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Mechanics of gelation describes processes relevant to sol-gel process. In a static sense, the fundamental difference between a liquid and a solid is that the solid has elastic resistance against a shearing stress while a liquid does not. Thus, a simple liquid will not typically support a transverse acoustic phonon, or shear wave. Gels have been ...
CMC serves to both thicken the solution and add a lubricating effect, and often silicone-based lubricants are added for additional lubrication. The most familiar example of this type of lubricant, used as a surgical and personal lubricant , is K-Y Jelly .
Both gas and liquid lubricants can transfer heat. However, liquid lubricants are much more effective on account of their high specific heat capacity. Typically the liquid lubricant is constantly circulated to and from a cooler part of the system, although lubricants may be used to warm as well as to cool when a regulated temperature is required.
Silicone grease is widely used as a temporary sealant and a lubricant for interconnecting ground glass joints, as is typically used in laboratory glassware.Although silicones are normally assumed to be chemically inert, several historically significant compounds have resulted from unintended reactions with silicones.
The properties that are sought after in a good cutting fluid are the ability to: Keep the workpiece at a stable temperature (critical when working to close tolerances). Very warm is acceptable, but extremely hot or alternating hot-and-cold are avoided. Maximize the life of the cutting tip by lubricating the working edge and reducing tip welding.
An upturned vial of hair gel Silica gel. A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. [1] [2] Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady state, although the liquid phase may still diffuse through this system.
These may be liquid solutions (e.g. in aqueous solution), or solid solutions (e.g. a substance which has been plasticized). [ 2 ] The introduction into the polymer of small amounts of a solvent ( plasticizer ) reduces the temperature of glass transition , the yield temperature , and the viscosity of a melt .
Some types are synthetic liquid lubricants that have been used in the aerospace industry for over 30 years. [1] The main properties of PFPE are being temperature resistant between −58 °C (215 K) and 257 °C (530 K) (depending on specific composites), having very low outgassing compared to other fluids ( vapour pressure of 6 × 10 −8 Torr ...