Article
Mathematics, Applied
Takashi Arima
Summary: This study explores the characteristic velocities of molecular rotational and vibrational relaxation processes in a van der Waals gas, estimating lower and upper bounds based on rarefied gases and the spinodal curve. Additionally, the dispersion relation of linear waves, including phase velocity, attenuation factor, and attenuation per wavelength in a low-frequency range, is investigated in detail.
RICERCHE DI MATEMATICA
(2021)
Article
Physics, Fluids & Plasmas
Milana Pavic-Colic, Srboljub Simic
Summary: This paper presents a six-field theory for the mixture of polyatomic gases and calculates phenomenological coefficients through a combined macroscopic/kinetic closure procedure.
Article
Thermodynamics
Donat Weniger, Philip L. Varghese, Julia Kowalski, Manuel Torrilhon
Summary: This study investigates the influence of kinetic theory-based non-equilibrium thermodynamic models on the classical Stefan problem for deposition or sublimation processes, revealing significant differences from the classical model as the level of rarefaction increases.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Chemistry, Physical
Grzegorz Szamel
Summary: In this study, an alternative theory for the relaxation of density fluctuations in glass-forming fluids is proposed. By deriving a local-in-time equation of motion for the density correlation function, the significance of the Franz-Parisi free energy functional for the evolution of the density correlation function is identified.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Physics, Nuclear
Derek Everett, Chandrodoy Chattopadhyay, Ulrich Heinz
Summary: Coupling hadronic kinetic theory models to fluid dynamics in heavy ion collision studies requires a prescription for particlization. Existing models are based on assumptions about microscopic degrees of freedom beyond fluid dynamical history. We propose an alternative method using only macroscopic information, derived from connections between information theory and statistical mechanics.
Article
Computer Science, Interdisciplinary Applications
Huayan Shang, Siyu Sun, Haijun Huang, Wenxiang Wu
Summary: This study introduces a new dynamic pedestrian flow assignment model based on Decision Field Theory (DFT) and Cell Transmission Model (CTM) to explore individual decision-making processes in pedestrian evacuation. The research shows that various factors such as initial pedestrian distributions, individual preferences, and environmental conditions can influence pedestrian choices during evacuation. Furthermore, it is observed that even in the same area, pedestrians may exhibit different route and exit choices, and preference reversals can be depicted in the model.
SIMULATION MODELLING PRACTICE AND THEORY
(2021)
Article
Biotechnology & Applied Microbiology
Marina de Leeuw, Marta R. A. Matos, Lars Keld Nielsen
Summary: Kinetic models are important for understanding metabolic systems. This paper presents a detailed kinetic model for the central carbon metabolism of Escherichia coli, which has been validated and can be used for studying cellular metabolism and metabolic pathway design.
METABOLIC ENGINEERING
(2023)
Article
Chemistry, Physical
Shinichi Ichikawa
Summary: This study reveals the inherent nature of a heterogeneous catalytic reaction system by emphasizing the correlation between kinetics and thermodynamics. Through the common results obtained in different reaction settings, it conveys the essence of catalytic reactions. The efficacy and profundity of analytical mathematics approach are highlighted in disclosing the fundamental nature of catalytic reactions.
JOURNAL OF CATALYSIS
(2021)
Article
Physics, Nuclear
Sunil Jaiswal, Chandrodoy Chattopadhyay, Lipei Du, Ulrich Heinz, Subrata Pal
Summary: In this study, the nonconformal dynamics of a system undergoing Bjorken expansion is investigated using kinetic theory and second-order Chapman-Enskog hydrodynamics. The concept of free-streaming fixed lines for scaled shear and bulk stresses is utilized, and it is shown that these fixed lines act as early-time attractors and repellors of the evolution. Unlike the conformal scenario, both kinetic theory and hydrodynamics predict the absence of attractor behavior in the normalized shear stress channel. A modified anisotropic hydrodynamic description is presented to accurately describe the far-from-equilibrium attractor.
Article
Chemistry, Analytical
Zhipeng Li, Jinghao Li, Hejuan Chen
Summary: This paper analyzes the influence of structural parameters on the fluid power sound source and identifies the parameters controlling the sound pressure amplitude and frequency. The study shows that the annulus, the confronting distance, and cavity length can impact the sound pressure amplitude, with the confronting distance being the most sensitive parameter. The length of the resonant cavity has the greatest effect on the sound pressure frequency.
Article
Physics, Fluids & Plasmas
R. Hilfer
Summary: Traditional Boltzmann-Gibbs statistical mechanics is not applicable to systems with unstable interactions. This article revisits the foundations of statistical physics and introduces generalized ensembles for unstable interactions. The results show that unstable systems can exhibit thermodynamic normality and extensivity.
Article
Computer Science, Software Engineering
Carl Schissler, Gregor Muckl, Paul Calamia
Summary: In the context of geometric acoustic simulation, a dynamic geometric diffraction approach is proposed to efficiently simulate high-order diffraction paths by using a preprocessing module and runtime algorithm. This technique can effectively handle a large number of sources and simulate high-order diffraction effects in complex geometric scenes.
ACM TRANSACTIONS ON GRAPHICS
(2021)
Article
Chemistry, Physical
Jacob S. DeHovitz, Todd K. Hyster
Summary: Isomerizations are chemical processes that transform a compound into a different structure while maintaining the same chemical formula. The recent resurgence of photochemistry has led to an increased focus on using radicals and diradicals as key intermediates for isomerization. Understanding the mechanisms behind these approaches can help streamline chemical synthesis.
Article
Chemistry, Physical
Jacob S. DeHovitz, Todd K. Hyster
Summary: This article mainly introduces the isomerization process in chemical reactions, where a compound is transformed into another structure while maintaining the same chemical formula. With the development of photochemistry, there has been an increasing number of isomerization reactions leveraging radicals and diradicals as key intermediates. The article also explores dynamic approaches such as isomerizations, deracemizations, and dynamic kinetic resolutions.
Article
Physics, Particles & Fields
Yein Lee, Matthew Richards, Sean Stotyn, Miok Park
Summary: In this study, the thermodynamics of Einstein-Maxwell (-dilaton) theory for an asymptotically flat spacetime in a quasilocal frame was investigated. A quasilocal thermodynamic potential was defined, and quasilocal energy, surface pressure, and entropy were calculated. The study found that for dyonic black hole solutions with dynamic dilaton field, there is a non-trivial dilaton contribution in the quasilocal first law.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Article
Mathematics, Applied
Tommaso Ruggeri, Qinghua Xiao, Huijiang Zhao
Summary: In this article, the fundamental properties of nonlinear waves in Euler's relativistic system with energy constitutive equations related to Synge equation are studied. By delicate estimates of Bessel functions, important results are proved, such as speed of sound limit, non-linearity of acoustic waves, compatibility of Rankine-Hugoniot relations with entropy growth, and uniqueness of the resolvability of the Riemann initial value problem.
ARCHIVE FOR RATIONAL MECHANICS AND ANALYSIS
(2021)
Article
Mathematics, Applied
Seung-Yeal Ha, Myeongju Kang, Hansol Park, Tommaso Ruggeri, Woojoo Shim
Summary: The thermodynamic Kuramoto model with coupling between phase and temperature fields is studied for uniform stability and mean-field limit. Through estimates of distance between solutions, the model's stability with respect to initial data is established. Using BBGKY hierarchy and particle-in-cell method, a Vlasov type mean-field equation is derived in the large-oscillator limit, with global-in-time measure-valued solutions and stability estimates obtained.
QUARTERLY OF APPLIED MATHEMATICS
(2021)
Article
Mechanics
Takashi Arima, Maria Cristina Carrisi, Sebastiano Pennisi, Tommaso Ruggeri
Summary: Inspired by Pennisi (2021) in the relativistic framework, this study proposes a new natural physical hierarchy of moments to describe classical rarefied non-polytropic polyatomic gas within the framework of Molecular Rational Extended Thermodynamics. By considering the case of 15 moments and utilizing the variational method of the Maximum Entropy Principle, the system is closed and the convexity of entropy is proven, with the possibility of putting the system in symmetric form. This richer kinetic framework may have potential applications in biomathematics and other fields where kinetic models have been successfully applied recently.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2021)
Article
Physics, Multidisciplinary
Takashi Arima, Maria Cristina Carrisi, Sebastiano Pennisi, Tommaso Ruggeri
Summary: A relativistic extension of thermodynamics for polyatomic gases is proposed, taking into account the total energy of the system and the internal mode energy of molecules. Moment equations associated with the Boltzmann-Chernikov equation are derived and a closed system of equations is obtained. The system satisfies the entropy principle, making it symmetric hyperbolic and well-posed. The ultra-relativistic and classical limits are also studied, and subsystems with 14 and 6 moments are derived.
Article
Mechanics
Tommaso Ruggeri, Shigeru Taniguchi
Summary: The shock structure in a binary mixture of polyatomic Eulerian gases with different degrees of freedom is studied using the multi-temperature model of rational extended thermodynamics. The possible sub-shocks are identified based on the change in the Mach number and equilibrium concentration. The regions for sub-shock formation are determined and the relationship between acceleration waves and sub-shocks is derived.
Article
Mechanics
Takashi Arima, Andrea Mentrelli, Tommaso Ruggeri
Summary: The paper aims to demonstrate that a general system of 14 balance laws for a compressible, possibly dense, gas, which satisfies the universal principles of Rational Extended Thermodynamics (RET), converges to the Navier-Stokes-Fourier equations in the first step of the Maxwellian iteration. Furthermore, in a theory not far from equilibrium, the study shows that the production terms of the hyperbolic system can be uniquely determined by assigning the heat conductivity, shear viscosity, and bulk viscosity. The obtained results are tested on the RET theories for rarefied monatomic and polyatomic gases.
INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS
(2023)
Article
Physics, Multidisciplinary
Takashi Arima, Masaru Sugiyama
Summary: This study investigates the nonequilibrium flows of a rarefied polyatomic gas through a diverging nozzle under the effect of dynamic pressure. It is found that even in a diverging nozzle, choking phenomena can occur if the gas at the nozzle inlet is in a nonequilibrium state. Furthermore, the controllability of gas flows in a nozzle by manipulating the temperature of molecular internal modes such as molecular rotation and vibration is discussed.
Article
Mathematics, Applied
Tommaso Ruggeri, Shigeru Taniguchi
Summary: In this study, we continue to investigate the formation of sub-shocks in a binary mixture of gases, taking into account the dissipation caused by bulk viscosity in both constituents. Using a mixture of gases model proposed by T. Arima et al., we classify the regions based on concentration and Mach number to determine whether sub-shocks may exist inside the shock profiles of the constituents. Numerical calculations of the shock profiles for various gas mixtures show that the presence of dissipation leads to a more regularized shock profile and a reduction in the amplitude of sub-shocks compared to non-dissipative gases.
RICERCHE DI MATEMATICA
(2023)
Article
Mathematics, Applied
Takashi Arima, Masaru Sugiyama
Summary: Flows of rarefied polyatomic gas in a nozzle with simple geometry were numerically studied using the rational extended thermodynamics theory with six independent fields (RET6). The study focused on the effect of dynamic pressure (nonequilibrium part of the pressure) on nozzle gas flows. By comparing the flow profiles with those predicted by the Euler theory, the development of nonequilibrium state of gas along the flow was investigated. Qualitatively different flow profiles from those predicted by the Euler theory were observed under certain conditions. Choking phenomena were also observed based on RET6. These findings confirm the usefulness of RET6 theory in analyzing nozzle gas flows.
RICERCHE DI MATEMATICA
(2023)
Article
Physics, Fluids & Plasmas
Takashi Arima, Tommaso Ruggeri
Summary: This paper aims to construct a new hierarchy of molecular extended thermodynamics for classical rarefied polyatomic gases, incorporating internal degrees of freedom, by deducing a new hierarchy from the classical limit of relativistic theory of moments. The field equations for 15 moments of the distribution function are closed with the maximum entropy principle, showing convergence to the Kremer 14-moment system in the monatomic limit.
Article
Mathematics, Applied
Tommaso Ruggeri, Qinghua Xiao
Summary: The study investigated the Riemann problem of the relativistic Euler system for rarefied monatomic and diatomic gases, focusing on the classical and ultrarelativistic limits of the results and showing agreement with existing literature.
RICERCHE DI MATEMATICA
(2021)
Article
Mathematics, Applied
Tommaso Ruggeri
Summary: This paper discusses a rarefied polyatomic gas with a non-polytropic equation of state and uses the maximum entropy principle (MEP) to obtain the closure of the binary hierarchy of 14 moments associated with the Boltzmann equation. The closed partial differential system is symmetric hyperbolic and well-posed for the Cauchy problem. In the limiting case of polytropic gas, it confirms previous results and completes the equivalence between different closure methods for non-polytropic gas.
RICERCHE DI MATEMATICA
(2021)
Article
Physics, Multidisciplinary
Tinggui Chen, Baizhan Xia, Dejie Yu, Chuanxing Bi
Summary: This study proposes a gradient phononic crystal structure for enhanced acoustic sensing. By breaking the symmetry of the PC structure, topologically protected edge states are introduced, resulting in topological acoustic rainbow trapping. The robustness and enhancement properties are verified numerically and experimentally.
