Heartburn is often triggered by foods. This is because certain substances irritate the esophagus or weaken the lower esophageal sphincter (LES), which prevents the backward flow of stomach contents that causes reflux. Triggers can include: 1  alcohol. 2  caffeinated products, such as coffee, soda, and tea. 3  chocolate. 4  citrus fruits. 5  garlic. 6  fatty foods. 7  onions.
Testing specific gravity of fuel. Specific gravity is the ratio of the density of a substance to the density of a reference substance; equivalently, it is the ratio of the mass of a substance to the mass of a reference substance for the same given volume.
Specific Gravity, also known as SG, is a measurement that determines the density of minerals. Two minerals may be the same size, but their weight may be very different. The specific gravity of a mineral determines how heavy it is by its relative weight to water. The specific gravity value is expressed upon how much greater the weight of the mineral is to an equal amount of water.