Why is shape important?

Shape parameters such as Circularity, Convexity and Elongation provide the user with a series of highly sensitive tools in order to identify and quantify subtle variations in particle shape and provide a “fingerprint” of each sample. Each parameter is usually normalized between 0 and 1 in order to provide quick and easy comparability. Traditional qualitative human descriptions such as “jagged”, “smooth” or “needlelike” can be accurately quantified and hence correlated against important process or end-product variables such as flowability, active area and grinding efficiency.

Circularity is a measure of the closeness to a perfect circle. Circularity is sensitive to both changes in overall form and surface roughness.	Circularity =1	Circularity =0.47	Circularity =0.89	Circularity =0.52	Circularity =0.47	Circularity =0.21
Convexity is a measure ofthe surface roughness of a particle. Convexity is sensitive to changes insurface roughness but not overall form.	Convexity =1	Convexity =1	Convexity =1	Convexity =1	Convexity =0.70	Convexity =0.73
Elongation is a measure of the length-width relationship. Elongation is unaffected by surface roughnes - a smooth elipse has a similar eongation as a spiky elipse of similar aspect ratio.	Elongation =0	Elongation =0.82	Elongation =0	Elongation =0.79	Elongation =0.24	Elongation =0.83

Image analysis systems from Malvern:

Malvern offers three image analysis systems. These image analysis systems have been developed specifically for routine and repeatable particle size and particle shape analysis. The choice of instruments depends upon the nature of the application and sample form:

	Morphologi G3 - High sensitivity particle analyzer The Morphologi G3 is based on automated microscopy and enables characterization of particle size, particle shape and particle count in wet and dry materials in the range 0.5µm to 3000µm.
	Sysmex FPIA-3000 - for wet samples (suspensions and emulsions). The Sysmex FPIA-3000 is based upon flow cytometry and enables characterization of particle size and particle shape of wet materials in the range 0.8µm to 300µm.