All-optical transport and compression of ytterbium atoms into the surface of a solid immersion lens

We present an all-optical method to load 174Yb atoms into a single layer of an optical trap near the surface of a solid immersion lens which improves the numerical aperture of a microscope system. Atoms are transported to a region 20 um below the surface using a system comprised by three optical dipole traps. The "optical accordion" technique is used to create a condensate and compress the atoms to a width of 120 nm and a distance of 1.8 um away from the surface. Moreover, we are able to verify that after compression the condensate behaves as a two-dimensional quantum gas.Comment: 5 pages, 5 figure

Two-Dimensional Fluctuating Vesicles in Linear Shear Flow

The stochastic motion of a two-dimensional vesicle in linear shear flow is studied at finite temperature. In the limit of small deformations from a circle, Langevin-type equations of motion are derived, which are highly nonlinear due to the constraint of constant perimeter length. These equations are solved in the low temperature limit and using a mean field approach, in which the length constraint is satisfied only on average. The constraint imposes non-trivial correlations between the lowest deformation modes at low temperature. We also simulate a vesicle in a hydrodynamic solvent by using the multi-particle collision dynamics technique, both in the quasi-circular regime and for larger deformations, and compare the stationary deformation correlation functions and the time autocorrelation functions with theoretical predictions. Good agreement between theory and simulations is obtained.Comment: 13 pages, 7 figure

Feasibility of Application of Modern Methods of Construction in Iran

Various plans and policies have been adopted by the Iranian Government to address the housing shortages in Iran. Some of these policies have been successful and some have failed dramatically deteriorating the housing conditions. Technology transfer from other countries, such as the UK, may facilitate industrialisation which has been recognised as an effective way to address housing deficiencies in Iran. The Iranian and UK construction industries, however, differ in various respects which may increase the risk of failure if transferred technologies are not adapted to Iranian needs and conditions. This paper compares the current conditions of the Iranian and UK construction industries to identify the risks and opportunities if Modern Methods of Construction (MMC) were to be transferred from the UK to Iran. Several issues such as demand and supply, regulations and standards, practicality, costs, design, sustainability, and governmental policies have been studied in detail. The results reveal that MMC could potentially improve the housing conditions in Iran by addressing major issues such as skilled labour shortages, energy and materials wastes, building quality and speed of construction. The major risks are also identified as volatile economy and housing market, transportation and industry capacity. The chance of successful adoption is considerably higher for those MMC that are suitable for small projects, do not require highly skilled labour and heavy machinery, and are compatible with prevailing methods of construction in Iran

Solvent-free coarse-grained lipid model for large-scale simulations

A coarse-grained molecular model, which consists of a spherical particle and an orientation vector, is proposed to simulate lipid membrane on a large length scale. The solvent is implicitly represented by an effective attractive interaction between particles. A bilayer structure is formed by orientation-dependent (tilt and bending) potentials. In this model, the membrane properties (bending rigidity, line tension of membrane edge, area compression modulus, lateral diffusion coefficient, and flip-flop rate) can be varied over broad ranges. The stability of the bilayer membrane is investigated via droplet-vesicle transition. The rupture of the bilayer and worm-like micelle formation can be induced by an increase in the spontaneous curvature of the monolayer membrane.Comment: 13 pages, 19 figure