Polychlorinated Biphenyl (PCBs) Polychlorinated Biphenyl (PCBs): Polychlorinated Biphenyl (PCBs) are highly toxic human-engineered chlorinated hydrocarbons that have been used around the world as enhancers to hydraulic oil and electrical insulators. PCBs were applied for maintaining low flammability rates, high boiling points, and stronger chemical stability. As of 1979, PCBs have been banned from use in…

Critical Void Ratio The “Critical Void Ratio,” in soil science and geology, represents the final void ratio of a soil sample, at ultimate strength. And Critical Void Ratio is achieved by the loose and dense samples of the same soil post-shearing.

Gravel Blanket in Methane Mitigation A gravel blanket is a 2-inch or 4-inch thick layer of gravel, sand, or approved material that transmits methane soil gas to the horizontal sub-slab perforated pipes and verticle vent riser of a passive methane mitigation system.

Mafic Definition In geology, “mafic” is a term that describes an igneous rock that has an abundance of darker color minerals.

Runoff (R) The term “Runoff” (R) in hydrogeology and geology refers to the part of rainfall which accumulates on the ground surface and naturally forms into flowing streams.

Rigidity Definition Rigidity – In geotechnical engineering and engineering geology, rigidity represents the ratio of the shear stress and the amount of angular rotation that it produces, within a rock sample.