brownian motion

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brown·i·an move·ment

erratic, nondirectional, zigzag movement observed by ultramicroscope in certain colloidal solutions and by microscope in suspensions of light particulate matter that results from the jostling or bumping of the larger particles by the molecules in the suspending medium which are regarded as being in continuous motion.
[Robert Brown]
Farlex Partner Medical Dictionary © Farlex 2012


Robert, English botanist, 1773-1858.
brownian motion - Synonym(s): brownian movement
brownian movement - rapid random motion of small particles in suspension. Synonym(s): brownian motion; brownian-Zsigmondy movement; molecular movement; pedesis
brownian-Zsigmondy movement - Synonym(s): brownian movement
Medical Eponyms © Farlex 2012
References in periodicals archive ?
The concept of RWK model is the ideal mathematical state of Brownian motion. Therefore, we assume that all nodes perform Brownian motion and each node moves independently.
The effect of Brownian motion parameter Nb on the dimensionless temperature and the dimensionless nanoparticle volume fraction is plotted in Figure 6 (Figures 6(a) and 6(b), respectively).
This model also takes into account thermal conductivity related to Brownian motion.
The system of ordinary differential equations (11) subject to the boundary conditions (12) was solved numerically using the package bvp4c in MATLAB for different values of parameters: the stretching/shrinking parameter in x-direction [[lambda].sub.1], suction S, Brownian motion parameter Nb, thermophoresis parameter Nt, and Lewis number Le.
Visual observations of Brownian motion indicate that each nanoparticle can be modeled as having a local periodic motion within the suspension, as shown in Figure 1.Asillustrated, points A and C can be used to represent the farthest points of local periodic motion, and point B is the location at which the local periodic motion has the highest velocity.
A rise in [N.sub.t] at lower values of Le leads to a drop in concentration rate, while for higher Lewis numbers, concentration rate takes an increasing trend except for some values of low thermophoresis and Brownian motion. Furthermore, as [N.sub.b] increases, the -[phi]'(0)'s variation is dwindled down which is more suppressed as Lewis number increases.
Since geometric Brownian motion will not generate a negative value from the positive starting value, it does not fit the [k.sub.t] process by itself.
Since the sample paths of the Brownian motion are nowhere differentiable, we cannot use the ordinary integral to calculate it.
Here [O.sub.0] [subset] O [subset] [R.sup.d] are open, bounded subsets, [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] are linearly independent Brownian motions in a probability space {[OMEGA], P, F}, a = a(t, [xi]), b = b(t, [xi]), [mu] = [mu](t, [xi]) are given continuous functions on [0, T] x O.
Under the Brownian motion that is being exhibited, small molecules move quickly, and large molecules move slowly.
Brownian motion B(t), where t [member of] T, is a stochastic process with the following properties.
However, unavoidable errors of measurement (in the aspect ratio determination as well as in the viscosity measurement) do not permit to seriously assess the influence of Brownian motion. Moreover, for such a precise assessment of this kind the width of the size distribution must be taken into account.