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Premium member Presentation Transcript Thermodynamics: Life system: Syllabus: Energy Concepts and Sources: Laws of thermodynamics as applied to energy transfer and transformations: Heat transfer and insulation; Thermodynamics: Life systemPowerPoint Presentation: AimThird principle of energetics : Third principle of energetics As a system approaches absolute zero of temperature all processes cease and the entropy of the system approaches a minimum value or zero for the case of a perfect crystalline substance.Fourth principle of energetics : Fourth principle of energetics There seem to be two opinions on the fourth principle of energetics: The Onsager reciprocal relations are sometimes called the fourth law of thermodynamics. As the fourth law of thermodynamics Onsager reciprocal relations would constitute the fourth principle of energetics. In the field of ecological energetics H.T. Odum considered maximum power, the fourth principle of energetics. Odum also proposed the Maximum empower principle as a corollary of the maximum power principle, and considered it to describe the propensities of evolutionary self-organisation.Fifth principle of energetics : Fifth principle of energetics The energy quality factor increases hierarchically. From studies of ecological food chains, Odum proposed that energy transformations form a hierarchical series measured by Transformity increase ( Odum 2000, p. 246). Flows of energy develop hierarchical webs in which inflowing energies interact and are transformed by work processes into energy forms of higher quality that feedback amplifier actions, helping to maximise the power of the system" — ( Odum 1994, p. 251)Sixth principle of energetics : Sixth principle of energetics Material cycles have hierarchical patterns measured by the energy/mass ratio that determines its zone and pulse frequency in the energy hierarchy. ( Odum 2000, p. 246). M.T. Brown and V. Buranakarn write, "Generally, energy per mass is a good indicator of recycle-ability, where materials with high energy per mass are more recyclable" (2003, p. 1).First Law of Thermodynamics: Description The essence of the First Law of Thermodynamics declares: energy cannot be destroyed. The first law of thermodynamics basically states that an isolated thermodynamic system can store or hold energy and that this internal energy is conserved. Heat is a process by which energy is added to a system from a high-temperature heat source, or lost to a low-temperature heat sink. In addition, energy may be lost by the system when it does mechanical work on its surroundings, or conversely, it may gain energy as a result of work done on it by its surroundings. The first law states that this energy is conserved: The change in the internal energy is equal to the amount added by heating minus the amount lost by doing work on the environment. For a system with a fixed number of particles (a closed system), the first law is usually stated as: where d U is a small increase in the internal energy of the system, δ Q is a small amount of heat added to the system, and δ W is a small amount of work done by the system. As an analogy, if heat were money, then we could say that any change in our savings ( d U ) is equal to the money we put in ( δ Q ) minus the money we spend ( δ W ). First Law of ThermodynamicsPowerPoint Presentation: First law of thermodynamics a generalized expression of the law of the conservation of energy, : the increase in the internal energy of a system is equal to the amount of energy added to the system by heating, minus the amount lost in the form of work done by the system on its surroundings.The second law of thermodynamics, in a concise form, states that "the total entropy of any thermodynamically isolated system tends to increase over time, approaching a maximum value. : The second law of thermodynamics , in a concise form, states that "the total entropy of any thermodynamically isolated system tends to increase over time, approaching a maximum value. General description In a general sense, the second law says The differences between systems in contact with each other tend to even out. Pressure differences, density differences, and particularly temperature differences, all tend to equalize if given the opportunity. This means that an isolated system will eventually come to have a uniform temperature. A thermodynamic engine is an engine that provides useful work from the difference in temperature of two bodies. Since any thermodynamic engine requires such a temperature difference, it follows that no useful work can be derived from an isolated system in equilibrium, there must always be energy fed from the outside.The second law of thermodynamics has been stated in several ways. Succinctly, the second law of thermodynamics can be stated as:: The second law of thermodynamics has been stated in several ways. Succinctly, the second law of thermodynamics can be stated as: It is impossible to obtain a process such that the unique effect is the subtraction of a positive heat from a reservoir and the production of a positive work; A system operating in contact with a thermal reservoir cannot produce positive work in its surroundings (Kelvin); A system operating in a cycle cannot produce a positive heat flow from a colder body to a hotter body ( Clausius ) If thermodynamic work is to be done at a finite rate, free energy must be consumed The entropy of a closed system will not decrease for any sustained period of time (see Maxwell's demon) A downside to this last description is that it requires an understanding of the concept of entropy . There are, however, consequences of the second law that are understandable without a full understanding of entropy. The second law can be described mathematically as: where S is the entropy and the equality sign holds only when the entropy is at its maximum (equilibrium) value. A common misconception is that the second law means that entropy never ever decreases - but the second law is only a tendency, hence, it is only means that it is highly unlikely that entropy will decrease in a closed system at any given instant.Third law of thermodynamics : Third law of thermodynamics It states that: as a system approaches absolute zero of temperature all processes cease and the entropy of the system approaches a minimum value or zero for the case of a perfect crystalline substance. Statements Succinctly, the third law of thermodynamics states: All processes cease as temperature approaches zero; or, As temperature goes to 0, the entropy of a system approaches a constant. Description The third law was developed by Walther Nernst, during the years 1906-1912, and is thus sometimes referred to as Nernst's theorem . The third law of thermodynamics states that the entropy of a system at zero absolute temperature is a well-defined constant. This is because a system at zero temperature exists in its ground state, so that its entropy is determined only by the degeneracy of the ground state; or, it states that " it is impossible by any procedure, no matter how idealised, to reduce any system to the absolute zero of temperature in a finite number of operations ".Zeroth law of thermodynamics : Zeroth law of thermodynamics The term zeroth law was coined by Ralph H. Fowler. In many ways, the law is more fundamental than any of the others. However, the need to state it explicitly as a law was not perceived until the first third of the 20th century, long after the first three laws were already widely in use and named as such, hence the zero numbering. There is still some discussion about its status in relation to the other three laws. The zeroth law of thermodynamics may be succintly stated as: If two thermodynamic systems A and B are in thermal equilibrium, and B and C are also in thermal equilibrium, then A and C are in thermal equilibrium. You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.