Brief Extract from the Travels of Athanasius Nikitin, a Native of Twer, edited by Michael W. Charney

This translation of Athanasius Nikitin’s fifteenth century travels to India was originally published in India in the Fifteenth Century Being a Collection of Narratives of Voyages to India, edited by R. H. Major, in 1857. Nikitin appears to have only included information on Burma which he obtained by word of mouth. His brief references to Pegu are provided below. The reference to Pegu has been standardized, as two different spellings were included in the original translation. Edited by Michael W. Charney for the SOAS Bulletin of Burma Research

Viscous tilting and production of vorticity in homogeneous turbulence

Viscous depletion of vorticity is an essential and well known property of turbulent flows, balancing, in the mean, the net vorticity production associated with the vortex stretching mechanism. In this letter, we, however, demonstrate that viscous effects are not restricted to a mere destruction process, but play a more complex role in vorticity dynamics that is as important as vortex stretching. Based on the results from three dimensional particle tracking velocimetry experiments and direct numerical simulation of homogeneous and quasi-isotropic turbulence, we show that the viscous term in the vorticity equation can also locally induce production of vorticity and changes of the orientation of the vorticity vector (viscous tilting)

Small scale aspects of flows in proximity of the turbulent/non-turbulent interface

The work reported below is a first of its kind study of the properties of turbulent flow without strong mean shear in a Newtonian fluid in proximity of the turbulent/non-turbulent interface, with emphasis on the small scale aspects. The main tools used are a three-dimensional particle tracking system (3D-PTV) allowing to measure and follow in a Lagrangian manner the field of velocity derivatives and direct numerical simulations (DNS). The comparison of flow properties in the turbulent (A), intermediate (B) and non-turbulent (C) regions in the proximity of the interface allows for direct observation of the key physical processes underlying the entrainment phenomenon. The differences between small scale strain and enstrophy are striking and point to the definite scenario of turbulent entrainment via the viscous forces originating in strain.Comment: 4 pages, 4 figures, Phys. Fluid

Relativistic Coulomb problem for particles with arbitrary half-integer spin

Using relativistic tensor-bispinorial equations proposed in hep-th/0412213 we solve the Kepler problem for a charged particle with arbitrary half-integer spin interacting with the Coulomb potential.Comment: Misprints are correcte

On the new approach to variable separation in the time-dependent Schr\"odinger equation with two space dimensions

We suggest an effective approach to separation of variables in the Schr\"odinger equation with two space variables. Using it we classify inequivalent potentials $V(x_1,x_2)$ such that the corresponding Schr\" odinger equations admit separation of variables. Besides that, we carry out separation of variables in the Schr\" odinger equation with the anisotropic harmonic oscillator potential $V=k_1x_1^2+k_2x_2^2$ and obtain a complete list of coordinate systems providing its separability. Most of these coordinate systems depend essentially on the form of the potential and do not provide separation of variables in the free Schr\" odinger equation ($V=0$).Comment: 21 pages, latex, to appear in the "Journal of Mathematical Physics" (1995

Superintegrable systems with spin and second-order integrals of motion

We investigate a quantum nonrelativistic system describing the interaction of two particles with spin 1/2 and spin 0, respectively. We assume that the Hamiltonian is rotationally invariant and parity conserving and identify all such systems which allow additional integrals of motion that are second order matrix polynomials in the momenta. These integrals are assumed to be scalars, pseudoscalars, vectors or axial vectors. Among the superintegrable systems obtained, we mention a generalization of the Coulomb potential with scalar potential $V_0=\frac{\alpha}{r}+\frac{3\hbar^2}{8r^2}$ and spin orbital one $V_1=\frac{\hbar}{2r^2}$.Comment: 32 page

Laser-flash-photolysis-spectroscopy: A nondestructive method?

Herein, we report the effect of the laser illumination during the diffuse-reflectance laser-flash-photolysis measurements on the morphological and optical properties of TiO2 powders. A grey-blue coloration of the TiO2 nanoparticles has been observed after intense laser illumination. This is explained by the formation of nonreactive trapped electrons accompanied by the release of oxygen atoms from the TiO2 matrix as detected by means of UV-vis and EPR spectroscopy. Moreover, in the case of the pure anatase sample a phase transition of some TiO2 nanoparticles located in the inner region from anatase to rutile occurred. It is suggested that these structural changes in TiO2 are caused by an energy and charge transfer to the TiO2 lattice.BMBF/13N13350Government of the Russian FederationGlobal Research Laboratory (GRL)/NRF-2014K1A1A204104

New exactly solvable relativistic models with anomalous interaction

A special class of Dirac-Pauli equations with time-like vector potentials of external field is investigated. A new exactly solvable relativistic model describing anomalous interaction of a neutral Dirac fermion with a cylindrically symmetric external e.m. field is presented. The related external field is a superposition of the electric field generated by a charged infinite filament and the magnetic field generated by a straight line current. In non-relativistic approximation the considered model is reduced to the integrable Pron'ko-Stroganov model.Comment: 20 pages, discussion of the possibility to test the model experimentally id added as an Appendix, typos are correcte

<i>Brevundimonas halotolerans</i> sp. nov., <i>Brevundimonas poindexterae</i> sp. nov. and <i>Brevundimonas staleyi</i> sp. nov., prosthecate bacteria from aquatic habitats

Eight strains of Gram-negative, bacteroid-shaped, prosthecate bacteria, isolated from brackish water (MCS24T, MCS17 and MCS35), the marine environment (CM260, CM272 and CM282) and activated sludge (FWC40T and FWC43T), were characterized using a polyphasic approach. Analysis of 16S rRNA gene sequences determined that all strains were affiliated to the alphaproteobacterial genus Brevundimonas, forming three distinct phyletic lineages within the genus. The strains grew best with 5–30 g NaCl l-1 at 20–30 °C. DNA G+C contents for strains MCS24T, FWC40T and FWC43T were between 65 and 67 mol%, in accordance with values reported previously for other species of the genus. Moreover, chemotaxonomic data and physiological and biochemical tests allowed the phenotypic differentiation of three novel species within the genus Brevundimonas, for which the names Brevundimonas halotolerans sp. nov. (type strain MCS24T =LMG 25346T =CCUG 58273T), Brevundimonas poindexterae sp. nov. (type strain FWC40T =LMG 25261T =CCUG 57883T) and Brevundimonas staleyi sp. nov. (type strain FWC43T =LMG 25262T =CCUG 57884T) are proposed

Improved charge carrier separation in barium tantalate composites investigated by laser flash photolysis

Charge carrier dynamics in phase pure Ba5Ta4O15 and in a Ba5Ta4O15–Ba3Ta5O15 composite have been studied by means of diffuse reflectance laser flash photolysis spectroscopy in the presence and absence of an electron donor, in order to reveal the reason for the improved photocatalytic performance of the latter. For the first time the transient absorption of trapped electrons with a maximum at around 650 nm and of trapped holes with a transient absorption maximum at around 310 nm is reported for tantalates. The decay kinetics of the photogenerated charge carriers could be fitted by second order reaction kinetics, and the direct recombination of the trapped electrons with the trapped holes was proven. In the absence of an electron donor, no difference in the decay behavior between the phase pure material and the composite material is found. In the presence of methanol, for the pure phase Ba5Ta4O15 the recombination of the charge carriers could not be prevented and the trapped electrons also recombine with the ˙CH2OH radical formed via the methanol oxidation by the trapped holes. However, in the composite, the electron can be stored in the system, the ˙CH2OH radical injects an electron into the conduction band of the second component of the composite, i.e., Ba3Ta5O15. Thus, the electrons are available for an extended period to induce reduction reactions