previous ones. It solves some of the known problems such as low liquidity and partition-dependence framing effects. By using finance methodology we firstly show that the market is reasonably liquid in order to continuously generate forecasts. Secondly the market forecasts performed well in comparison to the 'Bloomberg'-survey forecasts. Thirdly forecasts generated by the market fulfill the weak-form forecast efficiency implying that forecasts contained all publicly available information.

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The behaviour of a fibre subject to the turbulent air flow in the diffuser in the spunbonding process is studied using a three-dimensional dynamics model in which the fibre is discretised as a chain of beads connected by linear and rotational springs. The turbulent air drag acting on the fibre is modelled as a random force, as a function of the mean air velocity, the turbulence intensity, and the spectrum of turbulence. The effect of the air flow parameters and the fibre diameter on the amplitude and the frequency of the fibre oscillations is analysed to understand how the fibre position at the exit of the diffuser is controlled by the turbulent air flow in spunbonding. This in turn will affect fibre laydown and the associated web formation.