Gas discharge sustained by powerful THz and sub-THz gyrotrons in the mixtures of noble gases with nitrogen

The discharge propagation velocity towards electromagnetic radiation of sub-THz and THz bands was measured in various noble gases (argon, krypton) mixtures with nitrogen in the wide pressure range (0.1 – 2 atm) for various field intensities into the focal spot (from dozen of kW/cm2 to several MW/cm2). In the experimental setups two different gyrotrons were used. In case of 263 GHz it was CW gyrotron with power up 1 kW, in case of 670 GHz – pulsed gyrotron (20 μs) with power up to 40 kW. In both cases the focusing system provided the size of the focal spot of (2–3)·λ, which ensured the investigation of discharge phenomena in a wide pressure range (0.1 – 2 atm). In both cases discharge appeared in the focal spot spread towards heating radiation into the area with the field intensity much less than one in the focal spot. Velocity of the discharge propagation was measured by using photos from speed camera with small exposure (down to 20 ns) and streak camera. It was demonstrated that discharge velocity increase along with pressure decrease and drops with electric field decrease as it moves away from the focal spot.

Next-Gen Network: Microwave Perspective: Impact, Challenges and Opportunity

Our need for higher performance and improved efficiency has led to the invention of 4G from 1G. This tendency to never settle has now brought us to a new generation of mobile communication - 5G. It is expected to provide more than just a faster network. Reduced latency, enormous netwrok capacity, greater reliability and overall improved user experience. This has come into focus with the possibility that the unused spectrum - (300 MHz to 30 GHz) can also be brought into use in the telecommunication inductry. As we know, everything comes with its own demerits and in this review paper, we shall discuss the health effects that microwave radiation has on living organisms with the antennas and connected devices being in close proximity to users and other organisms. Thereafter, we shall discuss the challenges and opportunities of the same. Keywords: next generation network, millimeter waves, health impact, tissue heating, radiation

A study comparing Conventional Heating and Microwave Assistance Heating to Recover Metals from Municipal Solid Waste using Microwave-Assisted Leaching Technique

This study investigates and compares microwave-heating radiation with conventional heating. Incinerated municipal solid waste (IMSW) bottom ash (BA) and fly ash (FA) was utilized to recover various metals including Co, Cr, Cu, Fe, Mn, Zn,Pb, Al, Cd, Ba, Mg and V using various acid leaching agents i.e. HCl, HNO3 and H3PO4 were utilized and several parameters were altered in order to determine the most effective conditions. The current study concluded that microwave assisted leaching method is effective to recover most of the metals. In addtion, metals from MSWBA were much easier to recover in contrast with MSW-FA. 71% of Co, 75.69% of Cr, 56.19% of Cd, 35.23% of Ba and 30.2% of Pb, using 2M of HCl and 3M of H3PO4. While 1.48% of Cr, 0.93% of Fe, 1.19% of Mn, and 1.18% of Al were extracted using HCL and H3PO4 from MSWFA. It was also confirmed that higher power and longer contact time had a positive effect on metal recovery. From cost analysis point of view, microwave assisted leaching was fraction of the cost for conventional heating, making this method comparatively sustainable, energy efficient and safe.

Development of a correlation ECE radiometer for electron temperature fluctuation measurements in Heliotron J

A radial correlation ECE radiometer diagnostic has been developed for electron temperature fluctuation measurements in the helical-axis heliotron device, Heliotron J. The radiometer consists of two heterodyne detection systems. One system scans the frequency of a local oscillator from 52 to 64 GHz with a single intermediate frequency filter, and the second system has a fixed frequency, 56 GHz local oscillator with four intermediate frequency filters. This frequency range covers measurement positions spanning from the plasma core to the half radius. Laboratory tests indicate that each system has narrow intermediate frequency bandwidth and high-sensitivity over a large dynamic range. During plasma experiments with NBI heating, radiation temperature fluctuation measured by the CECE radiometer decrease with increasing ECCD commensurate with previous measurements of energetic particle driven modes on Heliotron J.

Investigation of Flammability, Thermal and Toxic Hazards of Liquid Materials in Vehicles

In case of vehicle fires, oil leakage fires along with the emissions of heat and smoke represent significant fire risk for the combustion of whole vehicles and ambient environment. In present study, the bench-scale cone calorimeter apparatus was employed to conduct fire hazards analysis. Three typical flammable oils, namely OAT, ATF and GLF were used as experimental materials. The heating radiation levels were set from 15 kW/m2 to 40 kW/m2 in steps of 5 kW/m2. Specific parameters, such as ignition time (TII), heat release rate (HRR), total heat release (THR) and CO concentration, have been studied to provide a comprehensive fire behavior assessment of the oils. The ignition times have a liner relationship with external heat fluxes. And the critical heat fluxes (CHF) of ATF and GLF are 6.0 kW/m2 and 3.8 kW/m2, respectively. The derived HRP, FPI and FGI values of ATF remarkably indicate that this oil can contribute more thermal hazard while OAT has the lowest. However, FED values reveal highest toxic hazards of GLF. OAT is the safest materials in terms of three typical oils.

N2O-Free single-pot conversion of cyclohexane to adipic acid catalysed by an iron(ii) scorpionate complex

Iron catalysed efficient single-pot adipic acid synthesis by cyclohexane oxidation with ozone in a solvent-, heating-, radiation- and N2O-free protocol.

Mixed convective MHD flow of a micropolar fluid with ohmic heating, radiation and viscous dissipation over a chemically reacting porous plate subjected to a constant heat flux and concentration gradient

In the present paper analysis of a chemically reacting mixed convection MHD micropolar flow, heat and mass transfer in porous medium with the effects of ohmic heating, radiation and viscous dissipation past an infinite vertical plate which is subjected to a constant heat flux and the concentration gradient. The non-linear coupled partial differential equations are solved numerically using an implicit finite difference scheme known as Keller-box method. The results for concentration, transverse velocity, angular velocity and temperature are obtained and illustrated graphically to observe the effects of various parameters, and the numerical discussion is presented with physical interpretations.