There is increasing use of wood-based composites in industry not only because of the shortage of solid wood, but above all for their better properties such as: strength, aesthetic appearance, etc., compared to wood. Medium density fiberboard (MDF) is a wood-based composite that is widely used in the furniture industry. The goal of the research conducted was to determine the effect of the type of coating on the drill cutting blades on the value of thrust force (F), cutting torque (M), cutting tool temperature (T) and surface roughness of the hole in drilling MDF panels. In the tests, three types of carbide drills (HW) were used: not coated, TiAlN coated and ZrN coated. The measurement of both the thrust force and the cutting torque was carried out using an industrial piezoelectric sensor. The temperature of the cutting tool in the drilling process was measured using an industrial temperature measurement system using a K-type thermocouple. It was found that the value of the maximum temperature of the tool in the drilling process depends not only on the cutting speed and feed rate, but also on the type of coating of the cutting tool. The value of both the cutting torque and the thrust force is significantly influenced by the value of the feed rate and the type of drill coating. The effect of varying plate density on the surface roughness of the hole and the variation of the value of the thrust force is also discussed. The results of the investigations were statistically analyzed using a multi-factorial analysis of variance (ANOVA).
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http://dx.doi.org/10.3390/ma12030386 | DOI Listing |
Phys Rev Lett
December 2024
School of Physics and Astronomy, Institute of Natural Sciences and MOE-LSC, Shanghai Jiao Tong University, Shanghai 200240, China.
Chemically driven micromotors exhibit a pronounced affinity for nearby surfaces, yet the quantification of this motor-wall interaction strength remains unexplored in experiments. Here, we apply an external force to a self-electrophoretic micromotor which slides along a wall and measures the force necessary to disengage the motor from the wall. Our experiments unveil that the required disengaging force increases with the strength of chemical driving, often surpassing both the motor's effective gravity and its propulsive thrust.
View Article and Find Full Text PDFSci Rep
December 2024
School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang, 330013, Jiangxi, People's Republic of China.
Compared with simple formations, EPB (earth pressure balance) shield tunnelling in composite formations encounters severe problems with muck conditioning and require improved muck conditioning technology to fulfil expectations for continuous and efficient excavation. In the Nanchang Metro Line 4 Project, a water-rich sand-argillaceous siltstone composite formation is encountered. With a high moisture content and complex composite formation ratio, it is quite difficult to determine the optimum muck conditioning scheme, and thus, muck spewing accidents frequently occur during the tunnelling process.
View Article and Find Full Text PDFBiomimetics (Basel)
December 2024
College of Oceanography, Hohai University, Nanjing 210024, China.
In order to figure out the wall effect on the propulsive property of an auto-propelled foil, the commercial open-source code ANSYS Fluent was employed to numerically evaluate the fluid dynamics of flexible foil under various wall distances. A virtual model of NACA0015 foil undergoing travelling wavy motion was adopted, and the research object included 2D and 3D models. To capture the foil's moving boundary, the dynamic grid technique coupled with the overlapping grid was utilized to realize the foil's positive deformation and passive forward motion.
View Article and Find Full Text PDFIntroduction Movement requires maneuvers that generate thrust to either make turns or move the body forward in physical space. The computational space for perpetually controlling the relative position of every point on the body surface can be vast. We hypothesize the evolution of efficient design for movement that minimizes active (neural) control by leveraging the passive (reactive) forces between the body and the surrounding medium at play.
View Article and Find Full Text PDFNanoscale
December 2024
Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing, 210096, P. R. China.
CsPbBr perovskite has garnered significant attention in the field of optoelectronics due to its exceptional photoelectric properties. In this study, we report the fabrication of a piezoelectric nanogenerator (PNG) composed of a composite of monoclinic phase CsPbBr nanocrystals and polydimethylsiloxane. This is the first instance of a PNG based on the monoclinic phase of CsPbBr.
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