Mathematical modeling of the magnetic properties of spheroids of hard second kind superconductors in the Bean model

Authors have modelled magnetic field in hard II-type superconductor bodies with cylindric symmetry by means of Bean model. Using the equations of electrodynamics and the Poisson equation for the vector potential, the Fredholm equation of the first kind is derived for the screening supercurrent density. By introducing the explicit form of the current-voltage characteristic and the law of electromagnetic induction, the equation for the supercurrent density is reduced to an integral equation of the 2nd kind, which is solved numerically in matrix form on a non-uniform grid with compaction to the edges of the sample. Density distribution of the screened superconductive current, sample-self magnetic field and hysteresis loops of magnetization in the cases of cylinders and spheroids are obtained.

A simple mung bean infection model for studying the virulence of Pseudomonas aeruginosa

Here we highlight the development of a simple and high throughput mung bean model to study virulence in the opportunistic pathogen Pseudomonas aeruginosa. The model is easy to setup and infection and virulence can be monitored for up to 10 days. In a first test of the model, we found that mung bean seedlings infected with PAO1 showed poor development of roots and high mortality rates compared to un-infected controls. We also found that a quorum sensing (QS) mutant was significantly less virulent when compared with the PAO1 wild type. Our work introduces a new tool for studying virulence in P. aeruginosa, that will allow for high throughput virulence studies of mutants, and for testing the in vivo efficacy of new therapies at a time when new antimicrobial drugs are desperately needed.

Microstructure and Superconductive Property of MgB2/Al Composite Materials

MgB2has the higher critical temperature of superconducting transition (TC: 39K) among the intermetallic compound superconductive materials, however, MgB2is hard for practical use because of its unworkable and lower critical current density (JC) in a high magnetic field than Nb-based superconductive materials. We have developed the original method of three-dimensional penetration casting (3DPC) to fabricate the MgB2/Al composite materials. In the composite material we made, MgB2particles dispersed to the matrix uniformly. Thus, these composite materials can be processed by machining, extrusion and rolling. TheTCwas determined by electrical resistivity and magnetization to be about 37～39K. In this work, we made composite material with ground MgB2particle with the purpose of extruding thinner wires of composite material, successfully produced φ1mm wire and changed the matrix from pure Al to Al-In alloy.JCof composite materials with the matrix of Al-In alloy was calculated from the width of the magnetic hysteresis based on the extended Bean model. The result was better than that of MgB2/Al composite material without Indium. Microstructures of these samples had been confirmed by SEM observation.

Microstructure and Superconductive Property of MgB2/Al Composite Materials

MgB2has the higher critical temperature of superconducting transition (TC: 39K) among the intermetallic compound superconductive materials, however, MgB2is hard for practical use because of its unworkable and lower critical current density (JC) in a high magnetic field than Nb-based superconductive materials. We have developed the original method of three-dimensional penetration casting (3DPC) to fabricate the MgB2/Al composite materials. In the composite material we made, MgB2particles dispersed to the matrix uniformly. Thus, these composite materials can be processed by machining, extrusion and rolling. TheTCwas determined by electrical resistivity and magnetization to be about 37～39K. In this work, we made composite material with ground MgB2particle with the purpose of extruding thinner wires of composite material, successfully produced φ1mm wire and changed the matrix from pure Al to Al-In alloy.JCof composite materials with the matrix of Al-In alloy was calculated from the width of the magnetic hysteresis based on the extended Bean model. The result was better than that of MgB2/Al composite material without Indium. Microstructures of these samples had been confirmed by SEM observation.