Fuel oil pollution control and additional maintenance required after burning it often outweigh the low cost of the fuel. Burning fuel oil, particularly residual fuel oil, produces uniformly higher carbon dioxide emissions than natural gas. Heavy fuel oils continue to be used in the boiler "lighting up" facility in many coal-fired power plants. This use is approximately analogous to using kindling to start a fire. Without performing this act it is difficult to begin the large-scale combustion process. The chief drawback to residual fuel oil is its high initial viscosity, particularly in the case of No. 6 oil, which requires a correctly
Phosphatic fossilization Formation presents a classic example of phosphatic fossilization: A refinement to viewing the internal structure of fossilized embryos uses specialized microscopic three-dimensional X-ray computed tomography, a kind of micro CAT scan. Phosphatic fossilization Phosphatic fossilization has occurred in unusual circumstances to preserve some extremely high-resolution microfossils in which careful preparation can even reveal preserved cellular structures. Such microscopic fossils are only visible under the scanning electron microscope. Large quantities of phosphate are required, either from seawater or from the tissues of the decaying organism. In some cases microbes control the phosphatization, and the remains of the microbes that fed on