Simulation Of Microtearing Turbulence In NSTX

Thermal energy confinement times in NSTX dimensionless parameter scans increase with decreasing collisionality. While ion thermal transport is neoclassical, the source of anomalous electron thermal transport in these discharges remains unclear, leading to considerable uncertainty when extrapolating to future ST devices at much lower collisionality. Linear gyrokinetic simulations find microtearing modes to be unstable in high collisionality discharges. First non-linear gyrokinetic simulations of microtearing turbulence in NSTX show they can yield experimental levels of transport. Magnetic flutter is responsible for almost all the transport ({approx}98%), perturbed field line trajectories are globally stochastic, and a test particle stochastic transport model agrees to within 25% of the simulated transport. Most significantly, microtearing transport is predicted to increase with electron collisionality, consistent with the observed NSTX confinement scaling. While this suggests microtearing modes may be the source of electron thermal transport, the predictions are also very sensitive to electron temperature gradient, indicating the scaling of the instability threshold is important. In addition, microtearing turbulence is susceptible to suppression via sheared E-B flows as experimental values of E-B shear (comparable to the linear growth rates) dramatically reduce the transport below experimental values. Refinements in numerical resolution and physics model assumptions are expected to minimize the apparent discrepancy. In cases where the predicted transport is strong, calculations suggest that a proposed polarimetry diagnostic may be sensitive to the magnetic perturbations associated with the unique structure of microtearing turbulence

Synthesis and characterization of Sn‑doped TiO2 flm for antibacterial applications

Simple sol–gel method has been exploited to deposit Sn-doped TiO2 thin flms on glass substrates. The resultant coatings were characterized by X-ray difraction (XRD), UV–visible techniques (UV–Vis), Fourier transform infrared spectroscopy (FTIR), and photoluminescence analysis (PL). The XRD pattern reveals an increase in crystallite size of the prepared samples with the increasing doping concentration. A decrease in doping concentrating resulted in the decrease in bandgap values. The diferent chemical bonds on these flms were identifed from their FTIR spectra. The photoluminescence analysis shows an increase in the emission peak intensity with increasing dopant concentration, and this can be attributed to the efect created due to surface states. The prepared samples were tested as antibacterial agent toward both Gram-positive and Gram-negative bacteria like S.aureus (Staphylococcus aureus) and E.coli (Escherichia coli), respectively. The size of the inhibition zones indicates that the sample shows maximum inhibitory property toward E.coli when compared to S.aureus

Influence of the calcination of TiO2-reduced graphite hybrid for the photocatalytic reduction of carbon dioxide

In this work, a conversion of carbon dioxide (CO2) into methane, carbon monoxide, as well as hydrogen was investigated. The TiO2/rGO photocatalysts were prepared by two steps: solvothermal method and calcination at 500, 800, and 1000 degrees C in an argon atmosphere. The obtained samples were characterized by X-ray diffraction (XRD), UV-vis diffuse reflection spectroscopy (UV-vis/DRS), N2 adsorption-desorption and analysis of carbon content. The activity of photocatalysts was evaluated in the photocatalytic reduction of CO2. The TiO2/rGO-10 without calcination showed the highest activity toward CO2 conversion. It was found that all samples after rGO modification exhibited good activity toward H2 generation with high selectivity. The enhanced photocatalytic performance was attributed mainly to the presence of graphene due to its excellent electron transport/collection ability.Web of Science380403