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161.
Badini Lorenzo Ott Stephan Aondio Patrik Winter Stefan 《Bulletin of Earthquake Engineering》2022,20(11):5963-6006
Bulletin of Earthquake Engineering - In this study a timber-based integrated solution is presented to solve at once common issues affecting typical reinforced concrete (RC) existing buildings, such... 相似文献
162.
Katherine L. Maier Andrea Fildani Charles K. Paull Timothy R. McHargue Stephan A. Graham David W. Caress 《Sedimentology》2013,60(4):935-960
The Lucia Chica channel system is an avulsion belt with four adjacent channels that progressively avulsed to the north‐east from a single, upslope feeder channel. Avulsion occurred from underfilled channels, leaving open channels that were reactivated by flows stripped from younger, adjacent channels. Differences in relief (height from channel thalweg to levée crest), sinuosity and levée stratigraphy between adjacent channels correspond to relative channel age, and indicate a change in channel morphology and architecture with time. Potential triggers for the change over time include differences in gradient, flow behaviour and characteristics, and channel evolution. Gradient does not appear to be a major control on channel formation and avulsion because adjacent channels formed on the same gradient. Based on available ultra‐high‐resolution remote imaging obtained with an Autonomous Underwater Vehicle, differences in adjacent channel morphology are interpreted to be primarily a result of differences in channel maturity. The interpreted sequence of channel maturity involves erosional channel inception through scouring and incipient channels (defined by linear trains of scours) prior to development of continuous thalwegs. Channel narrowing, formation and growth of levées, increasing channel relief and development of sinuosity occurred as channels evolved. The evolutionary sequence interpreted from the high‐resolution Lucia Chica dataset provides a unique perspective on intrinsic controls of architecture for single channel elements. In addition to helping bridge the gap between outcrop and industry‐standard reflection‐seismic data resolutions and scopes, interpretations in this study also expose potential problems with hierarchical classifications in three‐dimensional imaging of distributary systems, and provide potentially important analogues for evolutionary morphologies not resolved in other deep‐water channel systems. 相似文献
163.
Markus Eckerstorfer Hanne H. Christiansen Stephan Vogel Lena Rubensdotter 《地球表面变化过程与地形》2013,38(5):466-476
Snow cornices grow extensively on leeward edges of plateau mountains in central Svalbard. A dominant wind direction, a snowdrift source area and a sharp slope transition largely control the formation of snow cornices in a barren peri‐glacial landscape. Seasonal snow cornice dynamics control bedrock weathering and erosion in sedimentary bedrock on the Gruvefjellet plateau edge in the valley Longyeardalen. Air, snow and ground temperature sensors, as well as automatic time‐lapse cameras on a leeward facing plateau edge were used to study seasonal cornice dynamics. These techniques allowed for monitoring of cornice accretion, deformation and collapse/melting in great detail. The active layer of the top plateau edge is characterized by high moisture content due to rain before freeze‐up in autumn and cornice meltdown during spring thaw. Thus frost weathering there can be very efficient in this otherwise cold and dry environment. Within the first autumn snowstorms, a vertical fully developed cornice was in place (190 cm thick). The backwall surface beneath the thickest part of the cornice remained in the ice segregation ‘frost cracking window’ for almost nine months. Highly weathered rock material from the plateau edge is thus incorporated into the cornice during cornice accretion. Brittle snow deformation leads to the opening of cornice tension cracks between the cornice mass and the snowpack on the plateau. These cracks are a prerequisite for cornice collapses, and often trigger cornice fall avalanches on the slope beneath. In these open cornice tension cracks, weathered rock debris, plucked from the plateau edge, can be visible, demonstrating the erosional property of the cornices. The cornice will either collapse or melt, resulting in suspended sediment transport downslope by cornice fall avalanche or release as rock fall respectively. Therefore, cornices both promote and trigger high weathering rates on Gruvefjellet, and thus control presently the development of the rockwall free faces and the talus cones. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
164.
Earth System Mass Transport Mission (e.motion): A Concept for Future Earth Gravity Field Measurements from Space 总被引:1,自引:0,他引:1
I. Panet J. Flury R. Biancale T. Gruber J. Johannessen M. R. van den Broeke T. van Dam P. Gegout C. W. Hughes G. Ramillien I. Sasgen L. Seoane M. Thomas 《Surveys in Geophysics》2013,34(2):141-163
In the last decade, satellite gravimetry has been revealed as a pioneering technique for mapping mass redistributions within the Earth system. This fact has allowed us to have an improved understanding of the dynamic processes that take place within and between the Earth’s various constituents. Results from the Gravity Recovery And Climate Experiment (GRACE) mission have revolutionized Earth system research and have established the necessity for future satellite gravity missions. In 2010, a comprehensive team of European and Canadian scientists and industrial partners proposed the e.motion (Earth system mass transport mission) concept to the European Space Agency. The proposal is based on two tandem satellites in a pendulum orbit configuration at an altitude of about 370 km, carrying a laser interferometer inter-satellite ranging instrument and improved accelerometers. In this paper, we review and discuss a wide range of mass signals related to the global water cycle and to solid Earth deformations that were outlined in the e.motion proposal. The technological and mission challenges that need to be addressed in order to detect these signals are emphasized within the context of the scientific return. This analysis presents a broad perspective on the value and need for future satellite gravimetry missions. 相似文献
165.
166.
Stephan Schulz Christian Siebert Tino Rödiger Marwan M. Al-Raggad Ralf Merz 《Environmental Earth Sciences》2013,69(2):605-615
Pollution and overexploitation of scarce groundwater resources is a serious problem in the Zarqa River catchment, Jordan. To estimate this resource’s potential, the amount and spatial distribution of groundwater recharge was calculated by applying the hydrological model J2000. The simulation period is composed of daily values gathered over a 30-year period (July 1977 to June 2007). The figure finally obtained for estimated groundwater recharge of the Zarqa River catchment is 105 × 106 m3 per year (21 mm a?1). This is 19 % higher than the value previously assumed to be correct by most Jordanian authorities. The average ratio of precipitation to groundwater recharge is 9.5 %. To directly validate modelled groundwater recharge, two independent methods were applied in spring catchments: (1) alteration of stable isotope signatures (δ18O, δ2H) between precipitation and groundwater and (2) the chloride mass balance method. Recharge rates determined by isotopic investigations are 25 % higher, and recharge rates determined by chloride mass balance are 9 % higher than the modelled results for the corresponding headwater catchments. This suggests a reasonably modelled safe yield estimation of groundwater resources. 相似文献
167.
Jason W. Barnes Jacob Bow Jacob Schwartz Robert H. Brown Jason M. Soderblom Alexander G. Hayes Graham Vixie Stéphane Le Mouélic Sebastien Rodriguez Christophe Sotin Ralf Jaumann Katrin Stephan Laurence A. Soderblom Roger N. Clark Bonnie J. Buratti Kevin H. Baines Philip D. Nicholson 《Icarus》2011,216(1):136-140
We report the discovery of organic sedimentary deposits at the bottom of dry lakebeds near Titan’s north pole in observations from the Cassini Visual and Infrared Mapping Spectrometer (VIMS). We show evidence that the deposits are evaporitic, making Titan just the third known planetary body with evaporitic processes after Earth and Mars, and is the first that uses a solvent other than water. 相似文献
168.
B. Christophe L. J. Spilker J. D. Anderson N. André S. W. Asmar J. Aurnou D. Banfield A. Barucci O. Bertolami R. Bingham P. Brown B. Cecconi J. -M. Courty H. Dittus L. N. Fletcher B. Foulon F. Francisco P. J. S. Gil K. H. Glassmeier W. Grundy C. Hansen J. Helbert R. Helled H. Hussmann B. Lamine C. L?mmerzahl L. Lamy R. Lehoucq B. Lenoir A. Levy G. Orton J. Páramos J. Poncy F. Postberg S. V. Progrebenko K. R. Reh S. Reynaud C. Robert E. Samain J. Saur K. M. Sayanagi N. Schmitz H. Selig F. Sohl T. R. Spilker R. Srama K. Stephan P. Touboul P. Wolf 《Experimental Astronomy》2012,34(2):203-242
169.
Dainis Dravins Stephan LeBohec Hannes Jensen Paul D. Nuñez 《New Astronomy Reviews》2012,56(5):143-167
Using kilometric arrays of air Cherenkov telescopes at short wavelengths, intensity interferometry may increase the spatial resolution achieved in optical astronomy by an order of magnitude, enabling images of rapidly rotating hot stars with structures in their circumstellar disks and winds, or mapping out patterns of nonradial pulsations across stellar surfaces. Intensity interferometry (once pioneered by Hanbury Brown and Twiss) connects telescopes only electronically, and is practically insensitive to atmospheric turbulence and optical imperfections, permitting observations over long baselines and through large airmasses, also at short optical wavelengths. The required large telescopes (~10 m) with very fast detectors (~ns) are becoming available as the arrays primarily erected to measure Cherenkov light emitted in air by particle cascades initiated by energetic gamma rays. Planned facilities (e.g., CTA, Cherenkov Telescope Array) envision many tens of telescopes distributed over a few square km. Digital signal handling enables very many baselines (from tens of meters to over a kilometer) to be simultaneously synthesized between many pairs of telescopes, while stars may be tracked across the sky with electronic time delays, in effect synthesizing an optical interferometer in software. Simulated observations indicate limiting magnitudes around mV = 8, reaching angular resolutions ~30 μarcsec in the violet. The signal-to-noise ratio favors high-temperature sources and emission-line structures, and is independent of the optical passband, be it a single spectral line or the broad spectral continuum. Intensity interferometry directly provides the modulus (but not phase) of any spatial frequency component of the source image; for this reason a full image reconstruction requires phase retrieval techniques. This is feasible if sufficient coverage of the interferometric (u, v)-plane is available, as was verified through numerical simulations. Laboratory and field experiments are in progress; test telescopes have been erected, intensity interferometry has been achieved in the laboratory, and first full-scale tests of connecting large Cherenkov telescopes have been carried out. This paper reviews this interferometric method in view of the new possibilities offered by arrays of air Cherenkov telescopes, and outlines observational programs that should become realistic already in the rather near future. 相似文献
170.
T. Dahm D. Becker M. Bischoff S. Cesca B. Dost R. Fritschen S. Hainzl C. D. Klose D. K��hn S. Lasocki Th. Meier M. Ohrnberger E. Rivalta U. Wegler Stephan Husen 《Journal of Seismology》2013,17(1):197-202
Various techniques are utilized by the seismological community, extractive industries, energy and geoengineering companies to identify earthquake nucleation processes in close proximity to engineering operation points. These operations may comprise fluid extraction or injections, artificial water reservoir impoundments, open pit and deep mining, deep geothermal power generations or carbon sequestration. In this letter to the editor, we outline several lines of investigation that we suggest to follow to address the discrimination problem between natural seismicity and seismic events induced or triggered by geoengineering activities. These suggestions have been developed by a group of experts during several meetings and workshops, and we feel that their publication as a summary report is helpful for the geoscientific community. Specific investigation procedures and discrimination approaches, on which our recommendations are based, are also published in this Special Issue (SI) of Journal of Seismology. 相似文献