The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Conrad Winters - One of the best experts on this subject based on the ideXlab platform.
-
application of chaos analysis to pressure fluctuation data from a fluidized bed dryer containing pharmaceutical granule
Powder Technology, 2004Co-Authors: Gareth Chaplin, Todd Pugsley, Conrad WintersAbstract:The S-statistic, a statistical test between chaotic attractors for fluidized systems introduced by van Ommen et al. [J.R. van Ommen, Monitoring fluidized bed Hydrodynamics, PhD thesis, Technical University of Delft (2001).; AIChe J., 46 (11) (2000), 2183] has been applied to pressure fluctuations collected in a conical fluidized bed of dry pharmaceutical granule as well as a fluidized bed of wet granule as it progresses to the dry state. In a dry bed, the S-statistic has been found sensitive to the particle size distribution (PSD). Changes in bed Hydrodynamics arising from PSD have been found to be most easily resolved at low gas velocities, indicating segregation at superficial velocities less than 2 m/s. In a drying bed, two stable states have been identified. These states correspond to visual observations of the presence of a centralized core of bubbles in a bed of high moisture content and more uniform fluidization throughout the bed cross-section toward the end of the drying process. The effect of moisture has been found to dominate the hydrodynamic changes taking place within the bed in the drying process identified with the S-statistic. The hydrodynamic changes identified by the S-statistic are not discerned by frequency and amplitude analysis techniques. Response of the S-statistic to the hydrodynamic changes associated with drying indicates the potential application of this technique to the quantification of fluidized bed hydrodynamic behavior.
Aleksas Mazeliauskas - One of the best experts on this subject based on the ideXlab platform.
-
matching the nonequilibrium initial stage of heavy ion collisions to Hydrodynamics with qcd kinetic theory
Physical Review Letters, 2019Co-Authors: Aleksi Kurkela, Jeanfrancois Paquet, Soren Schlichting, Derek Teaney, Aleksas MazeliauskasAbstract:: High-energy nuclear collisions produce a nonequilibrium plasma of quarks and gluons which thermalizes and exhibits hydrodynamic flow. There are currently no practical frameworks to connect the early particle production in classical field simulations to the subsequent hydrodynamic evolution. We build such a framework using nonequilibrium Green's functions, calculated in QCD kinetic theory, to propagate the initial energy-momentum tensor to the hydrodynamic phase. We demonstrate that this approach can be easily incorporated into existing hydrodynamic simulations, leading to stronger constraints on the energy density at early times and the transport properties of the QCD medium. Based on (conformal) scaling properties of the Green's functions, we further obtain pragmatic bounds for the applicability of Hydrodynamics in nuclear collisions.
-
effective kinetic description of event by event pre equilibrium dynamics in high energy heavy ion collisions
Physical Review C, 2019Co-Authors: Aleksi Kurkela, Jeanfrancois Paquet, Soren Schlichting, Aleksas Mazeliauskas, Derek TeaneyAbstract:We develop a macroscopic description of the space-time evolution of the energy-momentum tensor during the pre-equilibrium stage of a high-energy heavy-ion collision. Based on a weak coupling effective kinetic description of the microscopic equilibration process (\`a la "bottom-up"), we calculate the non-equilibrium evolution of the local background energy-momentum tensor as well as the non-equilibrium linear response to transverse energy and momentum perturbations for realistic boost-invariant initial conditions for heavy ion collisions. We demonstrate how this framework can be used on an event-by-event basis to propagate the energy momentum tensor from far-from-equilibrium initial state models, e.g. IP-Glasma, to the time $\tau_\text{hydro}$ when the system is well described by relativistic viscous Hydrodynamics. The subsequent hydrodynamic evolution becomes essentially independent of the hydrodynamic initialization time $\tau_\text{hydro}$ as long as $\tau_\text{hydro}$ is chosen in an appropriate range where both kinetic and hydrodynamic descriptions overlap. We find that for $\sqrt{s_{NN}}=2.76\,\text{TeV}$ central Pb-Pb collisions, the typical time scale when viscous Hydrodynamics with shear viscosity over entropy ratio $\eta/s=0.16$ becomes applicable is $\tau_\text{hydro}\sim 1\,\text{fm/c}$ after the collision.
Aleksi Kurkela - One of the best experts on this subject based on the ideXlab platform.
-
matching the nonequilibrium initial stage of heavy ion collisions to Hydrodynamics with qcd kinetic theory
Physical Review Letters, 2019Co-Authors: Aleksi Kurkela, Jeanfrancois Paquet, Soren Schlichting, Derek Teaney, Aleksas MazeliauskasAbstract:: High-energy nuclear collisions produce a nonequilibrium plasma of quarks and gluons which thermalizes and exhibits hydrodynamic flow. There are currently no practical frameworks to connect the early particle production in classical field simulations to the subsequent hydrodynamic evolution. We build such a framework using nonequilibrium Green's functions, calculated in QCD kinetic theory, to propagate the initial energy-momentum tensor to the hydrodynamic phase. We demonstrate that this approach can be easily incorporated into existing hydrodynamic simulations, leading to stronger constraints on the energy density at early times and the transport properties of the QCD medium. Based on (conformal) scaling properties of the Green's functions, we further obtain pragmatic bounds for the applicability of Hydrodynamics in nuclear collisions.
-
effective kinetic description of event by event pre equilibrium dynamics in high energy heavy ion collisions
Physical Review C, 2019Co-Authors: Aleksi Kurkela, Jeanfrancois Paquet, Soren Schlichting, Aleksas Mazeliauskas, Derek TeaneyAbstract:We develop a macroscopic description of the space-time evolution of the energy-momentum tensor during the pre-equilibrium stage of a high-energy heavy-ion collision. Based on a weak coupling effective kinetic description of the microscopic equilibration process (\`a la "bottom-up"), we calculate the non-equilibrium evolution of the local background energy-momentum tensor as well as the non-equilibrium linear response to transverse energy and momentum perturbations for realistic boost-invariant initial conditions for heavy ion collisions. We demonstrate how this framework can be used on an event-by-event basis to propagate the energy momentum tensor from far-from-equilibrium initial state models, e.g. IP-Glasma, to the time $\tau_\text{hydro}$ when the system is well described by relativistic viscous Hydrodynamics. The subsequent hydrodynamic evolution becomes essentially independent of the hydrodynamic initialization time $\tau_\text{hydro}$ as long as $\tau_\text{hydro}$ is chosen in an appropriate range where both kinetic and hydrodynamic descriptions overlap. We find that for $\sqrt{s_{NN}}=2.76\,\text{TeV}$ central Pb-Pb collisions, the typical time scale when viscous Hydrodynamics with shear viscosity over entropy ratio $\eta/s=0.16$ becomes applicable is $\tau_\text{hydro}\sim 1\,\text{fm/c}$ after the collision.
Gareth Chaplin - One of the best experts on this subject based on the ideXlab platform.
-
application of chaos analysis to pressure fluctuation data from a fluidized bed dryer containing pharmaceutical granule
Powder Technology, 2004Co-Authors: Gareth Chaplin, Todd Pugsley, Conrad WintersAbstract:The S-statistic, a statistical test between chaotic attractors for fluidized systems introduced by van Ommen et al. [J.R. van Ommen, Monitoring fluidized bed Hydrodynamics, PhD thesis, Technical University of Delft (2001).; AIChe J., 46 (11) (2000), 2183] has been applied to pressure fluctuations collected in a conical fluidized bed of dry pharmaceutical granule as well as a fluidized bed of wet granule as it progresses to the dry state. In a dry bed, the S-statistic has been found sensitive to the particle size distribution (PSD). Changes in bed Hydrodynamics arising from PSD have been found to be most easily resolved at low gas velocities, indicating segregation at superficial velocities less than 2 m/s. In a drying bed, two stable states have been identified. These states correspond to visual observations of the presence of a centralized core of bubbles in a bed of high moisture content and more uniform fluidization throughout the bed cross-section toward the end of the drying process. The effect of moisture has been found to dominate the hydrodynamic changes taking place within the bed in the drying process identified with the S-statistic. The hydrodynamic changes identified by the S-statistic are not discerned by frequency and amplitude analysis techniques. Response of the S-statistic to the hydrodynamic changes associated with drying indicates the potential application of this technique to the quantification of fluidized bed hydrodynamic behavior.
Derek Teaney - One of the best experts on this subject based on the ideXlab platform.
-
matching the nonequilibrium initial stage of heavy ion collisions to Hydrodynamics with qcd kinetic theory
Physical Review Letters, 2019Co-Authors: Aleksi Kurkela, Jeanfrancois Paquet, Soren Schlichting, Derek Teaney, Aleksas MazeliauskasAbstract:: High-energy nuclear collisions produce a nonequilibrium plasma of quarks and gluons which thermalizes and exhibits hydrodynamic flow. There are currently no practical frameworks to connect the early particle production in classical field simulations to the subsequent hydrodynamic evolution. We build such a framework using nonequilibrium Green's functions, calculated in QCD kinetic theory, to propagate the initial energy-momentum tensor to the hydrodynamic phase. We demonstrate that this approach can be easily incorporated into existing hydrodynamic simulations, leading to stronger constraints on the energy density at early times and the transport properties of the QCD medium. Based on (conformal) scaling properties of the Green's functions, we further obtain pragmatic bounds for the applicability of Hydrodynamics in nuclear collisions.
-
effective kinetic description of event by event pre equilibrium dynamics in high energy heavy ion collisions
Physical Review C, 2019Co-Authors: Aleksi Kurkela, Jeanfrancois Paquet, Soren Schlichting, Aleksas Mazeliauskas, Derek TeaneyAbstract:We develop a macroscopic description of the space-time evolution of the energy-momentum tensor during the pre-equilibrium stage of a high-energy heavy-ion collision. Based on a weak coupling effective kinetic description of the microscopic equilibration process (\`a la "bottom-up"), we calculate the non-equilibrium evolution of the local background energy-momentum tensor as well as the non-equilibrium linear response to transverse energy and momentum perturbations for realistic boost-invariant initial conditions for heavy ion collisions. We demonstrate how this framework can be used on an event-by-event basis to propagate the energy momentum tensor from far-from-equilibrium initial state models, e.g. IP-Glasma, to the time $\tau_\text{hydro}$ when the system is well described by relativistic viscous Hydrodynamics. The subsequent hydrodynamic evolution becomes essentially independent of the hydrodynamic initialization time $\tau_\text{hydro}$ as long as $\tau_\text{hydro}$ is chosen in an appropriate range where both kinetic and hydrodynamic descriptions overlap. We find that for $\sqrt{s_{NN}}=2.76\,\text{TeV}$ central Pb-Pb collisions, the typical time scale when viscous Hydrodynamics with shear viscosity over entropy ratio $\eta/s=0.16$ becomes applicable is $\tau_\text{hydro}\sim 1\,\text{fm/c}$ after the collision.
