Interpreting nucleation as a network formation process

In this paper we interpret nucleation as a network formation process. Inspired by this interpretation we propose a social network model which produces networks with communities.     

Modification of polystyrene maleic anhydride for efficient energy storage applications

Journal of Solid State Electrochemistry - The development of new energy storage devices has been gaining momentum in the wake of the energy crisis faced worldwide. New materials have been tried and...     

Segmented conjugated macromolecules containing silicon and boron: ADMET synthesis and luminescent properties

Boron‐ and silicon‐containing conjugated homo‐ and copolymers could be synthesized using acyclic diene metathesis (ADMET) condensation of bis‐styryl monomers. Both, tri‐and tetra‐coordinated boron monomers were successfully polymerized forming homopolymers, or random copolymers (if polymerized together with a silicon containing co‐monomer). Polymer molecular weights M_n were measured at ～6000 to 15,000 g/mol (NMR end group analysis) with molecular weight distributions M_w/M_n ～1.8 to 2.2. The polymers absorbed at λ_max ～317 to 406 nm and emitted at λ_max ～370 to 494 nm with fluorescent quantum efficiencies ～24 to 48%. The copolymer with tri‐coordinate boron showed highly efficient fluorescence quenching in the presence of fluoride ions at ratios boron/fluoride ～5/1, demonstrating its potential as anion sensor. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1707–1718     

Hierarchically porous organic polymers: highly enhanced gas uptake and transport through templated synthesis

Porous organic polymers (POPs) possessing meso- and micropores can be obtained by carrying out the polymerization inside a mesoporous silica aerogel template and then removing the template after polymerization. The total pore volume (tpv) and specific surface area (ssa) can be greatly enhanced by modifying the template (up to 210% increase for tpv and 73% for ssa) as well as by supercritical processing of the POPs (up to an additional 142% increase for tpv and an additional 32% for ssa) to include larger mesopores. The broad range of pores allows for faster transport of molecules through the hierarchically porous POPs, resulting in increased diffusion rates and faster gas uptake compared to POPs with only micropores.     

“Dial-In” Emission from a Unique Flexible Material with Polarization Tuneable Spectral Intensity

The development of organic photoluminescent materials, which show promising roles as catalysts, sensors, organic light-emitting diodes, logic gates, etc., is a major demand and challenge for the global scientific community. In this context, a photoclick polymerization method is adopted for the growth of a unique photoluminescent three-dimensional (3D) polymer film, E, as a model system that shows emission tunability over the range 350–650 nm against the excitation range 295–425 nm. The DFT analysis of energy calculations and π-stacking supports the spectroscopic observations for the material exhibiting a broad range of emission owing to newly formed chromophoric units within the film. Full polarization spectroscopic Mueller matrix studies were employed to extract and quantify the molecular orientational order of both the ground (excitation) and excited (emission) state anisotropies through a set of newly defined parameters, namely the fluorescence diattenuation and fluorescence polarizance. The information contained in the recorded fluorescence Mueller matrix of the organic polymer material provided a useful way to control the spectral intensity of emission by using pre- and post-selection of polarization states. The observation was based on the assumption that the longer lifetime of the excited dipolar orientation is attributed to the compactness of the film.     

AC Conduction and Time–Temperature Superposition Scaling in a Reduced Graphene Oxide–Zinc Sulfide Nanocomposite

We report, herein, the results of an in depth study and concomitant analysis of the AC conduction [σ′(ω): f=20 Hz to 2 MHz] mechanism in a reduced graphene oxide–zinc sulfide (RGO–ZnS) composite. The magnitude of the real part of the complex impedance decreases with increase in both frequency and temperature, whereas the imaginary part shows an asymptotic maximum that shifts to higher frequencies with increasing temperature. On the other hand, the conductivity isotherm reveals a frequency‐independent conductivity at lower frequencies subsequent to a dispersive conductivity at higher frequencies, which follows a power law [σ′(ω)∝ω^s] within a temperature range of 297 to 393 K. Temperature‐independent frequency exponent ′s′ indicates the occurrence of phonon‐assisted simple quantum tunnelling of electrons between the defects present in RGO. Finally, this sample follows the “time–temperature superposition principle”, as confirmed from the universal scaling of conductivity isotherms. These outcomes not only pave the way for increasing our elemental understanding of the transport mechanism in the RGO system, but will also motivate the investigation of the transport mechanism in other order–disorder systems.     

Singular Propositions,Negation and the Square of Opposition

This paper contains two traditions of diagrammatic studies namely one, the Euler–Venn–Peirce diagram and the other, following tradition of Aristotle, the square of oppositions. We put together both the traditions to study representations of singular propositions (through a diagram system Venn-i, involving constants), their negations and the inter relationship between the two. Along with classical negation we have incorporated negation of another kind viz. absence (taking a cue from the notion of ‘abhãva’ existing in ancient Indian knowledge system). We have also considered the changes that take place in the context of open universe.