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51.
52.
The crystallographic preferred orientations of a series of experimentally deformed fine-grained albite aggregates were measured by synchrotron source X-ray diffraction. Most samples were deformed and extensively recrystallized by low-temperature recrystallization-accommodated dislocation creep. In axial compression as well as simple shear these samples developed weak but distinct crystallographic preferred orientations consistent with intracrystalline slip on {001}<100>; the sheared samples have a marked asymmetry of the <100> maxima with respect to the shear zone boundaries. One sample was axially compressed by solution precipitation creep; it developed a somewhat different but equally strong preferred orientation, perhaps reflecting crystallographic anisotropy in rates of dissolution and growth. 相似文献
53.
Stephanie Wegscheider Tobias Schneiderhan Alexander Mager Hendrik Zwenzner Joachim Post Günter Strunz 《Natural Hazards》2013,68(1):181-195
Earthquakes and other sudden onset natural disasters require quick and efficient emergency response. Earth observation (EO) data can make a valuable contribution to emergency response efforts if provided within hours and at the most days after the event. Mechanisms like the International Charter Space and Major Disasters and the European GMES Emergency Response Service provide the necessary basis for an efficient and rapid provision of EO data and damage mapping. This paper provides an overview of earthquake damage assessment methodologies, their potential and their limitations in a rapid mapping context and outlines a methodology for casualty estimation. Two case studies—the 2010 Haiti earthquake and the 2011 Van (Turkey) earthquake—are presented, where DLR’s Center for satellite-based crisis information (ZKI) provided rapid damage maps using a team-based visual interpretation approach. Additionally, the application of a casualty estimation method in the immediate aftermath of an earthquake is outlined. 相似文献
54.
R. C. Izaurralde J. R. Williams W. M. Post A. M. Thomson W. B. McGill L. B. Owens R. Lal 《Climatic change》2007,80(1-2):73-90
The soil C balance is determined by the difference between inputs (e.g., plant litter, organic amendments, depositional C)
and outputs (e.g., soil respiration, dissolved organic C leaching, and eroded C). There is a need to improve our understanding
of whether soil erosion is a sink or a source of atmospheric CO2. The objective of this paper is to discover the long-term influence of soil erosion on the C cycle of managed watersheds
near Coshocton, OH. We hypothesize that the amount of eroded C that is deposited in or out of a watershed compares in magnitude
to the soil C changes induced via microbial respiration. We applied the erosion productivity impact calculator (EPIC) model to evaluate the role of erosion–deposition
processes on the C balance of three small watersheds (∼1 ha). Experimental records from the USDA North Appalachian Experimental
Watershed facility north of Coshocton, OH were used in the study. Soils are predominantly silt loam and have developed from
loess-like deposits over residual bedrock. Management practices in the three watersheds have changed over time. Currently,
watershed 118 (W118) is under a corn (Zea mays L.)–soybean (Glycine max [L.] Merr.) no till rotation, W128 is under conventional till continuous corn, and W188 is under no till continuous corn.
Simulations of a comprehensive set of ecosystem processes including plant growth, runoff, and water erosion were used to quantify
sediment C yields. A simulated sediment C yield of 43 ± 22 kg C ha−1 year−1 compared favorably against the observed 31 ± 12 kg C ha−1 year−1 in W118. EPIC overestimated the soil C stock in the top 30-cm soil depth in W118 by 21% of the measured value (36.8 Mg C
ha−1). Simulations of soil C stocks in the other two watersheds (42.3 Mg C ha−1 in W128 and 50.4 Mg C ha−1 in W188) were off by <1 Mg C ha−1. Simulated eroded C re-deposited inside (30–212 kg C ha−1 year−1) or outside (73–179 kg C ha−1 year−1) watershed boundaries compared in magnitude to a simulated soil C sequestration rate of 225 kg C ha−1 year−1 and to literature values. An analysis of net ecosystem carbon balance revealed that the watershed currently under a plow
till system (W128) was a source of C to the atmosphere while the watersheds currently under a no till system (W118 and W188)
behaved as C sinks of atmospheric CO2. Our results demonstrate a clear need for documenting and modeling the proportion of eroded soil C that is transported outside
watershed boundaries and the proportion that evolves as CO2 to the atmosphere. 相似文献
55.
Carbon storage and flow through forest ecosystems are major components of the global carbon cycle. The cycle of carbon is intimately coupled with the cycle of nitrogen and the flow of water through forests. The supply of water for tree growth is determined by climate and soil physical properties. The rate at which nitrogen mineralization occurs depends on climate and the type of carbon compounds with which the nitrogen is associated. Species composition, which is also affected by climate, can greatly influence the composition of carbon compounds and subsequently nitrogen availability. Climate change can therefore have a direct effect on forest ecosystem production and carbon storage through temperature and water limitations, and an indirect effect through the nitrogen cycle by affecting species composition. Model simulations of these interactions show that climate change initiates a complex set of direct and indirect responses that are sensitive to the exact nature of the project climate changes. We show results using four different climate-change projections for a location in northeastern Minnesota. Modeled forest responses to each of these climate projections is different indicating that uncertainties in the climate projections may be amplified further as a result of shifts in balance between positive and negative ecosystem feedbacks. 相似文献
56.
A boundary element method is developed for calculating the flare ship hull slammingproblem.The nonlinear free surface elevation and the linear element assumption are employed.The meth-od has been verified by comparisons with results for the water entry of wedges with various deadriseangles.Numerical results show that the pressure distribution varies greatly with the ship hull with differentcurvilinear equations,and the slamming features are also different.From the numerical simulation,the au-thors found that the structural damage of the flare hull might be caused by the increasing hydrodynamicpressure over an extensive area on the flare when the upper part of the flare comes into contact with water. 相似文献
57.
Theoretical and Applied Climatology - Daily 2-m temperature and precipitation extremes in the Baltic Sea region for the time period of 1965–2005 is studied based on data from the BaltAn65 +... 相似文献
58.
59.
Background
Soil organic carbon (SOC) represents a significant pool of carbon within the biosphere. Climatic shifts in temperature and precipitation have a major influence on the decomposition and amount of SOC stored within an ecosystem and that released into the atmosphere. We have linked net primary production (NPP) algorithms, which include the impact of enhanced atmospheric CO2 on plant growth, to the SOCRATES terrestrial carbon model to estimate changes in SOC for the Australia continent between the years 1990 and 2100 in response to climate changes generated by the CSIRO Mark 2 Global Circulation Model (GCM). 相似文献60.
1 INTRODUCTION Scouring in the bend ways leads to deep sections at the toe of the outer bank of the bend. The presenceof secondary currents and the greater depths at the outer bank cause high velocity along the outer bank.The high velocity and shear stres… 相似文献