26 research outputs found
A ``Tetris''-like model for the Compaction of Dry Granular Media
We propose a two-dimensional geometrical model, based on the concept of
geometrical frustration, conceived for the study of compaction in granular
media. The dynamics exhibits an interesting inverse logarithmic law that is
well known from real experiments. Moreover we present a simple dynamical model
of planes exchanging particles with excluded volume problems, which allows
to clarify the origin of the logarithmic relaxations and the stationary density
distribution. A simple mapping allows us to cast this Tetris-like model in the
form of an Ising-like spin systems with vacancies.Comment: 4 pages, Latex including 2 PS figures (reference corrected). Subm. to
Phys. Rev. Lett. (1997
Electrical and magnetic properties of products of thermal processing of polymethyl vinyl ketone
Iron(II) clathrochelate with an annelated 4,5-dimercapto-[1,3]dithiol-2-thione moiety: Synthesis, structure, and redox reactions
Ground reinforced embankments for rockfall protection: design and evaluation of full scale tests
Infrastructures such as roads and railways as well as urbanised areas, in mountainside regions, can frequently be endangered by rockfalls and, therefore, need to be protected against the impact of rolling blocks. Among the various protection works that can be used, ground reinforced embankments can be considered a feasible technique. A set of full-scale tests on embankments made of ground reinforced by geogrids are presented and discussed. The experiments were performed in a specifically designed and constructed test facility, where concrete blocks up to 9,000 kg in weight were thrown onto a geogrid reinforced embankment at a speed of about 30 m/s. Several embankments made of different geogrid types, different soils and construction layouts were tested at different impact energy levels, permitting a quantitative assessment of the resistance impact of these structures. The experimental results were compared with those obtained from a dynamic finite element method numerical model, and a good agreement was obtaine