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The micro crawling robot exhibits significant potential applications in various fields such as fault detection, disaster relief, and environmental monitoring. This article introduces a high‐performance millimeter scale crawling robot driven by a miniature electromagnetic linear actuator (MELA) with a body length of 5–6 mm and a mass of 80 mg. In this article, the working principle of the micro robot is analyzed and validated, and the influence of current, frequency, and angle α between the direction of actuator's force and the crawling surface on the crawling speed are analyzed through experiments. Results show that the optimal α ranges from 50° to 55°, and a specific current and frequency are identified to achieve maximum crawling speed for robot with particular α. When α is 50°, with a current of 300 mA and a frequency of 200 Hz, the robot reached the maximum speed of 20.2 Body Length s−1(BL s−1). The proposed robot can crawl at 12 BL s−1 with a load of 110 mg, and support a maximum load of 400 mg. Additionally, the robot demonstrated diverse capabilities such as climbing on a 10° slope with a load of 110 mg, jumping on a 1 mm obstacle, and crawling on surfaces of various materials. [ABSTRACT FROM AUTHOR]

Hydrophobicity has been developed in many areas, whose potentials in drag reduction at microscale have attracted numerous attentions for expanding the practical applications in fields of on chip devices, materials synthesis, and enhanced heat transfer. In this article, we select polydimethylsiloxane (PDMS) as the base material, whose hydrophobic modifications have been well developed. Among them, hydrofluoric acid treated one shows great performance and leads us to two types of microchannels, the straight and U-shaped, with enhanced hydrophobicity (from 91° to 106°). The coefficients of the pressure drop are experimentally measured with the Reynolds number ranging from 0 to 300. The results illustrate that the drag reduction rate reaches at 37.8% for the straight microchannel and 26.8% for the U-shaped microchannel. With the increase in the Reynolds number, the drag reduction effect stays almost constant for the straight channel, while it decreases gradually for the U-shaped channel. The flow impingement induced by a centrifugal force has an important impact on the slip effect that grows with the Re. Next, we adopt the numerical method and the micro-particle imaging velocimetry measurement to analyze the drag reduction effect from perspectives of the slip length. We successfully derive the slip length model correlating the drag reduction effect. Our results not only achieve substantial drag reduction in PDMS microchannels, but also provide a quantitative correlation between hydrophobicity and drag reduction, offering a feasible strategy for extensive applications at microscale, such as fluid actuation, bio-chip analysis, and highly efficient cooling system. [ABSTRACT FROM AUTHOR]

This paper reports a MEMS accelerometer based on bulk SiC. The fabrication and packaging scheme were designed, an efficient signal processing circuit was built, and the output performance of the sensor was tested. The test results show that the resistivity of the piezoresistive material is 194.40 Ω μm, the sensor's output sensitivity is 0.21 mV/g, the linearity is 99.8%, and the resonance frequency is 1636 Hz. Finally, the accelerometer was applied to the two ground vibration tests of aero‐engine, and the vibration signal of the turbine components and the test bed was successfully extracted. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Flowing characteristics of drag reduction are experimentally and numerically investigated with a combination of hydrophobic coating and various cavities in polydimethylsiloxane microchannels. Two typical types of cavities with different geometrical parameters, rectangular and triangular, are studied with a wide range of Reynolds numbers from 0 to 300. A promising hydrophobic processing method is proposed based on a comprehensive performance on surface morphology, water repellency, and structural distortion. In this method, hydrofluoric acid (40 wt. %) is adopted and the corrosion time is set to 5 min. The velocity field and streamlines are acquired by the micro-particle image velocimetry system and numerical models to explain the flow patterns in particular. The slip length is measured as 13.38 μm in the hydrophobic straight channel. For rectangular cavities, the drag reduction rate reaches nearly 14.1% under no-slip condition and 33.2% under slip condition. A critical turning point of the co-effect is found by numerical results when the slip length is about 15 μm, which is also determined by the cavities. The convergent and divergent angles of triangular cavities play a critical role in the pressure drop due to the competition of the vortex and flow impingement. A nonlinear model is developed based on the numerical results to predict Poiseuille number with the relevant important variables for a two-dimensional microchannel. Our results reveal the fundamental physics of flowing characteristics with the co-design of hydrophobicity and microstructures, predicting a composite design method for widespread applications in microfluids. [ABSTRACT FROM AUTHOR]

The most effective approach to subsidizing power producers in order to bolster the penetration of renewable energy is continuously debated. To address this issue, this paper undertakes an in‐depth investigation into a solar farm investment problem, aiming at capturing the common interests and frictions among the government, the solar system developer, and the utility. In this paper, both static and dynamic game models are proposed with the consideration of the uncertainty of solar power generation. Before investing in a solar farm project, a potential solar farm investor takes into account of subsidy rate regulation for utilities enacted by the government, the panel price announced by the solar developer. In this study, we identified two thresholds of solar panel cost, which provide valuable insights for government policymakers when formulating an appropriate subsidy rate for the solar energy industry. Besides, a optimal policy for each stakeholder has been exposed. The finding from the dynamic model discloses the profound influence of various behaviors on the long‐term profitability of each stakeholder. Finally, based on the real‐world solar power data in Orlando, a case study is presented to expose a more tangible prospect for industrial application. [ABSTRACT FROM AUTHOR]

Renewable portfolio standard (RPS) is a legislative requirement for regulating the utility to increase the output of renewable energy, however, it's not easy for the government to optimally design the target. To address this problem, this study investigates solar investing problems by theoretically investigating a novel game model. To meet the RPS requirement, the utility has to procure not only traditional energy but also solar energy. This paper aims to capture all the frictions among the stakeholders including the regulator, the utility and also a photovoltaic (PV) developer. The results show that the regulator can benefit from the strategy with higher RPS requirements if there is less resistance to regulation and a high penalty rate. Besides, the development of solar technology will increase the optimal PV panel price and investment in solar. Given a high requirement of renewable output, it's better off to increase the solar investment for more green output. This study also finds the developer enjoys a high requirement because it promotes the PV adoption and increases the panel price as well. Additionally, a dynamic system was developed to study the players' long-term behavior as well. The stable region and optimal strategy of behavior have been figured out. Interestingly, for the developer and the utility, a salutation of profit regarding the raising of the regulator's adjusting speed of decision is observed. Study a novel problem of solar investment. Capture the frictions among the stakeholders under the Renewable Portfolio Standard regulation. Reveal the optimal strategy for the players. Investigate the players' behavior in long term operations. Observe profit ramping phenomena for the developer and utility. [ABSTRACT FROM AUTHOR]