Abstract. Large Finite Element (FE) models of tires are currently used to predict low frequency behavior and to obtain dynamic model coefficients used in multi-body models for riding and comfort. However, to predict higher frequency behavior, which may explain irregular wear, critical rotating speeds and noise radiation, FE models are not practical. Detailed FE models are not adequate for optimization and uncertainty predictions either, as in such applications the dynamic solution must be computed a number of times. Therefore, there is a need for simpler models that can capture the physics of the tire and be used to compute the dynamic response with a low computational cost. In this paper, the spectral (or continuous) element approach is used to derive such a model. A circular beam spectral element that takes into account the string effect is derived, and a method to simulate the response to a rotating force is implemented in the frequency domain. The behavior of a circular ring under different internal pressures is investigated using modal and frequency/wavenumber representations. Experimental results obtained with a real untreaded truck tire are presented and qualitatively compared with the simple model predictions with good agreement. No attempt is made to obtain equivalent parameters for the simple model from the real tire results. On the other hand, the simple model fails to represent the correct variation of the quotient of the natural frequency by the number of circumferential wavelengths with the mode count. Nevertheless, some important features of the real tire dynamic behavior, such as the generation of standing waves and part of the frequency/wavenumber behavior, can be investigated using the proposed simplified model.

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Acacia gum is an important food emulsifier that presents poor instant properties which can be improved by fluidized bed agglomeration. This study investigated the influence of drying conditions on particle growth kinetics using an in-line particle size monitoring by spatial filter velocimetry. The drying conditions varied according to the binder flow rate and the fluidizing air temperature. The particle growth kinectis showed drying conditions dependence. At mild drying conditions the growth rate and the process yield were higher. The in-line particle size monitoring was useful to observe the influence of the drying conditions on the growth kinetics.Keywords: fluidized bed agglomeration; acacia gum; particle growth kinectis; in-line monitoring.

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This work aimed to investigate the use of inulin as an alternative binder in fluidized bed agglomeration to improve both acacia gum functional and handling properties.Acacia gum was agglomerated in fluidized bed with inulin solution (18.0% wt/wt) at two different fluidizing air temperature (65 and 85 C) and binder feed rate (1.5 ml/min and 3.0 ml/min). The granule growth kinetics and system stability were monitored by a spatial filter velocimetry probe. The influence of process parameters on process yields and product characteristics: final particle size, wettability, and flowability were also evaluated. We observed an increase in particle size and the agglomerated particles showed a short wetting time, indicating that inulin can be successfully used as an alternative binder adding both nutritional and functional value to the acacia gum. Low binder feed rate provided better system stability and larger particle size. Practical ApplicationsThis paper presents inulin as an alternative binder for application in powder food agglomeration processes. The use of inulin has provided improved flowability and wetting properties. Moreover, the inulin may also add functional value to agglomerated foods. Besides, it was possible to monitor particle growth and process stability through a relatively new technique that measures the particle size, spatial filter velocimetry. In this way, it is possible to establish which conditions of temperature and binder feed rate are the most suitable for the agglomeration process.

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