Mechanics-based design of lithium-ion batteries: a perspective.

From the overall framework of battery development, the battery structures have not received enough attention compared to the chemical components in batteries. The mechanical-electrochemical coupling behavior is a starting point for investigation on battery structures and the subsequent battery design. This perspective systematically reviews the efforts on the mechanics-based design for lithium-ion batteries (LIBs).

Experimental measurement of electro-chemo-mechanical properties of a composite silicon electrode in lithium ion batteries.

The applications of silicon (Si)-based electrodes in lithium ion batteries have been impeded by mechanical degradation caused by lithiation/delithiation-induced volume changes. Understanding the evolution of mechanical behavior and properties of Si composite electrodes during electrochemical cycling is indispensable to develop coping strategies and predict battery life. In this study, we optimized an method for measuring electro-chemo-mechanical properties, including partial molar volume, elastic modulus, and electrochemical reaction-induced stress, based on the curvature changes of cantilever electrodes.

Near-infrared-laser-navigated dancing bubble within water via a thermally conductive interface.

Precise manipulation of droplets or bubbles hosts a broad range of applications for microfluidic devices, drug delivery, and soft robotics. Generally the existing approaches via passively designing structured surfaces or actively applying external stimuli, inherently confine their motions within the planar or curved geometry at a slow speed. Consequently the realization of 3D manipulation, such as of the underwater bubbles, remains challenging.

Snap-through of graphene nanowrinkles under out-of-plane compression.

Nanowrinkles (i.e. the buckled nanoribbons) are widely observed in nano-devices assembled by two-dimensional (2D) materials.

Elucidating the Role of Rational Separator Microstructures in Guiding Dendrite Growth and Reviving Dead Li.

Li metal has attracted considerable attention as the preferred anode material for high-energy batteries. However, Li dendrites have limited the development of Li-metal batteries. Herein, the effects of tuning the porous separator microstructure (SM) for guiding Li dendrite growth and reviving dead Li are revealed using a mechano-electrochemical phase-field model.

The effect of re-directed patient flow in combination with targeted infection control measures on the spread of multi-drug-resistant Enterobacteriaceae in the German health-care system: a mathematical modelling approach.

Objective: The introduction of multi-drug-resistant Enterobacteriaceae (MDR-E) by colonized patients transferred from high-prevalence countries has led to several large outbreaks of MDR-E in low-prevalence countries, with the risk of propagated spread to the community. The goal of this study was to derive a strategy to counteract the spread of MDR-E at the regional health-care network level.

Methods: We used a hybrid ordinary differential equation and network model built based on German health insurance data to evaluate whether the re-direction of patient flow in combination with targeted infection control measures can counteract the spread of MDR-E in the German health-care system.

Gas permeation through nanoporous single-walled carbon nanotubes: the confinement effect.

The gas permeation through nanoscale membranes like graphene has been extensively studied by experiments and empirical models. In contrast to planar membranes, the single-walled carbon nanotube has a natural confined hollow structure, which shall affect the gas permeation process. We perform molecular dynamics simulations to investigate the effect of the nanotube diameter on the gas permeation process.

Random walks with asymmetric time delays.

It is usually expected that time delays cause oscillations in dynamical systems-there might appear cycles around stationary points. Here we study random walks with asymmetric time delays. In our models, the probability of a walker to move to the right or to the left depends on the difference between two state-dependent fitness functions evaluated at two different times.

Thermal transport in porous graphene with coupling effect of nanopore shape and defect concentration.

Thermal conductivity of porous graphene can be affected by defect concentration, nanopore shape and distribution, and it is hard to clarify the effects due to the correlation of those factors. In this work, molecular dynamics simulation is used to compare the thermal conductivity of graphene with three shapes of regularly arranged nanopores. The results prove the dominant role of defect concentration under certain circumstances in reducing thermal conductivity, while the coupling effect of nanopore shape should be noticed.

Interaction of rod decussation and crack growth in enamel.

Enamel possesses ingenious hierarchical structure that gives rise to superior fracture resistance. Despite considerable efforts devoted to characterization of fracture behavior of enamel, the role of rod decussation in fracture of enamel is largely unknown. In this study, the features of rod decussation in the inner enamel are experimentally identified, and analyses of crack growth in enamel are carried out using a micromechanical model of enamel, in which the structural features of the outer enamel and rod decussation of the inner enamel are incorporated.

Deformation of Copper Nanowire under Coupled Tension-Torsion Loading.

Metallic nanowires (NWs) are essential building blocks for flexible electronics, and experience different deformation modes due to external mechanical loading. Using atomistic simulations, this work investigated the deformation behavior of copper nanowire under coupled tension-torsion loading. A transition in both yielding pattern and dislocation pattern were observed with varying torsion/tension strain ratios.

Radial Flow Field of Spiral Cochlea and Its Effect on Stereocilia.

The opening of the ion channels ultimately depends on the movement and energy conversion of the microstructural organization. But the role was not yet clear how the active sound amplification function is generated by the microstructure in the cochlear characteristic spiral shape. In this paper, an analytical model of the spiral cochlea is developed to investigate the radial flow field generated by the spiral shape of the cochlea and its effect on the outer hair cell stereocilia, and to analyze the effect of the spiral shape on the micromechanics of the cochlea.

Positivity-preserving high-order compact difference method for the Keller-Segel chemotaxis model.

The paper is concerned with development of an accurate and effective positivity-preserving high-order compact difference method for solving the Keller-Segel chemotaxis model, which is a kind of nonlinear parabolic-parabolic system in mathematical biology. Firstly, a stiffly-stable five-step fourth-order fully implicit compact difference scheme is proposed. The new scheme not only has fourth-order accuracy in the spatial direction, but also has fourth-order accuracy in the temporal direction, and the computational strategy for the nonlinear chemotaxis term is provided.

Modulation of turbulent Rayleigh-Bénard convection under spatially harmonic heating.

We numerically study turbulent Rayleigh-Bénard (RB) convection under spatial temperature modulation, where the bottom temperature varies sinusoidally around a mean value in space. Both two- and three-dimensional simulations are performed over the Rayleigh number range 10^{7}≤Ra≤10^{10} and the wave number range 1≤k≤120 at fixed Prandtl number Pr=0.7.

The Effect of Endolymphatic Hydrops and Mannitol Dehydration Treatment on Guinea Pigs.

Background: Endolymphatic hydrops (EH) is considered as the pathological correlate of Menière's disease (MD) and cause of hearing loss. The mechanism of EH, remaining unrevealed, poses challenges for formalized clinical trials.

Objective: This study aims to investigate the development of hearing loss, as well as the effect of dehydration treatment on EH animal models.

The effect of layer number on the gas permeation through nanopores within few-layer graphene.

Few-layer graphene has been widely regarded as an efficient filter for gas separation, but the effect of the layer number on the gas permeation process is still unclear. To explore the layer number effect, we perform molecular dynamics simulations to investigate the gas permeation through a nanopore within the few-layer graphene. Our numerical simulations show that the permeation constant decreases with increasing layer number, which is analyzed based on the macroscopic Kennard empirical model.

Modulation of DNA conformation in electrolytic nanodroplets.

The behavior of deoxyribonucleic acid (DNA) molecules in confinement is of profound importance in various bioengineering and medical applications. In the present study, all-atom molecular dynamics simulation is utilized to investigate the transition of the double-strand DNA (dsDNA) conformation in the electrolytic nanodroplet. Three typical conformations, , , , and , are observed for different droplet sizes and ionic concentrations.

Temperature Dependence of Interfacial Bonding and Configuration Transition in Graphene/Hexagonal Boron Nitride Containing Grain Boundaries and Functional Groups.

The quasi-three-dimensional effect induced by functional groups (FGo) and the in-plane stress and structural deformation induced by grain boundaries (GBs) may produce more novel physical effects. These physical effects are particularly significant in high-temperature environments and are different from the behavior in bulk materials, so its physical mechanism is worth exploring. Considering the external field (strain and temperature field), the internal field (FGo and GBs) and the effect of distance between FGs and GBs on the bonding energy, configuration transition, and stress distribution of graphene/h-BN with FGo and GBs (GrO-BN-GBs) in the interface region were studied by molecular dynamics (MD).

Effects of lesions of the organ of corti on hearing.

Background: Lesions causing changes in the microstructure of the organ of Corti may lead to hearing impairment.

Aims/objectives: The aim of this study was to investigate the effect of various structural lesions on the organ of Corti and the auditory function.

Methods: A finite element method of the cochlea and the organ of Corti were established based on computed tomography scanning and anatomical data.

Diffusion-Induced Stress in Commercial Graphite Electrodes during Multiple Cycles Measured by an In Situ Method.

The cyclic stress evolution induced by repeated volume variation causes mechanical degradation and damage to electrodes, resulting in reduced performance and lifetime of LIBs. To probe the electro-chemo-mechanical coupled degradation, we conducted in situ measurements of Young's modulus and stress evolution of commercial used graphite electrodes during multiple cycles. A bilayer graphite electrode cantilever is cycled galvanostatically in a custom cell, while the bending deformation of the bilayer electrode is captured by a CCD optical system.

A non-standard discretized SIS model of epidemics.

In this paper we introduce and analyze a non-standard discretized SIS epidemic model for a homogeneous population. The presented model is a discrete version of the continuous model known from literature and used by us for building a model for a heterogeneous population. Firstly, we discuss basic properties of the discrete system.

Mesoscale Simulation-Based Parametric Study of Damage Potential in Brain Tissue Using Hyperelastic and Internal State Variable Models.

Two-dimensional mesoscale finite element analysis (FEA) of a multilayered brain tissue was performed to calculate the damage-related average stress triaxiality and local maximum von Mises strain in the brain. The FEA was integrated with rate-dependent hyperelastic and internal state variable (ISV) models, respectively, describing the behaviors of wet and dry brain tissues. Using the finite element results, a statistical method of design of experiments (DOE) was utilized to independently screen the relative influences of seven parameters related to brain morphology (sulcal width/depth, gray matter (GM) thickness, cerebrospinal fluid (CSF) thickness and brain lobe) and loading/environment conditions (strain rate and humidity) with respect to the potential damage growth/coalescence in the brain tissue.

Effect of misfit strain on the thermal expansion coefficient of graphene/MoS van der Waals heterostructures.

Because of their advanced properties inherited from their constituent atomic layers, van der Waals heterostructures such as graphene/MoS are promising candidates for many optical and electronic applications. However, because heat tends to be generated during the operation of nanodevices, thermal expansion is an important phenomenon to consider for the thermal stability of such heterostructures. In the present work, molecular dynamics simulations are used to investigate the thermal expansion coefficient of the graphene/MoS heterostructure, and how the unavoidable misfit strain affects that coefficient is revealed.

One-dimensional transition metal dichalcogenide lateral heterostructures.

Forming heterostructures is a well-established technique to utilize different constituent materials to achieve novel properties like efficient light emission and high-quality electron tunneling. Recent experiments have successfully synthesized one-dimensional van der Waals heterostructures and have discovered plenty of superior properties benefiting from the dimension reduction. Inspired by the success of the van der Waals counterparts, we propose a one-dimensional lateral heterostructure based on transition metal dichalcogenide nanotubes.