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Impact detecting and counting are fundamental functions of fuses used in hard target penetration weapons. However, detection failure caused by battery breakdown in high-g acceleration environments poses a vulnerability for such weapons. This paper introduces a novel supercapacitor that combines energy storage and high-g impact detection, called self-sensing supercapacitor. By deliberately inducing a transient soft short-circuit during shock in the supercapacitor, it is possible to detect external impact by its transient voltage drop. To realize this concept, firstly, by introducing the contact theory and force-induced percolation model, the electrode strength and roughness are found to have key impacts on the formation of soft circuits. Subsequently, to meet the needs for sensitivity and capacity, a high-density porous carbon (HDPC) that combines high mechanical strength and porosity, is selected as a suitable candidate based on the analysis results. Furthermore, a two-step curing method is proposed to prepare the high-roughness HDPC (HRHDPC) electrode and to assemble the self-sensing supercapacitor. Due to the rich specific surface of the electrodes and the high surface strength and roughness conducive to the formation of transient soft short circuits, the self-sensing supercapacitor not only possesses an excellent specific capacitance (171 F/g at 0.5 A/g) but also generates significant voltage response signals when subjected to high-g impacts ranging from 8000g to 31,000g. Finally, the self-sensing supercapacitor is applied to compose a successive high-g impact counting system and compared to traditional solutions (sensors and tantalum capacitors) in the military fuzes. The results show that the self-sensing supercapacitor-based system exhibits advantages in terms of size, power consumption, and counting accuracy. [ABSTRACT FROM AUTHOR]

The dynamic management of sensor nodes and advanced information fusion are necessary technologies to enhance the comprehensive performance of sensor networks. This paper presents a cascaded sensor dynamic activation and information fusion algorithm to simultaneously optimize the energy and sensing performance of wireless sensing networks. The proposed algorithm dynamically activates nodes that are most suitable for the current sensing task through a joint event-driven and state ranking activation algorithm that achieves a better sensing performance with lower energy costs. In addition, it further utilizes the sensing information of all the activated nodes with maximum efficiency, through an improved distributed Kalman information fusion, which achieves an extra improvement in sensing accuracy as measured by the minimum variance. Finally, the superiority of the proposed cascaded algorithm is verified by a simulation comparison, achieving almost zero dead nodes in terms of energy, and a 62.1% decrease in average error in terms of sensing. [ABSTRACT FROM AUTHOR]

On June 17, 2020, Aniangzhai landslide, an ancient landslide located in Danba County, southwest China, was reactivated by Meilonggou debris flow. The front edge of the slope collapsed, mobilizing a soil mass of about 2.35 × 106 m3. Evaluating the stability of the whole slope is of great importance to avoid further landslides and mitigate the damage for Aniangzhai villagers living on this slope. This paper focuses on the inaccessible upper slope of Aniangzhai landslide (no attention paid before) that exhibits a relative elevation difference of more than 1000 m. Multi-source remote sensing, including unmanned aerial vehicle (UAV) photogrammetry, light detection and ranging (LiDAR), and satellite-based interferometric synthetic aperture radar (InSAR) techniques, was used in this research to identify and evaluate this high mountain upper slope potential hazard in Aniangzhai landslide. Considering the huge height difference and the steep slope of Aniangzhai landslide, an iterative route planning method was proposed and adopted to obtain a 3D model with 0.02 m resolution and a DEM with 0.25 m resolution by using UAV and LiDAR close-in flight method, respectively. Meter-level huge cracks were clearly identified by the high-resolution UAV 3D model and LiDAR data, which confirm that the location of these cracks is related to the morphological structure of this ancient landslide. Time series InSAR analysis reveals the activity of this high-altitude area, with a maximum LOS displacement rate of 15 cm/a. The combination of the above remote sensing technologies confirms and reveals the high potential risk and the reactivated condition of the upper slope of Aniangzhai landslide. Through this finding, we show that the evolution of Aniangzhai landslide happened through four stages with a cascading effect. This paper proves the usefulness of an integrated method to successfully identify and evaluate the high-altitude upper slope potential hazard and compares the technical features of them, providing a reference for future works that aimed at mitigating the potential damage of the upper slope. [ABSTRACT FROM AUTHOR]

Supercapacitors (SCs) have been successfully used in electric vehicles or military equipment systems for their high power density. However, the mechanical impacts from vehicle crashes and missile penetration probably cause performance fluctuations or failure of SCs, which may threaten the safety of systems using SCs. In this paper, a generalized circuit model to analyze the transient process of SCs under mechanical loads is proposed. The circuit model simultaneously takes capacitance change, internal short-circuit and resistance change into account, and an extra resistor-capacitor circuit (RCC) is added to simulate the nonlinear behavior during charging and discharging. Subsequently, the relationships between pressure and fundamental circuit parameters are determined by static methods. By taking the static test data into the circuit model, the transient response of different types of SCs under particular mechanical loading conditions is predicted. Finally, the influences of some crucial parameters on the voltage responses of SCs are revealed based on the simulations, which provide references for designing and optimizing mechanical load-resistant or self-sensing SCs in specific application scenarios. [ABSTRACT FROM AUTHOR]

As an elegant nonparametric Bayesian method, Gaussian process regression (GPR) has been successfully applied to image denoising. However, the traditional GPR faces the problem of intensive computational complexity and difficulty in capturing local-structure information. In this paper, a novel neighborhood-based image denoising method motivated by the GPR is proposed. An image is divided into several patches, and each pixel in the patches is predicted by its neighborhoods through the GPR, which allows the priors to be local and relevant and reduces the complexity of the GPR. Besides, a composite covariance function is designed to capture the local similarity between pixels. The extensive experiments demonstrate that the proposed method can not only produce a favorable denoising performance, but also have a relatively low time consumption. [ABSTRACT FROM AUTHOR]

Timely and effective post-disaster assessment is of significance for the design of rescue plan, taking disaster mitigation measures and disaster analysis. Field investigation and remote sensing methods are the common ways to perform post-disaster assessment, which are usually limited by dense cloud coverage, potential risk, and tough transportation etc. in the mountainous area. In this paper, we employ the 2017 catastrophic Xinmo landslide (Sichuan, China) to demonstrate the feasibility of using spaceborne synthetic aperture radar (SAR) data to perform timely and effective post-disaster assessment. With C-band Sentinel-1 data, we propose to combine interferometric coherence to recognize the stable area, which helps us successfully identify landslide source area and boundaries in a space-based remote sensing way. Complementarily, X-band TanDEM-X SAR data allow us to generate a precise pre-failure high-resolution digital elevation model (DEM), which provides us the ability to accurately estimate the depletion volume and accumulation volume of Xinmo landslide. The results prove that spaceborne SAR can provide a quick, valuable, and unique assistance for post-disaster assessment of landslides from a space remote sensing way. At some conditions (bad weather, clouds, etc.), it can provide reliable alternative. [ABSTRACT FROM AUTHOR]

In this study, the discharge voltage behavior of electric double-layer capacitors (EDLCs) during high- g impact is studied both theoretically and experimentally. A micro-scale dynamic mechanism is proposed to describe the physical basis of the increase in the discharge voltage during a high- g impact. Based on this dynamic mechanism, a multi-field model is established, and the simulation and experimental studies of the discharge voltage increase phenomenon are conducted. From the simulation and experimental data, the relationship between the increased voltage and the high- g acceleration is revealed. An acceleration detection range of up to 10,000 g is verified. The design of the device is optimized by studying the influences of the parameters, such as the electrode thickness and discharge current, on the outputs. This work opens up new avenues for the development of autonomous sensor systems based on energy storage devices and is significant for many practical applications such as in collision testing and automobile safety. [ABSTRACT FROM AUTHOR]

At 5:38 am on the 24th June, 2017, a catastrophic rock avalanche destroyed the whole village of Xinmo, in Maoxian County, Sichuan Province, China. About 4.3 million m of rock detached from the crest of the mountain, gained momentum along a steep hillslope, entrained a large amount of pre-existing deposits, and hit the village at a velocity of 250 km/h. The impact produced a seismic shaking of ML = 2.3 magnitude. The sliding mass dammed the Songping gully with an accumulation body of 13 million m. The avalanche buried 64 houses; 10 people were killed and 73 were reported missing. The event raised great concerns both in China and worldwide. Extensive field investigation, satellite remote sensing, UAV aerial photography, and seismic analysis allowed to identify the main kinematic features, the dynamic process, and the triggering mechanism of the event. With the aid of ground-based synthetic aperture radar monitoring, the hazard deriving from potential further instabilities in the source area has been assessed. The preliminary results suggest that the landslide was triggered by the failure of a rock mass, which had been already weakened by the M 7.5 Diexi earthquake in 1933. Several major earthquakes since then, and the long-term effect of gravity and rainfall, contributed to the mass failure. The high elevation, slope angle, and vegetation cover in the source area hinder geological field investigation and make hazard assessment difficult. Nonetheless, monitoring and prevention of similar collapses in mountainous areas must be carried out to protect human lives and infrastructures. To this aim, the integrated use of modern high-precision observation technologies is strongly encouraged. [ABSTRACT FROM AUTHOR]

Parasitic capacitance is an unavoidable and usually unwanted capacitance that exists in electric circuits, and it is the most important second-order non-ideal effect that must be considered while designing a triboelectric nanogenerator (TENG) because its magnitude is comparable to the magnitude of the TENG capacitance. This paper investigates the structure and performance optimization of TENGs through modeling and simulation, taking the parasitic capacitance into account. Parasitic capacitance is generally found to cause severe performance degradation in TENGs, and its effects on the optimum matching resistance, maximum output power, and structural figures-of-merit (FOMs) of TENGs are thoroughly investigated and discussed. Optimum values of important structural parameters such as the gap and electrode length are determined for the different working modes of TENGs, systematically demonstrating how these optimum structural parameters change as functions of the parasitic capacitance. Additionally, it is demonstrated that the parasitic capacitance can improve the height tolerance of the metal freestanding-mode TENGs. This work provides a theoretical foundation for the structure and performance optimization of TENGs for practical applications and promotes the development of mechanical energy-harvesting techniques. [ABSTRACT FROM AUTHOR]

Supercapacitors (SCs) are a type of energy storage device with high power density and long lifecycles. They have widespread applications, such as powering electric vehicles and micro scale devices. Working stability is one of the most important properties of SCs, and it is of significant importance to investigate the operational characteristics of SCs working under extreme conditions, particularly during high-g acceleration. In this paper, the failure mechanism of SCs upon high-g impact is thoroughly studied. Through an analysis of the intrinsic reaction mechanism during the high-g impact, a multi-faceted physics model is established. Additionally, a multi-field coupled kinetics simulation of the SC failure during a high-g impact is presented. Experimental tests are conducted that confirm the validity of the proposed model. The key factors of failure, such as discharge currents and discharging levels, are analyzed and discussed. Finally, a possible design is proposed to avoid the failure of SCs upon high-g impact. [ABSTRACT FROM AUTHOR]