Cage effect for the velocity correlation functions of a Brownian particle in viscoelastic shear flows.

Phys Rev E Stat Nonlin Soft Matter Phys

Institute of Mathematics and Natural Sciences, Tallinn University, 29 Narva Road, 10120 Tallinn, Estonia.

Published: October 2014

The long-time limit behavior of velocity correlation functions (VCFs) for an underdamped Brownian particle in an oscillatory viscoelastic shear flow is investigated using the generalized Langevin equation with a power-law memory kernel. The influence of a fluctuating environment is modeled by an additive external fractional Gaussian noise. The exact expressions of the correlation functions of the fluctuating components of velocity for the Brownian particle in the shear plane have been calculated. Also, the particle's angular momentum is found. It is shown that in a certain region of the system parameters an interplay of the shear flow, memory effects, and external noise can induce a bounded long-time behavior of the VCFs, even in the shear flow direction, where in the case of internal noise the velocity process is subdiffusive, i.e., unbounded in time. Moreover, we find resonant behavior of the VCFs and the angular momentum versus the shear oscillation frequency, implying that they can be efficiently excited by oscillatory shear. The role of the initial positional distribution of particles is also discussed.

Download full-text PDF

Source
http://dx.doi.org/10.1103/PhysRevE.90.042127DOI Listing

Publication Analysis

Top Keywords

correlation functions
12
brownian particle
12
shear flow
12
velocity correlation
8
viscoelastic shear
8
angular momentum
8
behavior vcfs
8
shear
7
cage velocity
4
functions brownian
4

Similar Publications

Introduction: Standing balance is essential for physical functioning. Therefore, improving balance control is a key priority in the management of knee osteoarthritis (OA), underscoring the importance of accurately assessing standing balance.

Purpose: To assess reliability, construct validity and responsiveness of common clinical balance tests, including Step Test, Single-Leg Stance Test, and Functional Reach Test, in patients with knee OA.

View Article and Find Full Text PDF

The amorphous/crystalline (A/C) assembly in molecular solids has a direct bearing on their attributes and applications, including mechanical, pharmaceutical, electronic and photophysical.  A systematic analysis of the molecular features and interactions that determine the predilection towards the A, C or bi-stable A-C states is critical.  This fundamental problem is addressed through an exhaustive investigation of a large family of alkoxyalkyl diaminodicyanoquinodimethanes (ROR'-DADQs); enhancement of their fluorescence from the solution, to the A, to the C state serves as an excellent signature of the phase preference and temporal stability.

View Article and Find Full Text PDF

White Matter Fiber Bundle Alterations Correlate with Gait and Cognitive Impairments in Parkinson's Disease based on HARDI Data.

Curr Med Imaging

January 2025

Department of Radiology, Beijing Friendship Hospital, Capital Medical University, No. 95, Yong An Road, Xicheng District, Beijing 100050, China.

Background: The neuroanatomical basis of white matter fiber tracts in gait impairments in individuals suffering from Parkinson's Disease (PD) is unclear.

Methods: Twenty-four individuals living with PD and 29 Healthy Controls (HCs) were included. For each participant, two-shell High Angular Resolution Diffusion Imaging (HARDI) and high-resolution 3D structural images were acquired using the 3T MRI.

View Article and Find Full Text PDF

Generalized Hartree-Fock (GHF) is a long-established electronic structure method that can lower the energy (compared to spin-restricted variants) by breaking physical wave function symmetries, namely and . After an exposition of GHF theory, we assess the use of GHF trial wave functions in phaseless auxiliary field quantum Monte Carlo (ph-AFQMC-G) calculations of strongly correlated molecular systems including symmetrically stretched hydrogen rings, carbon dioxide, and dioxygen. Imaginary time propagation is able to restore symmetry and yields energies of comparable or better accuracy than CCSD(T) with unrestricted HF and GHF references, and consistently smooth dissociation curves─a remarkable result given the relative scalability of ph-AFQMC-G to larger system sizes.

View Article and Find Full Text PDF

Background: The progression of diabetic kidney disease (DKD) affects the patient's kidney glomeruli and tubules, whose normal functioning is essential for maintaining normal calcium (Ca) and phosphorus (P) metabolism in the body. The risk of developing osteoporosis (OP) in patients with DKD increases with the aggravation of the disease, including a higher risk of fractures, which not only affects the quality of life of patients but also increases the risk of death.

Aim: To analyze the risk factors for the development of OP in patients with DKD and their correlation with Ca-P metabolic indices, fibroblast growth factor 23 (FGF23), and Klotho.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!