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Specific energy absorption rate (SAR) averaged over the whole body or over parts of the body, is defined as the rate at which energy is absorbed per unit mass of body tissue and is expressed in watts per kilogram (W/kg). Whole body SAR is a widely accepted measure for relating adverse thermal effects to RF exposure. [9]
Parts-per-million cube of relative abundance by mass of elements in an average adult human body down to 1 ppm. About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium ...
The typical human body contains roughly 0.1 μCi (14 mg) of naturally occurring potassium-40. A human body containing 16 kg (35 lb) of carbon (see Composition of the human body) would also have about 24 nanograms or 0.1 μCi of carbon-14. Together, these would result in a total of approximately 0.2 μCi or 7400 decays per second inside the ...
Thermal radiation refers not only to the radiation itself, but also the process by which the surface of an object radiates its thermal energy in the form of black-body radiation. Infrared or red radiation from a common household radiator or electric heater is an example of thermal radiation, as is the heat emitted by an operating incandescent ...
For organ dose calculations, NASA uses the model of Billings et al. [23] to represent the self-shielding of the human body in a water-equivalent mass approximation. Consideration of the orientation of the human body relative to vehicle shielding should be made if it is known, especially for SPEs [24]
Dose equivalent calculates the effect of radiation on human tissue. [4] This is done using tissue weighting factor, which takes into account how each tissue in the body has different sensitivity to radiation. [4] The effective dose is the risk of radiation averaged over the entire body. [4] Ionizing radiation is known to cause cancer in humans. [4]
Water is far more prevalent in the outer Solar System, beyond a point called the frost line, where the Sun's radiation is too weak to vaporize solid and liquid water (as well as other elements and chemical compounds with relatively low melting points, such as methane and ammonia). In the inner Solar System, planets, asteroids, and moons formed ...
Two of the essential elements that make up the human body, namely potassium and carbon, have radioactive isotopes that add significantly to our background radiation dose. An average human contains about 17 milligrams of potassium-40 (40 K) and about 24 nanograms (10 −9 g) of carbon-14 (14 C), [17] (half-life 5,730 years). Excluding internal ...