Optimization of equation of state and burn model parameters for explosives

In this paper, evolution of a Friedmann–Robertson–Walker universe is studied in a higher derivative theory of gravity. The relativistic solutions admitting hybrid expansion law of the universe are explored here. Hybrid expansion law is a general form of scale factor from which one can recover both the power-law expansion and exponential expansion as a special case. The hybrid expansion law is interesting as it addresses the early deceleration phase and presents accelerating phase satisfactorily. It is found that an inflationary scenario with hybrid expansion law is permitted in the [Formula: see text] gravity fairly well. We consider universe filled with cosmic fluid that describes by an equation of state (EoS) parameter which varies with time. Consequently, we analyze the time variation of energy density parameter, cosmic pressure, equation of state parameter, deceleration parameter and jerk parameter in the cosmological model. The constraints of the model parameters imposed by the cosmological observational data set are determined. The present value of the deceleration parameter [Formula: see text], EoS parameter and the epoch at which the transition of decelerated phase to accelerated phase are estimated. In the higher derivative theory, we obtain some new and interesting cosmological solutions relevant for building cosmological models.

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Impact of generalized polytropic equation of state on charged anisotropic polytropes

The European Physical Journal C ◽

10.1140/epjc/s10052-020-7647-x ◽

2020 ◽

Vol 80 (2) ◽

Author(s):

S. A. Mardan ◽

M. Rehman ◽

I. Noureen ◽

R. N. Jamil

Keyword(s):

Equation Of State ◽

Speed Of Sound ◽

Graphical Analysis ◽

Maxwell Field ◽

Anisotropic Fluid ◽

Polytropic Index ◽

Model Parameters ◽

Field Equations ◽

Polytropic Equation ◽

Fluid Configuration

Abstract In this paper, generalized polytropic equation of state is used to get new classes of polytropic models from the solution of Einstein-Maxwell field equations for charged anisotropic fluid configuration. The models are developed for different values of polytropic index $$n=1,~\frac{1}{2},~2$$n=1,12,2. Masses and radii of eight different stars have been regained with the help of developed models. The speed of sound technique and graphical analysis of model parameters is used for the viability of developed models. The analysis of models indicates they are well behaved and physically viable.

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RELATIVISTIC STELLAR MODEL ADMITTING A QUADRATIC EQUATION OF STATE

International Journal of Modern Physics D ◽

10.1142/s0218271813500740 ◽

2013 ◽

Vol 22 (13) ◽

pp. 1350074 ◽

Cited By ~ 41

Author(s):

R. SHARMA ◽

B. S. RATANPAL

Keyword(s):

Equation Of State ◽

Analytic Solution ◽

Geometric Interpretation ◽

Quadratic Equation ◽

Stellar Model ◽

Model Parameters ◽

Spherically Symmetric ◽

Quadratic Equation Of State ◽

Anisotropic Star

A class of solutions describing the interior of a static spherically symmetric compact anisotropic star is reported. The analytic solution has been obtained by utilizing the Finch and Skea [Class. Quantum Grav.6 (1989) 467] ansatz for the metric potential grr which has a clear geometric interpretation for the associated background spacetime. Based on physical grounds, appropriate bounds on the model parameters have been obtained and it has been shown that the model admits an equation of state (EOS) which is quadratic in nature.

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THE EFFECT OF DIFFERENT OBSERVATIONAL DATA IN CONSTRAINING COSMOLOGICAL PARAMETERS

International Journal of Modern Physics Conference Series ◽

10.1142/s201019451200579x ◽

2012 ◽

Vol 10 ◽

pp. 85-94 ◽

Cited By ~ 5

Author(s):

YUNGUI GONG ◽

QING GAO ◽

ZONG-HONG ZHU

Keyword(s):

Dark Energy ◽

Equation Of State ◽

Observational Data ◽

Cosmological Parameters ◽

State Parameter ◽

Wilkinson Microwave Anisotropy Probe ◽

Model Parameters ◽

Type Ia Supernova ◽

Equation Of State Parameter ◽

Type Ia

We use the SNLS3 compilation of 472 type Ia supernova data, the baryon acoustic oscillation measurement of distance, and the cosmic microwave background radiation data from the seven year Wilkinson Microwave Anisotropy Probe to study the effect of their different combinations on the fittings of cosmological parameters. Neither BAO nor WMAP7 data alone gives good constraint on the equation of state parameter of dark energy, but both WMAP7 data and BAO data help type Ia supernova data break the degeneracies among the model parameters, hence tighten the constraint on the variation of equation of state parameter wa, and WMAP7 data does the job a little better. Although BAO and WMAP7 data provide reasonably good constraints on Ωm and Ωk, it is not able to constrain the dynamics of dark energy, we need SNe Ia data to probe the property of dark energy, especially the variation of the equation of state parameter of dark energy. For the SNLS SNe Ia data, the nuisance parameters α and β are consistent for all different combinations of the above data. Their impacts on the fittings of cosmological parameters are minimal. ΛCDM model is consistent with current observational data.

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Sensitivity Analysis of Tunable Equation of State Material Model In Pulsed Mercury Target Simulation

10.1115/pvp2021-60940 ◽

2021 ◽

Author(s):

Lianshan Lin ◽

Drew Winder

Keyword(s):

High Pressure ◽

Equation Of State ◽

Material Model ◽

High Energy ◽

Model Parameters ◽

Strain Response ◽

Target Structure ◽

Stationary Target ◽

Pressure Region ◽

High Pressure Region

Abstract A pulsed neutron spallation target is subjected to very short but intense loads from repeated proton pulses. Approximately 60% of the energy from each proton pulse is deposited into the mercury target material and the stainless-steel target structure, leading to a high-pressure region in both the stationary target structure and the flowing mercury. The high-pressure region propagates and leads to fluid-structure interaction. The resultant loading on the target structure containing liquid mercury is difficult to predict, although various simulation approaches and material models for the mercury have been tried. To date, the best match of simulation to experimental data is obtained by using an equation of state (EOS) material model with a specified tensile cutoff pressure, which simulates the cavitation threshold. The inclusion of a threshold to represent cavitation is key to the successful predictions of stress waves triggered by the high-energy pulse striking the mercury and vessel. However, recent measurements of target structure strain show that significant discrepancies remain between the measured and simulated strain values in the EOS mercury model. These differences grow when noncondensable helium gas is intentionally injected into the flowing mercury to reduce the loading on the structure. An EOS-based proportional–integral–derivative (PID) mercury model has been proposed to reduce the gap between the measured and simulated vessel strain responses for targets with gas injection. The conceptual and numerical description and initial investigation of the PID model are presented in previous work. Further studies of this PID model — including the sensitivity of the structure’s strain response to model parameters (the tensile cutoff, PID parameters Kp, Ki, and Kd) — are reported in this article. Results show the strain response is more sensitive to changes in the tensile cutoff value than to changes in the model parameters Kp, Ki, and Kd. These results will aid in future work where the model parameters will be optimized to match simulation data to strain measurements.

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Bayesian Analysis for Extracting Properties of the Nuclear Equation of State from Observational Data Including Tidal Deformability from GW170817

Universe ◽

10.3390/universe5020061 ◽

2019 ◽

Vol 5 (2) ◽

pp. 61 ◽

Cited By ~ 12

Author(s):

Alexander Ayriyan ◽

David Alvarez-Castillo ◽

David Blaschke ◽

Hovik Grigorian

Keyword(s):

Equation Of State ◽

Bayesian Analysis ◽

Quark Matter ◽

Equations Of State ◽

Compact Star ◽

String Tension ◽

Model Parameters ◽

Analysis Method ◽

Hybrid Stars ◽

Limiting Case

We develop a Bayesian analysis method for selecting the most probable equation of state under a set of constraints from compact star physics, which now include the tidal deformability from GW170817. We apply this method for the first time to a two-parameter family of hybrid equations of state that is based on realistic models for the hadronic phase (KVORcut02) and the quark matter phase (SFM α ) which produce a third family of hybrid stars in the mass–radius diagram. One parameter ( α ) characterizes the screening of the string tension in the string-flip model of quark matter while the other ( Δ P ) belongs to the mixed phase construction that mimics the thermodynamics of pasta phases and includes the Maxwell construction as a limiting case for Δ P = 0 . We present the corresponding results for compact star properties like mass, radius and tidal deformabilities and use empirical data for them in the newly developed Bayesian analysis method to obtain the probabilities for the model parameters within their considered range.

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Reconstruction of interaction rate in holographic dark energy model with Hubble horizon as the infrared cut-off

International Journal of Modern Physics D ◽

10.1142/s021827181750136x ◽

2017 ◽

Vol 26 (11) ◽

pp. 1750136 ◽

Cited By ~ 4

Author(s):

Abdulla Al Mamon

Keyword(s):

Dark Energy ◽

Equation Of State ◽

Deceleration Parameter ◽

Energy Equation ◽

Present Model ◽

Holographic Dark Energy ◽

State Parameter ◽

Model Parameters ◽

Interaction Rate ◽

Equation Of State Parameter

This work is the reconstruction of the interaction rate of holographic dark energy whose infrared cut-off scale is set by the Hubble length. We have reconstructed the interaction rate between dark matter and the holographic dark energy for a specific parameterization of the effective equation-of-state parameter. We have obtained observational constraints on the model parameters using the latest type Ia supernova (SNIa), baryon acoustic oscillations (BAO) and cosmic microwave background (CMB) radiation datasets. We have found that for the present model, the interaction rate increases with expansion and remains positive throughout the evolution. For a comprehensive analysis, we have also compared the reconstructed results of the interaction rate with other well-known holographic dark energy models. The nature of the deceleration parameter, the statefinder parameters and the dark energy equation-of-state parameter have also been studied for the present model. It has been found that the deceleration parameter favors the past decelerated and recent accelerated expansion phase of the universe. It has also been found that the dark energy equation-of-state parameter shows a phantom nature at the present epoch.

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Barotropic fluid compatible parametrizations of dark energy

The European Physical Journal C ◽

10.1140/epjc/s10052-020-8199-9 ◽

2020 ◽

Vol 80 (7) ◽

Author(s):

Dalibor Perković ◽

Hrvoje Štefančić

Keyword(s):

Dark Energy ◽

Equation Of State ◽

Speed Of Sound ◽

Functional Form ◽

State Parameter ◽

Model Parameters ◽

Barotropic Fluid ◽

Energy Models ◽

Equation Of State Parameter ◽

Fundamental Requirement

Abstract Parametrizations of equation of state parameter as a function of the scale factor or redshift are frequently used in dark energy modeling. The question investigated in this paper is if parametrizations proposed in the literature are compatible with the dark energy being a barotropic fluid. The test of this compatibility is based on the functional form of the speed of sound squared, which for barotropic fluid dark energy follows directly from the function for the Equation of state parameter. The requirement that the speed of sound squared should be between 0 and speed of light squared provides constraints on model parameters using analytical and numerical methods. It is found that this fundamental requirement eliminates a large number of parametrizations as barotropic fluid dark energy models and puts strong constraints on parameters of other dark energy parametrizations.

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Hydrate Equilibrium Modelling with the Cubic two-state Equation of State

Journal of the Mexican Chemical Society ◽

10.29356/jmcs.v60i4.114 ◽

2017 ◽

Vol 60 (4) ◽

Cited By ~ 1

Author(s):

Edgar Galicia-Andrés ◽

Milton Medeiros

Keyword(s):

Equation Of State ◽

Gas Hydrates ◽

Hydrate Formation ◽

Triethylene Glycol ◽

State Equation ◽

Model Parameters ◽

Equilibrium Pressure ◽

Multicomponent Gas ◽

Pure Compounds ◽

Equilibrium Data

A combination of the cubic two-state equation of state and the van der Waals–Platteeuw model was employed for the description of the hydrate formation thermodynamics, with and without inhibitors. The model parameters were determined from the properties of pure compounds and from phase equilibrium data of binary gas–water and water–inhibitor mixtures. With these parameters, predictions were performed for multicomponent gas–water–inhibitor systems. For single-gas hydrates, the average absolute deviations found for equilibrium pressure did not exceed 8%, whereas for multi-gas hydrates, these deviations were 23% maximum. The proposed model produced good predictions in the presence of inhibitors (methanol, ethanol, ethylene glycol and triethylene glycol), with increasing deviations at higher concentrations of inhibitors.

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