· · · Institutional Repository

In this dissertation the impact of the Internet bubble on the development path of the telecommunication sector is being explored and explained. The insights obtained are used to provide recommendations for the formation of government policy and firm strategy in the aftermath. Periods of euphoria are a recurring feature of economic development and the brevity of our "financial memory" and our tendency to pursue quick gains will stimulate the development of future bubbles. While periods of euphoria are inefficient and even wasteful, when they occur as part of the diffusion of a new technological revolution the over-investments in the related infrastructure will provide the basis for reaping the benefits of the new techno-economic paradigm, including its productivity improvements. The process of Telecom Reform has fundamentally changed the "rules of the game" in the sector and has moved strategy formation to the forefront of corporate activity. The Internet bubble period is characterized by a quickly expanding range of business opportunities and an accelerated shift from circuit-mode to packet-mode and from fixed to mobile communication. In the period of frenzy "consensual vision" was taking over. In this euphoric period the incentives appear to have driven the behaviour of managers. The linkage of telecommunication to the diffusion of the new techno-economic paradigm is extending policy formation from Telecom Reform, to ICT policy and beyond. Many of the changes the paradigm shift has evoked are still very much emergent, and have not led to a full alignment between the technological, economical and social domains. Hence, the potential benefits are not yet realized. Therefore, it is recommended to revisit the current policy formation process against the back drop of the diffusion process of the "CT-driven" technological revolution. The prospect that upon an appropriate adjustment of the institutional environment a period of prosperity, a âgolden ageâ, may develop, should present a compelling "incentive for action" for all actors involved.

This dissertation describes the results of a research that was conducted on the permanent deformation of asphalt mixtures. Central to this research was the separate characterization of the contribution of the aggregate skeleton and the bituminous mortar towards resistance to permanent deformation. The mixtures considered in this research included porous asphalt, stone mastic asphalt and dense asphalt concrete. The test program comprised of modulus testing as well as monotonic tension and compression tests on the asphalt mixtures, monotonic and repeated load triaxial tests on the aggregate skeletons along with dynamic shear and direct tension tests on the bitumen and the bituminous mortar. Prior to testing, the compaction homogeneity of the aggregate skeleton and asphalt mixture specimens was examined by means of X-ray tomography. The repeated load triaxial tests conducted on the aggregate skeleton included constant and cyclic confinement tests. The cyclic confinement tests offered a more realistic means of characterizing the permanent deformation behaviour of the aggregate skeleton in comparison to the constant confinement tests. In addition, the permanent deformation under cyclic confinement was higher than the permanent deformation under constant confinement. The approach developed in this research was based on the Desai plasticity model. In order to demonstrate the practical implications of this plasticity approach, two test pavements with a significant amount of permanent deformation were analysed. The analyses showed that the observed permanent deformation could be explained by the approach developed in this research.

This dissertation describes the research into surfacings of orthotropic steel bridge decks. The motive for this research is the frequently reported problems of this type of structures including cracking and rutting of surfacing materials and fatigue related cracks in the steel plate. An intensive experimental program was carried out on three wearing course materials, namely mastic asphalt, guss asphalt and an open synthetic material. The program also included on a bituminous based membrane material. The results of the experimental program were analysed to characterise the complex mechanical behaviour of the different materials. Within the framework of this research, models that describe the response of the surfacing materials were developed, including a newly developed unified model that describes the time-temperature characteristics of many road materials. Furthermore, constitutive relations for elastic as well as inelastic response of the materials were developed. All the developed models were implemented in the Finite Element System CAPA-3D. For verification of the different models results of laboratory tests and full-scale experiments in the LINTRACK APT facility were used. Furthermore, a scientific approach in which the non-linear response of the materials, the geometry and the load are well presented, was used to give an insight into the interaction between the different components of the structure and the vehicle at different temperatures. Because this scientific approach is too sophisticated and expensive for routine analyses and design of the structure, a practical design concept is proposed. In this concept, the geometry and the load are well presented, but the material behaviour is simplified

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.

Simulated Moving Bed (SMB) chromatography is a unit operation in bio(chemical) process industry that is gaining more and more popularity. Possible reasons for the increasing popularity are the continuous operation, high selectivity and considerable savings in the consumption of solvents and resin. The aim of this project was to apply gradient solvent operation to the SMB technology. This decreases the solvent and resin consumption even more, and reduces the costs even more. In addition, less dilution of the product is achieved. Possible drawbacks of the technology are the complicated construction, laborous set-up, and mathematical modeling to get the initial process parameters. The project was financed by the Norwegian company Alpharma, AS, based in Oslo.

Water injection is an integral constituent of most field development scenarios. This injection may take place for secondary recovery and pressure maintenance such as sea water injection. Alternatively, it may take place as a waste water disposal method as in the case of produced water re-injection. Associated with most injection schemes is injectivity decline; where the rate of injection decreases over time at a given constant injection pressure gradient. The phenomenon of injectivity decline is comprised of multiple phenomena such as internal filtration, external filter cake build-up, fracture propagation, relative phase changes within the matrix rock and the associated permeability decline due to each of the described phenomena. The study presented in this thesis addresses some of the key phenomena associated with injectivity decline. Two sub-categories were studied both experimentally and theoretically: internal filtration and external filter cake build-up.

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.