Behavior Of Characteristics Research Articles

Analysis of electroosmotic flow in a symmetric wavy channel containing anisotropic porous material with varying zeta potential

The present study examines an asymptotic analysis of electroosmotic flow phenomena bounded by the symmetrical wavy channel containing an anisotropic porous material under the variable pressure gradient and zeta potential. The incorporation of anisotropic porous material introduces additional complexities to the flow behavior. Electric potential is regulated by the non-linear Poisson–Boltzmann equation, which is linearized by the Debye–Hückel linearization process, and flow velocity inside the porous channel is governed by the Brinkman equation. The aspect ratio of the channel is considered to be significantly small, i.e., (δ2≪1). Obtaining analytical solutions to these non-linear coupled equations is a formidable challenge. To address this challenge, the equations are tackled by employing an asymptotic series expansion with respect to a small parameter, specifically the ratio of the channel thickness, where δ2≪1. The graphical analysis based on the derived expressions for flow quantities—such as fluid velocity, flow rate, flow resistance, wall shear stress, and pressure gradient along the wall—demonstrates the considerable impact of various governing parameters. These parameters, including the Debye–Hückel parameter, anisotropic ratio, slip length, and fluctuation amplitude, play a crucial role in influencing the behavior of these flow characteristics, highlighting their importance in determining the system's overall flow dynamics. The results demonstrate that an increment in the anisotropic ratio corresponds to an enhancement in fluid velocity and augmented flow rate. This relationship stems from the observed phenomenon wherein an enhancement in the anisotropic ratio leads to an augmentation in the permeability along the x-direction, thereby leading to an elevation in velocity and subsequently enhancing the flow rate. The study also examines the impact of flow reversal at the crests of the wavy channel resulting from the anisotropic ratio. The findings from our study have confirmed the axial fluid velocity in a purely pressure-driven flow system, where electroosmotic effects are not present. These results enhance our understanding of how anisotropic permeability affects fluid flow in microfluidic systems, especially when electrokinetic forces are at play.

Estimation of long-term stability of precision inductance measures using different methods

Abstract Inductance is a physical quantity that characterizes the ability of a conductor to accumulate magnetic field energy when electric current flows. Considering the small number of standards of a similar level of accuracy in the world, it is interesting to study the behavior of individual characteristics of such standards using known research methods. The long-term stability of measures is an important metrological characteristic that characterizes the change in the nominal value of a standard or measure over time. Regular metrological research of the long-term stability of precision inductance measures with nominal values of 10 mH and 100 mH have been carried out since 2009. Analysis of the long-term behavior of precision inductance measures included checking the primary measurement data for randomness and outliers using Abbe’s and Grubb’s tests. The detection of anomalous results significantly affects the estimation of the random error component and the standard uncertainty of the reproduction of the inductance measure. There is a significant change in the inductance of both measures over the entire observation period, which is confirmed by Abbe’s test. At the same time, this change is most significant in the first years, and then the change in inductance occurs slowly. The analysis of the functional change in inductance using the Grabb’s test showed that, depending on the research object itself, different analytical dependencies can be used for describing the functional trend. The criterion for choosing the best approximation can be both the “criterion of the reliability of the approximation” and the standard deviation of the “cleaned” measured data. The practical value of this work is the possibility of accumulating and integrating the obtained experimental data for standards of a similar accuracy class in different countries, which makes it possible to further improve the methods of their construction, stabilization of reproducible characteristics and operational features.

Changes in visitor behaviour across COVID-19 pandemic: Unveiling urban visitation dynamics and non-linear relationships with the built environment using mobile big data

COVID-19 has significantly affected the behavioural patterns of urban visitors. However, the non-linear relationships between visitor behaviour and built environments, particularly how these relationships have evolved during the pandemic, have not yet been extensively studied. Using over 10 million mobile big data records collected over three years in Fukuoka, Japan, incorporating the XGBoost machine learning model and SHAP-PDP interpretation method, we identified non-linear relationships between visitor behaviours and built environments. Our findings uncovered significant non-linear impacts on visitor behaviour of several urban characteristics, such as floor area ratio, building coverage ratio, road density, and POI richness. Notably, the floor area ratio exhibits a negative correlation with visit frequency below 1 but a positive correlation above 2. Building coverage ratio positively impacts visit frequency up to 1000 m2 per 10,000 m2, after which it turns negative; this correlation shifted towards a consistent negative trend during the pandemic. Road density, which usually correlates negatively with visit duration, became positively correlated above 700 m2 per 10,000 m2 during the pandemic. Similarly, the influence of floor area ratio on visit duration reversed from negative to positive under pandemic conditions. Revealing the dynamic and non-monotonic nature of how urban visitors respond to the built environment under the influence of the pandemic, our results provide valuable insights for urban planning strategies in response to crisis resiliently.

Solution of the problem with a small parameter in suspension filtration in a porous medium

Relevance. The necessity to calculate the changes in filtration properties during injection of suspensions for subsequent forecasting of technological parameters of wells. This calculation is complicated by the presence of different-scale effects, since the penetration depth of dispersed particles is orders of magnitude smaller than the characteristic dimensions of the formation. These effects have not been studied in detail before. Aim. To analyze the effect of a small parameter on the behavior of flow characteristics using a mathematical model of suspension filtration in a porous medium. Objects. Colmatation coefficient, filtration coefficient, distribution of concentration of dispersed particles in the formation, porosity, mathematical model of deep-bed suspension migration into a porous medium. Methods. Numerical modeling, explicit finite-difference scheme, solution of a problem with a small parameter, introduction of dimensionless parameters, method of characteristics. Results and conclusions. It is shown that the processes of conformance control and colmatation of a porous medium are described within the framework of a unified system of equations of deep-bed suspension migration into a porous medium. It is identified that the concentration of retained particles is a small parameter that allows reducing the complete system of equations of deep-bed suspension migration into a porous medium to a simplified form, in which the solution can be obtained analytically using the method of characteristics. The authors compared the solutions of the complete and simplified systems of equations of deep-bed suspension migration into a porous medium, indicating their compliance with an error of less than 4 %. They obtained the distributions of the concentration of dispersed particles and porosity in the reservoir during colmatation, showing that over time the colmatation front propagates at a constant rate. It is shown that the colmatation coefficient is a small parameter that significantly determines the nature of oil displacement by water, and a decrease in the colmatation coefficient leads to a decrease in the rate of colmatation and the appearance and growth of the size of the stabilized zone near the displacement front.

Hysteresis and self-oscillations in an artificial memristive quantum neuron

We theoretically study an artificial neuron circuit containing a quantum memristor in the presence of relaxation and dephasing. The charge transport in the quantum element is realized via tunneling of a charge through a quantum particle which shuttles between two terminals—a functionality reminiscent of classical diffusive memristors. We demonstrate that this physical principle enables hysteretic behavior in the current-voltage characteristics of the quantum device. In addition, being used in an artificial neural circuit, the quantum switcher is able to generate self-sustained current oscillations. Our analysis reveals that these self-oscillations are triggered only in quantum regimes with a moderate rate of relaxation, and cannot exist either in a purely coherent regime or at a very high decoherence. We investigate the hysteresis and instability leading to the onset of current self-oscillations and analyze their properties depending on the circuit parameters. Our results provide a generic approach to the use of quantum regimes for controlling hysteresis and generating self-oscillations. Published by the American Physical Society 2024

Effect of symmetrical biaxial tension on the magnetic properties of the composite specimen of two steel plates with different mechanical and magnetic properties

The results of studying the behavior of the magnetic characteristics of two-layer material containing layers of annealed sheet low-carbon Steel 15 and sheet metastable austenitic 12Kh18N9Т steel, subjected to cold rolling with a compression of 50 %, under biaxial symmetric tension have been presented. Experiments on biaxial deformation were carried out on the original biaxial testing machine, allowed to determine the physical properties of materials during elastic-plastic deformation independently along two axes. It has been shown that the coercive force of the studied two-layer material vary monotonically over the entire range of elastic-plastic biaxial deformation and can be used as an informative parameter for assessing the it’s stresses and deformations.

تصميم متحكم المنطق الضبابي لتتبع أقصى نقطة قدرة لنظام الطاقة الكهروضوئية

This research paper presents the method of fuzzy logic system to optimize the energy extraction in a photovoltaic (PV) power system. The maximum power of a (PV) module varies due to changing temperature, solar radiation, and load. To maximize efficiency, PV systems use a maximum power point tracker (MPPT) to constantly extract the highest power that can be produced by a solar panel and then deliver it to the load. The general structure of an (MPPT) system contains a (DC-DC) converter (an electronic device that converts a source of direct current DC from one voltage level to another) and a controller. The (MPPT) finds and maintains operations at the maximum power point using a tracking algorithm during variations in weather conditions. Because of the nonlinear behavior of (PV) module current-voltage characteristics and the nonlinearity of (DC-DC) converters due to switching, conventional controllers are unable to provide the best response, especially when dealing with wide parameter variations and line transients. The goal of this work is to design andimplement a maximum power point tracker that uses a fuzzy logic control algorithm. Fuzzy logic naturally provides a superior controller for this type of nonlinear application. This method also benefits from the artificial intelligence approach for overcoming the complexity in modeling nonlinear systems. In order to succeed in this work, an (MPPT) system consisting of a (PV) module, a (DC-DC) converter, and a fuzzy logic controller is designed and simulated in Simulink. Analyses of buck- boost converter characteristics are carried out to find the most suitable topology for the PV system used. An integrated model of the PV module with the identified converter is simulated in MATLAB to derive the expert knowledge needed to formulate and tune the fuzzy logic controller. The simulation results show that, the fuzzy logic controller is able to obtain the desired outcomes which are actual power generation of solar panels at different irradiance and temperature. Keywords: Fuzzy logic, PV, MPPT, DC-DC converter, MATLAB programming

THE INFLUENCE OF CHEMICAL AGENTS ON THE TECHNICAL CHARACTERISTICS AND SAFETY OF PROTECTIVE EQUIPMENT AGAINST ELECTRIC SHOCK

The research project’s primary goals were to develop occupational risk management protocols for people who perform maintenance tasks on electrical installations and, in turn, to develop new work tools designed to protect workers in those installations. The research project’s findings are presented in this paper. In order to check the behaviour of the safety characteristics of the protective equipment material under certain influence of professional risk factors, protective equipment materials were subject to tests. The components of in use or new electro-insulating equipment, were evaluated through sampling. Electro-insulating materials underwent dielectric, mechanical, attrition testing, and chemical agent application. The findings revealed the weakness of some electrical insulating materials whose declared duration of use exceeded five years after commissioning, necessitating the assessment of new technical standards for health and safety workplace.

Effects of representative elementary volume size on three-dimensional pore characteristics for modified granite residual soil

The determination of the Representative Elementary Volume (REV) is vital for comprehending the behavior of soil structural characteristics within the micro-to-macro framework. This study utilizes X-ray computed tomography to provide a detailed microscopic exploration of how waste cement, glass powder, and straw fibers contribute to the reduction of permeability in granite residual soils. Based on the pore reconstruction analysis of soil samples, the effect of REV size on the three-dimensional pore characteristics of modified granite residual soil is extensively studied. The results indicate that varying sizes of REV greatly affect the pore structure, porosity, fractal dimension, and permeability. Specifically, as the REV size increases, these parameters initially exhibit fluctuations characterized by uncertainty, ultimately stabilizing at a threshold value of 5000 μm. The incorporation of glass powder and straw fibers enhances the compactness of the soil while reducing the average diameter of connected pores. The alteration in the frequency distribution of connected pores redefines flow pathways, disrupting the preferential channels originally provided by larger pores, which is a primary factor that leads to the reduced permeability of the modified soil. These findings offer valuable references for determining the REV in modified soils, aiding future research in effectively saving time and computational costs.

Social Identity and Voting Behavior in a Deeply Divided Society: The Case of Israel

This paper examines what best explains political behavior in a deeply divided society. Despite the democratic nature of the Israeli political system, we suggest that Israel’s society is characterized by social affiliations mainly defined by social identity that include race, ethnicity, and religion and amount to tribalism. Based on the results of the 2020 election, we examined whether these social affiliations or other socioeconomic characteristics better explain voting behavior. First, we found a significant correlation between tribalism and voting behavior in Israel and socioeconomic characteristics and voting behavior in Israel. When comparing tribalism’s correlation versus other socioeconomic characteristics, we found that the correlation between tribalism and voting behavior in Israel trumps the correlation between socioeconomic characteristics and voting behavior in Israel, except for the Ashkenazi Jews. In other words, voting behavior is better explained by affiliation to the social group, that is, by kinship, race, ethnicity, and religion, than by other socioeconomic characteristics such as education level, economic status, or geographic location. This extends the idea of “in-group favoritism”.

Framework for charged compact objects admitting conformal motion in higher dimension.

We propose a new framework for spherical charged compact objects admitting conformal motion in five-dimensional spacetime. The outer spacetime is considered as Reissner-Nordström to obtain matching conditions. The behavior of model characteristics like stress, pressure, and surface tension for the specific density profile is investigated by using Einstein's Maxwell field equations in a five-dimensional framework. For the proposed solution, all physical parameters behave very well even for variations in electric charge parameters. The existence of charged compact stars is also predicted by this study.

Dynamic Effect of Ply Angle and Fiber Orientation on Composite Plates

Composite materials have revolutionized industries such as aerospace and automotive with their impressive strength-to-weight ratios and customizable properties. Ply angle and fiber orientation are critical factors that significantly impact the dynamic behavior of composite structures, influencing stiffness, strength, and vibrational characteristics. This research delves into the dynamic characteristics of composite plates, explicitly examining how ply angle and fiber orientation affect vibrational behavior. Through finite element analysis (FEA), composite plates with varying ply angles and fiber orientations were modeled to understand their influence on natural frequencies, mode shapes, and dynamic responses under various loading conditions. The study reveals that cross-ply [0/0/0/0] exhibits the highest stiffness and superior stress handling, while the cross-ply balanced laminate [90/0/0/90] demonstrates better vibrational characteristics. The findings highlight the intricate relationships between design parameters and structural vibrational behavior, offering opportunities for optimizing composite structures. Additionally, harmonic analysis showed that a cut-out increases the natural frequency. The results underscore the importance of optimizing composite plate configurations to enhance vibrational characteristics and align natural frequencies with operational requirements, thereby mitigating resonance-related issues.

Sex Differences and Parent-Teacher Discrepancies in Reports of Autism Traits: Evidence for Camouflaging in a School Setting.

The purpose of this study was to examine sex differences and informant discrepancies in parent- and teacher-reports of autism traits. Data were drawn from the Simons Simplex Collection to create a sex-matched sample of autistic youth (N = 388; 4-17years). Included participants had both parent and teacher reports of autistic traits from the Social Responsiveness Scale (SRS). Within each sex group, parent and teacher raw SRS scores were compared. Scores within each informant group (parent/teacher) was assessed for sex differences. Predictors of parent-teacher discrepancies were examined. Despite no sex differences in parent-reported autistic traits, teachers reported males as having more autistic traits compared to females. Parents of females reported significantly more autistic traits than teachers across multiple domains. Being older and female were significant predictors of increased parent-teacher discrepancy for multiple domains. These results suggest discrepancies between the observed autistic traits for females at home and school and builds on the growing body of literature highlighting potential camouflaging across development in autistic youth: parent-teacher discrepancies may reflect ways that autistic females are overlooked by teachers due to conscious changes in behavior or gender-based expectations of female characteristics. Discussion of discrepancies on an individual basis may therefore alleviate potential long-term consequences of camouflaging.

Spatiotemporal analysis of multi-scale cell structure in spheroid culture reveals hypertrophic chondrocyte differentiation

3D cell culture has emerged as a promising approach to replicate the complex behaviors of cells within living organisms. This study aims to analyze spatiotemporal behavior of the morphological characteristics of cell structure at multiscale in 3D scaffold-free spheroids using chondrogenic progenitor ATDC5 cells. Over a 14-day culture period, it exhibited cell hypertrophy in the spheroids regarding cellular and nuclear size as well as changes in morphology. Moreover, biological analysis indicated a signification up-regulation of normal chondrocyte as well as hypertrophic chondrocyte markers, suggesting early hypertrophic chondrocyte differentiation. Cell nuclei underwent changes in volume, sphericity, and distribution in spheroid over time, indicating alterations in chromatin organization. The ratio of chromatin condensation volume to cell nuclear volume decreased as the cell nuclei enlarged, potentially signifying changes in chromatin state during hypertrophic chondrocyte differentiation. Our image analysis techniques in this present study enabled detailed morphological measurement of cell structure at multi-scale, which can be applied to various 3D culture models for in-depth investigation.

Revealing spatial-temporal impact of industrial effluent towards DOM in Riverine employing PARAFAC and MW-2D COS

Industrial activities often disrupt the natural equilibrium of water bodies, with discharged wastewater introducing dissolved organic matter (DOM) and pollutants. This study investigated the water quality along a riverine system subjected to heavy industrial influence by collecting samples from distinct points at before, during, and after industrial discharge across four seasons. By employing EEM-PARAFAC, four fluorescent components were identified at the discharge point including C1 (microbial/ terrestrial humic-like), C2 (anthropogenic humic-like materials), C3 (microbial humic-like), and C4 (wastewater/nutrient enrichment tracer). Specifically, C2 and C4 which contained wastewater and anthropogenic-like material are not found at the pre-pollutant point. Additionally, fluorescence characteristics parameters such as FI, HIX, and BIX are analyzed. Kernel Principal Component Analysis was employed to elucidate the non-linear relationships inherent in the data that able to covered up to 97 % of the data variance, offering nuanced insights into complex behavior of water characteristics across seasonal variations. Two-dimensional correlation spectroscopy (2D-COS) was further employed to evaluate the sequence variation of DOM components and further identify the temporal effect across season with moving window 2D-COS. The sequence order of the DOM fractions was identified as C2→C4→C1→C3 by following the Noda’s rule. In order to understand the interactions between the water characteristics and the DOM components, an empirical polynomial regression model is developed with an average MAPE of 2.2 %. The interaction between DOM-related parameters was identified using structural equation modeling. These findings underscore the dynamic nature of DOM composition under industrial influences considering the spatial-temporal impact.

Scale-dependent behavior of microstructure characteristics of laser powder bed fused TiB2/AlSi10Mg composite

The pre-alloyed TiB2/AlSi10Mg composite, a new high-strength aluminum alloy developed for laser powder bed fusion (LPBF) technology, offers promising applications in lightweight and multi-scaled structures. However, thermal behavior during LPBF is markedly scale-dependent, leading to microstructural variations that significantly affect the load-bearing capacity of multi-scaled structures. Therefore, this study systematically investigates the scale-dependent behavior of microstructure characteristics of this composite. Utilizing a hatching scanning strategy, it was found that the marginal zones of samples are predominantly composed of coarse Al cell and Al grain structures, contrasting with the fine microstructures in the central zones. With increasing structure scale, cell and grain structures in both the marginal and central zones become more refined, with cell sizes reducing by 49 %–72 % (∼3.02 µm → 0.86–1.55 µm). Particularly, the minimum-scaled structures also feature broken eutectic Si particles and nanopores. The essence is primarily due to the low heat dissipation with higher peak temperature and longer duration time at high temperatures in both the small-scale structures and marginal zones. Additionally, smaller structures correlate with reduced microhardness and tensile strength, accompanied by the “softening” of the marginal zones. The strength of the minimum-scaled structure is only half that of the standard sample. Our findings suggest a scale threshold of 2.0 mm for researching scale effect. Encouragingly, incorporating additional contour scanning significantly counteracts the adverse influence of the scale effect. Owing to the combined influence of extended inter-layer time and laser remelting, all samples demonstrate a distinctly refined microstructure. This results in consistently high levels of microhardness and strength, with the “hardening” of the marginal zones. Eventually, the relationship between mechanical properties and microstructure sizes is established. This study provides valuable insights into the innovative designs and engineering applications of multi-scaled structures in LPBF using various materials.

Asymmetry in Polymer-Solvent Interactions Yields Complex Thermoresponsive Behavior.

We introduce a lattice framework that incorporates elements of Flory-Huggins solution theory and the q-state Potts model to study the phase behavior of polymer solutions and single-chain conformational characteristics. Without empirically introducing temperature-dependent interaction parameters, standard Flory-Huggins theory describes systems that are either homogeneous across temperatures or exhibit upper critical solution temperatures. The proposed Flory-Huggins-Potts framework extends these capabilities by predicting lower critical solution temperatures, miscibility loops, and hourglass-shaped spinodal curves. We particularly show that including orientation-dependent interactions, specifically between monomer segments and solvent particles, is alone sufficient to observe such phase behavior. Signatures of emergent phase behavior are found in single-chain Monte Carlo simulations, which display heating- and cooling-induced coil-globule transitions linked to energy fluctuations. The framework also capably describes a range of experimental systems. Importantly, and by contrast to many prior theoretical approaches, the framework does not employ any temperature- or composition-dependent parameters. This work provides new insights regarding the microscopic physics that underpin complex thermoresponsive behavior in polymers.

Experimental Investigation on Self Curing High Performance Concrete

Proper curing of concrete structures is important to ensure that they meet their intended performance and ductility requirements. Therefore an effective in situ curing is necessary to maximize the degree of hydration and to minimize cracking problems due to drying shrinkage. Traditional external curing could not achieve a desired effect due to very low permeability and high chemical reaction in high-performance concrete. So some researches shifted their attention to self curing, a new curing method that may greatly enhance the curing effect on high performance concrete. Super Absorbent Polymers (SAP) are used as self curing agent. SAPs are a group of polymeric materials that have the ability to absorb and retain a significant amount of liquid from their surroundings and to retain the liquid within their structure without dissolving. In this study investigate experimentally and analytically the behavior of exterior beam-column joint and strength characteristics of Self Curing high performance Concrete (SCC) containing Super Absorbent Polymers (SAP) and Silica Fume. In this investigation SCHPC was made by replacement of cement by 10% of Silica fume and Super Absorbent Polymer (SAP) added at a various range of 0%, 0.2%, 0.3%, and 0.4% of cement. The experimental results were then compared with analytical results obtained from the FEM Analysis using ANSYS 14.0. Load Deflection characteristics, Stiffness, Ductility were studied and it is found that the SCHPC has shown good improvement in load caring capacity. Mechanical characteristics like Compressive strength, Split-tensile strength, Flexural strength and Modulus of Elasticity examined. A mathematical model was conducted using SPSS software for the mechanical characteristics of SCHPC.A comparative study between the results obtained from the laboratory and SPSS has been made. The predicted mathematical model for mechanical characteristics produced accurate results for the respective ages when compared with the experimental results. Also, the durability study for Self cuing concrete after 28 and 56 days curing was done by conducting the tests such as saturated water absorption, porosity, Acid resistance, Sea water resistance, Accelerated electrolytic corrosion and Modified sorptivity.

Peculiarities of the electronic properties in the intrinsic magnetic topological insulator MnBi2Te4

The electrical conductivity σ0(T) of single-crystal and polycrystalline samples of the intrinsic magnetic topological insulator MnBi2Te4 was measured in the temperature range from 5 to 300 K. The optical characteristics σ(ω), ɛ1(ω), ɛ2(ω) and R(λ) of MnBi2Te4 were studied in the spectral range from 1250 to 36000 cm−1 at room temperature. The anisotropy of the electrical conductivity of MnBi2Te4 was found, which arises due to the additional contribution from scattering on layer boundaries. The optical spectrum of MnBi2Te4 is formed predominantly due to interband absorption of a light wave. Despite the qualitatively similar behavior of the optical characteristics, there is some difference between poly- and single crystals in infrared region.

Transport Spectroscopy of Donor/Quantum Dot Interactive System in Silicon Nano‐Transistors

AbstractDonor‐atom‐based nano‐devices in silicon represent a breakthrough for individual control of electrons at atomic scale. Here, a finite‐bias characterization of electrical transport through such a device, fabricated on a silicon‐on‐insulator (SOI) wafer with low phosphorus (P) doping, is presented. In this device, multiple quasi‐periodic current peaks are observed at low temperatures in the electrical transfer characteristics. Such behavior of the transport characteristics is generally observed in devices having high doping concentration or with selective doping in the channel region to form a multi‐donor cluster quantum dot. However, in the present device donor–cluster formation is highly improbable owing to low doping concentration. The observed electrical transport characteristics of the device are explained with a model of two non‐interacting donors coupled in series with an unintentionally larger quantum dot, likely formed within the channel due to roughness. Theoretical simulation is also presented here for such a circuit supporting the experimental observations.