Mathematical modelling of the spread of contamination during fires in forests exposed to radioactive contamination

The paper suggested in the context of the general mathematical model of forest fires [1] gives a new mathematical setting and method of numerical solution of a problem of a radioactive spread above the forest region. Numerical solution of problems of radioactive smoke spread during crown fire in exemplified heat energy release in the forest fire front was found. Heat energy release in the forest fire front was found to cause further radioactive particles spread by the action of wind. In the absence of wind, radioactive smoke particles deposit again on the underlying surface after a time. As a wind velocity increases, these particles are transferred in the ground layer over distances proportional to a wind velocity

Experimental study of the thermal stability of materials in high temperature oxygen-containing media

An experimental study is made of the interaction of several materials with a high temperature medium containing oxygen. The temperature of the surface was measured as a function of time. It is found that the higher the velocity of mass removal from the surface, the more effective is the material from the viewpoint of heat resistance

Collective and fractal properties of pion jets in the four-velocity space at intermediate energies

Experimental results are presented for study of collective and fractal properties of soft pion jets in the space of relative four-dimensional velocities. Significant decreasing is obtained for mean square of second particle distances from jet axis for pion-proton interactions at initial energies $\sim 3$ GeV in comparison with hadron-nuclear collisions at close energies. The decreasing results in power dependence of distance variable on collision energy for range $\sim 2 - 4$ GeV. The observation allows us to estimate the low boundary of manifestation of color degree of freedom in pion jet production. Cluster dimension values were deduced for pion jets in various reactions. Fractional values of this dimension indicate on the manifestation of fractal-like properties by pion jets. Changing of mean kinetic energy of jet particles and fractal dimension with initial energy increasing is consistent with suggestion for presence of color degrees of freedom in pion jet production at intermediate energies.Comment: The conference "Physics of fundamental interactions". ITEP, Moscow, Russia. November 23 - 27, 200

POSTERIOR INTEROSSEOUS FLAP IN PEDIATRIC HAND RECONSTRUCTIONS

Purpose: to assess early and long-term results of the pediatric hand reconstructions with posterior interosseous flap, including those in children younger than 3 years old. Materials and methods: results of the hand reconstructions with posterior interosseous artery reverse flap were studied in 10 children (4 males and 6 females) aged from 1 year and 1 month to 13 years old. In 4 cases flap coverage were performed due to acquired posttraumatic hand deformity, in 6 cases reconstruction was assumed for congenital hand deformities. Combined procedures consisted of posterior interosseous artery flap coverage and other types of microsurgical reconstructions were suggested in 4 patients. Preoperative color doppler visualization of the posterior interosseous vessels were mandatory. All flaps were risen under 3.5x-4.5x magnification. Results: all flaps survived completely in 3 weeks postoperatively. There were no postoperative complications such as flap’s arterial or venous insufficiency, deep infection, or posterior interosseous nerve palsy. Nearly whole group (9 of 10) of patients and/or their parents were satisfied with the esthetic view of the reconstructed hand and donor site of the forearm 1 year postoperatively. Conclusion: posterior interosseous flap is a reliable and versatile option in pediatric hand reconstructions, providing excellent skin coverage with good color match and texture. Preservation of major vascular bundles of the forearm (radial and ulnar arteries) during flap harvest gives a possibility to perform a simultaneous microsurgical reconstructions of the hand (e.g. free toe transfer)