Humic acid (HA) was extracted by a hydrothermal method from Huolinhe lignite from Inner Mongolia. The effects of the alkali-to-carbon mass ratio. water-to-coal mass ratio. reaction temperature. https://www.roneverhart.com/2003-2005-HONDA-ACCORD-2-4L-4-Cylinder-Engine-Upper-Intake-Manifold-OEM/