Noble gases from the interstellar medium trapped on the MIR space station and analyzed by in vacuo etching

Introduction: The composition of the present interstellar medium (ISM) provides an important benchmark in cosmochemistry. It serves as a reference for galactic chemical evolution (GCE) models, solar mixing predictions and provides information for understanding Big Bang nucleosynthesis. The present-day ISM 3He abundance allows, combined with the protosolar 3He, deduced from the Jovian atmosphere or meteorites [1,2], tracing the GCE over the past 4.56 Ga. 3He/4He = (2.5 0.6) x 10-4 has been determined for the local ISM [3]. However, the uncertainty is too large to better constrain GCE models and - in combination with the present-day solar wind value - the protosolar D/H [4]

Magneto-convective flows around two differentially heated cylinders

Numerical simulations have been carried out in support of an experimental campaign conducted in the MEKKA laboratory at KIT. The aim is investigating liquid metal heat transfer with an imposed magnetic field in a model geometry relevant for the study of water cooled lead lithium blankets for fusion reactors. In the breeding zone of this blanket concept, cooling pipes are immersed in the liquid metal in which convective motion occurs due to significant temperature gradients. The test-section features a rectangular box containing two horizontal cylinders kept at constant differential temperatures in order to establish a temperature gradient that drives the buoyant flow. A magnetic field is applied parallel to gravity. The magneto-convective flow, which results from the presence of electromagnetic forces and temperature gradients in the fluid, is relatively complex, since the liquid metal has to move around the cylinders. For weak magnetic fields, a convective recirculation is fed by a jet-like flow formed by the boundary layers that detach from the pipe walls and recombine behind the obstacles. For sufficiently strong , the thermal field resembles that of a conductive regime with vertical isotherms and the fluid is nearly stagnant in most of the cavity except in layers parallel to magnetic field lines and tangent to the cylinders. The rate of convective heat transfer decreases with an increase of the magnetic field. Numerical simulations complement experimental results and give insight into phenomena that cannot be directly analyzed by means of measured quantities

Effects of Orthogonal Rotating Electric Fields on Electrospinning Process

Electrospinning is a nanotechnology process whereby an external electric field is used to accelerate and stretch a charged polymer jet, so as to produce fibers with nanoscale diameters. In quest of a further reduction in the cross section of electrified jets hence of a better control on the morphology of the resulting electrospun fibers, we explore the effects of an external rotating electric field orthogonal to the jet direction. Through extensive particle simulations, it is shown that by a proper tuning of the electric field amplitude and frequency, a reduction of up to a $30 \%$ in the aforementioned radius can be obtained, thereby opening new perspectives in the design of future ultra-thin electrospun fibres. Applications can be envisaged in the fields of nanophotonic components as well as for designing new and improved filtration materials.Comment: 22 pages, 8 figure

Thermodynamics of the quantum spin-S XXZ chain

The thermodynamics of the spin-$S$ anisotropic quantum $XXZ$ chain with arbitrary value of $S$ and unitary norm, in the high-temperature regime, is reported. The single-ion anisotropy term and the interaction with an external magnetic field in the $z$-direction are taken into account. We obtain, for arbitrary value of $S$, the $\beta$-expansion of the Helmholtz free energy of the model up to order $\beta^6$ and show that it actually depends on $\frac{1}{S(S+1)}$. Its classical limit is obtained by simply taking $S\to \infty$. At $h=0$ and D=0, our high temperature expansion of the classical model coincides with Joyce's exact solution\cite{joyce_prl}. We study, in the high temperature region, some thermodynamic quantities such as the specific heat and the magnetic susceptibility as functions of spin and verify for which values of $S$ those thermodynamic functions behave classically. Their finite temperature behavior is inferred from interpolation of their high- and low-temperature behavior, and shown to be in good agreement with numerical results. The finite temperature behavior is shown for higher values of spin.Comment: 18 pages, 14 figure

can concomitant diseases predict the compliance with cisplatin plus rt in patients with la scchn an exploratory endpoint analysis of the comply trial

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X-ray monitoring of optical novae in M31 from July 2004 to February 2005

Optical novae have recently been identified as the major class of supersoft X-ray sources in M31 based on ROSAT and early XMM-Newton and Chandra observations. This paper reports on a search for X-ray counterparts of optical novae in M31 based on archival Chandra HRC-I and ACIS-I as well as XMM-Newton observations of the galaxy center region obtained from July 2004 to February 2005. We systematically determine X-ray brightness or upper limit for counterparts of all known optical novae with outbursts between November 2003 to the end of the X-ray coverage. In addition, we determine the X-ray brightnesses for counterparts of four novae with earlier outbursts. For comparison with the X-ray data we created a catalogue of optical novae in M31 based on our own nova search programs and on all novae reported in the literature. We collected all known properties and named the novae consistently following the CBAT scheme. We detect eleven out of 34 novae within a year after the optical outburst in X-rays. While for eleven novae we detect the end of the supersoft source phase, seven novae are still bright more than 1200, 1600, 1950, 2650, 3100, 3370 and 3380 d after outburst. One nova is detected to turn on 50 d, another 200 d after outburst. Three novae unexpectedly showed short X-ray outbursts starting within 50 d after the optical outburst and lasting only two to three months. The X-ray emission of several of the novae can be characterized as supersoft from hardness ratios and/or X-ray spectra or by comparing HRC-I count rates with ACIS-I count rates or upper limits. The number of detected optical novae at supersoft X-rays is much higher than previously estimated (>30%). We use the X-ray light curves to estimate the burned masses of the White Dwarf and of the ejecta

Nonlinear Integral Equations for Thermodynamics of the U_{q}(\hat{sl(r+1)}) Perk-Schultz Model

We propose a system of nonlinear integral equations (NLIE) which describes the thermodynamics of the U_{q}(\hat{sl(r+1)}) Perk-Schultz model. These NLIE correspond to a trigonometric analogue of our previous result (cond-mat/0212280), and contain only r unknown functions. In particular, they reduce to Takahashi's NLIE for the XXZ spin chain (cond-mat/0010486) if r=1. We also calculate the high temperature expansion of the free energy. In particular for r=1 case, we have succeeded to derive the coefficients of order O((\frac{J}{T})^{99}).Comment: 19 pages, 4 figures, only the Mathematica file for the high temperature expansion is replaced, to appear in J.Phys.Soc.Jpn.Vol.74 No.3 (2005