Lecture 3 Assignment 1. In addition to reading through Chapter 1 , read one paper on the exposures that you get from a low frequency source and write up a one page summary. Also you should start looking for papers on a topic you want to follow up on and write a one page summary of it. 2. This is due next Monday

Bioelectromagnetics ECEN 5341/4341 Lecture 3-4 1. Environmental and Occupationally Encountered Electromagnetic Fields 2. The objective is to get a feel for the size of both the natural fields we are exposed to and the size of the fields that we are now exposed to resulting from the wide spread use of electricity.

Atmospheric Sources 1. Static and ELF (0 to 3khz) 2. Earth’s Static Magnetic Fields range from 24μT to 65μT with variation up to about 1μT with the Northern Lights over several minutes 3. Electric fields Static 100 to 300V/m with the earth negative. Up to 100kV/m in thunderstorms.

Natural EM Power Density at the Earths Surface

B Field for Underwater Cable Normal load 400A shielded so no E field outside

High Voltage AC Lines Standards in US limit Fields to 1 to 5kV/m

Magnetic fields from Power Lines as a Function of Distance

The Effects of Power Pole Configurations and Phasing on Magnetic Fields

1

Some Typical Magnetic and Electric Field Strengths vs. Distance

Fourier Spectrum of A Current Wave Form

Typical Magnetic Field Exposure Levels At Home

1

Variations with time of Day

Variations in Magnetic Field Exposures Over the Course of a Day

Some Current Wave Forms

The Fourier Spectra of 1.7

Lecture 4 January 25, 2017 Two Reference Formats. Brocklehurst B, McLauchlan K. 1996. Free radical mechanism for the effects of environmental electromagnetic fields on biological systems. Int J Radiat Biol 69:3–24. [28] K. Wang and T. Ritz, “Zeeman resonances for radical-pair reactions in weak static magnetic fields,” Mol. Phys., vol. 104, no. 10–11, pp. 1649–1658, 2006.

Magnetic Fields Around Appliances

1

Wave Shapes Near Fluorescent Light

Common Exposures

Exposures on Electric Trains

Electric Field Scaling and Induced Currents

Induced Electric Fields

A More Complete Model

1

Electric and Magnetic Induced Current Densities

Internally Generated Voltages

1

Lecture 5 January 27,2017

Sources of Intermediate and Radio Frequency Fields 1. Scanners , Libraries, Airport Security 920MHz , B = 10µT and Deactivate at 50-60Hz 500µT 2. Video Display Terminals, VDT, Cathode Ray Tubes CRT Up to 20KV inside the Tube, ≈10V/m at 0.5m

Computer Display Fields 1

RF Sources 2. RF heaters for sealing plastic etc. 3. RF Transmission Short Wave 2 -27MHz 3-20V/m at 10’s of meters. 4. Radio TV 5. Base Stations and Cell Phones, WiFi

TV and Base Stations

Exposure Levels 1. US average about 50µW/m2 to 100µW/m2 2. We have measure E =1 to 2 V/m in Boulder, peak power density < 10 mW/m2 3. Peak Power from transmitter about50 KW 4. Radar Peak at Megawatts, over the horizon

Frequencies