State perception of long-span 10 kV cable lines is one of the critical issues in building intelligent distribution *** twin(DT),which can map the physical status of equipment in real-time,has received extensive ***,tr...
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State perception of long-span 10 kV cable lines is one of the critical issues in building intelligent distribution *** twin(DT),which can map the physical status of equipment in real-time,has received extensive ***,traditional modelling methods cannot meet the requirement of long-span complex DT's real-time computation and *** order to reduce the modelling cost and improve the calculation speed,a modular DT modelling method for cable lines based on real-time temperature field inversion is *** authors develop a modular reduced-order modelling method that applies to long-span 10 kV cable *** with the temperature field inversion,a DT inversion algorithm is proposed to evaluate the transient temperature field and contact resistance inside cable lines,which has been used to evaluate the emergency load ***,temperature rise tests verified the DT inversion algo-rithm's *** operating status of cable lines was evaluated through the modular DT,and the emergency time and emergency ampacity were *** result shows that the new method meets the real-time and high-precision requirements of DT calculation in actual operation *** can be easily extended to cable lines of different voltage levels.
Self and co-regulation of learning (SCRL) are strategies that students can adopt to become more active and committed to their learning. Encouraging students to adopt these strategies is a challenge for teachers that c...
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ISBN:
(纸本)9783031804748;9783031804755
Self and co-regulation of learning (SCRL) are strategies that students can adopt to become more active and committed to their learning. Encouraging students to adopt these strategies is a challenge for teachers that can be met by using narratives as a teaching resource. To support teachers in this process, we present a method for evaluating, classifying, and reflecting on excerpts from immersive narratives for SCRL, so they objectively base their decision-making. The method was developed as an artifact of Design Science Research (DSR). In the Design stage of DSR, a 4-stage scheme was developed, and 38 criteria were described to identify and classify narratives that guide or encourage students to adopt SCRL strategies. In the DSR demonstration stage, we tested the method in an asynchronous e-learning curricular unit in Portuguese higher education, which uses a narrative-oriented immersive learning approach for SCRL, called e-SimProgramming. The results show that the graphic visualization of the classification made it possible to perceive the occurrence of the SCRL categories in the narratives, enabling the teacher to be inspired and reflect on the categories to be enhanced for necessary changes in the narrative in line with their pedagogical objectives.
Effective spatio-temporal measurements of water surface elevation (water waves) in laboratory experiments are essential for scientific and engineering research. Existing techniques are often cumbersome, computationall...
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Effective spatio-temporal measurements of water surface elevation (water waves) in laboratory experiments are essential for scientific and engineering research. Existing techniques are often cumbersome, computationally heavy and generally suffer from limited wavenumber/frequency response. To address this challenge, we propose the Wave (from) Polarized Light Learning (WPLL), a learning based remote sensing method for laboratory implementation, capable of inferring surface elevation and slope maps in high resolution. The method uses the polarization properties of the light reflected from the water surface. The WPLL uses a deep neural network (DNN) model that approximates the water surface slopes from the polarized light intensities. Once trained on simple monochromatic wave trains, the WPLL is capable of producing high-resolution reconstruction of the 2D water surface slopes and elevation in a variety of irregular wave fields. The method's robustness is demonstrated by showcasing its high wavenumber/frequency response, its ability to reconstruct wave fields propagating in arbitrary angles relative to the camera optical axis, and its computational efficiency. This developed methodology is a cost-effective near-real time remote sensing tool for laboratory water surface waves measurements, setting the path for upscaling to open sea application for research, monitoring, and short-time forecasting.
In this paper, a new headspace gas chromatography (HSGC) method has been developed for the determination of ethylene oxide (EO) and 1,4-Dioxane (Dioxane) in bulk lots of polyethylene glycols (PEG). PEG samples are dis...
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In this paper, a new headspace gas chromatography (HSGC) method has been developed for the determination of ethylene oxide (EO) and 1,4-Dioxane (Dioxane) in bulk lots of polyethylene glycols (PEG). PEG samples are dissolved in dimethyl sulfoxide, heated in a headspace oven maintained at 90 degrees C for 10 min and then injected into the GC system for analysis. Analytes are separated through a thermal gradient elution from 36 to 240 degrees C on an Agilent DB-624 column (60 m x 0.53 mm diameter, film thickness 3.00 mu m). The carrier gas is helium and detector is flame ionization detector. Total run time of the new HSGC method is about 18 min. In the new HSGC method, other common residual solvents present in PEGs such as methanol (MeOH), methyl formate (MF) and acetyl aldehyde (Acetal) are also sufficiently separated from EO and Dioxane peaks. In the HSGC methods prescribed in USP monograph <228> and EP monograph <2.4.25>, EO co-elutes with MF. The new HSGC method was successfully validated according to current ICH/VICH guidelines and was found to be specific, linear, accurate, precise, robust and sensitive. This HSGC method is fast and quality control (QC) friendly and suitable for routine analysis for the determination of EO and Dioxane in bulk batches of PEGs in QC laboratories.
In terms of precision, effectiveness and generality, the quantification and propagation of uncertainty for stochastic systems remains a challenge, especially for the estimation of statistical moments for stochastic re...
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In terms of precision, effectiveness and generality, the quantification and propagation of uncertainty for stochastic systems remains a challenge, especially for the estimation of statistical moments for stochastic responses. In this work, a mixed variables-based and vectors-based refined dimension-reduction model is developed to replace a complex response function by component functions that contain both variables and vectors. On the basis of the developed refined dimension reduction model, a new dimension-reduction integration method that takes into account accuracy and efficiency, termed the refined dimension-reduction integration method (RDIM), is put forth as a means of estimating moments of response functions. Two categories of examples, comprising several numerical examples and two engineering examples, are examined to demonstrate the functionality of the proposed RDIM. The findings indicate that the RDIM is adaptable and can maintain a balance between precision and effectiveness for each example.
The thermal diffusivity of magnetocaloric materials has a transition point at a given temperature that depends on the intensity of the applied magnetic field. Consequently, a fine temperature resolution on the materia...
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The thermal diffusivity of magnetocaloric materials has a transition point at a given temperature that depends on the intensity of the applied magnetic field. Consequently, a fine temperature resolution on the material sample is needed to obtain an accurate determination of the thermal diffusivity variation with temperature. The coupling between the external and the internal fields has to be carefully mastered since the pertinent operating condition is fixed by the actual internal field which is not directly measurable and may be heavily affected by any element in contact with the sample. Therefore, contactless methods such as Photo-Thermal Radiometry (PTR) are privileged. The latter is based on a radiative excitation of the front face of a thin sample and the detection of the thermal effect on the opposite face. However, the powerful radiative source may significantly increase the sample temperature which is not suitable for caloric materials. In this work, a low power modulated PTR method is proposed to characterize second order magnetocaloric materials under magnetic field. It was compared to high energy thermo-flash PTR and validated on common materials such as steel and stainless steel, and then applied to gadolinium which is the reference magnetocaloric material for magnetic refrigeration and heat pumping study. The thermal diffusivity of gadolinium samples is measured in the 285.1 K to 305.1 K temperature range, including the magnetic transition temperature without and under an external magnetic flux density of 0.5 T in the 13 mm air gap of the permanent magnet magnetic circuit. The low power probe beam ensures a temperature stability with a negligible sample temperature fluctuation less than 0.05 K on the incident sample surface and less than 0.03 K on the measurement surface. The experimental results without magnetic field align with those using other methods including the magnetic transition temperatures determination. This low-power optical method proved
This paper proposes the fatigue crack growth modelling of three-dimensional geometries with the eXtended Isogeometric Boundary Element method (XIGABEM). The formulation combines the advantages of the dual Boundary Ele...
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This paper proposes the fatigue crack growth modelling of three-dimensional geometries with the eXtended Isogeometric Boundary Element method (XIGABEM). The formulation combines the advantages of the dual Boundary Element method (BEM), the isogeometric approach, and an enrichment strategy for surfaces containing the crack front. The dual BEM approach relies on a boundary-only mesh, eliminating a re-meshing task for internal cracks. The isogeometric approach applies NURBS basis functions to describe both geometry and mechanical fields, allowing accurate representation of curved shapes and improving convergence over classical polynomial functions. The enrichment strategy stems from the Williams expansion of displacements at the crack front, with parameters directly interpolating Stress Intensity Factors (SIFs), removing costly post-processing tasks. The hoop stress criterion and Schollmann criterion are used as crack growth criteria and are combined with a novel least squares strategy to define the updated crack front. Since this study addresses multi-patch discretisation of crack surfaces, additional strategies ensure continuity between patches as required by the enrichment field. Three numerical applications demonstrate the ability of the formulation to model fatigue in curved 3D geometries under various loading conditions, allowing a novel comparison between crack growth criteria.
To investigate the deformation properties of remolded loess subgrade under long-term cyclic dynamic loading,remolded loess specimens compacted via vertical vibration compaction method were produced and some factors in...
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To investigate the deformation properties of remolded loess subgrade under long-term cyclic dynamic loading,remolded loess specimens compacted via vertical vibration compaction method were produced and some factors influencing elastic strain and cumulative plastic strain,which include the number of vibration cycles,depth,and water content,have been investigated.A prediction model for cumulative plastic deformation was *** addition,the collapsible deformation properties of remolded loess were *** indicate that the elastic strain and plastic strain are decreased with increasing vibration cycles and depth and finally tend to be stable when the number of vibration cycles is more than 2000 and the depth exceeds 2.5 *** elastic strain and cumulative plastic strain of compacted loess are increased by 7.2%and 13.0%,respectively,when the water content increases by 1.0%.The cumulative plastic deformation of remolded loess follows a logarithmic *** elastic deformation and cumulative plastic deformation of loess subgrade are far less than the demands for elastic deformation and post-construction settlement of *** the compaction coefficient and water content are increased by 1.0%,the collapsibility coefficient of compacted loess is decreased by an average of 13.7%and 14.5%.Such investigations can prevent subgrade diseases and ensure the safety of subgrade filled with loess soils.
This study proposes an exact analytical approach for investigating the steady-state and transient wave dynamic propagation characteristics in frequency and time domain of rectangular sealed plate with a circular surfa...
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This study proposes an exact analytical approach for investigating the steady-state and transient wave dynamic propagation characteristics in frequency and time domain of rectangular sealed plate with a circular surface crack under anti-plane point source wave dynamic load. By introducing revised factor, a modified multi-directional iterative mirroring method is proposed to address the partial differential governing equations of wave propagation with boundary value conditions. Based on wave function expansion method, the scattering wave function is derived after decoupling the governing equation. Fourier integral expansion method is used to solve the infinite linear algebraic boundary equation composed of boundary value conditions. The accuracy of analytical method is verified by numerical calculation and finite element simulation. The results show that the sealed coupled waves have significant effects on dynamic stress concentration and abrupt displacement change.
A novel explicit phase field generalized interpolation material point method (EPF-GIMPM) is proposed to solve dynamic fracture problems. An explicit rate-dependent phase field fracture model is introduced to ensure lo...
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A novel explicit phase field generalized interpolation material point method (EPF-GIMPM) is proposed to solve dynamic fracture problems. An explicit rate-dependent phase field fracture model is introduced to ensure local growth of the phase field. The proposed method utilizes an explicit forward-difference time integration strategy to solve coupled-field governing equations based on the material point method. Generalized interpolation techniques are employed to improve computational accuracy by eliminating numerical noises from material points crossing cell boundaries during simulation. Additionally, the GIMP technology is combined with a particle-to-particle contact algorithm, and considers Coulomb friction to handle complex multi-body contact and collision fracture problems. Numerical examples, such as cracked square plate tests, Kalthoff-Winkler experiment, collision of rings, and dynamic crack branching, are used to verify the high accuracy and excellent capability of the proposed method while discussing the influence of explicit viscosity parameters on phase field fracture modeling.
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