Overtopping process and structural safety analyses of the earth-rock fill dam with a concrete core wall by using numerical simulations

Abstract: The stress and deformation of rock-fill dam with asphalt concrete core wall founded on deep overburden is calculated and analyzed by Duncan E-ν model and double-yield-surface model through three-dimensional finite element method. The stress and deformation of dams in water storage period is compared by the two models, the results show that the deformation distribution of dam core via two different models are coincide one another. The horizontal displacement and vertical displacement of rock-fill dam with asphalt concrete core wall by double-yield-surface model is smaller than which by Duncan E-ν model in the period of water storage. Furthermore, the horizontal displacement and vertical displacement by double-yield-surface model, which are close to the practical test data through the deformation via two models are in good agreement. The analysis of core-wall stress via double-yield-surface model is more reasonable than the Duncan E-ν model. The analysis result of resisting hydraulic fracturing of core dams by DuncanE-ν model is coincide which of core dams by double-yield-surface model.

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Searching for Orbits with Minimum Fuel Consumption for Station-Keeping Maneuvers: An Application to Lunisolar Perturbations

Mathematical Problems in Engineering ◽

10.1155/2013/415015 ◽

2013 ◽

Vol 2013 ◽

pp. 1-11 ◽

Cited By ~ 9

Author(s):

Antonio Fernando Bertachini de Almeida Prado

Keyword(s):

Numerical Simulations ◽

Fuel Consumption ◽

Total Variation ◽

The Sun ◽

The Moon ◽

Station Keeping ◽

Third Body ◽

Lunisolar Perturbations ◽

The Earth ◽

New Criterion

The present paper has the goal of developing a new criterion to search for orbits that minimize the fuel consumption for station-keeping maneuvers. This approach is based on the integral over the time of the perturbing forces. This integral measures the total variation of velocity caused by the perturbations in the spacecraft, which corresponds to the equivalent variation of velocity that an engine should deliver to the spacecraft to compensate the perturbations and to keep its orbit Keplerian all the time. This integral is a characteristic of the orbit and the set of perturbations considered and does not depend on the type of engine used. In this sense, this integral can be seen as a criterion to select the orbit of the spacecraft. When this value becomes larger, more consumption of fuel is required for the station keeping, and, in this sense, less interesting is the orbit. This concept can be applied to any perturbation. In the present research, as an example, the perturbation caused by a third body is considered. Then, numerical simulations considering the effects of the Sun and the Moon in a satellite around the Earth are shown to exemplify the method.

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Energetic electron acceleration during magnetic reconnection

10.5194/egusphere-egu2020-1945 ◽

2020 ◽

Author(s):

Huishan Fu

Keyword(s):

Numerical Simulations ◽

Magnetic Reconnection ◽

Magnetic Energy ◽

Energetic Electron ◽

Electron Acceleration ◽

Particle Energy ◽

Acceleration Process ◽

The Earth

<p>During magnetic reconnection, magnetic energy is explosively converted to particle energy and consequently electrons are accelerated to hundreds of keV that are dangerous to spacecraft and astronauts. To date, how and where the acceleration happens during reconnection is still unknown. Also, how efficient can the acceleration be remains a puzzle. Using spacecraft measurements (e.g., Cluster and MMS) and numerical simulations, many attempts have been made to answer these questions during the last twenty years. In this talk, I will briefly review these progresses and then show our recent results in understanding these issues. Specifically, I will (1) report a super-efficient electron acceleration by magnetic reconnection in the Earth&#8217;s magnetotail, during which electron fluxes are enhanced by 10000 times within 30 seconds; (2) discuss the mechanisms leading to super-efficient electron acceleration; (3) report the first evidence of electron acceleration at a reconnecting magnetopause, during which the acceleration process is nonadiabatic; and (4) report electron acceleration in the </p>

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Numerical simulations of hypervelocity impact of asteroid/comet on the Earth

International Journal of Impact Engineering ◽

10.1016/j.ijimpeng.2006.09.012 ◽

2006 ◽

Vol 33 (1-12) ◽

pp. 713-722 ◽

Cited By ~ 4

Author(s):

T. Saito ◽

K. Kaiho ◽

A. Abe ◽

M. Katayama ◽

K. Takayama

Keyword(s):

Numerical Simulations ◽

Hypervelocity Impact ◽

The Earth

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Redox Processes in Early Earth Accretion and in Terrestrial Bodies

Elements ◽

10.2138/gselements.16.3.161 ◽

2020 ◽

Vol 16 (3) ◽

pp. 161-166 ◽

Cited By ~ 2

Author(s):

Kevin Righter ◽

Christopher D. K. Herd ◽

Asmaa Boujibar

Keyword(s):

Numerical Simulations ◽

Liquid Water ◽

Experimental Studies ◽

Early Earth ◽

Redox Processes ◽

Natural Materials ◽

The Earth

The Earth is a unique rocky planet with liquid water at the surface and an oxygen-rich atmosphere, consequences of its particular accretion history. The earliest accreting bodies were small and could be either differentiated and undifferentiated; later larger bodies had formed cores and mantles with distinct properties. In addition, there may have been an overall trend of early reduced and later oxidized material accreting to form the Earth. This paper provides an overview—based on natural materials in our Earthbound sample collections, experimental studies on those samples, and calculations and numerical simulations of differentiation processes—of planetary accretion, core–mantle equilibration, mantle redox processes, and redox variations in Earth, Mars, and other terrestrial bodies.

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The long-term evolution of the main asteroidal belt and the origin of large Mars- and Earth-crossers

International Astronomical Union Colloquium ◽

10.1017/s0252921100031626 ◽

1999 ◽

Vol 173 ◽

pp. 321-323

Author(s):

D. Nesvorný ◽

A. Morbidelli

Keyword(s):

Numerical Simulations ◽

Time Scales ◽

Main Belt ◽

Subsequent Evolution ◽

Chaotic Process ◽

The Earth ◽

Term Evolution ◽

Asteroidal Belt ◽

Near Earth Asteroids

AbstractResults of numerical simulations show that the orbits of asteroids in the inner part of the main belt may gradually, subject to a chaotic process acting on 10-100 Myr time scales, become more elliptic and start intersecting the orbit of Mars. The subsequent evolution of an asteroid having close encounters with Mars frequently leads to the Earth-crossing orbit. This revolutionary scenario of the origin of near-Earth asteroids was quantified by Miglioriniet al.(1998) and here we discuss some of the aspects of this work.

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Numerical simulations of very large impacts on the Earth

Planetary and Space Science ◽

10.1016/j.pss.2005.04.011 ◽

2005 ◽

Vol 53 (12) ◽

pp. 1205-1220 ◽

Cited By ~ 8

Author(s):

Vladimir V. Svetsov

Keyword(s):

Numerical Simulations ◽

The Earth

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Probing Magnetic Fields and Acceleration Mechanisms in Blazar Jets with X-ray Polarimetry

Galaxies ◽

10.3390/galaxies9020037 ◽

2021 ◽

Vol 9 (2) ◽

pp. 37

Author(s):

Fabrizio Tavecchio

Keyword(s):

Particle Acceleration ◽

Magnetic Fields ◽

Numerical Simulations ◽

High Energy ◽

Acceleration Of Particles ◽

Synchrotron Emission ◽

Relativistic Jets ◽

X Ray ◽

The Earth ◽

Shock Fronts

X-ray polarimetry promises us an unprecedented look at the structure of magnetic fields and on the processes at the base of acceleration of particles up to ultrarelativistic energies in relativistic jets. Crucial pieces of information are expected from observations of blazars (that are characterized by the presence of a jet pointing close to the Earth), in particular of the subclass defined by a synchrotron emission extending to the X-ray band (so-called high synchrotron peak blazars, HSP). In this review, I give an account of some of the models and numerical simulations developed to predict the polarimetric properties of HSP at high energy, contrasting the predictions of scenarios assuming particle acceleration at shock fronts with those that are based on magnetic reconnection, and I discuss the prospects for the observations of the upcoming Imaging X-ray Polarimetry Explorer (IXPE) satellite.

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