A Miniaturized Flexible Surface Attachable Interrogator for Hybrid Optical Fiber Sensing

In this paper, we propose a miniaturized flexible interrogator for polarimetric and fiber Bragg grating (FBG) sensors based hybrid sensing scheme embedded in composite materials. The flexible interrogation module comprises of an Arrayed Waveguide (AWG) for FBG demodulation and an Electro Optic Mach- Zehnder Interferometric (EO-MZI) intensity modulator for polarimetric sensor demodulation. A customized design of AWG and EO- MZI are presented, and the designed performance resulted in a wide channel spacing of 5 nm and low cross talk of -34 dB between adjacent channels for the AWG, and a low Vπ voltage of ±1.5 Volt for the MZI-EO. The method for fabrication of the flexible interrogator device is also presented, based on post processing of platinum coated polyimide substrate. The film type interrogation module is compact, with a size of 3.4 cm x 0.1 cm x 0.01 cm. The surface attachable flexible hybrid sensor interrogator is proposed to integrate with photo detector arrays and wireless communication technology to enhance the competency of hybrid sensing scheme in smart sensing composite parts in motion for applications in aircraft, wind rotor blades, and so forth

Infiltration of a photonic crystal fiber with cholesteric liquid crystal and blue phase

Photonic crystal fibers (PCF) have been selectively filled with a cholesteric liquid crystal (ChLC) with special interest in the blue phase (BP) of the liquid crystal. It has been observed thermal tuning of the guided light in the visible region. A dramatically enhance appears when the phase of the liquid crystal changes from cholesteric to blue phase I (BPI). When a thermal range of the blue phase I is achieved, no changes are observed while increasing temperature from BPI through BPII and to the isotropic phase

The Participation of 3,3,3-Trichloro-1-nitroprop-1-ene in the [3+2] Cycloaddition Reaction with Selected Nitrile N-Oxides in the Light of the Experimental and MEDT Quantum Chemical Study

The regioselective zw-type [3 + 2] cycloaddition (32CA) reactions of a series of aryl-substituted nitrile N-oxides (NOs) with trichloronitropropene (TNP) have been both experimentally and theoretically studied within the Molecular Electron Density Theory (MEDT). Zwitterionic NOs behave as moderate nucleophiles while TNP acts as a very strong electrophile in these polar 32CA reactions of forward electron density flux, which present moderate activation Gibbs free energies of 22.8-25.6 kcal·mol−1 and an exergonic character of 28.4 kcal·mol−1 that makes them irreversible and kinetically controlled. The most favorable reaction is that involving the most nucleophilic MeO-substituted NO. Despite Parr functions correctly predicting the experimental regioselectivity with the most favorable O-CCCl3 interaction, these reactions follow a two-stage one-step mechanism in which formation of the O-C(CCl3) bond takes place once the C-C(NO2) bond is already formed. The present MEDT concludes that the reactivity differences in the series of NOs come from their different nucleophilic activation and polar character of the reactions, rather than any mechanistic feature

From Cyclo[18]carbon to the Novel Nanostructures—Theoretical Predictions

In this paper, we present a number of novel pure-carbon structures generated from cyclo[18]carbon. Due to the very high reactivity of cyclo[18]carbon, it is possible to link these molecules together to form bigger molecular systems. In our studies, we generated new structures containing 18, 36 and 72 carbon atoms. They are of different shapes including ribbons, sheets and tubes. All these new structures were obtained in virtual reactions driven by external forces. For every reaction, the energy requirement was evaluated exactly when the corresponding transition state was found or it was estimated through our new approach. A small HOMO–LUMO gap in these nanostructures indicates easy excitations and the multiple bonds network indicates their high reactivity. Both of these factors suggest that some potential applications of the new nanostructures are as components of therapeutically active carbon quantum dots, terminal fragments of graphene or carbon nanotubes obtained after fracture or growing in situ in catalytic reactions leading to the formation of carbonaceous materials