Multiple equilibria in a simple elastocapillary system

We consider the elastocapillary interaction of a liquid drop placed between two flexible sheets, which are both clamped at one end to a rigid substrate. This is a simple model system relevant to the problem of surface tension-induced collapse of flexible micro-channels that has been observed in the manufacture of microelectromechanical systems(MEMS). We determine the conditions under which the flexible sheets remain separated, touch at a point, or stick along a portion of their length. Surprisingly, we show that in many circumstances multiple equilibrium states are possible. We develop a lubrication-type model for the flow of liquid out of equilibrium and thereby investigate the stability of the multiple equilibria. We demonstrate that for given material properties two stable equilibria may exist and show through numerical solutions of the dynamic model that it is the initial state of the system that determines which stable equilibrium is reached by the system; the system does not simply choose the equilibrium state of lowest energy

Collagen content as a risk factor in breast cancer? A pilot clinical study

A retrospective pilot clinical study on time domain multi-wavelength (635 to 1060 nm) optical mammography was exploited to assess collagen as a breast-cancer risk factor on a total of 109 subjects (53 healthy and 56 with malignant lesions). An increased cancer occurrence is observed on the 15% subset of patients with higher age-matched collagen content. Further, a similar clustering based on the percentage breast density leads to a different set of patients, possibly indicating collagen as a new independent breast cancer risk factor. If confirmed statistically and on larger numbers, these results could have huge impact on personalized diagnostics, health care systems, as well as on basic research

Boundary conditions for free surface inlet and outlet\ud problems

We investigate and compare the boundary conditions that are to be applied to free surface problems involving inlet and outlets of Newtonian fluid, typically found in coating processes. The flux of fluid is a priori known at an inlet, but unknown at an outlet, where it is governed by the local behaviour near the film-forming meniscus. In the limit of vanishing capillary number Ca it is well-known that the flux scales with Ca2/3, but this classical result is nonuniform as the contact angle approaches . By examining this limit we find a solution that is uniformly valid for all contact angles. Furthermore, by considering the far-field behaviour of the free surface we show that there exists a critical capillary number above which the problem at an inlet becomes over-determined. The implications of this result for the modelling of coating flows are discussed

Phase order in superfluid helium films

Classic experimental data on helium films are transformed to estimate a finite-size phase order parameter that measures the thermal degradation of the condensate fraction in the two-dimensional superfluid. The order parameter is found to evolve thermally with the exponent $\beta = 3 \pi^2/128$, a characteristic, in analogous magnetic systems, of the Berezinskii-Kosterlitz-Thouless (BKT) phase transition. Universal scaling near the BKT fixed point generates a collapse of experimental data on helium and ferromagnetic films, and implies new experiments and theoretical protocols to explore the phase order. These results give a striking example of experimental finite-size scaling in a critical system that is broadly relevant to two-dimensional Bose fluids.Comment: 6 pages, 2 figure

Asymptotic solutions of glass temperature profiles during steady optical fibre drawing

In this paper we derive realistic simplified models for the high-speed drawing of glass optical fibres via the downdraw method, that capture the fluid dynamics and heat transport in the fibre via conduction, convection and radiative heating. We exploit the small aspect ratio of the fibre and the relative orders of magnitude of the dimensionless parameters that characterize the heat transfer to reduce the problem to one- or two-dimensional systems via asymptotic analysis. The resulting equations may be readily solved numerically and in many cases admit exact analytic solutions. The systematic asymptotic breakdown presented is used to elucidate the relative importance of furnace temperature profile, convection, surface radiation and conduction in each portion of the furnace and the role of each in controlling the glass temperature.\ud \ud The models derived predict many of the qualitative features observed in the real industrial process, such as the glass temperature profile within the furnace and the sharp transition in fibre thickness. The models thus offer a desirable route to quick scenario testing, providing valuable practical information into the dependencies of the solution on the parameters and the dominant heat-transport mechanism

A theoretical analysis of inertia-like switching in magnets: applications to a synthetic antiferromagnet

The magnetization dynamics of a synthetic antiferromagnet subject to a short magnetic field pulse, has been studied by using a combination of first-principles and atomistic spin dynamics simulations. We observe switching phenomena on the time scale of tens of picoseconds, and inertia-like behavior in the magnetization dynamics. We explain the latter in terms of a dynamic redistribution of magnetic energy from the applied field pulse to other possible energy terms, such as the exchange interaction and the magnetic anisotropy, without invoking concepts such as inertia of an antiferromagnetic vector. We also demonstrate that such dynamics can also be observed in a ferromagnetic material where the incident field pulse pumps energy to the magnetic anisotropy

Measurement of the lepton charge asymmetry in inclusive W production in pp collisions at √s = 7TeV at the CMS experiment

Lepton charge asymmetry in inclusive pp → WX production at s = 7TeV has been measured by the CMS detector at the LHC, using 36 pb−1 of data. These measurements, performed in both W → eν and W → μν channels, provide new insights into proton structure functions

The Impact of Union Citizenship upon Rights to Family Reunification: An Analysis of the Residence Rights of Family Members within the UK

This thesis explores the link between the residence rights of Union citizens and their family members and the Court of Justice of the European Union’s development of the concept of Union citizenship. The Court has not approached this development in a predictable or linear fashion, and the cementing of Union citizenship as a status capable of leading to residence rights in the form of Directive 2004/38 made the continuation of a flexible and expansive approach more difficult. This thesis examines the UK’s implementation of both the Citizens’ Directive and other EU sources of rights of residence and compares the rights of UK citizens with links to EU law to those without any possibility of relying on EU provisions within the UK. It is contended that Union citizenship has had a greater impact upon rights of residence for Union citizens and their family members than would have been anticipated from either the Treaty provisions or Directive 2004/38. The importance of EU rights of residence is particularly high in the UK, given the stringent requirements of the Immigration Rules concerning non-EU immigration. Treaty rights can circumvent restrictive UK provisions, and the approach of the UK judiciary in applying EU concepts in cases concerning the UK Immigration Rules is important in this respect. The fundamental rights implications of the Lisbon Treaty are assessed, and it is argued that the Court's continuing activism in relation to family rights is only in respect of Treaty rights, and that this has not been applied to the new Charter of Fundamental Rights. As such, the Court has failed to link Union citizenship and the Charter, which could have made for a more coherent sense of citizenship within the EU, but instead separates the application of fundamental rights from the unique concept of Union citizenship