Longitudinal reaction

The longitudinal reaction in the passing situations depended highly on the position of the pedestrian. A braking reaction is observed in... 

In turbulent flow, axial mixing is usually described in terms of turbulent diffusion or dispersion coefficients, from which cumulative residence time distribution functions can be computed. Davies (Turbulence Phenomena, Academic, New York, 1972, p. 93), gives Di = l.OlvRe for the longitudinal dispersion coefficient. Levenspiel (Chemical Reaction Engineering, 2d ed., Wiley, New York, 1972, pp. 253-278) discusses the relations among various residence time distribution functions, and the relation between dispersion coefficient and residence time distribution. 

Balance. If the center of mass of the projectile is not located extremely close to its longitudinal centerline, the center of pressure can form a couple with the inertial reaction through the center of mass, making the projectile tend to tumble in the barrel (Barker, 1985). Tumbling is prevented by the gun barrel, which exerts counteracting asymmetric forces on the projectile during its acceleration. These forces can lead to asymmetric wear of the projectile. If the center of mass is closer to one end of the projectile, which it nearly always is, the situation is unstable the wear increases the imbalance, which increases... 

We can characterize the mixed systems most easily in terms of the longitudinal dispersion model or in terms of the cascade of stirred tank reactors model. The maximum amount of mixing occurs for the cases where Q)L = oo or n = 1. In general, for reaction orders greater than unity, these models place a lower limit on the conversion that will be obtained in an actual reactor. The applications of these models are treated in Sections 11.2.2 and 11.2.3. 

The Longitudinal Dispersion Model in the Presence of Chemical Reaction... 

The physical situation in a fluidized bed reactor is obviously too complicated to be modeled by an ideal plug flow reactor or an ideal stirred tank reactor although, under certain conditions, either of these ideal models may provide a fair representation of the behavior of a fluidized bed reactor. In other cases, the behavior of the system can be characterized as plug flow modified by longitudinal dispersion, and the unidimensional pseudo homogeneous model (Section 12.7.2.1) can be employed to describe the fluidized bed reactor. As an alternative, a cascade of CSTR s (Section 11.1.3.2) may be used to model the fluidized bed reactor. Unfortunately, none of these models provides an adequate representation of reaction behavior in fluidized beds, particularly when there is appreciable bubble formation within the bed. This situation arises mainly because a knowledge of the residence time distribution of the gas in the bed is insuf-... 

This problem indicates the considerations that enter into the design of a tubular reactor for an endothermic reaction. The necessity of supplying thermal energy to the reactor contents at an elevated temperature implies that the heat transfer considerations will be particularly important in determining the longitudinal temperature profile of the reacting fluid. This problem is based on an article by Fair and Rase (1). 

A related phenomenon occurs if the reactions are carried out at low field outside, but where the samples are transferred immediately thereafter into the spectrometer for subsequent NMR analysis. This variety has been termed ALTADENA (Adiabatic Longitudinal Transport After Dissociation Engenders Net Alignment) [9]. Other authors [7] have since used the acronym PHIP as an alternative for the same phenomenon. 

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