scholarly journals ‘…a paper …I hold to be great guns’: a commentary on Maxwell (1865) ‘A dynamical theory of the electromagnetic field’

2015 ◽  
Vol 373 (2039) ◽  
pp. 20140473 ◽  
Author(s):  
Malcolm Longair
Keyword(s):  
Electromagnetic Field ◽  
Dynamical Theory ◽  
First Century ◽  
Displacement Current ◽  
Field Equations ◽  
Newtonian Physics ◽  
Mechanical Models ◽  
Theory Of Fields ◽  
Physical Phenomena

Maxwell's great paper of 1865 established his dynamical theory of the electromagnetic field. The origins of the paper lay in his earlier papers of 1856, in which he began the mathematical elaboration of Faraday's researches into electromagnetism, and of 1861–1862, in which the displacement current was introduced. These earlier works were based upon mechanical analogies. In the paper of 1865, the focus shifts to the role of the fields themselves as a description of electromagnetic phenomena. The somewhat artificial mechanical models by which he had arrived at his field equations a few years earlier were stripped away. Maxwell's introduction of the concept of fields to explain physical phenomena provided the essential link between the mechanical world of Newtonian physics and the theory of fields, as elaborated by Einstein and others, which lies at the heart of twentieth and twenty-first century physics. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society .

Maxwell, Measurement, and the Modes of Electromagnetic Theory

2014 ◽  
Vol 45 (2) ◽  
pp. 303-339 ◽  
Author(s):  
Bruce J. Hunt
Keyword(s):  
Electromagnetic Field ◽  
Mechanical Model ◽  
Dynamical Theory ◽  
Electromagnetic Theory ◽  
Field Equations ◽  
James Clerk Maxwell ◽  
Engineering Approach ◽  
Mechanical Explanation ◽  
Technological Context ◽  
Apparent Shift

In 1861–62, James Clerk Maxwell published “On Physical Lines of Force,” in which he laid out a detailed mechanical model of the ether and argued that it could account not only for electromagnetic phenomena but for light as well. In 1864, he followed with “A Dynamical Theory of the Electromagnetic Field,” in which he derived the electromagnetic equations from general dynamical considerations without invoking any mechanical model of the ether. Why the shift? Did Maxwell regard his mechanical model as mere scaffolding, to be cast aside once it had led him to the proper field equations? Or did he remain committed to the goal of a purely mechanical explanation, but find it useful to free his main results, particularly his electromagnetic theory of light, from dependence on the specifics of an admittedly speculative model? To understand the apparent shift Maxwell’s thinking underwent between 1862 and 1864, I propose that we look closely at what he was doing in 1863. He spent that year working hard for the British Association Committee on Electrical Standards, collaborating with telegraph engineers to establish the value of the ohm and laying the groundwork for measuring the ratio of electrostatic to electromagnetic units, a key quantity in his electromagnetic theory of light. This experience led Maxwell to adopt for a time an engineering approach that focused on establishing relationships between measureable quantities rather than devising hypothetical mechanisms. Maxwell’s electromagnetic work thus had closer ties to the technological context of the day than has generally been recognized.

scholarly journals Solitary Waves in Abelian Gauge Theories

2008 ◽  
Vol 8 (2) ◽  
Author(s):  
Vieri Benci ◽  
Donato Fortunato
Keyword(s):  
Electromagnetic Field ◽  
Electromagnetic Fields ◽  
Solitary Waves ◽  
Lower Order ◽  
Gauge Theories ◽  
Order Term ◽  
Lower Order Term ◽  
Field Equations ◽  
Abelian Gauge ◽  
Physical Phenomena

AbstractAbelian gauge theories consist of a class of field equations which provide a model for the interaction between matter and electromagnetic fields. In this paper we analyze the existence of solitary waves for these theories. We assume that the lower order term W is positive and we prove the existence of solitary waves if the coupling between matter and electromagnetic field is small. We point out that the positiveness assumption on W implies that the energy is positive: this fact makes these theories more suitable to model physical phenomena.

A reformulation of the Born-Infeld electrodynamics

1960 ◽  
Vol 257 (1288) ◽  
pp. 32-43 ◽  
Keyword(s):  
Point Charge ◽  
Equations Of Motion ◽  
Hamiltonian Formulation ◽  
Charged Particles ◽  
Dynamical Theory ◽  
Action Principle ◽  
Field Equations ◽  
Maxwell Electrodynamics ◽  
Recent Developments ◽  
Theory Of Fields

The electrodynamics proposed by Born & Infeld in 1934 differs from the Maxwell electrodynamics for very strong fields and gives a finite total energy for the field around a point charge. At that time not much was known about the dynamical theory of fields, and recent developments of this subject enable one to give a better formulation of the Born-Infeld theory. The basis is a comprehensive action principle that determines both the field equations and the equations of motion of charged particles. From this action principle a Hamiltonian formulation is obtained, the various Hamiltonian constraints being worked out. The classical theory is found to be completely satisfactory, but difficulties arise with the passage to the quantum theory, which appear to be insoluble with present methods of quantization.

THE ROLE OF ACCOUNTING IN PUBLIC EXPENDITURE AND MONETARY POLICY IN THE FIRST CENTURY AD ROMAN EMPIRE

1995 ◽  
Vol 22 (2) ◽  
pp. 117-129 ◽  
Author(s):  
David Oldroyd
Keyword(s):  
Monetary Policy ◽  
Roman Empire ◽  
Financial Planning ◽  
Public Expenditure ◽  
First Century ◽  
Financial Control ◽  
The Public ◽  
Monetary System ◽  
Epigraphic Evidence

Previous authors have argued that Roman coinage was used as an instrument of financial control rather than simply as a means for the state to make payments, without assessing the accounting implications. The article reviews the literary and epigraphic evidence of the public expenditure accounts surrounding the Roman monetary system in the first century AD. This area has been neglected by accounting historians. Although the scope of the accounts supports the proposition that they were used for financial control, the impetus for keeping those accounts originally came from the emperor's public expenditure commitments. This suggests that financial control may have been encouraged by the financial planning that arose out of the exigencies of funding public expenditure. In this way these two aspects of monetary policy can be reconciled.

The Baluch, Sunnism and the State in Iran

2017 ◽  
Author(s):  
Stéphane A. Dudoignon
Keyword(s):  
South Asia ◽  
South Asian ◽  
Social Life ◽  
The State ◽  
First Century ◽  
Local Democracy ◽  
Oasis Area ◽  
Shed Light

Since 2002, Sunni jihadi groups have been active in Iranian Baluchistan without managing to plunge the region into chaos. This book suggests that a reason for this, besides Tehran’s military responses, has been the quality of Khomeini and Khamenei’s relationship with a network of South-Asia-educated Sunni ulama (mawlawis) originating from the Sarbaz oasis area, in the south of Baluchistan. Educated in the religiously reformist, socially conservative South Asian Deoband School, which puts the madrasa at the centre of social life, the Sarbazi ulama had taken advantage, in Iranian territory, of the eclipse of Baluch tribal might under the Pahlavi monarchy (1925-79). They emerged then as a bulwark against Soviet influence and progressive ideologies, before rallying to Khomeini in 1979. Since the turn of the twenty-first century, they have been playing the role of a rampart against Salafi propaganda and Saudi intrigues. The book shows that, through their alliance with an Iranian Kurdish-born Muslim-Brother movement and through the promotion of a distinct ‘Sunni vote’, they have since the early 2000s contributed towards – and benefitted from – the defence by the Reformist presidents Khatami (1997-2005) and Ruhani (since 2013) of local democracy and of the minorities’ rights. They endeavoured to help, at the same time, preventing the propagation of jihadism and Sunni radicalisation to Iran – at least until the ISIS/Daesh-claimed attacks of June 2017, in Tehran, shed light on the limits of the Islamic Republic’s strategy of reliance on Deobandi ulama and Muslim-Brother preachers in the country’s Sunni-peopled peripheries.

Narratology

2019 ◽  
Author(s):  
Genevieve Liveley
Keyword(s):  
Reader Response ◽  
Literary Theory ◽  
Chicago School ◽  
Reception History ◽  
First Century ◽  
Unreliable Narrator ◽  
Affect And Cognition ◽  
History Of ◽  
Ars Poetica

This book explores the extraordinary contribution that classical poetics has made to twentieth- and twenty-first-century theories of narrative. Its aim is not to argue that modern narratologies simply present ‘old wine in new wineskins’, but to identify the diachronic affinities shared between ancient and modern stories about storytelling, recognizing that modern narratologists bring particular expertise to bear upon ancient literary theory and offer valuable insights into the interpretation of some notoriously difficult texts. By interrogating ancient and modern narratologies through the mutually imbricating dynamics of their reception it aims to arrive at a better understanding of both. Each chapter selects a key moment in the history of narratology on which to focus, zooming in from an overview of significant phases to look at core theories and texts—from the Russian formalists, Chicago school neo-Aristotelians, through the prestructuralists, structuralists, and poststructuralists, to the latest unnatural and antimimetic narratologists. The reception history that thus unfolds offers some remarkable plot twists. It unmasks Plato as an unreliable narrator and theorist, and offers a rare glimpse of Aristotle putting narrative theory into practice in the role of storyteller in his work On Poets. In Horace’s Ars Poetica and in the works of ancient scholia critics and commentators it locates a rhetorically conceived poetics and a sophisticated reader-response-based narratology evincing a keen interest in audience affect and cognition—and anticipating the cognitive turn in narratology’s mot recent postclassical phase.

Finding the Enemy

2013 ◽  
pp. 473-492
Author(s):  
Frank Russell
Keyword(s):  
Fourth Century ◽  
Border Security ◽  
First Century ◽  
Military Intelligence ◽  
Hellenistic Greece

This chapter analyzes tactical intelligence, following a division by posture: offensive and mobile, and defensive or localized. There was an increase in the use of vanguards among the Greeks after the fourth century BC and among the Romans in the first. Cavalry widely used in this role. The role of reconnaissance in border security is then evaluated. It is noted that the speculatores who accompanied the legions left the field for the office sometime in the first century AD. Greek military intelligence never became professionalized, and did not ponder the sophistication of the prototypical organizations fielded by the tyrants of Cyprus and Sicily in the fourth century. Professionalism and unit identification in intelligence came neither to the poleis nor the kingdoms of Classical or Hellenistic Greece, and came finally to the Romans at least a century after they had pervaded the legions.

scholarly journals Corporate headquarters in the twenty-first century: an organization design perspective

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Sven Kunisch ◽  
Markus Menz ◽  
David Collis
Keyword(s):  
Twentieth Century ◽  
Organization Design ◽  
Business Environment ◽  
First Century ◽  
Future Research ◽  
Corporate Headquarters ◽  
Special Collection ◽  
Design Perspective ◽  
Twenty First Century

Abstract The corporate headquarters (CHQ) of the multi-business enterprise, which emerged as the dominant organizational form for the conduct of business in the twentieth century, has attracted considerable scholarly attention. As the business environment undergoes a fundamental transition in the twenty-first century, we believe that understanding the evolving role of the CHQ from an organization design perspective will offer unique insights into the nature of business activity in the future. The purpose of this article, in keeping with the theme of the Journal of Organization Design Special Collection, is thus to invigorate research into the CHQ. We begin by explicating four canonical questions related to the design of the CHQ. We then survey fundamental changes in the business environment occurring in the twenty-first century, and discuss their potential implications for CHQ design. When suitable here we also refer to the contributions published in our Special Collection. Finally, we put forward recommendations for advancements and new directions for future research to foster a deeper and broader understanding of the topic. We believe that we are on the cusp of a change in the CHQ as radical as that which saw its initial emergence in the late nineteenth/early twentieth century. Exactly what form that change will take remains for practitioners and researchers to inform.

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