Finite element analysis of materially uniform dielectric elastomers

In this work, we have considered a non-canonical scalar field dark energy model in the framework of flat FRW background. It has also been assumed that the dark matter sector interacts with the non-canonical dark energy sector through some interaction term. Using the solutions for this interacting non-canonical scalar field dark energy model, we have investigated the validity of generalized second law (GSL) of thermodynamics in various scenarios using first law and area law of thermodynamics. For this purpose, we have assumed two types of horizons viz apparent horizon and event horizon for the universe and using first law of thermodynamics, we have examined the validity of GSL on both apparent and event horizons. Next, we have considered two types of entropy-corrections on apparent and event horizons. Using the modified area law, we have examined the validity of GSL of thermodynamics on apparent and event horizons under some restrictions of model parameters.

In the work reported in this paper, we have analyzed generalized Chaplygin gas (GCG) and modified generalized Chaplygin gas (MGCG) in an interacting scenario. The equation of state parameter has been analyzed in both the cases and the stability of the models has been discerned through squared speed of sound. Stability against gravitational perturbations has been observed for both GCG and MGCG interacting with pressureless dark matter. Also, the generalized second law (GSL) of thermodynamics has been tested for different enveloping horizons and validity of GSL has been observed throughout. Furthermore, f(T) gravity has been reconstructed with GCG and MGCG and phantom behaviour has been observed through reconstructed EoS parameters. The squared speed of sound has been derived for f(T) gravity and stability of the model has been established through its positivity.

Fluctuation theorems and the second law of thermodynamics are powerful relations constraining the behavior of out-of-equilibrium systems. While there exist generalizations of these relations to feedback controlled quantum systems, their applicability is limited, in particular when considering strong and continuous measurements. In this Letter, we overcome this shortcoming by deriving a novel fluctuation theorem, and the associated second law of information thermodynamics, which remain applicable in arbitrary feedback control scenarios. In our second law, the entropy production is bounded by the coarse-grained entropy production that is inferrable from the measurement outcomes, an experimentally accessible quantity that does not diverge even under strong continuous measurements. We illustrate our results by a qubit undergoing discrete and continuous measurement, where our approach provides a useful bound on the entropy production for all measurement strengths.

We provide a short review of the recent developments in entropic cosmology based on two thermodynamic laws of the apparent horizon, namely the first and the second laws of thermodynamics. The first law essentially provides the change in entropy of the apparent horizon during the cosmic evolution of the universe; in particular, it is expressed by TdS=−d(ρV)+WdV (where W is the work density and other quantities have their usual meanings). In this way, the first law actually links various theories of gravity with the entropy of the apparent horizon. This leads to a natural question—“What is the form of the horizon entropy corresponding to a general modified theory of gravity?”. The second law of horizon thermodynamics states that the change in total entropy (the sum of horizon entropy + matter fields’ entropy) with respect to cosmic time must be positive, where the matter fields behave like an open system characterised by a non-zero chemical potential. The second law of horizon thermodynamics importantly provides model-independent constraints on entropic parameters. Finally, we discuss the standpoint of entropic cosmology on inflation (or bounce), reheating and primordial gravitational waves from the perspective of a generalised entropy function.

There are two primary laws including the first and second laws of thermodynamics that should be used to assess a process. Generally, only the first law of thermodynamics is investigated in numerical solutions, so it is possible to exist some numerical results that do not satisfy the second law of thermodynamics because of numerical errors. To achieve reliable numerical outcomes, it is better to apply two indexes of HEAT BALANCE ERROR and VIRTUAL ENTROPY GENERATION, which come from the second law of thermodynamics. In other words, an approach to develop computational fluid dynamics investigations is to take second law of thermodynamics into consideration. In this study, two different models including counterflow double‐pipe heat exchanger and single‐pipe with constant wall temperature are simulated in various cases with different efficiencies and temperature ratios. It is found that 46 cases of total 523 double‐pipe models and 24 cases of total 402 simulations of single‐pipe models had unacceptable results regarding to two mentioned criteria. The results revealed that it is less likely to gain unreliable results in smaller efficiency and lower inlet temperature for double‐pipe heat exchanger and single‐pipe respectively.

In this paper, the second law of thermodynamics in the public basic course college physics was taken as an example to achieve the heuristic teaching design with students as the main body. The logical framework of knowledge was reconstructed based on combing knowledge points. This lesson takes the directionality of natural process as the main line, and connects the written expression and mathematical representation of the second law of thermodynamics from macro and micro perspectives, enables students to understand and grasp the essence of the second law of thermodynamics and entropy, and establish the logical connection between the two. At the same time, this lesson integrates current hot topics, organizes ideological and political elements, advances from knowledge to thought layer by layer, and carries out closed-loop teaching that integrates scientific knowledge and humanistic literacy, theoretical learning and practical cognition, achieving the teaching goal of imparting knowledge and educating people, and providing more ideas and references for the teaching design of college physics course under the background of ideological and political education.

This paper presents ordered rate constitutive theories in Lagrangian description for compressible as well as incompressible homogeneous, isotropic thermoviscoelastic solid matter with memory in which the material derivative of order m of the deviatoric stress tensor and heat vector are functions of temperature, temperature gradient, time derivatives of the conjugate strain tensor up to any desired order n, and the material derivatives of up to order m−1 of the stress tensor. The thermoviscoelastic solids described by these theories are called ordered thermoviscoelastic solids with memory due to the fact that the constitutive theories are dependent on orders m and n of the material derivatives of the conjugate stress and strain tensors. The highest orders of the material derivative of the conjugate stress and strain tensors define the order of the thermoviscoelastic solid. The constitutive theories derived here show that the material for which these theories are applicable have fading memory. As is well known, the second law of thermodynamics must form the basis for deriving constitutive theories for all deforming matter (to ensure thermodynamic equilibrium during evolution), since the other conservation and balance laws are independent of the constitution of the matter. The entropy inequality expressed in terms of Helmholtz free energy density \({\Phi}\) does not provide a mechanism to derive a constitutive theory for the stress tensor when its argument tensors are stress and strain rates in addition to others. With the decomposition of the stress tensor into equilibrium and deviatoric stress tensors, the constitutive theory for the equilibrium stress tensor is deterministic from the entropy inequality. However, for the deviatoric stress tensor, the entropy inequality requires a set of inequalities to be satisfied but does not provide a mechanism for deriving a constitutive theory. In the present work, we utilize the theory of generators and invariants to derive rate constitutive theories for thermoviscoelastic solids with memory. This is based on axioms and principles of continuum mechanics. However, we keep in mind that these constitutive theories must satisfy the inequalities resulting from the second law of thermodynamics. The constitutive theories for heat vector q are derived: (i) strictly using conditions resulting from the entropy inequality; (ii) using the theory of generators and invariants with admissible argument tensors that are consistent with the stress tensor as well as the theories in which simplifying assumptions are employed which yield much simplified theories. It is shown that the rate theories presented here describe thermoviscoelastic solids with memory. Mechanisms of dissipation and memory are demonstrated and discussed, and the derivation of memory modulus is presented. It is shown that simplified forms of the general theories presented here result in constitutive models that may resemble currently used constitutive models but are not the same. The work presented here is not to be viewed as extension of the current constitutive models; rather, it is a general framework for rate constitutive theories for thermoviscoelastic solids with memory based on the physics and derivations that are consistent within the framework of continuum mechanics and thermodynamics. The purpose of the simplified theories presented in the paper is to illustrate possible simplest theories within the consistent framework presented here.

The science of thermodynamics is built primarily on two fundamentally natural laws, known as the first and second laws. The first law of thermodynamics is simply an expression of the conservation of energy principle. It asserts that energy is a thermodynamic property, and that during an interaction, energy can change from one form to another but the total amount of energy remains constant. The second law of thermodynamics asserts that energy has quality as well as quantity, and actual processes occur in the direction of decreasing quality of energy. The attempts to quantify the quality or “work potential” of energy in light of the second law of thermodynamics has resulted in the definition of the property named exergy. In this chapter, basic relations for the first and second laws of thermodynamics are provided for closed systems and control volumes. The concepts of entropy and exergy derived from the second law are thoroughly discussed.KeywordsEntropy ChangeEntropy GenerationHeat EngineExergy AnalysisExergy EfficiencyThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

The second law of thermodynamics has been proven by many facts in classicalworld. Is there any new property of it in quantum world? In this paper, wecalculate the change of entropy in T.D. Kieu's model for quantum heat engine(QHE) and prove the broad validity of the second law of thermodynamics. Itis shown that the entropy of the quantum heat engine neither decreases in awhole cycle, nor decreases in either stage of the cycle. The second law ofthermodynamics still holds in this QHE model. Moreover, although themodified quantum heat engine is capable of extracting more work, itsefficiency does not improve at all. It is neither beyond the efficiencyof T.D. Kieu's initial model, nor greater than the reversible Carnot efficiency.

Two fundamental questions are still open about the complex relation between fluid dynamics and thermodynamics. Is it possible (and convenient) to describe fluid dynamic in terms of second law based thermodynamic equations? Is it possible to solve and manage fluid dynamics problems by mean of second law of thermodynamics? This chapter analyses the problem of the relationships between the laws of fluid dynamics and thermodynamics in both first and second law of thermodynamics in the light of constructal law. In particular, taking into account constructal law and the diffusive formulation of Bejan number, it defines a preliminary step through an extensive thermodynamic vision of fluid dynamic phenomena.

The second law of thermodynamics demands, among other things, that in an isolated system heat does not flow from a compartment at low to a compartment at high temperature. Maxwell (1871) pointed out that a “being” that could deal with individual molecules, when positioned at a trap door between two compartments at different temperatures, might open the door whenever a molecule with much higher than average kinetic energy would approach from the cold compartment, and whenever a kinetically “cold” molecule would approach from the “hot” compartment (see also Brush, 1976). Consequently, such a “Maxwell’s demon” would cause heat to flow from the cold to the hot compartment and violate the second law. For quite some time, the validity of the second law of thermodynamics seemed to depend on the absence of Maxwellian demons from the systems under consideration. Also, it was deemed plausible that the special property long sought for living systems, was nothing but the presence of Maxwellian demons within than. Whilst Maxwell already argued that beings, other than supernatural, would lack the knowledge about the positions and velocities of the molecules, Szilard (1929), Demers (1945) and Brillouin (1956) have since resolved this paradox: the demon would require a continuous influx of information, which should be counted as a kind of work-input and would violate the required isolation of the system. In fact, the collection of this information would always cost more than could be obtained by having the displaced heat drive an engine. Thus, the second law of thermodynamics does apply to all physical chemical systems, living and inanimate alike. Whenever an apparent (or, even, potentially real) violation of the second law of thermodynamics arises, one may indicate this by invoking a Maxwellian demon.

In a vivid statement that has become part of physics’ folklore, Eddington expressed an almostmystical view of the second law [1]:The law that entropy always increases – the second law of thermodynamics – holds, Ithink, the supreme position among the laws of nature. If someone points out that your pettheory of the universe is in disagreement with Maxwell’s equations – then so much theworse for Maxwell’s equations. If it is found to be contradicted by experiments – well,these experimentalists do bungle things sometimes. But if your theory is found to beagainst the second law of thermodynamics I can give you no hope; there is nothing for itbut to collapse in deepest humiliation (p. 74).For Jaynes [2], however, entropy was nothing butAn anthropomorphic concept, not only in the well-known statistical sense that itmeasures the extent of human ignorance as to the micro-state.

Tendon driven actuators are getting mature in electroactive polymer (EAP) researches. Research and development of the dielectric elastomer (DE) actuator from EAP family, have produced significant progress for decades. Dielectric elastomer is used in this paper to model a micro actuator platform. The parallel platform designing in this paper consists of the kinematics of the platform that is suited for micro structure of the robotic link. This may use for redundant manipulator or snake robot structure. DE is silicon artificial muscles that will actuated by applying voltage which perform a great actuation due to its linear large deflection. A remarkable amount of work has focused on delivering the feasibility of the robotic application of DE material. However, few commercial products equipped with polymer actuators have been introduced in the market, probably because most of the research has been dedicated either to discovering new actuation properties of the polymeric material. Therefore, this polymer is used to model the tendon driven parallel platform actuator for robotic application in this research. In this actuator design, both the upper and lower platforms are of configurations of equilateral triangles with DE cables attached close to the vertices. One DE cable attaches each of the vertices of the lower platform to the vertices directly above it on the upper platform. The three tendons thus enable the platform to exhibit 3 degrees of freedom (DOF). The dielectric polymers are attached with the three edges of the platforms that act like compression-tension cable because of their linear deformation characteristics. Therefore the platform of the DE actuator model is achieved in this research. This actuator can be used to develop redundant robot like snake robot or elephant trunk robot.

A recently proposed quantum mechanical criterion `concavity of energy' for the second law of thermodynamics is studied also for classical particle systems confined in a bounded region by a potential with a time-dependent coupling constant. It is shown that the time average of work done by particles in a quench process cannot exceed that in the corresponding quasi-static process, if the energy is a concave function of the coupling constant. It is proven that the energy is indeed concave for a general confining potential with certain properties. This result implies that the system satisfies the principle of maximum work in the adiabatic environment as an expression of the second law of thermodynamics.

One out of many emerging implications from solutions of Einstein's general relativity equations are closed timelike curves (CTCs), which are trajectories through spacetime that allow for time travel to the past without exceeding the speed of light. Two main quantum models of computation with the use of CTCs were introduced by Deutsch (D-CTC) and by Bennett and Schumacher (P-CTC). Unlike the classical theory in which CTCs lead to logical paradoxes, the quantum D-CTC model provides a solution that is logically consistent due to the self-consistency condition imposed on the evolving system, whereas the quantum P-CTC model chooses such solution through post-selection. Both models are non-equivalent and imply nonstandard phenomena in the field of quantum computation and quantum mechanics. In this work we study the implications of these two models on the second law of thermodynamics - the fundamental principle which states that in an isolated system the entropy never decreases. In particular, we construct CTC-based quantum circuits which lead to decrease of entropy.