Design and analysis of a gallium lanthanum sulfide based nanoplasmonic coupler yielding 67% efficiency

In this paper, we propose a novel ultra-compact nanoplasmonic coupler using gallium lanthanum sulfide (GLS) which yields an efficiency of 67% at the optical communication wavelength. The analysis has been done numerically using the finite-difference time-domain method. Our proposed coupler can operate at a broad frequency range and easier to fabricate than couplers with multi-section tappers since it is a simple rectangular-shaped coupler with no variation along the whole length.     

Effects of pnictogen and chalcogen bonds on the aromaticities of carbazole‐like and dibenzofuran‐like molecular skeletons: Cambridge Crystallographic Data Centre (CCDC) Study

Parameterization scheme used in geometry‐based aromaticity index Harmonic Oscillator Model for Heterocycles with π‐electrons and n‐electron delocalization was extended to cover certain pnictogen (group 15) and chalcogen (group 16) elements, for example, phosphorus, arsenic, selenium, and tellurium. Thus, assessment of aromaticities of dibenzofuran‐like and carbazole‐like molecular skeletons including the aforementioned pnictogens and chalcogens besides nitrogen, oxygen, and sulfur was made possible. Our results have shown that aromaticity of five‐membered and six‐membered rings in the considered skeletons can be independently treated from each other. Arsenic, phosphorus, and sulfur are the most suitable heteroatoms in the considered molecular skeletons to be used in designing π‐conjugated functional materials, because they have potentially smaller band gap due to the presence of the less aromatic flanking benzenes. Differences in aromaticities of two flanking benzenes of the molecular skeletons including pnictogens are more pronounced than those of molecular skeletons including chalcogens. Copyright © 2015 John Wiley & Sons, Ltd.     

Non-Newtonian ink transfer in gravure-offset printing

The inks used in gravure-offset printing are non-Newtonian fluids with higher viscosities and lower surface tensions than Newtonian fluids. This paper examines the transfer of a non-Newtonian ink between a flat plate and a groove when the plate is moved upward with a constant velocity while the groove is held fixed. Numerical simulations were carried out with the Carreau model to explore the behavior of this non-Newtonian ink in gravure-offset printing. The volume of fluid (VOF) method was implemented to capture the interface during the ink transfer process. The effects of varying the contact angle of the ink on the flat plate and groove walls and geometrical parameters such as the groove angle and the groove depth on the breakup time of the liquid filament that forms between the plate and the groove and the ink transfer ratio were determined. Our results indicate that increasing the groove contact angle and decreasing the flat plate contact angle enhance the ink transfer ratio and the breakup time. However, increasing the groove depth and the groove angle decreases the transfer ratio and the breakup time. By optimizing these parameters, it is possible to achieve an ink transfer from the groove to the flat plate of approximately 92%. Moreover, the initial width and the vertical velocity of the neck of the ink filament have significant influences on the ink transfer ratio and the breakup time.     

Formal Analysis of Optical Systems

Optical systems are becoming increasingly important by resolving many bottlenecks in today’s communication, electronics, and biomedical systems. However, given the continuous nature of optics, the inability to efficiently analyze optical system models using traditional paper-and-pencil and computer simulation approaches sets limits especially in safety-critical applications. In order to overcome these limitations, we propose to employ higher-order-logic theorem proving as a complement to computational and numerical approaches to improve optical model analysis in a comprehensive framework. The proposed framework allows formal analysis of optical systems at four abstraction levels, i.e., ray, wave, electromagnetic, and quantum.