Coupled Analysis Research Articles

Performance evaluation of a novel adaptive temperature-controlled lining technology based on thermo-hydro-mechanical coupling analysis

To mitigate the hazards of high geotemperatures in hydraulic tunnels, the performance of a novel adaptive temperature-controlled lining was investigated across various working phases of high geothermal tunnels using the thermo-hydro-mechanical coupling analysis with the finite element software COMSOL. The results indicated an error margin of only 2% to 6% compared to the field measurements, proving the feasibility of the method. Compared with the conventional concrete lining, the adaptive temperature-controlled lining reduced the average inner wall temperature by approximately 55% during construction, decreased the maximum thermal deformation by approximately 37%, transferred the localized energy elevation from the inner wall to the outer lining, and lowered the maximum elastic strain energy density by approximately 62%. During the water-filled operational phase, the radius of temperature influence in the low-temperature zone of the adaptive temperature-controlled lining expanded by approximately 20%, whereas the maximum thermal stress decreased by approximately 76%, the thermal deformation by 50%, and the elastic strain energy density by 88%. Throughout both the construction and operational phases, the adaptive temperature-controlled lining significantly enhanced the temperature control, improved the stress distribution, and reduced the risk of concrete cracking. These findings could offer the innovative engineering insights into the design, construction, and operation of high-geothermal tunnels.

Aerostructural Analysis of a Deployable Aeroshell in Transonic Flow

The deployable aeroshell, a contemporary reentry system, utilizes a thin flexible membrane surface sustained by pressurized gas to efficiently decelerate a reentry vehicle at high altitudes while enabling low-ballistic-coefficient flight. When an in-flight aerodynamic force is applied, the membrane structure undergoes large deformation that may affect its performance. Hence, a coupled analysis that considers the feedback effect of structural deformation is essential for accurately predicting the behavior of such reentry vehicles. In this study, a numerical framework for coupled aeroelastic analysis was constructed in a partitioned manner using open-source software to elucidate the combined effect of structural deformation and compressible flow dynamics and characterize the aerodynamic performance of reentry vehicles with inflatable structures. The results revealed that the membrane surface was deformed elastically by the aerodynamic force owing to the large difference in pressure distribution between the front and back of the aeroshell. Fluctuating behavior was observed in the aerodynamic coefficients owing to the small-amplitude oscillation of the capsule. This oscillation was induced by the large wake behind the vehicle. Several wrinkles and concave-shaped depressions formed on the membrane surface, which exhibited a circumferential movement tendency with time.

Research on coupling analysis and decoupling control of two-degree-of-freedom PTZ system

Abstract With the development of technology, especially in areas such as robotics, aerospace, photography, and videography, gimbal systems, as an important stabilization device, have been widely used. However, the two-degree-of-freedom gimbal system also faces a series of challenges in practical applications. Among them, one of the most critical issues is the internal coupling phenomenon in the system. The coupling phenomenon refers to the mutual influence and a constraint relationship between different degrees of freedom in the system, which may increase the complexity of the system’s dynamic characteristics and make the design and implementation of control strategies difficult. This study aims at explore more advanced and practical decoupling control strategies through in-depth analysis of the coupling characteristics of the two-degree-of-freedom gimbal system, providing new ideas and methods for the further optimization and application of the gimbal system.

Modal Analysis and Optimization of Fluid-Structure Coupling for Rotor and Inner Cylinder of Vertical Condensate Pump

Background: Low-frequency resonance is one of the common issues encountered during the variable-frequency operation of condensate water pumps. There have been numerous patents and papers proposing solutions to address the low-frequency resonance problem in condensate water pumps. However, the solutions for resonance problems often need to be tailored to specific circumstances. Methods: Based on the acoustic method, the dynamic model of the rotor and inner cylinder of Jiangsu Guohua Chenjiagang Power Plant 2B condensate pump is established to compare the difference between dry modal and fluid-structure coupling modal, the influence of perpendicularity, concentricity and bearing wear on the natural frequency of rotor is studied. Results: The rotor is rigid under normal conditions. When the bearing is worn, the frequency of the rotor will be greatly reduced and may fall into the frequency conversion operation range to excite resonance. The deviation of perpendicularity and concentricity will not directly lead to the decrease of rotor modal but will lead to the increase of bearing stress, aggravate bearing wear, and then affect the rotor modal. As the inner cylinder only relies on the fixed support at the top, the structure stiffness is low, which may lead to low-frequency resonance. By adding two support structures at the guide vane, the first-order modal frequency of the inner cylinder can be increased from 3.29 Hz to 28.88 Hz, effectively avoiding the operating frequency range of the system. Conclusion: This study can guide the optimization of similar pump structures.

Moulding of SS316L surgical component using palm-stearin feedstock: Rheological analysis, process window and parametric optimisation

Metal injection moulding of a thin surgical component using a palm-stearin based SS316L feedstock was investigated. The study first determined the optimal solids loading of the feedstock, followed by examining its sensitivity to the shear rate and temperature, to ensure its pseudo-plastic behaviour. After developing the Mouldability index, a process window was established based on the experiments to present appropriate injection parameters. Using the analysis of variance, the significance and mutual coupling of each parameter was evaluated. The study found that the impact of injection speed was greater than other parameters, while holding pressure showed little effect. The verified optimised injection parameters to maximise the green density were found to be an injection temperature of 155 °C, an injection speed of 80 mm/s, a holding pressure of 83 bar, a holding time of 9 s, and an injection pressure of 132 bar, resulting in a green part density of 4.892 g/cm3.

Coupled CFD modeling and thermal analysis of multi-layered insulation structures in liquid hydrogen storage tanks for various vapor-cooled shields

The present study aims to propose a coupled numerical model for analyzing the influence of the configuration of the vapor-cooled shield tubes on insulation performance. The numerical model is developed to calculate the effective thermal conductivity of multi-layer insulation (MLI) and rigorously evaluated. Specifically, the tank evaporation simulation software BoilFAST is manually coupled with the CFD commercial software of ANSYS FLUENT (2020 R2) to accurately determine the mass flow rate and temperature of boil-off gas in a tank, which is then used as inputs for the CFD simulations. This coupling methodology can be used for reliable calculations of boil-off losses for liquid hydrogen and heat transfer inside the MLI structures. Results demonstrate that the estimated effective thermal conductivity agrees with the earlier published data and that increasing the diameter and number of tubes enhances heat exchange between the VCS tubes and MLI structures. Also, the heat flux into the tank is relatively reduced by 32.04 % by increasing the diameter of the tube and 49.14 % by adding the number of tubes. Moreover, the maximum temperature difference of the VCS is estimated to be less than 1 K, indicating nearly uniform distributions of the VCS.

Establishment of Multi-Physics coupling model and analysis on thermal stress and crack risk in directional growth of TiAl alloys under electromagnetic confinement

The electromagnetic confinement directional solidification (EMCDS) technique is an optimal method for preparing large-size and non-contamination directional TiAl alloy crystals. Despite its advantages, the high temperature gradient inherent to this process induces thermal stress within the ingot, which increases the risk of cracking. To address this challenge, an innovative Integrated Multi-Physics Coupling Model was established to map and study the thermal stress field during EMCDS in this study. It synchronized the computation of the electromagnetic field, temperature field, solute field, flow field, and stress field during the crystal growth of TiAl alloy, and its high accuracy was proved by the micro-indentation experiment. Our analysis reveals that transverse temperature differences are crucial in inducing thermal stresses, and identifies that hot cracks and cold cracks are prone to occur respectively at the area of radial 23R along the sample (X = 23R) and on the sample surface, which aligns with experimental observations impressively. This model can more accurately and efficiently optimize the process parameters of the EMCDS process to avoid cracks and promote its industrial application.

Probabilistic and explainable modeling of Phase–Phase Cross-Frequency Coupling patterns in EEG. Application to dyslexia diagnosis

This work explores the intricate neural dynamics associated with dyslexia through the lens of Cross-Frequency Coupling (CFC) analysis applied to electroencephalography (EEG) signals evaluated from 48 seven-year-old Spanish readers from the LEEDUCA research platform. The analysis focuses on CFS (Cross-Frequency phase Synchronization) maps, capturing the interaction between different frequency bands during low-level auditory processing stimuli. Then, making use of Gaussian Mixture Models (GMMs), CFS activations are quantified and classified, offering a compressed representation of EEG activation maps. The study unveils promising results specially at the Theta-Gamma coupling (Area Under the Curve = 0.821), demonstrating the method’s sensitivity to dyslexia-related neural patterns and highlighting potential applications in the early identification of dyslexic individuals.

Spatiotemporal coupling analysis between green total factor productivity and urban e-commerce development in China’s eight urban clusters

The coordinated development of urban e-commerce and green total factor productivity (GTFP) plays a crucial role in achieving high-quality development. This paper selects relevant data from the eight major urban agglomerations in China for research. A model that described the coupling coordination between the regions’ GTFP and urban e-commerce was presented. Then, unfold the spatiotemporal evolution characteristics of their coupling coordination from the “dynamic and static”, “overall and regional” dimensions. The results indicate: (1) The coupling coordination degree between two systems within China’s eight urban agglomerations exhibits an upward trend with fluctuations, transitioning from a state of near dysfunction to good coordination. (2) The spatial heterogeneity in the coupling coordination degree between the two systems in China’s eight major urban agglomerations is evident, with an overall downward trend and exhibiting a “V-shaped” pattern of “decline-rise”.(3) The coupling coordination degree between two systems across China’s eight urban agglomerations exhibits a trend toward centralization, with an amelioration of bipolar differentiation, and a progressive attenuation of spatial heterogeneity.

Mapping the intellectual structure of microfinance and women's empowerment: A bibliometric analysis

The Sustainable Development Goals (SDGs) emphasize promoting and protecting women's rights and privileges. As a result, an increasing body of academic literature describes the various actions taken by different stakeholders to empower women. Amongst the initiatives implemented in many nations, microfinance and financial inclusion programs play a major role. This article aims to present an overview and synthesis of the research on the notion and practices of microfinance and its influence on entrepreneur women's empowerment. In order to do so, this study uses bibliometric techniques over a selection of papers extracted from the Web of Science database, to disentangle the knowledge structure of this academic field. According to our findings, the study of microfinance and women's empowerment is growing, with 470 publications, 963 authors, 67 nations and 36 research areas. Research topics include poverty reduction, gender issues in entrepreneurship, microfinance and women empowerment, and women in microcredit. An additional bibliographic coupling analysis has revealed the hottest research topics, showing the main gaps in the literature that suggest potential directions for future research.

Investigation of Surge Phenomena in a Centrifugal Compressor by 3D-1D Coupling Approach

Abstract Critical instability, such as surge phenomena, can occur at low flow rates for a compressor system, leading to flow rate fluctuations and potential damage. To study this, traditional numerical analysis requires a comprehensive approach encompassing the compressor and its piping system. This demands extensive computational resources and time due to the complexity of capturing internal flow during surge, including separation and vortex generation. To overcome these limitations, this research proposes a computational strategy combining 3D and 1D analysis for enhanced efficiency and reduced computational demands, which employs 1D analysis for more straightforward flow regions like piping and 3D analysis for the more complex compressor section. This approach is facilitated using AMESim for 1D and STAR-CCM+ for 3D simulations, enabling seamless integration and data exchange between different dimensional analyses. The method improves computational efficiency and reasonably approximates surge phenomena compared to experimental data. The 3D and 1D coupled analysis closely aligns with experimental data, providing a viable and more effective alternative method for surge analysis in compressor systems. This methodology promises to streamline the study of compressor surge phenomena, providing a practical tool for engineers and researchers.

Fatigue Crack Propagation Life of Metallic Materials Under Random Loading: A Coupling Analysis Method in the Frequency Domain

ABSTRACTThis paper proposes an equivalent spectrum method to predict the fatigue crack propagation (FCP) life of metallic materials subjected to random loading. To adequately account for the coupling effects between crack propagation and the random response of structures, a coupling analysis model is introduced. The stress intensity factor (SIF) can be estimated based on the power spectral density (PSD) of an equivalent displacement. Random vibration fatigue tests were conducted to evaluate the proposed model on aluminum alloy specimens. Results indicate significant variations in natural frequency with crack length. The predicted results are compared with the experimental values, demonstrating satisfactory prediction accuracy of the proposed coupling analysis model. This model enables the assessment of coupling effects between crack length and random response, facilitating more precise predictions of FCP life in metallic materials and guiding the expanded application of damage tolerance criteria in structural engineering.

Potential and Electro-Mechanical Coupling Analysis of a Novel HTS Maglev System Employing Double-Sided Homopolar Linear Synchronous Motor

Potential and Electro-Mechanical Coupling Analysis of a Novel HTS Maglev System Employing Double-Sided Homopolar Linear Synchronous Motor

Multi-scale modeling: Finite element analysis of the thermophysical properties of carbon/carbon composites considering manufacturing defects and porosity at high temperature

Carbon/carbon (C/C) composites have strict requirements for their thermal properties in extreme environments, especially at high temperature, where their properties are crucial for long-term life. The structure of C/C composites is exceptionally complex and exhibits multi-scale characteristics, and their thermophysical properties are closely related to temperature. Therefore, exploring their thermal response and heat transfer mechanisms through experimental method is relatively costly. This paper constructs a multi-scale finite element model to investigate the influence of structure and manufacturing defects on performance, and analyzes the thermophysical properties of the composites at High-temperature. By constructing a micro-representative volume element (Micro-RVE) that includes fibers, matrix, and pores, and using a steady-state heat transfer analysis method, the influence of material phase distribution on performance is studied. At the same time, a Meso-RVE reflecting the layering form, needle punching effect and manufacturing defects is established, and the transient heat transfer analysis method is used to investigate the influence of the structural form on performance. Finite element analysis shows that, the simulation values of the three C/C composites of unidirectional fiber bundles, short-chopped fiber felts, and needle punched C/C composites show good consistency with the experimental results in the published literature. This paper uses numerical methods to calculate the thermophysical properties of C/C composites from room temperature to 900°C and explores their variation with temperature. The constructed multi-scale model provides an accurate and effective method for predicting the thermophysical properties of C/C composites and also provides new perspectives and insights for thermal-mechanical coupling analysis and structural design.

Exploring Diabetes Research Trends in India: A Comprehensive Bibliometric Analysis Using VOSviewer

Diabetes has become a pressing public health issue in India, prompting the need for a comprehensive understanding of research trends to effectively guide interventions. This study conducted a bibliometric analysis (BA) of diabetes research publications in India spanning from 2014 to 2023 to elucidate the research landscape. Through a systematic literature search using databases, a vast corpus of 498,138 publications was identified, predominantly comprising research and review articles. Temporal analysis of the data revealed a consistent publication output over the years, with a notable increase in recent years, indicating a growing research interest and focus on diabetes-related topics. Keyword analysis shed light on prevalent themes within the literature, such as experimental models and clinical aspects, showcasing the diversity of research focuses within the field. Top-cited articles predominantly addressed clinical studies, suggesting an emphasis on evidence-based research to inform clinical practice and policymaking. Co-authorship networks highlighted collaborative efforts among researchers, with the All India Institute of Medical Sciences emerging as a prominent contributor, reflecting the importance of collaborative research initiatives in tackling complex health challenges. Further analysis through bibliographic coupling and co-citation analysis revealed thematic clusters within the literature, providing insights into specific research areas such as complications and case reviews. These thematic concentrations offer valuable directions for future research and intervention strategies.

Understanding epistatic networks in the B1 β-lactamases through coevolutionary statistical modeling and deep mutational scanning.

Throughout evolution, protein families undergo substantial sequence divergence while preserving structure and function. Although most mutations are deleterious, evolution can explore sequence space via epistatic networks of intramolecular interactions that alleviate the harmful mutations. However, comprehensive analysis of such epistatic networks across protein families remains limited. Thus, we conduct a family wide analysis of the B1 metallo-β-lactamases, combining experiments (deep mutational scanning, DMS) on two distant homologs (NDM-1 and VIM-2) and computational analyses (in silico DMS based on Direct Coupling Analysis, DCA) of 100 homologs. The methods jointly reveal and quantify prevalent epistasis, as ~1/3rd of equivalent mutations are epistatic in DMS. From DCA, half of the positions have a >6.5 fold difference in effective number of tolerated mutations across the entire family. Notably, both methods locate residues with the strongest epistasis in regions of intermediate residue burial, suggesting a balance of residue packing and mutational freedom in forming epistatic networks. We identify entrenched WT residues between NDM-1 and VIM-2 in DMS, which display statistically distinct behaviors in DCA from non-entrenched residues. Entrenched residues are not easily compensated by changes in single nearby interactions, reinforcing existing findings where a complex epistatic network compounds smaller effects from many interacting residues.

Analysis of the load‐bearing characteristics of hydraulic supports for top‐coal caving under the impact of coal and gangue

AbstractTo study the effect of different sizes and speeds of coal gangue falling on hydraulic supports for top‐coal caving discharge hydraulic support on the bearing characteristics of the hydraulic support, the ADAMS hydraulic support rigid‐flexible coupling analysis model was established. HyperMesh is used to flexibly process the hydraulic support, and the column and jack are equivalently replaced by spring damping system. By applying step loads of different sizes and speeds to simulate the impact force generated when the coal gangue falls on different positions of the cover beam, the dynamic response characteristics of the column, balance jack and other articulation points are obtained. Analyses show that: when the impact load is closer to the roof beam, the articulation point of the roof beam‐cover beam and the balancing jack are easy to be damaged. When the same impact load is applied to the cover beam, the faster the load is applied, the hydraulic support column and balancing jack may not be able to absorb and disperse the pressure effectively in time, resulting in the articulation points being subjected to a larger impact force, which is easy to cause damage or destruction. When different sizes and speeds of impact loads are applied to the cover beam, the latter has a greater impact on the dynamic response of the front and rear connecting rod articulation points and the cover beam‐roof beam articulation point than the former, and the hydraulic bracket will be more prone to vibration, deformation, and stress concentration, thus affecting the stability and safety of the bracket. The article is of guiding significance for designing and optimizing the structure and parameters of the hydraulic support, and improving the support performance and stability of the hydraulic support in the comprehensive release working face.

Social Accountability in Medical Education: A Bibliometric Analysis

Social accountability (SA) in medical education is the obligation to direct health professionals’ education to address the priority health needs of communities. Despite the extensive SA-related literature, trends in its prevalence and scope remain unexplained. This study aimed to analyse trends in SA in medical education publications, information clusters and any paucity in integrating SA into medical education. The PubMed and Scopus databases were searched for publications from 1995 to 2023 without language restrictions. VOSviewer was used to conduct the bibliometric analysis. This study retrieved 1,292 articles on SA in medical education, which showed an increasing trend in SA research year by year. The United States (US) had the most publications (512), and the University of British Columbia had the most publications (n = 39). Bibliographic coupling analysis identified five clusters of information related to SA in medical education: SA indicators and medical school accreditation; medical students’ attitudes towards underserved populations; the role of physicians in translating SA into medical education; the impact of socially accountable medical education; and preparing medical students for achieving SA in medical education. The findings demonstrate a rising trend in SA research in medical education. However, collaboration networks were stronger in developed countries, indicating the need to enhance research networks with developing countries. The five clusters of SA-related information could serve as a foundation for future research. The study highlights the importance of investigating obstacles to the adoption of SA in medical education and implementing initiatives to foster its comprehensive integration.

Caprock sealing integrity and key indicators of CO2 geological storage considering the effect of hydraulic-mechanical coupling: X field in the Bohai Bay Basin, China

Caprock sealing efficiency is an essential guarantee for the long-term safety and stability of CO2 geological storage (CCS). However, the uncertainty in the physical and mechanical properties of deep formations poses challenges to accurately predict the risks of CO2 leakage resulting in CO2 breakthrough or caprock fracture. This study aims to address the issue of imperfect key indicators for caprock sealing by focusing on the CCS project in the Bohai Bay Basin, China. A hydraulic-mechanical (HM) coupling program without considering multiphase flow and the chemical reactions is secondary developed based on the finite element software ABAQUS. Furthermore, a three-dimensional finite element numerical model is established for the analysis of HM coupling, with pore pressure increment (∆PP), Coulomb failure stress (∆CFS) and displacement (U) as evaluation criteria. The Tornado analysis and response surface analysis are employed to analyze the impact of 17 indicators on the caprock sealing, including caprock thickness, burial depth, reservoir and caprock permeability parameters, and mechanical parameters. Subsequently, key performance indicators for caprock sealing are determined. The research results indicate that the reservoir permeability, injection rate, caprock permeability, caprock Young's modulus, caprock internal friction angle, caprock Poisson's ratio, and caprock burial depth are key indicators of caprock sealing capability. The reservoir permeability has a greater impact sensitivity compared to the caprock permeability. Pore pressure and displacement increase with increasing in reservoir permeability. The caprock's resistance to deformation and fracturing increases with increasing in Young's modulus and Poisson's ratio of caprock. This study provides valuable insights for evaluating caprock sealing during CO2 storage in saline aquifers.

Measurement and coupling analysis of the efficiency of resource‐based treatment of municipal solid waste in Chengdu–Chongqing area

AbstractMunicipal solid waste (MSW) is crucial for carbon cycle, residents' lives, and green circular economy development, but quantitative research is limited in efficiency and regional synergy. Considering the regional characteristics of Chengdu and Chongqing, this study establishes the input–output indicator system of MSW treatment in 16 cities in the Chengdu–Chongqing area, constructs the Data Envelopment Analysis model and the coupling coordination degree model, and makes an in‐depth study on the efficiency and environmental benefits of MSW resource treatment from 2012 to 2021. The research conclusion is as follows: first, the improvement of MSW treatment efficiency can be enhanced through reasonable policies and measures to promote sustainable urban development and socioeconomic benefits. The input and output levels of MSW treatment in 16 cities all show an upward trend. Second, the 16 MSW treatment systems have good average pure technical efficiency (Chongqing 0.9879, Chengdu 0.9805), average scale efficiency (Nanchong 0.9396), and average comprehensive efficiency (Nanchong 0.9148), but the overall comprehensive efficiency needs improvement. Third, in 2021, Chengdu's ecological and environmental benefits are better than Chongqing's, while Chongqing has a certain degree of input redundancy and output deficiency. Fourth, in the coupling analysis of resource treatment efficiency and environmental improvement benefits in Chengdu and Chongqing between 2012 and 2021, the coordination between resource treatment and environmental improvement in Chengdu lags behind that in Chongqing, but overall, the coupling is improving. Finally, suggestions for improving the efficiency of MSW resource treatment and promoting environmental improvement are presented from the front, middle, and back ends, respectively, to provide a reference for the policy‐making of city managers.