On the mathematical modelling of the spectral structure of geomagneticPC1 pulsations via the response of Alfvén's ionospheric resonator     

Karel Prikner  Felix Z. Feygin  Dora S. Fligel 《Studia Geophysica et Geodaetica》1995,39(1):19-36

Summary A method of numerical simulation of the coefficient of reflection of the ionospheric transition layer as a function of frequency is applied to the experimental data related to several series of pearl-type pulsations Pc1 (f = 0.2 – 2 Hz) recorded at the observatories of Kerguelen, Sogra and Nurmijarvi. The inverse problem of modelling, i.e. determining the vertical profiles of ionospheric electron concentration corresponding to the actual experimental situations, was solved approximately. The initial assumption for interpreting the specific nature of the series of Pc1 micropulsations parallel in time was their resonance origin under reflection of the signal at magnetically conjugate ionospheres, Alfvén's resonators, in both of the Earth's hemispheres.  相似文献   

Experimental investigation of factors affecting compressional and shear wave velocities in shale and limestone of Ewekoro formation of Southern Nigeria sedimentary basin     

Adio Olufemi Abatan  Olukayode D. Akinyemi  Joseph A. Olowofela  Godwin A. Ajiboye  Felix Kolawole Salako 《Environmental Earth Sciences》2016,75(22):1442

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A primary natrocarbonatitic association in the Deep Earth     

Felix V. Kaminsky  Igor D. Ryabchikov  Richard Wirth 《Mineralogy and Petrology》2016,110(2-3):387-398

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E. O. Ulrich's „Revision der Paläozoischen Systeme“ — ein Markstein der Stratigraphie als Wissenschaft?     

F. Felix Hahn 《International Journal of Earth Sciences》1912,3(8):544-556

Ohne Zusammenfassung  相似文献   

Water exchange and water quality in the coastal zone in the presence of structures     

Izmail Kantardgi  Felix Mairanovsky  Natalia Sapova 《Coastal Engineering》1995,26(3-4)

The water exchange and water quality around coastal structures are considered by analytical, numerical and experimental methods. Water exchange for a small yacht harbour at the Black Sea coast is discussed as an application example. Physical and numerical experiments were carried out to determine the wave induced current field and to correlate the water exchange inside the area around the harbour mole. A hydraulic approach was applied to estimate the water exchange intensities for typical zones. The proposed mathematical model is an irregular wave-current model which includes the interaction between waves and current and a modified breaking criterion. The evolution of salinity concentration during the experimental investigations shows the water exchange intensity. A satisfactory agreement between calculated and measured concentration evolution was obtained.  相似文献   

On flow in Northwestern Gulf of Alaska,May 1972     

Felix Favorite  W. James Ingraham Jr. 《Journal of Oceanography》1977,33(2):67-81

Southwestward volume transport (referred to 1,500 db) out of the Gulf of Alaska seaward of the continental shelf in May 1972 was 12.5 Sv, and nearly 3/4 of this flow occurred within 50 km of the shelf edge. Mean geostrophic velocities of about 50 cm s^–1 occurred in a band 20 km wide, which extended 500 km along the shelf edge; a maximum velocity of 98 cm s^–1 (nearly 2 knots) was obtained. Bottom flow along the inshore part of the shelf as determined by seabed drifters was generally onshore at 0.5 cm s^–1. Evidence is presented of a large cyclonic gyre on the shelf encompassing the Portlock and Albatross Banks, perturbations in surface flow along the shelf edge, and relations between coastal tidal heights and fluctuations in geopotential topography at the shelf edge.  相似文献   

Production key figures for planning the mining of manganese nodules     

Sebastian Ernst Volkmann  Felix Lehnen 《Marine Georesources & Geotechnology》2018,36(3):360-375

Under the impression of decreasing ore grades and increasing production costs in conventional mining, seafloor minerals came into focus. Having gained a basic understanding of geological settings, there is still a lack of tools to assess and plan future mining projects in the deep-sea. This paper contributes to a mining concept which is inspired by the high-tech farming industry: strip mining. Potential mining fields are identified using image filters in conjunction with hydroacoustic backscatter data and slope angles and are portioned into long, narrow strips. In the framework of the EU-funded Blue Mining project, these methods were applied to a part of the eastern German exploration area, located in the manganese nodule belt of the Clarion Clipperton Zone, Pacific Ocean. Both, the mapping technique and the mining concept presented in this paper can be used in early-stage feasibility studies to derive estimates on production key figures for seafloor manganese nodule mining.  相似文献   

Institutional challenges for resolving conflicts between fisheries and endangered species conservation     

Felix Rauschmayer  Heidi WittmerAugustin Berghöfer 《Marine Policy》2008

Successful species conservation typically results in conflicts between wildlife protection and economic uses of natural resources as in fisheries and aquaculture. This article shows why managing these conflicts require a more comprehensive approach than currently pursued by endangered species conservation programmes. Against the background of several case studies focussing on wildlife conflicts in European waters this article derives two challenges for institutional response: First, the question of mandate—which societal actor initiates management related processes that require multiple actors to collaborate? Second, how can continuous processes of collaboration be sustained?  相似文献   

Kimberlitic sources of super-deep diamonds in the Juina area,Mato Grosso State,Brazil     

Felix V. Kaminsky  Sergei M. Sablukov  Elena A. Belousova  Paulo Andreazza  Mousseau Tremblay  William L. Griffin 《Lithos》2010,114(1-2):16-29

The Juina diamond field, in the 1970–80s, was producing up to 5–6 million carats per year from rich placer deposits, but no economic primary deposits had been found in the area. In 2006–2007, Diagem Inc. discovered a group of diamondiferous kimberlitic pipes within the Chapadão Plateau (Chapadão, or Pandrea cluster), at the head of a drainage system which has produced most of the alluvial diamonds mined in the Juina area. Diamonds from placer deposits and newly discovered kimberlites are identical; they have super-deep origins from the upper-mantle and transition zone. Field observations and petrographic studies have identified crater-facies kimberlitic material at seven separate localities. Kimberlitic material is represented by tuffs, tuffisites and various epiclastic sediments containing chrome spinel, picroilmenite, manganoan ilmenite, zircon and diamond. The diamond grade varies from 0.2–1.8 ct/m³. Chrome spinel has 30–61 wt.% Cr₂O₃. Picroilmenite contains 6–14 wt.% MgO and 0.2–4 wt.% Cr₂O₃. Manganoan ilmenite has less than 3 wt.% MgO and 0.38–1.41 wt.% MnO. The ¹⁷⁶Hf/¹⁷⁷Hf ratio in kimberlitic zircons is 0.028288–0.28295 with ε_Hf = 5.9–8.3, and lies on the average kimberlite trend between depleted mantle and CHUR. The previously known barren and weakly diamondiferous kimberlites in the Juina area have ages of 79–80 Ma. In contrast, zircons from the newly discovered Chapadão kimberlites have a mean ²⁰⁶Pb/²³⁸U age of 93.6 ± 0.4 Ma, corresponding to a time of magmatic activity related to the opening of the southern part of the Atlantic Ocean. The most likely mechanism of the origin of kimberlitic magma is super-deep subduction process that initiated partial melting of zones in lower mantle with subsequent ascent of proto-kimberlitic magma.  相似文献   

Digital world meets urban planet – new prospects for evidence-based urban studies arising from joint exploitation of big earth data,information technology and shared knowledge     

Thomas Esch  Hubert Asamer  Felix Bachofer  Jakub Balhar  Martin Boettcher  Enguerran Boissier 《International Journal of Digital Earth》2020,13(1):136-157

ABSTRACT

The digital transformation taking place in all areas of life has led to a massive increase in digital data – in particular, related to the places where and the ways how we live. To facilitate an exploration of the new opportunities arising from this development the Urban Thematic Exploitation Platform (U-TEP) has been set-up. This enabling instrument represents a virtual environment that combines open access to multi-source data repositories with dedicated data processing, analysis and visualisation functionalities. Moreover, it includes mechanisms for the development and sharing of technology and knowledge. After an introduction of the underlying methodical concept, this paper introduces four selected use cases that were carried out on the basis of U-TEP: two technology-driven applications implemented by users from the remote sensing and software engineering community (generation of cloud-free mosaics, processing of drone data) and two examples related to concrete use scenarios defined by planners and decision makers (data analytics related to global urbanization, monitoring of regional land-use dynamics). The experiences from U-TEP’s pre-operations phase show that the system can effectively support the derivation of new data, facts and empirical evidence that helps scientists and decision-makers to implement improved strategies for sustainable urban development.  相似文献