Model Calculations Research Articles

Evaluation of the onset voltage of water adsorption on Pt(111) surface using density functional theory/implicit model calculations

Evaluation of the onset voltage of water adsorption on Pt(111) surface using density functional theory/implicit model calculations

Testing and simulation of the hysteresis characteristics of magnetostrictive materials under harmonic excitation

As various power electronic devices are widely used in the power grid, the current flowing through the drive winding of the magnetostrictive actuator inevitably contains harmonic components. The flux density within the hysteresis material is non-sinusoidal with harmonic components, which distorts the hysteresis characteristics of the material and affects the accurate calculation of losses. This paper builds a harmonic magnetic performance testing platform for magnetostrictive materials to test and analyze the magnetic properties under different excitation conditions (magnetic density amplitude, harmonic order, and harmonic content). To complete the mathematical description of the static hysteresis model containing closed minor hysteresis loops, two pinning coefficients k1(Bn,kTHD) and k2(Bn,kTHD), which are related to the degree of harmonic distortion, are used to express the rate of change of the irreversible magnetization components. Fractional order derivative and harmonic frequency-dependent terms are used to characterize the eddy losses and excess losses mathematically. Finally, the dynamic hysteresis model under harmonic excitation is developed. Comparative analysis of model calculation results and experimental test data shows that the model can not only accurately simulate the distorted hysteresis characteristics but also predict the loss of magnetostrictive materials. This research is of significance to the optimal design and temperature rise analysis of magnetostrictive devices.

Study on the change of the oil-paper insulation’s AC conductivity characteristics based on dielectric response in frequency domain

Oil-immersed power equipment (transformers and high voltage bushings) are key components of power systems. Oil-paper insulation has endured complex and harsh operating conditions when used as a primary insulation system, so it is essential to determine the insulation state of oil-paper insulation system to ensure a stable operation for the power grid. The oil-paper insulation’s conductivity behavior can effectively characterize the degree of insulation deterioration. However, the relationship between the alternating current (AC) and direct current (DC) conductivity behavior for oil-paper insulation systems is still unclear in current research, resulting in limitations in the traditional evaluation model’s application. Therefore, this paper uses oil-paper insulation materials under different aging to carry out relevant research about the changing features of the complex AC conductivity under different test temperature environments. The influence of oil-paper insulation aging, test temperature, and excitation frequency on the complex AC conductivity is verified. Considering the correlation between low-frequency AC conductivity and DC conductivity, the frequency range of AC conductivity is extended by means of frequency temperature and conductance double translation. The temperature dependence of the AC conductivity behavior is defined over a wide frequency test range. The relaxation polarization process dominated the AC conductivity variation law is obtained. The impact of experimental temperature and insulation aging on the cumulative characteristic parameters of AC ionic mobility is clarified. This study theoretically corrects the traditional calculation model for AC conductivity of oil-paper insulation. The bias in conductivity calculations caused by only considering a single relaxation polarization process is eliminated. The conductivity model that can characterize multiple relaxation polarization processes in the dielectric is established. This model provides theoretical support for the later assessment of oil-paper insulation state depending on conductance behavior.

Modelling and optimization of trajectory deviation for compound directional drilling in coal mines

During the sliding mode of compound directional drilling process in coal mines, the inclined angle and azimuth angle need to be changed to minimize the trajectory deviation between the actual trajectory and the designed trajectory. The inclined angle and azimuth angle can be changed by adjusting the tool face angle. In this article, a modelling and optimization method is proposed to obtain optimal tool face angle for sliding mode. Firstly, the gaussian process regression method is employed to build calculation model of trajectory deviation. The optimization model of trajectory deviation consists of the established calculation model of trajectory deviation and the set constraints. Then, the optimal inclination angle and azimuth angle are obtained by solving the constitutive optimization model using an improved particle swarm optimization algorithm. Next, the calculation model of tool face angle is built to represent the relationship between inclination angle, azimuth angle and tool face angle. The optimal tool face angle is calculated based on optimal inclined angle and azimuth angle. Finally, an industrial case study based on the actual drilling data verifies that the proposed method is beneficial to track designed trajectory during drilling process. The proposed method meets the requirements of on-site construction accuracy and ensures the safety and stability of drilling.

Pull-out behavior of glulam connections with glued-in rod loaded parallel to the grain

ABSTRACT Glued-in rod (GiR) is a reliable moment resistant connection method applied in timber structures. To investigate the pull-out performance of GiR connections parallel to the grain in Douglas fir glulam, this article conducted pull-out tests on two types of rods: threaded rods and rebars. The effects of loading condition and anchorage length on the failure mode, pull-out load-carrying capacity, and strain distribution along the anchorage length were studied. The results showed that the specimens suffered four failure modes: bonding failure, yield failure of the steel rod, pull-out failure of the rebar, and splitting failure. The distribution of strain along the anchorage length of the GiR was uneven. The pull-pull specimens exhibited a higher pull-out load-carrying capacity compared to the pull-compression configuration. Additionally, the load-carrying capacity of the GiR connections increased with increasing anchorage length, whereas the average bond strength exhibited a downward trend. Based on test results and existing reference data, a calculation model of the average and standard value of pull-out load-carrying capacity of a single GiR connection parallel to the grain in glulam was proposed.

Scant Evidence for Long-Range Atmospheric Transport of Particle-Bound Benzotriazole Ultraviolet Stabilizers.

Despite benzotriazole UV stabilizers (BT-UVs) being widely used since the 1960s, few empirical data on their atmospheric presence exist. UV-328 was added to the Stockholm Convention on Persistent Organic Pollutants, based in part on model calculations indicating atmospheric long-range transport potential. We investigated the atmospheric occurrence of BT-UVs at multiple sites that differ greatly in their proximity to potential sources. UV-P, UV-328, UV-234, UV-326, UV-329, and UV-327 were quantified in active air samples collected in suburban Toronto, on Saturna Island in the Salish Sea, at Point Petre on Lake Ontario, and in Alert, Nunavut, as well as in XAD-resin based passive air samplers deployed at sites in British Columbia and Quebec. As the most volatile BT-UV, UV-P was present in the gas phase across all sampling locations, with higher concentrations in urban areas. The five less volatile BT-UVs were present only in active air samples from suburban Toronto and were not found above detection limits (0.03-1.7 pg·m-3) anywhere else. Empirical evidence thus does not support model predictions of long-range atmospheric transport of particle-bound BT-UVs. Predictions based on simple model calculations should be supported by empirical data if they are to be used as the basis for regulatory decisions.

Study of proton-induced excitation functions on natGe up to 60 MeV

Abstract The cross sections for the production of medically significant radioisotopes, including 68Ge, 69Ge, 66Ga, 67Ga, 72As and various radioimpurities produced in pure germanium crystal irradiated with 60 MeV protons, were measured. The experiment utilized germanium targets with natural isotopic composition. Irradiation of the targets was performed using a proton beam from the AIC-144 accelerator at the Institute of Nuclear Physics, Polish Academy of Sciences, Krakow. Gamma spectroscopy was conducted with high-purity germanium detectors to measure the gamma-ray emissions from the irradiated targets. This enabled the determination of reaction cross-sections of the produced radionuclides. Additionally, our results were compared with existing literature and TALYS data to validate our findings. Generally, our experimental results align with previous studies, although discrepancies were observed in certain aspects. Specifically, nuclear model calculations and some literature data indicate slightly higher values compared to our findings.

Can charm fluctuation be a better probe to study the QCD critical point?

We study the diffusion properties of an interacting hadron gas and evaluate the diffusion coefficient matrix for the baryon, strange, electric, and charm quantum numbers. For the first time, this study sheds light on the charm current and estimates the diffusion matrix coefficient for the charmed states by treating them as a part of the quasithermalized medium. We explore the diffusion matrix coefficient as a function of temperature and center-of-mass energy. A van der Waals–like interaction is assumed between the hadrons, including attractive and repulsive interactions. The calculation of diffusion coefficients is based on relaxation time approximation to the Boltzmann transport equation. A good agreement with available model calculations is observed in the hadronic limit. To conclude the study, we discuss, with a detailed explanation, that charm fluctuation is expected to be a better tool for probing the QCD critical point. Published by the American Physical Society 2025

Determining the Parameters of Gurson–Tvergaard–Needleman Model for Predicting the Failure of Wrought and Fused Filament Fabricated 17-4 PH Stainless Steel

Abstract Metal additive manufacturing is an emerging technology for creating metallic parts, with metal fused filament fabrication (FFF) rapidly gaining popularity due to its cost-effectiveness. Despite the acceptable mechanical properties of additively manufactured metals using FFF, a significant technical challenge is the presence of undesirable porosity, which affects material performance. This study aims to model the material behavior of FFF 17-4 PH stainless steel, considering its porosity, using the Gurson–Tvergaard–Needleman (GTN) damage model. The GTN model, which incorporates the micromechanical behavior of ductile metals, shows great potential for failure prediction. The GTN model parameters were identified for both wrought and FFF 17-4 PH stainless steel through a series of proposed methods. Initial void volume fractions were determined using density measurements. The evolution of void volume fractions was experimentally assessed through interrupted uniaxial tensile tests, leading to the analytical derivation of three void nucleation parameters based on continuum damage mechanics. Additional GTN model parameters related to material failure were determined through microscopic analysis of rupture surfaces and finite element (FE) trial-and-error methods. FE simulations using the GTN damage model, represented as porous metal plasticity in abaqus, were conducted to verify the identified parameters. The results demonstrated that the numerical calculations of the FE model are in good agreement with the experimental data. The use of experimentally derived GTN model parameters from the proposed methods effectively predicts material behavior, particularly in the post-necking region where traditional FE modeling fails to simulate the realistic material response.

Positional Packet Capture for Anomaly Detection in Multitenant Virtual Networks

ABSTRACTAnomaly detection in multitenant virtual networks presents significant challenges due to the dynamic, ephemeral nature of virtualized environments and the complex traffic patterns they generate. This paper presents a definition of preferable positions within virtual networks to enhance anomaly detection efficacy. Leveraging a combination of overlay and underlay capture positions, this paper examines the strategic impact of network positioning on anomaly detection accuracy, particularly in environments utilizing software‐defined networking (SDN) and network function virtualization (NFV). Through controlled testing with realistic attack scenarios, including data exfiltration, denial of service, and malware infiltration, the advantages and constraints of each capture position are demonstrated. The findings underscore the necessity of adaptable capture mechanisms to address variability in data volume, encapsulation challenges, and privacy concerns unique to virtualized ecosystems. The paper further introduces a cost calculation model that evaluates each capture position by weighting key factors, enabling an optimized trade‐off between detection accuracy and resource efficiency. The derived classification of the positional value significantly improves real‐time detection of both internal and external threats within multitenant networks.

Two-Step Process-Based Open-Circuit Fault Diagnosis for Three-Level NPC Converters

Fast open-circuit (OC) fault diagnosis is essential to ensure that a multilevel inverter operates under stable conditions. Conventional diagnosis methods either require additional hardware sensors or complex calculations. However, these conditions are difficult to realize in some low-cost application scenarios. For this reason, a two-step process-based OC fault diagnosis method is proposed according to available data that can be acquired using the existing sensors in the application. At the same time, the proposed method does not involve complex and precise calculation. By analyzing the effects of an OC fault on the AC-side three-phase current, the faulty bridge arm can be quickly located via the average current. Furthermore, through establishing the calculation model of the neutral point potential, an accurate diagnosis of faulty switching devices can be achieved quickly and easily based on the residuals. The proposed OC fault diagnosis method is also proved to be correct and effective based on simulation and experience.

Multi-Objective Power Supply Restoration in Distribution Networks Based on Graph Calculation and Information Collected by Multi-Source Sensors

With the increasing complexity of the distribution network structure, enhancing the efficiency and reliability during fault restoration has become a focal point. Based on the multi-source information collected by traditional sensors, such as CT and PT, and intelligent sensors, such as D-PMU, and the graph calculation model, the fault recovery problem of a multi-objective distribution network is studied. Firstly, a power flow calculation model and operation constraint adaptable to topology changes are proposed under the graph calculation framework. The minimum spanning tree theory is utilized to define the blackout range and recovery path set. Secondly, the intelligent sensor D-PMU is configured to collect fault information to ensure that at least one of any two connected load vertices is configured with D-PMU. Thirdly, a topological evolution model is established that considers repeated primary and secondary transfer in outage areas while exploring possible recovery strategies deeply. Finally, a distribution network in Shaanxi Province is taken as an example to verify the model. The experiment shows that the strategy in this paper dynamically adjusts the recovery strategy through four means—one transfer, one repeat transfer in the outage area, two transfers, and cutting off part of the outage load—and the overall recovery rate is increased by more than 20%.

Deciphering Financial Strength: Evaluating Urban Cooperative Banks in India through the CAMEL Model

Urban Cooperative Banks (UCBs) are vital to India's banking sector, especially in urban and semi-urban areas. Evaluating their financial performance is essential to understand their economic contribution. This study assesses UCBs' financial performance over a specified period, identifying key indicators and trends influencing their operations. The main objective of this study is to evaluate the financial performance of Urban Cooperative Banks (UCBs) in India from 2020-21 to December 2022. It seeks to identify and quantify key indicators that act as benchmarks for assessing UCB performance. Furthermore, the study utilizes the CAMEL model calculations to analyze these banks' financial frameworks across India. This research employs a quantitative methodology, drawing on data from the Reserve Bank of India (RBI) and Urban Cooperative Banks (UCBs) financial reports. The CAMEL framework is applied to examine the banks' Capital adequacy, Asset quality, Management efficiency, Earnings potential, Liquidity status, Credit flow to agriculture, and asset expansion to assess their financial progress during the defined timeframe. Findings and Results: It sheds light on the bank's ability to withstand economic challenges, adapt to market changes, and capitalise on expansion opportunities, thereby highlighting its long-term sustainability and potential for development in the evolving financial landscape Practical Implications: Here the researchers proposed study offers practical insights for banking associations, policymakers, investors, and stakeholders in the UCB sector. By identifying financial strengths and weaknesses, this research can guide strategic interventions to enhance UCB's stability and growth.

A Global-Scale Overlapping Pixels Calculation Method for Whisk-Broom Payloads with Multi-Module-Staggered Longlinear-Array Detectors

A multi-module staggered (MMS) long-linear-array (LLA) detector is presently recognized as an effective and widely adopted means of improving the field of view (FOV) of in-orbit optical line-array cameras. In particular, in terms of low-orbit whisk-broom payloads, the MMS LLA detector combined with the one-dimensional scanning mirror is capable of achieving both large-swath and high-resolution imaging. However, because of the complexity of the instantaneous relative motion model (IRMM) of the whisk-broom imaging mechanism, it is really difficult to determine and verify the actual numbers of overlapping pixels of adjacent detector sub-module images and consecutive images in the same and opposite scanning directions, which are exceedingly crucial to the instrument design pre-launch as well as the in-orbit geometric quantitative processing and application post-launch. Therefore, in this paper, aiming at addressing the problems above, we propose a global-scale overlapping pixels calculation method based on the IRMM and rigorous geometric positioning model (RGPM) of the whisk-broom payloads with an MMS LLA detector. First, in accordance with the imaging theory and the specific optical–mechanical structure, the RGPM of the whisk-broom payload is constructed and introduced elaborately. Then, we qualitatively analyze the variation tendency of the overlapping pixels of adjacent detector sub-module images with the IRMM of the imaging targets, and establish the associated overlapping pixels calculation model based on the RGPM. And subsequently, the global-scale overlapping pixels calculation models for consecutive images of the same and opposite scanning directions of the whisk-broom payload are also built. Finally, the corresponding verification method is presented in detail. The proposed method is validated using both simulation data and in-orbit payload data from the Thermal Infrared Spectrometer (TIS) of the Sustainable Development Goals Satellite-1 (SDGSAT-1), launched on 5 November 2021, demonstrating its effectiveness and accuracy with overlapping pixel errors of less than 0.3 pixels between sub-modules and less than 0.5 pixels between consecutive scanning images. Generally, this method is suitable and versatile for the other scanning cameras with a MMS LLA detector because of the similarity of the imaging mechanism.

Numerical Simulation and Experimental Study of Piston Rebound Energy Storage Characteristics for Nitrogen-Hydraulic Combined Impact Hammer

The objective of this study is to analyze the piston rebound energy storage characteristics of the nitrogen-hydraulic combined impact hammer and to investigate the manner in which the piston rebound energy is converted and utilized. The kinetic equation of the impact hammer system is established. A numerical calculation model is constructed based on AMEsim, which incorporates the piston, cylinders, reversing valve, accumulator, power source, drill rod, and impacted device. The performance experiment system is designed, the oil pressure experiment and the piston motion experiment are constructed, and the accuracy of the numerical calculation model is verified by comparing the numerical calculation results with the experimental results. This paper investigates the fundamental principles of the piston rebound energy storage and analyzes the relationship between the opening percentage of the reversing valve high-pressure port and the piston rebound energy storage at the outset of the rebound stage. Furthermore, the influence of the length of the piston middle section and the number of high-pressure grooves in the signal chamber on the piston rebound energy storage is investigated. Finally, the experimental comparison allows for an analysis of the influence of the piston rebound energy storage on the performance of the nitrogen-hydraulic combined impact hammer.

Influence of screw angle and position on the extraction dynamics of Cross-Laminated Timber: an empirical analysis and comparative modeling study

ABSTRACT The design of dowel-type fastener connections is crucial for the structural integrity of Cross-Laminated Timber (CLT) systems, with individual fastener anchorage capacity as a key factor. This study investigates the withdrawal performance of Self-Tapping Screws (STSs) in CLT systems using Canadian Douglas fir. Four driving angles—45°, 60°, 75°, and 90°—were tested, alongside screw placements within panel gaps. Optimal performance was observed at 75° and 90°, with 90° placement in gaps enhancing stiffness and ductility but reducing energy dissipation. The ratios of experimental capacities to model predictions were 1.26–1.49 for the Blaß and Uibel (B&U) model and 1.36–1.56 for Eurocode 5 (EC5). The new EC5 code, compared to the previous version, includes several advancements such as more accurate material properties and improved calculation methods for fastener withdrawal capacity, offering enhanced prediction accuracy for STS performance in CLT. The discrepancies in the over-strength factors predicted by the new EC5 version ranged from 1.07 to 1.37. These findings suggest the need to consider the incorporation of a specific calculation model for STS withdrawal capacity in CLT, such as the Ringhofer et al. model, in the next revision of EC5.

Reliability analysis of harmonic drive with multiple failure modes based on improved calculation model of flexspline stress

Reliability analysis of harmonic drive with multiple failure modes based on improved calculation model of flexspline stress

Particle production as a function of charged-particle flattenicity in pp collisions at s=13 TeV

This paper reports the first measurement of the transverse momentum (pT) spectra of primary charged pions, kaons, (anti)protons, and unidentified particles as a function of the charged-particle flattenicity in pp collisions at s=13 TeV. Flattenicity is a novel event shape observable that is measured in the pseudorapidity intervals covered by the V0 detector, 2.8<η<5.1 and −3.7<η<−1.7. According to QCD-inspired phenomenological models, it shows sensitivity to multiparton interactions and is less affected by biases toward larger pT due to local multiplicity fluctuations in the V0 acceptance than multiplicity. The analysis is performed in minimum-bias (MB) as well as in high-multiplicity events up to pT=20 GeV/c. The event selection requires at least one charged particle produced in the pseudorapidity interval |η|<1. The measured pT distributions, average pT, kaon-to-pion and proton-to-pion particle ratios, presented in this paper, are compared to model calculations using 8 based on color strings and EPOS LHC. The modification of the pT-spectral shapes in low-flattenicity events that have large event activity with respect to those measured in MB events develops a pronounced peak at intermediate pT (2<pT<8 GeV/c), and approaches the vicinity of unity at higher pT. The results are qualitatively described by , and they show different behavior than those measured as a function of charged-particle multiplicity based on the V0M estimator. © 2025 CERN, for the ALICE Collaboration 2025 CERN

Efficient automatic estimation of soil constitutive model parameters via particle swarm optimization

Abstract In this study, we automatically estimated the parameters of the modified Cam-Clay model, a representative constitutive model for soil. The estimation was carried out by minimizing the objective function using the dynamic multiswarm particle swarm optimization (DMS-PSO) algorithm, which is an improvement over the original PSO. The objective function was newly defined by quantifying the discrepancy between the targeted results and the model calculations in q-p′-v space. DMS-PSO divides particles into several islands to search globally and prevent local solutions, and even particles that fall into a local solution can be relocated. To evaluate the automatic estimation performance of DMS-PSO, we examined whether model parameters could be correctly estimated from the calculation results (Consideration (1)) and whether the DMS-PSO algorithm could consistently obtain the same parameter values when reproducing the experimental results (Consideration (2)). Regarding Consideration (1), the objective function was consistently smaller than 1.0 × 10–6 when the number of particles was greater than 400 and the number of islands was greater than 40. At this time, the parameter values could be estimated to the fifth decimal place. When two experiments were conducted, the estimation was obtained approximately 1.5 times faster than when only one was conducted. Regarding Consideration (2), the coefficient of variation of the parameters obtained from 100 estimations was at most 1%, and the parameter values were estimated to be approximately the same each time. In addition, narrowing the solution search range based on soil physical properties could reduce the variation in parameters by approximately 10%. Additionally, the parameters could be accurately estimated by data from at least two mechanical experiments.

K-Edge Measurement Technology Simulation Model Design

Abstract Based on the principle of K-edge technology and particle transport theory, the article establishes the calculation model of K-edge measurement technology, which includes key components such as the continuous X-ray light source, high-purity germanium detector, cylindrical sample, collimator, and so on. In terms of light source setting, the light source function was obtained by linear interpolation method according to the X-ray light source model formula; in terms of K-edge absorption distance, the average K-edge absorption distance calculation method was adopted to improve the concentration calculation formula. The calibration factor was obtained under the experimental conditions with 8mm diameter sample bottles. Under identical experimental conditions, the validation was tested out using samples with concentrations of 150g/L and 300g/L. The reconstructed Uranium concentrations were 148.5g/L and 294g/L, with deviations of 1% and 2% between the initial values, respectively. To further validate the correctness of the modified concentration calculation formula, the diameters of the sample bottles were altered to 6mm and 10mm, and the corresponding calibration factors were obtained respectively. Verification experiments were subsequently carried out using solutions with concentrations of 150g/L and 300g/L. The simulation outcomes validate the accuracy of the model and the modified concentration calculation formula. The calculation model constructed in the article combines with actual application scenarios to provide preliminary technical assurance for the expansion and optimization of K-edge measurement technology.