23 Result(s)
within
Gerhard Schäfer
English
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Article
Open AccessHamiltonian formulation of general relativity and post-Newtonian dynamics of compact binaries
Hamiltonian formalisms provide powerful tools for the computation of approximate analytic solutions of the Einstein field equations. The post-Newtonian computations of the explicit analytic dynamics and motion...
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Article
Open AccessHamiltonian formulation of general relativity and post-Newtonian dynamics of compact binaries
Hamiltonian formalisms provide powerful tools for the computation of approximate analytic solutions of the Einstein field equations. The post-Newtonian computations of the explicit analytic dynamics and motion...
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Article
Evaluation of VOC fluxes at the soil-air interface using different flux chambers and a quasi-analytical approach
Dense nonaqueous-phase liquids (DNAPLs) spilled on the soil migrate vertically depending upon gravity and capillary forces through the unsaturated zone of the porous aquifer, forming a vapour plume. These vola...
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Article
Highly gravity-driven flow of a NAPL in water-saturated porous media using the discontinuous Galerkin finite-element method with a generalised Godunov scheme
In this paper, we develop an implementation of gravity effects within a Global Pressure formulation in a numerical scheme based on the implicit pressure explicit saturation (IMPES) approach. We use the Discont...
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Chapter
Higher Order Post-Newtonian Dynamics of Compact Binary Systems in Hamiltonian Form
The Hamiltonian formalism developed by Arnowitt, Deser, and Misner (ADM) is used to derive and discuss the higher order post-Newtonian dynamics and motion of compact binary systems in general relativity includ...
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Chapter
Hamiltonian Formalism for Spinning Black Holes in General Relativity
A Hamiltonian treatment of gravitationally interacting spinning black holes is presented based on a tetrad generalization of the Arnowitt-Deser-Misner (ADM) canonical formalism of general relativity. The forma...
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Article
S. Kopeikin, M. Efroimsky and G. Kaplan: Relativistic celestial mechanics of the solar system
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Article
Prediction of Vertical DNAPL Vapour Fluxes in Soils Using Quasi-Analytical Approaches: Bias Related to Density-Driven and Pressure-Gradient-Induced Advection
This study focuses on a detailed analysis of the errors introduced by two quasi-analytical approaches based on either Fick’s first law or a combination of Fick’s and Darcy’s laws to evaluate the vapour flux of...
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Chapter
Post-Newtonian Methods: Analytic Results on the Binary Problem
A detailed account is given on approximation schemes to the Einstein theory of general relativity where the iteration starts from the Newton theory of gravity. Two different coordinate conditions are used to r...
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Chapter
Gravitomagnetism in Physics and Astrophysics
Based on general relativity, the article reviews gravitomagnetism in physics and astrophysics. Emphasis is put on observational effects. Accelerated reference frames in flat spacetime are discussed to illumina...
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Article
Gravitomagnetism in Physics and Astrophysics
Based on general relativity, the article reviews gravitomagnetism in physics and astrophysics. Emphasis is put on observational effects. Accelerated reference frames in flat spacetime are discussed to illumina...
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Article
A canonical dynamics view of the Newtonian limit of general relativity
The Newtonian limit of general relativity was Jürgen Ehlers favourite model for limit relations between theories of physics. In this contribution, for the case of isolated systems, the Newtonian limit of gener...
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Chapter
Propagation of Light in the Gravitational Field of Binary Systems to Quadratic Order in Newton's Gravitational Constant
The propagation of light is treated in the postlinear gravitational field of binary systems. The light deflection is calculated to quadratic order in Newton’s gravitational constant and fourth order in the inv...
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Chapter
Binary Black Holes and Gravitational Wave Production: Post-Newtonian Analytic Treatment
Within a post-Newtonian approximation scheme the Einstein field equations are solved for the dynamics of the decaying orbits of binary black holes and the related gravitational wave emission. The black holes a...
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Article
Large Scale Experiment on Transport of Trichloroethylene in a Controlled Aquifer
Pollution by dense non-aqueous phase liquids (DNAPLs) represents a major threat to groundwater resources. In a real case of site contamination, the efficiency of remediation techniques is often limited by a la...
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Chapter and Conference Paper
Gravitational Radiation Theory and Light Propagation
The paper gives an introduction to the gravitational radiation theory of isolated sources and to the propagation properties of light rays in radiative gravitational fields. It presents a theoretical study of t...
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Article
Surfactant Enhanced In Situ Remediation of LNAPL Contaminated Aquifers: Large Scale Studies on a Controlled Experimental Site
A central problem in a real case remediation of an oil contaminated site is the knowledge of the volume and the extent of the pollution. As the estimation of the mass balance, usually based on some point measu...
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Article
BOOK REVIEW: Proceedings of the 14th International Conference on General Relativity and Gravitation, edited by M. Francaviglia, G. Longhi, L. Lusanna, and E. Sorace
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Chapter
Tidal effects in binary star systems
Accelerations in gravitational fields are usually treated as resulting from the gravitational force. The “true” gravitational force, however, is a tidal force which cannot be transformed away by going over to ...
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Chapter and Conference Paper
The Hierarchical Organization of Experiments, a Leading Approach in Engineering Science
Many complex phenomena influence the flow of fluids and the transport of contaminants in the subsurface environment.
