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Its bank density (the density of a coal seam prior to breaking up during mining) is about 1346 kg/m 3 (84 lb/ft 3) while the bulk density of extracted coal is up to 833 kg/m 3 (52 lb/ft 3). [12] Bituminous coal characteristically burns with a smoky flame and softens and swells during combustion. [13]
Anthracite, also known as hard coal and black coal, is a hard, compact variety of coal that has a submetallic lustre.It has the highest carbon content, the fewest impurities, and the highest energy density of all types of coal and is the highest ranking of coals.
Coal plies and particles have different relative densities, determined by vitrinite content, rank, ash value/mineral content and porosity. Coal is usually washed by passing it over a bath of liquid of known density. This removes high-ash value particle and increases the saleability of the coal as well as its energy content per unit volume.
The energy density of coal is roughly 24 megajoules per kilogram [80] (approximately 6.7 kilowatt-hours per kg). For a coal power plant with a 40% efficiency, it takes an estimated 325 kg (717 lb) of coal to power a 100 W lightbulb for one year.
The contribution of the muscle to the specific heat of the body is approximately 47%, and the contribution of the fat and skin is approximately 24%. The specific heat of tissues range from ~0.7 kJ · kg−1 · °C−1 for tooth (enamel) to 4.2 kJ · kg−1 · °C−1 for eye (sclera). [13]
— "Values ranging from 21.3 to 21.5 gm/cm 3 at 20 °C have been reported for the density of annealed platinum; the best value being about 21.45 gm/cm 3 at 20 °C." 21.46 g/cm 3 — Rose, T. Kirke. The Precious Metals, Comprising Gold, Silver and Platinum .
5.56 × 45 mm NATO bullet muzzle energy density [clarification needed] 0.4: 3.2: battery, Nickel–metal hydride (NiMH), low power design as used in consumer batteries [29] 0.4: 1.55: Liquid Nitrogen: 0.349: Water – Enthalpy of Fusion: 0.334: 0.334: battery, Zinc–Bromine flow (ZnBr) [30] 0.27: battery, Nickel–metal hydride (NiMH), High ...
The heat content of sub-bituminous coals range from 8300 to 11,500 BTu/lb or 19.3 to 26.7 M J/kg. Their relatively low density and high water content renders some types of sub-bituminous coals susceptible to spontaneous combustion if not packed densely during storage in order to exclude free air flow.