Search results
Results from the WOW.Com Content Network
The Independent Atom Model (abbreviated to IAM), upon which the Multipole Model is based, is a method of charge density modelling. It relies on an assumption that electron distribution around the atom is isotropic, and that therefore charge density is dependent only on the distance from a nucleus.
The first PTF came from the study of Lyman Briggs and McLane (1907). They determined the wilting coefficient, which is defined as percentage water content of a soil when the plants growing in that soil are first reduced to a wilted condition from which they cannot recover in an approximately saturated atmosphere without the addition of water to the soil, as a function of particle-size:
Sediment cores analyzed for δ 15 N yield an historical record of such waste, with older samples at greater depths. δ 15 N is also used to measure food chain length and the trophic level of a given organism; high δ 15 N values are positively correlated with higher trophic levels; likewise, organisms low on the food chain generally exhibit ...
In addition to bonding, QTAIM allows the calculation of certain physical properties on a per-atom basis, by dividing space up into atomic volumes containing exactly one nucleus, which acts as a local attractor of the electron density. In QTAIM an atom is defined as a proper open system, i.e. a system that can share energy and electron density ...
In a simulation, the potential energy of an atom, , is given by [3] = (()) + (), where is the distance between atoms and , is a pair-wise potential function, is the contribution to the electron charge density from atom of type at the location of atom , and is an embedding function that represents the energy required to place atom of type into the electron cloud.
In geotechnical engineering, a nuclear densometer or soil density gauge is a field instrument used to determine the density of a compacted material. The device uses the interaction of gamma radiation with matter to measure density, either through direct transmission or the "backscatter" method. The device determines the density of material by ...
Roughly a third of all food is lost or wasted from the U.S. food supply each year and, with its big holiday meal as the centerpiece, Thanksgiving can be one of the most wasteful days of the year ...
Archaeological materials, such as bone, organic residues, hair, or sea shells, can serve as substrates for isotopic analysis. Carbon, nitrogen and zinc isotope ratios are used to investigate the diets of past people; these isotopic systems can be used with others, such as strontium or oxygen, to answer questions about population movements and cultural interactions, such as trade.