Rolling Friction in Loose Media and its Role in Mechanics Problems

Rolling friction between particles is to be set in problems of granular material mechanics alongside with sliding friction. A classical problem of material passive lateral pressure on the retaining wall is submitted as a case in point. 3D method of discrete elements was employed for numerical analysis. Material is a universe of spherical particles with specified size distribution. Viscose-elastic properties of the material and surface friction are included, when choosing contact forces. Particles' resistance to rolling relative to other particles and to the boundary is set into the model. Kinetic patterns of medium deformations are given. It has been proved that rolling friction can significantly affect magnitude and nature of passive lateral pressure on the retaining wall

Bichromatic Slowing of Metastable Helium

We examine two approaches for significantly extending the velocity range of the optical bichromatic force (BCF), to make it useful for laser deceleration of atomic and molecular beams. First, we present experimental results and calculations for BCF deceleration of metastable helium using very large BCF detunings, and discuss the limitations of this approach. We consider in detail the constraints, both inherent and practical, that set the usable upper limit of the BCF. We then show that a more promising approach is to utilize a BCF profile with a relatively small velocity range in conjunction with chirped Doppler shifts, to keep the force resonant with the atoms as they are slowed. In an initial experimental test of this chirped BCF method, helium atoms are slowed by $\sim 370$ m/s using a BCF profile with a velocity width of $\lesssim 125$ m/s. Straightforward scaling of the present results indicates that a decelerator for He* capable of loading a magneto-optical trap (MOT) can yield a brightness comparable to a much larger Zeeman slower.Comment: 11 pages, 9 figures. Published in Phys. Rev.

Features of martensitic transformation and fine structure of intermetallic compound Ni50Mn50

Transmission and scanning electron microscopy and Xray and electron diffraction are used to investigate the martensitic transformation and martensitic phase structure of the Ni50Mn50 alloy. Its resistivity and coefficient of thermal expansion are measured over a wide temperature range. © 2013 Pleiades Publishing, Ltd

Non-language factors and language evolution

This paper is devoted to the description of the functioning and development of the language system seen in correlation with the influence of non-language factor

Optical Stern Gerlach Effect beyond the rotating wave approximation

We show that the inclusion of counter rotating terms, usually dropped, in the interaction Hamiltonian of the electric dipole of a two level atom with an electromagnetic field leads to significant modification of the splitting of an atomic beam known as Optical Stern Gerlach Effect which now acquires a fine structure.Comment: 9 pages, 1 figur

Small-scale-field Dynamo

Generation of magnetic field energy, without mean field generation, is studied. Isotropic mirror-symmetric turbulence of a conducting fluid amplifies the energy of small-scale magnetic perturbations if the magnetic Reynolds number is high, and the dimensionality of space d satisfies 2.103 < d <8.765. The result does not depend on the model of turbulence, incompressibility and isotropy being the only requirements.Comment: 11 pages Plain TeX, no figures, Accepted by Phys. Rev. Let