Universal Reversible Cycles

Thermodynamic cycles have been generalized. The fundamental equation can be integrated and can be used to derive an expression characterizing the efficiency of a system for any kind of cyclic process by which work is produced [1]. 

As characteristic for thermodynamic cycles, the working system accesses two reservoirs with a low and a high thermodynamic potential. The thermodynamic potentials, i.e., temperature, chemical potential, hydrostatic pressure, electric potential, etc., show an absolute zero of the lower reservoir, when the efficiency of the cycle r] = 1. 

Ginzburg, B.Z., Aharon, 1. The second law of thermodynamics revisited 1. The absolute zero of potential and the general expression for the efficiency of universal reversible cycle. Physica A 210(3-4), 489 95 (1994) 

---

The result that a spontaneous (and therefore irreversible) process occurs with an overall increase of entropy in the system and its surroundings is universally true. The proof of this is based on the fact that the efficiency of a Carnot cycle in which some of the steps are irreversible must be less than that of a purely reversible cycle, since the maximum work is performed by systems which are undergoing reversible processes. Thus in place of equation (5.23) we have, for an irreversible cycle,... 

Because the gas in the Carnot cycle starts and ends at the same state, the system s entropy does not change during a cycle. Now apply the second law to the universe for the case of the Carnot cycle. Because the processes are reversible, the entropy of the universe does not change by Equation 2b. This can be written ... 

The dryer unit has an air inlet, an air outlet, a waste air outlet, two heater coils, and two 4-way reversing valves. Although the illustration shows the two tanks in a functioning mode, they are universal in operation. By this, we mean that this changes the tanks over when the active tank becomes totally saturated, and the tank that was on the regeneration cycle then becomes the active unit. 

During cyclic voltammetry, the potential is similarly ramped from an initial potential E but, at the end of its linear sweep, the direction of the potential scan is reversed, usually stopping at the initial potential E (or it may commence an additional cycle). The potential at which the reverse occurs is known as the switch potential ( >.) Almost universally, the scan rate between E and Ex is the same as that between Ex and E. Values of the scan rates Vforwani and Ubackward are always written as positive numbers. 

Universal recognition sequences must be present in PCR products that are cycle sequenced with universal primers. Many laboratories routinely use universal M13 and M13 reverse tails for their forward and reverse PCR primers, respectively. We have opted for the M13 (but not M13 reverse) sequence in conjunction with a PI72 sequence derived from the Bluescript SK vector. The choice of universal primers was influenced by their estimated free energy of annealing and their melting temperature... 

Reactions of this kind are called substrate-level phosphorylations, as opposed to the protonmotive force-dependent carrier-level phosphorylations mentioned earlier. Substrate-level phosphorylations are involved in only a few processes but these belong to the most central metabolic systems, the glycolytic chain and the Krebs cycle, making substrate-level phosphorylations both universal and indispensable. In addition, the reactions are readily reversible (especially with aldehydes as substrates). They can serve in the reduction of a carboxyl group (—COOH) to a carbonyl group (=CO) with the help of energy provided by the splitting of ATP. As we will see, this process is of key importance in biosynthetic reductions. 

Rem. 16, the Second law (1.18) forbids for (infinite dimensional vector of) heat distribution of cyclic processes (or its densities) the region with absorbed heat only (q > 0,q =0). Moreover, using closeness and completeness of universe Ul, U2 with Carnot cycles, the heat distributions (or their densities) must fall into halfspace which does not meet the forbidden region (with corresponding boundary hyperplane of reversible cyclic processes). This may be similarly expressed through positive function /(H) > 0 of empirical temperature d by... 

The samples were evaluated with the differential rheometer in the following manner Samples of SE-30 and the material of interest were weighed to 0.3 0.0005 g. For each experimental run the samples were loaded into the sample gaps and the control system activated at the initial sample thickness. The loading of the samples invariably introduced an initial deflection in the load cell blade. The samples were therefore allowed to relax until the blade had returned to the zero position (2-3 min). The input waveform from the function generator was then started at the frequency and amplitude of interest. The APPLE-based data collection system was started at the end of 1 cycle and continued for 4-10 cycles at 50-250 points/cycle. After data collection the samples were removed, the pushrods cleaned and fresh samples loaded. The second pair of samples were inserted with the sample sides reversed and data was collected as before. After all runs were completed the pair of data files for each sample set were subtracted point by point to eliminate much of the coherent noise caused by nonuniformity of the two rod motions. The resultant voltage file was transmitted to the University of Connecticut, Department of University Computer Systems IBM 3081. The voltages... 

---