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.
Liquid iodine is an amazingly useful substance, finding applications around the home, in the research laboratory and at modern hospitals. Pure iodine is a bluish-black crystal, although it is rarely found in this form. Iodine is very soluble in nonpolar liquids such as hexane; however, iodine's solubility in water is limited. To increase solubility, iodine is mixed with an iodophor like povidone or an iodide such as potassium iodide. Video of the Day