Fouling is one of the common problems in heat-transfer applications, resulting in higher fouling resistance, and lower heat-transfer coefficient. This paper introduces the design and fabrication of an Fe–Al coating with micro/nanostructures on low-carbon steel by electrical discharge coating (EDC) technology to improve the antifouling property. The Fe–Al coating with micro/nanostructures is characterized by a large number of micro/nanostructures and superior anti-fouling property, which is attributed to its hydrophobic surface. The antifouling property, fouling induction period and contact angle of the Fe–Al coating with micro/nanostructures increase with the increasing gap voltage. Compared with the polished surface of low-carbon steel, the Fe–Al coating with micro/nanostructures extends the induction period from 214 to 1350 min, with a heat flux of 98 kW·m−2. After 50 adhesion tests, the contact angle of the Fe–Al coating with micro/nanostructures decreases from 6.81% to 27.52%, which indicates that the Fe–Al coating with micro/nanostructures is durable and suitable for industrial applications.
This paper investigates the failure of a regulating valve stem in a petrochemical plant, which was mainly caused by vibration fatigue under small opening conditions. The fractured valve stem was analyzed using macroscopic analysis, chemical composition analysis, mechanical property analysis, metallographic analysis, fracture surface observation, and energy spectrum analysis. Additionally, fluid-structure interaction (FSI) modal analysis was used to investigate the failure of the regulating valve. The results indicate that the valve opening had a direct impact on the vibration of the valve body, which, when operated at small openings, led to fatigue fracture at the step of variable cross-section. The paper suggests a smooth transition treatment be performed at the variable cross-section of the valve stem to avoid stress concentration. Although this study is limited to a specific case, it provides valuable insights for the failure analysis of valves operating at small openings.
The use of eye movements for identifying intrinsic human psychological changes is a hot topic, and the identification of eye states in specific scenarios is the basis for analyzing the test taker's instantaneous psychological response state and thus for testing implicit driving quality deficits. Infrared eye images are difficult to visualize eye movements, and traditional eye image processing results are not suitable for eye state analysis. In order to make the eye images show the eye movements, a feature extraction method based on contours and key point is proposed for infrared eye images. To extract the eye contour features, the iris and eyelid contours are extracted based on the variation of gray values between the points located on the boundary and their surroundings; for the extraction of eye key point features, a network design with a combination of dlib and residual structure is used to extract the pupil and eyelid key points, respectively. The experimental results show that the method can represent the relative positions of the pupil, iris and eyelid separately with little computational effort, which can intuitively show the eye movement and thus reduce the stress of subsequent eye state recognition.
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