Interpretation of a discovery Vuckovic, Vladan
Serbian journal of electrical engineering,
2006, Letnik:
3, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The paper presents the development of the theory of asynchronous motors since Tesla?s discovery until the present day. The theory of steady state, as we know it today, was completed already during ...the first dozen of years. That was followed by a period of stagnation during a number of decades, when the theory of asynchronous motors was developed only in the framework of the general theory of electric machines, which was stimulated by the problems of the development of synchronous generators and big electric networks. It is only in our time that this simple motor, which was used for a long time just to perform crude tasks, became again the inspiration for the researchers and engineers who enabled it, with the help of power electronics and semi-conductor technology, to be used in the finest drives.
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Some milestones of the systematic history of the Noctuoidea are reviewed, and a full list of the family-group names is given including the respective bibliographical references. Every name has been ...checked for availability according to the ICZN. The following subjective synonyms are indicated: Eublemmini Forbes, 1954 (=*Anthophilidae Duponchel, 1845, unavailable,=*Micradi Stephens, 1850, unavailable, no need for replacement names). According to Art. 40. 2 ICZN, we propose to maintain the names Thaumetopoeinae Aurivillius, 1889 (= Cnethocampides Wallengren, 1861), Psaphidini Grote, 1896 (= Dicopinae Grote, 1882), and Euxoinae Warren, 1909 (= Brotinae Grote, 1882,= Euxoina Beck, 1999 syn. n.), as they are in current use.
In this fourth volume of the landmark Poems for the Millennium series, Pierre Joris and Habib Tengour present a comprehensive anthology of the written and oral literatures of the Maghreb, the region ...of North Africa that spans the modern nation states of Libya, Tunisia, Algeria, Morocco, and Mauritania, and including a section on the influential Arabo-Berber and Jewish literary culture of Al-Andalus, which flourished in Spain between the ninth and fifteenth centuries. Beginning with the earliest pictograms and rock drawings and ending with the work of the current generation of post-independence and diasporic writers, this volume takes in a range of cultures and voices, including Berber, Phoenician, Jewish, Roman, Vandal, Arab, Ottoman, and French. Though concentrating on oral and written poetry and narratives, the book also draws on historical and geographical treatises, philosophical and esoteric traditions, song lyrics, and current prose experiments. These selections are arranged in five chronological "diwans" or chapters, which are interrupted by a series of "books" that supply extra detail, giving context or covering specific cultural areas in concentrated fashion. The selections are contextualized by a general introduction that situates the importance of this little-known culture area and individual commentaries for nearly each author.
This article approaches the problematic of relationships between the World Council of Churches (WCC) and Pentecostalism, mainly from the perspective of membership of Pentecostal churches in the WCC. ...It contents a brief presentation of some prejudices regarding Pentecostals in the ecumenical movement and a historical survey of the relationships between the WCC and Pentecostals, as well as a more detailed analysis of the actual status of this relationship from the perspective of membership of Pentecostal churches in the WCC. The last section assesses possible future scenarios in this regard. It is underlined that the Pentecostal movement is already represented in the WCC by a few small Pentecostal churches and that all the debate on whether to accept new Pentecostal member churches in this ecumenical organization should have as its starting point the reality that Pentecostalism is already part of the WCC. After presenting in detail the last debate in the Permanent Committee on Consensus and Collaboration (PCCC) on the issue of the WCC opening the doors to Pentecostal churches, this article concludes that the WCC should follow its previous policy of analyzing individually each application for membership according to its criteria for accepting new members. While most Pentecostal churches would agree with the basis of the WCC and some might increase their ecumenical engagement at all levels, in the near future at least, Pentecostal churches may still have a long way to go to integrate themselves in a genuine ethos and desire for unity.
Pratt & Whitney's RL10 engine line has a long and rich history, beginning in 1958 and continuing today. This paper provides a historical summary of launch vehicles using RL10 engine derivatives ...dating from 1962 - 2005. The historical launch data is used to derive baseline launch success rates and growth curves for vehicles configured with RL10 engines in the upper stage.Because it was the first liquid hydrogen fueled rocket engine, the RL10 engine launch history provides a unique opportunity to investigate the maturity trends for revolutionary new complex systems. All of the data used in this survey was acquired through publicly-available sources. In all, 190 vehicles configured with RL10 upper stage engines were launched between 1962 and 2005. There were 12 upper stage failures that either failed to reach orbit, or reached a lower, unintended orbit. The early failures were dominated by knowledge gaps in system interactions and operational flight conditions. There is a clear trend of early development growth with an eventual plateau as system knowledge improved as a result of flight experience and more thorough test programs. Failures due to process-based issues (fabrication techniques, quality control, etc.), however, do not appear to exhibit maturity growth. Eventually, as the knowledge-based failures are removed, these process-based failures become the dominant risk driver. Vehicles that use mature, highly-reliable components are still vulnerable to process or functional changes, and failures of this type occur fairly uniformly with flight experience. In order to improve future reliability estimates for such systems, it is important to understand the trends and relationship between the knowledge-based and process-based issues, and determine which class of issues currently dominates. It should be noted that of the 12 upper stage failures, only one was caused by a defective part.
The subject of probability was, of course, motivated initially by its applications. However, there have been earnest attempts to convert it into a branch of pure mathematics, a development suggested ...by the axiomatic basis of the theory and reinforced by a preoccupation with possible measure-theoretic pathologies. This personal retrospective is largely restricted to the post war surge of development. The war itself gave impetus to stochastic modeling of an operation research character, such as E. A. Milne's study of the optimal distribution of fragmentation of anti-aircraft shells. By its nature, the survey is concerned with models and not with inference.
As early as the beginning of the 1970s, there was a strong interest in modifying the corrosion properties of metals by ion implantation. Scientists were excited by the possibility of producing and ...studying metastable or stable surface alloys. However, the initial enthusiasm decreased considerably when the problems arising from the modification of very shallow layers by ion bombardment were realized. The different phases of research and development in this field (1973–1984,1985–1991 and 1991–1995) are reviewed with respect to the major achievements and results obtained. Some important directions of research are illustrated by examples taken from the work of different groups. The present situation is dominated by new techniques such as IBAD, IBEST, PII and high current metal ion implantation. The prospects for further development, in terms of cost reduction and application to corrosion protection, are discussed.
After some introductory remarks about vertical versus horizontal inductive interactions and about planar versus homoiogenetic induction, the author discusses: a) the historical development of the ...more recently studied endo-mesoderm induction in the Urodeles and in the anuran Xenopus laevis, b) the possible causal relationship between endo-mesoderm induction and the initiation of the gastrulation process, and c) the older history of the regional neural induction as initially studied in the Urodeles and only recently analysed in the anuran Xenopus laevis. The essential vertical interaction in the neural induction process both in urodelian and in anuran amphibians is emphasized.
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