In several epidemic diseases, one of the main symptoms exhibited by people is abnormal body temperature. Therefore, monitoring body temperature is crucial for preventing the spread of infectious diseases and facilitat...
In several epidemic diseases, one of the main symptoms exhibited by people is abnormal body temperature. Therefore, monitoring body temperature is crucial for preventing the spread of infectious diseases and facilitating timely responses. This study presents a wearable bracelet that can be used as a temperature monitoring and trajectory analysis system. The temperature sensor in the bracelet can effectively monitor the body temperature of the wearer in the target scene, and the data transmission between the bracelet and the data collector can effectively detect the movement range and trajectory of the wearer. Through these, the whole set can also detect the direct and indirect contact of the wearer in any period of time, which is very helpful for the prevention and control of infectious diseases and the isolation of potentially infected persons.
In this work, the synergetic effect of coating properties and fibrous architecture on the evolution of thermal stress was studied by finite element simulation. The numerical implementation was conducted on the plain-w...
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In this work, the synergetic effect of coating properties and fibrous architecture on the evolution of thermal stress was studied by finite element simulation. The numerical implementation was conducted on the plain-woven ceramic matrix composites coated with environmental barrier coatings (EBCs). Within the simulations, the microstructure of both coating layer and composite substrate was precisely modeled. The distributions of thermal residual stress of different yarn waviness and layer properties were simulated and compared. Their synergetic effect on the evolution of stress was then investigated by comparing the simulated results under different mechanical loadings which can enlarge the nonuniform distribution of stress induced by fibrous architecture. The results show that the cooling process causes considerable thermal residual stress in each layer of a Si/mullite/Yb2Si2O7 EBCs. Similar to the layer properties of coatings, the fibrous architecture of the composite substrate also plays an important role in the stress distribution in the coatings. Thus, it can be concluded that an adequate prediction of the local stress distribution and the failure modes for the EBCs requires a realistic representation of fibrous architecture as well as the coating layers. The former is usually ignored in the previous studies.
The current study presents a micromechanical methodology to analyze the cracking behavior of a SiC/SiC composite with multilayer interphase using finite element method. To capture the constituent level damage initiati...
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The current study presents a micromechanical methodology to analyze the cracking behavior of a SiC/SiC composite with multilayer interphase using finite element method. To capture the constituent level damage initiation and propagation within the multilayer interphase, an axisymmetric unit-cell model was developed by discreetly modeling the fiber, the matrix, and the sublayers of interphase. Moreover, the cracking inside the interphase and debonding at the interfaces between different constituents were taken into account. The extended finite element method (XFEM) was applied to model the cracking inside the interphase and matrix. The cohesive surface approach was employed to describe the debonding behavior at all the interfaces. Adopting the proposed numerical approach, detailed local stress state and cracking behavior of SiC/SiC composites with multilayer interphase were analyzed. The results show that the multilayer interphase has a significant effect on the cracking behavior. Moreover, the growth length of secondary cracks had been demonstrated to be a useful parameter that is capable of connecting composites level behaviors and constituent level damages. From the various numerical methods used, the finite element simulation in conjunction with the XFEM and the cohesive surface approach is a precise and consistent way to analyze the crack propagation and prediction of failure for composites with multilayer interphase. The research provides a fundamental method for promoting the interphase design of SiC/SiC composites.
In this paper, a flexible plasma jet source with newly designed needle -shaped protrusion (NSP) electrode capable of producing flexible atmospheric brush -like microplasma jet (FB mu PJ) was developed and its applicat...
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In this paper, a flexible plasma jet source with newly designed needle -shaped protrusion (NSP) electrode capable of producing flexible atmospheric brush -like microplasma jet (FB mu PJ) was developed and its application for internal surface treatment was investigated. The generator could maintain flexibility while possessing a certain degree of rigidity. Simulation and experimental results indicate that FB mu PJ with NSP electrode was more efficient in generating the brush -like microplasma jets compared to conventional wire electrodes. The electrical characteristics showed that the discharge of this novel plasma source was a typical dielectric barrier discharge, and diverse oxygen -containing reactive species favorable for material surface treatment were observed. The internal surface of the silicone tube would get rougher and grafted with polar oxygen -containing functional groups after plasma treatment, and the inner surface can be transformed from hydrophobic to hydrophilic. Finally, the interfacial adhesion of the silicone tubes can be effectively enhanced by FB mu PJ.
This article investigates the problem of designing H-infinity dynamic output feedback reliable controller for discrete-time Markov jump nonlinear systems with persistent dwell-time switched transition probabilities ba...
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This article investigates the problem of designing H-infinity dynamic output feedback reliable controller for discrete-time Markov jump nonlinear systems with persistent dwell-time switched transition probabilities based on the Tagaki-Sugeno fuzzy model. The uncertainty of measurement output, which is assumed to occur randomly, and mode-dependent actuator faults are considered simultaneously. Moreover, the jumping property presented by system modes is described by the Markov chain of which transition probabilities are considered to be piecewise time-varying, and is described by adopting the more flexible persistent dwell-time switching rule. Based on the stochastic analysis approach and Lyapunov stability theory, some sufficient conditions are established to ensure the resulting closed-loop system being mean-square exponentially stable with the prescribed H-infinity performance. Furthermore, the desired controller gains can be obtained through solving a convex optimization problem. Finally, the practicability and availability of the proposed control method are illustrated by a numerical example and a modified tunnel diode circuit model.
This article investigates the problem of designing $\mathcal {H}_{\infty }$ dynamic output feedback reliable controller for discrete-time Markov jump nonlinear systems with persistent dwell-time switched transition ...
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This article investigates the problem of designing $\mathcal {H}_{\infty }$ dynamic output feedback reliable controller for discrete-time Markov jump nonlinear systems with persistent dwell-time switched transition probabilities based on the Tagaki–Sugeno fuzzy model. The uncertainty of measurement output, which is assumed to occur randomly, and mode-dependent actuator faults are considered simultaneously. Moreover, the jumping property presented by system modes is described by the Markov chain of which transition probabilities are considered to be piecewise time-varying, and is described by adopting the more flexible persistent dwell-time switching rule. Based on the stochastic analysis approach and Lyapunov stability theory, some sufficient conditions are established to ensure the resulting closed-loop system being mean-square exponentially stable with the prescribed $\mathcal {H}_{\infty }$ performance. Furthermore, the desired controller gains can be obtained through solving a convex optimization problem. Finally, the practicability and availability of the proposed control method are illustrated by a numerical example and a modified tunnel diode circuit model.
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