Simultaneous conservation of linear momentum and of mechanical energy can be used to calculate the relative speed of an isolated pair of astronomical bodies as a function of the distance separating them. An exact treatment is straightforward and has application to such contemporary topics as the launch velocities of rockets, and collisions between an asteroid and the Earth. In contrast, when th...

seepage analysis through earth dams is employed to determine the water loss. moreover, as the magnitude of pore pressure in dam body is calculated using seepage analysis, this analysis plays an important role on the stability analysis in these types of structures. as the hydraulic conductivity of the earth dam materials, is considered as one of the effective parameters on the magnitude of seepa...

Since the discovery of plate tectonics, geophysicists have sought to understand the dynamic system driving the evolution of the earth, both at the surface and in the deep interior. While the deep earth contains far fewer phases than the crust, the inaccessibility of the mantle and core present a different challenge: unraveling the physical behavior of materials at conditions beyond our intuitiv...

Direct atomic resolution images have been obtained that illustrate how a range of rare-earth atoms bond to the interface between the intergranular phase and the matrix grains in an advanced silicon nitride ceramic. It has been found that each rare-earth atom bonds to the interface at a different location, depending on atom size, electronic configuration, and the presence of oxygen at the interf...

The effects of rare earth addition and hot extrusion process on the grain refinement of magnesium alloy were studied. The as-cast Mg-6Al-1Zn (AZ61) alloy had the average grain size of ~ 64 µm and its microstructure consisted of α-Mg and Mg17Al12 phase. By partial substitution of Al with Gd to reach Mg-4.8Gd-1.2Al-1Zn alloy, it was observed that the Mg17Al12 phase disappeared and two new interme...

Typical earth system models involve coupled model components in high performance computing (HPC) environments. There are two emerging component-based frameworks for developing HPC applications. The Earth System Modeling Framework (ESMF), funded by NASA Earth System Technology Office (ESTO) Computational Technologies (CT) Project, defines a domain specific component interface for earth system mo...

It has been proposed that a long-period stacking ordered (LPSO) structure is responsible for the excellent mechanical properties of lightweight alloys of Mg-Y-RE (RE: rare earth elements) system. In this study, the phenomenological simulation model for describing the formation process of the LPSO structure in Mg­Y­Zn system is constructed by means of the phase-field method. The results obtained...