69 research outputs found
Salt Content Distribution and Paleoclimatic Significance of the Lop Nur “Ear” Feature: Results from Analysis of EO-1 Hyperion Imagery
Lop Nur, a playa lake located on the eastern margin of Tarim Basin in northwestern China, is famous for the “Ear” feature of its salt crust, which appears in remote-sensing images. In this study, partial least squares (PLS) regression was used to estimated Lop Nur playa salt-crust properties, including total salt, Ca2+, Mg2+, Na+, Si2+, and Fe2+ using laboratory hyperspectral data. PLS results for laboratory-measured spectra were compared with those for resampled laboratory spectra with the same spectral resolution as Hyperion using the coefficient of determination (R2) and the ratio of standard deviation of sample chemical concentration to root mean squared error (RPD). Based on R2 and RPD, the results suggest that PLS can predict Ca2+ using Hyperion reflectance spectra. The Ca2+ distribution was compared to the “Ear area” shown in a Landsat Thematic Mapper (TM) 5 image. The mean value of reflectance from visible bands for a 14 km transversal profile to the “Ear area” rings was extracted with the TM 5 image. The reflectance was used to build a correlation with Ca2+ content estimated with PLS using Hyperion. Results show that the correlation between Ca2+ content and reflectance is in accordance with the evolution of the salt lake. Ca2+ content variation was consistent with salt deposition. Some areas show a negative correlation between Ca2+ content and reflectance, indicating that there could have been a small-scale temporary runoff event under an arid environmental background. Further work is needed to determine whether these areas of small-scale runoff are due to natural (climate events) or human factors (upstream channel changes
At the Crossroad of the Ancient World : The role of the kingdom of Kroraina on the Silk Roads between the third and fifth centuries CE
This dissertation sets out to study the Silk Road exchange network of late antiquity, seeking a framework for how this wide-reaching phenomenon should be understood. It proposes to do so by a novel bottom-up approach to the Silk Road, conducting a case study of the economic conditions and connections of the kingdom of Kroraina in the Southern Tarim Basin and analysing what role this kingdom might have played in shaping the Silk Road exchange network between the third and the fifth centuries CE. To do so, the study draws upon the uniquely rich source material available from the kingdom of Kroraina, including archaeological material, documents in both Chinese and Sogdian, but most importantly a large collection of 880 locally produced documents in Kharosthi.
Based on these sources, the case study explores various aspects of the economic landscape of Kroraina, considering the evidence for its economic system, the presence and role of long-distance exchange in the kingdom, and the networks in which its oases were situated. Having thus detailed the Krorainan economy, the study turned to questions concerning the Silk Roads, looking first at the form Silk Road exchange might have taken in the Southern Tarim Basin and, secondly, to what extent the kingdoms of the Southern Tarim Basin played a role in facilitating and driving this exchange.
The study concludes that movement and exchange along the Silk Roads through the Southern Tarim Basin in late antiquity was a complex phenomenon, driven by a wide variety of structures, actors, and factors. The study does however show that the kingdom of Kroraina played a crucial role in driving and maintaining this exchange network, both as a consumer of imported goods and as a provider of fundamental infrastructure for movement and trade. Based on these findings the dissertation ends by proposing a layered network model for the Silk Roads network, one that seeks to encompass the full complexity of the Silk Roads network and at the same time emphasise the role of smaller polities in this system.Doktorgradsavhandlin
Earth resources, a continuing bibliography with indexes
This bibliography lists 541 reports, articles and other documents introduced into the NASA scientific and technical information system. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis
Geomorphology from space: A global overview of regional landforms
This book, Geomorphology from Space: A Global Overview of Regional Landforms, was published by NASA STIF as a successor to the two earlier works on the same subject: Mission to Earth: LANDSAT views the Earth, and ERTS-1: A New Window on Our Planet. The purpose of the book is threefold: first, to serve as a stimulant in rekindling interest in descriptive geomorphology and landforms analysis at the regional scale; second, to introduce the community of geologists, geographers, and others who analyze the Earth's surficial forms to the practical value of space-acquired remotely sensed data in carrying out their research and applications; and third, to foster more scientific collaboration between geomorphologists who are studying the Earth's landforms and astrogeologists who analyze landforms on other planets and moons in the solar system, thereby strengthening the growing field of comparative planetology
Three-dimensional magnetotelluric modeling and inversion with applications to the California Basin and Range Province
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1991.Includes bibliographical references.by Randall Lee Mackie.Ph.D
Geology of the coastal lowlands, Boston to Kennebunk, Maine: The 76th annual meeting New England Intercollegiate Geological Conference, Danvers, Massachusetts, October 12-14, 1984
Geologic fieldtrips in Maine and Massachusett
Proceedings of the Geodesy/Solid Earth and Ocean Physics (GEOP) Research Conferences
Papers are presented dealing with interdisciplinary research in the fields of geodesy, solid earth and ocean physics. Topics discussed include: solid earth and ocean tides; the rotation of the earth and polar motion; vertical crustal motions; the geoid and ocean surface; earthquake mechanism; sea level changes; and lunar dynamics
An investigation of the deformation textures of titanium
With the increase in production of titanium in recent years has come a great interest in the mechanical properties and in the possible uses of this metal. Due to the affinity of titanium for oxygen, nitrogen, carbon, and hydrogen, and the market effect of these elements on the mechanical properties, much of the work previously reported is unreliable. As purer commercial grades of titanium and high purity iodide titanium have become available for examination, research has been undertaken to correct and expand the knowledge of the properties of titanium. Although the uses of titanium are limited at the present time, a considerable amount of time and money is being spent to thoroughly exploit its possibilities and it is expected that titanium will soon hold an established position as one of the more important light metals.
A. The problem.
Statement of the problem. This study was undertaken (1) to determine the textures developed in titanium during cold rolling, (2) to determine why the observed textures of titanium differ from those of other hexagonal metals, and (3) to develop a satisfactory explanation of the deformation textures of titanium --Introduction, pages 1-2
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