83 research outputs found

    Ultra-broadband Polarisers Based on Metastable Free-Standing Aligned Carbon Nanotube Membranes

    Get PDF
    A carbon nanotube free-standing linearly dichroic polariser is developed using solid-state extrusion. Membrane cohesion is experimentally and numerically demonstrated to derive from inter-tube van der Waals interactions in this family of planar metastable morphologies, controlled by the chemical vapour deposition conditions. Ultra-broadband polarisation (400 nm – 2.5 mm) is shown and corroborated by effective medium and full numerical simulations.This work was supported by the Isaac Newton Trust, Trinity College Cambridge University. M. T. Cole thanks the Winston Churchill Memorial Trust and the Oppenheimer Research Fellowship, Cambridge University, for generous financial support.This is the author accepted manuscript. The final version is available from Wiley at http://onlinelibrary.wiley.com/doi/10.1002/adom.201400238/abstract

    Normal parameter reduction algorithm in soft set based on hybrid binary particle swarm and biogeography optimizer

    Get PDF
    © 2019, Springer-Verlag London Ltd., part of Springer Nature. Existing classification techniques that are proposed previously for eliminating data inconsistency could not achieve an efficient parameter reduction in soft set theory, which effects on the obtained decisions. Meanwhile, the computational cost made during combination generation process of soft sets could cause machine infinite state, which is known as nondeterministic polynomial time. The contributions of this study are mainly focused on minimizing choices costs through adjusting the original classifications by decision partition order and enhancing the probability of searching domain space using a developed Markov chain model. Furthermore, this study introduces an efficient soft set reduction-based binary particle swarm optimized by biogeography-based optimizer (SSR-BPSO-BBO) algorithm that generates an accurate decision for optimal and sub-optimal choices. The results show that the decision partition order technique is performing better in parameter reduction up to 50%, while other algorithms could not obtain high reduction rates in some scenarios. In terms of accuracy, the proposed SSR-BPSO-BBO algorithm outperforms the other optimization algorithms in achieving high accuracy percentage of a given soft dataset. On the other hand, the proposed Markov chain model could significantly represent the robustness of our parameter reduction technique in obtaining the optimal decision and minimizing the search domain.Published versio

    Optical excitations of Skyrmions, knotted solitons, and defects in atoms

    Get PDF
    Analogies between non-trivial topologies of matter and light have inspired numerous studies, including defect formation in structured light and topological photonic band structures. Three-dimensional topological objects of localised particle-like nature attract broad interest across discipline boundaries from elementary particle physics and cosmology to condensed matter physics. Here we propose how simple structured light beams can be transformed into optical excitations of atoms with considerably more complex topologies representing three-dimensional particle-like Skyrmions. This construction can also be described in terms of linked Hopf maps, analogous to knotted solitons of the Skyrme-Faddeev model. We identify the transverse polarisation density current as the effective magnetic gauge potential for the Chern-Simons helicity term. While we prepare simpler two-dimensional baby-Skyrmions and singular defects using the traditional Stokes vectors on the Poincaré sphere for light, particle-like topologies can only be achieved in the full optical hypersphere description that no longer discards the variation of the total electromagnetic phase of vibration

    ADAPTIVE SEARCH MANAGER: An Engineering Design Decision Support Approach

    No full text
    INTRODUCTION Engineering design often involves several objectives. True engineering design solutions are not necessarily the global optimum as described by some mathematical simulation with respect to one criterion [Parmee and Denham (1)]. Often designer interaction is required to take into account many different criteria. In the case of multimodal design problems there may be quite different design solutions that perform similarly quantitatively, but have large differences in their degree of multi-criteria satisfaction. Criteria may include manufacturability, choice of materials, maintainability, reliability, specific customer requirement etc., many aspects of which can be qualitative in nature. Integrating all of these criteria into one comprehensive evaluation function is difficult and at times can be misleading. If the criteria are quantitative in nature a multiobjective genetic algorithm [Goldberg (2)] can be utilised. An attempt has been made at the Plymouth Engineerin
    corecore