This paper describes the dynamic modeling, structural analysis, implementation and experimental test of a Manta-type Unmanned Underwater Vehicle (MUUV). Various controllers such as PID, Sliding mode, and Fuzzy and H ∞ controllers are designed for depth and heading control in order to compare the performance of each controller based on simulation. In addition, experimental tests are carried out in a towing tank for depth keeping and heading angle tracking.
The aging process in transformer insulating oil was studied by measuring the leakage current in a ceramic sensor. The current of the sensor shows a close relationship with the acid value and the breakdown voltage of the transformer oil. The sensor has excellent physico-chemical properties, such as lack of chemical reaction with the oil and stable adsorption of conductive impurities. Therefore, the experimental data show good reproducibility.< >
A novel moving object classification system using UWB radar and classifier based on decision tree structure are proposed. By using the proposed radar system, we construct UWB radar signal database by considering two movements and four moving directions of human and dog. The proposed classifier is based on nonlinear support vector machine (SVM) using RBF kernel and use linear predictive code (LPC) coefficients as feature vector. By evaluating performance of the proposed decision tree structures, we obtain the best classification results when the first level SVM classifies type of movement and then the second level SVM classifies moving object. The correct classification probability ranges from 93% up to 97%. The proposed system and classifier can be used for efficient human and dog classification and can be applied to other moving objects classification as well.
We systematically investigated the properties of metal contacts deposited on exfoliated β-Ga2O3 nanobelts. Unintentionally doped β-Ga2O3 was mechanically exfoliated from bulk β-Ga2O3 crystal and transferred onto SiO2/Si substrate having a back gate configuration. Electrodes were formed by depositing Ti/Au or Ni/Au onto the transferred β-Ga2O3 nanobelts, followed by rapid thermal annealing (RTA) with different ambient gases and temperatures. Using scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDS), it was shown that titanium reacts with oxygen to form titanium oxide, which has ohmic behavior. In contrast, nickel does not form an ohmic contact despite 600°C thermal treatment. The lower oxygen partial pressure in a nitrogen atmosphere as compared to air results in more oxygen vacancies within the Ga2O3 nanobelts during RTA and a negative threshold voltage shift. A decreased current level after high temperature annealing can be ascribed to significant outward diffusion of oxygen and gallium atoms and to oxidation of the metal electrode. Our results can pave a route to demonstrating high performance β-Ga2O3 nanobelt-based (opto)electronic devices.
Sunflower seed is a popular food, but plenty of bio-waste sunflower husks are discharged into the world. If this bio-waste trash can be recycled, it will be reduced not only environmental pollution but also the waste of resources. In this paper, a triboelectric nanogenerator (SFP-TENG) based on a bio-waste sunflower husk powder is proposed and its open-circuit voltage, short circuit current, and instantaneous power are archived as 488 V, 28.5μA, and 1200μW, respectively, under the frequency of 10 Hz with the excitation force of 58 N. The proposed SFP-TENG can harvest the biomechanical energy from the human body's daily motions. The fabricated SFP-TENG device is capable of lighting up 153 commercial LEDs. Furthermore, the SFP-TENG device is also tested under various humid environments such as 38, 49, 60, 79, and 89% relative humidity. Additionally, it can power up microelectronic devices such as calculator and stopwatch. Hence, we are sure that the proposed device can promote cost-effective and eco-friendly green energy harvesting through recycling bio-wastes as sunflower husk.
Abstract Researchers are striving to find the best possible ways to decompose or recycle generated waste to create a pollution‐free environment. Besides the problem of waste pollution, efficient energy generation is another challenging issue across the world. To counter both these problems in a single shot, a unique strategy of reusing and recycling trash soda cans and disposable plastic cups in a simple function change (Funchange) triboelectric nanogenerator (TENG) with a surplus advantage of no chemical processing is presented. The Funchange TENG device presents an excellent output performance with an open circuit voltage, short circuit current, and instantaneous power of 519 V, 82 µA, and 12.25 mW, correspondingly. Further, the fabricated nanogenerator exhibits excellent stability for about 72 000 cycles. This approach of applying trash materials for ultrarobust, high‐performance TENG will pave the path toward sustainable, facile, clean, and environmentally friendly energy scavenging.
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