Browsing by Subject "Homogenization"
Results Per Page
Sort Options
Item Open Access Cellular communication among smooth muscle cells: The role of membrane potential via connexins.(Journal of theoretical biology, 2023-11) Xiao, Chun; Sun, Yishui; Huang, Huaxiong; Yue, Xingye; Song, Zilong; David, Tim; Xu, ShixinCommunication via action potentials among neurons has been extensively studied. However, effective communication without action potentials is ubiquitous in biological systems, yet it has received much less attention in comparison. Multi-cellular communication among smooth muscles is crucial for regulating blood flow, for example. Understanding the mechanism of this non-action potential communication is critical in many cases, like synchronization of cellular activity, under normal and pathological conditions. In this paper, we employ a multi-scale asymptotic method to derive a macroscopic homogenized bidomain model from the microscopic electro-neutral (EN) model. This is achieved by considering different diffusion coefficients and incorporating nonlinear interface conditions. Subsequently, the homogenized macroscopic model is used to investigate communication in multi-cellular tissues. Our computational simulations reveal that the membrane potential of syncytia, formed by interconnected cells via connexins, plays a crucial role in propagating oscillations from one region to another, providing an effective means for fast cellular communication. Statement of Significance: In this study, we investigated cellular communication and ion transport in vascular smooth muscle cells, shedding light on their mechanisms under normal and abnormal conditions. Our research highlights the potential of mathematical models in understanding complex biological systems. We developed effective macroscale electro-neutral bi-domain ion transport models and examined their behavior in response to different stimuli. Our findings revealed the crucial role of connexinmediated membrane potential changes and demonstrated the effectiveness of cellular communication through syncytium membranes. Despite some limitations, our study provides valuable insights into these processes and emphasizes the importance of mathematical modeling in unraveling the complexities of cellular communication and ion transport.Item Open Access HOMOGENIZATION OF A DISCRETE NETWORK MODEL FOR CHEMICAL VAPOR INFILTRATION PROCESS(COMMUNICATIONS IN MATHEMATICAL SCIENCES, 2021) Xiao, C; Xu, S; Yuex, X; Zhang, C; Zhang, CItem Embargo Homogenization of Chemo-Mechanically Active Porous Media Microstructures(2024) Lindqwister, WinstonFrom batteries to bones, rocks to concrete, porous materials are ubiquitous in the natural and engineered environment, yet remain elusive in their characterization. One of the fundamental challenges of studying porous materials comes down to a fundamental question of linking the microscale to the mesoscale. This work addresses two primary linkages for analysis--the chemical response and the mechanical response of the material. Minkowski functionals served as the primary vessel for understanding how material microstructural geometry ties to macroscale energetics. In the case of chemical systems, Minkowski functionals proved to be powerful predictive tools in both reaction steady states and reaction dynamics. These exponential linkage to morphometers serves as a basis for understanding how the interfacial geometry of system affects the non-mixed chemical behavior of said system over time.As a study on novel simulation frameworks for modeling discrete chemical behavior at the microstructural scale, this work also introduces a unique means for modeling interface chemistry--surface CRNs. Surface CRNs are asynchronous cellular automata models similar to Markov chain models. This class of simulator efficiently translates complex chemical behavior into relatively easy-to-follow reaction rules. This class of simulator has proven to be surprisingly accurate despite its simplicity, creating a strong basis for understanding chemical behavior at a discrete level. While one half of this work focused on the ability of Minkowski functionals to predict chemical behavior, the other half of this work focuses on their ability to link to the mechanics of a microstructure. To address the mechanics problem, Minkowski functionals were extracted from 3D x-ray tomographic scans and assessed mechanically via 3D printed and digitally modeled strength assessments. Ultimately, a deep learning model was trained that could accurately predict and recreate the mechanical response profile of a digitally simulated porous microstructure from just four Minkowski functionals. This extended further to 3D printed samples, allowing for the mechanical behavior of physical samples to be predicted just from its geometric descriptors.
Item Open Access Homogenization of thermal-hydro-mass transfer processes(Discrete and Continuous Dynamical Systems - Series S, 2015-02-01) Xu, S; Yue, XIn the repository, multi-physics processes are induced due to the long-time heat-emitting from the nuclear waste, which is modeled as a nonlinear system with oscillating coefficients. In this paper we first derive the homogenized system for the thermal-hydro-mass transfer processes by the technique of two-scale convergence, then present some error estimates for the first order expansions.Item Open Access Homogenization: In mathematics or physics?(Discrete and Continuous Dynamical Systems - Series S, 2016-10-01) Xu, S; Yue, X; Zhang, CIn mathematics, homogenization theory considers the limitations of the sequences of the problems and their solutions when a parameter tends to zero. This parameter is regarded as the ratio of the characteristic size between the micro scale and macro scale. So what is considered is a sequence of problems in axed domain while the characteristic size in micro scale tends to zero. But in the real physics or engineering situations, the micro scale of a medium isxed and can not be changed. In the process of homogenization, it is the size in macro scale which becomes larger and larger and tends to innity. We observe that the homogenization in physics is not equivalent to the homogenization in mathematics up to some simple rescaling. With some direct error estimates, we explain in what sense we can accept the homogenized problem as the limitation of the original real physical problems. As a byproduct, we present some results on the mathematical homogenization of some problems with source term being only weakly compacted in H1, while in standard homogenization theory, the source term is assumed to be at least compacted in H1. A real example is also given to show the validation of our observation and results.