[Chemical Engineering] Separation Processes_PT

From here, We need to understand what 'Starling‘s law and K-K equation state about'.

First of all, Starling's law states that the force of contraction. It depends on the length of muscle fibers of the heart. This intrinsic response of the heart is called Starling's law of the heart.
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If you look at this slide, you can see that graph, which is 'Starling's law of the heart.'

The length-tension relationship of a normal heart is shown in the lower curve.
In contrast, this increase in heart rate can dramatically increases cardiac output.

As mentioned before, an increase in a heart volume increases stroke (맥박) volume and excess volume. Therefore, we could say that the magnitude of fluid movement is dependent on the net balance of Starling forces across the endothelial barrier(내비장벽).

From this fact, We can conclude that the rate of fluid transport through the capillary walls can be modeled by Starling's law.
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Let's move on to the next slide.

----------------------------------------------------------------------------------------- Next one is about The Kedem and Katchalsky equations.

The Kedem-Katchalsky (K-K) equations, commonly and classically used to describe
the volume and solute flows of nonelectrolyte solutions(비전해질용액) across membranes.

However in biophysical practice, we usually have to deal with systems whose solutions are poorly mixed caused by effect of solute size, effect of solute charge and so on.
That's why in that system, we assume that the solutions on both sides are well mixed.

The modified K-K equation obtained here, which expresses the volume flow (Jv), includes the effect of boundary layers with varied concentrations in the case of poorly-mixed solutions.

Further more, their existences significantly reduces the stream of diluted substance (Js) and the volume stream(Jv). In order to describe mathematically these streams, it was necessary to transform the Kedem and Katchalsky classical equation into a more practical equation.
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In conclusion, Starling and Kedem-Katchalsky eqn. Both of them are describing Endothelial permeability(내피투수성). In addition, The application of the K-K practical equations is reduced to membrane systems with sufficiently diluted and well mixed solutions such as a glomerulus system.