scholarly journals Equal Area Laws and Latent Heat ford-Dimensional RN-AdS Black Hole

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Li-Chun Zhang ◽  
Hui-Hua Zhao ◽  
Ren Zhao ◽  
Meng-Sen Ma
Keyword(s):  
Black Hole ◽  
Phase Diagrams ◽  
Latent Heat ◽  
Critical Value ◽  
Phase Coexistence ◽  
Thermodynamic Quantities ◽  
Two Phase ◽  
Equal Area ◽  
The Real ◽  
Coexistence Line

We study the equal area laws ofd-dimensional RN-AdS black hole. We choose two kinds of phase diagrams,P-VandT-S. We employ the equal area laws to find an isobar which is the real two-phase coexistence line. Our calculation is much simpler to derive the critical value of the thermodynamic quantities. According to the thermodynamic quantities, we also study the latent heat of the black hole.

Cellular automaton simulations of a four-leg intersection with two-phase signalization

2014 ◽  
Vol 25 (03) ◽  
pp. 1350099 ◽  
Author(s):  
Cheng-Jie Jin ◽  
Wei Wang ◽  
Rui Jiang ◽  
Hao Wang
Keyword(s):  
Cellular Automaton ◽  
Phase Diagrams ◽  
Critical Value ◽  
Signalized Intersection ◽  
Travel Times ◽  
Two Phase ◽  
Flow Rates ◽  
Left Turn

In this paper, we present a cellular automaton (CA) simulation of a signalized intersection. When there is no exclusive lane for left-turn vehicles, through vehicles and left-turn vehicles have to share one lane. Under such situation usually two-phase signalization is adopted, and the conflicts between the two traffic streams need to be analyzed. We use a refined configuration for the intersection simulation: the geometry of the intersection has been considered and vehicles are assumed to move along 1/4 circle arcs. We focus on the averaged travel times on left lanes and their distributions. The diagrams of intersection approach capacities (IACs) and the corresponding phase diagrams are also presented, which depend on the approach flow rates and the percentage of left-turn vehicles. Besides, we find that the minimum green time could be determined by finding out the critical value for the travel times.

PHASE TRANSITION OF THE REISSNER-NORDSTROM BLACK HOLE

2020 ◽  
Vol 65 (6) ◽  
pp. 46-53
Author(s):  
Hoa Le Viet ◽  
Anh Nguyen Tuan ◽  
Hue Dang Thi Minh
Keyword(s):  
Phase Transition ◽  
Black Hole ◽  
Phase Transitions ◽  
Specific Heat ◽  
Gas Phase ◽  
Critical Value ◽  
Thermodynamic Quantities ◽  
Spatial Curvature ◽  
Isobaric Specific Heat ◽  
Analytic Expressions

The phase transition of matter outside the four-dimensional Reissner-Nordstr¨om charged black hole have been investigated. Based on the metric we have found analytic expressions for thermodynamic quantities as temperature, pressure and isobaric specific heat. The numerical results have shown that for temperatures T less than the critical value Tc there exits a ”liquid-gas” phase transition similar to the Van der Waals fluid. In addition, also pointed out that both temperature and spatial curvature affect phase transitions, but phase transitions are always the first oder.

scholarly journals Effects of nicotine on the thermodynamics of the DPPC phase coexistence region

2019 ◽  
Author(s):  
Ernanni D. Vieira ◽  
A. J. Costa-Filho ◽  
Luis. G. M. Basso
Keyword(s):  
Heat Capacity ◽  
Electrostatic Interactions ◽  
Lipid Membrane ◽  
Phase Coexistence ◽  
Thermodynamic Quantities ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Membrane Function ◽  
Non Linear ◽  
Entropically Driven

ABSTRACTPhase separation plays critical roles in several membrane functions, and reduction or disappearance of phase coexistence by action of membrane-interacting molecules have been implicated in membrane function impairment. Here, we applied differential scanning calorimetry, electron paramagnetic resonance (EPR), and non-linear least-squares (NLLS) spectral simulations to study the effects of nicotine, a parasympathomimetic drug, on the two-phase coexistence of dipalmitoyl phosphatidylcholine (DPPC) lipid membrane. The thermodynamic quantities describing the DPPC phase coexistence are temperature dependent, giving rise to non-linear van’t Hoff behavior. Our results showed that nicotine preferentially binds to the fluid phase and modifies the enthalpy and entropy changes of the DPPC heat capacity profile, while marginally perturbing the homogeneous gel and fluid phases. An EPR/NLLS/van’t Hoff analysis of the DPPC phase coexistence revealed that nicotine significantly modified the temperature dependence of the free energy change of the two-phase equilibrium from a cubic to a parabolic behavior, resulting in an alteration of the thermodynamical driving force and the balance of the non-covalent interactions of the lipids in equilibrium. The thermotropic behavior of the enthalpy, entropy, and heat capacity changes, as determined by EPR, indicated that nicotine modified the relative contributions of hydrogen-bonding, electrostatic interactions, and conformational entropy of the lipids to the thermodynamics of the phase coexistence. The predominantly entropically-driven gel-fluid transition in nicotine-free DPPC changes to a temperature-triggered entropically-driven or enthalpically-driven process in nicotine-bound DPPC. Further applications of this thermodynamic EPR/NLLS/van’t Hoff analysis are discussed.

scholarly journals THERMODYNAMIC DUALITY BETWEEN RN BLACK HOLE AND 2D DILATON GRAVITY

2008 ◽  
Vol 23 (02) ◽  
pp. 91-98 ◽  
Author(s):  
YUN SOO MYUNG ◽  
YONG-WAN KIM ◽  
YOUNG-JAI PARK
Keyword(s):  
Black Hole ◽  
Thermodynamic Quantities ◽  
Two Dimensional ◽  
Dilaton Gravity ◽  
Horizon Thermodynamics

All thermodynamic quantities of the Reissner–Nordström (RN) black hole can be obtained from the dilaton and its potential of two-dimensional (2D) dilaton gravity. The dual relations of four thermodynamic laws are also established. Furthermore, the near-horizon thermodynamics of the extremal RN black hole is completely described by the Jackiw–Teitelboim theory which is obtained by perturbing around the AdS2-horizon.

Analysis of the Real Area of Contact Between a Polymeric Magnetic Medium and a Rigid Surface

1984 ◽  
Vol 106 (1) ◽  
pp. 26-34 ◽  
Author(s):  
Bharat Bhushan
Keyword(s):  
Complex Modulus ◽  
Critical Value ◽  
Computer Applications ◽  
Hard Material ◽  
Rigid Surface ◽  
Magnetic Medium ◽  
The Real ◽  
Real Area Of Contact ◽  
The Mean ◽  
Real Area

The statistical analysis of the real area of contact proposed by Greenwood and Williamson is revisited. General and simplified equations for the mean asperity real area of contact, number of contacts, total real area of contact, and mean real pressure as a function of apparent pressure for the case of elastic junctions are presented. The critical value of the mean asperity pressure at which plastic flow starts when a polymer contacts a hard material is derived. Based on this, conditions of elastic and plastic junctions for polymers are defined by a “polymer” plasticity index, Ψp which depends on the complex modulus, Poisson’s ratio, yield strength, and surface topography. Calculations show that most dynamic contacts that occur in a computer-magnetic tape are elastic, and the predictions are supported by experimental evidence. Tape wear in computer applications is small and decreases Ψp by less than 10 percent. The theory presented here can also be applied to rigid and floppy disks.

Numerical Approach for Real Gas Simulations: Part II — Flow Simulation for Supercritical CO2 Centrifugal Compressor

2017 ◽  
Author(s):  
Swati Saxena ◽  
Ramakrishna Mallina ◽  
Francisco Moraga ◽  
Douglas Hofer
Keyword(s):  
Critical Point ◽  
Centrifugal Compressor ◽  
Supercritical Co2 ◽  
Operating Conditions ◽  
Inlet Guide Vane ◽  
Thermodynamic Quantities ◽  
3D Flow ◽  
Real Gas ◽  
The Real ◽  
Operating Range

This paper is presented in two parts. Part I (Tabular fluid properties for real gas analysis) describes an approach to creating a tabular representation of the equation of state that is applicable to any fluid. This approach is applied to generating an accurate and robust tabular representation of the RefProp CO2 properties. Part II (this paper) presents numerical simulations of a low flow coefficient supercritical CO2 centrifugal compressor developed for a closed loop power cycle. The real gas tables presented in part I are used in these simulations. Three operating conditions are simulated near the CO2 critical point: normal day (85 bar, 35C), hot day (105 bar, 50 C) and cold day (70 bar, 20C) conditions. The compressor is a single stage overhung design with shrouded impeller, 155 mm impeller tip diameter and a vaneless diffuser. An axial variable inlet guide vane (IGV) is used to control the incoming swirl into the impeller. An in-house three-dimensional computational fluid dynamics (CFD) solver named TACOMA is used with real gas tables for the steady flow simulations. The equilibrium thermodynamic modeling is used in this study. The real gas effects are important in the desired impeller operating range. It is observed that both the operating range (minimum and maximum volumetric flow rate) and the pressure ratio across the impeller are dependent on the inlet conditions. The compressor has nearly 25% higher operating range on a hot day as compared to the normal day conditions. A condensation region is observed near the impeller leading edge which grows as the compressor operating point moves towards choke. The impeller chokes near the mid-chord due to lower speed of sound in the liquid-vapor region resulting in a sharp drop near the choke side of the speedline. This behavior is explained by analyzing the 3D flow field within the impeller and thermodynamic quantities along the streamline. The 3D flow analysis for the flow near the critical point provides useful insight for the designers to modify the current compressor design for higher efficiency.

scholarly journals Moving contact line on chemically patterned surfaces

2008 ◽  
Vol 605 ◽  
pp. 59-78 ◽  
Author(s):  
XIAO-PING WANG ◽  
TIEZHENG QIAN ◽  
PING SHENG
Keyword(s):  
Contact Line ◽  
Critical Value ◽  
Diffuse Interface ◽  
Patterned Surfaces ◽  
Fluid Interface ◽  
Two Phase ◽  
Stick Slip ◽  
Moving Contact Line ◽  
Moving Contact ◽  
Wetting Fluid

We simulate the moving contact line in two-dimensional chemically patterned channels using a diffuse-interface model with the generalized Navier boundary condition. The motion of the fluid–fluid interface in confined immiscible two-phase flows is modulated by the chemical pattern on the top and bottom surfaces, leading to a stick–slip behaviour of the contact line. The extra dissipation induced by this oscillatory contact-line motion is significant and increases rapidly with the wettability contrast of the pattern. A critical value of the wettability contrast is identified above which the effect of diffusion becomes important, leading to the interesting behaviour of fluid–fluid interface breaking, with the transport of the non-wetting fluid being assisted and mediated by rapid diffusion through the wetting fluid. Near the critical value, the time-averaged extra dissipation scales as U, the displacement velocity. By decreasing the period of the pattern, we show the solid surface to be characterized by an effective contact angle whose value depends on the material characteristics and composition of the patterned surfaces.

scholarly journals The multivariate calculation of material balances of flowsheets for separating ternary mixtures of different physical-chemical nature

2016 ◽  
Vol 11 (3) ◽  
pp. 47-57 ◽  
Author(s):  
A. V. Frolkova ◽  
M. A. Ablizin ◽  
M. A. Mayevskiy ◽  
A. K. Frolkova
Keyword(s):  
Phase Diagrams ◽  
Chemical Nature ◽  
Material Balance ◽  
Ternary Systems ◽  
Butyl Alcohol ◽  
Ternary Mixtures ◽  
Two Phase ◽  
Physical Chemical ◽  
Alcohol Water

An approach to the determination of free variables required for calculating the material balance of the flowsheet of ternary mixtures separation is presented. Phase diagrams of the considered ternary systems are characterized by the presence of a two-phase splitting area and by the presence of different amounts of azeotropes (classes 3.1.0, 3.1.1, 3.2.1 and 3.3.1). For all the systems flowsheets containing three rectification columns and a florentine vessel for separation were suggested. The multivariance of the solution of the balance problem was shown. The approach was illustrated by the example of real ternary systems characterized by different phase diagrams (methanol - chloroform - water, butyl alcohol - water - toluene, nitromethane - hexane - water). The parameters of the rectification columns were presented.

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