Nonlocal Effects Research Articles

A comparative study of temperature-dependent characteristics and non-local behavior in a submerged microstretch thermoelastic medium using two models

This article is concerned with a thermoelastic response in a non-local micro-stretch completely covered in the endless non-viscous fluid under temperature dependent, the medium is investigated employing the theory of Green-Naghdi (G-N III) and the model of three-phase-lag (3PHL).Basic equations are derived based on these models. The normal mode technique is employed to achieve an analysis solution to the problem. The study used a magnesium crystal element to compare non-local measurements of thermo-micro-stretch elasticity in water using the (G-N III) theory and the (3PHL) model. The non-local effect has been discovered to have a considerable impact on all physical quantities. Furthermore, comparisons are made between three different frequency values.

Study on non-local effects in asymmetric overlapping nanowires

Abstract The nonlocal effects in asymmetric overlapping nanowires are studied. The new phenomena on a very small scale is found. When the scale is reduced to about 0.1nm, the frequency corresponding to the peak at first redshift and then blueshift, or vice versa. This new phenomena may relate to the degree of overlapping between the two nanowires. In other words, when the geometry is close to the limit, namely kissing nanowires, a little change in parameters will produce new phenomena.

Buckling analysis of single‐walled carbon nanotubes using the initial value method and approximate transfer matrix based on nonlocal elasticity theory

AbstractIn this study, a novel method is presented to analyze the buckling behavior of single‐walled carbon nanotubes (SWCNTs) using the initial value method (IVM) in conjunction with the approximate transfer matrix, within the framework of nonlocal elasticity theory. The study aims to accurately approximate critical buckling load parameters under various boundary conditions, without encountering high computational requirements. IVM enables the computation of displacements and stress resultants along the entire beam from given initial conditions. The approximate transfer matrix is employed to analyze system states at different points through successive integration of solutions, generating the principal matrix needed for IVM and ensuring systematic and precise results that optimize the accuracy of the analysis. A convergence study confirms the effectiveness and precision of the proposed method, revealing a decrease in the critical buckling load parameters as the nonlocal parameter increases, applicable across all boundary conditions studied (simply supported, clamped–clamped, clamped–simply supported, and clamped‐free). These results underscore the need to incorporate nonlocal effects for more accurate nanostructure mechanics predictions. The integration of IVM and the approximate transfer matrix provides a computationally efficient alternative to traditional numerical and semi‐analytical methods, aiding researchers and engineers working with SWCNTs and other nanomaterials.

Non-locality and spillover effects of residential flood damage on community recovery: Insights from high-resolution flood claim and mobility data

Examining the relationship between vulnerability of the built environment and community recovery is crucial for understanding disaster resilience. Yet, this relationship is rather neglected in the existing literature due to limitations in the availability of empirical datasets needed for such analysis. In this study, we combined fine-resolution flood damage claim data (composed of both insured and uninsured losses) and human mobility data (composed of millions of movement trajectories) during the 2017 Hurricane Harvey in Harris County, Texas, to specify the extent to which vulnerability of the built environment (i.e., residential flood damage) affects community recovery (based on the speed of human mobility recovery) locally and regionally. We examined such relationship using spatial lag, spatial reach, and spatial decay models to measure the extent of spillover effects of residential flood damage on community recovery. The results indicate that: first, the severity of residential flood damage significantly affects the speed of community recovery. A greater extent of residential flood damage suppresses community recovery not only locally but also in the surrounding areas; second, the spillover effects of residential flood damage on community recovery decay with distance from the highly damaged areas with a spatial reach of up to 31.2 miles (49.92 Km); third, areas display heterogeneous spatial decay coefficients, which are associated with urban form and structure features such as the density of facilities and roads. These findings provide a novel data-driven characterization of the spatial spillover effects of residential flood damage on community recovery and move us closer to a better understanding of complex spatial diffusion processes that shape community resilience to hazards. This study also provides valuable insights for emergency managers and public officials seeking to mitigate the non-local effects of flood damage.

Faedo-Galerkin method for the time-fractional reaction-diffusion model

This paper investigates a time-fractional reaction-diffusion equation characterized by a Caputo derivative of fractional order , incorporates non-local and memory effects that are essential for accurately modeling complex diffusion processes in such environments. These effects arise from the fractal nature of the media, which leads to anomalous diffusion behavior that cannot be adequately described by classical diffusion models. We start by giving a definition of a weak solution for this problem, ensuring that the solution satisfies the equation in a generalized sense. Subsequently, the Faedo-Galerkin method combined with compactness arguments is employed to establish the existence and uniqueness of the weak solution. This approach involves approximating the solution using a sequence of finite-dimensional functions and then passing to the limit to obtain the desired solution . Moreover, we establish the stability of these solutions, which is fundamental for understanding their behavior under varying conditions and ensuring the reliability of the model . Our findings contribute to a deeper understanding of anomalous diffusion phenomena in fractal media and provide a solid foundation for further research in this area.

Nonlocal buckling analysis of double-walled carbon nanotubes using initial value method and matricant approach

In this study, the buckling behavior of double-walled carbon nanotubes (DWCNTs) is investigated using the initial value method (IVM) combined with the approximate transfer matrix (ATM) approach within the framework of nonlocal elasticity theory. The aim is to provide a method that best estimates the critical buckling loads with improved accuracy and computational efficiency. To validate the method, the critical buckling loads obtained without considering nonlocal effects were compared with results from the literature, showing a high degree of agreement. Various boundary conditions, including simply supported (S-S), clamped-simply supported (C-S), clamped-free (C-F), and clamped-clamped (C-C), have been considered for investigation. The effects of nonlocal parameters, aspect ratios, and boundary conditions on the critical buckling loads are analyzed. The findings emphasize the importance of accounting for these parameters in mechanical analyses to ensure accurate predictions. The proposed framework provides an efficient alternative to existing numerical methods and offers valuable benchmarks for future research on the mechanical behavior of nanostructures.

Capturing the nonlocal effect using a novel hybrid 8-node plate element based on the Hellinger–Reissner variational principle

Capturing the nonlocal effect using a novel hybrid 8-node plate element based on the Hellinger–Reissner variational principle

Low cloud-SST variability over the summertime subtropical Northeast Pacific: Role of extratropical atmospheric modes

Abstract Over the subtropical Northeast Pacific (NEP), highly reflective low clouds interact with underlying sea-surface temperature (SST) to constitute a local positive feedback. Recent modeling studies showed that, together with wind-evaporation-SST (WES) feedback, the summertime low cloud-SST feedback promotes nonlocal trade wind variations, modulating subsequent evolution of El Niño-Southern Oscillation (ENSO). This study aims to identify drivers of summertime low-cloud variations, using satellite observations and global atmosphere model simulations forced with observed SST. A trans-basin teleconnection is identified, where the North Tropical Atlantic (NTA) warming induced by the North Atlantic Oscillation (NAO) increases precipitation, exciting warm Rossby waves that extend into the NEP. The resultant enhancement of static stability promotes summertime low cloud-SST variability. By regressing out the effects of the preceding ENSO and NTA SST, atmospheric internal variability over the extratropical North Pacific, including the North Pacific Oscillation (NPO), is found to drive the NEP cooling by latent heat loss and subsequent summer low cloud-SST variability. With the help of the background trade winds and WES feedback, the SST anomalies extend southwestward from the low-cloud region, accompanied by ENSO in the following winter. This suggests the nonlocal effects of low clouds identified by recent studies. Analysis of a 500-year climate model simulation corroborates the NTA and NPO forcing of NEP low cloud-SST variability and subsequent ENSO.

What if string theory has a de Sitter excited state?

We propose precise effective field theory criteria to obtain a four-dimensional de Sitter space within M-theory. To this effect, starting with the state space described by the action of metric perturbations, fluxes etc over the supersymmetric Minkowski vacuum in eleven-dimensions, we discuss the most general low energy effective action in terms of the eleven-dimensional fields including non-perturbative and non-local terms. Given this, our criteria to obtain a valid four-dimensional de Sitter solution at far IR involve satisfying the Schwinger-Dyson equations of the associated path integral, as well as obeying positivity constraints on the dual IIA string coupling and its time derivative. For excited states, the Schwinger-Dyson equations imply an effective emergent potential different from the original potential. We show that while vacuum solutions and arbitrary coherent states fail to satisfy these criteria, a specific class of excited states called the Glauber-Sudarshan states obey them. Using the resurgent structure of observables computed using the path integral over the Glauber-Sudarshan states, four-dimensional de Sitter in the flat slicing can be constructed using a Glauber-Sudarshan state in M-theory.Among other novel results, we discuss the smallness of the positive cosmological constant, including the curious case where the cosmological constant is very slowly varying with time. We also discuss the resolution of identity with the Glauber-Sudarshan states, generation and the convergence properties of the non-perturbative and the non-local effects, the problems with the static patch and other related topics. We analyze briefly the issues related to the compatibility of the Wilsonian effective action with Borel resummations and discuss how they influence the effective field theory description in a four-dimensional de Sitter space.

Broadband acoustic metamaterial absorber

Constrained by the causality nature, it is a challenge to achieve low-frequency broadband efficient absorption via passive materials. By coupling local resonances as many as possible, broadband metamaterial absorbers can be realized. In this scenario, the coupling effect is crucial for improving the absorption efficiency. Here, we demonstrate a kind of acoustic metamaterial absorber capable of high-efficiency broadband absorption by optimizing the non-local coupling effect. Cascade neck-embedded Helmholtz resonator is designed as the subunit of the metamaterial absorber. By coupling 36 subunits, a metamaterial absorber is constructed with the aid of optimization algorithm. The simulation results suggest that strong non-locality is induced in the near field, which effectively suppresses the impedance oscillations and absorption dips at the antiresonance frequencies. Eventually, the presented metamaterial absorber realizes impedance matching to the air from 320 Hz to 6400 Hz, leading to efficient broadband absorption performance. The results and methodologies in this work reveal the significance of non-local coupling effect in coupled-resonant metamaterials.

Multiregion Light Control in Diffusive Media via Wavefront Shaping.

Wavefront shaping allows focusing light through or inside strongly scattering media, but the background intensity also increases which reduces the target's contrast. By combining transmission or deposition matrices for different regions, we construct joint operators to achieve spatially resolved control of light in diffusive systems. The eigenmode of a contrast operator can maximize the power contrast between a target and its surrounding. A difference operator enhances the power delivery to a target while avoiding the background increase. This work opens the door to coherent control of nonlocal effects in wave transport for practical applications.

Buckling analysis of nanoscale beams based on nonlocal Timoshenko beam theory

Abstract Eigen-buckling problems of nanoscale beams continue to be of great research interest, and the nonlocal theory is widely used. However, the existing research generally adopted some simplified assumptions of nonlocal effects. This article studies the buckling behaviors of the nonlocal Timoshenko beam, where the nonlocal effects are considered both on the governing equations and boundary conditions. The variational principle is adopted to obtain the nonlocal governing equations and boundary conditions. The buckling solutions for nanoscale beams are obtained analytically. Numerical comparisons validate the correctness of the present results. Parameter study shows that the buckling characteristic of nonlocal beams is different from that of classical beams, and the nonlocal effect is dependent on boundary conditions and geometry size of nanoscale beams.

Acute local and non-local morphological, sensory and fluid responses to stretching and foam rolling in young females

BackgroundThis study aimed to compare and examine the local and non-local effects of a foam rolling (FR) and static stretching (SS) intervention applied to the plantar flexor (PF). MethodsFourteen female participants were investigated. Each participant underwent three conditions in a random order at least 48h apart and at the same time of the day: Control (CC), SS, and FR. Each condition was performed unilaterally in the dominant PF for 4 sets (apart from CC). SS was performed for 30 s. The FR included 30 rolls (15 in each direction) over a period of 30 s. A rest of 30 s was provided between each set for all conditions. Outcome variables were ankle dorsiflexion range of movement (ROM), tissue hardness, localized bioimpedance analysis at 50 kHz (L-BIA), and pain pressure thresholds (PPT). Tissue hardness, L-BIA, and PPT were measured in the lower leg and thigh. Measures were assessed pre (T0), immediately post (T1), and 10-min after (T2) the intervention. ResultsNo differences were found for time for the CC or between the T0 of each condition. Concerning the lower leg, ROM improved for SS and FR from T0 to T1 while returning to baseline in T2. A significant increase in PPT was observed only for SS in T1. L-BIA showed a significant increase for both phase angle and impedance only for FR in T1. Tissue hardness did not change for any group at any time-point. Concerning the thigh, no measure at any time point showed significant differences. ConclusionBoth, FR and SS were able to acutely improve ankle ROM. The observed changes were probably caused by a change in viscoelastic properties and local pain perception, without any variation in tissue morphology. FR was the only intervention to improve the intracellular-to-extracellular ratio and decrease fluids. Non-local effects were not observed.

Role of Nonlocal Electrostatic Effects in the Stabilization of Monovalent Cations in an Aqueous Cavity Surrounded by a Weakly Polar Environment

Role of Nonlocal Electrostatic Effects in the Stabilization of Monovalent Cations in an Aqueous Cavity Surrounded by a Weakly Polar Environment

Verification of the kinetic electron role in the microinstabilities in a negative triangularity model equilibrium

Effect of kinetic electrons on negative triangularity plasmas has been investigated and compared against the corresponding positive triangularity plasmas, using the global gyrokinetic code X-point Gyrokinetic Code with scale-separated delta-f option without Coulomb collisions. Our model magnetic equilibria have strong positive and negative triangularities and weak magnetic shear. However, unusually large ρi/a and low density plasmas are chosen to maximize the nonlocal effect to investigate the finite ρi effect and to be clearly away from kinetic ballooning modes. Similar conclusions to previous flux tube and global simulations have been obtained in this highly nonlocal model plasma: it is essential to include kinetic electrons in the micro-instability study of negative triangularity plasmas. Most physics findings agree with existing reports, with some disagreement. We offer a new “effective trapping fraction” concept that can add to the explanation of the growth rate difference between NT and PT plasmas, pointing to the significant variation in trapped particle fractions that have turning points in the mode growth regions.

The instant probability of object with deterministic motion. Another way to understand quantum mechanics

Usually, the idea of probability is applied only to the random motion in physics. Here, the instant probability concept is obtained by applying the probability approach to objects with deterministic motion trajectories via a coin falling to the ground as an example. Applied this concept to understand quantum mechanics, the following conclusions are inferred: The wave function/quantum state represents an instant probability distribution of physical quantities after taking into account Planck's constant; the collapse of the wave function is a special case of any function on time-dependent probability prediction has to collapse when performing measurement. The arrangement of measurements will affect the observed results; Quantum mechanics reveals the existence of non-local effects, which have nothing to do with the interaction in classical physics. Quantum mechanics cannot answer questions such as whether the cat is dead or alive before opening the box. The correct answer to this kind of question has to be from classic physics.

Accurate and efficient analytical simulation of free vibration for embedded nonlocal CNTRC beams with general boundary conditions

This study aims to evaluate the free vibrational response of embedded restrained nanobeams enriched by nanocomposites based on an exact Fourier series approach. In order to capture the small-scale effects on the dynamical response, Eringen's differential form of nonlocal elasticity is used which employs a scale (nonlocal) parameter. Within the framework of Rayleigh and Bernoulli-Euler beam theories, including the effect of nonlocality and employing the Fourier sine series together with Stokes' transformation, systems of linear equations are obtained and solved using the coefficient matrices. The combined effects of elastic boundary conditions, elastic foundation, dispersion patterns and volume fractions of carbon nanotubes, and nonlocal parameter are examined by solving eigenvalue problems constructed with Fourier infinite series. Free vibration frequencies are calculated for carbon nanotube-reinforced nanobeams under different rigid or restrained boundary conditions, including Winkler-Pasternak type elastic foundation. A comprehensive parametric study is performed, focusing on various effects for the free vibrational response of the composite nanobeam reinforced with carbon nanotubes. It is concluded that adding a small amount of carbon nanotube material can reinforce the stiffness of the composite nanobeam, and its free vibration performance is significantly affected by the distribution patterns, elastic medium, and boundary conditions.

Assessing the Performance of Flux Imbalance Prediction Models Using Large Eddy Simulations Over Heterogeneous Land Surfaces

Accurate representation of heat fluxes is crucial for understanding land–atmosphere interactions and improving atmospheric simulations. However, a common issue arises with flux imbalance, where the measured turbulent heat flux tends to be underestimated due to the nonlocal effects of atmospheric secondary circulations. This study evaluated four flux imbalance prediction models by analyzing data from large eddy simulations performed over heterogeneous land surfaces. For that, a checkerboard pattern of soil moisture was used to define the lower boundary conditions for the atmosphere, across heterogeneity scales ranging from 50 m to 2.4 km. The results show that the selected models can effectively predict flux imbalance when provided with proper semi-empirical factors. The presence of two distinct secondary circulations, thermally-induced mesoscale circulation and turbulent organized structures, account for the nonlinear effect of the heterogeneity scale on the flux imbalance, but it does not affect the performance of the selected models. This study suggests that the flux imbalance prediction models are useful for improving e.g. eddy-covariance measurements. Additionally, a quadrant analysis showed an increasing difference between ejections and sweeps with height, which explains the decrease and increase of the turbulent heat flux and flux imbalance, respectively, and underscores the importance of accounting for vertical variations in turbulent fluxes to represent atmospheric processes accurately.

Local and non-local effects (on the posterior chain) of four weeks of foot exercises: a randomized controlled trial

This study investigated the local, remote, and contralateral effects of a four-week intrinsic foot muscle exercise intervention in recreationally active participants on foot parameters, flexibility, and performance of the posterior chain (PC). Twenty-eight healthy participants (12f, 16m) were randomly assigned to a control group or performed 2 × 6 min of foot exercises twice daily unilaterally at least five days/week for four weeks. At baseline (M1), after the intervention (M2), and after a four-week wash-out period (M3), we assessed bilateral Foot Posture Index-6, medial longitudinal arch mobility, single-leg stance balance, range of motion (ROM) (first metatarsophalangeal joint and ankle), and flexibility and performance of the PC. The FPI-6 score changes over time differed significantly between groups for both legs, improving by 26% in the trained- (p < .001) and 11% in the untrained leg (p = .02) in the intervention group from M1 to M2. Improvements were maintained at M3 for the trained leg (p = .02). Ankle range of motion and balance of the trained leg improved from M1 to M2, yet only became significant at M3 (ROM: p = .02; balance: p = .007). The other parameters did not change significantly. A four-week foot exercise intervention might have local but no remote effects in healthy young adults.German Clinical Trial Register (DRKS00027923) (24/08/2022).

Nonlinear static behaviors of nonlocal nanobeams incorporating longitudinal linear temperature gradient

The elastic parameters and the coefficient of thermal expansion (CTE) of nanomaterials change with temperature. If the elastic modulus, the CTE, and the longitudinal linear temperature gradient are coupled, the longitudinal symmetry of the mechanical properties of nanobeams is broken. However, researchers have not yet to examine how this symmetry breaking affects the mechanical properties of nanobeams. This paper provides a new analysis of the modified thermoelastic beam model established by the nonlocal stress gradient theory. The present analysis incorporates the coupling of the longitudinal linear temperature gradient, elastic modulus, thermal expansion, and scale effect. Afterward, we apply the Galerkin method to explore the buckling, post-buckling, and transverse bending of a (10,10) single-walled carbon nanotube (SWCNT). The results show that the linear temperature gradient induces the breaking of the nanobeam's longitudinal symmetry and then results in the coupling of the symmetrical and antisymmetrical weight functions of the deformations. While the linear temperature gradient marginally affects the symmetry of nanobeams, it significantly raises the buckling temperature and introduces the complexity of the post-buckling and transverse force bending. In addition, the integration of the linear longitudinal temperature gradient, elastic modulus, and nonlocal effect more significantly affects nanobeams' mechanical properties than individual factors.