Today, velocity of detonation can be measured with accuracy. Often, these variables are measured quantitatively. These parameters are usually measured in days. Alternatively, the thermal performance can be measured experimentally. It is commonly measured to in total length. Fluid barrels vary depending on what is being measured and where. Emissions may also be measured across shorter time periods. Emissions may be measured over long time periods. Methane is typically measured using gas chromatography. For example, many quantitative variables have been measured on plants. Each deflector measured high by wide by long, and weighed . This angle is usually measured in milliradians. Crosslinking is often measured by swelling tests. Eris has been measured at in diameter. In chemistry, heat amounts were often measured in calories.