| second law of thermodynamics | <physics> All of the chemical and physical processes in a closed system tend to drive that system toward maximum entropy. Clausius statement: No device can operate in a cycle and allow heat to transfer from a colder body to a hotter body unless other compensating activities are taking place. Kelvin-Planck statement: no device can operate in a constant-temperature cycle and convert the heat it receives into work, unless other other compensating activities are taking place. (09 Oct 1997) |
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| third law of thermodynamics | <chemistry> The entropy of a perfect crystal at 0 K is zero. (09 Jan 1998) |
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| zeroeth law of thermodynamics | <chemistry> Two systems in thermal equilibrium with a third are in thermal equilibrium with each other. (09 Jan 1998) |
| first law of thermodynamics | This law, derived from the principle of conservation of energy, is expressed as E = Q - W, where E is the internal change in energy, Q is the heat the environment transfers into the system, and W is the work the system does. In other words, it means that: The internal energy in a system isolated from other systems remains constant The change in the internal energy of a system that is not isolated is equal to the energy that crosses its boundariesinto or out of other systemsIt can be further extrapolated to mean that despite all the processesgoing on in the universe, the total energy contained in the universeremains constant. (09 Oct 1997) |
| Mendel's second law | Different hereditary factors assort independently when the gametes are formed; traits at linked loci are an exception. Synonym: Mendel's second law. (05 Mar 2000) |
| thermodynamics | The study of energy and energy flow in closed and open systems. (18 Nov 1997) |
| antidepressive agents, second-generation | A structurally and mechanistically diverse group of drugs that are not tricyclics or monoamine oxidase inhibitors. The most clinically important appear to act selectively on serotonergic systems, especially by inhibiting serotonin reuptake. (12 Dec 1998) |
| burns, second degree | Second degree burns look similar to the first degree burns in that it is red and sensation is intact; however, the damage is severe enough to cause blistering of the skin and the pain is usually somewhat more intense. (12 Dec 1998) |
| centimeter-gram-second system | The scientific system of expressing the fundamental physical units of length, mass, and time, and those units derived from them, in centimeters, grams, and seconds; currently being replaced by the International System of Units based on the meter, kilogram, and second. (05 Mar 2000) |
| centimeter-gram-second unit | <unit> An absolute unit of the centimeter-gram-second system. (05 Mar 2000) |
| meter-kilogram-second system | An absolute system based on the meter, kilogram, and second; the basis of the International System of Units. (05 Mar 2000) |
| meter-kilogram-second unit | An absolute unit of the meter-kilogram-second system. (05 Mar 2000) |
| cycles per second | The number of successive compressions and rarefactions per second of a sound wave. The preferred designation for this unit of frequency is hertz. Acronym: cps (05 Mar 2000) |
| pregnancy trimester, second | Period of pregnancy from the beginning of the 15th through the 28th completed week (99 to 196 days) of gestation. (12 Dec 1998) |
| healing by second intention | Delayed closure of two granulating surfaces. Synonym: secondary adhesion, secondary union. (05 Mar 2000) |
| Scanzoni's second os | A constriction located at the junction of the thinned lower uterine segment with the thick retracted upper uterine segment, resulting from obstructed labour; this is one of the classic signs of threatened rupture of the uterus. Synonym: Bandl's ring, Baudelocque's uterine circle, Scanzoni's second os. (05 Mar 2000) |