Universal distinct element

FTASCA Consulting Group, Inc., 1996. UDEC, Universal Distinct Element Code, Version 3.0. 

Itasca Consulting Group (1998) 3DEC - universal distinct element code, Minneapolis... 

Sulfur is the tenth most abundant element in the universe thus it is an important datum for nucleosynthesis theories. It is not equally significant in terrestrial abundances because, owing to its rather high volatility, much ofitwas lost into space as the Earth formed. Sulfur is easily found on Earth, however, even in its pure elemental form, in which it is a pale-yellow, brittle solid. It melts near 113 °C, just above the boiling point of water. Sulfur was not recognized as a distinct element until 1777, by Lavoisier. It suddenly became much more important after the discovery of its use in gunpowder. 

A recent extension of the scope of SPE-GC concerns the use of atomic emission detection. With its distinct element selectivity, the atomic emission detector can provide information that is complementary to that of a mass-selective detector. An additional advantage of AED is that the response per mass unit of an element is more or less independent of the structure of the analyte of interest. This allows the use of the universal calibration concept [90,91], although this statement is... 

The simple body concept provided an almost universally accepted way of expressing chemical composition, but the conditional assignment of any body as simple carried with it a philosophic discomfort frequently expressed. Nearly every chemical writer of this period who mentioned the idea of elements or simple bodies also took the trouble to emphasize the distinction between simple body and the philosophical element. The conditional nature of simple body that made it operationally useful also allowed the indefinite expansion of their number. Nearly twenty new metals were discovered and identified between 1789 and 1810, raising plaintive cries that there were too many elements, together with the hope that ultimately their numbers would be reduced. In 1796, Nicolas-Louis Vauquelin was almost apologetic in reporting a new simple body from his analysis of the red lead of Siberia [lead chromate] ... 

The fact that uranium is capable of undergoing a process known as fission was discovered as an indirect result of the use of neutrons as projectiles in the production of artificial radioactive isotopes. At the University of Rome, the Italian physicist Enrico Fermi bombarded many different elements with neutrons and thereby produced many new radioactive isotopes. The use of neutrons as projectiles has the distinct advantage that the collision of these uncharged particles with... 

Models of planetary evolution assume that at the time of planetary formation the solar system had a single universal and well-mixed composition from which aU parts of the solar system were derived (see Podosek, 1978). Information as to the elemental and isotopic characteristics of this primordial composition is presently available from the Sun, meteorites, and the atmospheres of the giant planets (Wider, 2002). In the case of the Sun, distinction is usually made between the present-day composition, which is available via spectral analysis of the solar atmosphere and capture of the solar wind, either directly in space or by using metallic foU targets, and the proto-Sun (the composition at the time of planetary accretion) whereby the lunar regolith and/or meteorites are utilized as archives of ancient solar wind. As discussed below, the distinction is only really important for helium due to production of He by deuterium burning. 

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