Multiscale Analysis Research Articles

Spatial-social familiarity complements the spatial-social interface: evidence from Yellowstone bison.

Social animals make behavioural decisions based on local habitat and conspecifics, as well as memorized past experience (i.e. 'familiarity') with habitat and conspecifics. Here, we develop a conceptual and empirical understanding of how spatial and social familiarity fit within the spatial-social interface-a novel framework integrating the spatial and social components of animal behaviour. We conducted a multi-scale analysis of the movements of GPS-collared plains bison (Bison bison, n = 66) residing in and around Yellowstone National Park, USA. We found that both spatial and social familiarity mediate how individuals respond to their spatial and social environments. For instance, individuals with high spatial familiarity rely on their own knowledge as opposed to their conspecifics, and individuals with high social familiarity rely more strongly on the movement of conspecifics to guide their own movement. We also found that fine-scale spatial and social phenotypes often scale up to broad-scale phenotypes. For instance, bison that select more strongly to align with their nearest neighbour have larger home ranges. By integrating spatial and social familiarity into the spatial-social interface, we demonstrate the utility of the interface for testing hypotheses, while also highlighting the pervasive importance of cognitive mechanisms in animal behaviour. This article is part of the theme issue 'The spatial-social interface: a theoretical and empirical integration'.

Event‐triggered anti‐disturbance control for switched singular systems based on the uncertainty and disturbance estimator

AbstractThis article studies the event‐triggered anti‐disturbance control problem for switched singular systems (SSSs) based on the uncertainty and disturbance estimator (UDE). First, a composite controller consisting of feedback control and anti‐disturbance control based on UDE is proposed. By constructing the multiple Lyapunov functions and using the average dwell time (ADT) method, sufficient conditions are given to ensure that the closed‐loop system is regular, impulse‐free and globally uniformly asymptotically stable (GUAS). Further, in order to save resources, the event‐triggered control method is introduced into the feedback control, and a novel hybrid event‐triggered mechanism (ETM) is proposed, which guarantees that asynchronous switching and Zeno behavior are excluded. And the solvable conditions in terms of linear matrix inequalities (LMIs) are given. Finally, the validity of the proposed results is verified by the simulations.

Multiscale spatial analysis of two plant–insect interactions: effects of landscape, resource distribution, and other insects

ContextBiotic resource exploitation is a critical determinant of species’ distributions. However, quantifying resource exploitation patterns through space and time can be difficult, complicating their incorporation in spatial ecology studies. Therefore, understanding the local drivers of spatial patterns of resource exploitation may contribute to better large-scale species distribution models.ObjectivesWe investigated (1) how the resource exploitation patterns of two trophic interactions (plant–insect) are explained by insect behaviour, resource aggregation, and potential insect-insect interactions. We also analyzed how (2) resource patch size and (3) resource accessibility in a heterogeneous landscape affected host exploitation patterns.MethodsWe quantified nectar robbing by insects in the genus Bombus (bumblebees) and seed predation by Brachypterolus vestitus larvae (Antirrhinum beetle) on Antirrhinum majus L. (wild snapdragons) in the Pyrenees Mountains, Catalonia, Spain. We tested hypotheses about resource exploitation by integrating spatial analyses at multiple scales.ResultsBoth trophic interactions were aggregated, explained by the aggregation of their resource. At some scales, nectar robbing is more aggregated than the resource. Trophic interaction abundance is proportional to resource patch size, following the ideal free distribution model. Landscape features do not explain the locations exploited. Nectar robbing and seed predation occur together more often than expected.ConclusionsOur findings suggest that multiple biotic and ecological spatial factors may simultaneously affect resource exploitation at a local scale. These findings should be considered when developing agricultural projects, management plans and conservation policies.

Electric–Mechanical coupling analysis of two-dimensional piezoelectric heterogeneous materials in flexible electric devices with extended multiscale isogeometric analysis

Piezoelectric heterogeneous materials are widely used in flexible electronic device design, enhancing sensitivity to external stimuli like pressure and acceleration. Despite their usefulness, analyzing these inherently periodic structures poses significant computational challenges. In response, this paper presents a multiscale isogeometric analysis approach tailored for simulating piezoelectric materials. We introduce an electric–mechanical coupling model using isogeometric analysis (IGA) for two-dimensional piezoelectric membrane structures, assuming the plane stress hypothesis. Our proposed algorithm enables precise calculation of both displacement and electric potential solutions, demonstrating superior convergence properties compared to traditional finite element methods. Furthermore, we extend this approach to multiscale isogeometric analysis for computing numerical solutions in porous structures and heterogeneous composite piezoelectric materials under tensile and bending conditions. Through rigorous numerical testing, we evaluate the proposed extended multiscale isogeometric analysis method, showcasing its efficacy in achieving a balance between computational efficiency and simulation accuracy. This IGA-based electro-mechanical coupling model and numerical algorithm pave the way for more streamlined and precise simulations of piezoelectric materials within the context of flexible electronic devices.

Parametric instability analysis of rotors under anisotropic boundary conditions

Ensuring rotor stability is a major concern in engineering, as instabilities can lead to catastrophic failures. Existing literature shows that anisotropic boundary conditions significantly affect the parametric instability characteristics of rotors under periodical axial loads. However, there is little literature systematically analyzing the formation mechanism of parametric resonance under these boundary conditions or providing a detailed classification of the parametric instability regions. Therefore, this paper presents a comprehensive parametric instability analysis of a rotor subjected to periodic axial loads under anisotropic boundary conditions. A novel approach based on the multiple scales method is proposed to address anisotropy in the boundary conditions. Using this approach, the analytical boundaries of the parametric instability regions are derived, and a proof regarding the absence of certain parametric resonances is presented. These analytical solutions are validated by numerical results obtained from the discrete transition matrix method, which form the basis for systematically investigating the effects of anisotropy in direct or cross-coupling stiffness/damping coefficients on the rotor instability. The key scientific contributions of this work include: Deriving analytical instability boundaries, providing a more efficient alternative to purely numerical methods while maintaining high accuracy; Demonstrating the absence of parametric resonance of difference type under both isotropic or anisotropic boundary conditions; Discovering that anisotropy in stiffness coefficients can induce self-interaction within a given forward or backward whirl mode, as well as interaction between two forward or two backward whirl modes, leading to additional instability regions; Reducing anisotropy in direct damping coefficients may increase critical dynamic load coefficients, potentially enhancing rotor safety; If the cross-coupling stiffness coefficients exceed the threshold for triggering intrinsic instability, the rotor may become unstable in all operating conditions. All these findings offer insights into the stability management of rotors under various operating conditions and provide valuable guidance for designing and operating safer, more efficient rotor systems.

Investigation on combustion instability of electronic fuel injected multi-cylinder radial piston engine through multifractal technique – A comparative analysis

The main objective of the present study was to investigate combustion instability in a multi-cylinder radial piston engine with electronic fuel injection to ensure safety and reliability, maintain fuel efficiency, reduce harmful emissions, which has a positive impact on the environment. Multi-fractal analysis showed that IMEP (mean effective pressure) fluctuations are an anti-persistent process, meaning that there is no correlation between successive events. The return plots showed significant cyclic variability and instability in neighboring cylinders. The wavelet method and multiscale entropy analysis confirmed the results of the multifractal analysis, showing changes in the characteristics of the combustion process after the introduction of perturbations. The research-based on the first return map has shown an impact on the non-uniform and complex nature of the operation of the neighboring cylinders. The statistical analysis has shown that more than 60 % is slightly negatively skewness in most of the cases, and about 67 % of the cases indicate a leptokurtic distribution of IMEP. Finally, it is concluded that, the combustion of failure of one cylinder in a nine-cylinder engine affects the operation of the other cylinders, as demonstrated through advanced multifractal analysis techniques, return plots, return maps and multiscale entropy analysis.

Framework of Physically Consistent Homogenization and Multiscale Modeling of Beam Structures

In this work, a framework of physically consistent homogenization and multiscale modeling (PCHMM) is developed to analyze complex slender structures with homogenized one-dimensional beam models. Firstly, it is highlighted that periodic boundary conditions are not valid for the representative volume element (RVE)-based homogenizations if a shear-deformable beam model is to be obtained. Addressing this issue, physically consistent boundary conditions (PCBCs) are discussed in detail, which accounts for the influence of shear forces on the behavior of the slender structure and the corresponding RVE. A procedure of enforcing such boundary conditions is also given, applying sectional stresses to the RVE with fictitious DoFs. Additionally, we introduce a newly developed correct formula to calculate effective sectional properties which guarantee the cross-scale energy conservation though a modified Hill’s condition. The PCHMM framework, with homogenization/dehomogenization procedures using PCBC and the modified Hill’s condition, is also conveniently integrated into a commercial finite element software. The correctness and effectiveness of the developed framework of homogenization and multiscale analysis are demonstrated through several numerical examples, including lattice beams, twist-morphing metamaterial spars, and a realistic wing. The extension of this theory to plate/shell structures will be presented in our future work.

Multi-scale correlation analysis between geometric parameters and solar radiation in high density urban environment——Case study in Nanjing

This study explores the impact of multi-scale urban morphology on solar radiation in high-density environments, focusing on Nanjing as a case study. Using Grasshopper, the research decomposed urban models into four scales—district, block group, block, and plot—and analyzed eight morphological indicators, including site coverage (SC), floor area ratio (FAR), and block surface ratio (BSR). Solar radiation was simulated for the entire year, the summer solstice, and the winter solstice. Key findings reveal that different scales exhibit varying influences on solar radiation. At the district scale, BSR shows the highest correlation with annual solar radiation (R2 = 0.96), while at the neighborhood cluster scale, the minimum distance between buildings (DBmin) is most correlated (R2 = 0.7). At the block scale, BSR significantly correlates with summer solar radiation (R2 = 0.55). At the plot scale, no single indicator strongly correlates with solar radiation, but a combination of indicators is more relevant. These findings enable rapid solar performance assessments in urban design, promoting efficient solar energy use.

Multi-timescale feature extraction method of wastewater treatment process based on adaptive entropy

In wastewater treatment systems, extracting meaningful features from process data is essential for effective monitoring and control. However, the multi-time scale data generated by different sampling frequencies pose a challenge to accurately extract features. To solve this issue, a multi-timescale feature extraction method based on adaptive entropy is proposed. Firstly, the expert knowledge graph is constructed by analyzing the characteristics of wastewater components and water quality data, which can illustrate various water quality parameters and the network of relationships among them. Secondly, multiscale entropy analysis is used to investigate the inherent multi-timescale patterns of water quality data in depth, which enables us to minimize information loss while uniformly optimizing the timescale. Thirdly, we harness partial least squares (PLS) for feature extraction, resulting in an enhanced representation of sample data and the iterative enhancement of our expert knowledge graph. The experimental results show that the multi-timescale feature extraction algorithm can enhance the representation of water quality data and improve monitoring capabilities.

Understanding Ag liquid migration in SiC through ex-situ and in-situ Ag-Pd/SiC interaction studies

The effective containment of fission products (FPs) within tri-structural isotropic (TRISO) fuel particles is crucial for the safety and efficiency of High Temperature Gas-cooled Reactors (HTGRs). Combining multi-scale (µm to nm) and multi-dimensional (2D and 3D) analysis, this study focuses on the migration mechanisms of silver (Ag), for which the Ag-110 m FP isotope is radiotoxic, facilitated by reactions with palladium (Pd) alloys and the silicon carbide (SiC) layer at elevated temperatures (1300–1500 °C). Three primary pathways for Ag migration are identified: (1) diffusion in solid palladium silicide to form (Pd,Ag)2Si, (2) infiltration through cracks and pores in the carbon phase, and (3) liquid phase migration along SiC grain boundaries. Especially at temperatures above the melting point of Pd2Si (1404 °C), a ‘dissolution-recrystallisation’ mechanism is proposed of the Ag-Pd-Si liquid phase migrating along SiC grain boundaries. The study employs state-of-the-art in-situ heating transmission electron microscopy (TEM) techniques to directly observe the dynamic migration processes of Pd silicide within SiC, providing unprecedented insights into the liquid behaviour in TRISO fuel. These findings highlight the significant role of liquid phases in determining the transport of FPs through the TRISO-SiC which is vital for developing strategies that enhance the safety and efficacy of HTGRs.

VIBRATIONS OF A VERTICAL BEAM ROTATING WITH VARIABLE ANGULAR VELOCITY

An Euler-Bernoulli beam in vertical position rotating about its symmetry axis along its length is considered. The angular velocity is assumed to have small fluctuations about a constant mean velocity. The partial differential equation of motion is derived first. The equation is cast into a non-dimensional form. The natural frequencies are calculated for the pinned-pinned case. Principle parametric resonances such that the fluctuation frequency being close to two times one of the natural frequencies are considered. By employment of the Method of Multiple Scales, an approximate perturbation solution is found. The frequency response diagrams are drawn and the bifurcation points for transition from the trivial solution to the non-trivial solution are calculated. The conditions for which such resonances occur are exploited in the numerical results.

Multi scale analysis of social-ecological system of lobster (Panulirus spp.) fisheries in the Gunungkidul waters, Yogyakarta

Abstract Lobster is a high-value fisheries commodity in Gunungkidul Regency. Lobster resource management in the waters of Gunungkidul Regency has not been well identified in the social-ecological system (SES) framework. This study aims to describe and analyze the dynamics of interrelationships between the social-ecological system components of lobster fisheries in Gunungkidul Regency, which consists of the subsystem of resource systems (RS), resource units (RU), resource actors (RA), and resource governance (RG) and their interrelationships within and between subsystems to formulate a sustainable lobster management strategies in the waters of Gunungkidul Regency. This research was conducted from November 2022 until January 2023. The results of this study have indicated a dynamic interaction between the SES components of lobster fisheries. RS and RA are the SES components with the highest influence, so the slightest changes in RS and RA can cause co-evolutive changes to all the SES components of lobster fisheries in the waters of Gunungkidul Regency.

Multiscale Analysis of the Function Mechanism of Aging Action on the Adhesion Properties between Asphalt and Aggregate

Multiscale Analysis of the Function Mechanism of Aging Action on the Adhesion Properties between Asphalt and Aggregate

Framework of Physically Consistent Homogenization and Multiscale Modeling of Shell Structures**

A framework of physically consistent homogenization and multiscale modeling (PCHMM) for reduced-order analysis of plate/shell structures is developed in this paper. To address the inapplicability of conventional periodic boundary conditions and Hill’s condition involved in homogenization of shear-deformable shell structures, the paper proposes physically consistent boundary conditions and modified Hill’s condition for plate/shells. Unlike the PCHMM method for beams, considering the contradiction between high-order displacement fields induced by shear forces and low-order kinematic assumptions, additional constraints are applied to the plate/shell structure sectional strains during the solution of perturbation fields. The correctness and effectiveness of the proposed plate/shell PCHMM framework and method are verified by typical numerical examples. The proposed theory can also be conveniently embedded into commercial finite element software for homogenization and multiscale analysis of structures such as microscale metamaterials like lattice plates and large complex structures like aircraft fuselage sections.

Long-Term Monitoring and Analysis of Key Driving Factors in Environmental Quality: A Case Study of Fujian Province

Ecological environment quality reflects the overall condition and health of the environment. Analyzing the spatiotemporal dynamics and driving factors of ecological environment quality across large regions is crucial for environmental protection and policy-making. This study utilized the Google Earth Engine (GEE) platform to efficiently process large-scale remote sensing data and construct a multi-scale Remote Sensing Ecological Index (RSEI) based on Landsat and Sentinel data. This approach overcomes the limitations of traditional single-scale analyses, enabling a comprehensive assessment of ecological environment quality changes across provincial, municipal, and county levels in Fujian Province. Through the Mann–Kendall mutation test and Sen + Mann–Kendall trend analysis, the study identified significant change points in the RSEI for Fujian Province and revealed the temporal dynamics of ecological quality from 1987 to 2023. Additionally, Moran’s I statistic and Geodetector were employed to explore the spatial correlation and driving factors of ecological quality, with a particular focus on the complex interactions between natural factors. The results indicated that: (1) the integration of Landsat and Sentinel data significantly improved the accuracy of RSEI construction; (2) the RSEI showed a consistent upward trend across different scales, validating the effectiveness of the multi-scale analysis approach; (3) the ecological environment quality in Fujian Province experienced significant changes over the past 37 years, showing a trend of initial decline followed by recovery; (4) Moran’s I analysis demonstrated strong spatial clustering of ecological environment quality in Fujian Province, closely linked to human activities; and (5) the interaction between topography and natural factors had a significant impact on the spatial patterns of RSEI, especially in areas with complex terrain. This study not only provides new insights into the dynamic changes in ecological environment quality in Fujian Province over the past 37 years, but also offers a scientific basis for future environmental restoration and management strategies in coastal areas. By leveraging the efficient data processing capabilities of the GEE platform and constructing multi-scale RSEIs, this study significantly enhances the precision and depth of ecological quality assessment, providing robust technical support for long-term monitoring and policy-making in complex ecosystems.

Multi-scale analysis of harmonic resonance in cylindrical bubbles under acoustic excitation

In this paper, the dimensionless oscillation equation of a cylindrical bubble is analyzed using the multi-scale method, Lyapunov stability theory, and the Routh–Hurwitz stability criterion. The corresponding second-order analytical solution and stability criterion are obtained. By examining the cases of second-order super-harmonic resonance and 1/2-order sub-harmonic resonance, the harmonic resonance characteristics of cylindrical bubbles and the influencing factors are revealed. The conclusions are summarized as follows: (1) Super-harmonic resonance can exhibit up to three solutions, along with unstable phenomena such as jump and hysteresis. Sub-harmonic resonance, however, shows at most two solutions simultaneously, without jump or hysteresis phenomena. (2) As the acoustic excitation amplitude increases, both the response amplitude and the unstable zone significantly enlarge. An increase in nonlinear coefficients can reduce the response amplitude and increase instability. (3) When the acoustic excitation amplitude reaches a certain threshold, the oscillation mode of the bubble shifts from periodic to chaotic. Under the same initial conditions, the chaos threshold for sub-harmonic resonance is higher than that for super-harmonic resonance.

Multi-Scale analysis of the impacts of soil and water conservation practices and landscape on grain yield and return on investment in the sub-humid ethiopian highlands

Ethiopia's sub-humid highlands face a critical challenge in balancing agricultural productivity with land degradation. This study explores the effectiveness of soil and water conservation practices (SWCPs) in addressing this challenge. We investigated the interaction effects of types of SWCPs, landscape positions, and location on Teff (Eragrostis teff) and wheat (Triticum aestivum) yield. In addition, we assessed the economic viability of SWCPs using cost-benefit analysis with farmer-funded and cost-sharing scenarios. The results indicated that yield was significantly affected by the interactions between factors like SWCP type and landscape position. Soil bunds consistently increased crop yield across diverse locations and landscapes, indicating superior erosion control benefits. Lower landscape positions on foot slopes benefited most from SWCP implementation. Teff yield increased by 188 % and wheat yield by 181 % under soil bunds. The cost-benefit analysis confirmed the financial viability of SWCPs, particularly for Teff (NPV = 4499.35 USD, IRR = 50 %, and BCR = 1.51) and wheat (NPV = 544.35 USD, IRR = 16 %, and BCR = 1.06) grown on lower landscapes with farmer-funded investment scenarios. Positive return on investment was observed in both scenarios, with cost-sharing offering greater economic benefits for farmers. These findings highlight the importance of an integrated approach to SWC implementation for achieving multiple Sustainable Development Goals (SDGs) by enhancing food security, improving farmer incomes, and promoting sustainable and productive landscape management practices. Future research should explore the long-term sustainability of SWCPs, their adaptation across diverse agroecological zones and landscapes, the incorporation of various crops, the broader socioeconomic impacts, and the development of effective extension programs for wider adoption by farmers.

Analyzing the Stability of a Connected Moving Cart on an Inclined Surface with a Damped Nonlinear Spring

This paper examines the stability behavior of the nonlinear dynamical motion of a vibrating cart with two degrees of freedom (DOFs). Lagrange’s equations are employed to establish the mechanical regulating system of the examined motion. The proposed approximate solutions (ASs) of this system are estimated through the use of the multiple-scales method (MSM). These solutions are considered novel as the MSM is being applied to a new dynamical model. Secular terms have been eliminated to meet the solvability criteria, and every instance of resonance that arises is categorized, where two of them are examined concurrently. Therefore, the modulation equations are developed based on the representations of the unknown complex function in polar form. The solutions for the steady state are calculated using the corresponding fixed points. The achieved solutions are displayed graphically to illustrate the impact of manipulating the system’s parameters and are compared to the numerical solutions (NSs) of the system’s original equations. This comparison shows a great deal of consistency with the numerical solution, which indicates the accuracy of the applied method. The nonlinear stability criteria of Routh–Hurwitz are employed to assess the stability and instability zones. The value of the proposed model is exhibited by its wide range of applications involving ship motion, swaying architecture, transportation infrastructure, and rotor dynamics.

Investigation on mechanical properties and stealth characteristics of a novel gradient-stitched composite structure

Based on the far field function of electric field, a new glass carbon fiber gradient-stitched structure is proposed and designed in the paper. In the frequency range of 8–28 GHz, the electric field distribution of transverse electric and magnetic field (TEM) waves incident obliquely on the surface of the structure by optimizing the glass fiber fabric units. It is confirmed that the surface has the function of suppressing electromagnetic wave reflection. The electrical performance simulation and testing results of the structure show that the radar cross section (RCS) is reduced by 90% in the frequency range of 12.3–26.5 GHz. In addition, a multi-scale analysis model is established to quickly predict the tensile modulus and strength of the composite material. The strength and modulus reached 26.9 GPa and 403 MPa, respectively. The simulating and testing results of mechanical properties are in good agreement.

Basin-scale exhumed Cretaceous fluvial systems (Chubut Group, Cañadón Asfalto basin), central Patagonia, Argentina

This contribution describes basin-scale, Cretaceous (Late Aptian to Cenomanian-Early Turonian) fluvial systems outcropped over ∼30,000 km2 that contain more than 7000 exhumed paleochannels in the Chubut Group, Cañadón Asfalto basin (central Patagonia), Argentina. Paleochannels are encased within a ∼350 m thick stratigraphic interval (∼20 My) including volcaniclastic and epiclastic fluvial units (Cerro Barcino and Puesto Manuel Arce formations). Geomorphologically, the exhumed paleochannels conform to isolated sandstones/conglomeratic ridges, a swarm of paleochannels, and elongated/equidimensional mesas (plateaus), characterizing much of the “mesetiform” landscape in central Chubut. The plan-view analysis of exhumed paleochannels mainly shows a mean WNW-ESE orientation (112°–292°) and predominance of narrow (83.1%) and very narrow (14.4%), low-sinuosity channels (96%). A plan-view multi-scale architectural analysis of sandbodies allows us to recognize different fluvial hierarchies: a) 3rd-order lithosomes (macroform growth increments), b) 4th-order lithosomes (point bars and crevasse-channels), b) 5th-order lithosomes (main channels), and c) 6th-order lithosomes (channel belts). Two main types of channel arrangements in the exhumed fluvial systems were recognized: fixed-channel and mobile channel belts. We observed a broad relationship between geomorphologic configurations and fluvial architectural units. Some macro spatiotemporal variation in the fluvial architecture was observed towards the youngest positions, including wider channels and a greater relative abundance of high-sinuosity channels with point bars. The basin-scale distribution of exhumed paleochannels would allow us to infer the predominance of shallow lacustrine or lagoon deposits in the western basin region, probably controlled by the inherited topography of the Jurassic- Early Cretaceous depocenters.