Let M = (V, E, A) be a mixed graph with vertex set V , edge set E and arc set A. A cycle cover of M is a family C = {C1, . . . ,Ck} of cycles of M such that each edge/arc of M belongs to at least one cycle in C. The weight of C is ∑k i=1 |Ci |. The minimum cycle cover problem is the following: given a strongly connected mixed graph M without bridges, find a cycle cover of M with weight as small...

  A refrigeration cycle is a chain of various pieces of equipment including compressors, condensers, evaporators, and expansion devices each of which takes on a particular thermodynamic process duty in the cycle that eventually results in the production of the required refrigeration. The results of optimized mixed refrigerant cycles (MRCs) in Part I show that the configuration of MRC is an eff...

natural gas is often associated with nitrogen and heavy compounds. the heavy components in the natural gas not only can feed downstream units, owing to the low temperature process may be formed solid as well. therefore, heavy components separation can be a necessity and produce useful products. virtually, all natural gases are containing nitrogen ​​that would lower the heating value of natural ...

In the paper by Abe and Okuyama [Phys. Rev. E 83, 021121 (2011)], the quantum Carnot cycle of a simple two-state model of a particle confined in a one-dimensional infinite potential well is discussed. It is claimed that the state at the beginning of the quantum Carnot cycle is pure. After that, it is apparently transmuted to a mixed state if Clausius equality is imposed. We prove that this stat...

in this paper, the effects of input temperature and compression ratio on the net output work and efficiency of the air standard cycles, i.e. atkinson cycle, diesel cycle and otto cycle are analyzed. we assumed that the compression and power processes are adiabatic and reversible and any convective, conductive and radiative heat transfer to cylinder wall during the heat rejection process may be ...