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A polycarbonate is an oxocarbon dianion consisting of a chain of carbonate units, where successive carbonyl groups are directly linked to each other by shared additional oxygen atoms. That is, they are the conjugate bases of polycarbonic acids , the conceptual anhydrides of carbonic acid , or polymers of carbon dioxide .
Example Bjerrum plot: Change in carbonate system of seawater from ocean acidification.. A Bjerrum plot (named after Niels Bjerrum), sometimes also known as a Sillén diagram (after Lars Gunnar Sillén), or a Hägg diagram (after Gunnar Hägg) [1] is a graph of the concentrations of the different species of a polyprotic acid in a solution, as a function of pH, [2] when the solution is at ...
Polycarbonate is commonly used in eye protection, as well as in other projectile-resistant viewing and lighting applications that would normally indicate the use of glass, but require much higher impact-resistance. Polycarbonate lenses also protect the eye from UV light.
For example, if narrow molar mass distribution standards are available for polystyrene, these can be used to construct a calibration curve (typically vs. retention volume ) in eg. toluene at 40 °C. This calibration can then be used to determine the "polystyrene equivalent" molecular weight of a polyethylene sample if the Mark-Houwink ...
The principal limitation of the solubility parameter approach is that it applies only to associated solutions ("like dissolves like" or, technically speaking, positive deviations from Raoult's law); it cannot account for negative deviations from Raoult's law that result from effects such as solvation or the formation of electron donor ...
For example, if a part were to be loaded in tension until it was permanently deformed (plastically deformed), that would be considered one quarter cycle of low cycle fatigue, or LCF. In order to complete a full cycle the part would need to be deformed back into its original shape.
Hansen solubility parameters were developed by Charles M. Hansen in his Ph.D thesis in 1967 [1] [2] as a way of predicting if one material will dissolve in another and form a solution. [3] They are based on the idea that like dissolves like where one molecule is defined as being 'like' another if it bonds to itself in a similar way.
This is an energy balance which defines the position of the moving interface. Note that this evolving boundary is an unknown (hyper-)surface; hence, Stefan problems are examples of free boundary problems. Analogous problems occur, for example, in the study of porous media flow, mathematical finance and crystal growth from monomer solutions. [1]