The Experts below are selected from a list of 34767 Experts worldwide ranked by ideXlab platform
Fritz Aldinger - One of the best experts on this subject based on the ideXlab platform.
-
Equilibrium Configuration of particles in sintering under constraint
Acta Materialia, 2003Co-Authors: Fumihiro Wakai, Fritz AldingerAbstract:Abstract The Equilibrium Configuration of identical particles evolved during sintering was determined by minimizing the sum of surface energy and grain boundary energy for the case where the interparticle distance was constrained. The energy was calculated for the Equilibrium Configuration as functions of the distance between particles. The energy–displacement curve exhibited hysteresis loop at bonding and separation of two particles. The sintering force, a force necessary to just stop the sintering contraction, was calculated from the slope of energy–displacement curve.
Enrique Hernandez Montes - One of the best experts on this subject based on the ideXlab platform.
-
metodo de aproximacion catenaria en el diseno de estructuras antifuniculares
Informes De La Construccion, 2014Co-Authors: Canete M Gueto, Fernandez M Ruiz, Enrique Hernandez MontesAbstract:espanolEste articulo describe una nueva metodologia para resolver un problema tipico del diseno de estructuras antifuniculares: como obtener una configuracion de equilibrio partiendo de condicionantes geometricos iniciales. En los anos 70 se introdujo el Metodo de Densidad de Fuerzas –MDF– para la busqueda de la configuracion de equilibrio, metodo que hoy en dia sigue utilizandose con exito tanto en estructuras tensadas como en estructuras antifuniculares. Sin embargo, en las segundas, el problema de equilibrio se vuelve no-lineal y debe resolverse de una manera iterativa, mediante pruebas sucesivas. A traves del que hemos denominado Metodo de Aproximacion Catenaria –MAC–, concebido como herramienta de ayuda en la aplicacion del MDF a estructuras antifuniculares, es posible obtener de manera sencilla una forma de equilibrio con unas caracteristicas geometricas previamente establecidas. EnglishThis paper describes a new methodology for solving a typical problem in the design of antifunicular structures: how a Equilibrium Configuration can be obtained with initial geometrical constraints. In the seventies the Force Density Method -FDM- was introduced for the research of an Equilibrium position. This method is nowadays being used successfully for both tension structures and antifunicular structures. However, in the second ones, the problem of balance turns non-lineal and must be solved in an iterative manner through successive tests. By means of the so-called Catenary Aproximation Method -CAM, conceived as an assistance tool in the application of the FDM to antifuniculars structures, it is possible to obtain in a simple way a Equilibrium Configuration with some geometric characteristics previously established.
Sumanta Chakraborty - One of the best experts on this subject based on the ideXlab platform.
-
Equilibrium Configuration of perfect fluid orbiting around black holes in some classes of alternative gravity theories
Classical and Quantum Gravity, 2015Co-Authors: Sumanta ChakrabortyAbstract:The hydrodynamic behavior of perfect fluid orbiting around black holes in spherically symmetric spacetime for various alternative gravity theories has been investigated. For this purpose we have assumed a uniform distribution for the angular momentum density of the rotating perfect fluid. The contours of equipotential surfaces are illustrated in order to obtain the nature of inflow and outflow of matter. It has been noticed that the marginally stable circular orbits originating from decreasing angular momentum density lead to closed equipotential surfaces along with cusps, allowing the existence of accretion disks. On the other hand, the growing part of the angular momentum density exhibits central rings for which stable Configurations are possible. However, inflow of matter is prohibited. Among the solutions discussed in this work, the charged F(R) gravity and Einstein–Maxwell–Gauss–Bonnet solutions exhibit inflow and outflow of matter with central rings present. These varied accretion disk structures of perfect fluid attribute astrophysical importance to these spacetimes. The effect of higher curvature terms predominantly arises from the region near the black hole horizon. Hence the structural difference of the accretion disk in modified gravity theories in comparison to general relativity may act as an experimental probe for these alternative gravity theories.
-
Equilibrium Configuration of perfect fluid orbiting around black holes in some classes of alternative gravity theories
arXiv: General Relativity and Quantum Cosmology, 2014Co-Authors: Sumanta ChakrabortyAbstract:The hydrodynamic behaviour of perfect fluid orbiting around black holes in spherically symmetric spacetime for various alternative gravity theories has been investigated. For this purpose we have assumed an uniform distribution for the angular momentum density of the rotating perfect fluid. The contours of equipotential surfaces are illustrated in order to obtain the nature of inflow and outflow of matters. It has been noticed that, the marginally stable circular orbits originating from decreasing angular momentum density lead to closed equipotential surfaces along with cusp allowing existence of accretion disks. On the other hand, the growing part of angular momentum density exhibits central rings for which stable Configurations are possible. However inflow of matter is prohibited. Among the solutions discussed in this work, the charged $F(R)$ gravity and Einstein-Maxwell-Gauss-Bonnet solution exhibit inflow and outflow of matter with central rings present. These varied accretion disk structure of perfect fluid attribute these spacetimes astrophysical importance. The effect of higher curvature terms predominantly arises from region near the black hole horizon. Hence the structural difference of accretion disk in modified gravity theories with comparison to general relativity may act as an experimental probe for these alternative gravity theories.
Peter Schmelcher - One of the best experts on this subject based on the ideXlab platform.
-
adiabatic potential energy surfaces of the h2 ion in a strong magnetic field
Physical Review A, 1996Co-Authors: U Kappes, Peter SchmelcherAbstract:We use a recently established and optimized atomic orbital basis set to perform extensive numerical calculations on the hydrogen molecular ion in a strong magnetic field. Many excited electronic states with gerade and ungerade parity as well as their potential-energy curves are investigated for the perpendicular Configuration, i.e., for orthogonal internuclear and magnetic-field axes. The main issues of our investigation are the local as well as global topological properties of the potential-energy surfaces of the six energetically lowest electronic states of the ${\mathrm{H}}_{2}^{+}$ ion in a strong magnetic field B=1.0 a.u. Our results show the existence of a variety of different possibilities for the topological behavior of the potential-energy surfaces: for the lowest electronic states the global Equilibrium Configuration is either the parallel or the perpendicular Configuration, which are both distinguished by their higher symmetry. As a major result we observe, for the ${3}_{\mathit{u}}$ electronic state, the effect of a global symmetry lowering: the global Equilibrium Configuration of the ${3}_{\mathit{u}}$ potential-energy surface is at \ensuremath{\Theta}=27\ifmmode^\circ\else\textdegree\fi{}, i.e., a Configuration that strongly deviates from the distinct parallel or orthogonal Configurations. Examinations of the electronic probability density distributions with varying angle \ensuremath{\Theta} reveal the origin of the topological behavior of the different surfaces. \textcopyright{} 1996 The American Physical Society.
Canete M Gueto - One of the best experts on this subject based on the ideXlab platform.
-
metodo de aproximacion catenaria en el diseno de estructuras antifuniculares
Informes De La Construccion, 2014Co-Authors: Canete M Gueto, Fernandez M Ruiz, Enrique Hernandez MontesAbstract:espanolEste articulo describe una nueva metodologia para resolver un problema tipico del diseno de estructuras antifuniculares: como obtener una configuracion de equilibrio partiendo de condicionantes geometricos iniciales. En los anos 70 se introdujo el Metodo de Densidad de Fuerzas –MDF– para la busqueda de la configuracion de equilibrio, metodo que hoy en dia sigue utilizandose con exito tanto en estructuras tensadas como en estructuras antifuniculares. Sin embargo, en las segundas, el problema de equilibrio se vuelve no-lineal y debe resolverse de una manera iterativa, mediante pruebas sucesivas. A traves del que hemos denominado Metodo de Aproximacion Catenaria –MAC–, concebido como herramienta de ayuda en la aplicacion del MDF a estructuras antifuniculares, es posible obtener de manera sencilla una forma de equilibrio con unas caracteristicas geometricas previamente establecidas. EnglishThis paper describes a new methodology for solving a typical problem in the design of antifunicular structures: how a Equilibrium Configuration can be obtained with initial geometrical constraints. In the seventies the Force Density Method -FDM- was introduced for the research of an Equilibrium position. This method is nowadays being used successfully for both tension structures and antifunicular structures. However, in the second ones, the problem of balance turns non-lineal and must be solved in an iterative manner through successive tests. By means of the so-called Catenary Aproximation Method -CAM, conceived as an assistance tool in the application of the FDM to antifuniculars structures, it is possible to obtain in a simple way a Equilibrium Configuration with some geometric characteristics previously established.
