What happens in penetration theory?

The theory states that closeness (penetration) develops if communication begins at relatively shallow non-intimate levels and moves in gradual and orderly fashion to deeper more personal levels. The theory proposes that relationships get more intimate over time when people disclose more information about themselves.

Who developed mass transfer penetration theory?

Higbie
Penetration theories originated with Higbie (1935) who used the equation for unsteady conduction to model the transport process in jets and packed columns. edge of the laminar boundary layer and is a time scale for the diffusion process.

What are the mass transfer processes?

Mass transfer is the net movement of mass from one location, usually meaning stream, phase, fraction or component, to another. Mass transfer occurs in many processes, such as absorption, evaporation, drying, precipitation, membrane filtration, and distillation.

What are the three regions of mass transfer?

Depending on the conditions, the nature, and the forces responsible for mass transfer, four basic types are distinguished: (1) diffusion in a quiescent medium, (2) mass transfer in laminar flow, (3) mass transfer in the turbulent flow, and (4) mass exchange between phases.

What is the difference between two film theory and penetration theory of mass transfer?

The film theory assumes that there is a region in which steady state molecular transfer is controlling; the penetration theory as- sumes that the interface is continuously replaced by eddies and that unsteady state molecular transfer into the eddies controls the transfer in this region.

What is social penetration theory examples?

For example, if two acquaintances meet at a rally for college democrats, at this stage their conversations might focus on involvement in politics, favorite candidates, and attitudes about political issues. In this stage, the personality begins to emerge.

What do you mean by Sherwood number?

The Sherwood number (Sh) (also called the mass transfer Nusselt number) is a dimensionless number used in mass-transfer operation. It represents the ratio of the convective mass transfer to the rate of diffusive mass transport, and is named in honor of Thomas Kilgore Sherwood.

Why is mass transfer important in separation processes?

1 As mentioned above, separation requires that mass be transported from one location to another. It is important to remember that bulk flow and mass transfer due to convection may create the essential concentration gradient for diffusion and thus play a significant role in the separation process.

What are the mechanism of mass transfer by diffusion and convection?

Convective mass transfer is really diffusion (the random movement of molecules) in combination with advection (molecules being carried along with the motion of the fluid). To better understand mass transfer via convection, it is important to consider boundary layers in fluids flowing over surfaces.

Is DAB equal to DBA?

Now we define the mass diffusivity DAB= DBA in a binary system in an analogous fashion: This is Fick’s first law of diffusion,1 written in terms of the molar diffusion flux JA*.

What is liquid liquid mass transfer?

1.4. Liquid mass transfer or convection coefficient is a flow dependent parameter, which is evaluated by use of empirical and semiempirical correlations. One of the most well-known correlations for use in water treatment situations is the following (Chern and Chien, 2002): (59)

Why is the social penetration theory important?

The social penetration theory gives a possibility of differentiation between the different types and forms of the relationships by providing the notions of personality breadth and personality depth. The theory also gives a description of the different phases involved in a relationship.

What is pen penetration theory?

Penetration theory is one of the mass transfer theories among Film Theory, Surface Renewal Theory, and Boundary Layer Theory. Penetration theory was first proposed by R. Higbie in 1935 and the theory is called Higbie’s penetration theory. Most of the industrial processes of mass transfer are unsteady state process.

What is danckwert’s penetration theory?

For the mass transfer in liquid phase, Danckwert (1951) modified the Higbie’s penetration theory. He stated that a portion of the mass transfer surface is replaced with a new surface by the motion of eddies near the surface and proposed the following assumptions:

What are the basic assumptions of the penetration theory?

Basic assumptions of the penetration theory are as follows: 1) Unsteady state mass transfer occurs to a liquid element so long it is in contact with the bubbles or other phase 2) Equilibrium exists at gas-liquid interface 3) Each of liquid elements stays in contact with the gas for same period of time Figure 3.4: Schematic of penetration model.

What is the process of mass transfer?

Most of the industrial processes of mass transfer are unsteady state processes where the gas-liquid contact time is too short to achieve steady state condition. In the absorption of gases from bubbles or absorption by wetted-wall columns, the mass transfer surface is formed instantaneously and transient diffusion of the material takes place.