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A study of elastic wave motion in a dissipative medium, generated by surface forces is carried out in the present thesis. The main characteristic of the medium considered here, is that the dissipation of energy due to dynamic loads is not linearly proportional to the frequency. The purpose of this study is to describe the dynamic analysis of soils in terms of a linear elastic medium with hysteretic damping, which is a particular case of the Kelvin-Voigt damping with frequency dependent viscosity. Hysteretic damping is denoted using the damping ratio η. With the aid of the Fourier transformation and the Hankel transformation the governing wave equations of motion of the material are solved. Various cases are developed for the prediction of the behaviour of waves in an elastic medium with hysteretic damping. These cases can be applied to railways for high-speed trains and vibrations of foundations. In general the solutions to the problems considered in this thesis are given in terms of stress field, the displacements and the dynamic amplification factor of the vertical displacement. The influence of the hysteretic damping as a function of the damping factor on the magnitude of the results is presented.

Owing to the economic importance of seasonal fluctuations in beach width and the frequent implementation of local beach and shoreface nourishments, coastal managers and scientists increasingly demand coastal state information at smaller spatiotemporal scales. Advanced, automated video techniques provide the means to collect such high-resolution monitoring data. Successful use of video imagery for coastal monitoring requires the quantification of relevant morphological parameters from remotely sensed information. This thesis presents two complementary methods to quantify intertidal and subtidal beach bathymetry from time-averaged video observations. Application of the new methods to a nourished beach at Egmond (The Netherlands) has confirmed their utility in support of coastal management, revealing unexpected morphodynamic behaviour that would have been hard to measure with traditional survey techniques. Stefan Aarninkhof conducted his PhD. research at the Department of Civil Engineering and Geosciences of Delft University of Technology, in close collaboration with Delft Hydraulics.

Liquid crystals comprise a class of materials in which characteristic properties of crystals and liquids are combined. The materials show partly ordered fluid phases, between the common solid and the liquid phases. The combination of order and a high mobility is applied in the well-known liquid crystalline displays (LCD's). This thesis describes the synthesis and characterisation of a series of new disc-shaped liquid crystals (mesogens). It is shown that the actual phase behaviour can be manipulated in various ways: (i) by the introduction of various functional groups laterally attached to the mesogen; (ii) by incorporation of the mesogen into a polymer backbone and (iii) by the application of charge transfer interactions. Combination of these techniques afforded understanding in the complex phase behaviour of these materials as well as in the underlying processes causing this behaviour. Various fascinating observations, such as a new nematic phase and transitions between nematic phases, have resulted in new insights in the field of (disc-shaped) liquid crystals.