Study of AC losses in medium-sized high temperature superconducting coils

The study of AC losses in superconducting pancake coils is of utmost importance for the development of superconducting devices. Due to different technical difficulties this study is usually performed considering one of two approaches: considering superconducting coils of few turns and studying AC losses in a large frequency range vs. superconducting coils with a large number of turns but measuring AC losses only in low frequencies. In this work, a study of AC losses in 128 turn superconducting coils is performed, considering frequencies ranging from 50 Hz till 1152 Hz and currents ranging from zero till the critical current of the coils. Moreover, the study of AC losses considering two different simultaneous harmonic components is also performed and results are compared to the behaviour presented by the coils when operating in a single frequency regime. Different electrical methods are used to verify the total amount of AC losses in the coil and a simple calorimetric method is presented, in order to measure AC losses in a multi-harmonic context. Different analytical and numerical methods are implemented and/or used, to design the superconducting coils and to compute the total amount of AC losses in the superconducting system and a comparison is performed to verify the advantages and drawbacks of each method.

Sustained competitive advantage of different sized multinational corporations in rural base of the pyramid markets

This thesis explores how multinational corporations of different sizes create barriers to imitation and therefore sustain competitive advantage in rural and informal Base of the Pyramid economies. These markets require close cooperation with local partners in a dynamic environment that lacks imposable property rights and follows a different rationale than developed markets. In order to explore how competitive advantage is sustained by different sized multinational corporations at the Base of the Pyramid, the natural-resource-based view and the dynamic capabilities perspective are integrated. Based on this integration the natural-resource-based view is extended by identifying critical dynamic capabilities that are assumed to be sources of competitive advantage at the Base of the Pyramid. Further, a contrasting case study explores how the identified dynamic capabilities are protected and their competitive advantage is sustained by isolating mechanisms that create barriers to imitation for a small to medium sized and a large multinational corporation. The case study results give grounds to assume that most resource-based isolating mechanisms create barriers to imitation that are fairly high for large and established multinational corporations that operate at the rural Base of the Pyramid and have a high product and business model complexity. On the contrary, barriers to imitation were found to be lower for young and small to medium sized multinational corporations with low product and business model complexity that according to some authors represent the majority of rural Base of the Pyramid companies. Particularly for small to medium sized multinational corporations the case study finds a relationship- and transaction-based unwillingness of local partners to act opportunistically rather than a resource-based inability to imitate. By offering an explanation of sustained competitive advantage for small to medium sized multinational corporations at the rural Base of the Pyramid this thesis closes an important research gap and recommends to include institutional and transaction-based research perspectives.