Kirchhoff's law of thermal radiation rarefied material such as air, or transparent material, through which observations can be made. The interface is not a material body and can neither emit nor absorb. It is a mathematical surface belonging jointly to the two media that touch it. It is the site of refraction of radiation that penetrates it and of reflection of radiation that does not. As such it obeys the Helmholtz reciprocity principle. The opaque body is considered to have a material interior that absorbs all and scatters or transmits none of the radiation that reaches it through refraction at the interface. In this sense
Sound of a Living Heart Sound of a Living Heart Sound of a Living Heart is tenth studio album by JJ Heller. Stone Table Records alongside Sparrow Records released the album on August 21, 2015. Kevin Sparkman, indicating in a three and a half star review for "CCM Magazine", describes, "Heller continues her proven formula of innocent melodies, heart moving lyrics, and inviting musical moments." Awarding the album four stars from Jesus Freak Hideout, Mark D. Geil states, ""Sound of a Living Heart" is an encouraging sign of a continued upward trajectory." Jay Heilman, reviewing the album for Christian Music Review, writes, he's "highly impressed..."Sound