A brief history of seismic migration

Geophysics ◽  
2005 ◽  
Vol 70 (3) ◽  
pp. 3MJ-20MJ ◽  
Author(s):  
J. Bee Bednar
Keyword(s):  
Seismic Imaging ◽  
Human Intervention ◽  
Seismic Migration ◽  
Digital Revolution ◽  
Vast Literature ◽  
History Of ◽  
Imaging Theory ◽  
Computer Based ◽  
The 1960S ◽  
Theoretical Developments

In this article, I attempt to focus on the chronology of seismic imaging. I start in the mid-1920s, progress through the human “computer”-based methods of the 1940s and 1950s, discuss the emergence of digital wave-equation technology in the 1960s and early 1970s, and finally end with a review of the present. I include a bit of speculation about the future of seismic imaging, but the meat of the article is on seismic-imaging history. Based on the timing of their publications, I claim there are three key contributors to the theoretical developments of modern seismic imaging: F. Rieber, J. G. Hagedoorn, and J. F. Claerbout. None of these men were the first to consider the seismic-imaging problem, but their papers and algorithms have probably been quoted more often than anyone else's. One certainly must give credit as well to C. H. Dix and M. M. Slotnick for similar contributions. Other names that come to mind include Hans Sattlegger in Germany, A. J. Berkhout in the Netherlands, Bill Schneider at GSI in Dallas, and Robert Stolt at CONOCO in Ponca City, Oklahoma. However, without the independent computational progression predicted by Moore's law (computer speed doubles every 18 months), the spectacular subsurface images produced today would not be possible. I hope to convince the reader that in addition to the development of the vast literature on seismic-imaging theory, another, less-publicized, parallel technological progression has focused on the development of efficient machines to produce, with minimal human intervention, an increasingly more accurate image of the strata below the recording instruments. Unfortunately, with a few key exceptions, the names of many of the contributors to this aspect of seismic imaging have been lost. The digital revolution in the 1960s appears to be the culmination of this attempt at mechanization, but not until the development of truly powerful scientific computers did the more accurate and advanced theoretical developments in seismic-imaging theory become practical to apply and use in the search for diminishing supplies of hydrocarbons. In fact, one can argue that we still don't have sufficient computer power to do everything we need and want to do. But that's another story.

scholarly journals JOHN STUART MILL: LAW, MORALITY, AND LIBERTY

2016 ◽  
Vol 15 (3) ◽  
pp. 879-891 ◽  
Author(s):  
H. S. JONES
Keyword(s):  
Early Modern ◽  
Intellectual History ◽  
Early Modern Period ◽  
John Stuart Mill ◽  
History Of Political Thought ◽  
Cambridge University ◽  
Vast Literature ◽  
History Of ◽  
The 1960S ◽  
The One

Ever since the resurgence of the sub-discipline in the 1960s, the foremost achievements of the history of political thought have dealt with the early modern period. The classics of the genre—Laslett's edition of Locke, Pocock'sMachiavellian Moment, Skinner'sFoundations—have all dealt with that period, and it is hard to think of any works on the nineteenth century that have quite the same stature. Of all the canonical political thinkers, John Stuart Mill is perhaps the one who has proved resistant to the contextualist method. There is a vast literature on Mill, and many historians have written penetratingly about him—Stefan Collini, William Thomas, Donald Winch—but there has hitherto been no historically grounded study of his thought to rival, say, John Dunn on Locke or Skinner on Hobbes, or even a host of learned monographs. Before Varouxakis's book, no study of Mill had been published in Cambridge University Press's flagship series in intellectual history, Ideas in Context. But all that has changed. In these two works, published more or less concurrently, we have two triumphs for contextualism. They demonstrate in impressive detail just why it matters in reading Mill to get the history right.

Droplet deposition in steam turbines

2004 ◽  
Vol 218 (8) ◽  
pp. 859-870 ◽  
Author(s):  
R I Crane
Keyword(s):  
Theoretical Work ◽  
Low Pressure ◽  
Computational Effort ◽  
Steam Turbines ◽  
Work Related ◽  
Low Pressure Turbine ◽  
Fog Deposition ◽  
History Of ◽  
The 1960S ◽  
Theoretical Developments

Research since the 1960s on the deposition of droplets from wet steam is reviewed, concentrating mainly on low-pressure turbines but also covering the limited work related to nuclear high-pressure turbines. The context is first set, outlining the motivation in terms of blade erosion and, to a lesser extent, wetness losses. Details of measurements in turbines and in simulated turbine flows are followed by descriptions of theoretical work on the main inertial and turbulent deposition mechanisms; possible additional contributory mechanisms are summarized. A major combined experimental and computational effort in the 1980s led to broad agreement between measured and calculated fog deposition fractions in low-pressure turbine final stages, attributed largely to the development of more accurate droplet size measurement and computational fluid dynamics techniques. An attempt has been made to correlate advances with the history of steam turbine development and to speculate on the future of deposition studies in the light of recent theoretical developments and trends in power generation.

scholarly journals It’s not only the sea: a history of human intervention in the beach-dune ecosystem of Costa da Caparica (Portugal)

2021 ◽  
Vol 21 (4) ◽  
pp. 227-247
Author(s):  
Monique Palma ◽  
João Alveirinho Dias ◽  
Joana Gaspar Freitas
Keyword(s):  
Environmental History ◽  
Coastal Erosion ◽  
Management Strategies ◽  
Drainage System ◽  
Point Of View ◽  
Human Intervention ◽  
Economic Activities ◽  
History Of ◽  
The 1960S ◽  
The 19Th Century

Costa da Caparica, located south of Lisbon, has been since the 1960s the favourite beach of the population of the Portuguese capital. The bridge over the Tagus river (1966), connecting the two margins, has facilitated the access to that wide beach of sand and dunes. Due to its natural features and proximity to Lisbon, Caparica become a highly populated area, where different social and economic activities compete for the use of the available space, increasing pressure upon the local ecosystems. The situation is even more problematic, because that littoral has been deeply affected by coastal erosion from the 1950s onwards. Authorities have been dealing with the issue using groynes and artificial beach nourishments. Since 2015, the Municipality of Almada is investing in the rehabilitation of the dunes of the beach of S. João, placing fences to retain the sand and planting vegetation. This programme is particularly interesting from a coastal management history point of view, because these dunes have been the object of many interventions with different purposes, but what was done and why is not very well known. The aim of this article is therefore to present the results of a historical research about human intervention in Costa da Caparica and, particularly at S. João beach, starting in the 19th century, with the first dunes’ survey, the afforestation experiences and the construction of a drainage system. This paper offers a long-term perspective on the socio-evolution of these hybrid environments. Results and discussion show how dunes were trimmed by the works carried out and the reasons that laid beneath these. Revealing the ideas and values, the social, economic and political pressures, that across the years and within the same time period, shaped management strategies and landscapes. Keywords: Environmental History; Dunes Rehabilitation; Afforestation; Wetlands; Coastal Erosion.

A note on John Hawkins (1761–1841) and the Hawkins archive

2000 ◽  
Vol 27 (2) ◽  
pp. 261-268
Author(s):  
R. J. CLEEVELY
Keyword(s):  
Major Part ◽  
Reference Lists ◽  
The West ◽  
History Of ◽  
The 1960S

A note dealing with the history of the Hawkins Papers, including the material relating to John Hawkins (1761–1841) presented to the West Sussex Record Office in the 1960s, recently transferred to the Cornwall County Record Office, Truro, in order to be consolidated with the major part of the Hawkins archive held there. Reference lists to the correspondence of Sibthorp-Hawkins, Hawkins-Sibthorp, and Hawkins to his mother mentioned in The Flora Graeca story (Lack, 1999) are provided.

A history of botanical collections in the Luangwa Valley, Zambia

1998 ◽  
Vol 25 (2) ◽  
pp. 283-291
Author(s):  
P.S.M. PHIRI ◽  
D.M. MOORE
Keyword(s):  
Eighteenth Century ◽  
Environmental Impact ◽  
Impact Assessment ◽  
Vascular Plants ◽  
Central Africa ◽  
Peak Activity ◽  
Historical Account ◽  
History Of ◽  
The 1960S ◽  
Made In

Central Africa remained botanically unknown to the outside world up to the end of the eighteenth century. This paper provides a historical account of plant explorations in the Luangwa Valley. The first plant specimens were collected in 1897 and the last serious botanical explorations were made in 1993. During this period there have been 58 plant collectors in the Luangwa Valley with peak activity recorded in the 1960s. In 1989 1,348 species of vascular plants were described in the Luangwa Valley. More botanical collecting is needed with a view to finding new plant taxa, and also to provide a satisfactory basis for applied disciplines such as ecology, phytogeography, conservation and environmental impact assessment.

Islands of Stability: Engaging Emergence from Cellular Automata to the Occupy Movement

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Andrew Pickering
Keyword(s):  
Decision Making ◽  
Cellular Automata ◽  
Black Box ◽  
Collective Decision ◽  
Collective Decision Making ◽  
Occupy Movement ◽  
History Of ◽  
The 1960S

"Instead of considering »being with« in terms of non-problematic, machine-like places, where reliable entities assemble in stable relationships, STS conjures up a world where the achievement of chancy stabilisations and synchronisations is local.We have to analyse how and where a certain regularity and predictability in the intersection of scientists and their instruments, say, or of human individuals and groups, is produced.The paper reviews models of emergence drawn from the history of cybernetics—the canonical »black box,« homeostats, and cellular automata—to enrich our imagination of the stabilisation process, and discusses the concept of »variety« as a way of clarifying its difficulty, with the antiuniversities of the 1960s and the Occupy movement as examples. Failures of »being with« are expectable. In conclusion, the paper reviews approaches to collective decision-making that reduce variety without imposing a neoliberal hierarchy. "

State-run celebration of Liberation Day in Czechoslovakia (based on audiovisual sources)

2019 ◽  
pp. 251-268
Author(s):  
Timur Gimadeev
Keyword(s):  
Political Development ◽  
Communist Regime ◽  
Political Regime ◽  
The Political ◽  
Historical Experience ◽  
History Of ◽  
Post War ◽  
The 1960S ◽  
The Military

The article deals with the history of celebrating the Liberation Day in Czechoslovakia organised by the state. Various aspects of the history of the holiday have been considered with the extensive use of audiovisual documents (materials from Czechoslovak newsreels and TV archives), which allowed for a detailed analysis of the propaganda representation of the holiday. As a result, it has been possible to identify the main stages of the historical evolution of the celebrations of Liberation Day, to discover the close interdependence between these stages and the country’s political development. The establishment of the holiday itself — its concept and the military parade as the main ritual — took place in the first post-war years, simultaneously with the consolidation of the Communist regime in Czechoslovakia. Later, until the end of the 1960s, the celebrations gradually evolved along the political regime, acquiring new ritual forms (ceremonial meetings, and “guards of memory”). In 1968, at the same time as there was an attempt to rethink the entire socialist regime and the historical experience connected with it, an attempt was made to reconstruct Liberation Day. However, political “normalisation” led to the normalisation of the celebration itself, which played an important role in legitimising the Soviet presence in the country. At this stage, the role of ceremonial meetings and “guards of memory” increased, while inventions released in time for 9 May appeared and “May TV” was specially produced. The fall of the Communist regime in 1989 led to the fall of the concept of Liberation Day on 9 May, resulting in changes of the title, date and paradigm of the holiday, which became Victory Day and has been since celebrated on 8 May.

Frontiers of Visibility

Transfers ◽  
2013 ◽  
Vol 3 (2) ◽  
pp. 24-46 ◽  
Author(s):  
Franziska Torma
Keyword(s):  
Twentieth Century ◽  
Current Understanding ◽  
Machine Age ◽  
History Of ◽  
Three Stages ◽  
The 1950S ◽  
The 1960S ◽  
Popular Images ◽  
Cinematic Technology

This article deals with the history of underwater film and the role that increased mobility plays in the exploration of nature. Drawing on research on the exploration of the ocean, it analyzes the production of popular images of the sea. The entry of humans into the depths of the oceans in the twentieth century did not revitalize myths of mermaids but rather retold oceanic myths in a modern fashion. Three stages stand out in this evolution of diving mobility. In the 1920s and 1930s, scenes of divers walking under water were the dominant motif. From the 1940s to the 1960s, use of autonomous diving equipment led to a modern incarnation of the “mermen“ myth. From the 1950s to the 1970s, cinematic technology was able to create visions of entire oceanic ecosystems. Underwater films contributed to the period of machine-age exploration in a very particular way: they made virtual voyages of the ocean possible and thus helped to shape the current understanding of the oceans as part of Planet Earth.

MINING THE ARCHIVES: A POTTERY SEQUENCE FOR BORNO, NIGERIA

2003 ◽  
Vol 1 (1) ◽  
pp. 39-76 ◽  
Author(s):  
Graham Connah ◽  
S.G.H. Daniels
Keyword(s):  
Large Body ◽  
Archaeological Research ◽  
Independent Data ◽  
Frankfurt Am Main ◽  
Archaeological Pottery ◽  
New Findings ◽  
History Of ◽  
1960S And 1970S ◽  
The 1960S ◽  
Johann Wolfgang Goethe

New archaeological research in Borno by the Johann-Wolfgang-Goethe-Universität, Frankfurt am Main, Germany, has included the analysis of pottery excavated from several sites during the 1990s. This important investigation made us search through our old files for a statistical analysis of pottery from the same region, which although completed in 1981 was never published. The material came from approximately one hundred surface collections and seven excavated sites, spread over a wide area, and resulted from fieldwork in the 1960s and 1970s. Although old, the analysis remains relevant because it provides a broad geographical context for the more recent work, as well as a large body of independent data with which the new findings can be compared. It also indicates variations in both time and space that have implications for the human history of the area, hinting at the ongoing potential of broadscale pottery analysis in this part of West Africa and having wider implications of relevance to the study of archaeological pottery elsewhere.

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