Radio frequency electromagnetic radiation

NMR is an incredibly versatile tool that can be used for a wide array of applications, including determination of molecular structure, monitoring of molecular dynamics, chemical analysis, and imaging. NMR has found broad application in the food science and food processing areas (Belton et al., 1993, 1995, 1999 Colquhoun and Goodfellow, 1994 Eads, 1999 Gil et al., 1996 Hills, 1998 O Brien, 1992 Schmidt et al., 1996 Webb et al., 1995, 2001). The ability of NMR to quantify food properties and their spatiotemporal variation in a nondestructive, noninvasive manner is especially useful. In turn, these properties can then be related to the safety, stability, and quality of a food (Eads, 1999). Because food materials are transparent to the radio frequency electromagnetic radiation required in an NMR experiment, NMR can be used to probe virtually any type of food sample, from liquids, such as beverages, oils, and broth, to semisolids, such as cheese, mayonnaise, and bread, to solids, such as flour, powdered drink mixes, and potato chips. 

Electromagnetic radiation consists of a stream of photons. Each photon is made up of an electric field component and a magnetic field component, and these two components are mutually perpendicular. The frequency of a photon determines how fast the electric field component and magnetic field component will pulse, or beat. Radio-frequency electromagnetic radiation at 500 MHz will thus have a magnetic field component that beats 500 million times a second, by definition. 

Radio-frequency electromagnetic radiation can have two kinds of effect on the Mossbauer spectrum (Gonser 1981). It can result in a collapse of the split Mossbauer pattern, but it can also produce side bands in the spectrum on the basis of which a better identification of the atomic species can sometimes be achieved (Kopcewicz 1989). 

Initiation by Radio Frequency (RF) Radiation. RF radiation, ie, radio wave radar transmitters can, under certain circumstances, initiate electroexplosive devices. This topic will be discussed under Radio Frequency Radiation, Effects on Explosives. Also see articles on Electromagnetic Compatibility Electromagnetic Field Hazard, Simulated in Vol 5, pp E70-71 and Electric Blasting Caps and RF Energy in Vol 5, p E25-L... 

Berry et al. [54] employed guidelines for skin exposure to THz radiation (15 GHz to 115 THz) drawn from American National Standard for the Safe Use of Lasers (ANSI Z136.1) and from the IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields (C95.1). They concluded that the maximum permissible average beam power was 3 mW, suggesting that typical THz imaging systems are safe. 

Radio waves Electromagnetic radiation suitable for radio transmission in the range of frequencies from about 10 kHz to about 300 MHz. 

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