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571.
Accounting for elasto-plastic motion in granular media, hypoplasticity is a state-of-the-art constitutive model derived from data accumulated over many decades. In contrast, GSH, a hydrodynamic theory, is derived from general principles of physics, with comparatively few inputs from experiments, yet sporting an applicability ranging from static stress distribution via elasto-plastic motion to fast dense flow, including non-uniform ones such as a shear band. Comparing both theories, we find great similarities for uniform, slow, elasto-plastic motion. We also find that proportional paths and the Goldscheider rule used to construct barodesy, another, more recent constitutive model, are natural results of GSH’s equations. This is useful as it gives these constitutive relations a solid foundation in physics and, in reverse, GSH a robust connection to reality. The same symbiotic relation exists between GSH and KCR, or Kamrin’s non-local constitutive relation, a model that was successfully employed to account for a wide shear band in split-bottom cells. 相似文献
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Natural Hazards - The return period is a probabilistic criterion used to measure and communicate the random occurrence of geophysical events such as floods in risk assessment studies. Since an... 相似文献
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Paul A. Scowen Mario R. Perez Susan G. Neff Dominic J. Benford 《Experimental Astronomy》2014,37(1):11-35
Following several recommendations presented by the Astrophysics Decadal Survey 2010 centered around the need to define “a future ultraviolet-optical space capability”, on 2012 May 25, NASA issued a Request for Information (RFI) seeking persuasive ultraviolet (UV) and visible wavelength astrophysics science investigations. The goal was to develop a cohesive and compelling set of science objectives that motivate and support the development of the next generation of ultraviolet/visible space astrophysics missions. Responses were due on 10 August 2012 when 34 submissions were received addressing a number of potential science drivers. A UV/visible Mission RFI Workshop was held on 2012 September 20 where each of these submissions was summarized and discussed in the context of each other. We present a scientific analysis of these submissions and presentations and the pursuant measurement capability needs, which could influence ultraviolet/visible technology development plans for the rest of this decade. We also describe the process and requirements leading to the inception of this community RFI, subsequent workshop and the expected evolution of these ideas and concepts for the remainder of this decade. 相似文献
577.
Data collected in 4 years of field observations were used in conjunction with continuous simulation models to study, at the small‐basin scale, the water balance of a closed catchment‐lake system in a semi‐arid Mediterranean environment. The open water evaporation was computed with the Penman equation, using the data set collected in the middle of the lake. The surface runoff was partly measured at the main tributary and partly simulated using a distributed, catchment, hydrological model, calibrated with the observed discharge. The simplified structure of the developed modelling mainly concerns soil moisture dynamics and bedrock hydraulics, whereas the flow components are physically based. The calibration produced high efficiency coefficients and showed that surface runoff is greatly affected by soil water percolation into fractured bedrock. The bedrock reduces the storm‐flow peaks and the interflow and has important multi‐year effects on the annual runoff coefficients. The net subsurface outflow from the lake was calculated as the residual of the lake water balance. It was almost constant in the dry seasons and increased in the wet seasons, because of the moistening of the unsaturated soil. During the years of observation, rainfall 30% higher than average caused abundant runoff and a continuous rise in the lake water levels. The analysis allows to predict that, in years with lower than the average rainfall, runoff will be drastically reduced and will not be able to compensate for negative balance between precipitation and lake evaporation. Such highly unsteady situations, with great fluctuations in lake levels, are typical of closed catchment‐lake systems in the semi‐arid Mediterranean environment. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
578.
The Melinau carbonate platform initiated during the Mid-Eocene on a rotating slice of the Rajang accretionary prism. The differential sedimentary loading enhanced a rotation of the mobile substratum and created an elongated, asymmetrical wedge-top basin. The extensional southern margin of the basin consists of a 2100–2200-m-thick section of Eocene-to-Oligocene carbonates. These thin laterally towards the northern margin of the basin, where a carbonate factory was active on a postulated underlying thrust. Backstepping and dismemberment of the carbonate system started during the latest Oligocene and deep-marine sedimentation became prevalent over the entire region during the Early Miocene. 相似文献
579.
Annama H chondrite—Mineralogy,physical properties,cosmic ray exposure,and parent body history 下载免费PDF全文
Tomáš Kohout Jakub Haloda Patricie Halodová Matthias M. M. Meier Colin Maden Henner Busemann Matthias Laubenstein Marc. W. Caffee Kees C. Welten Jens Hopp Mario Trieloff Ramakant R. Mahajan Sekhar Naik Josep M. Trigo‐Rodriguez Carles E. Moyano‐Cambero Michael I. Oshtrakh Alevtina A. Maksimova Andrey V. Chukin Vladimir A. Semionkin Maksim S. Karabanalov Israel Felner Evgeniya V. Petrova Evgeniia V. Brusnitsyna Victor I. Grokhovsky Grigoriy A. Yakovlev Maria Gritsevich Esko Lyytinen Jarmo Moilanen Nikolai A. Kruglikov Aleksey V. Ishchenko 《Meteoritics & planetary science》2017,52(8):1525-1541
The fall of the Annama meteorite occurred early morning (local time) on April 19, 2014 on the Kola Peninsula (Russia). Based on mineralogy and physical properties, Annama is a typical H chondrite. It has a high Ar‐Ar age of 4.4 Ga. Its cosmic ray exposure history is atypical as it is not part of the large group of H chondrites with a prominent 7–8 Ma peak in the exposure age histograms. Instead, its exposure age is within uncertainty of a smaller peak at 30 ± 4 Ma. The results from short‐lived radionuclides are compatible with an atmospheric pre‐entry radius of 30–40 cm. However, based on noble gas and cosmogenic radionuclide data, Annama must have been part of a larger body (radius >65 cm) for a large part of its cosmic ray exposure history. The 10Be concentration indicates a recent (3–5 Ma) breakup which may be responsible for the Annama parent body size reduction to 30–35 cm pre‐entry radius. 相似文献
580.
Carlo Del Gaudio Mariano Di Domenico Paolo Ricci Gerardo Mario Verderame 《Bulletin of Earthquake Engineering》2018,16(10):4607-4637
On August 21st, 2017, an earthquake with duration magnitude Md?=?4.0 and epicentre in Casamicciola Terme hit Ischia island, in the South of Italy. This event caused two fatalities and dozens of injured people. Moreover, despite the low magnitude, the earthquake produced significant damages to masonry and reinforced concrete (RC) buildings, with some partial or complete collapse of structures, in a very limited area close to the epicentre, while even at small distance from the most damaged zone the earthquake was just felt by local people and tourists. In the days after the event, discussions concerning the destructive effects of such an earthquake arose in the scientific community—as also reported by local and national media. In this paper, the seismic history of Ischia island is recalled to show and explain the peculiarity of the August 21st earthquake, which is also described in terms of ground motion and response spectra characteristics. The results of the first surveys carried out in Casamicciola Terme are reported, together with appropriate pictures, to introduce and explain the observed damage state of masonry and RC buildings in the epicentral zone. Then, data from the 15th general census of the population and dwellings (ISTAT) is used to define vulnerability classes according to the classification of the European Macrosismic Scale (EMS-98) (Grünthal, 1998). Seismic damage scenarios are then evaluated combining macro-seismic intensity values obtained using an interpolation method starting from QUEST macro-seismic survey data (Azzaro et al., 2017 ) and fragility curves for A-to-D vulnerability classes and for five damage states, from DS0 (no damage) to DS5 (collapse) trough a Monte Carlo simulation technique. The distributions of Usable, Temporarily or Partially Unusable, and Unusable buildings, which are obtained by using relationships between damage and usability judgments obtained through post-earthquake damage data collected after past seismic events, result in very good accordance with those published in September 1st, 2017 by the Department of Civil Protection, regarding a dataset of about 600 buildings. 相似文献