Taylor-Green vortex simulation using CABARET scheme in a weakly compressible formulation

In present paper we recall the canonical Taylor-Green vortex problem solved by in-house implementation of the novel CABARET numerical scheme in weakly compressible formulation. The simulations were carried out on the sequence of refined grids with $64^3$, $128^3$, $256^3$ cells at various Reynolds numbers corresponding to both laminar (${\rm Re}=100, 280$) and turbulent (${\rm Re}=1600, 4000$) vortex decay scenarios. The features of the numerical method are discussed in terms of the kinetic energy dissipation rate and integral enstrophy curves, temporal evolution of the spanwise vorticity, energy spectra and spatial correlation functions

Unexpected Room Temperature Ferromagnetism of a Ball-Milled Graphene Oxide—Melamine Mixture

Nitrogen-doped carbon nanomaterial (NDCNM) was synthesized by grinding a mixture of graphene oxide and melamine in a planetary mill with both balls and milling chamber of zirconium dioxide. In the electron spin resonance spectrum of NDCNM, a broad signal with g = 2.08 was observed in addition to a narrow signal at g = 2.0034. In the study using a vibrating-sample magnetometer, the synthesized material is presumably a ferromagnet with a coercive force of 100 Oe. The specific magnetization at 10,000 Oe is approximately 0.020 and 0.055 emu/g at room temperature and liquid nitrogen temperature, respectively

A Facile Synthesis of Noble-Metal-Free Catalyst Based on Nitrogen Doped Graphene Oxide for Oxygen Reduction Reaction

A simple method for the mechanochemical synthesis of an effective metal-free electrocatalyst for the oxygen reduction reaction was demonstrated. A nitrogen-doped carbon material was obtained by grinding a mixture of graphene oxide and melamine in a planetary ball mill. The resulting material was characterized by XPS, EPR, and Raman and IR spectroscopy. The nitrogen concentration on the N-bmGO surface was 5.5 at.%. The nitrogen-enriched graphene material (NbmGO has half-wave potential of −0.175/−0.09 V and was shown to possess high activity as an electrocatalyst for oxygen reduction reaction. The electrocatalytic activity of NbmGO can be associated with a high concentration of active sites for the adsorption of oxygen molecules on its surface. The high current retention (93% for 12 h) after continuous polarization demonstrates the excellent long-term stability of NbmGO

Taylor-Green vortex simulation using CABARET scheme in a weakly compressible formulation

In present paper we recall the canonical Taylor-Green vortex problem solved by in-house implementation of the novel CABARET numerical scheme in weakly compressible formulation. The simulations were carried out on the sequence of refined grids with $64^3$, $128^3$, $256^3$ cells at various Reynolds numbers corresponding to both laminar (${\rm Re}=100, 280$) and turbulent (${\rm Re}=1600, 4000$) vortex decay scenarios. The features of the numerical method are discussed in terms of the kinetic energy dissipation rate and integral enstrophy curves, temporal evolution of the spanwise vorticity, energy spectra and spatial correlation functions

Storage Ring to Search for Electric Dipole Moments of Charged Particles -- Feasibility Study

The proposed method exploits charged particles confined as a storage ring beam (proton, deuteron, possibly helium-3) to search for an intrinsic electric dipole moment (EDM) aligned along the particle spin axis. Statistical sensitivities could approach 10$^{-29}$ e$\cdot$cm. The challenge will be to reduce systematic errors to similar levels. The ring will be adjusted to preserve the spin polarisation, initially parallel to the particle velocity, for times in excess of 15 minutes. Large radial electric fields, acting through the EDM, will rotate the polarisation. The slow rise in the vertical polarisation component, detected through scattering from a target, signals the EDM. The project strategy is outlined. It foresees a step-wise plan, starting with ongoing COSY (Cooler Synchrotron, Forschungszentrum J\'ulich) activities that demonstrate technical feasibility. Achievements to date include reduced polarisation measurement errors, long horizontal-plane polarisation lifetimes, and control of the polarisation direction through feedback from the scattering measurements. The project continues with a proof-of-capability measurement (precursor experiment; first direct deuteron EDM measurement), an intermediate prototype ring (proof-of-principle; demonstrator for key technologies), and finally the high precision electric-field storage ring