Artificial radiation sources

Riehl and Maupin (23) define indoor lighting as artificial and natural light, neither a well-defined term. There are many different types of artificial radiation sources, and natural light is an undefined term. More correctly, their original statement should state it is a combination of "window-glass filtered" daylight and that from an artificial source. 

Average equivalent dose rates due to artificial radiation sources are listed in Table 22.9. These dose rates originate from application of X rays and radionuchdes for diagnostic and therapeutic purposes, from various radiation sources applied in daily life and from radioactive fall-out. 

Table 22.9. Radiation exposure by artificial radiation sources.

Eighty percent of typical human exposure comes from natural sources and 20 percent comes from artificial radiation sources, primarily medical X-rays. ... 

Measurements of ionizing radiation and radionuclides in foods and environmental samples are required for the assessment of exposure to both natural and artificial radiation sources, determination of compliance with government regulations, and studies of the movement and retention of artificial radionuclides in food and environmental media and of the composition of the natural radiation enviromnent. 

Figure 58A-C shows that the heat source promoting the drying process changes during the course of the batch combustion. At times to and ti there is an artificial heat source located in the over-bed section. At time t2 the flaming combustion has started. The flames feed back heat to the bed by means of radiation. At time t3 the basic heat flow comes from the char combustion and the ignition front, by means of conduction and radiation. [12,24]...

The development of the relationships between scattered light and aerosols has stimulated the use of radiation transfer theory for remote sensing of particles in planetary atmospheres. Highly sophisticated experimental and theoretical techniques have emerged for the interpretation of observations of sunlight and artificial light sources in the earth s atmosphere. A description of their application depends on further development of the concepts of radiant energy transfer. 

Guillermo A. Lemarchand, Detectability of extraterrestrial technological activities, http / /www.coseti.org/lemarch 1. htm. See also, Freeman Dyson, Search for artificial stellar sources of infrared radiation, Science 131 1667-1668 (1959) Freeman Dyson, The search for extraterrestrial technology, in Perspectives in Modern Physics (Essays in Honor of Hans Bethe), ed. R. E. Marshak (New York John Wiley Sons, 1966). 

The impact of electromagnetic radiation, especially of UV radiation, on the human skin and on the eye may lead to severe adverse effects (see Fig. 2-4) including skin cancer, severe skin burning, conjunctivitis or cataract formation. Hence, appropriate protective measures must be considered while working with artificial radiant sources. This includes UV-blocking eyewear and face wear. Never look directly and unprotected at an operating UV or VUV lamp ... 

Radiation sources are treated in the above bibliography. One book deals exclusively with this subject a section is devoted to health hazards and protection from radiation. Two types of source are available, those from natural or artificial radioisotopes produced in nuclear reactors and those from a particle accelerator. The first includes nuclear recoil processes which are used for studying hot atom displacement reactions in the gas phase. 

It is well known that the spectral distribution and irradiance of the solar radiation at the Earth s surface depend on the location and is subjected to seasonal and diurnal variations. Therefore, a reference spectrum is needed as a basis for comparison with the spectral energy distribution of artificial light sources. Data from CIE No. 15 1971 (colorimetry official recommendations of the International Commission on Illumination) that recommend a standard illuminant D65 with a scheduled color temperature of approximately 6500 K have been used as a basis over the years. 

SPECTRAL DISTRIBUTIONS OF ARTIFICIAL LIGHT SOURCES PROPOSED FOR DRUG PHOTOSTABILITY TESTS COMPARED WITH GLOBAL RADIATION BEHIND WINDOW GLASS... 

UV radiation originating from sunlight or artificial light sources results in substantial degradation of many commercial polymeric substrates. Degradation manifested as discoloration, embrittlement, cracking, and loss of other physical properties seriously reduces the useful lifetime and potential applications of polymeric materials. 

The origin of radiation sources leads to either natural or artificial radioactivity. 

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