ABSTRACT
In measurements, there are two basic concepts: static density measurements and dynamic (on-line) density measurements. Within each concept, there are many different methods employed. In general, static density measurements of fluids are well developed, precise, and have greater resolution than most dynamic techniques. Also, many static density measurement devices are computerized and come with appropriate hardware and software. Their uses can also be extended to applications such as the specific gravity measurements under low vapor pressures and density measurements of hazardous fluids. However, many alternative scales are offered by manufacturers, such as specific gravity, API gravity, Brix, Brine, etc. Hydrometers can be calibrated for different ranges for surface tensions and temperatures. The accuracy of the density measurement depends on the accuracy of the measurement of the intensity of the radiation and the path length d.
