Note on dust trapping in inviscid vortex pairs with unequal strengths

We investigate theoretically the motion of tiny heavy passive particles transported in a plane inviscid flow consisting of two point vortices, in order to understand particle dispersion and trapping during vortex interaction. In spite of their large density, particles are not necessarily centrifugated away from vortices. It is observed that they can have various equilibrium positions in the reference frame rotating with the vortices, provided the particle response time and the vortex strength ratio lie in appropriate ranges. A stability analysis reveals that some of these points can be asymptotically stable, and can therefore trap particles released in their basin of attraction. A complete trapping diagram is derived, showing that any vortex pair can potentially become a dust trap, provided the vortex strength ratio is different from 0 (single vortex) and -1 (translating symmetrical vortices). Trapping exists for both co-rotating or contra-rotating vortex pairs. In the latter case, particle trapping on a limit cycle is also observed, and confirmed by using Sapsis and Haller's method [Chaos, 20, 017515, 2010] generalized to non-inertial reference frames

Dynasty as a Patchwork House, or the (Evil) Stepmother: The Example of Zofia Jagiellonka

The significant age difference between Princess Zofia Jagiellonka and her husband had as one advantage for the princess that she had no competitors within her age group (e.g. a stepmother). Moreover, her stepdaughters were approximately the same age and, after her husband’s death, she found herself in similar circumstances to the as a widow. Zofia Jagiellonka eventually resolved the long-standing relationship between her husband and his mistress, knowing in this regard how to defend her social position. She consciously took up the role of mediator among the relatives, and she had a mitigating effect on the tensions between father and son. Her social consciousness included providing for the welfare of the new family by meeting the expectations placed on her with regards to her stepchildren. Her life was not that of the stereotypical “evil stepmother.” Rather, she was someone from whom her stepchildren and others repeatedly sought counsel. Through her royal birth, she was (with regard to her social status) superior to her Guelph relatives, and she had the king—her brother—as her protector. In terms of her relationship to her stepchildren, it was perhaps a great advantage that she herself bore no children, and thus there was no competitive milieu at the court in Wolfenbüttel

GJ 841B - The Second DQ White Dwarf with Polarized CH Molecular Bands

We report a discovery of the circularly polarized CH $A^2\Delta-X^2\Pi$ and $B^2\Sigma^- -X^2\Pi$ molecular bands in the spectrum of the DQ white dwarf GJ 841B. This is only the second such object since the discovery of G99-37 in the 1970s. GJ 841B is also the first WD to unambiguously show polarization in the C_2 Swan bands. By modeling the intensity and circular polarization in the CH bands we determine the longitudinal magnetic field strength of 1.3 +- 0.5 MG and the temperature of 6100 +- 200 K in the absorbing region. We also present new observations of G99-37 and obtain estimates of the magnetic field strength 7.3 +- 0.3 MG and temperature 6200 +- 200 K, in good agreement with previous results.Comment: 10 pages, 3 figure

An H -adaptive finite element compressible flow solver applied to light -gas gun design

The Joint Actinide Shock Physics Experimental Research (JASPER) facility utilizes a two-stage light gas gun to conduct equation of state experiments. The gun has a launch tube bore diameter of 28 mm, and is capable of launching projectiles at a velocity of 7.4 km/s using compressed hydrogen as a propellant. A numerical study is conducted to determine what effects, if any, launch tube exit geometry changes have on attitude of the projectile in flight. A comparison of two launch tube exit geometries is considered. The first case is standard muzzle geometry where the wall of the bore and the outer surface of the launch tube form a 90 degree angle. The second case includes a 26.6 degree bevel transition from the wall of the bore to the outer surface of the launch tube. The finite element method is employed to model the Euler equations and the compressible Navier-Stokes equations. The numerical method incorporates the use of trilinear, hexahedral, isoparametric elements, as well as the use of Petrov-Galerkin weighting applied to the advection terms. Mass lumping allows an explicit Euler scheme to be used in conjunction with a second-order Runge-Kutta approximation to advance the discretized equations in time. An h-adaptive mesh refinement scheme based on elemental flow feature gradients is utilized for greater solution accuracy. For both cases, solutions are calculated for several positions downstream of the launch tube exit. Numerical solutions obtained indicate that both cases will have an adverse effect on flight attitude of the projectile, with the beveled muzzle geometry performing worse than the standard case

Biofilms in porous media: development of macroscopic transport equations via volume averaging with closure for local mass equilibrium conditions

In this work, we upscale a pore-scale description of mass transport in a porous medium containing biofilm to develop the relevant Darcy-scale equations. We begin with the pore-scale descriptions of mass transport, interphase mass transfer, and biologically-mediated reactions; these processes are then upscaled using the method of volume averaging to obtain the macroscale mass balance equations. We focus on the case of local mass equilibrium conditions where the averaged concentrations in the fluid and biological phases can be assumed to be proportional and for which a one-equation macroscopic model may be developed. We predict the effective dispersion tensor by a closure scheme that is solved for the cases of both simple and complex unit cells. The domain of validity of the approach is clearly identified, both theoretically and numerically, and unitless groupings indicating the domain of validity are reported

Valtionmuodostus 1500-luvun Puola-Liettuassa

Arvosteltu teos: Res publica redefined?: The Polish-Lithuanian transition period of the 1560s and 1570s in the context of European state formation processes / Miia Ijäs. [Tampere] : [Miia Ijäs], 2014

Socio-spatial dimensions in energy transitions: Applying the TPSN framework to case studies in Germany

Energy transitions cannot be fully grasped without appreciating their spatial implications. This paper takes up the idea of conceptualizing the socio-spatial dimensions of energy transitions and examines the respective value of the Territory, Place, Scale, and Network (TPSN) framework. The fundamental contribution of this framework is to move the focus of the debate away from whether one ontology of the socio-spatial is ‘better’ than another. By applying the TPSN framework to emblematic cases of regional energy spaces in Germany, we realized that the dynamics of different fields of action within an energy transition are characterized in each case by a specific pattern of the four socio-spatial dimensions and related strategies. The paper concludes with a discussion of the benefits and the shortcomings of the framework as it relates to understanding energy transitions. The fundamental role of place-making at a nexus with territorializations, as well as the additional importance of networking and rescaling strategies, are to be understood with the additional factors of the role of governance spaces, the upscaling of local experiments, powerful space-related discourses, and the socio-materiality of spaces

Detailed Spectroscopic and Photometric Analysis of DQ White Dwarfs

We present an analysis of spectroscopic and photometric data for cool DQ white dwarfs based on improved model atmosphere calculations. In particular, we revise the atmospheric parameters of the trigonometric parallax sample of Bergeron et al.(2001), and discuss the astrophysical implications on the temperature scale and mean mass, as well as the chemical evolution of these stars. We also analyze 40 new DQ stars discovered in the first data release of the Sloan Digital Sky Survey.Comment: 6 pages,3 figures, 14th European Workshop on White Dwarfs, ASP Conference Series, in pres