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Parallel kinematic machines have been applied in aerospace and automotive manufacturing due to their potentials in high speed and high accuracy. However, there exists coupling in parallel kinematic machines, which makes dynamic analysis, rigidity enhancement, and control very complicated. In this article, coupling characteristics of a 5-degree-of-freedom (5-dof) hybrid manipulator are analyzed based on a local index and a global index. First, velocity analysis as well as acceleration analysis of the robot is conducted to provide essential information for dynamic modeling. Then the dynamic model is built based on the principle of virtual work. Whereas the mass matrix is off-diagonal, a local coupling index as well as a global index is defined, based on which coupling characteristics of the robot are analyzed. Results show that distributions of coupling indices are symmetric due to its structural features. And dimensional parameters, structural parameters, as well as mass parameters have a large influence on the system's coupling characteristics. Research conducted in the article is of great help in optimal design and control. Meanwhile, the method proposed in the article can be applied to other types of parallel kinematic machines or hybrid manipulators. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For predesigned high speed permanent magnet machines (HSPMMs), the accurate evaluation of rotor strength is extremely important to ensure the reliability of the rotor at high speeds. This paper mainly addresses a comprehensive study on the rotor stress of one predesigned HSPMM with predetermined dimensions, by considering the effect of the assembly gaps between the segmented PMs and between the PMs and the pole filler, and temperature gradient in the rotor. First, the influence of the assembly gaps for different rotor structures, different PM segments, different pole fillers, different material properties on the rotor stress are summarized by Ansys Workbench. Then, the full investigation on the rotor stress distribution is performed under the influence of the rotor temperature gradient, which is obtained by Ansys-Cfx. And then, by considering the non-isothermal distribution of rotor temperature, the 3D temperature-stress coupling analysis is performed to obtain the optimal sleeve thickness. After fabricating the prototype, continuous operation test is carried out, which validates the effectiveness of aforementioned theoretical analysis. [ABSTRACT FROM AUTHOR]

In this paper, we present a model that is based on near–far-field charged bubble formation and transportation in an underlying dielectric liquid. The bubbles are controlled by the dielectric liquid, which is influenced by an external electrical field. This allows us to control the shape and volume of the bubbles in the dielectric liquid, such as water. These simulations are important to close the gap between the formation of charged bubbles, which is a fine-scale model and their transport in the underlying liquid, which is a coarse-scale model. In the fine-scale model, the formation of the bubbles and their influence of the electric-stress is approached by a near-field model, which is done by the Young–Laplace equation plus additional force-terms. In the coarse-scale model, the transport of the bubbles is approached by a far-field model, which is done with a convection-diffusion equation. The models are coupled with a bubble in cell scheme, which interpolates between the fine and coarse scales of the different models. Such a scale-dependent approach allows us to apply optimal numerical solvers for the different fine and coarse time and space scales and help to foresee the fluctuations of the charged bubbles in the E-field. We discuss the modeling approaches, numerical solver methods and we present the numerical results for the near–far-field bubble formation and transport model in a dielectric carrier fluid. [ABSTRACT FROM AUTHOR]

The complex nonlinearities of hypersonic vehicles can lead to strong couplings between variables, which will bring great challenges to flight control. For this purpose, this paper proposes a novel coupling analysis method for the longitudinal dynamics of a hypersonic vehicle, based on which a coordination controller is designed to reduce the negative effects of the couplings. Initially, according to the coupling characteristics of the hypersonic vehicle, a novel coupling analysis method based on the dynamic equations is proposed to describe the dynamic coupling relationships between variables. Then, a coordination control scheme is designed by combining sliding mode control and the dynamic coupling matrix obtained. Subsequently, the asymptotic stability of the closed-loop system is proved by using Lyapunov theory, and the simulation results are given to verify the effectiveness of the proposed dynamic coupling matrix-based coordination control. [ABSTRACT FROM AUTHOR]

• A 2D acoustic black hole is referenced to the stiffened structures. • The tests of free-field sound radiation and closed cavity sound radiation were conducted. • The acoustic radiation characteristics of the ABH stiffened plate in water is analyzed. Acoustic black hole (ABH) structure, a novel technology for modulating flexural waves, offers promising solutions for controlling noise caused by structural vibrations. In this paper, we introduce acoustic black holes into traditional stiffened plate structures and design a new type of ABH stiffened plate structure, which combines the wave manipulation ability of ABH with the load-bearing capacity of the stiffened structures. We establishes finite element models for calculating the free space sound field and closed cavity sound field of an ABH stiffened plate, builds corresponding experimental platforms, and tests them under point load excitation. The results show that ABH stiffened plate has great vibration and noise reduction effects, with a 5–10 dB reduction in sound radiation power above the cut-on frequency and a maximum noise reduction of about 30 dB. Through quantitative analysis from multiple perspectives, it is shown that ABH have an inherent mechanism of increasing damping level and reducing coupling between structure and sound field. Studying the influence of different media on the acoustic radiation of ABH stiffened plates, results further reveal that ABH have noise reduction effects in water media, and increasing the application scenarios of the ABH stiffened plate structures. [ABSTRACT FROM AUTHOR]

Northeast China is generally experiencing a shrinkage phenomenon similar to that in other old industrial regions worldwide. Large-scale growth-oriented regeneration programs by the government over the long term have led to the decline of social infrastructure in inner cities, thereby causing a structural crisis at the social level, and exacerbating the negative effects of shrinkage. This study investigated Hegang as a typical shrinking city in northeastern China. Coupling analysis was conducted based on network indexes and two categories of social resilience indexes to identify the key social infrastructure that provides residents with resilience to help cope with shrinkage. Our results demonstrate the centralizing effect of large-scale retail sites, and large green spaces and squares on social resilience. We also found that these categories of social infrastructure had effects across different areas of the city, which then provided social resilience to a wider range of residents. Our results also provide evidence for inequalities in the ability of residents to cope with shrinkage. Based on these findings, we characterize China's urban shrinkage and future development trends, and discuss the limitations of the regeneration model that has long been adopted by local governments. We suggest that local governments should consider incorporating investment in resilience to shrinkage into regeneration policies. They should also consider regenerating social infrastructure and deploying funds to a holistic network to build "reservoirs" of social resilience in shrinking cities. In addition, we highlight our methodological contributions and argue that social resilience monitoring should be integrated into China's urban physical examination framework to enhance dynamic planning and the sustainable regeneration capacity of shrinking urban local governments. [Display omitted] • Relationships explored between inequalities in social resilience and the use of social infrastructure. • Resilience to shrinkage provided by small number of key social infrastructure types. • Investment in social resilience should be included in regeneration policies. • Building a "reservoir of social resilience" is effective for coping with shrinkage. [ABSTRACT FROM AUTHOR]

• A new analytical model of BBN-NK combination was constructed. • The model analyzes the coupled risk evolution process of tunnel fires. • The model was validated by curve fitting and residual analysis. • The Boltzmann model was developed. • A BBN-NK-Boltzmann model was constructed to predict tunnel fire probability. One hundred tunnel fire cases worldwide were analyzed, and the key risk factors and maximum risk coupling forms were identified at the system level to improve tunnel safety. The BBN-NK model was introduced to positively analyze tunnel fires. Among the combined model, the BBN model of tunnel fire accident risk coupling was constructed to visualize the risk factor interactions, and the NK model was used for calculation to quantify the coupling degrees of various types of risk factors. Actual statistical data were used for inverse radar data comparison, and nonlinear curve fitting and residual analysis were performed to complete the correction and validation of the integrated BBN-NK model. The forward and reverse analysis deductions form a closed-loop process of the BBN-NK-Boltzmann model. The results show that controlling the coupling of four risk factors, namely human-machine-environment-management coupling, can effectively avoid tunnel fire accidents. Moreover, the typical adverse scenario evolution path and seven key nodes were found to be the key risks that must be considered during prevention and control. With the increase of the coupling factors, the frequency of tunnel fire accidents exhibit an increasing trend, and also conformed to the Boltzmann inversion curve equation. [ABSTRACT FROM AUTHOR]

• Unlike the existing relevant works [12–18], the Fourier series and the singular integral equation method are applied to study a two-dimensional finite initially stressed neo-Hookean solid. Comparing with the mathematical technique of the references [12–18], this technique can study some problems of a finite initially stressed neo-Hookean solid, it can reveal the influence of material edge on stress field. For the singular integral equation method, it can indicate the singularity of stress field clearly and have a better numerical simulation effect than the reference [12]. • Comparing with the boundary conditions of the reference [12–18], the displacement's continuity boundary condition on the crack surface and horizontal displacement's density boundary condition on contact surface is considered. Using displacement's continuity boundary condition on the crack surface can obtain the same results as reference.[12] when the length L of initially stressed neo-Hookean solid tend to +∞. • Comparing with the references [32–33], the singular integral equation of the contact area and the singular integral equations of the cracking tip are solved together. It can reveal the coupling effect of crack and contact better. • For k = 1 and unchanged material property parameters, the incremental stress distribution on the initially stressed neo-Hookean base is very similar to the Cauchy stress distribution of the isotropic linear elastic base. The coupling problem of a cracked neo-Hookean substrate with initial stress under a rigid punch is examined in the current work. Fourier series is used to transform the mixed boundary value problem(MBVP) into singular integral equations (SIEs). The obtained SIEs is solved by using Gauss-Chebyshev collocation method. The stress distributions on the contact zone and crack surface, and related singularities are present. The numerical experiments examine how the punch position, punch width, crack length and propagation parameter affect the stress field. The result showed that: for k = 1 and unchanged material property parameters, the incremental stress distribution on the initially stressed neo-Hookean base is very similar to the Cauchy stress distribution of the isotropic linear elastic base. [ABSTRACT FROM AUTHOR]

Coronary heart disease (CHD) is the leading cause of cardiovascular death. This study aimed to propose an effective method for mining cardiac mechano-electric coupling information and to evaluate its ability to distinguish patients with varying degrees of coronary artery stenosis (VDCAS). Five minutes of electrocardiogram and phonocardiogram signals was collected synchronously from 191 VDCAS patients to construct heartbeat interval (RRI)–systolic time interval (STI), RRI–diastolic time interval (DTI), HR-corrected QT interval (QTcI)–STI, QTcI–DTI, Tpeak–Tend interval (TpeI)–STI, TpeI–DTI, Tpe/QT interval (Tpe/QTI)–STI, and Tpe/QTI–DTI series. Then, the cross sample entropy (XSampEn), cross fuzzy entropy (XFuzzyEn), joint distribution entropy (JDistEn), magnitude-squared coherence function, cross power spectral density, and mutual information were applied to evaluate the coupling of the series. Subsequently, support vector machine recursive feature elimination and XGBoost were utilized for feature selection and classification, respectively. Results showed that the joint analysis of XSampEn, XFuzzyEn, and JDistEn had the best ability to distinguish patients with VDCAS. The classification accuracy of severe CHD—mild-to-moderate CHD group, severe CHD—chest pain and normal coronary angiography (CPNCA) group, and mild-to-moderate CHD—CPNCA group were 0.8043, 0.7659, and 0.7500, respectively. The study indicates that the joint analysis of XSampEn, XFuzzyEn, and JDistEn can effectively capture the cardiac mechano-electric coupling information of patients with VDCAS, which can provide valuable information for clinicians to diagnose CHD.

Cardiovascular diseases are one of the most common causes of death; however, the early detection of patients at high risk of sudden cardiac death (SCD) remains an issue. The aim of this study was to analyze the cardio-vascular couplings based on heart rate variability (HRV) and blood pressure variability (BPV) analyses in order to introduce new indices for noninvasive risk stratification in idiopathic dilated cardiomyopathy patients (IDC). High-resolution electrocardiogram (ECG) and continuous noninvasive blood pressure (BP) signals were recorded in 91 IDC patients and 49 healthy subjects (CON). The patients were stratified by their SCD risk as high risk (IDCHR) when after two years the subject either died or suffered life-threatening complications, and as low risk (IDCLR) when the subject remained stable during this period. Values were extracted from ECG and BP signals, the beat-to-beat interval, and systolic and diastolic blood pressure, and analyzed using the segmented Poincaré plot analysis (SPPA), the high-resolution joint symbolic dynamics (HRJSD) and the normalized short time partial directed coherence methods. Support vector machine (SVM) models were built to classify these patients according to SCD risk. IDCHR patients presented lowered HRV and increased BPV compared to both IDCLR patients and the control subjects, suggesting a decrease in their vagal activity and a compensation of sympathetic activity. Both, the cardio -systolic and -diastolic coupling strength was stronger in high-risk patients when comparing with low-risk patients. The cardio-systolic coupling analysis revealed that the systolic influence on heart rate gets weaker as the risk increases. The SVM IDCLR vs. IDCHR model achieved 98.9% accuracy with an area under the curve (AUC) of 0.96. The IDC and the CON groups obtained 93.6% and 0.94 accuracy and AUC, respectively. To simulate a circumstance in which the original status of the subject is unknown, a cascade model was built fusing the aforementioned models, and achieved 94.4% accuracy. In conclusion, this study introduced a novel method for SCD risk stratification for IDC patients based on new indices from coupling analysis and non-linear HRV and BPV. We have uncovered some of the complex interactions within the autonomic regulation in this type of patient.

Sound ecosystems are a precondition for the sustainable survival and development of human society. However, ecological deterioration caused by socioeconomic activities can result in increasing pressure on ecosystems. Exploration of the spatial interaction between ecosystem and economic development under the background of high-quality and green development is, therefore, necessary. In this study, we analyzed the spatial interaction between the ecosystem services value (ESV) and economic development with the economic and ecological coupling index method based on high-resolution remote-sensing land-use data and socioeconomic statistical data in Hunan Province from 2000 to 2018. The results revealed that the ESV provided by the ecosystems in Hunan Province decreased by US$1256.166 million from 2000 to 2018. The areas with high ESV per unit area were distributed in the mountainous areas, while the areas with low ESV per unit area were distributed in the major cities and their surroundings. The bivariate spatial autocorrelation analysis showed that the ESV had significant spatial dependence on the economic development. In addition, the coupling analysis documented that the relationship between the ESV and economic density was mostly in the low conflict and potential crisis states. These results provide important guidance for the coordinated development of the regional economy and ecosystem conservation.

Acoustic black hole (ABH) structures have been exploited to manipulate the flexural wave propagation with results showing a great potential for structural vibration damping enhancement and suppression of free-field acoustic noise radiation. In the present paper, ABHs are used to reduce the noise inside a cavity bounded by a flexible plate with multiple two-dimensional (2-D) ABH indentations. The interior sound field is generated by and fully coupled to the vibration of the flexible plate subject to a point force excitation. A refined numerical finite element model considering the plate-cavity coupling is established and validated by experiments. Both the simulation and experimental results show a significant noise reduction inside the cavity in a relatively wide frequency range through embedding the 2-D ABHs into the flexible plate. Analyses on the underlying mechanisms show a dual physical process of the ABH effects: the first being the direct consequence of the vibration reduction of the plate as a result of ABH-induced damping enhancement, whilst the second one being caused by a reduction in the coupling strength between the plate and the cavity. This ABH-specific decoupling phenomenon is characterized by the spatial coupling coefficients, which depend on the degree of morphological matching between structural modes and acoustic modes over the plate-cavity interface. The reported phenomenon of the impaired structural-acoustic coupling reveals a new ABH-specific feature which enriches the existing knowledge on ABH structures. [ABSTRACT FROM AUTHOR]

As the inner tube is excited from a rotation frequency at a separation distance, the inner tube will generate a reciprocating screwing motion. In this work, this coupling effect is investigated theoretically. The van der Waals force between two carbon nanotubes is expressed in a simple form of Fourier series so that the coupled nonlinear differential equations can be quickly solved. The proposed approach is thousands of times faster than the traditional method, which makes it possible to fit the coupling coefficients. As a result, expressions for the coefficients of the coupled equations are given. It is observed that a larger initial rotation frequency excitation will result in a higher dissipation rate of the axial oscillation, and vice versa. • Coupling effect of screwing motions of a DWNT was first investigated theoretically. • The proposed approach is thousands of times faster than the traditional method. • Expressions for coefficients of the coupled equations were given. [ABSTRACT FROM AUTHOR]

Cardiovascular diseases are one of the most common causes of death; however, the early detection of patients at high risk of sudden cardiac death (SCD) remains an issue. The aim of this study was to analyze the cardio-vascular couplings based on heart rate variability (HRV) and blood pressure variability (BPV) analyses in order to introduce new indices for noninvasive risk stratification in idiopathic dilated cardiomyopathy patients (IDC). High-resolution electrocardiogram (ECG) and continuous noninvasive blood pressure (BP) signals were recorded in 91 IDC patients and 49 healthy subjects (CON). The patients were stratified by their SCD risk as high risk (IDCHR) when after two years the subject either died or suffered life-threatening complications, and as low risk (IDCLR) when the subject remained stable during this period. Values were extracted from ECG and BP signals, the beat-to-beat interval, and systolic and diastolic blood pressure, and analyzed using the segmented Poincaré plot analysis (SPPA), the high-resolution joint symbolic dynamics (HRJSD) and the normalized short time partial directed coherence methods. Support vector machine (SVM) models were built to classify these patients according to SCD risk. IDCHR patients presented lowered HRV and increased BPV compared to both IDCLR patients and the control subjects, suggesting a decrease in their vagal activity and a compensation of sympathetic activity. Both, the cardio -systolic and -diastolic coupling strength was stronger in high-risk patients when comparing with low-risk patients. The cardio-systolic coupling analysis revealed that the systolic influence on heart rate gets weaker as the risk increases. The SVM IDCLR vs. IDCHR model achieved 98.9% accuracy with an area under the curve (AUC) of 0.96. The IDC and the CON groups obtained 93.6% and 0.94 accuracy and AUC, respectively. To simulate a circumstance in which the original status of the subject is unknown, a cascade model was built fusing the aforementioned models, and achieved 94.4% accuracy. In conclusion, this study introduced a novel method for SCD risk stratification for IDC patients based on new indices from coupling analysis and non-linear HRV and BPV. We have uncovered some of the complex interactions within the autonomic regulation in this type of patient. [ABSTRACT FROM AUTHOR]

In the process of electromagnetic launching (EML), armature-rail contact is affected by the start-up contact. Because the location of the pulse current flowing into the armature is determined by that of the start-up contact region, the distributions of the current and electromagnetic force (EMF) in the armature are affected by the start-up contact. In this paper, the start-up contact between the conventional C-armature and rail is analyzed. Additionally, the distributions of the current flow and EMF in the armature are analyzed. The EMF resulting from the electromagnetic analysis is transferred to the structural analysis via a method of electromagnetic-structure coupling, and the distribution of the armature-rail contact pressure is acquired. Some armature contact parameters and the concept of the armature contact efficiency are proposed. The relationships between the contact parameters and the contact efficiencies of armatures with different lengths are acquired based on a series of simulations. To improve the contact efficiency of the armature, a method called “reverse loading” is presented to design an armature with a new profile. The traditional straight armature is replaced with a curved armature, and the results show that the contact efficiency of the armature with the curved profile is greatly improved. [ABSTRACT FROM AUTHOR]

Highlights • A RELAP5/MELCOR coupling interface was developed to assess the system performance. • The RELAP5 model of a thermosiphon was validated against an experiment of prototypical scale. • The passive cooling system mitigates SBO more easily than LOCA scenario. • Heat removal is impeded when steam circulation is blocked by residual water in LOCA scenario. • It was observed that the passive cooling system is promoting H 2 production in LOCA scenario. Abstract In the aftermath of the Fukushima Daiichi nuclear accident, a great concern has been raised about enhancing the inherent safety of a spent fuel pool (SFP). A passive cooling system using two-phase thermosiphon loops was concerned in this paper. A RELAP5/MELCOR coupling interface was developed, aiming at simultaneously simulating the transient behaviors of the SFP (by MELCOR) and the passive cooling system (by RELAP5). First the RELAP5 model of the thermosiphon loop was qualified against an experiment of a prototypical scale. Comparisons between the experiment and predictions show a good agreement. MELCOR standalone calculations for both station blackout (SBO) and loss of coolant accident (LOCA) without the passive cooling system demonstrate severe degradation of fuel rods. In contrast, for the SBO accident, the coupling simulation shows that the passive cooling system can effectively remove the decay heat, thus keeping fuel rods intact. As for the LOCA scenario, it is more challenging for the passive cooling system due to: (i) the heat transfer power is low during the drainage of water since the natural circulation of steam is blocked by the residual water at the bottom, leading to unavoidable heat-up and oxidation of fuel cladding; (ii) the heat transfer coefficient between steam and the evaporator is very small, which consequently may require a larger heat transfer surface area. Nevertheless, the heat transfer power substantially increases after the pool is emptied and natural circulation is established. The decay heat can be removed by steam convection, thus maintaining the mechanical integrity of fuel rods and stabilizing the fuel temperature eventually. It is also observed that H 2 production is undesirably promoted because the steam supply is enhanced. However such adverse effect can be diminished by increasing the thermosiphon loops number. [ABSTRACT FROM AUTHOR]

For the coupling problems of product family design, the similarities and differences of design coupling between product family and single product were analyzed and compared, and a method of analyzing and disposing coupling design for product family was presented based on axiomatic design and modular incidence matrix. The axiomatic design theory was utilized as framework to analyze and classify functional requirements. The corresponding relationships among customer's demands, functions, components and design parameters of product platform, were analyzed, and the influences of adaptive design parameters were considered to be divided into two categories to identify commonality and differences of product family. This may weaken design coupling from strategic level of platform plan. In the view of platform operation level, according to comprehensive correlation degree among design parameters, any modules were generated by clustering reconstruction with less dependent degree in design structure matrix. The change propagation of design parameters were analyzed, and modular incidence matrix was established. Then from the coupling inside modules, and among design parameters with different modules, the detailed analyzing and disposing method was given. Finally, an example of electro-hydraulic disc brake was provided to illustrate the analysis and disposal processes on the proposed method. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central China Normal University is the property of Huazhong Normal University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights • This work introduces the steering modality into the study of the steering system researches the performances of steering. • The natural frequency of steering system is obtained by Design of Experiments design method and response surface method. • The multi-objective optimization is carried out by PSO and NSGA-II algorithm, respectively. Abstract The steering modality and steering performance are coupled with each other. Thus, how to consider the influence of the steering modality on the steering performance and improve the system's overall performance is significant to the steering system. This work introduces the steering modality into the study of the steering system, and combines the dynamics model with the physical model to research the performance of steering feel, steering sensitivity and steering modality. Based on the dynamic model of the vehicle and steering system, the transfer functions of steering feel, steering sensitivity and steering stability are derived. Moreover, the natural frequency is obtained by combining of design of experiments (DOE) design method and response surface method. Then the optimization mathematical model of the steering system is established and the multi-objective optimization is carried out by particle swarm optimization (PSO) algorithm and non-dominated sorting genetic algorithm II (NSGA-II) respectively. The optimization results show that the steering system optimized by NSGA-II algorithm can better avoid the resonance with the engine at idle condition, and further improve the system's overall performances. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A floating offshore wind turbine (FOWT) experiencing two mooring failure can substantially escalate the risk of persistent damage to the remaining moorings. Industry standards mandate that FOWTs must demonstrate the capability of maintaining self-sustainability even in the occurrence of dual mooring failure. Therefore, it is importance to investigate the dynamic response of wind turbines in the case of two mooring line failure. In this study, a novel coupling method of FAST and AQWA was used to analyze the dynamic response of a 5 MW FOWT installed on a barge platform when two mooring lines fail at the same corner. The time-domain response processes of rated and extreme sea conditions were simulated for different failure time intervals (0s, 60s, and 1500s), and the dynamic response of the platform and the change of mooring line tension at each stage are regularly explored. The results indicate that a shorter interval between two mooring line failures results in a more unstable FOWT state. The center of gravity of the wind turbine presents an irregular spiral trajectory, and the platform response exhibits varying characteristics at each stage of the failure process. The transient effect is smaller as the wind turbine approaches the motion limit state. • In this study, a novel coupling method of FAST and AQWA was used to analyze the dynamic response. • This study explores the cascading effect resulting from the failure of two mooring lines in a floating offshore wind turbine (FOWT). • This study takes into account the wind and wave misalignment. • The time-domain response processes of rated and extreme sea conditions were simulated for different failure time intervals (0s, 60s, and 1500s). [ABSTRACT FROM AUTHOR]

Functional connectivity analysis is gaining more interest due to its promising clinical applications. To study network mechanisms underlying seizure termination and postictal depression, we explore dynamics of interhemispheric functional connectivity near the offset of focal and bilateral seizures in the experimental model of reflex audiogenic epilepsy. In the model, seizures and spreading depression are induced by sound stimulation of genetically predisposed rodents. We characterize temporal evolution of seizure-associated coupling dynamics in the frontoparietal cortex during late ictal, immediate postictal and interictal resting states, using two measures applied to local field potentials recorded in awake epileptic rats. Signals were analyzed with mean phase coherence index in delta (1–4 Hz), theta (4–10 Hz) beta (10–25 Hz) and gamma (25–50 Hz) frequency bands and mutual information function. The study shows that reflex seizures elicit highly dynamic changes in interhemispheric functional coupling with seizure-, region- and frequency-specific patterns of increased and decreased connectivity during late ictal and immediate postictal periods. Also, secondary generalization of recurrent seizures (kindling) is associated with pronounced alterations in resting-state functional connectivity – an early wideband decrease and a subsequent beta-gamma increase. The findings show that intracortical functional connectivity is dynamically modified in response to seizures on short and long timescales, suggesting the existence of activity-dependent plastic network alterations that may promote or prevent seizure propagation within the cortex and underlie postictal behavioral impairments. • Audiogenic seizures change interhemispheric functional coupling (IFC) in the cortex. • Late ictal and postictal IFC shows seizure-, region- and frequency-specific dynamics. • Animals expressing focal cortical seizures show reduced resting-state IFC. • But bilateralization of the seizures is associated with enhanced beta-gamma resting-state IFC. [ABSTRACT FROM AUTHOR]

China faces major challenges of balancing food security and water resources conservation. However, little is known about the space-time interactions of food production and water consumption. To fill in this knowledge gap, this study quantitatively analyzed China's spatial-temporal dynamics in crop production and irrigation water demand (IWD), and decomposed their driving factors using the method of Logarithmic Mean Divisia Index. The results indicated that China's national IWD and crop production had strong space-time correlations over the past decades, and their gravity centers gradually concentrated towards the arid northern regions. These spatial shifts exacerbated the unbalance of water resources and crop production between north and south. Among all the driving factors, planted area contributed the most to the increase in IWD (+88%), followed by irrigation water demand per unit area (+18%) and crop mix (−6%). In particular, the expansion of planted area in water-scarce regions intensified the food-water nexus and aggravated China's water scarcity. Fortunately, this research found that rational optimization of cropping systems could largely mitigate agricultural water consumption without sacrificing food production. These findings provide valuable insights for reducing trade-offs and enhancing synergies between food security and water sustainability. [Display omitted] • China's crop production and irrigation water demand had space-time correlations. • Expansion of planted area in water-scarce regions intensified food-water nexus. • Optimizing cropping system mitigates water consumption without reducing production. [ABSTRACT FROM AUTHOR]

• Investigation into the noise suppression mechanism of an ABH-cavity system under interior acoustic excitation. • Study of the acoustic radiation characteristics of ABH plates at lower frequencies. • Examination of the coupling mechanism between the acoustic space and the ABH plate. • Manipulation of the mapping matrix and variation in the number of ABHs to achieve reduced radiation efficiency of structural panels. The acoustic black hole (ABH) structure exhibits superior vibration and sound radiation control capability compared to its flat counterpart. However, for a coupled plate-cavity system under interior acoustic excitation, the underlying suppression mechanism of noise radiation has not been explored, especially below the critical frequency of the structure. In this paper, the noise suppression mechanism of an ABH-cavity system under interior acoustic excitation is investigated both theoretically and numerically. Based on the theoretical analysis, the noise radiation depends on both the structural modes and the cavity modes, which can be suppressed in two ways. One is to lower the magnitude of structural transfer functions. The other is to change the mapping matrix which maps the structural modal amplitude to the amplitude of radiation modes. For the former, numerical analysis based on FEM demonstrates that a lower structural transfer function is obtained in the ABH-cavity system compared to its flat counterpart because of the damping enhancement characteristic of the ABH structure. Therefore, attenuated flexural vibrations and reduced sound radiation are achieved at corresponding modal frequencies. For the latter, ABH-cavity systems with varying numbers of ABHs are constructed to demonstrate a simple solution of manipulating the mapping matrix to achieve the reduced radiation efficiency of structural panels and the enhanced suppressing effect of noise radiation. The study in this paper indicates a feasible direction for the further optimization analysis of noise radiation suppression of the ABH-cavity system. [ABSTRACT FROM AUTHOR]

In this paper, we present a model that is based on near−far-field charged bubble formation and transportation in an underlying dielectric liquid. The bubbles are controlled by the dielectric liquid, which is influenced by an external electrical field. This allows us to control the shape and volume of the bubbles in the dielectric liquid, such as water. These simulations are important to close the gap between the formation of charged bubbles, which is a fine-scale model and their transport in the underlying liquid, which is a coarse-scale model. In the fine-scale model, the formation of the bubbles and their influence of the electric-stress is approached by a near-field model, which is done by the Young−Laplace equation plus additional force-terms. In the coarse-scale model, the transport of the bubbles is approached by a far-field model, which is done with a convection-diffusion equation. The models are coupled with a bubble in cell scheme, which interpolates between the fine and coarse scales of the different models. Such a scale-dependent approach allows us to apply optimal numerical solvers for the different fine and coarse time and space scales and help to foresee the fluctuations of the charged bubbles in the E-field. We discuss the modeling approaches, numerical solver methods and we present the numerical results for the near−far-field bubble formation and transport model in a dielectric carrier fluid.

A novel temperature computation method of turbine disk is proposed according to theoretical analysis, where the coupling analysis of the outer surface in disk and fluid relative to this outer surface was carried out, instead of the segregation condition (constant wall temperature or constant wall heat flux condition). The selected correlations, numerical and experimental data of the heat transfer coefficient are presented and compared, so are the theoretical and simulated temperature profiles. The results show that: The maximum temperature deviation coefficient (φT) between the theoretical results and simulation data is less than 8.7% while ReΦ = 4.65×105, Cw = 7520, Rem = 5×105. The convective heat transfer coefficient distributions at the disk outer surface exhibited the influence of region A and region B. The convective heat transfer is dominated by the mass flow rate of cooling air in region A, while dominated by the mainstream mass flow rate in region B. The temperature of the turbine disk decreases with the mainstream mass flow rate increasing, especially at the high radius of turbine disk, while the overall temperature of turbine disk decreases with the increase of cooling air mass flow rate. Both the hr and hz increase with the ReΦ increasing, leading to a minor increase in temperature of turbine disk eventually.

For the coupling between modules in product family design, an approach to analysing coupled design for product family based on coupling incidence path and correlation impact degree is presented. The coupling of three cases is discussed, i.e. the coupling between platform modules, between platform module and customisation module, as well as between customisation modules. Then the interface among modules can be identified, and instigating components are considered as controllable factors and experimental design techniques are utilised to analyse their influence on the design objectives. According to analysis on coupling incidence path and correlation impact degree, the implementation sequence of modules is identified and corresponding decoupling strategies are proposed, if any, that may weaken the coupling of product family design. Finally, an example on the trolley design of gantry crane is provided to illustrate the proposed method for coupling analysis and decoupling of association modules in product family design. [ABSTRACT FROM AUTHOR]

Aiming at the problem that a thin-walled plastic part easily produces warpage, an orthogonal experimental method was used for multiparameter coupling analysis, with mold structure parameters and injection molding process parameters considered synthetically. The plastic part deformation under different experiment schemes was comparatively studied, and the key factors affecting the plastic part warpage were analyzed. Then the injection molding process was optimized. The results showed that the important order of the influence factors for the plastic part warpage was packing pressure, packing time, cooling plan, mold temperature, and melt temperature. Among them, packing pressure was the most significant factor. The optimal injection molding process schemes reducing the plastic part warpage were melt temperature (260°C), mold temperature (60°C), packing pressure (150 MPa), packing time (2 s), and cooling plan 3. In this situation, the forming plate flatness was better. [ABSTRACT FROM AUTHOR]

While previous studies have focused on window operation in residential buildings and small-scale offices, typical window operation behavior in an open-plan office is studied here. Unlike single offices, open-plan offices accommodate more people at once, which leads to more complex window operating behavior. An open-plan office located in Nanjing, Jiangsu Province was studied. Questionnaires and field measurements were adopted to determine factors influencing window operating behavior. Differences between subjective and objective feedback were detected in this study. Three typical window operating patterns were classified under the influence of outdoor temperature. The distribution of the “windows open state” with changes in outdoor temperature was polynomial. Through coupling analysis of environmental and non-environmental factors, it was found that window operating behavior in the open-plan office was influenced by the outdoor temperature, the daily work schedule of occupants, and the state of air conditioners. [ABSTRACT FROM AUTHOR]

The temperature of axial-flux permanent magnet couplers was analyzed using the electromagnetic-thermal coupling method. On the basis of analytical magnetic field calculation， a magnetic field analytical model of the axial-flux permanent magnet couplers was presented to derive the eddy current loss formula. The thermal resistance and heat transfer coefficient were calculated， and a thermal model of axial-flux permanent magnet couplers was established by taking the eddy current loss as the heat source. The electromagnetic-thermal coupling method was analyzed to predict the effect of various loads on eddy current loss and copper plate temperature rise. The analytical results compared with the finite element results showed that the magnetic field analytical model and the thermal model of axial-flux permanent magnet couplers using electromagnetic-thermal coupling method could predict the eddy current loss and the copper plate temperature rise reasonably and quickly. [ABSTRACT FROM AUTHOR]

At hypersonic speed, strong nonlinear couplings will bring enormous challenges to the attitude control of a hypersonic flight vehicle. To reduce the negative impacts of the couplings, a hierarchical coordinated controller is proposed for a generic hypersonic vehicle in this paper. By using a statistical sampling method, a series of coupling analyses between any two different attitude variables groups are studied firstly, and the matrices that describe the coupling degrees are provided. Based on the coupling degree matrices, two coordinated controllers are designed for the attitude angles and angular rates, respectively. The simulation results indicate that the proposed controller can effectively coordinate the coupling impacts, and achieve smooth attitude tracking. [ABSTRACT FROM AUTHOR]

The goaf stress recovery under the effect of overlying strata subsidence has notable effect on mining-induced stress field. Based on the coupling effect between ground stress and goaf compression，the mechanical characteristics and properties back-analysis method of caved rock are studied，the tension-weakening characteristics of rock mass in fractured zone are analyzed，and hereby the coupling simulation method between mining-induced stress and goaf compression is proposed and verified using a simulation case study. The results show that the mechanical behavior of the compressed caved zone follows an exponential growth，the compression stiffness nonlinearly increases with the compression strain. The mechanical properties of caved zone obtained from back-analysis agree with the analytical results，which contribute to the simulation of the mechanical behavior of goaf. The tension-weakening model，which is developed from strain-softening model by adding the tension-weakening algorithm，can describe the weakening of Young's modulus，hereby achieve to describe the mechanical behavior of fractured rock mass rigorously. Based on the mechanical behavior simulation of caved and fractured zone，the proposed method can conduct the coupling numerical simulation of mining-induced stress field and the overlying “two-zone”. [ABSTRACT FROM AUTHOR]

Piezoelectric micro-jets are based on piezoelectric ink-jet technology and can achieve the drop-on demand requirements. A piezoelectric micro-jet which is designed for bearing lubrication is presented in this paper. In order to analyze the fluid dynamic characteristics of the piezoelectric micro-jet so as to obtain good injection performance, a direct coupling simulation method is proposed in this paper. The effects of inlet and viscous losses in the cavity are taken into account, which are close to the actual conditions in the direct coupling method. The effects of the pulse excitation parameters on the pinch-off time, tail length, velocity, and volume of the droplet are analyzed by the proposed direct coupling method. The pressure distribution inside the cavity of the micro-jet and the status of the droplet formation at different times are also given. In addition, the method is proved to be effective in predicting and analyzing the fluid dynamic characteristics of piezoelectric micro-jets by comparing the simulation results with the experimental results. [ABSTRACT FROM AUTHOR]

False monitoring information is a major problem in process production system and several ineffective methods have been proposed to identify false monitoring information in the production system. In this paper, a new method is proposed to identify false monitoring information based on system coupling analysis and collision detection from the perspective of data analysis. Coupling multifractal features are extracted to reflect the changes in coupling relationship by utilizing the multifractal detrended cross-correlation analysis (MF-DXA). Each monitoring variable in process production system has more than one coupled variable, which can be regarded as multi-source. To achieve low redundancy in features and uniform description of coupling relationship, the feature level information fusion is studied based on modified Mahalanobis Taguchi system (MTS). False alarms are identified when the coupling relationships among the coupled monitoring variables collide. Analysis results of coupled Rössler and Henon datasets indicate the feasibility of this method for selecting the effective coupling feature and uniform description of coupling relationship. The compressor system case of Coal Chemical Ltd. Group is studied and false monitoring information is identified. [ABSTRACT FROM AUTHOR]