The problems of steady film condensation on a vertical surface embedded in a thin porous medium with anisotropic permeability filled with pure saturated vapour are studied analytically by using the Brinkman-Darcy flow model. The principal axes of anisotropic permeability are oriented in a direction that non-coincident with the gravity force. On the basis of the flow permeability tensor due to the anisotropic properties and the Brinkman-Darcy flow model adopted by considering negligible macroscopic and microscopic inertial terms, boundary-layer approximations in the porous liquid film momentum equation is solved analytically. Scale analysis is applied to predict the order-of-magnitudes involved in the boundary layer regime. The first novel contribution in the mathematics consists in the use of the anisotropic permeability tensor inside the expression of the mathematical formulation of the film condensation problem along a vertical surface embedded in a porous medium. The present analytical study reveals that the anisotropic permeability properties have a strong influence on the liquid film thickness, condensate mass flow rate and surface heat transfer rate. The comparison between thin and thick porous media is also presented.
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http://dx.doi.org/10.1186/2193-1801-3-659 | DOI Listing |
Langmuir
January 2025
College of Physical Science and Technology, Yangzhou University, Yangzhou 225002, China.
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Department of Biomedical Engineering, Faculty of Science and Engineering, Swansea University, Swansea, United Kingdom; Zienkiewicz Institute for Modelling Data and AI, Swansea University, Swansea, United Kingdom. Electronic address:
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View Article and Find Full Text PDFMaterials (Basel)
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Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation Science and Optoelectronics Engineering, Beihang University, Beijing 100191, China.
To achieve a near-zero magnetic field environment, the use of permalloy sheets with high-performance magnetic properties is essential. However, mainstream welding processes for magnetically shielded rooms (MSRs), such as argon arc welding and laser welding, can degrade the magnetic properties of the material. Additionally, neglecting the anisotropy of permalloy sheets can introduce unpredictable errors in the evaluation of MSR performance.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
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Department Smart Hybrid Materials Laboratory (SHMs), Department of Chemistry, Division of Physical Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
Ionic covalent organic framework (COF) nanosheets are becoming increasingly attractive as promising two-dimensional (2D) materials for proton transport due to their ionic functionality and tailor-made pores. However, most synthetic methods for nanosheets rely on surface-assisted methods or phase transformation often yielding nanosheets with low aspect ratios. In this study, we present a bottom-up approach utilizing an oil-oil-water triphase system to achieve the large-scale synthesis of ionic COF nanosheets.
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October 2024
National Metal and Materials Technology Center, National Science and Technology Development Agency (NSTDA), Ministry of Higher Education, Science, Research and Innovation, Khlong Luang 12120, Pathum Thani, Thailand.
This study investigates the crystallization, microstructure, and performance of poly(lactic acid)/poly(butylene succinate) (PLA/PBS) thin films processed through blown film extrusion and biaxial orientation (BO) at various blend ratios. Succinic anhydride (SA) was used to enhance interfacial adhesion in PLA-rich blends, while blends near 50/50 formed co-continuous phases without SA. Biaxial stretching and annealing, adjusted according to the crystallization behavior of PLA and PBS, significantly influenced crystallinity, crystallite size, and molecular orientation.
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