Assessment of the Exposure to Gradient Magnetic Fields Generated by MRI Tomographs: Measurement Method, Verification of Limits and Clearance Areas through a Web-Based Platform

This work is the result of a campaign of measures of exposure levels to magnetic field gradients (GMF) generated by magnetic resonance imaging (MRI) tomographs, to which both healthcare staff and any persons accompanying patients who remain inside the magnet room are exposed while performing a diagnostic Investigation. The study was conducted on three MRI tomographs with a static magnetic induction field up to 1.5 T installed in two hospitals of Lombardy. The study aims to characterize electromagnetic emissions within the magnet room and the definition of a measurement method suitable for assessing the level of exposure of healthcare personnel and any persons accompanying patients. The measurements performed concerned the determination of the weighted peak index for magnetic induction, due to the diagnostic GMF, relating to the action levels for the workers and the reference levels for the general population, in force in the European Union. Thanks to the defined experimental setup, the use of two different measuring instruments, and the software resources of the WEBNIR platform, it was possible to identify, for both categories of exposed persons, the “clearance” space, i.e., the distance from the magnet of the tomograph that guarantees health protection concerning the exposure to GMF, according to the indications of the standards in force. The method used showed that the exposure levels to GMF are substantially safe for professionally exposed workers who do not carry specific risks. For workers particularly sensitive to the specific risk, as well as to individuals part of the population, it is however advisable to maintain a distance from the magnet of about one meter to prevent sensorial neuromuscular stimulation effects.

An alternative approach for measuring yield stress and its application in Carbopol microgel

An innovative experimental apparatus for the direct measurement of yield stress was conceived and realized. It is based on a torsion pendulum equipped with a magnetic dipole and a rotating cylinder immersed in the material to be investigated. The pendulum equilibrium state depends on the mechanical torque applied due to an external magnetic induction field, elastic reaction of the suspension wire, and shear yield stress. Experimental results are reported showing that the behavior of the pendulum rotation angle, in different equilibrium conditions, provides evidence of the yield stress presence and enables its evaluation by equilibrium equations. The dependence on time of the equilibrium approach was also studied, contributing to shed light on the relaxation effect in the transition from a fluid-like to solid-like behavior, as well as on the eventual thixotropic effects in non-Newtonian fluids. The validity of the proposed technique and related experimental apparatus was tested in aqueous Carbopol solutions, with different weight percentages. The linear procedure, combined with the effectiveness and reliability of the proposed experimental method, candidates it to be used for the study of peculiar behaviors of other yield stress complex fluid such as blood, crude waxy oils, ice slurries, and coating layer used in the food industry and also for fault sliding in geodynamics.

An electron holography study of perpendicular magnetic tunnel junctions nanostructured by deposition on pre-patterned conducting pillars

Electron holography investigation of the magnetic induction field of perpendicular magnetic tunnel junctions for the fabrication of magnetic random access memories (MRAM), and temperature behavior.

THE EFFECT OF RUNNING IN AN ELECTROMAGNETIC FIELD ON HUMAN JOINT AND SKIN LUBRICATION IN THE METABOLIC PROCESS

This paper presents an experimental and theoretical implementation of the influence of the run-walk treatment in the presence of an electro-magnetic field on energy burn increments in the human body, its metabolism, and finally on the decrements of the human body weight. The experimental research presented in this paper was performed using the following devices: a magnetic induction field produced by a new Polish MT-24 Apparatus, a new German Magcell Arthro magneto electronic device, and a Segmental Body Composition Analyzer Tanita MC 780MA. The author's experience was gained in German research institutes, and practical results were confirmed after measurements and information from students and patients. Up to now, theoretical solutions have not been considered. The theoretical and numerical model presented was implemented by using the Mathcad 15 Professional Program. The main conclusion obtained in this paper can be formulated in the following sentence: The run-walk training implemented by an electro-magnetic magnetic field using tight sportswear leads to the increments of the dynamic viscosity of synovial fluid, changes the internal energy contained in the human body, increases the muscle weight, and the percentage of water in the human body; therefore, it accelerates the slimming process connected with the body weight decrements.

Magnetic Nernst effect

The thermodynamics of irreversible processes in continuous media predicts the existence of a magnetic Nernst effect that results from a magnetic analog to the Seebeck effect in a ferromagnet and magnetophoresis occurring in a paramagnetic electrode in contact with the ferromagnet. Thus, a voltage that has DC and AC components is expected across a Pt electrode as a response to the inhomogeneous magnetic induction field generated by magnetostatic waves of an adjacent YIG slab subject to a temperature gradient. The voltage frequency and dependence on the orientation of the applied magnetic induction field are quite distinct from that of spin pumping.

Magnetoelectric effect in a hydrogen molecule

The symmetry breaking due to a magnetic field applied on a hydrogen molecule H2 generates an electric polarization. This magnetoelectric effect occurs for electrons in a triplet state provided the magnetic induction field is not aligned with the symmetry axis of the molecule.