Synapse uses the concept of "design categories" to design mixtures. The Design Categories Section is used to specify these categories.

The entered design categories initialize the number of components all candidates will have. For example, an aircraft anti-icing fluid design specified the following six design categories. (An aircraft anti-icing fluid is a fluid that is sprayed on aircraft surfaces in winter to prevent the accumulation of snow and ice. See USA Patent 07270767 for additional background information.)

Category	Function
Water	For product volume and to reduce flash point and environmental impact.
Depressant	Combined with water to produce a liquid having a low freezing point.
Surfactant	Ensures the fluid completely wets aircraft surfaces.
Thickener	Produces a shear-thinning viscosity sufficient to prevent drainage from aircraft surfaces.
Inhibitor	Prevents the corrision of metals by water and salts.
Dye	Colors the product for easy identification.

Once you enter the design categories, you will then use the other sections in the current mixture design to specify the chemicals contained within each category (see documentation on Category Chemicals Section) and the range of concentrations each category can have (see documentation on Category Concentration Limits Section).

For example, given a set of design categories, component chemicals and conentration limits, Synapse could generate the following candidates.

Category	Candidate 001	Candidate 002	Candidate 003
Water	Water 46.5%	Water 37.8%	Water 27.1%
Depressant	1,2-PG 50.0%	1,2 PG 60.0%	DPG 70.0%
Surfactant	PEG12a 1.5%	BR40a 1.0%	TG10 1.0%
Thickener	Welan 1.5%	XNG 0.5%	XNG 1.0%
Inhibitor	TT 0.4%	TT 0.6%	TT 0.8%
Dye	SG10 0.1%	SG33 0.1%	SG45 0.1%

Each candidate consists of six components having a specific concentration. One component and one concentration for each design category.

The Design Categories Section contains one large field - the Design Categories field. You use the Design Categories field to specify the categories that will be uses in your mixture design. Design Categories must be entered before you can enter further design details.

Clicking the left mouse button on the field's table control activates the edit dialog. (See documentation on the Design Categories Dialog for editing details.)

Topic	Description
Getting Started using Synapse	provides a quick tour of Synapse's capabilities including examples of chemical product design.
Designing Chemical Products	a short video demonstrating how to use Synapse to design candidate chemicals that satisfy a set of physical property and molecular structure constraints.