Physics, electrochemistry, chemistry, and electronics of the vanadium redox flow battery by analyzing all the governing equations.

The vanadium redox flow battery has been intensively examined since the 1970s, with researchers looking at its electrochemical time varying electrolyte concentration time variation equations (both tank and cells, for negative and positive half cells), its thermal time variation equations, and fluid flow equations. Chemistry behavior of the electrolyte ions have also been intensively examined too. In this perspective, all of the phenomena have been examined, unified and presented together with their physical chemistry shown in the appropriate equations. This is done by providing the field equations for the battery, which are electronic, electrochemical, chemical, physics of fluid dynamics, and thermal physics of heat transport, in character. They are interpreted in new analytical equations providing fundamental scientific insights, as well as allowing engineering and manufacturing assessments. Graphs of pressure trend in electrodes, power and temperature tables for electrode and current collector loss mechanisms are provided. Current density, concentration, electrostatic, and overpotential functional dependences in the electrodes are given.

First principles quantum calculations for graphyne for electronic devices.

Moving beyond traditional 2D materials is now desirable in order to have switching capabilities (e.g., transistors). Here we propose using γ graphyne-n because, as shown in this paper, obtaining regions of the electronic band structure which act as valence and conduction bands, with an apparent bandgap, are found. Electron spatial density and electronic band structures with ε(k) vs. k are calculated for graphyne-1 and graphyne-2 having respectively, one and two triple C-C carbon-carbon bonds between adjoining benzene rings; such side by side comparisons never before done. The ab initio quantum calculations were performed using both the local density approximation (LDA) and the generalized gradient approximation (GGA) for density functional theory (DFT).

Negative-refractive bicrystal with broken symmetry produces asymmetric electromagnetic fields in guided-wave heterostructures.

Heterostructure arrangements of uniaxial bicrystals have been discovered to produce electromagnetic fields with asymmetric distributions in guide wave structures. The property behind this remarkable phenomenon is the broken crystalline symmetry which allows the new physics to be seen in unsymmetric distributions. Here the theory behind this phenomenon is presented, numerical calculations are performed using an ab initio anisotropic Green's function approach, and the results provided at 10 GHz for a realistic crystal system with nominal permittivity of 5. Asymmetric distributions seen here are one facet of the broken symmetry property which generates negative refraction for impinging waves on a bicrystal.

Physics of propagation in left-handed guided wave structures at microwave and millimeter-wave frequencies.

A microstrip configuration is loaded with a left-handed medium substrate and studied regarding its dispersion diagrams over the microwave and millimeter-wave frequency bands for a number of different modal solutions. Ab initio calculations are accomplished self-consistently with a computer code using a full-wave integral equation numerical method based upon a Green's function employing appropriate boundary conditions. Bands of both propagating and evanescent behavior are discovered in some of the modes. Electromagnetic field plots in the cross-sectional dimension are made. New electric field line and magnetic circulation patterns are discovered.