Thunderstorm electrification : precipitation versus convection

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1981.Microfiche copy available in Archives and Science.Vita.Bibliography: p. 235-247.by Earle Rolfe Williams.Ph.D

Small scale simulation of lightning using vertical wires deployed by drones: on the land and sea peak current asymetry

In this work we simulate lightning by means of vertical wires deployed by a multirotor drone under fair weather conditions. These wires, when isolated from ground, acquire an electric potential by virtue of electrostatic induction by the atmospheric potential. When the wires are short circuited to ground or seawater a current is measured sharing some features similar to return strokes in lightning. The results show how currents have higher amplitudes when the wires are short circuited to seawater compared to ground.This work was supported by a research grant from the Spanish Ministry of Economy EXPLORA call with reference ENE2017-91636-EXP and the Grant PID2019-109269RBC42 funded by MCIN/AEI/10.13039/501100011033. This work is also supported by the MIT MISTI Global Seed Funds MIT-Spain ‘La Caixa’ projects “Smart Lightning Protection Systems for Wind Turbines and Aircraft” and “Small Unmanned Airborne Systems for Atmospheric Electricity Research”. Also, the Industrial Doctorate grant of the AGAUR with reference to 2019 DI 039 .Peer ReviewedPostprint (published version

New era of lightning detection from space: application to electric power systems

Information about lightning activity and its parameters is necessary to design and evaluate the lightning protection of an electrical power system. This information can be obtained from ground-based lightning detection networks that provide information on cloud-to-ground lightning strikes with a location accuracy of few hundred meters. Recently, the first satellite-based lightning optical detectors are operating continuously from geostationary orbits. These imagers observe the luminosity escaping from clouds to detect and locate total lightning activity with a spatial accuracy of several kilometers. This allows delineating the initiation and propagation (sometimes over tens to hundreds of kilometers before striking the ground) not observable by the ground-based networks. In this paper, we explore the use of this new technology for lightning protection in power systems.This work was supported by research grants from the Spanish Ministry of Economy and the European Regional Development Fund (FEDER): ESP2017-86263-C4-2-R and PID2019-109269RB-C42. S. Goodman was in part supported by NASA Grant 80NSSC18K1689.Peer ReviewedPostprint (published version

The Emergence of the Pro-Nicene Alliance

This chapter narrates the emergence of the pro-Nicene alliance by arguing that it was a consensus-building movement. It begins by tracing the history of other consensus-building movements in the fractured theological landscape of the years 325-61 in order to demonstrate their development of various consensus-building tactics, which were ultimately used unsuccessfully. The impetus for the pro-Nicene alliance itself was dissatisfaction with, or the failure of, these previous efforts. Pro-Nicenes adopted four tactics of previous consensus-building efforts and deployed them successfully: (1) defining itself as the center between extreme positions, (2) promoting a minimalist creed that nonetheless ruled out extremes to be avoided, (3) acknowledging that the meaning of a creed was not self-evident and producing supplementary material to insure its correct interpretation, and (4) securing imperial patronage. The chapter then turns to shifts in thinking which occurred in the early 360s and made consensus between former opponents possible, taking Athanasius of Alexandria and Basil of Caesarea as paradigmatic examples of these shifts. The chapter concludes by narrating the consolidation and ascendency of the pro-Nicene alliance in the late 370s and early 380s

Hosting the Council in Nicaea: Material needs and Solutions

This chapter examines the physical surroundings and circumstances of the first ecumenical council at Nicaea. The first part summarizes what we know of the city of Nicaea, what it looked like in the early fourth century, and if it had the necessary infrastructure to host a large gathering. The chapter also considers why the council was moved to Nicaea from Ancyra as well as why Nicaea was favored over the nearby imperial capital of Nicomedia. The next part focusses on the location, character, and size of the venue of the council, the palace of Nicaea. After a more general discussion of the complex, the author attempts to shed light on the physical form of the hall in which the bishops gathered by reviewing the evidence for audience halls known from other imperial and private palaces. Both the possibility of the council taking place in a large basilica-like setting and an alternative of the bishops convening inside a rotunda are considered. Finally, there is a brief comparison of the setting of the Nicaean council and contemporary Christian meeting places

The Twenty Canons of the Council of Nicaea

Apart from the very important profession of faith, the Council of Nicaea also promulgated twenty canons, most of which do not receive the same attention in research as the Nicene Creed, although these were already highly esteemed in ancient times. First of all, this chapter provides a brief review of their textual transmission. Besides the original Greek text, which has been handed down in canonical collections and writings of ecclesiastical writers, there are some translations into other ancient languages (Latin, Syriac, Coptic). Then after dividing the twenty canons into various thematic groups (for example, laws pertaining to the clergy, sacraments, ecclesiastical jurisdiction), the second part explains each canon with the aid of previous research literature and interpretations in order to provide a short overview of their purpose and content. The third part deals with the reception of the canons in the early Church by councils, bishops, and ecclesiastical writers, and asks what importance was attributed to the Nicene canons in various canonical sources. Finally, some desiderata for future research are discussed