Another impossible engine

The efficiency, 6, of a heat engine is defined as the ratio of the work produced to the quantity of heat extracted from the high-temperature reservoir  

Since and Q2 differ in sign, the second term in Eq. (8.6) is negative consequently, the efficiency is less than unity. The efficiency is the fraction of the heat withdrawn from the high-temperature reservoir that is converted into work in the cyclic process. 

Suppose that we run engine E in its reverse cycle and couple it to engine E running in its forward cycle. This gives us a composite cyclic engine that produces heat and work effects that are simply the sum of the individual effects of the appropriate cycles  

By making the engine the proper size, matters are arranged so that the composite engine produces no work effect in the surroundings that is, we adjust until -W + W = 0, or 

We now examine these heat effects in the reservoirs under the assumption that the efficiency of E is greater than that of E, that is. 

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The theory behind the third law of thermodynamics was initially formulated by Walther Nemst in 1906, which was known as Nemst theorem (https //www.sussex. ac.uk/webteam/gateway/file.php name=a-thermodynamicshistory. pdf site=35). The third law of thermodynamics was conceived from the fact that attaining absolute zero temperature is practically impossible. Lord Kelvin deduced this fact from the second law of thermodynamics with his study of heat transfer, work done, and efficiency of a number of heat engines in series. Kelvin s work was the foundation for the formulation of the third law. It can be stated as follows Absolute zero temperature is not attainable in thermodynamic processes. Another noted scientist, Max Planck, put forward the third law of thermodynamics from his observations in 1913. It states that The entropy of a pure substance is zero at absolute zero temperature. Plank observed that only pure, perfectly crystalline stmctures would have zero entropy at absolute zero temperamre. All other substances attain a state of minimum energy at absolute zero temperature as the molecules of the substance are arranged in their lowest possible energy state. 

The problems may also stem from unhandled controlled-system states and environmental conditions. An F-18 was lost when a mechanical failure in the aircraft led to the inputs arriving faster than expected, which overwhelmed the software [70]. Another F-18 loss resulted from the aircraft getting into an attitude that the engineers had assumed was impossible and that the software was not programmed to handle. 

Apart from gaining an insight into intermolecular forces, theoretical studies have another important and practical use and that is predicting activity coefficients. Especially in the chemical engineering and possibly analytical fields such predictions are most useful. The accuracy of prediction varies from one class of compounds to another. For example, in the case of n-alkane mixtures by use of the segment theory combined with the configurational contribution theory, the prediction is better than 1 per cent. On the other hand, it is impossible to predict activity coefficients for systems involving surface adsorption. 

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