What is Kawakita equation?

The Kawakita equation. The equation is:(1) P a C = 1 ab + P a a where C is the relative volume decrease, i.e.:(2) C= V 0 −V V 0 and a and b are constants. It can be seen that a plot of Pa/C against P should give a straight line from which the constants, a and b, can be derived.

What is Heckel plot?

In 1961 Heckel postulated a linear relationship between the relative porosity (inverse density) of a powder and the applied pressure. Large values of the Heckel constant indicate susceptibility to plastic deformation at low pressures, when the tablet strength depends on the particle size of the original powder.

What is Heckel analysis?

The Heckel equation is one of the most useful equations for describing the compaction properties of pharmaceutical powders. Important material properties (e.g., yield strength) of powders can be derived using Heckel analysis. Two types of Heckel analysis are in common use.

What is Heckel plot equation?

Achieving the correct balance of plastic and brittle materials in a formulation is critical to ensure adequate tablet strength is achieved therefore classifying materials using the Heckel equation is attractive. The model proposed by Heckel [5] is represented by the following. equation: ln(1/1-D)=K•P+A.

What is difference between compaction and compression?

Compression is a process of compressing, or increase in density or lessening in the bulk volume of granules or powder. Compaction is the process of alteration of powders into a coherent specimen or compacting powder or granules.

What is Heckels equation?

What does the Heckel equation measure?

The Heckel equation was chosen since it is one of most widely used and accepted tools for the analysis of powder compression, and its 1/K parameter has been used to characterise powder plasticity and is thought to represent the yield stress of the powder system.

What is Heckel equation in physical pharmaceutics?

What does 95% compaction mean?

95% compaction means that the soil on the construction site has been compacted to 95% of the maximum density achieved in the lab. It means that when you conduct compaction test(in the laboratory) on a small soil sample of a particular site. You get some value of maximum dry unit weight at certain moisture content.

What is compaction profile?

Definition › Compaction profiles are hysteresis curves that establish the relationship between axial pressure and radial pressure. › In the compaction cycle, two forces are considered 1. Axial force: This vertical component is applied by the upper punch during compression.

What is the Heckel equation?

Heckel (1961a) developed his equation by assuming similarity to a first-order chemical reaction, where the concentration is substituted with porosity and the time with pressure. (1) d D/ d P=K ∗ (1 − D) where P is the pressure, D the relative density of the compact and K is a constant.

How are the Heckel and Kawakita equations similar?

It is then shown mathematically that if a pressure dependent term is used in the Heckel equation then the resulting modified equation is very similar to the Kawakita one and, in fact, becomes identical in form for a particular, likely value of the pressure dependency term.

How to find the formula for porosity of water?

Porosity = (Wt of wet memb-wt of dry memb)density polymer/ (Wt of wet memb-wt of dry memb)density polymer+wt of dry memb x density of water. may be it will help you. In formula of porosity is not weights – Only volumes!

What is the formula for bulk density and porosity?

I had known that the formula to calculate them. The formula for bulk density is (mass of dry soil) / (total volume of soil), 1 – (bulk density/particle density) for porosity, and (volume of pores) / (volume of solids) for void ratio. However, I can’t find out how to calculate them only with particle diameter and particle density.