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91.
92.
Prof. Dr. Ida Valeton 《Contributions to Mineralogy and Petrology》1965,11(3):217-246
Zusammenfassung Um einen ersten Überblick zu schaffen, wurden 8 Profile aus den Unterkreide-Bauxiten Südfrankreichs untersucht. Diese Bauxite haben sich durch autochthone Bodenbildung auf sedimentdren Tonen, die ihrerseits verkarsteten Kalken aufliegen, gebildet. Bei der Bauxitisierung der Tonsedimente fand sowohl eine vertikale Stoffdifferenzierung durch Bodenhorizontbildung wie eine horizontale Faziesdifferenzierung durch standortsabhängige Milieuunterschiede statt. Vertikale wie horizontale Anderungen von Gefügeeigenschaften, Chemismus und Mineralzusammensetzung sind das Abbild selektiver Lösungs- und Fallungsvorgange. Es sei ausdrücklich betont, daß es sich um die ersten Ergebnisse an Einzelprofilen handelt. Darüber hinaus herrschen in jedem Faziesraum fur rich wieder sehr differenzierte Bilder, deren heute fixierte Dynamik zu erfassen eine zukünftige Aufgabe sei.
8 sections of bauxites from the Lower Cretaceous in southern France have been investigated in order to get a general view. The bauxites have originated by autochthonous soil formation on sedimentary clays, which lie on top of limestones with a karst topography. When the clay sediments were transformed into bauxites a vertical differentiation by formation of soil horizons took place as well as a horizontal differentiation in consequence of local differences of physical and chemical conditions. Vertical as well as horizontal variations of fabric, chemistry and mineral composition represent the selective processes of solution and precipitation by groundwater circulation.相似文献
93.
Ida Bülow Gregersen Hjalte Jomo Danielsen Sørup Henrik Madsen Dan Rosbjerg Peter Steen Mikkelsen Karsten Arnbjerg-Nielsen 《Climatic change》2013,118(3-4):783-797
Climate change is expected to influence the occurrence and magnitude of rainfall extremes and hence the flood risks in cities. Major impacts of an increased pluvial flood risk are expected to occur at hourly and sub-hourly resolutions. This makes convective storms the dominant rainfall type in relation to urban flooding. The present study focuses on high-resolution regional climate model (RCM) skill in simulating sub-daily rainfall extremes. Temporal and spatial characteristics of output from three different RCM simulations with 25 km resolution are compared to point rainfall extremes estimated from observed data. The applied RCM data sets represent two different models and two different types of forcing. Temporal changes in observed extreme point rainfall are partly reproduced by the RCM RACMO when forced by ERA40 re-analysis data. Two ECHAM forced simulations show similar increases in the occurrence of rainfall extremes of over a 150-year period, but significantly different changes in the magnitudes. The physical processes behind convective rainfall extremes generate a distinctive spatial inter-site correlation structure for extreme events. All analysed RCM rainfall extremes, however, show a clear deviation from this correlation structure for sub-daily rainfalls, partly because RCM output represents areal rainfall intensities and partly due to well-known inadequacies in the convective parameterization of RCMs. The results highlight the problem urban designers are facing when using RCM output. The paper takes the first step towards a methodology by which RCM performance and other downscaling methods can be assessed in relation to the simulation of short-duration rainfall extremes. 相似文献
94.
Yoshiaki Fujii 《Journal of Atmospheric and Solar》2011,73(5-6):643-652
This study suggests that the cause of the stagnation in global warming in the mid 20th century was the atmospheric nuclear explosions detonated between 1945 and 1980. The estimated GST drop due to fine dust from the actual atmospheric nuclear explosions based on the published simulation results by other researchers (a single column model and Atmosphere-Ocean General Circulation Model) has served to explain the stagnation in global warming. Atmospheric nuclear explosions can be regarded as full-scale in situ tests for nuclear winter. The non-negligible amount of GST drop from the actual atmospheric explosions suggests that nuclear winter is not just a theory but has actually occurred, albeit on a small scale. The accuracy of the simulations of GST by IPCC would also be improved significantly by introducing the influence of fine dust from the actual atmospheric nuclear explosions into their climate models; thus, global warming behavior could be more accurately predicted. 相似文献
95.
Serena Ceola Alberto Montanari Tobias Krueger Fiona Dyer Heidi Kreibich Ida Westerberg 《水文科学杂志》2013,58(16):2803-2817
ABSTRACTWe explore how to address the challenges of adaptation of water resources systems under changing conditions by supporting flexible, resilient and low-regret solutions, coupled with on-going monitoring and evaluation. This will require improved understanding of the linkages between biophysical and social aspects in order to better anticipate the possible future co-evolution of water systems and society. We also present a call to enhance the dialogue and foster the actions of governments, the international scientific community, research funding agencies and additional stakeholders in order to develop effective solutions to support water resources systems adaptation. Finally, we call the scientific community to a renewed and unified effort to deliver an innovative message to stakeholders. Water science is essential to resolve the water crisis, but the effectiveness of solutions depends, inter alia, on the capability of scientists to deliver a new, coherent and technical vision for the future development of water systems.
EDITOR D. Koutsoyiannis; ASSOCIATE EDITOR not assigned 相似文献
96.
97.
Satoru Yamamoto Ryosuke Nakamura Tsuneo Matsunaga Yoshiko Ogawa Yoshiaki Ishihara Tomokatsu Morota Naru Hirata Makiko Ohtake Takahiro Hiroi Yasuhiro Yokota Junichi Haruyama 《Icarus》2012,218(1):331-344
The distribution and the geological context of the olivine-rich exposures in the South Pole-Aitken (SPA) Basin on the Moon were investigated based on the spectral data obtained from the Spectral Profiler (SP) and Multiband Imager (MI) onboard the Japanese lunar explorer Kaguya/SELENE. The olivine-rich exposures are found only in the peak rings or central peaks of the Schrödinger basin and Zeeman crater, which are located in the outer region of the SPA Basin and not in the center region. On a localized scale, the olivine-rich materials are exposed on landslide features on the crater walls or sloped wall of the central peaks or the peak rings. Another observational finding is the co-existence of olivine-rich and plagioclase-rich materials on a kilometer scale spanning most of the olivine-rich sites in the Schrödinger basin. Pyroxene-rich materials are found in fresh craters outside the peak rings or the central peaks with olivine-rich materials. Based on these results, the following scenario are proposed: (1) the impact to form the SPA Basin melted a large amount of the lunar upper mantle and crust, and distributed the melted materials to the outer region; (2) local differentiation of melted materials hid the olivine-rich materials in the center region of the SPA Basin; (3) later impacts that formed the Schrödinger and Zeeman craters excavated and exposed the olivine-rich materials to the surface again; and (4) space weathering and regolith gardening obscured the olivine-rich spectra at the exposure sites, but recent, small scale impacts or landslides on the sloped wall exposed fresh olivine-rich materials, allowing the identification of the olivine-rich exposures by spectral remote-sensing. This suggests that several, different scale events play an important role in forming the surface distributions of originally deep-seated materials on the Moon, as well as on other planetary bodies. 相似文献
98.
Adsorption of polar aromatic hydrocarbons on synthetic calcite 总被引:1,自引:0,他引:1
Lene Madsen Laila Grahl-Madsen Christian Grøn Ida Lind John Engell 《Organic Geochemistry》1996,24(12):1151-1155
The wettability of hydrocarbon reservoirs depends on how and to what extent the organic compounds are adsorbed onto the surfaces of calcite, quartz and clay. A model system of synthetic calcite, cyclohexane and the three probe molecules: benzoic acid, benzyl alcohol and benzylamine, have been studied by adsorption experiments. The results clearly demonstrate the differences in the adsorption behaviour between probes with different functional groups of varying polarity and acidity. The maximum adsorption decreases in the order: benzoic acid, benzyl alcohol and benzylamine. The order of magnitude of ΔG° for the adsorption process implies the formation of a strong bond between the calcite surface and the adsorbate molecules. 相似文献
99.
Ida Valeton 《Contributions to Mineralogy and Petrology》1954,4(1-2):207-216
Zusammenfassung Der primare klastische Anteil des mittleren Muschelkalks besitzt ein Maximum in den Korngrößen von 6–20, Ø , das über weite Strecken konstant bleibt. Der Mineralgehalt besteht aus Quarz, Feldspat, Glimmer und vielleieht Kaolinit.Bei der Diagenese warden Quarz und Feldspat teils korrodiert, teils wurden Quarz und Albit neu gebildet. In Randgebieten entstand Glaukonit vermutlich aus Glimmern.Durch Grundwassereinwirkung bildete rich ein zweites Maximum zwischen 0–2 Ø aus. Dabei ist in diesen Korngrößen eine Zunahme an Illit und Kaolinit und das Neuauftreten von Montmorillonit zu verzeichnen.Bei der Verwitterung verschwand das Maximum zwischen 6–20 Ø zugunsten eines Maximums zwischen 0–2 Ø . Damit verschwand auch der primäre Mineralgehalt fast völlig. Die Fraktionen unter 2 Ø setzen sich aus einem illitähnlichen Mineral zusammen.Durch Grundwassertätigkeit und Oberflächenverwitterung wurde also nicht nur der lösliche Anteil des mm ausgelaugt, sondern es sind auch deutliche Veränderungen des klastischen Anteils wahrzunehmen.Herrn Professor Dr.Carl W. Correns zum 60. Geburtstag gewidmet. 相似文献
100.
Yoshiaki Ida 《Physics of the Earth and Planetary Interiors》1975,11(2):147-156
A mathematical model of a sliding system that contains a frictional surface embedded in an elastic specimen and machine is proposed to analyze the frictional behavior observed in laboratory and field. It is shown that stick-slip occurs if the slope of the velocity-stress relation on the sliding surface exceeds a critical value at a certain point between static and kinetic frictions. This condition, coupled with Amontons' law and other subsidiary relations, predicts the effects of normal stress, gouge thickness, temperature, and loading rate etc. on the stick-slip instability, consistent with known experimental evidence. The elastic-wave radiation associated with stick-slip is governed by Brune's source time function, in which rise time and effective stress are proportional to fault dimension and stress drop, respectively. 相似文献