Combustion: A combustion reaction involves a substance combining with an oxidizer, releasing a large amount of heat (exothermic) and produces a flame. The heat produced can make combustion self-sustaining. An oxidizer is a compound that takes electrons in a reaction and can promote or initiate combustion. Oxygen and chlorine are examples of oxidizers. When oxygen is available in sufficient amounts, complete combustion occurs. If a hydrocarbon undergoes complete combustion, carbon dioxide and water vapor are produced. Combustion reactions can be oxygen starved or can involve excess oxygen. In an oxygen starved combustion reaction, a combustion reaction has a limited oxygen supply and incomplete combustion occurs. In an environment of combustion in excess air, the amount of oxygen supplied to the combustion reaction is more than is needed for complete combustion and can lead to a hotter, faster burning fire.
The products of incomplete combustion (PICs) are different than the products of pyrolysis. Some of the products of incomplete combustion (PIC) of a hydrocarbon are gasses such as carbon monoxide, methane and polyaromatics because there is not enough oxygen to completely oxidize the hydrocarbon. Carbon in the form of soot or ash can also be a a product of incomplete combustion. Typically, a mixture of unreacted carbon char and ash remains in the products of pyrolysis. Char is a porous carbon structure that remains after the bonds are broken in the pyrolytic reaction and all the hydrogen and oxygen, along with some carbon is removed as a gas. Char is often defined as the solid residue after pyrolysis. Pyrolytic carbon is a material similar to graphite which is produced by the pyrolysis of carbon containing
compounds at very high temperatures.
Daubert Challenge: A
Daubert Challenge is a
particular type of motion made to the judge either before or during
litigation, in an effort to exclude the introduction of unqualified expert
witness testimony to the judge or jury during trial.
Heartcut: The various components of a mixture have different molecular sizes, molecular weights and boiling temperatures. Because they have different boiling temperatures, they can be separated by a process called fractionation and heart cutting.
Pyrolysis is the process of heating organic material at high temperatures in the absence of oxygen or any other oxidizer. The term pyrolyze is used when subjecting a substance to pyrolysis. Pyrolysis involves the simultaneous change of chemical composition and physical phase, and is irreversible. Pyrolysis is not combustion and the compounds produced by pyrolysis are generally different than those produced by combustion or incomplete combustion. Pyrolysis has been used since
ancient times for turning wood into charcoal. Charcoal is obtained by heating wood in the absence of air until its complete pyrolysis (carbonization) occurs, leaving only carbon and inorganic ash.
Rubber - Factice vs. Synthetic: Factice is vulcanized vegetable oil and is typically a springy type solid of friable consistency.
Vulcanizing from the manufacturers point of view is applying heat at a given temperature for a given time to cure the product so it takes up its shape. Curing involves the chemical reactions which occur in the rubber mixture to produce the crosslinking. Heating can be done in the mold using steam, or in autoclaves, ovens, typically using hot gases. One of the uses of factice is an additive as a processing aid in the manufacture of synthetic rubber. As a processing aid factice reduces tackiness of compounds during roll operations, improves processability and shortens mixing time, gives dimensional stability and smooth surface to compounds and can reduce die swell and shrinkage. As a softener and a dry plasticizer, factice can be useful to make low-hardness rubber products, absorbs liquid plasticizers and oils, prevents blooming, improves oil and solvent resistance. The two types of rubber in common use today are natural and synthetic. Natural rubber comes from the rubber tree (Hevea brasiliensis). Synthetic rubber is made by man from petrochemical feedstocks. Crude oil is the principal raw material. Polybutadiene synthetic rubber is widely employed in tire treads. Polybutadiene rubber generally consists of polybutadiene, and an elastomer (elastic polymer) built up by chemically linking multiple molecules of butadiene to form giant molecules, or polymers. 1,3-butadiene is a an industrial chemical with the formula C4H6. 1,3-Butadiene is typically a reactive colorless gas produced by the dehydrogenation of butane or butene or by the cracking of petroleum distillates. The gas is dissolved in hydrocarbon solvents and polymerized to polybutadiene. Polybutadiene rubber is sometimes notated as PBR.