APPENDIX VIII
GLOSSARY OF SELECTED TERMS Altitude (degrees) – The angular distance between the horizon and the sun’s position above the horizon.
Azimuth (degrees) – The angular distance along the horizon between the projected position of the sun and solar (true) south.
Density, ρ (lb/ft3) – Mass per unit volume.
Extinction coefficient (dimensionless) – The measure of the rate of reduction of transmitted light by means of scattering and absorption for a specified medium.
Heat capacity (Btu/°F ft2) – The amount of thermal energy (heat) that can be stored in a material per unit of volume. The heat capacity is the product of a material’s density and specific heat.
Index of refraction (dimensionless) – The ratio of the speed of light in a vacuum to the speed of light in a specified medium.
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