Nonlocal Material Research Articles

Influence of the homotopy stability perturbation on physical variations of non-local opto-electronic semiconductor materials

In the current work, we investigate a novel technique specialized in stability perturbation theory to analyze the primary variations such as thermal, carrier, elastic, and mechanical waves in photothermal theory. The interface of the non-local semiconductor material is utilized to study the stability analysis. The problem is established using a 1D opto-electronic-thermoelastic deformation in the context of the photo-thermoelasticity (PTE) framework. The Laplace transform method is used to convert the system from the time domain into the frequency domain, and the boundary conditions for the thermal, elastic, and plasma waves are applied to the interface of the medium. The homotopy perturbation method was used as an innovative approach to analyze the stability of the non-local silicon’s primary physical fields. The numerical inversion method is applied, yielding many graphs focusing on important numerical factors such as non-local effects, thermo-energy, and thermo-electric coupling parameters. Investigating dual solutions between stable and unstable regions for critical parameters like thermo-electric and thermo-energy coupling factors demonstrates that the homotopy perturbation technique can effectively analyze the stability analysis. The comparison between silicon and germanium is illustrated graphically. Utilizing the homotopy perturbation technique, we can effectively examine the stability of the primary physical variations with the effect of some values for eigenvalues approaches.Graphical abstract

Reflection phenomena of thermoelastic plane waves on a rigid surface within a size-dependent elastic media

The current investigation aims to comprehend the spread of time-harmonic thermoelastic plane waves in an isotropic and homogeneous nonlocal elastic material without bounds, within the framework of the Lord–Shulman model and Eringen’s nonlocal stress model. Our analysis reveals two sets of coupled longitudinal waves and one independent shear-type wave. The coupled longitudinal waves experience dispersion and damping over time due to the dissipative nature of the L-S model. In contrast, the vertically shear-type waves exhibit dispersion characteristics due to the presence of nonlocality in the medium. Furthermore, we observe that the shear-type wave encounters a critical frequency, while the coupled longitudinal waves may face critical frequency conditions under certain circumstances. We explore the reflection of thermoelastic waves at a rigid, thermally insulated, and isothermal boundary of a thermoelastic half-space, particularly in the case of an incident coupled longitudinal thermoelastic wave. We determine the amplitude ratios of the reflected waves to the incident wave through analytical methods. For a specific model, we generate various graphs to analyze the behavior of phase speeds, attenuation coefficients, and reflection coefficients. To assess the impact of the elastic nonlocal parameter on the variations of phase speeds, attenuation coefficients, and amplitude ratios of the reflected waves, we present graphical representations. Notably, our observations indicate that all waves are influenced by the nonlocality of the medium. Longitudinal waves exhibit sensitivity to thermal parameters, whereas the shear-type wave remains independent of thermal effects. Furthermore, the presence of elastic nonlocality results in a reduction in the classical shear-type wave speed.

Tracing the origin of raw materials used for the production of ancient ceramics: a case study of multi-period archaeological sites in the Turopolje area (Continental Croatia)

The selection of raw materials for ancient pottery production was influenced by a variety of technological and cultural factors, underscoring the importance of characterising these materials to understand the technology of ancient societies. This research examines ancient ceramics from two multi-period archaeological sites: Staro Čiče-Gradišće (Neolithic, Copper Age, Copper/Early Bronze Age, Early Bronze Age, Late Bronze Age, Roman period, and Late Mediaeval period) and Kurilovec-Belinščica (Early Bronze Age and Middle/Late Bronze Age), alongside potential clayey raw materials collected near these settlements. Using a multi-analytical approach (optical microscopy, X-ray powder diffraction, mass and emission spectrometry, and laser granulometry), the research aims to determine the characteristics of the paste recipes (raw clay and tempers) and to examine the type and provenience of the raw materials used for ancient pottery production over different periods of the past (from the Neolithic to the Late Mediaeval period). The results showed that ancient potters preferred to use moderately plastic, sandy clay, while Bronze Age potters often used highly plastic clay. Potters utilised various non-plastic tempering materials, such as sands and gravels, grog, and mollusc shells, with their choice being influenced by the need to enhance technological properties as well as by regional and culturally determined pottery traditions. Most of the ceramics are of local origin, made from easily available raw materials that represent flood sediments of the nearby Sava River. However, non-local materials were detected in Neolithic samples, indicating the presence of exchange networks among those communities.

A finite element based approach for nonlocal stress analysis for multi-phase materials and composites

AbstractThis study proposes a numerical method for calculating the stress fields in nano-scale multi-phase/composite materials, where the classical continuum theory is inadequate due to the small-scale effects, including intermolecular spaces. The method focuses on weakly nonlocal and inhomogeneous materials and involves post-processing the local stresses obtained using a conventional finite element approach, applying the classical continuum theory to calculate the nonlocal stresses. The capabilities of this method are demonstrated through some numerical examples, namely, a two-dimensional case with a circular inclusion and some commonly used scenarios to model nanocomposites. Representative volume elements of various nanocomposites, including epoxy-based materials reinforced with fumed silica, silica (Nanopox F700), and rubber (Albipox 1000) are subjected to uniaxial tensile deformation combined with periodic boundary conditions. The local and nonlocal stress fields are computed through numerical simulations and after post-processing are compared with each other. The results acquired through the nonlocal theory exhibit a softening effect, resulting in reduced stress concentration and less of a discontinuous behaviour. This research contributes to the literature by proposing an efficient and standardised numerical method for analysing the small-scale stress distribution in small-scale multi-phase materials, providing a method for more accurate design in the nano-scale regime. This proposed method is also easy to implement in standard finite element software that employs classical continuum theory.

Re-thinking the concept of embedded procurement: Insights from the lower Paleolithic of the Levant

Binford’s concept of embedded procurement, proposed over half a century ago, which suggests that lithic procurement was typically integrated with other subsistence activities, has become a cornerstone of raw material studies, and continues to dominate interpretations by many archeologists studying Lower and Middle Paleolithic flint sourcing. However, evidence from Lower Paleolithic Acheulo-Yabrudian Qesem Cave, and the Lower and Middle Paleolithic Dishon and Achbara flint extraction and reduction complexes, in Israel, suggests that this view warrants reconsideration. At Qesem Cave, significant proportions of non-local materials, particularly within specific typo-technological categories, indicate a selective approach to the procurement and exploitation of different flint types, including evidence of long-distant procurement. At Dishon and Achbara, multiple flint extraction and reduction tailing piles have been identified, featuring rejected handaxes and Levallois cores, and the geochemical composition similarity between this flint and handaxes from the Acheulian sites of at Ma’ayan Barukh and Gesher Benot Ya’aqov (GBY), both located ∼ 20 km from the Dishon complex, suggesting the existence of task-specific forays, dedicated to the organized extraction of flint. Based on these finds, we propose that the predominance of the embedded procurement model should be reassessed, as direct procurement strategies were already in use during the Lower Paleolithic of the Levant. Moreover, drawing on archaeological and ethnographic data, we argue that cultural, social, cosmological, and ontological factors also influenced lithic materials procurement practices among Lower Paleolithic populations.

Middle Stone Age technological organisation from MIS 5 at Mertenhof Rockshelter, South Africa

Lithic technological organisation within the southern Africa Early Middle Stone Age (∼315,000–80,000 years ago) has seen relatively little investigation owing to the subtly of technological change, frequent use of locally derived raw materials, and the archaeological spatio-temporal discontinuity. This has resulted in relatively limited use of explanatory models for technological variability, including mobility, provisioning, tool production, and core reduction strategies. This paper uses 2952 artefacts to test the lithic technological organisation across Marine Isotope Stage 5 units of Mertenhof Rockshelter. Here we argue that the scales and concepts currently used to approach Early Middle Stone Age technology requires reconsideration. The Mertenhof sequence exhibits high proportions of non-local raw materials with their transport reflective of tactical adjustments within relatively stable mobility, provisioning, and reduction strategies. We demonstrate that Early Middle Stone Age populations maintained a diverse array of tactical solutions across these strategic domains, offering a durable and flexible strategy that would be adapted to changing contexts.

Nonlocal dynamic response of FGP sandwich microbeam with 2D PSH network incorporating adatoms-surface interactions energy under magnetic field

The present work models and studies the resonance frequency change due to adsorption phenomena in a simply-supported adatom-microbeam system under an axial magnetic environment. The microbeam structure is a functionally graded (FG) sandwich that includes a rectangular configuration and a ceramic perforated core with periodic square holes network and FG porous material faces. To evaluate the adsorption-induced energies produced by van der Waals interaction (vdW), the Morse and Lennard-Jones (6–12) potentials are included in conjunction with nonlocal material elasticity to adopt the small-scale impact. Moreover, the explicit formulas for the inertia moments and shear force are developed by the Timoshenko beam equations, considering the residual stress influence as an additional axial load. The Navier-type solution and the differential quadratic method (DQM) are implemented to compute the solution of the governing equations. It is established that the resonance frequency change for the O/Si (100) and H/Si (100) is dependent on the geometrical, perforation, and porosity parameters, adsorption density, mode number, and the magnetic field intensity as well. Therefore, these numerical results have been discussed in detail to properly examine dynamic vibration behavior and a suitable mass detection design of M/NEMS structures.

Petrology and Provenance Study of Stone Artifacts from the Mesolithic Cave of Kouvaras in Attica: A Preliminary Report

ABSTRACT This paper focuses on the lithology and raw material provenance of stone artifacts discovered in the prehistoric cave of Kouvaras in Eastern Attica, dating back to the 10th-9th millennia B.C. The study aims to determine whether these prehistoric artifacts were made on local or non-local raw materials. The research consists of two main components: a field study to detect the geological features of the region and collect raw material samples, and a laboratory investigation using XRD, SEM and p-XRF techniques to conduct a petrological analysis. The results suggest that relying solely on chert chemistry to effectively determine the sources of chert artifacts is not a reliable method. By combining several analytical methods and taking a holistic approach, researchers can gain valuable insights into prehistoric human interactions with the local geological environment and the use of available natural resources to make artifacts in prehistoric times.

Does engagement matter? The impact of patient and community engagement on implementation of cardiovascular health materials in primary care settings

BackgroundEngaging patients and community members in healthcare implementation, research and evaluation has become more popular over the past two decades. Despite the growing interest in patient engagement, there is scant evidence of its impact and importance. Boot Camp Translation (BCT) is one evidence-based method of engaging communities in research. The purpose of this report is to describe the uptake by primary care practices of cardiovascular disease prevention materials produced through four different local community engagement efforts using BCT.MethodsEvidenceNOW Southwest (ENSW) was a randomized trial to increase cardiovascular disease (CVD) prevention in primary care practices. Because of its study design, Four BCTs were conducted, and the materials created were made available to participating practices in the “enhanced” study arm. As a result, ENSW offered one of the first opportunities to explore the impact of the BCT method by describing the uptake by primary care practices of health messages and materials created locally using the BCT process. Analysis compared uptake of locally translated BCT products vs. all other products among practices based on geography, type of practice, and local BCT.ResultsWithin the enhanced arm of the study that included BCT, 69 urban and 13 rural practices participated with 9 being federally qualified community health centers, 14 hospital owned and 59 clinician owned. Sixty-three practices had 5 or fewer clinicians. Two hundred and ten separate orders for materials were placed by 43 of the 82 practices. While practices ordered a wide variety of BCT products, they were more likely to order materials developed by their local BCT.ConclusionsIn this study, patients and community members generated common and unique messages and materials for cardiovascular disease prevention relevant to their regional and community culture. Primary care practices preferred the materials created in their region. The greater uptake of locally created materials over non-local materials supports the use of patient engagement methods such as BCT to increase the implementation and delivery of guideline-based care. Yes, patient and community engagement matters.Trial registration and IRBTrial registration was prospectively registered on July 31, 2015 at ClinicalTrials.gov (NCT02515578, protocol identifier 15–0403). The project was approved by the Colorado Multiple Institutional Review Board and the University of New Mexico Human Research Protections Office.

NotaryVault: Secure Document Authentication on Blockchain

The Notarial Office(NO), working on providing various essential certificates, still relies on manual handling and requires paper materials from other government departments. That brings lots of inconvenience. The Notarial Office rejects non-local paper materials for their lower credibility in the local place and then cannot provide cross-border services. It also easily causes sensitive information leakage as copies of paper materials have been stored. In this case, a blockchain-based system is suitable to address challenges in this scenario because of its advantages (e.g, decentralized, immutability, transparency, auditability). We implemented this system on top of the Hyperledger Fabric. Moreover, we replace manual operations with smart contracts, set extra ledgers to off-load different types of transactions and provide encryption for private information when needed. In the end, we get the expected result. That is, the modification outperformed the unmodified network in experiments.

Social Organization, Intersections, and Interactions in Bronze Age Sardinia. Reading Settlement Patterns in the Area of Sarrala with the Contribution of Applied Sciences

Abstract Bronze Age sites in the coastal area of Sarrala, in Eastern Sardinia, have been subjected to survey and excavation over the last half-century. The study area, whose social and economic evolution and changing scales of interactions are traced through settlement patterns and building analysis, is interpreted in light of more general trends suggested by stable isotopes, archaeogenetics, and paleoclimatology. The local picture of progressive demographic growth and infilling of the landscape, with a subsequent concentration of population and labor, follows a sequence widely detected in Sardinia. More specific identifiable aspects include a comparatively higher fragmentation/competition (ratio of complex vs simple nuraghes; ratio of tombs vs nuraghes) and a consistent pattern in the distribution of non-local building materials in the latest phase at the sites showing archaic features, taken as a clue of a long-lasting authority at select sites. These elements are compatible with organized pastoral exploitation of the available territory, structured according to patrilocality and closeness to ancestral lineages and residences. The interplay of internal dynamics relative to constraints and opportunities is discussed, such as climate change and long-distance trade connections, with possible implications for interpreting Nuragic society.

Optoelectronic–thermomagnetic effect of a microelongated non-local rotating semiconductor heated by pulsed laser with varying thermal conductivity

Abstract In this study, we investigated the effect of a rotation field and magnetic field on a homogeneous photo-thermoelastic nonlocal material and how its thermal conductivity changes as a result of a linearly distributed thermal load. The thermal conductivity of an interior particle is supposed to increase linearly with temperature under the impact of laser pulses. Microelastic (microelements distribution), non-local semiconductors are used to model the problem under optoelectronic procedures, as proposed by the thermoelasticity theory. According to the microelement transport processes, the micropolar-photo-thermoelasticity theory accounts for the medium’s microelongation properties. This mathematical model is solved in two dimensions using the harmonic wave analysis. Non-local semiconductor surfaces can generate completely dimensionless displacement, temperature, microelongation, carrier density, and stress components with the appropriate boundary conditions. The effects of thermal conductivity, thermal relaxation times, magnetic pressure effect, laser pulses, and rotation parameters on wave propagation in silicon (Si) material are investigated and graphically displayed for a range of values.

Periodic transmission theory of circularly symmetric multi-ring solitons in nonlinear Schrödinger equation

In this paper, the evolution characteristics of periodic transmission of circularly symmetric multi-ring solitons in optical nonlocal materials based on nonlinear Schrödinger equation are investigated in detail. The transmission expression of circularly symmetric multi-ring solitons has been derived. It was found that the number and size of rings in these solitons can be controlled by initial parameters. The transmission of circularly symmetric multi-ring solitons is similar to that of high-order temporal solitons in nonlinear fibers, exhibiting periodic variations. When the input energy is a specific value, the statistical width of circularly symmetric multi-ring solitons remains constant during transmission, otherwise it exhibits periodic changes, which can be considered as generalized breathing solitons. The influence of various parameters on the transmission characteristics has been analyzed in detail, and some important transmission characteristics have been intuitively demonstrated through numerical simulation.

Nonlocal interfaces accounting for progressive damage within continuum-kinematics-inspired peridynamics

In this work, we present a modeling approach to nonlocal material interfaces in the framework of continuum-kinematics-inspired peridynamics. The nonlocal model accounts for progressive damage within a finite-thickness interface, as opposed to the more common practice of abrupt bond breakage across a zero-thickness interface. Our approach is based on an overlap of the constituents within the interface. Interfacial bonds between initially overlapping partner points are governed by a constitutive law reminiscent of a traction-separation-law. The governing equations for continuum-kinematics-inspired peridynamics in the presence of an interface are derived using a rate-variational principle. The damage formulation is established using the classical concept of internal variables. Following the notion of a standard dissipative material, thermodynamic consistency of the constitutive laws and the evolution of the internal variables is ensured. The latter results in a straightforward evaluation of a damage function. We give details about the computational implementation comprising a peridynamic discretization and a Newton–Raphson scheme. A sound approach to approximate the interface normal during deformation is presented, which allows to penalize material penetration across the interface. The proposed model is explored in a series of numerical examples, i.e., classical peeling and shearing tests, for a variety of damage functions. A key feature of our interface model are the nonlocal characteristics that are assumed to play a role especially at small scales. We, first, observe that an increasing thickness of the nonlocal interface leads to stronger interfacial bonding and less damage. Second, an increase in horizon size results in stiffer material behavior. When studying the wrinkling and delamination behavior of a compressed bilayer, it is found that an increase in interface stiffness leads to a smaller wrinkling wavelength. Moreover, delamination due to progressive damage of interfacial bonds in the post-wrinkling regime is observed, which, to the best of our knowledge, has not been studied in a nonlocal model before.

Nonlinear Vibration of Function Graded Magneto-electro-elastic Microplates using Nonlocal Stress Theory

This work presents an analysis of nonlinear vibration in Function Graded Magneto-Electro-Elastic (FG-MEE) plates subjected to mechanical, electrical, and magnetic loads using the nonlocal stress theory approach. In this study two types of MEE plates, namely BaTiO3 and CoFe2O4 were considered. The basic equations are derived using classical plate theory with nonlocal stress theory and are solved using the Galerkin method and Runge-Kutta method. We investigated the effects of nonlocal parameters, materials, and geometrical characteristics on the natural frequencies and nonlinear vibration of the FG-MEE microplates.
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On the physical significance of non-local material parameters in optical metamaterials

When light interacts with a material made from subwavelength periodically arranged constituents, non-local effects can emerge. They occur because of either a complicated response of the constituents or possible lattice interactions. In lowest-order approximations of a general non-local response function, phenomena like an artificial magnetism and a bi-anisotropic response emerge. However, investigations beyond these lowest-order descriptions of non-local effects are needed for optical metamaterials (MMs) where a significant long-range interaction becomes evident. This highlights the need for additional material parameters to account for spatial non-locality in an effective medium description. These material parameters emerge from a Taylor expansion of the general and exact non-local response function. Even though these non-local parameters improve the effective description, their physical significance is yet to be understood. To improve the situation, we consider a conceptional MM consisting of scatterers characterized by a prescribed multipolar response arranged on a square lattice. Lorentzian polarizabilities describe the scatterers in the electric dipolar, electric quadrupolar, and magnetic dipolar terms. A slab of such a MM is homogenized while considering an increasing number of non-local terms in the constitutive relations at the effective level. We show that the effective permittivity and permeability are linked to the electric and magnetic dipole moments of the scatterers. The non-local material parameters are related to the higher-order multipolar moments and their interaction with the dipolar terms. Studying the effective material parameters with the knowledge of the induced multipolar moments in the lattice facilitates our understanding of the significance of each material parameter. Our insights aid in deciding on the order to truncate the Taylor expansion of the considered constitutive relations for a given MM.

A changeable thermal conductivity and optoelectronic-mechanical wave behavior in a microelongated, non-locally rotating semiconductor media

In this study, we investigate the effect of a rotation field on a homogeneous photo-thermoelastic nonlocal material and how its thermal conductivity changes as a result of a linearly distributed thermal load. The thermal conductivity of an interior particle is supposed to increase linearly with temperature. Microelastic, non-local semiconductors are used to model the problem in accordance with optoelectronic procedures, as proposed by the thermoelasticity theory. The micropolar-photo-thermoelasticity theory takes into account the medium’s microelongation properties in accordance with the microelement transport processes. This mathematical model is solved in two dimensions (2D) using harmonic wave analysis. Dimensionless components of displacement, temperature, microelongation, carrier density, and stresses are generated when the non-local semiconductor surface is subjected to the right boundary conditions. For silicon (Si) material, the wave propagation impact of the main physical fields is examined and graphically shown for various values of variable thermal conductivity, thermal relaxation durations, nonlocality, and rotation parameters.

Nonlinear Vibration and Stability Analysis of Rotating Functionally Graded Piezoelectric Nanobeams

Presented herein is an investigation for the nonlinear vibration and stability analysis of rotating functionally graded (FG) piezoelectric nanobeams based on the nonlocal strain gradient theory. The present model can be regarded as a simplified version for the rotating nanowire of biomechanical nanogenerators. The Hamilton principle is used to derive nonlinear equations of motion and their related boundary conditions, which are then discretized to form a set of algebraic equations. Accordingly, the nonlinear vibration frequencies and buckling loads of the nanobeams can be determined by an iterative method. A parametric study of rotational velocity, nonlocal parameter, material length parameter, power-law index, and electrostatic voltage on the dynamic stability behavior of such nanobeams is also presented. In the cantilever case, increasing the nonlocal parameter and material length parameter can result in a stiffness-hardening effect that is unaffected by rotational velocity and the material length parameter to nonlocal parameter ratio. Yet, this has not been reported previously. More importantly, incorporating the effect of geometric nonlinearity on the dynamic responses and stability results of the nanobeams is indispensable. In particular, new observations for the coupling effect of vibration amplitude and power-law index on the electric potential effect are useful for the design of rotating microelectromechanical devices.

Nonlocal fiber-reinforced double porous material structure under fractional-order heat and mass transfer

PurposeThe purpose of this study is to analyze the thermo-diffusion process in a semi-infinite nonlocal fiber-reinforced double porous thermoelastic diffusive material with voids (FRDPTDMWV) in light of the fractional-order Lord–Shulman thermo-elasto-diffusion (LSTED) model. By virtue of Eringen’s nonlocal elasticity theory, the governing equations for the considered material are developed. The free surface of the substrate is governed by the inclined mechanical load and thermal and chemical shocks.Design/methodology/approachWith the aid of the normal mode technique, the solutions of the nondimensional coupled governing equations have been obtained.FindingsThe expressions of field variables are obtained analytically. By using MATHEMATICA software, various graphical implementations are presented to describe the impacts of angle of inclination, fractional-order and nonlocality parameters. The present model is also validated on the basis of some comparative studies with some preestablished cases.Originality/valueAs observed from the literature survey, many different studies have been carried out by taking into account the deformation analysis in nonlocal double porous thermoelastic material structures and thermo-mechanical interaction in fiber-reinforced medium under fractional-order thermoelasticity theories. However, to the best of the authors’ knowledge, no research emphasizing the thermo-elasto-diffusive interactions in a nonlocal FRDPTDMWV has been carried out. Moreover, the effect of fractional-order LSTED theory on fiber-reinforced thermoelastic diffusive half-space with double porosity has not been illuminated till now, which significantly defines the novelty of the conducted research.

Effects of changing thermal conductivity on photothermal excitation in non-local semiconductor material subjected to moisture diffusion and laser pulses

A novel model is presented in this study for the situation of wave interference in a non-local stimulated semiconductor medium, including thermal, plasma, and elastic waves. Moisture diffusion in one dimension (1D) has been included in the governing equations by varying the non-local medium's thermal conductivity under the impact of laser pulse according to the non-Gaussian temporal profile. The dimensionless model was characterized by linear transformations. Analytical solutions were obtained by applying Laplace transforms to a description of the governing equations based on the photo-thermoelasticity theory based on moisture diffusivity and variable thermal conductivity. When applying certain of the circumstances (thermal ramp type and non-Gaussian plasma shock), linear solutions are achieved in the time domain using various numerical techniques based on inverse Laplace transforms. Some of the physical variables being studied are visually shown via numerical simulation. The present investigation has produced numerous important concrete instances. Using graphs and theoretical descriptions, several contrasts are drawn, while certain physical factors, such as relaxation durations, changing thermal conductivity, non-local parameters, and reference moisture values, are in play.