scholarly journals THERMODYNAMICS OF FRIEDMANN EQUATION AND MASSLIKE FUNCTION IN GENERAL BRANEWORLD

2009 ◽  
Vol 24 (31) ◽  
pp. 5877-5888 ◽  
Author(s):  
TAO ZHU ◽  
JI-RONG REN ◽  
SHU-FAN MO
Keyword(s):  
Apparent Horizon ◽  
Friedmann Equation ◽  
Curvature Correction ◽  
First Law Of Thermodynamics ◽  
New Type ◽  
Braneworld Model ◽  
The Difference ◽  
Correction Terms

Using the generalized procedure proposed by S. F. Wu et al.23 recently, we construct the first law of thermodynamics on apparent horizon in a general braneworld model with curvature correction terms on the brane and in the bulk, respectively. The explicit entropy formular of apparent horizon in the general braneworld is worked out. We also discuss the masslike function which associated with a new type first law of thermodynamics of the general braneworld in detail. We analyze the difference between the conventional thermodynamics and the new type thermodynamics on apparent horizon. At last, the discussions about the physical meanings of the masslike function have also been given.

scholarly journals EQUIPARTITION OF ENERGY AND THE FIRST LAW OF THERMODYNAMICS AT THE APPARENT HORIZON

2011 ◽  
Vol 20 (04) ◽  
pp. 553-559 ◽  
Author(s):  
FU-WEN SHU ◽  
YUNGUI GONG
Keyword(s):  
Apparent Horizon ◽  
Friedmann Equation ◽  
Consistency Check ◽  
First Law Of Thermodynamics ◽  
A Value ◽  
Cosmological Observations ◽  
Equipartition Law ◽  
Equipartition Of Energy ◽  
The Universe ◽  
Friedmann Robertson Walker

We apply the holographic principle and the equipartition law of energy to the apparent horizon of a Friedmann–Robertson–Walker universe and derive the Friedmann equation describing the dynamics of the universe. We also show that the equipartition law of energy can be interpreted as the first law of thermodynamics at the apparent horizon. The consistency check shows that our derivation is correct for –1 < w < –(1/3), a value that matches the recent cosmological observations.

Cosmological Friedmann equation in infrared modified Hořava–Lifshitz gravity via generalized Misner–Sharp mass

2016 ◽  
Vol 31 (23) ◽  
pp. 1650123 ◽  
Author(s):  
Molin Liu ◽  
Yuling Yang ◽  
Yu Han ◽  
Zonghua Zhao ◽  
Jianbo Lu
Keyword(s):  
Field Equation ◽  
Apparent Horizon ◽  
Friedmann Equation ◽  
Gravitational Action ◽  
First Law Of Thermodynamics ◽  
Friedmann Equations ◽  
Gravity Theories ◽  
Friedmann Robertson Walker

In various gravity theories, Friedmann equations can be cast to a form of the first law of thermodynamics in a Friedmann–Robertson–Walker (FRW) cosmological setup. However, this result failed in recent infrared (IR) modified Hořava–Lifshitz (HL) gravity. The difficulty stems from the fact that HL gravity is Lorentz-violating. Motivated by this problem, we use the Misner–Sharp mass to investigate the thermodynamics near the apparent horizon in HL cosmology. We find that the Friedmann equations can be derived from the first law of thermodynamics. The Misner–Sharp mass used here inherits the specific properties of HL gravity since it is directly from the gravitational action of HL theory. We also prove that the first law of thermodynamics with logarithmic entropy still holds at the apparent horizon in FRW. The results suggest that the general prescription of deriving the field equation from thermodynamics still works in the HL cosmology.

scholarly journals THERMODYNAMICS OF VISCOUS DARK ENERGY IN AN RSII BRANEWORLD

2010 ◽  
Vol 19 (02) ◽  
pp. 171-181 ◽  
Author(s):  
M. R. SETARE ◽  
A. SHEYKHI
Keyword(s):  
Dark Energy ◽  
Apparent Horizon ◽  
Friedmann Equation ◽  
Second Law Of Thermodynamics ◽  
Point Of View ◽  
Accelerating Universe ◽  
Spatial Curvature ◽  
First Law Of Thermodynamics ◽  
Generalized Second Law ◽  
Physical Boundary

We show that for an RSII braneworld filled with interacting viscous dark energy and dark matter, one can always rewrite the Friedmann equation in the form of the first law of thermodynamics, dE = ThdSh + WdV, at the apparent horizon. In addition, the generalized second law of thermodynamics can be fulfilled in a region enclosed by the apparent horizon on the brane for both constant and time-variable five-dimensional Newton's constant G5. These results hold regardless of the specific form of the dark energy. Our study further supports the belief that in an accelerating universe with spatial curvature, the apparent horizon is a physical boundary from the thermodynamical point of view.

Dynamic Characteristic Analysis of New Pneumatic Bending Joint

2012 ◽  
Vol 271-272 ◽  
pp. 1742-1749
Author(s):  
Peng Cheng Huang ◽  
Qing Hua Yang ◽  
Guan Jun Bao ◽  
Li Bin Zhang
Keyword(s):  
Response Time ◽  
Dynamic Characteristic ◽  
Simulation Analysis ◽  
Characteristic Analysis ◽  
Pneumatic Actuators ◽  
Bending Performance ◽  
First Law Of Thermodynamics ◽  
Existing Problems ◽  
Joint Damping ◽  
New Type

Aimed at existing problems on the bending performance of pneumatic bending joint, a new type of pneumatic bending joint is proposed in this paper. Double flexible pneumatic actuators are used as actuating drivers. Based on the first law of thermodynamics and the joint dynamic equation, the angle dynamic model is established and analyzed. Moreover simplified model is proposed. Meanwhile, its dynamic characteristic is analyzed through simulation analysis. The simulation suggests the following results: in the gas-filled phase, the joint’s pressure response time is about 10ms; while it is about 60ms in the gas-escape phase; and the angle response time of joint is 10 to 20ms. When the joint damping coefficient is increasing, this value will also increase.

New analysis of holophotoelastic patterns and their application

1976 ◽  
Vol 11 (1) ◽  
pp. 11-17 ◽  
Author(s):  
J Ebbeni ◽  
J Coenen ◽  
A Hermanne
Keyword(s):  
Numerical Methods ◽  
Dynamic Problems ◽  
Principal Stresses ◽  
Optical Elements ◽  
New Type ◽  
The Difference ◽  
Fringe Patterns

This paper shows that by the use of a new type of diffuser it is possible in photo-holoelasticimetry, without any addition of optical elements or particular preparation of the specimen, to record simultaneously but separately fringe patterns respectively related to the sum and the difference of the principal stresses. The value of intensity of the interfering light reaching the hologram plate is established and hence the equations of the recorded pseudoisopachic fringe patterns are given. Used successfully for the study of particular static problems, where numerical methods are very difficult or impossible, the present interferometer is also suited for dynamic problems.

scholarly journals Research Status and Development Trend of Magnetic Fluid Acceleration Sensors

2021 ◽  
pp. 10-15
Author(s):  
Mu Xueyu ◽  
Yang Shaojie ◽  
Kong Xiangdong
Keyword(s):  
General Structure ◽  
Inertial Mass ◽  
Development Trend ◽  
Research Progress ◽  
Acceleration Sensor ◽  
Magnetic Liquid ◽  
Existing Problems ◽  
Acceleration Sensors ◽  
New Type ◽  
The Difference

As a new type of accelerometer, in recent years, the magnetic liquid acceleration sensor has attracted widespread attention worldwide, and related research results have also continued to emerge. This article mainly introduces the theoretical basis and general structure of the magnetic liquid acceleration sensor, and according to the difference of inertial mass, briefly describes the research progress of the magnetic liquid acceleration sensor by national and foreign scholars in recent years and some in existing problems. Finally, suggestions and prospects for the future development trend of the magnetic liquid acceleration sensor are given.

scholarly journals Ideological Phantoms of Civilisation and Culture: Identity and Tolerance

2019 ◽  
pp. 1-13
Author(s):  
Natalia Yu. Beregovaya ◽  
Olga A. Karlova
Keyword(s):  
Community Based ◽  
Culture Studies ◽  
Historical Method ◽  
Philosophical Aspect ◽  
New Type ◽  
The Subject ◽  
The Difference ◽  
Ideological Manipulation ◽  
Global World ◽  
Modelling Methods

The article considers the philosophical aspect of defining the immanence and attribution of the concept of “tolerance” to the culture itself. The subject of the research is especially relevant due to the modern processes that are happening in the global world, and the difference in key methodological positions of modern Russian and Western science on this issue today. The purpose of this study is to clarify the philosophical basis of the existing opposition of societies with traditional ethical cultures (Russia, China) and the ‘new-type’ poly-state European ethnic community. Based on the analysis of current social processes in Russia and Europe using the comparative historical method, modelling methods and model extrapolation in the field of culture studies, social psychology and political science, the article identifies the main approaches to ethnic and social identity, their cultural and ideological components. The authors prove the hypothesis that culture requires designation of its border with another culture, recognition of this border, which distinguishes and confirms cultural semantics. Denial of this fact is a method of ideological manipulation of the ethno-social consciousness of society in the framework of globalisation processes

scholarly journals An effective cosmological constant from an entropic formulation of gravity

2020 ◽  
Vol 29 (09) ◽  
pp. 2050064
Author(s):  
I. Díaz-Saldaña ◽  
J. C. López-Domínguez ◽  
M. Sabido
Keyword(s):  
Cosmological Constant ◽  
Apparent Horizon ◽  
Friedmann Equation ◽  
Scale Factor ◽  
Late Time ◽  
Frw Universe ◽  
Equation Solving ◽  
Effective Cosmological Constant ◽  
Time Regime ◽  
Modified Entropy

In this work, we study a Friedmann–Robertson–Walker (FRW) universe derived from a modified entropy–area relationship. By applying the first law of thermodynamics to the so-called apparent horizon and a modified entropy–area relationship, we obtain a modified Friedmann equation. Solving this model for a perfect fluid with vanishing cosmological constant, we find that for early times, the scale factor is the same as that of an FRW universe. In the late-time regime, although the cosmological constant is zero, the asymptotic behavior of the scale factor is exponential, and therefore, we can identify an effective cosmological constant. The origin of the effective cosmological constant can be traced to the modifications of the entropy–area relation.

Difference Synchronization of Identical and Nonidentical Chaotic and Hyperchaotic Systems of Different Orders Using Active Backstepping Design

2018 ◽  
Vol 13 (5) ◽  
Author(s):  
Eric Donald Dongmo ◽  
Kayode Stephen Ojo ◽  
Paul Woafo ◽  
Abdulahi Ndzi Njah
Keyword(s):  
Chaotic System ◽  
Initial Conditions ◽  
Lyapunov Stability Theory ◽  
The State ◽  
State Variables ◽  
State Variable ◽  
New Type ◽  
The Difference ◽  
Synchronization Scheme ◽  
Hyperchaotic Systems

This paper introduces a new type of synchronization scheme, referred to as difference synchronization scheme, wherein the difference between the state variables of two master [slave] systems synchronizes with the state variable of a single slave [master] system. Using the Lyapunov stability theory and the active backstepping technique, controllers are derived to achieve the difference synchronization of three identical hyperchaotic Liu systems evolving from different initial conditions, as well as the difference synchronization of three nonidentical systems of different orders, comprising the 3D Lorenz chaotic system, 3D Chen chaotic system, and the 4D hyperchaotic Liu system. Numerical simulations are presented to demonstrate the validity and feasibility of the theoretical analysis. The development of difference synchronization scheme has increases the number of existing chaos synchronization scheme.

The wormhole thermodynamics in f (R ) gravity

2019 ◽  
Vol 35 (04) ◽  
pp. 1950360 ◽  
Author(s):  
A. S. Sefiedgar ◽  
M. Mirzazadeh
Keyword(s):  
Continuity Equation ◽  
Energy Momentum Tensor ◽  
Apparent Horizon ◽  
Second Law Of Thermodynamics ◽  
Momentum Tensor ◽  
Second Law ◽  
Standard Entropy ◽  
Field Equations ◽  
First Law Of Thermodynamics ◽  
Generalized Second Law

Thermodynamics of the evolving Lorentzian wormhole at the apparent horizon is investigated in [Formula: see text] gravity. Redefining the energy density and the pressure, the continuity equation is satisfied and the field equations in [Formula: see text] gravity reduce to the ones in general relativity. However, the energy–momentum tensor includes all the corrections from [Formula: see text] gravity. Therefore, one can apply the standard entropy-area relation within [Formula: see text] gravity. It is shown that there may be an equivalency between the field equations and the first law of thermodynamics. It seems that an equilibrium thermodynamics may be held on the apparent horizon. The validity of the generalized second law of thermodynamics (GSL) is also investigated in the wormholes.

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