Search results
Results from the WOW.Com Content Network
The momentum transfer plays an important role in the evaluation of neutron, X-ray, and electron diffraction for the investigation of condensed matter. Laue-Bragg diffraction occurs on the atomic crystal lattice, conserves the wave energy and thus is called elastic scattering, where the wave numbers final and incident particles, and , respectively, are equal and just the direction changes by a ...
Some of the most common examples of transport analysis in engineering are seen in the fields of process, chemical, biological, [1] and mechanical engineering, but the subject is a fundamental component of the curriculum in all disciplines involved in any way with fluid mechanics, heat transfer, and mass transfer.
In physics, and especially scattering theory, the momentum-transfer cross section (sometimes known as the momentum-transport cross section [1]) is an effective scattering cross section useful for describing the average momentum transferred from a particle when it collides with a target. Essentially, it contains all the information about a ...
This leads for example to an increase in the ratio of 234 U to 238 U in certain cases, which can be exploited in dating (see Uranium–thorium dating). [ 3 ] [ 4 ] In some cases, quantum effects can forbid momentum transfer to an individual nucleus, and momentum is transferred to the crystal lattice as a whole (see Mössbauer effect ).
For example, the mobility of the sodium ion (Na +) in water at 25 °C is 5.19 × 10 −8 m 2 /(V·s). [1] This means that a sodium ion in an electric field of 1 V/m would have an average drift velocity of 5.19 × 10 −8 m/s. Such values can be obtained from measurements of ionic conductivity in solution.
In fluid dynamics, the mixing length model is a method attempting to describe momentum transfer by turbulence Reynolds stresses within a Newtonian fluid boundary layer by means of an eddy viscosity. The model was developed by Ludwig Prandtl in the early 20th century. [ 1 ]
In Newtonian mechanics, momentum (pl.: momenta or momentums; more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction.
A general momentum equation is obtained when the conservation relation is applied to momentum. When the intensive property φ is considered as the mass flux (also momentum density), that is, the product of mass density and flow velocity ρu, by substitution into the general continuity equation: