A metafluid with multistable density and internal energy states

The efficiency, operation range, and environmental safety of energy and refrigeration cycles are determined by the thermodynamic properties of available fluids. We here suggest combining gas, liquid and multistable elastic capsules to create an artificial fluid with a multitude of stable states. We study, theoretically and experimentally, the suspension’s internal energy, equilibrium pressure-density relations and their stability for both adiabatic and isothermal processes. We show that the elastic multistability of the capsules endows the fluid with multistable thermodynamic properties, including the ability of capturing and storing energy at standard atmospheric conditions, not found in naturally available fluids.

Simulating Finite-Time Isothermal Processes with Superconducting Quantum Circuits

Finite-time isothermal processes are ubiquitous in quantum-heat-engine cycles, yet complicated due to the coexistence of the changing Hamiltonian and the interaction with the thermal bath. Such complexity prevents classical thermodynamic measurements of a performed work. In this paper, the isothermal process is decomposed into piecewise adiabatic and isochoric processes to measure the performed work as the internal energy change in adiabatic processes. The piecewise control scheme allows the direct simulation of the whole process on a universal quantum computer, which provides a new experimental platform to study quantum thermodynamics. We implement the simulation on ibmqx2 to show the 1/τ scaling of the extra work in finite-time isothermal processes.

On the ambiguity of an ideal gas entropy concept

Based on a critical analysis of the existing characteristics of an ideal gas and the theory of thermodynamic potentials, the article considers its new model, which includes the presence of an ideal gas in addition to kinetic energy of potential (chemical) energy, in the framework of which the isothermal and adiabatic processes in it are studied both reversible and irreversible, in terms of changes in the entropy of the system in question, observed in case. In addition, a critical analysis was made of the process of introducing the concept of entropy by R. Clausius, as a result of which the main requirements for entropy were established, the changes of which are observed in isothermal and adiabatic quasistatic processes, in particular, it was revealed that if in isothermal processes involving one in a perfect gas, the entropy ST is uniquely characterized by the value , regardless of whether the process is reversible or not, then when the adiabatic processes occur, the only requirement made of them is the condition of mutual destruction adiabats in this Carnot cycle. As a result of this circumstance, in fact, in thermodynamics various “adiabatic” entropies are used, namely; const SA = const R ln V и C V ln T , and in addition, as established in this paper, CV, which leads, despite the mathematically perfect introduction of the concept of entropy for the Carnot cycle, to the impossibility of its unambiguous interpretation and, therefore, the determination of its physicochemical meaning even for perfect gas. A new concept is introduced in the work: “total” entropy of an ideal gas SS = R ln V + C V , satisfying the criteria of R. Clausius, on the basis of which it was established that this type of entropy multiplied by the absolute temperature characterizes a certain level of potential energy of the system, which can besuccessively converted to work in an isothermal reversible process, with the supply of an appropriate amount of heat, and in the adiabatic reversible process under consideration.

Characterization of Thermomechanical Boundary Conditions of a Martensitic Steel for a FAST Forming Process

The present work characterized and modelled the interfacial heat transfer coefficient and friction coefficient of a non-alloy martensitic steel, for a novel Fast light Alloy Stamping Technology (FAST) process. These models were validated through temperature evolution, thickness distribution and springback measurements on experimentally formed demonstrator components, which were conducted on a pilot production line and showed close agreement, with less than 10% variation from experimental results. The developed models and finite element simulations presented in this work demonstrate that non-isothermal processes can be precisely simulated with implementation of the accurate thermomechanical boundary conditions.

Formation kinetics of Sr0.25Ba0.75Nb2O6 and Li2B4O7 crystals from 0.25SrO–0.75BaO–Nb2O5–Li2O–2B2O3 glass

We have investigated the transition kinetics of Sr0.25Ba0.75Nb2O6 (SBN) and Li2B4O7 (LBO) crystals from 0.25SrO–0.75BaO–Nb2O5–Li2O–2B2O3 (SBNLBO) glass under isothermal and non-isothermal processes.