Gap junction communication is an essential component in the mechanosensitive response of tenocytes. However, little is known about direct mechanoregulation of gap junction turnover and permeability. The present study tests the hypothesis that mechanical loading alters gap junction communication between tenocyte within tendon fascicles. Viable tenocytes within rat tail tendon fasicles were labelled with calcein-AM and subjected to a fluorescent loss induced by photobleaching (FLIP) protocol. A designated target cell within a row of tenocytes was continuously photobleached at 100% laser power whilst recording the fluorescent intensity of neighbouring cells. A mathematical compartment model was developed to estimate the intercellular communication between tenocytes based upon the experimental FLIP data. This produced a permeability parameter, k, which quantifies the degree of functioning gap functions between cells as confirmed by the complete inhibition of FLIP by the inhibitor 18α-glycyrrhentic acid. The application of 1N static tensile load for 10 min had no effect on gap junction communication. However, when loading was increased to 1 h, there was a statistically significant reduction in gap junction permeability. This coincided with suppression of connexin 43 protein expression in loaded samples as determined by confocal immunofluorescence. However, there was an upregulation of connexin 43 mRNA. These findings demonstrate that tenocytes remodel their gap junctions in response to alterations in mechanical loading with a complex mechanosensitive mechanism of breakdown and remodelling. This is therefore the first study to show that tenocyte gap junctions are not only important in transmitting mechanically activated signals but that mechanical loading directly regulates gap junction permeability.

Deterministic lateral displacement (DLD) technology is a newly developed method which can separate microscale and nanoscale particles continuously and efficiently. In this paper, a direct numerical simulation method (i.e. a fictitious domain method) is used to simulate the motion of an elastic particle (modelled as homogeneously elastic body) in the DLD device. The effects of the particle deformability on the critical separation diameter are investigated. Our results indicate that there exists a critical deformability, below which the critical diameter decreases with increasing deformability, whereas beyond which the critical diameter increases with increasing deformability. The reasons are discussed via the consideration of the effects of the particle deformation and the lubrication force on the lateral position of the particle centre point. In addition, our results show that the increase in the gap distance between adjacent posts in both directions or in the longitudinal direction alone leads to the increase in the critical particle size with respect to the gap size, which can be explained by the lateral position of the separation streamline of the undisturbed flow.

Compared with the classic flow on macroscale, flows in microchannels have some new phenomena such as the friction increase and the flow rate reduction. Papautsky and co-workers explained these phenomena by using a micropolar fluid model where the effects of micro-rotation of fluid molecules were taken into account. But both the curl of velocity vector and the curl of micro-rotation gyration vector were given incorrectly in the Cartesian coordinates and then the micro-rotation gyration vector had only one component in the z-direction. Besides, the gradient term of the divergence of micro-rotation gyration vector was missed improperly in the angular moment equation. In this paper, the governing equations for laminar flows of micropolar fluid in rectangular microchannels are reconstructed. The numerical results of velocity profiles and micro-rotation gyrations are obtained by a procedure based on the Chebyshev collocation method. The micropolar effects on velocity and micro-rotation gyration are discussed in detail.

A solar-powered unmanned seaplane is proposed as a new strategy to avoid the challenges faced in a long nonstop solar-powered flight, and is especially designed for sea surveillance mission, like resource exploration, environmental monitoring, and observation of animal migration. A preliminary design of the solar-powered unmanned seaplane is carried out while its flight performance is analyzed later. The conceptual design of a twin-tail boom with large aspect ratio wings and buoyancy system is put forward. Aerodynamic loading of the wings is analyzed and determined by computational fluid dynamics. The energy balance models of the proposed seaplane system are created for the periods that the seaplane moors on the sea to harvest solar energy and flies in the sky to perform the mission. The parameter effects, such as wing loading, takeoff time, weight, cruise speed, takeoff ground distance, takeoff ground time, flight envelope, and endurance are discussed. The energy balance models shows that the proposed solar-powered seaplane can perform the sea surveillance mission at an altitude of around 8 km for months and seasons between latitude 60 ° N and 60 ° S.

A fast multiobjective optimization method for S-duct scoop inlets considering both inflow and outflow is developed and validated. To reduce computation consumption of optimization, a simplified efficient model is proposed, in which only inflow region is simulated. Inlet pressure boundary condition of the efficient model is specified by solving an integral model with both inflow and outflow. An automated optimization system integrating the computational fluid dynamics analysis, nonuniform rational B-spline geometric representation technique, and nondominated sorting genetic algorithm II is developed to minimize the total pressure loss and distortion at the exit of diffuser. Flow field is numerically simulated by solving the Reynolds-averaged Navier–Stokes equation coupled with k–ω shear stress transport turbulence model, and results are validated to agree well with previous experiment. S-duct centreline shape and cross-sectional area distribution are parameterized as the design variables. By analyzing the results of a suggested optimal inlet chosen from the obtained Pareto front, total pressure recovery has increased from 97% to 97.4%, and total pressure distortion DC60 has decreased by 0.0477 (21.7% of the origin) at designed Mach number 0.7. The simplified efficient model has been validated to be reliable, and by which the time cost for the optimization project has been reduced by 70%.

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Dynamic voltage restorer (DVR) based on transformer-coupled topology is the most cost-effective solution to protect consumer from voltage sags. However, an important issue about this topology is the transformer saturation. Magnetic saturation of the transformer will generate large inrush current which may greatly distort the compensation voltage or even trigger the over-current protection. To prevent the transformer from saturation, this study proposes a novel direct magnetising flux linkage control strategy. Distinguished from existing DVR models which ignored the transformer magnetising branch, this study establishes a comprehensive DVR model by adopting the magnetising flux linkage as a state-variable. Therefore, by adopting flux linkage feedback, the magnetising flux linkage would be directly controlled. Otherwise, to implement the flux linkage control, this study proposes a robust flux estimation method to carry out the proposed control scheme. Finally, the whole system is verified on a 380 V/10 kVA three-phase experimental DVR prototype.

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