•TPIMS was proposed as a lightweight device to reduce wind turbine tower vibrations.•An optimum design method was developed to minimize tuned mass weight of TPIMS.•TPIMS shows robustness and is ...superior to TMD in the aspect of additional mass.
Traditional tuned mass dampers have been studied to reduce vibration responses of wind turbine towers. However, the large additional mass is usually required to be installed at the top of the tower, which may be not suitable for existing wind turbine tower. To provide a retrofit technology for in-service wind turbines, the use of a lightweight energy dissipation device, the tuned parallel inerter mass system (TPIMS), for seismic response mitigation of the wind turbine tower, was proposed in this study. The TPIMS consists of a tuned mass, a spring, and a parallel inerter subsystem, of which the spring is used for tuning the mass and the inerter subsystem is set for vibration energy absorbing and dissipation. A TPIMS-design optimization method was developed for wind turbine tower vibration depression with a target performance level. A typical wind turbine tower was modeled according to the Bernoulli-Euler beam theory and its seismic responses subject to stochastic seismic excitations were obtained. Parametric studies were conducted and the robustness of TPIMS for tower seismic vibration mitigation was proved. The results show that the tower top displacement, base shear, and moment can be reduced significantly with the help of TPIMS. Under a same design target, the required physical mass of TPIMS is much smaller than that of the tuned mass damper. Additionally, a lager apparent mass of TPIMS is more effective for reducing seismic responses of the wind turbine tower.
•Negative stiffness amplification system-strengthened isolation system (NSAS-IS)•NSAS-IS for multiperformance upgrading of containment structures.•Design principle of NSAS-IS for enhanced energy ...dissipation efficiency.•NSAS-IS for improved isolating effects under multiple intensity excitations.•Structural energy dissipation burden significantly relieved by NSAS-IS.
As an efficient and crucial energy-generation facility, a nuclear power plant requires a high level of seismic safety as its failure can lead to catastrophic events. In this study, a novel negative-stiffness amplification system-strengthened isolation system (NSAS-IS) is constructed for seismic performance upgrading of containment structures. Moreover, a multiperformance-oriented design principle is developed for the NSAS-IS to enable enhanced energy dissipation and robust control during multi-intensity seismic excitations. The NSAS-IS comprises an NSAS and parallelly arranged isolators; in particular, the NSAS comprises a tuning spring in series with a sub-configuration including a negative-stiffness device and dashpot in parallel. Herein, the mechanical models and physical realization of the NSAS and isolators are established, based on which the equivalent negative-stiffness effect and enhanced energy dissipation capacity are elucidated. A mechanical model of an NSAS-IS-equipped containment structure, as the last safety defense of the inner structure of a nuclear power plant, and its governing equation and finite element model are established. A design principle, aimed at multiperformance upgrading, is developed for the NSAS-IS. Considering the typical containment structure as an example, the advantages of the proposed NSAS-IS and design principle are investigated for multiple seismic performances, including the deformation and shear force responses of the isolation layer as well as the deformation and acceleration responses of the containment shell. The results obtained indicate that installing the NSAS-IS at the bottom of the containment structure provides improved isolation owing to the equivalent negative-stiffness effect; consequently, the multiple responses of the superstructure and isolation layer are reduced more significantly than with conventional isolators. Benefiting from the multiperformance-oriented design and deployed NSAS, the new isolation system exhibits an enhanced energy dissipation efficiency and capacity, simultaneously maintaining the isolation phenomenon. Thus, the total energy dissipation burden on the primary structures can be relieved by the NSAS, which robustly dissipates intense vibrational energies during multi-intensity excitations.
Summary
Interactions among an inerter, spring, and energy dissipation element (EDE) in an inerter system can result in a higher energy dissipation efficiency compared to a single identical EDE, which ...is referred to as the damping enhancement effect. Previous studies have mainly concentrated on the vibration mitigation effect of the inerter system without an explicit consideration or utilization of the damping enhancement mechanism. In this study, the theoretical essence of the damping enhancement effect is discovered, and a universal design principle is proposed for an inerter system. A fundamental equation is found and demonstrated on the basis of closed‐form stochastic responses, which establishes a bridge between the damping deformation enhancement factor (DDEF) and the response mitigation ratio, thus clarifying the relationship of the damping enhancement effect and the response mitigation effect. Inspired by the equation, a novel damping‐enhancement‐based strategy is proposed to determine the key parameters of an inerter system. Following the performance‐demand‐based design philosophy, the parameters of the inerter system can be determined in the design condition of a target‐damping‐enhancement effect. Through the implementation of the damping enhancement equation, the damping parameter of an inerter system can be directly obtained by the prespecified DDEF and the displacement response mitigation ratio. The influence of parameters on the response mitigation effect and the damping enhancement effect is then investigated to determine ways of obtaining the other two parameters in an inerter system. Finally, design examples are conducted to verify the proposed strategy and the theoretical relationship revealed by the damping enhancement equation. The results show that the proposed design strategy explicitly utilizes the damping enhancement effect for vibration control, where the target of the DDEF is effective in enhancing the efficiency of the EDE for energy dissipation. In the design condition of the target DDEF, the implementation of the proposed damping enhancement equation provides an inerter system with a practical equation to determine the key parameters of an inerter system in a direct manner.
Current programmed death‐1 ligand (PD‐L1)‐based therapy focuses on local tumors. However, circulating exosomal PD‐L1 possesses inherent anti‐PD‐L1 blockade resistance and dominates tumor metastasis, ...playing a critical role in systemic immunosuppression. Therefore, the efficacy of immune checkpoint therapy depends on simultaneously decreasing tumoral and circulating exosomal PD‐L1. However, such therapeutic platforms have never been reported so far. Herein, a PD‐L1 checkpoint‐regulatable immune niche created by an injectable hydrogel is reported to reprogram PD‐L1 of both tumor and circulating exosomes. Oxidized sodium alginate‐armored tumor membrane vesicle (O‐TMV) as a gelator, with Ca2+ channel inhibitor dimethyl amiloride (DMA) and cyclin‐dependent kinase 5 (Cdk5) inhibitor roscovitine formed hydrogel (O‐TMV@DR) in vivo, work as an antigen depot to create an immune niche. O‐TMV chelates Ca2+ within the tumor environment and DMA continuously prevents cellular Ca2+ influx, suppressing Ca2+‐governed exosome secretion with decreased exosome number. Roscovitine not only down‐regulates tumor cell PD‐L1 expression along with decreasing exosomal PD‐L1 expression inherited from parental tumor cells via a genetic blockade effect, but also blunts the cascade connection between PD‐L1 up‐regulation and interferon‐γ stimulation, achieving down‐regulated PD‐L1 expression in both tumor cells and exosomes. Therefore, a full‐scale reprogramming of both tumoral PD‐L1 and exosomal PD‐L1 is achieved, offering an innovative immune checkpoint‐regulatable cancer immunotherapy
A checkpoint‐regulatable immune niche created by a newly designed tumor membrane vesicle‐based injectable hydrogel demonstrates potent ability for simultaneously reprogramming tumoral programmed death‐1 ligand (PD‐L1) and exosomal PD‐L1, enabling powerful inhibition of tumor metastasis as well as inducing strong immunological memory via disrupting PD‐L1‐based immunosuppression. This study opens up a conceptually innovative avenue for PD‐L1‐based immune checkpoint therapy.
•A Pole-inspired optimization methodology for TVMDs dealing with impulse loads.•Analytical design formula for TVMD structure with the highest convergence speed.•Optimized TVMD-structure with a timely ...response to impulses and a low peak response.•Maximum response spectra for the preliminary design of inerter within the TVMD.
The inerter-based damper has proven as an efficient vibration suppression device for steady responses in a broad frequency band. However, the inerter-based structures may experience an impulsive loading process, in which the dynamic performance and pertinent design method remain unknown. Dealing with this, this study proposes a time-decay rate-based optimal design methodology for a typical inerter-based damper, tuned viscous mass damper (TVMD), to suppress the impulse-induced vibration, successively deriving the analytical formula to facilitate the demand-oriented design. Considering the impulsive circumstance, the mechanical model of the TVMD-based structure is established, and a pole-based analysis is performed to quantify the functionality of TVMDs for the transient response attenuation. Inspired by the pole-based analysis result, a time-decay rate-based optimal design method and corresponding analytical formula are proposed to maximize the attenuation rate of TVMDs. Through the implementation of TVMD-based structures, the effectiveness of the pole-based design method is demonstrated by the dimensionless analysis, and then its advantages are illustrated through a comparison with the previous design method. Furthermore, a series of maximum response spectra are established to quantify the dynamic performances of TVMDs. The results show that the pole-inspired design method guarantees the TVMD improved transient attenuation rate and degrees, in comparison with the widely used fixed-point method. In addition, the provided transient response spectra can be adopted as a guideline or reference for the performance evaluation of the TVMD-equipped structure and the preliminary design of TVMDs to meet the expected vibration suppression demand for impulsive excitations.
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Droplet manipulations are fundamental to numerous applications, such as water collection, medical diagnostics, and drug delivery. Structure-based liquid operations have been widely used both in ...nature and in artificial materials. However, current strategies depend mainly on fixed structures to realize unidirectional water movement, while multiple manipulation of droplets is still challenging. Here, we propose a magnetic-actuated robot with adjustable structures to achieve programmable multiple manipulations of droplets. The adjustable structure redistributes the resisting forces from the front and rear ends of the droplets, which determine the droplet behaviors. We can transport, split, release, and rotate the droplets using the robot. This robot is universally applicable for manipulation of various fluids in rough environments. These findings offer an efficient strategy for automated manipulation of droplets.
Highlights
Core–shell structured SnS
2
@C hollow nanospheres were synthesized.
The uniform carbon coating and hollow structure can alleviate the mechanical strain and therefore electrochemical ...performance.
Constructing unique and highly stable structures with plenty of electroactive sites in sodium storage materials is a key factor for achieving improved electrochemical properties through favorable sodium ion diffusion kinetics. An SnS
2
@carbon hollow nanospheres (SnS
2
@C) has been designed and fabricated via a facile solvothermal route, followed by an annealing treatment. The SnS
2
@C hybrid possesses an ideal hollow structure, rich active sites, a large electrode/electrolyte interface, a shortened ion transport pathway, and, importantly, a buffer space for volume change, generated from the repeated insertion/extraction of sodium ions. These merits lead to the significant reinforcement of structural integrity during electrochemical reactions and the improvement in sodium storage properties, with a high specific reversible capacity of 626.8 mAh g
−1
after 200 cycles at a current density of 0.2 A g
−1
and superior high-rate performance (304.4 mAh g
−1
at 5 A g
−1
).
•Isolated tuned liquid dampers (ITLDs) for dual-mode vibration control.•Design methodology of a pair of ITLDs for dual-mode control of MDOF structures.•ITLD-based robust mitigation of seismic ...responses for MDOF structures.•Improved multi-response reduction superior to TLDs with the same parameters.•Accelerations of different floors suppressed by the isolating ability of ITLDs.
The tuned liquid damper (TLD) has been proven as an effective vibration mitigation device. However, it is less efficient and robust under seismic excitations. Addressing this issue, this study proposes a dual-mode-based design methodology utilizing a pair of isolated TLDs (ITLDs) for the multi-performance vibration mitigation of multi-degree-of-freedom (MDOF) structures. Oriented by the dual-mode control target, a series of 2DOF structures were considered, and a mechanical model of the considered ITLD was established. The modal analysis was performed for the primary structure, on the basis of which feasible installation methods for the ITLDs are proposed. Correspondingly, an extensive parametric analysis and a frequency response analysis were conducted, which revealed the control advantages of a pair of ITLDs, and we explored the potential optimal design for the liquid mass and added isolation layer. Inspired by the parametric analysis results, a mode-based design procedure is proposed for a pair of ITLDs by incorporating the modal characteristics of the primary structure. Finally, the ITLDs were applied in a multi-story building structure to illustrate the effectiveness of the devices and proposed design method. The obtained analysis results show that the dual-mode mitigation effect can be satisfactorily achieved using a pair of ITLDs with the proposed design approach, as well as synthetic functionality of the pair of ITLDs. The employment of a pair of ITLDs provided effective and robust mitigation of seismic responses for MDOF structures, yielding an improved multi-response reduction compared with the TLDs with the same parameters. In particular, the seismic-excited structural acceleration responses can be suppressed for different floors, which cannot be achieved by conventional TLDs.
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Perovskite solar cells (PSCs) are promising candidates for power sources to sustainably drive next-generation wearable electronics, following the advances in PSCs and future desires of harvesting and ...storing energy integration. However, the natural brittle property of crystals for elastic deformation restricts the mechanical robustness, which definitely results in degraded efficiency. In fact, the crystalline quality and “cask effect” impact large-area reproducibility of PSCs. Inspired by the highly crystalline and tough nacre, herein, we report biomimetic crystallization to grow high-quality perovskite films with an elastic “brick-and-mortar” structure. The antithetic solubility of the composite matrix facilitates perpendicular micro-parallel crystallization and affords stretchability to resolve the “cask effect” of flexible PSCs. We successfully fabricate PSC chips (1 cm 2 area) with average efficiencies of 19.59% and 15.01% on glass and stretchable substrates, respectively. Importantly, a recorded 56.02 cm 2 area wearable solar-power source with 7.91% certified conversion efficiency is achieved. This skin fitting power source shows bendability, stretchability and twistability and is practically assembled in wearable electronics.
•Multi-negative stiffness amplification systems (NSAS) with improved damping effect.•Multi-location NSAS approach developed for complex underground structures.•Dual isolation of a column with a pair ...of NSASs for multi-intensity excitations.•Structural plastic energy dissipation burden significantly relieved by NSAS.•Residual deformation of columns avoided by the isolating ability of NSASs.
Underground structures are vulnerable to strong earthquakes, with their central columns being prone to damage owing to their insufficient resistance capacity. In this study, an effective, hybrid, and multi-location seismic isolation approach was proposed for multi-floor and multi-span underground structures using several negative-stiffness amplification system-based isolation systems (NSAS-ISs). The NSAS-IS originated from the incorporation of an NSAS and an isolation bearing, which was proposed as a flexible connection installed at either the top or bottom of the central columns. The mechanical model as well as physical realization of the NSAS-IS was explored, and an improved damping mechanism was introduced. Subsequently, a multi-location isolation method was proposed with the NSAS-ISs installed at the top or bottom of the columns (corresponding to the 1-end-based isolation method) and at both the top and bottom of the columns (corresponding to the 2-end-based isolation method). The effectiveness and robustness of the proposed NSAS-IS pertaining to the structural seismic response mitigation of typical underground structures under different isolation methods were investigated, focusing on the underground structures buried at different depths subject to various seismic excitations at multiple intensities. The obtained results indicated the effectiveness of both the 1-end- and 2-end-based isolation methods for NSAS-IS in improving the seismic performance of multi-floor and multi-span underground structures, with significant improvement being observed in the damping and isolation effects. In particular, the 2-end isolation method was found to be considerably effective in multi-performance control for multi-intensity excitations and is thus suggested for underground structures with limited space for installation and isolation layers. Consequently, the plastic energy-dissipation burden of the primary structures can be significantly relieved, and the residual deformation of the columns can be avoided owing to their excellent isolation ability.
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