Simulation of air breakdown mechanism using different electrodes

Rapid growth in power sector of nation has given the opportunity to power engineers to protect the power equipment for reliable operation during their operating life. It has been seen from the several studies conducted by power engineers that one of the main problem in high voltage power (HV) equipment is the degradation of insulation i.e., quality of insulation of power equipment. As the high voltage power equipments are mainly subjected with spark over voltage causes by the lighting strokes, switching action, a protective device is used for determine the safe clearance required for proper insulation level. The sphere gaps are commonly used for measurements of peak values of high voltages and have been adopted by IEC and IEEE as a calibration device. Generally, the standard sphere gaps are widely used for protective device in electrical power equipments. The sphere gaps are filled up with insulating medium such as liquid insulation (transformer oil), and gas insulation (SF6, N2, CO2, CCl2F2 etc.) in HV power equipments. Normally, air medium is widely used as an insulating medium in different electrical power equipments as its breakdown strength is 30kV/cm. Therefore electrical breakdown characteristic of small air gap under the different applied voltage has its great significance for the design consideration of various air insulated HV equipment. In addition, the effect of breakdown voltage on different insulation like lamiflex, leatheroid, plywood, craft paper, and polyester fiber has also been studied. To observe the effect on insulation due to breakdown mechanism, the insulation samples are collected both before and after breakdown voltage test and analysis has been done with the help of Scanning electron microscope (SEM). To simulate the air breakdown voltage with and without the insulation barrier has been studied experimentally in high voltage laboratory, a standard diameter of 25 cm spheres are used for measurement of air breakdown voltages and electric field of the high voltage equipments. The above experiment is conducted at the normal temperature and pressure. The simulation of such air breakdown voltage has been carried out in the COMSOL environment. Finally, the experimental result has been compared with theoretical, and simulation results.

Magnetic Order Beyond RKKY in the Classical Kondo Lattice

We study the Kondo lattice model of band electrons coupled to classical spins, in three dimensions, using a combination of variational calculation and Monte Carlo. We use the weak coupling `RKKY' window and the strong coupling regime as benchmarks, but focus on the physically relevant intermediate coupling regime. Even for modest electron-spin coupling the phase boundaries move away from the RKKY results, the non interacting Fermi surface no longer dictates magnetic order, and weak coupling `spiral' phases give way to collinear order. We use these results to revisit the classic problem of 4f magnetism and demonstrate how both electronic structure and coupling effects beyond RKKY control the magnetism in these materials.Comment: 6 pages, 4 figs. Improved figures, expanded captions. To appear in Europhys. Let

In-Situ absolute phase detection of a microwave field via incoherent fluorescence

Measuring the amplitude and the absolute phase of a monochromatic microwave field at a specific point of space and time has many potential applications, including precise qubit rotations and wavelength quantum teleportation. Here we show how such a measurement can indeed be made using resonant atomic probes, via detection of incoherent fluorescence induced by a laser beam. This measurement is possible due to self-interference effects between the positive and negative frequency components of the field. In effect, the small cluster of atoms here act as a highly localized pick-up coil, and the fluorescence channel acts as a transmission line.Comment: 13 pages, 5 figure

Queue Length and Server Content Distribution in an Infinite-Buffer Batch-Service Queue with Batch-Size-Dependent Service

We analyze an infinite-buffer batch-size-dependent batch-service queue with Poisson arrival and arbitrarily distributed service time. Using supplementary variable technique, we derive a bivariate probability generating function from which the joint distribution of queue and server content at departure epoch of a batch is extracted and presented in terms of roots of the characteristic equation. We also obtain the joint distribution of queue and server content at arbitrary epoch. Finally, the utility of analytical results is demonstrated by the inclusion of some numerical examples which also includes the investigation of multiple zeros

Building digital entrepreneurial platform through local community activity and digital skills in aboriginal Australia

© 2018 Pradhan, Beetson & Kutay. This research is situated in the Ngemba community which includes the township known as Brewarrina. It is located approximately 900 kms north west of Sydney and classified ‘Very Remote Australia’. Brewarrina’s recorded Aboriginal population in 2016 was 71.09% contrasted with the total Indigenous Australian population being 2.8%. The Australian Government have identified Brewarrina in the ‘Digital Divide’ category. Closing the gap on socio-economic disadvantage and the digital divide is directly related to economic development and national priorities include Aboriginal peoples’ employment as an identified target under the banner of the 'Close the Gap' initiative. The Australian government stated the national broadband network (NBN) initiative and ICTs would assist in achieving such priorities. Despite such strategies and initiatives, direct action has yet to be realised. This raises opportunities for targeted networking interactions within and beyond community, offering innovative approaches to countering these priorities. This research will implement and verify an innovative model that facilitates community digital entrepreneurship. The model proposes several practical applications, including community members' ability to promote community entrepreneurship and community members’ skills development