1,038 research outputs found
26. Pagan Monotheism in Late Antiquity, edited by P. Athanassiadi & M. Frede
No full textFoschia Laurence. 26. Pagan Monotheism in Late Antiquity, edited by P. Athanassiadi & M. Frede. In: Revue des Études Grecques, tome 113, Juillet-décembre 2000. pp. 688-689
Fyrskibsliv i gamle dage
No full textFrede Bak har tidligere skrevet i museets årbog om Læsøboernes traditionsrige sejlads på Grønland. Benne gang er emnet Læsøboernes tjeneste fyrskibe og her specielt på det lokale LÆSØ TRINDE
Galeasefører og meget mere i Grønland
No full textFrede Bak, der i særlig grad har beskæftiget sig med Læsø og øens indbyggere og leveret artikler derom til flere årbøger, har også tidligere skrevet artikler til Handels- og Søfartsmuseets årbøger om grønlandske emner. For nogle år siden stiftede han bekendtskab med Christian Nielsens dagbog fra Grønland, hvorfra han brugte enkelte optegnelser i sin historie om sin morfar, der var styrmand i KGH. Nu har forfatteren atter haft fat i dagbogen, og det er der kommet efterfølgende artikel ud af
Michael Frede, A Free Will. Origin of the Notion in Ancient Thought
No full textLe décès de Michael Frede en 2007 avait laissé inédites six leçons données par lui à l’Université de Californie au titre de 84th Sather Professor of Classical Literature (1997-1998). La parution d’une version définitive de ces leçons était prévue dès l’origine dans les Sather Classical Lectures Series, mais avait été sans cesse repoussée par M. Frede, qui manifestement souhaitait constituer un complément de recherche pour livrer au public une thèse originale pleinement étayée. Il s’agissait e..
Overview of Single-Phase Grid-Connected Photovoltaic Systems
No full textA continuous booming installation of solar photovoltaic (PV) systems has been witnessed worldwide. It is mainly driven by the imperative demand of “clean” power generation from renewables. Grid-connected PV systems will thus become an even more active player in the future mixed power systems, which are linked together by a vast of power electronics converters and the power grid. In order to achieve a reliable and efficient power generation from PV systems, more stringent demands have been imposed on the entire PV system. It, in return, advances the development of the power converter technology in PV systems. This chapter thus gives an overview of the advancement of power electronics converters in single-phase grid-connected PV systems, being commonly used in residential applications. Demands to single-phase grid-connected PV systems and the general control strategies are also addressed in this chapter
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The Seventh Letter: A Discussion of Myles Burnyeat and Michael Frede, The Pseudo-Platonic Seventh Letter
No full textBurnyeat and Frede argue that the seventh of the letters ascribed to Plato is no more genuine than any other letter purporting to be from a philosopher before Epicurus; that its true author is far too remote from Plato for it to give any reliable evidence about Plato’s thoughts and activities; and that it is to be appreciated as a fine tragedy in prose. This review criticizes some of the details of their arguments, while endorsing and amplifying their conclusion
Renewable Energy Systems:Technology Overview and Perspectives
No full textIn this chapter, essential statistics demonstrating the increasing role of renewable energy generation are first discussed. A state-of-the-art review section covers the fundamentals of wind turbine and photovoltaic (PV) systems. Schematic diagrams illustrating the main components and system topologies are included. Also, the increasing role of power electronics is explained as an enabler for renewable energy integration and for future power systems and smart grids. Recent examples of research and development, including new devices and system installations for utility power plants and for residential and commercial applications, are provided. Fuel cells, solar thermal, wave generators, and energy storage systems are also briefly presented and illustrated. Challenges and future trends for the technologies in 2025 are summarized in a table for onshore and offshore wind energy; solar power, including PV and concentrating solar power; wave energy; fuel cells; and storage with batteries and hydrogen, respectively. Recommended further readings on topics of electric power engineering for renewable energy are included in the final section
Overview of Maximum Power Point Tracking Techniques for Photovoltaic Energy Production Systems
No full textA substantial growth of the installed photovoltaic (PV) systems capacity has occurred around the world during the last decade, thus enhancing the availability of electric energy in an environmentally friendly way. The maximum power point tracking (MPPT) technique enables to maximize the energy production of PV sources, despite the stochastically varying solar irradiation and ambient temperature conditions. Thereby, the overall efficiency of the PV energy production system is increased. Numerous techniques have been presented during the last decades for implementing the MPPT process in a PV system. This chapter provides an overview of the operating principles of these techniques, which are suited for either uniform or nonuniform solar irradiation conditions. The operational characteristics and implementation requirements of these MPPT methods are alsoanalyzed in order to demonstrate their performance features
Power Electronics and Controls for Large Wind Turbines and Wind Farms
No full textWind power represents a major and growing source of renewable energy for electric power systems. This chapter provides an overview of state-of-the-art technologies and anticipated developments in the area of power electronic drives, controls, and electric generators for large multi-megawatt (MW) wind turbine (WT) systems. The principal components employed in a turbine for energy conversion from wind to electricity are described, and the main solutions that are commercially available are briefly reviewed. The specific issues of complex mission profiles, grid codes, and also reliability are discussed. The topics of power electronics, ranging from devices to circuit topologies, ans similar matters for electric generators, together with the results of optimal design studies are included. It is shown that the individual power rating of WTs has increased over the years and technologies required in order to reach and even exceed a power rating of 10 MW are discussed. The role of power electronics for improving the operation of WTs and ensuring compliance with power grid codes is analyzed with a view to produce fully controllable generation units suitable for a tight integration into the power grid and large-scale deployment in the future smart power systems
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