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Population balance equation. Population balance equations (PBEs) have been introduced in several branches of modern science, mainly in Chemical Engineering, [1] to describe the evolution of a population of particles. This includes topics like crystallization, [2] leaching (metallurgy), [3][4] liquid–liquid extraction, gas-liquid dispersions ...
Population density is the number of people per unit of area, usually transcribed as "per square kilometer" or square mile, and which may include or exclude, for example, areas of water or glaciers. Commonly this is calculated for a county, city, country, another territory or the entire world. The world's population is around 8,000,000,000 [ 3 ...
Mulliken charges arise from the Mulliken population analysis [1] [2] and provide a means of estimating partial atomic charges from calculations carried out by the methods of computational chemistry, particularly those based on the linear combination of atomic orbitals molecular orbital method, and are routinely used as variables in linear regression (QSAR [3]) procedures. [4]
The number density (symbol: n or ρN) is an intensive quantity used to describe the degree of concentration of countable objects (particles, molecules, phonons, cells, galaxies, etc.) in physical space: three-dimensional volumetric number density, two-dimensional areal number density, or one-dimensional linear number density.
The rate at which a population increases in size if there are no density-dependent forces regulating the population is known as the intrinsic rate of increase. It is d N d t = r N {\displaystyle {\mathrm {d} N \over \mathrm {d} t}=rN} where the derivative d N / d t {\displaystyle dN/dt} is the rate of increase of the population, N is the ...
Population inversion. In physics, specifically statistical mechanics, a population inversion occurs while a system (such as a group of atoms or molecules) exists in a state in which more members of the system are in higher, excited states than in lower, unexcited energy states. It is called an "inversion" because in many familiar and commonly ...
The unobservable density function is thought of as the density according to which a large population is distributed; the data are usually thought of as a random sample from that population. [1] A variety of approaches to density estimation are used, including Parzen windows and a range of data clustering techniques, including vector quantization.
The map on the right uses population density. A properly normalized map will show variables independent of the size of the polygons. Normalization is the technique of deriving a spatially intensive variable from one or more spatially extensive variables, so that it can be appropriately used in a choropleth map. [ 3 ]