Влияние режима старения в мартенситном состоянии под сжимающей нагрузкой на двусторонний эффект памяти формы в монокристаллах ферромагнитного сплава Ni-=SUB=-49-=/SUB=-Fe-=SUB=-18-=/SUB=-Ga-=SUB=-27-=/SUB=-Co-=SUB=-6-=/SUB=-

The effects of stress-induced martensite aging (SIM-aging) along the [110]B2-direction on the thermoelastic martensitic transformation in Ni49Fe18Ga27Co6 single crystals were investigated. It was experimentally established that the effective regime of SIM-aging (at T = 423 K, 1 h under a compressive stress 450 MPa) results in a stabilization of stress-induced martensite and inducing the tensile two-way shape memory effect with reversible strain of +9.0 (± 0.3) % along the [001]B2-direction which is the perpendicular to the SIM-aging axis. Maximum work output of Wmax = 0.14 J/g (1125 kJ/m3) that can be realized using the two-way shape memory effect was obtained.

Stochastic Novikov Engine with Fourier Heat Transport

The Stochastic Novikov engine is an endoreversible model for heat engines where the heat supply takes place at a fluctuating temperature. These fluctuations can be observed for example at solar thermal power plants. While recently the influence of the temperature fluctuations on the engine’s performance has been studied for Newtonian heat transport, the relation between the used heat transport type and the performance measures remained open. Therefore, we here consider a Stochastic Novikov engine with Fourier heat transport. Based on a short summary of the concept of a Stochastic Novikov engine and the corresponding different control types, the maximum work output and the corresponding efficiency are derived. In particular, we discuss the influence of the distribution’s parameters on the engine’s performance assuming a uniform temperature distribution. We find that the heat transport type has a significant effect on some of the engine’s fundamental properties.

Ecological Performance of a Generalized Radiative System Light-Driven Engine (LDE) With [A] ⇌ [B] Reacting System Improved by Controlling Piston Motion

This paper introduces the ecological criterion (EC) into the optimal configuration problem of an irreversible light-driven engine (LDE) under the assumption that heat transfer (HT) between the working fluid (WF) and the surroundings is presumed to abide by the generalized radiative heat transfer law (HTL) [q ∝ Δ(Tn) ]. The WF is made up of the reacting system [A] ⇌ [B] , and the primary irreversibilities corresponding to the practical engine are the piston friction and heat conduction with the WF operating at a nonzero rate and far from equilibrium. Meantime, in order to obtain the optimal paths (OPs) for maximum ecological performance (EP) of the engine, the optimal control theory (OCT) is utilized in this paper. Numerical calculations of the OPs at maximum EP with linear phenomenological (n = −1), Newton’s (n = 1) and radiative (n = 4) HTLs are performed. The results derived by maximum EP are compared with those derived by maximum work output (WO) and minimum entropy generation (EG) as well as different HTLs. The results obtained in this paper indicate that utilizing the maximum EC as the design objective could effectively accomplish the EG reduction with a little decrease in the WO. Moreover, the OPs for maximum EP with different HTLs are quite different.

Graphene as Cathode Material in Molten Carbon Fuel Cells

The molten carbonate fuel cell (MCFC) is considered one of the best technologies for stationary power. This is due to its high efficiency, medium–high operating temperature, and low emissions. The MCFC operates at a temperature range from 600oC to 700oC and normally is combined with the gas turbine (GT) as a topping cycle. This work investigates the impact of Platinum/Graphene (Pt/G) on a combined cycle of MCFC-GT by applying the first and second laws of thermodynamics. The maximum work output of the hybrid cycle is ultimately calculated to be 1350 kW. The overall exergy efficiency achieved is 59.82%. Our findings reveal that there is an average 23% gain in the maximum work output, energy and exergy efficiencies when Pt/G is used as the cathode material compared to other materials such as Platinum/Carbon (Pt/C) and Platinum/Carbon cloth (Pt/CC).

Maximum work output of multistage continuous Carnot heat engine system with finite reservoirs of thermal capacity and radiation between heat source and working fluid

Optimal temperature profile for maximum work output of multistage continuous Carnot heat engine system with two reservoirs of finite thermal capacity is determined. The heat transfer between heat source and the working fluid obeys radiation law and the heat transfer between heat sink and the working fluid obeys linear law. The solution is obtained by using optimal control theory and pseudo-Newtonian heat transfer model. It is shown that the temperature of driven fluid monotonically decreases with respect to flow velocity and process duration. The maximum work is obtained. The obtained results are compared with those obtained with infinite low temperature heat sink.