Wireless sensor network (WSN) is an interestingly promising technology with many applications in intelligent environment-monitoring. Its energy consumption is, however, essentially challenged after ...it is deployed. In this paper, we developed a low-resonant-frequency piezoelectric energy harvesting device as an alternative to power WSN deployed in a weak vibration environment. An energy management module, equipped with a full-bridge rectifier (FBR), a fully self-powered voltage controller, and a logic-level protection circuit was designed to enable a regulated voltage to intermittently drive WSN for temperature monitoring. The power transfer efficiency of FBR reached 42%, presenting a good performance/cost ratio in the case of a relatively high open-circuit voltage of 8 V and a low rectified voltage of 3.3 V. The experimental results have demonstrated that the proposed WSN was successfully driven at an interval time of less than 1 min, and fully self-powered by the scavenged energy from the environmental vibration source of a 0.15-g acceleration and a 40-Hz vibration frequency.
To meet the requirements for motion estimation of a swarm of micro-aerial vehicles in a GPS-restricted environment, a distributed motion estimation algorithm is proposed that combines an inertial ...measurement unit, magnetometer, wireless ranging network and altimeter data. Based on the information sharing and mutual positioning ability of the wireless sensor network, the long-term stability of motion estimation in a GPS-restricted environment is improved on the basis of information from neighboring vehicles. A centralized information filter for large-scale swarm micro-aerial vehicles is proposed that uses the information distribution principle. To address the difficulty of high-dimensional state inversion in centralized information filtering, the theory of distributed information filters for large-scale systems is adopted to decompose the high-dimensional optimal centralized information filter into distributed sub-filters. Based on the logged data, the simulation results show that the accuracy of motion estimation using the distributed filtering method is not significantly lower than with centralized filtering, and is more suitable for distributed deployment on micro-aerial vehicles, enabling stable motion estimation to be maintained in a GPS-restricted environment.
The concentration distribution of combustible dust determines thermal intensity distribution during an explosion. Current measurements for dust concentration have their particular limitations. ...Targeting this, we proposed an “ultrasonic-electric” hybrid detection system and a fusion model. We deployed 12 of the ultrasonic-electric hybrid systems in orthogonal arrays to comprehensively observe the clouds. First, the ultrasonic-electric hybrid detection systems obtained concentration data in real time, and those data were calculated by fusion model. Then, the clouds and their concentrations changing with time were depicted. We analyzed those trends and found certain patterns in them. Our approach can provide a fast, accurate way to detect concentrations of dynamic and complex dust. Finally, the corresponding relationship between the dust concentration distribution and its explosive heat intensity distribution is obtained. The results show that the thermal distribution of combustible dust at a concentration of 20-120 g/m
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is proportional to the concentration. This is important for preventing dust explosions and reducing the thermal intensity of explosions.
Being independent of any fixed equipment, Ad Hoc wireless sensor networks, a kind of acentric and self-organized wireless network, possesses some features such as easiness of deployment, strong ...invulnerability and flexibility of networking, which leads to a promising application prospect in terms of UAV military and civilian use. This paper proposes a new slot adaptive 4D network clustering algorithm based on UAV autonomous formation and reconfiguration to solve the problem of UAV Ad Hoc network such as networking confusion, poor network reconstruction performance, huge energy consumption and other issues. The algorithm can optimize the topology of UAVs network. We build the network topology and generate clustering network by the slot adaptive 4D network clustering algorithm in Matlab. According to the real combat of UAV, four states are simulated and analyzed. The simulation results validate the feasibility of the slot adaptive 4D network clustering algorithm. The clustering structure generated by the slot adaptive 4D network clustering algorithm is robust and the algorithm is suitable for the UAV group operation.
Detonation waves released by energetic materials provide an important means of physical self-destruction (Psd) for information storage chips (ISCs) in the information insurance field and offer ...advantages that include a rapid response and low driving energy. The high electrical sensitivity of energetic materials means that they are easily triggered by leakage currents and electrostatic forces. Therefore, a Psd module based on a graphene-based insurance actuator heterogeneously integrated with energetic materials is proposed. First, the force–balance relation between the electrostatic van der Waals force and the elastic recovery force of the insurance actuator’s graphene electrode is established to realize physical isolation and an electrical interconnection between the energetic materials and the peripheral electrical systems. Second, a numerical analysis of the detonation wave stress of the energetic materials in the air domain is performed, and the copper azide dosage required to achieve reliable ISC Psd is obtained. Third, the insurance actuator is prepared via graphene thin film processing and copper azide is prepared via an in situ reaction. The experimental results show that the energetic materials proposed can release physical isolation within 14 μs and can achieve ISC Psd under the application of a voltage signal (4.4–4.65 V). Copper azide (0.45–0.52 mg) can achieve physical damage over an ISC area (23.37–35.84 mm2) within an assembly gap (0.05–0.25 mm) between copper azide and ISC. The proposed method has high applicability for information insurance.
Drones equipped with visible and infrared sensors play a vital role in urban road supervision. However, conventional methods using RGB-IR image pairs often struggle to extract effective features. ...These methods treat these spectra independently, missing the potential benefits of their interaction and complementary information. To address these challenges, we designed the Multispectral Feature Mutual Guidance Network (MFMG-Net). To prevent learning bias between spectra, we have developed a Data Augmentation (DA) technique based on the mask strategy. The MFMG module is embedded between two backbone networks, promoting the exchange of feature information between spectra to enhance extraction. We also designed a Dual-Branch Feature Fusion (DBFF) module based on attention mechanisms, enabling deep feature fusion by emphasizing correlations between the two spectra in both the feature channel and space dimensions. Finally, the fused features feed into the neck network and detection head, yielding ultimate inference results. Our experiments, conducted on the Aerial Imagery (VEDAI) dataset and two other public datasets (M3FD and LLVIP), showcase the superior performance of our method and the effectiveness of MFMG in enhancing multispectral feature extraction for drone ground detection.
Traditional silicon-based micro-electro-mechanical system (MEMS) safety and arming devices, such as electro-thermal and electrostatically driven MEMS safety and arming devices, experience problems of ...high insecurity and require high voltage drive. For the current electromagnetic drive mode, the electromagnetic drive device is too large to be integrated. In order to address this problem, we present a new micro electromagnetically driven MEMS safety and arming device, in which the electromagnetic coil is small in size, with a large electromagnetic force. We firstly designed and calculated the geometric structure of the electromagnetic coil, and analyzed the model using COMSOL multiphysics field simulation software. The resulting error between the theoretical calculation and the simulation of the mechanical and electrical properties of the electromagnetic coil was less than 2% under the same size. We then carried out a parametric simulation of the electromagnetic coil, and combined it with the actual processing capacity to obtain the optimized structure of the electromagnetic coil. Finally, the electromagnetic coil was processed by deep silicon etching and the MEMS casting process. The actual electromagnetic force of the electromagnetic coil was measured on a micro-mechanical test system, compared with the simulation, and the comparison results were analyzed.
With the development of micro technology, the fuse for small-caliber projectiles tends to be miniaturized and intelligent, the traditional fuse no longer meets the requirements. In this paper, we ...demonstrate a micro safety and arming (S & A) device with small volume and high reliability in small caliber projectile platforms. The working principle of S & A devices is that a centrifugal insurance mechanism could deform under a centrifugal load and thus cause fuse safety arming. The centrifugal insurance mechanism is designed theoretically, verified by simulation and experimental methods. The experimental results show that, when the rotary speed is over 36,000 rpm, the fuse was armed safely. In addition, the experimental, simulation, and theoretical results are basically consistent, and indicate that the centrifugal insurance mechanism meets the expected criteria.
Abstract
Implantable drug-delivery microsystems have the capacity to locally meet therapeutic requirements by maximizing local drug efficacy and minimizing potential side effects. The internal organs ...of the human body including the esophagus, gastrointestinal tract, and respiratory tract, with anfractuos contours, all manifest with endoluminal lesions often located in a curved or zigzag area. The ability of localized drug delivery for these organs using existing therapeutic modalities is limited. Spraying a drug onto these areas and using the adhesion and water absorption properties of the drug powder to attach to lesion areas can provide effective treatment. This study aimed to report the development and application of microsystems based on microshockwave delivery of drugs. The devices comprised a warhead-like shell with a powder placed at the head of the device and a flexible rod that could be inserted at the tail. These devices had the capacity to deposit drugs on mucous membranes in curved or zigzag areas of organs in the body. The explosive impact characteristics of the device during drug delivery were analyzed by numerical simulation. In the experiment of drug delivery in pig intestines, we described the biosafety and drug delivery capacity of the system. We anticipate that such microsystems could be applied to a range of endoluminal diseases in curved or zigzag regions of the human body while maximizing the on-target effects of drugs.
A low-driving energy and bistable recoverable MEMS safety and arming device (S&A), based on microcasting technology and deep silicon etching technology, is proposed to meet safety system ...requirements. A force-electromagnetic combination solution is constructed for the Si MEMS S&A, with parameters and strength verified, ultimately achieving an S&A size of (13 × 13 × 0.4) mm. Additionally, a low-driving energy U-shaped electromagnetic coil (USEC) model is designed using microcasting technology, and an electrical-magnetic-mechanical coupling mathematical model is established to explore the relationship between design parameters and driving capacity and reliability. With a driving power of 8 V/0.5 A, the model achieves a stable electromagnetic driving force of 15 mN with a travel distance of 0.5 mm. Finally, the fabrication and testing of the USEC and S&A are carried out, with driving capability and S&A disarming ability tests conducted to verify the feasibility of the system design. Compared to the existing S&A, this scheme has the advantages of low-driving energy, recoverability, fast response speed, and strong adaptability.
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