Etching of random solids: hardening dynamics and self-organized fractality

When a finite volume of an etching solution comes in contact with a disordered solid, a complex dynamics of the solid-solution interface develops. Since only the weak parts are corroded, the solid surface hardens progressively. If the etchant is consumed in the chemical reaction, the corrosion dynamics slows down and stops spontaneously leaving a fractal solid surface, which reveals the latent percolation criticality hidden in any random system. Here we introduce and study, both analytically and numerically, a simple model for this phenomenon. In this way we obtain a detailed description of the process in terms of percolation theory. In particular we explain the mechanism of hardening of the surface and connect it to Gradient Percolation.Comment: Latex, aipproc, 6 pages, 3 figures, Proceedings of 6th Granada Seminar on Computational Physic

De la conciencia humana.

La base de la doctrina dialéctico-materialista de la conciencia es la teoría marxista-leninista del reflejo, los datos de las ciencias referentes a la sociedad y los logros de las ciencias naturales; en primer término la doctrina de Séchenov y Pavlov acerca de la actividad nerviosa superior El materialismo dialéctico considera la conciencia como el reflejo del mundo objetivo en el cerebro humano

Some differences of the in- ternal stratification of functional styles and conversational geners in the modern Arabic language (in comparison with the Russian language)

Внутренняя стратификация функциональных стилей и речевых жанров современного арабского языка отличается значительным своеобразием. Прежде всего, тем, что стилистические средства (тропы и стилистические фигуры) выработаны арабскими лингвистами еще в средние века, причем некоторые из них имеют до сих пор сугубо арабскую специфику. С другой стороны, - в данной стратификации учитывается наличие диглоссии, которая способствует тому, что многие стили и жанры отличаются большей литературной обработанностью, чем в русском языке

The functional-stylistic and structure-graphic interpretation of arabic newspaper head-lines

The Arabic newspaper head-lines have many linguistic and stylistic features: using idiomatic speech phrases, the present-future tense of verbs, subject in the beginning of the sentence, avaibility of numerous head-lines and other features that have impression on readers understanding

Development of the structure of a robotic complex for the rehabilitation of a patient with amputation of the lower limbs

The object of the study is the motor activity of patients with various pathologies of the lower extremities in the process of prosthetics. The subject of the study is the methodsand means of monitoring the motor activity of patients with amputation of the lower extremities. To solve the tasks set in the work, a clinical analysis of gait was used in terms oftemporal, spatial, kinematic, dynamic and energy parameters. The structure of the robotic complex is proposed, which makes it possible to increase the efficiency of adjusting the parameters of the prosthesis by organizing biofeedback, taking into account the individual characteristics of the patient. The use of the structure of the rehabilitation robotic complex proposed by the authors will reduce mechanical loads in the process of finishing operations when creating a lower limb prosthesis. The location of the mass-dimensional blocks of robotic mechanisms in a stationary instrument rack ensures the natural gait of the patient