The relation between macroscopic irreversibility and microscopic reversibility is a present unsolved problem. Constructal law is introduced to develop analytically the Einstein's, Schrödinger's, and Gibbs' considerations on the interaction between particles and thermal radiation (photons). The result leads to consider the atoms and molecules as open systems in continuous interaction with flows ...

This paper addresses entropy generation in the flow of an electrically-conducting couple stress nanofluid through a vertical porous channel subjected to constant heat flux. By using the Buongiorno model, equations for momentum, energy, and nanofluid concentration are modelled, solved using homotopy analysis and furthermore, solved numerically. The variations of significant fluid parameters with...

Magnetization measurements on Y0.47Pr0.53Ba2Cu3O7 single crystal in the vicinity of the superconducting transition temperature Tc = 7 K revealed a reentrant irreversibility for applied magnetic fields higher than the irreversibility field Hirr. The transition to the second hysteresis loop occurs through an irreversible jump in magnetization. The temperature range of this irreversibility extends...

in this paper, first a sensitivity analysis of parameters affecting the performance of the steam generator is performed. this process includes the pinch temperature difference and the gas velocity (width of the hrsg) as the operating parameter and geometrical parameters (fin’s thickness, fin’s height, number of fins in each inch, tube transverse pitch) for each pressure parts is carried out, an...

There is a growing concern about the feasibility of new generation internal combustion engines in low-temperature and efficient way that can meet emission regulations while maintaining desirable power performance. This requires controllability flexibility over ignition reactivity within cylinder by handling two fuels with different chemical reaction intensity. In this research, controlled compr...

development projects in natural water resources like rivers and lakes, specially transferring water to use in agriculture, domestic and industrial sector without considering environmental values, causes irrecoverable and irreversible damage to ecosystem and future options. if we consider the future generation and species rights, those damages and costs can be very much than we take in. the abov...