Unconventional relaxation of hydrodynamic modes in anharmonic chains under strong pressure fluctuations

Journal of Physics A Mathematical and Theoretical ◽

10.1088/1751-8121/ac463d ◽

2021 ◽

Author(s):

Da Ke ◽

Wei Zhong ◽

Sergey V Dmitriev ◽

Daxing Xiong

Keyword(s):

Thermal Transport ◽

Numerical Scheme ◽

Pressure Fluctuations ◽

Hydrodynamic Theory ◽

Hydrodynamic Modes ◽

Large Pressure

Abstract We develop an effective numerical scheme to capture hydrodynamic modes in general classical anharmonic chains. This scheme is based on the hydrodynamic theory suggested by Ernst-Hauge-van Leeuwen, which takes full role of pressure fluctuations into account. With this scheme we show that the traditional pictures given by the current nonlinear fluctuating hydrodynamic theory are valid only when the system's pressure is zero and the pressure fluctuations are weak. For nonvanishing pressure, the hydrodynamic modes can, however, respond to small and large pressure fluctuations and relax in some distinct manners. Our results shed new light on understanding thermal transport from the perspective of hydrodynamic theory.

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Thermal transport through a one-dimensional quantum spin-1/2 chain heterostructure: The role of three-site spin interaction

The European Physical Journal B ◽

10.1140/epjb/e2012-30793-6 ◽

2012 ◽

Vol 86 (1) ◽

Cited By ~ 69

Author(s):

H. Wu ◽

Y. Wang ◽

W. -J. Gong ◽

Y. Han ◽

X. -H. Chen

Keyword(s):

Thermal Transport ◽

Quantum Spin ◽

Spin Interaction ◽

One Dimensional

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Facilitating thermal transport across Si/Ge interface via mass-graded interlayer: The role of elastic and inelastic phonon processes

Journal of Applied Physics ◽

10.1063/5.0049793 ◽

2021 ◽

Vol 129 (17) ◽

pp. 175302

Author(s):

Dengke Ma ◽

Yunshan Zhao ◽

Lifa Zhang

Keyword(s):

Thermal Transport ◽

Graded Interlayer

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The Role of Pressure Fluctuations in Rapidly Rotating Flow

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.70.2785 ◽

2004 ◽

Vol 70 (699) ◽

pp. 2785-2790

Author(s):

Atsushi MATSUMOTO ◽

Yasutaka NAGANO

Keyword(s):

Pressure Fluctuations ◽

Rotating Flow

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Cardiac baroreflex dysfunction in patients with pulmonary arterial hypertension at rest and during orthostatic stress: Role of the peripheral chemoreflex

Journal of Applied Physiology ◽

10.1152/japplphysiol.00152.2021 ◽

2021 ◽

Author(s):

Marcelle Paula-Ribeiro ◽

Indyanara C. Ribeiro ◽

Liliane C. Aranda ◽

Talita M. Silva ◽

Camila M. Costa ◽

...

Keyword(s):

Blood Pressure ◽

Pulmonary Arterial Hypertension ◽

Arterial Hypertension ◽

Early Stage ◽

Pressure Fluctuations ◽

Sit To Stand ◽

Peak Aerobic Capacity ◽

Pulmonary Arterial ◽

Peripheral Chemoreflex

The baroreflex integrity in early-stage pulmonary arterial hypertension (PAH) remains uninvestigated. A potential baroreflex impairment could be functionally relevant and possibly mediated by enhanced peripheral chemoreflex activity. Thus, we investigated 1) the cardiac baroreflex in non-hypoxemic PAH; 2) the association between baroreflex indexes and peak aerobic capacity (i.e., V̇O2peak); and 3) the peripheral chemoreflex contribution to the cardiac baroreflex. Nineteen patients and 13 age- and sex-matched healthy adults (HA) randomly inhaled either 100% O2 (peripheral chemoreceptors inhibition) or 21% O2 (control session), while at rest and during a repeated sit-to-stand maneuver. Beat-by-beat analysis of R-R intervals and systolic blood pressure provided indexes of cardiac baroreflex sensitivity (cBRS) and effectiveness (cBEI). The PAH group had lower cBEIALL at rest (mean ± SD: PAH = 0.5 ± 0.2 vs HA = 0.7 ± 0.1 a.u., P = 0.02) and lower cBRSALL (PAH = 6.8 ± 7.0 vs HA = 9.7 ± 5.0 ms mmHg-1, P < 0.01) and cBEIALL (PAH = 0.4 ± 0.2 vs HA= 0.6 ± 0.1 a.u., P < 0.01) during the sit-to-stand maneuver versus the HA group. The cBEI during the sit-to-stand maneuver was independently correlated to V̇O2peak (partial r = 0.45, P < 0.01). Hyperoxia increased cBRS and cBEI similarly in both groups at rest and during the sit-to-stand maneuver. Therefore, cardiac baroreflex dysfunction was observed under spontaneous and, most notably, provoked blood pressure fluctuations in non-hypoxemic PAH, was not influenced by the peripheral chemoreflex, and was associated with lower V̇O2peak suggesting it could be functionally relevant.

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Grain-Size-Dependent Thermal Transport Properties in Nanocrystalline Yttria-Stabilized Zirconia

MRS Proceedings ◽

10.1557/proc-703-v4.7 ◽

2001 ◽

Vol 703 ◽

Cited By ~ 3

Author(s):

Ho-Soon Yang ◽

J.A. Eastman ◽

L.J. Thompson ◽

G.-R. Bai

Keyword(s):

Grain Boundaries ◽

Thermal Transport ◽

Chemical Vapor ◽

Yttria Stabilized Zirconia ◽

Organic Chemical ◽

Stabilized Zirconia ◽

Size Dependent ◽

Metal Organic ◽

Organic Chemical Vapor Deposition

ABSTRACTUnderstanding the role of grain boundaries in controlling heat flow is critical to the success of many envisioned applications of nanocrystalline materials. This study focuses on the effect of grain boundaries on thermal transport behavior in nanocrystalline yttria-stabilized zirconia (YSZ) coatings prepared by metal-organic chemical vapor deposition.

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Comparison of Mixture and Multifluid Models for In-Nozzle Cavitation Prediction

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4026369 ◽

2014 ◽

Vol 136 (6) ◽

Cited By ~ 32

Author(s):

Michele Battistoni ◽

Sibendu Som ◽

Douglas E. Longman

Keyword(s):

Mixture Model ◽

Bubble Dynamics ◽

National Laboratory ◽

Pressure Fluctuations ◽

Argonne National Laboratory ◽

Numerical Approach ◽

Fuel Injectors ◽

Cavitation Inception ◽

Noncondensable Gases ◽

Large Pressure

Fuel injectors often feature cavitation because of large pressure gradients, which in some regions lead to extremely low pressures. The main objective of this work is to compare the prediction capabilities of two multiphase flow approaches for modeling cavitation in small nozzles, like those used in high-pressure diesel or gasoline fuel injectors. Numerical results are assessed against quantitative high resolution experimental data collected at Argonne National Laboratory using synchrotron X-ray radiography of a model nozzle. One numerical approach uses a homogeneous mixture model with the volume of fluid (VOF) method, in which phase change is modeled via the homogeneous relaxation model (HRM). The second approach is based on the multifluid nonhomogeneous model and uses the Rayleigh bubble-dynamics model to account for cavitation. Both models include three components, i.e., liquid, vapor, and air, and the flow is compressible. Quantitatively, the amount of void predicted by the multifluid model is in good agreement with measurements, while the mixture model overpredicts the values. Qualitatively, void regions look similar and compare well with the experimental measurements. Grid converged results have been achieved for the prediction of mass flow rate while grid-convergence for void fraction is still an open point. Simulation results indicate that most of the vapor is produced at the nozzle entrance. In addition, downstream along the centerline, void due to expansion of noncondensable gases has been identified. The paper also includes a discussion about the effect of turbulent pressure fluctuations on cavitation inception.

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The role of optical phonons in intermediate layer-mediated thermal transport across solid interfaces

Physical Chemistry Chemical Physics ◽

10.1039/c7cp02982a ◽

2017 ◽

Vol 19 (28) ◽

pp. 18407-18415 ◽

Cited By ~ 11

Author(s):

Eungkyu Lee ◽

Tengfei Luo

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulation ◽

Optical Phonon ◽

Thermal Transport ◽

Intermediate Layer ◽

Dynamics Simulation ◽

Optical Phonons ◽

Spectral Matching

A study with molecular dynamics simulation shows that optical phonon vibrational spectral matching by an intermediate layer can significantly impact thermal transport across diatomic solid interfaces.

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