Hierarchical Assemblies of Superparamagnetic Colloids in Time-Varying Magnetic Fields

Soft Matter ◽  
2021 ◽  
Author(s):  
Aldo Spatafora-Salazar ◽  
Dana Lobmeyer ◽  
Lucas Hildebrand Pires da Cunha ◽  
Kedar Joshi ◽  
Sibani Lisa Biswal
Keyword(s):  
Magnetic Fields ◽  
Time Varying ◽  
Dipolar Interactions ◽  
Colloidal Assembly ◽  
Particle Assemblies

Magnetically-guided colloidal assembly has proven to be a versatile method for building hierarchical particle assemblies. This review describes the dipolar interactions that govern superparamagnetic colloids in time-varying magnetic fields, and...

scholarly journals Millimeter (MM) wave and microwave frequency radiation produce deeply penetrating effects: the biology and the physics

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Martin L. Pall
Keyword(s):  
Magnetic Fields ◽  
Electric Fields ◽  
Cardiac Activity ◽  
Maximum Level ◽  
Voltage Sensor ◽  
The Body ◽  
Time Varying ◽  
The Brain ◽  
Mm Waves

Abstract Millimeter wave (MM-wave) electromagnetic fields (EMFs) are predicted to not produce penetrating effects in the body. The electric but not magnetic part of MM-EMFs are almost completely absorbed within the outer 1 mm of the body. Rodents are reported to have penetrating MM-wave impacts on the brain, the myocardium, liver, kidney and bone marrow. MM-waves produce electromagnetic sensitivity-like changes in rodent, frog and skate tissues. In humans, MM-waves have penetrating effects including impacts on the brain, producing EEG changes and other neurological/neuropsychiatric changes, increases in apparent electromagnetic hypersensitivity and produce changes on ulcers and cardiac activity. This review focuses on several issues required to understand penetrating effects of MM-waves and microwaves: 1. Electronically generated EMFs are coherent, producing much higher electrical and magnetic forces then do natural incoherent EMFs. 2. The fixed relationship between electrical and magnetic fields found in EMFs in a vacuum or highly permeable medium such as air, predicted by Maxwell’s equations, breaks down in other materials. Specifically, MM-wave electrical fields are almost completely absorbed in the outer 1 mm of the body due to the high dielectric constant of biological aqueous phases. However, the magnetic fields are very highly penetrating. 3. Time-varying magnetic fields have central roles in producing highly penetrating effects. The primary mechanism of EMF action is voltage-gated calcium channel (VGCC) activation with the EMFs acting via their forces on the voltage sensor, rather than by depolarization of the plasma membrane. Two distinct mechanisms, an indirect and a direct mechanism, are consistent with and predicted by the physics, to explain penetrating MM-wave VGCC activation via the voltage sensor. Time-varying coherent magnetic fields, as predicted by the Maxwell–Faraday version of Faraday’s law of induction, can put forces on ions dissolved in aqueous phases deep within the body, regenerating coherent electric fields which activate the VGCC voltage sensor. In addition, time-varying magnetic fields can directly put forces on the 20 charges in the VGCC voltage sensor. There are three very important findings here which are rarely recognized in the EMF scientific literature: coherence of electronically generated EMFs; the key role of time-varying magnetic fields in generating highly penetrating effects; the key role of both modulating and pure EMF pulses in greatly increasing very short term high level time-variation of magnetic and electric fields. It is probable that genuine safety guidelines must keep nanosecond timescale-variation of coherent electric and magnetic fields below some maximum level in order to produce genuine safety. These findings have important implications with regard to 5G radiation.

Magnetoelastic Waves in Time‐Varying Magnetic Fields. I. Theory

1969 ◽  
Vol 40 (2) ◽  
pp. 524-536 ◽  
Author(s):  
S. M. Rezende ◽  
F. R. Morgenthaler
Keyword(s):  
Magnetic Fields ◽  
Time Varying ◽  
Magnetoelastic Waves

scholarly journals Crustal and time-varying magnetic fields at the InSight landing site on Mars

2020 ◽  
Vol 13 (3) ◽  
pp. 199-204 ◽  
Author(s):  
Catherine L. Johnson ◽  
Anna Mittelholz ◽  
Benoit Langlais ◽  
Christopher T. Russell ◽  
Véronique Ansan ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Landing Site ◽  
Time Varying

scholarly journals EM Site A.C. Magnetic Field Sources, Surveys and Solutions Part IV: Survey Data Analysis

1996 ◽  
Vol 4 (4) ◽  
pp. 20-21
Author(s):  
Curt Dunnam
Keyword(s):  
Magnetic Field ◽  
Data Analysis ◽  
Magnetic Fields ◽  
Survey Data ◽  
Field Survey ◽  
Survey Methods ◽  
Time Varying ◽  
Measured Field ◽  
The Magnetic Field ◽  
Analyze Data

Up to the present waypoint in this series on EM site magnetic fields, we have identified typical sources of time-varying magnetic field intensities, examined salient field characteristics and illustrated correct survey methods. Our goal this month is to analyze data collected at a proposed site and answer the key question of whether or not the candidate site is, as far as magnetic fields go, acceptable for EM use. In the process of analyzing the magnetic field survey data we will define some of the interpretive techniques involved and observe the distinction between localized (a.c. power) and non-localized (geomagnetic) time-varying fields. Finally, we will discuss the implications of EM susceptibility threshold vs. measured field ratios when considering remedial site shielding.

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