In the Hornbostel-Sachs classification system, it is a membranophone. Drums consist of at least one membrane, called a drumhead or drum skin, that is stretched over a shell and struck, either directly with the player's hands, or with a drum stick, to produce sound.
Heat production can be calculated from a measurement of VO 2 and/or CO 2. Doubly-Labeled Water Doubly-labeled water contains isotopes of oxygen and of hydrogen. The technique involves the consumption by the patient of the doubly-labeled water then the measurement of the amount of isotope in the person after a washout period of 7- 14 days. Most of the hydrogen and oxygen isotopes are lost through excretion and evaporation, but some of the oxygen isotope equilibrates with carbon dioxide and is expired in air.
This healthy body water percentage chart will help you determine if you have enough water in your system. Many scales will tell you this value in seconds. Because your fat in your body has a lot of water in it, you have to first know how much fat you have in your body before you can then figure out what your healthy water content is. That is, if you say have 33% fat in your body, then you only need another 37% of water alone, because you have water in the fat. The scales don't count fat water as water, otherwise your numbers would get very confusing :)