Lattice study of the Kink soliton and the zero-mode problem for phi4 in two dimensions

We study the $\lambda\phi^4_{1+1}$ kink solion and the zero-mode contribution to the Kink soliton mass in regions beyond the semiclassical regime. The calculations are done in the non-trivial scaling region and where appropriate the results are compared with the continuum, semiclassical values. We show, as a function of parameter space, where the zero-mode contributions become significant.Comment: 10 pages, LaTeX; typos adde

Collision of a sphere onto a wall coated with a liquid film

Particle-particle and particle-wall collisions occur in many natural and industrial applications such as sedimentation, agglomeration, and granular flows. To accurately predict the behavior of particulate flows, fundamental knowledge of the mechanisms of a single collision is required. In this fluid dynamics video, particle-wall collisions onto a wall coated with 1.5% poly(ethylene-oxide) (PEO) (viscoelastic liquid) and 80% Glycerol and water (Newtonian liquid) are shown.Comment: 1 page, no figure

Clustering and increased settling speed of oblate particles at finite Reynolds number

We study the settling of rigid oblates in quiescent fluid using interface-resolved Direct Numerical Simulations. In particular, an immersed boundary method is used to account for the dispersed solid phase together with lubrication correction and collision models to account for short-range particle-particle interactions. We consider semi-dilute suspensions of oblate particles with aspect ratio AR=1/3 and solid volume fractions $\phi=0.5\%-10\%$. The solid-to-fluid density ratio $R=1.5$ and the Galileo number (i.e. the ratio between buoyancy and viscous forces) based on the diameter of a sphere with equivalent volume $Ga=60$. With this choice of parameters, an isolated oblate falls vertically with a steady wake with its broad side perpendicular to the gravity direction. At this $Ga$, the mean settling speed of spheres is a decreasing function of the volume $\phi$ and is always smaller than the terminal velocity of the isolated particle, $V_t$. On the contrary, we show here that the mean settling speed of oblate particles increases with $\phi$ in dilute conditions and is $33\%$ larger than $V_t$. At higher concentrations, the mean settling speed decreases becoming smaller than the terminal velocity $V_t$ between $\phi=5\%$ and $10\%$. The increase of the mean settling speed is due to the formation of particle clusters that for $\phi=0.5\%-1\%$ appear as columnar-like structures. From the pair-distribution function we observe that it is most probable to find particle-pairs almost vertically aligned. However, the pair-distribution function is non-negligible all around the reference particle indicating that there is a substantial amount of clustering at radial distances between 2 and $6c$ (with $c$ the polar radius of the oblate).Comment: Submitted to Journal of Fluid Mechanic

“Saying Nothing Is Saying Something”:Affective Encounters with the Muslim Other in Amsterdam Public Transport

Taking the Muslim other into consideration, this article investigates Muslims’ everyday encounters within the (im)mobile spaces of public transport that entangle bodies with different histories, backgrounds, and imaginaries. Building on affective atmospheres, I propose an embodied understanding of othering practices and traveling with difference in public transport. Employing (auto)ethnography in Amsterdam, I present public transport as a cross-cultural meeting place with spatial negotiation of difference to study everyday travel experiences of young Muslims. Contributing to the field of mobilities studies, this article bridges the gap in the empirical evidence on the role of public transport, race, and religion in the othering of Muslims

Encountering the Other:everyday Embodied Othering Experiences of Young Muslims in the Netherlands

Whilst the phenomenal growth in ethnic and religious diversity in Western world cities has in recent years been extensively researched and debated within academia and beyond, there is one dimension that is notable for the limited attention it has received to date: the human body. This PhD dissertation sets out to contribute to the emerging study on encountering urban diversity as an inter-corporeal process through Othering. Perhaps the most problematised body in the European context is that of the Muslim, often framed in public discourse and debate as Europe's ultimate Other. Through an urban ethnography in Amsterdam, the study aims to understand how ‘difference’ is lived on the ground by addressing how young Muslims sensorially, corporeally, and affectively experience, feel, and respond to the Othering attached to their bodies within everyday urban spaces of encounter. It will do so by addressing two core questions: how do young Muslims experience Othering?; and how do they respond to Othering? The main contribution of the project lies in its focus on the intersection between religion, race, culture, urbanism, and the body by exploring the ways through which the Muslim Other is (re)constructed and responded to in everyday urban spaces and through mundane urban practices. Focusing on the lived embodied experiences of young Muslims and urban geographies of Othering, the study sheds light on the body-society relationship and provides a better understanding of what it means to be a Muslim in the urban West today

Dynamics of bead formation, filament thinning and breakup in weakly viscoelastic jets

The spatiotemporal evolution of a viscoelastic jet depends on the relative magnitude of capillary, viscous, inertial and elastic stresses. The interplay of capillary and elastic stresses leads to the formation of very thin and stable filaments between drops, or to ‘beads-on-a-string’ structure. In this paper, we show that by understanding the physical processes that control different stages of the jet evolution it is possible to extract transient extensional viscosity information even for very low viscosity and weakly elastic liquids, which is a particular challenge in using traditional rheometers. The parameter space at which a forced jet can be used as an extensional rheometer is numerically investigated by using a one-dimensional nonlinear free-surface theory for Oldroyd-B and Giesekus fluids. The results show that even when the ratio of viscous to inertio-capillary time scales (or Ohnesorge number) is as low as Oh ~ 0.02, the temporal evolution of the jet can be used to obtain elongational properties of the liquid.Akzo Nobel (Firm