Effect Of Transient Field Research Articles

Experiment of dynamic property and transient magnetic effects of coal during deformation and fracture

Combining separated SHPB test device of ϕ50 mm with ZDKT-type 1 transient magnetic resonance test system, long drop bar of 400 mm was used to impact coal specimens at four different speeds: 1.275, 3.287, 6.251, and 7.404 m/s. The change in waveform, the dynamic mechanical properties, and the generated effect of transient field during the coal deformation and fracture under the loads were discussed and analyzed. While magnetic signals during the coal fracture firstly needed EEMD, decomposition then had a FFT with Data Demon. The main results of the experiment are the following: the main frequency of magnetic signals was between 220 and 450 kHz and the instantaneous frequency during the damage of coal would have the instantaneous jump.

Estimation of Transient over Voltages in Gas Insulated Busduct from 220kv Gas Insulated Substation

The transient over voltages are generated in gas insulated substations (GIS) during switching operation of substations in the order of a few nanoseconds. These transients have traveling wave behavior and travel to external systems through discontinuities and interface such as enclosures, bushings, cable joints etc. Depending up on configuration of the GIS and the amplitude of the electric and magnetic fields could be of the order of a few tens of kilovolts per meter and a few hundreds of amps per meter respectively. These very fast transient over (VFTO) voltages create critical situations in protection circuit and control circuit and makes raise faults in cables, transformers and secondary circuits, which result in malfunctioning of the primary equipment. The suppression of VFTO is very important in GIS systems. In this paper, included estimation of transient voltages in the switching operations has been calculated due to transient field with respect to 220kv gas insulated substation during switching operation. The effect of Transient field have been analyzed and clearly demonstrated for substation by develop of suitable simulation model to estimate over transient voltages. The proposed approach successfully implemented in the platform of MATLAB software.

Transient field-effect and time-of-flight investigation of chalcogenide glasses

We have studied hole transport in amorphous As2Te3 (a-As2Te3) films by time-of-flight (TOF) and transient field-effect (TFE) measurements. Since the mobility gap of this material is small, the TOF experiments could be carried out only at temperatures below 200 K. Transport appears to be dispersive, due to multiple trapping in the valence-band tail. In order to extend the observations to higher temperature and longer times, we have developed a new technique, the TFE. A careful analysis shows that TFE data can be dispersive even if transport is nondispersive, because a long thin-film transistor is equivalent to a transmission line. Nevertheless, the resulting data can be used to characterize the density of states beyond the mobility edge. We find that multiple trapping indeed predominates, and the valence-band tail is exponential with a characteristic temperature of about 290 K. This is somewhat lower than indicated by TOF data, probably because hopping transport predominates at low temperatures. The long-time transients can be associated with either neutral defect interconversion and a continuous distribution of decay times or deep traps near the semiconductor-oxide interface. However, the ultimate disappearance of the response reflects the effects of Fermi-level pinning by valence alternation pairs with a negative effective correlation energy, as expected.

Implantation perturbed angular correlation experiments in iron after inelastic proton scattering

Hyperfine interactions in iron metal have been studied by the standard IMPACT technique, populating the 0.847 MeV, 10.4 ps state of 56 Fe and the 1.408 MeV, 1.42 ps state of 54 Fe via the ( p, p' ) nuclear reaction. Several experiments on 56 Fe were performed independently at the University of Wisconsin Tandem Van de Graaff accelerator laboratory and at the Rutgers-Bell facility. In all cases, the experiments yielded shifts of less than 0.005 rad in the correlation pattern. The low results imply that the average hyperfine field in iron implanted into iron is less than 175 kG during the first 10 ps after implantation. The results are discussed in terms of possible radiation damage and transient field effects, and microscopic details of the IMPACT process are considered.