The Experts below are selected from a list of 39870 Experts worldwide ranked by ideXlab platform
Aimy Bazylak - One of the best experts on this subject based on the ideXlab platform.
-
Modeling the Effect of Fibre Surface Morphology on Liquid Water Transport in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers
Transport in Porous Media, 2018Co-Authors: Hang Liu, Stéphane Chevalier, Chunghyuk Lee, James Hinebaugh, Rupak Banerjee, Aimy BazylakAbstract:In this work, we present a novel methodology for incorporating the effect of Fibre Surface morphology on liquid water transport in polymer electrolyte membrane fuel cell gas diffusion layers (GDLs). Roughness features presented on the Surface of the Fibre are analysed using atomic force microscopy and are found to significantly impact the capillary pressure of liquid water pathways propagating through the GDL. A threshold capillary pressure was defined as the largest capillary pressure exhibited by the liquid water phase during the invasion of the throat. The threshold capillary pressures observed in the presence of roughness features are significantly greater than those in the absence of roughness features. Two-dimensional circumferential roughness models in cylindrical and converging-diverging throats are established, and an interfacial meniscus advancing algorithm is presented to determine the resulting threshold capillary pressures required for liquid water penetration. Revised Young–Laplace equations, which are particularly useful for pore network modeling, are suggested for calculating threshold capillary pressures that account for the effect of the roughness of throats with intrinsic contact angles greater than $$90^{\circ }$$ 90 ∘ .
-
the impact of Fibre Surface morphology on the effective thermal conductivity of a polymer electrolyte membrane fuel cell gas diffusion layer
Journal of Power Sources, 2014Co-Authors: S J Botelho, Aimy BazylakAbstract:Abstract In this work, the effect of Fibre Surface morphology on the effective thermal conductivity of the gas diffusion layer of a polymer electrolyte membrane fuel cell is presented. Atomic force microscopy was used to measure the Fibre Surface roughness and asperity height distributions for various Fibres for Toray carbon paper. Hertzian contact mechanics was used to determine individual micro-contact areas and thermal resistances, and results were compared with the smooth cylinder approximation. The effective thermal contact resistance between rough Fibres was determined using resistance network theory. The thermal contact resistance and total contact area were determined for various angles of Fibre orientation and contact forces; results are presented as empirical formulations. It was found that the effective thermal contact resistance is significantly affected by Fibre roughness features when compared to the smooth Fibre case, which is often used in the literature. The analysis conducted provides an alternative to computationally expensive Surface feature analyses by providing a tool which can be used to implement the nano-scale features of gas diffusion layer Fibres into existing effective thermal conductivity models.
-
the impact of Fibre Surface morphology on the effective thermal conductivity of a pem fuel cell gas diffusion layer
224th ECS Meeting (October 27 – November 1 2013), 2013Co-Authors: S J Botelho, Aimy BazylakAbstract:In this work, the preliminary findings for determining the effect of Fibre Surface morphology on the effective thermal conductivity of the gas diffusion layer of a polymer electrolyte membrane fuel cell is presented. Atomic force microscopy was used to measure the Fibre Surface roughness and asperity height distribution for various Fibres and locations along each Fibre for Toray carbon paper TGP-H-120. The thermal contact resistance was measured using preliminary methods, which will be further advanced in the near future. Hertzian contact mechanics was used to validate the results obtained, and to compare with smooth Fibre thermal contact resistance for rough and smooth Fibres. The thermal contact resistance was determined for various angles of Fibre orientation and contact forces; it was determined that values for rough Fibre contact are on average twice that of the contact of smooth Fibres.
Chao Tang - One of the best experts on this subject based on the ideXlab platform.
-
fabrication of al2o3 nano structure functional film on a cellulose insulation polymer Surface and its space charge suppression effect
Polymers, 2017Co-Authors: Yanqing Li, Ruijin Liao, Qiang Liao, Chao TangAbstract:Cellulose insulation polymer (paper/pressboard) has been widely used in high voltage direct current (HVDC) transformers. One of the most challenging issues in the insulation material used for HVDC equipment is the space charge accumulation. Effective ways to suppress the space charge injection/accumulation in insulation material is currently a popular research topic. In this study, an aluminium oxide functional film was deposited on a cellulose insulation pressboard Surface using reactive radio frequency (RF) magnetron sputtering. The sputtered thin film was characterized by the scanning electron microscopy/energy dispersive spectrometer (SEM/EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The influence of the deposited functional film on the dielectric properties and the space charge injection/accumulation behaviour was investigated. A preliminary exploration of the space charge suppression effect is discussed. SEM/EDS, XPS, and XRD results show that the nano-structured Al2O3 film with amorphous phase was successfully fabricated onto the Fibre Surface. The cellulose insulation pressboard Surface sputtered by Al2O3 film has lower permittivity, conductivity, and dissipation factor values in the lower frequency (<103 Hz) region. The oil-impregnated sputtered pressboard presents an apparent space-charge suppression effect. Compared with the pressboard sputtered with Al2O3 film for 90 min, the pressboard sputtered with Al2O3 film for 60 min had a better space charge suppression effect. Ultra-small Al2O3 particles (<10 nm) grew on the Surface of the larger nanoparticles. The nano-structured Al2O3 film sputtered on the Fibre Surface could act as a functional barrier layer for suppression of the charge injection and accumulation. This study offers a new perspective in favour of the application of insulation pressboard with a nano-structured function Surface against space charge injection/accumulation in HVDC equipment.
-
fabrication of al o nano structure functional film on a cellulose insulation polymer Surface and its space charge suppression effect
Polymers, 2017Co-Authors: Jia Hao, Qiang Liao, Ruiji Liao, Guoyong Liu, Chao TangAbstract:Cellulose insulation polymer (paper/pressboard) has been widely used in high voltage direct current (HVDC) transformers. One of the most challenging issues in the insulation material used for HVDC equipment is the space charge accumulation. Effective ways to suppress the space charge injection/accumulation in insulation material is currently a popular research topic. In this study, an aluminium oxide functional film was deposited on a cellulose insulation pressboard Surface using reactive radio frequency (RF) magnetron sputtering. The sputtered thin film was characterized by the scanning electron microscopy/energy dispersive spectrometer (SEM/EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The influence of the deposited functional film on the dielectric properties and the space charge injection/accumulation behaviour was investigated. A preliminary exploration of the space charge suppression effect is discussed. SEM/EDS, XPS, and XRD results show that the nano-structured Al₂O₃ film with amorphous phase was successfully fabricated onto the Fibre Surface. The cellulose insulation pressboard Surface sputtered by Al₂O₃ film has lower permittivity, conductivity, and dissipation factor values in the lower frequency (<10³ Hz) region. The oil-impregnated sputtered pressboard presents an apparent space-charge suppression effect. Compared with the pressboard sputtered with Al₂O₃ film for 90 min, the pressboard sputtered with Al₂O₃ film for 60 min had a better space charge suppression effect. Ultra-small Al₂O₃ particles (<10 nm) grew on the Surface of the larger nanoparticles. The nano-structured Al₂O₃ film sputtered on the Fibre Surface could act as a functional barrier layer for suppression of the charge injection and accumulation. This study offers a new perspective in favour of the application of insulation pressboard with a nano-structured function Surface against space charge injection/accumulation in HVDC equipment.
Christopher R Lowe - One of the best experts on this subject based on the ideXlab platform.
-
single mode optical Fibre Surface plasma wave chemical sensor
Sensors and Actuators B-chemical, 1997Co-Authors: A J C Tubb, F P Payne, Roger Bradley Millington, Christopher R LoweAbstract:Abstract We describe a new design of optical Fibre Surface plasma wave chemical sensor. The basic sensor consists of a tapered single-mode optical Fibre with a thin layer of silver evaporated onto the tapered section. The gradually changing diameter of the Fibre along the taper and the variation in silver depth around the taper result in a distributed coupling between the guided mode of the Fibre and the Surface plasma wave. As a result, the coupling to the Surface plasma wave occurs over an enlarged spectral range. The device shows good sensitivity to refractive index with refractive index changes of 5 × 10 −4 being detectable. The device is compact, simple to make, and has applications as a biochemical or immunosensor.
-
single mode optical Fibre Surface plasma wave chemical sensor
Progress in Fibre Optic Sensors and Their Applications IEE Colloquium on, 1995Co-Authors: A J C Tubb, F P Payne, Roger Bradley Millington, Christopher R LoweAbstract:We have demonstrated a new type of single mode optical Fibre plasma wave sensor with a very broad spectral response ranging over 400 nm. This is achieved by a distributed phase matching between the Fibre and plasma modes, resulting from the tapering of the Fibre. The optimum response of this device is around 750 nm, and can detect changes in refractive index as low as 5/spl times/10/sup -4/.
S J Botelho - One of the best experts on this subject based on the ideXlab platform.
-
the impact of Fibre Surface morphology on the effective thermal conductivity of a polymer electrolyte membrane fuel cell gas diffusion layer
Journal of Power Sources, 2014Co-Authors: S J Botelho, Aimy BazylakAbstract:Abstract In this work, the effect of Fibre Surface morphology on the effective thermal conductivity of the gas diffusion layer of a polymer electrolyte membrane fuel cell is presented. Atomic force microscopy was used to measure the Fibre Surface roughness and asperity height distributions for various Fibres for Toray carbon paper. Hertzian contact mechanics was used to determine individual micro-contact areas and thermal resistances, and results were compared with the smooth cylinder approximation. The effective thermal contact resistance between rough Fibres was determined using resistance network theory. The thermal contact resistance and total contact area were determined for various angles of Fibre orientation and contact forces; results are presented as empirical formulations. It was found that the effective thermal contact resistance is significantly affected by Fibre roughness features when compared to the smooth Fibre case, which is often used in the literature. The analysis conducted provides an alternative to computationally expensive Surface feature analyses by providing a tool which can be used to implement the nano-scale features of gas diffusion layer Fibres into existing effective thermal conductivity models.
-
the impact of Fibre Surface morphology on the effective thermal conductivity of a pem fuel cell gas diffusion layer
224th ECS Meeting (October 27 – November 1 2013), 2013Co-Authors: S J Botelho, Aimy BazylakAbstract:In this work, the preliminary findings for determining the effect of Fibre Surface morphology on the effective thermal conductivity of the gas diffusion layer of a polymer electrolyte membrane fuel cell is presented. Atomic force microscopy was used to measure the Fibre Surface roughness and asperity height distribution for various Fibres and locations along each Fibre for Toray carbon paper TGP-H-120. The thermal contact resistance was measured using preliminary methods, which will be further advanced in the near future. Hertzian contact mechanics was used to validate the results obtained, and to compare with smooth Fibre thermal contact resistance for rough and smooth Fibres. The thermal contact resistance was determined for various angles of Fibre orientation and contact forces; it was determined that values for rough Fibre contact are on average twice that of the contact of smooth Fibres.
Qiang Liao - One of the best experts on this subject based on the ideXlab platform.
-
fabrication of al2o3 nano structure functional film on a cellulose insulation polymer Surface and its space charge suppression effect
Polymers, 2017Co-Authors: Yanqing Li, Ruijin Liao, Qiang Liao, Chao TangAbstract:Cellulose insulation polymer (paper/pressboard) has been widely used in high voltage direct current (HVDC) transformers. One of the most challenging issues in the insulation material used for HVDC equipment is the space charge accumulation. Effective ways to suppress the space charge injection/accumulation in insulation material is currently a popular research topic. In this study, an aluminium oxide functional film was deposited on a cellulose insulation pressboard Surface using reactive radio frequency (RF) magnetron sputtering. The sputtered thin film was characterized by the scanning electron microscopy/energy dispersive spectrometer (SEM/EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The influence of the deposited functional film on the dielectric properties and the space charge injection/accumulation behaviour was investigated. A preliminary exploration of the space charge suppression effect is discussed. SEM/EDS, XPS, and XRD results show that the nano-structured Al2O3 film with amorphous phase was successfully fabricated onto the Fibre Surface. The cellulose insulation pressboard Surface sputtered by Al2O3 film has lower permittivity, conductivity, and dissipation factor values in the lower frequency (<103 Hz) region. The oil-impregnated sputtered pressboard presents an apparent space-charge suppression effect. Compared with the pressboard sputtered with Al2O3 film for 90 min, the pressboard sputtered with Al2O3 film for 60 min had a better space charge suppression effect. Ultra-small Al2O3 particles (<10 nm) grew on the Surface of the larger nanoparticles. The nano-structured Al2O3 film sputtered on the Fibre Surface could act as a functional barrier layer for suppression of the charge injection and accumulation. This study offers a new perspective in favour of the application of insulation pressboard with a nano-structured function Surface against space charge injection/accumulation in HVDC equipment.
-
fabrication of al o nano structure functional film on a cellulose insulation polymer Surface and its space charge suppression effect
Polymers, 2017Co-Authors: Jia Hao, Qiang Liao, Ruiji Liao, Guoyong Liu, Chao TangAbstract:Cellulose insulation polymer (paper/pressboard) has been widely used in high voltage direct current (HVDC) transformers. One of the most challenging issues in the insulation material used for HVDC equipment is the space charge accumulation. Effective ways to suppress the space charge injection/accumulation in insulation material is currently a popular research topic. In this study, an aluminium oxide functional film was deposited on a cellulose insulation pressboard Surface using reactive radio frequency (RF) magnetron sputtering. The sputtered thin film was characterized by the scanning electron microscopy/energy dispersive spectrometer (SEM/EDS), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The influence of the deposited functional film on the dielectric properties and the space charge injection/accumulation behaviour was investigated. A preliminary exploration of the space charge suppression effect is discussed. SEM/EDS, XPS, and XRD results show that the nano-structured Al₂O₃ film with amorphous phase was successfully fabricated onto the Fibre Surface. The cellulose insulation pressboard Surface sputtered by Al₂O₃ film has lower permittivity, conductivity, and dissipation factor values in the lower frequency (<10³ Hz) region. The oil-impregnated sputtered pressboard presents an apparent space-charge suppression effect. Compared with the pressboard sputtered with Al₂O₃ film for 90 min, the pressboard sputtered with Al₂O₃ film for 60 min had a better space charge suppression effect. Ultra-small Al₂O₃ particles (<10 nm) grew on the Surface of the larger nanoparticles. The nano-structured Al₂O₃ film sputtered on the Fibre Surface could act as a functional barrier layer for suppression of the charge injection and accumulation. This study offers a new perspective in favour of the application of insulation pressboard with a nano-structured function Surface against space charge injection/accumulation in HVDC equipment.