Inductive measurements of third-harmonic voltage and critical current density in bulk superconductors

We propose an inductive method to measure critical current density $J_c$ in bulk superconductors. In this method, an ac magnetic field is generated by a drive current $I_0$ flowing in a small coil mounted just above the flat surface of superconductors, and the third-harmonic voltage $V_3$ induced in the coil is detected. We present theoretical calculation based on the critical state model for the ac response of bulk superconductors, and we show that the third-harmonic voltage detected in the inductive measurements is expressed as $V_3= G_3\omega I_0^2/J_c$, where $\omega/2\pi$ is the frequency of the drive current, and $G_3$ is a factor determined by the configuration of the coil. We measured the $I_0$-$V_3$ curves of a melt-textured $\rm YBa_2Cu_3O_{7-\delta}$ bulk sample, and evaluated the $J_c$ by using the theoretical results.Comment: 3 pages, 1 figure, submitted to Appl. Phys. Let

Carrier Relaxation Dynamics in the Organic Superconductor kappa-(BEDT-TTF)(2)Cu(NCS)(2) Under Pressure

Photo-induced carrier relaxation dynamics have been investigated for the organic superconductor kappa-(BEDT-TTF)(2)Cu(NCS)(2) with different probe polarization under 1.3 kbar at low temperatures. We successfully observed the isotropic and anisotropic responses for the probe polarization, which were found to appear at 56 K. By comparing the responses with and without applying pressure, we found that those were slightly changed, indicating that the application of pressure has effect on the carrier relaxation dynamics

An Experimental Study on Bed Degradation Due to Falling Works Improvement

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Observations and Modeling of Rainfall and Sediment Runoff in the Lesti River Basin, Tributary of the Brantas River, Indonesia

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Initial Condition Dependene of Dynamis and Evaporation of Polymer Spallation Partiles Flying in Polymer Ablated Arcs

This paper describes the influence of initial conditions for spallation particles flying in polymer ablation arcs on dynamics and evaporation of the polymer spallation particles using the numerical model. Through our previous experiments, we had found micro-sized `spallation particles\u27 ejected from polyamide materials by thermal plasma contact. To obtain the dynamics of spallation particles in polymer ablation arcs, we have developed a numerical model on dynamics of spallation particles flying in the polymer ablated arcs. The influence of pressure inside the polymer ablated arc, the initial particle diameter and the initial velocity of spallation particles were studied as parameters in the present paper. Under the given temperature and gas flow distributions in specified initial conditions, the trajectories of spallation particles flying in the polymer ablated arc were simulated numerically, considering the time variations in the temperature and the diameter of the particles. The results show that the highest flight altitude of the PA6 spallation particle flying in the PA6 ablated arc is affected by the initial particle diameter and velocity remarkably

Spallation occurrence from polyamide materials irradiated by thermal plasma with water absorption

This paper first describes the effect of water absorption in polyamide material irradiated by thermal plasmas on the occurrence of spallation phenomena. The interaction between polyamide materials and arc plasmas occurs particularly in the low voltage circuit breaker and aerospace fields. Spallation phenomena are those in which polymer particles are ejected from polymer bulk materials irradiated by high heat flux. To confirm the effect of water absorption into the polyamide material on spallation phenomena, polyamide specimens with and without water absorption were irradiated by Ar inductively coupled thermal plasma. The results show that the polyamide specimen with water absorption ejected spallation particles, whereas the polyamide specimen without water absorption were only slightly ejected, indicating that water absorption promotes the occurrence of spallation. The cooling effects of the spallation polyamide 66 (PA66) particles ablation were also estimated in hot air to assess the arc quenching ability from the spallation particle inclusion. This estimation showed that 10 and more PA66 particles inclusion might decrease the air temperature by 3000 K effectively, which can be useful to enhance arc quenching in circuit breakers working in air. © 2016 IOP Publishing Ltd.Embargo Period 12 month