Turbulence is widely expected to limit the confinement and, thus, the overall performance of modern neoclassically optimized stellarators. We employ novel petaflop-scale gyrokinetic simulations to predict the distribution of turbulence fluctuations and the related transport scaling on entire stellarator magnetic surfaces and reveal striking differences to tokamaks. Using a stochastic global-search optimization method, we derive the first turbulence-optimized stellarator configuration stemming from an existing quasiomnigenous design.
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http://dx.doi.org/10.1103/PhysRevLett.113.155001 | DOI Listing |
Water Res
January 2025
School of Water Conservancy and Transportation, Zhengzhou University, Zhengzhou, China; Yellow River Laboratory, Zhengzhou University, Zhengzhou, China.
Sediment control is a major concern in sewer management. Early studies focused on the parameters affecting the efficiency of existing dredging facilities, and novel long-term sediment reduction measures have not been developed. Superior sediment reduction performance has been demonstrated for plates folded at 25° placed in a pipe.
View Article and Find Full Text PDFSmall Methods
January 2025
The First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, 150001, China.
Mass production of biomedical microrobots demands expensive and complex preparation techniques and versatile biocompatible materials. Learning from natural bacteria flagella, the study demonstrates a magnetic polymer multilayer cylindrical microrobot that bestows the controllable propulsion upon an external rotating magnetic field with uniform intensity. The magnetic microrobots are constructed by template-assisted layer-by-layer technique and subsequent functionalization of magnetic particles onto the large opening of the microrobots.
View Article and Find Full Text PDFF1000Res
January 2025
Department of Aeronautical & Automobile Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, 576104, India.
Background: Centrifugal compressors are dynamic machines utilizing a rotating impeller, efficiently accelerate incoming gases, transforming kinetic energy into pressure energy for compression. They serve a wide range of industries, including air conditioning, refrigeration, gas turbines, industrial processes, and applications such as air compression, gas transportation, and petrochemicals, demonstrating their versatility. Designing a centrifugal compressor poses challenges related to achieving high aerodynamic efficiency, surge and choke control, material selection, rotor dynamics, cavitation, erosion, and addressing environmental considerations while balancing costs.
View Article and Find Full Text PDFHeliyon
January 2025
Department of Mechanical Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran.
Background: The development of heat transfer devices used for heat conversion and recovery in several industrial and residential applications has long focused on improving heat transfer between two parallel plates. Numerous articles have examined the relevance of enhancing thermal performance for the system's performance and economics. Heat transport is improved by increasing the Reynolds number as the turbulent effects grow.
View Article and Find Full Text PDFJ Acoust Soc Am
January 2025
Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027, China.
Leading-edge serrations inspired by owls exhibit the capability to control airfoil-turbulence interaction noise, but the design principle of the serration shape is still an open issue. To this end, we designed five types of serration shapes with different combinations of curvature, namely, triangular, ogee, anti-ogee, feather-like, and anti-feather-like. These curves are applied to serrated modifications with different bluntness levels (sharp or blunt) and amplitudes (0.
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