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Abundance (atom fraction) of the chemical elements in Earth's upper continental crust as a function of atomic number; [5] siderophiles shown in yellow. Graphs of abundance against atomic number can reveal patterns relating abundance to stellar nucleosynthesis and geochemistry.
The abundance of the chemical elements is a measure of the occurrences of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (in commercial contexts often called weight fraction), by mole fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by volume fraction.
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Carbon (6 C) has 14 known isotopes, from 8 C to 20 C as well as 22 C, of which 12 C and 13 C are stable. The longest-lived radioisotope is 14 C, with a half-life of 5.70(3) × 10 3 years. This is also the only carbon radioisotope found in nature, as trace quantities are formed cosmogenically by the reaction 14 N + n → 14 C + 1 H. The most ...
Three graphs portray the evolution of its peatland carbon content over the past 20,000 years, as reconstructed from three peat cores. In 2017, it was discovered that 40% of the Cuvette Centrale wetlands are underlain with a dense layer of peat, which contains around 30 petagrams (billions of tons) of carbon. This amounts to 28% of all tropical ...
Graph homomorphism problem [3]: GT52 Graph partition into subgraphs of specific types (triangles, isomorphic subgraphs, Hamiltonian subgraphs, forests, perfect matchings) are known NP-complete. Partition into cliques is the same problem as coloring the complement of the given graph. A related problem is to find a partition that is optimal terms ...
For example green bonds, carbon offsetting, and payment for ecosystem services are some promoted solutions. There is considerable innovation in this area. Transfer of solutions that were not developed specifically for climate finance is also taking place, such as public–private partnerships and blended finance.
Alekseenko V.A., Alekseenko A.V. (2013) Chemical elements in geochemical systems. The abundances in urban soils. Publishing House of Southern Federal University, Rostov-on-Don (388 pp., in Russian with English Abstract). ISBN 978-5-9275-1095-5; Vladimir Alekseenko, Alexey Alekseenko (2014) The abundances of chemical elements in urban soils ...