Emerging Powers and Global Order: Much Ado About Nothing?

This is the final version of the paper. Available from University of Hamburg via the link in this record.Part of the PRIMO Working Paper Series.This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 607133

Towards efficient modelling of optical micromanipulation of complex structures

Computational methods for electromagnetic and light scattering can be used for the calculation of optical forces and torques. Since typical particles that are optically trapped or manipulated are on the order of the wavelength in size, approximate methods such as geometric optics or Rayleigh scattering are inapplicable, and solution or either the Maxwell equations or the vector Helmholtz equation must be resorted to. Traditionally, such solutions were only feasible for the simplest geometries; modern computational power enable the rapid solution of more general--but still simple--geometries such as axisymmetric, homogeneous, and isotropic scatterers. However, optically-driven micromachines necessarily require more complex geometries, and their computational modelling thus remains in the realm of challenging computational problems. We review our progress towards efficient computational modelling of optical tweezers and micromanipulation, including the trapping and manipulation of complex structures such as optical micromachines. In particular, we consider the exploitation of symmetry in the modelling of such devices.Comment: 5 pages, 4 figure

Modelling optical micro-machines

A strongly focused laser beam can be used to trap, manipulate and exert torque on a microparticle. The torque is the result of transfer of angular momentum by scattering of the laser beam. The laser could be used to drive a rotor, impeller, cog wheel or some other microdevice of a few microns in size, perhaps fabricated from a birefringent material. We review our methods of computationally simulating the torque and force imparted by a laser beam. We introduce a method of hybridizing the T-matrix with the Finite Difference Frequency Domain (FDFD) method to allow the modelling of materials that are anisotropic and inhomogeneous, and structures that have complex shapes. The high degree of symmetry of a microrotor, such as discrete or continuous rotational symmetry, can be exploited to reduce computational time and memory requirements by orders of magnitude. This is achieved by performing calculations for only a given segment or plane that is repeated across the whole structure. This can be demonstrated by modelling the optical trapping and rotation of a cube.Comment: 4 pages, 3 figure

Financial Capability and Asset Building in the Curricula: Student Perceptions

Although social work education competencies include economic justice, and practice includes addressing client finances and assets, social work curricula lack an emphasis on these topics. Little is known about students’ perceptions of the relevancy of this information or how well their program is preparing them for contemporary practice. This study explores the perceptions of 643 BSW and MSW students and finds a general consensus that social workers have an important role in addressing client economic issues. However, respondents perceive limited use of client financial information in practice and limited coverage of the topic in curriculum areas. Results indicate respondents’ perceptions may significantly differ based on their preferred fields of practice, level, and student program status. Curricula implications are discusse