Conductance fluctuations in quasi-two-dimensional systems: a practical view

The universal conductance fluctuations of quasi-two-dimensional systems are analyzed with experimental considerations in mind. The traditional statistical metrics of these fluctuations (such as variance) are shown to have large statistical errors in such systems. An alternative characteristic is identified, the inflection point of the correlation function in magnetic field, which is shown to be significantly more useful as an experimental metric and to give a more robust measure of phase coherence.Comment: 9 pages, 7 figure

Extensive population synthesis of isolated neutron stars with field decay

We perform population synthesis studies of different types of neutron stars taking into account the magnetic field decay. For the first time, we confront our results with observations using {\it simultaneously} the Log N -- Log S distribution for nearby isolated neutron stars, the Log N -- Log L distribution for magnetars, and the distribution of radio pulsars in the $P$ -- $\dot P$ diagram. We find that our theoretical model is consistent with all sets of data if the initial magnetic field distribution function follows a log-normal law with $\sim 13.25$ and $\sigma_{\log B_0}\sim 0.6$. The typical scenario includes about 10% of neutron stars born as magnetars, significant magnetic field decay during the first million years of a NS life. Evolutionary links between different subclasses may exist, although robust conclusions are not yet possible. We apply the obtained field distribution and the model of decay to study long-term evolution of neuton stars till the stage of accretion from the interstellar medium. It is shown that though the subsonic propeller stage can be relatively long, initially highly magnetized neutron stars ($B_0 > \sim 10^{13}$ G) reach the accretion regime within the Galactic lifetime if their kick velocities are not too large. The fact that in previous studies made $>$10 years ago, such objects were not considered results in a slight increase of the Accretor fraction in comparison with earlier conclusions. Most of the neutron stars similar to the Magnificent seven are expected to become accreting from the interstellar medium after few billion years of their evolution. They are the main predecestors of accreting isolated neutron stars.Comment: 4 pages, conference "Astrophysics of Neutron Stars - 2010" in honor of M. Ali Alpar, Izmir, Turke

The Theory of SNOM: A Novel Approach

In this paper we consider the application of electromagnetic theory to the analysis of the Scanning Near-field Optical Microscope (SNOM) in order to predict experimentally observable quantities such as the transmission or reflection coefficients for a particular tip-surface configuration. In particular we present the first application of a transfer matrix based calculation to this challenging problem by using an adaptive co-ordinate transformation to accurately model the shape of the SNOM tip. We also investigate the possibility of increasing the transmitted light through the SNOM tip by introducing a metal wire into the centre of the tip. This converts the tip into a co-axial cable. We show that, in principle, this can dramatically improve the transmission characteristics without having a detrimental effect on the resolution.Comment: 19 pages, 11 figures. To be published in the Journal of Modern Optic

Static pressure correction in high Reynolds number fully developed turbulent pipe flow

Measurements are reported of the error in wall static pressure reading due to the finite size of the pressure tapping. The experiments were performed in incompressible turbulent pipe flow over a wide range of Reynolds numbers, and the results indicate that the correction term (as a fraction of the wall stress) continues to increase as the hole Reynolds number $d^+=u_\tau d/\nu$ increases, contrary to previous studies. For small holes relative to the pipe diameter the results follow a single curve, but for larger holes the data diverge from this universal behaviour at a point that depends on the ratio of the hole diameter to the pipe diameter

Design procedure for low-drag subsonic airfoils

Airfoil has least amount of drag under given restrictions of boundary layer transition position, lift coefficient, thickness ratio, and Reynolds number based on airfoil chord. It is suitable for use as wing and propeller aircraft sections operating at subsonic speeds and for hydrofoil sections and blades for fans, compressors, turbines, and windmills

Penrose Diagram for a Transient Black Hole

A Penrose diagram is constructed for a spatially coherent black hole that smoothly begins an accretion, then excretes symmetrically as measured by a distant observer, with the initial and final states described by a metric of Minkowski form. Coordinate curves on the diagram are computationally derived. Causal relationships between space-time regions are briefly discussed. The life cycle of the black hole demonstrably leaves asymptotic observers in an unaltered Minkowski space-time of uniform conformal scale.Comment: 14 pages, 9 figures, spelling correction

Solar Neutrino Matter Effects Redux

Following recent low-threshold analysis of the Sudbury Neutrino Observatory and asymmetry measurements of the BOREXINO Collaboration of the solar neutrino flux, we revisit the analysis of the matter effects in the Sun. We show that solar neutrino data constrains the mixing angle $\theta_{13}$ poorly and that subdominant Standard Model effects can mimic the effects of the physics beyond the Standard Model.Comment: 12 pages of LATEX, 8 figure

Farming with Soybeans For Marketing For Feeding For Land Use

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