Global ETD Search
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Showing 1 to 20 of 38 for “"diffusion layer"”.
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Investigation of Water Transport Parameters and Processes in the Gas Diffusion Layer of PEM Fuel Cells
… the water transport characteristics of the gas diffusion layer (GDL) of proton exchange membrane fuel cells (PEMFCs). Additionally, experimental fixtures and procedures for the determination of the constitutive relationships are presented. The water transport relationships are incorporated into …
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Nucleation Dynamics for Water Condensation on Hydrophobic Surfaces in the Presence of Non-Condensable Gases
… density rate by forming a vapor-depleted gas diffusion layer. Therefore, this work studied the relationship between nucleation density rate and supersaturation ratio during dropwise condensation on subcooled smooth hydrophobic surfaces with the presence of non-condensable gases in a …
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Reactive Plasma Etching of Silicon Carbide, Silicon Carbonitride, and Titanium Nitride in a Tetrafluoroethane/Oxygen Plasma
In this study we investigate the etching of the diffusion barrier between the silicon substrate and the 1ow-k dielectric material. We will use silicon carbide (SiC), silicon carbonitride (SiCN), and titanium nitride (TiN) as our diffusion layer. Using the RF plasma and the magnetron gun with …
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Investigating Cathode–Electrolyte Interfacial Degradation Mechanism to Enhance the Performance of Rechargeable Aqueous Batteries
… on the particle, which can regulate the proton diffusion and Mn dissolution behavior. Our study discovers the dynamic Mn D/R process and highlights the impact of coating strategy in the performance of aqueous batteries. In Chapter 4, we investigate the diffusion layer formed by transition metals …
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Hybrid fuel cell for mobile devices : an integrated approach
… and methanol concentration, and cathode gas diffusion layer (GDL) were performed on two standard membrane electrode assemblies (MEA). In addition, an MEA was modified using polyvinyl alcohol (PVA) to test its effect on decreasing methanol crossover for improved fuel cell performance.
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Understanding Electrode-Electrolyte Interfaces with Metal Dissolution and Redeposition Chemistry
… cycling conditions. Amorphous TiO2 surface layers can be formed on WO3 electrodes by adding exotic Ti cations to the electrolyte, and slow electrochemical cycling. The dissolution and redeposition of electrodes and surface coatings are intertwined, helping to establish a …
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Evaluation of the Effect of Microporous Sublayer Design and Fabrication on Performance and Adhesion in PEM Fuel Cell Assemblies
… exchange membrane fuel cell (PEMFC) contains a layer called the microporous sublayer (MSL). The MSL is a mixture of carbon black and polytetrafluoroethylene (PTFE), which is typically applied to the gas diffusion layer (GDL). The composition (wt.% PTFE) and loading (mg/cm2) can be varied to …
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Free air breathing planar PEM fuel cell design for portable electronics
… cathode electrode, anode electrode, and gas diffusion layer on both sides of the membrane to assume the role of GDL and current collector. This planar fuel cell design was able to produce a power density over 25mW/cm2. This is an order of magnitude lower then reported air breathing fuel cell …
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Performance Characteriztion and Modeling of a Passive Direct Methanol Fuel Cell (DMFC) over a Range of Operating Temperatures and Relative Humidities
… methanol fuel cells is flooding of the cathode diffusion layer.
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The kinetics of liquid-liquid extraction of metals in a rotating diffusion cell. A rotating diffusion cell is used to study the rates of extraction of divalent transition metals by di-(2-ethylhexyl)-phosphoric acid and a sulphur analogue. A chemical-diffusion model describes the rate curves.
A rotating diffusion cell (RDC) has been used to study the kinetics of extraction of the transition metals cobalt (II), nickel (II), copper (II) and zinc (II) from sulphate solutions into either of two extractants held in n-heptane; di-(2-ethylhexyl) phosphoric acid (D2EHPA) or di-(2- ethylhexyl) …
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Factors Affecting Redox Magnetohydrodynamics for Flow in Small Volumes
… that the magnetic force resides primarily in the diffusion layer in these systems, not in the electrolyte between the counter and working electrodes. The effects of channel and working electrode geometry also supported this conclusion. The outcome has important ramifications in designing …
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Evaluation of the Effects of Microporous Layer Characteristics and Assembly Parameters on the Performance and Durability of a Planar PEM Fuel Cell
… and optimizing the functions of the microporous layer (MPL). Researchers have found that including this layer, composed of carbon black and TeflonTM (PTFE), between the gas diffusion layer (GDL) and catalyst layer (CL) of PEMFCs improves performance. The major benefit of the MPL in conventional …
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Thermal Analysis and Cation Doping of Nafion Membranes
… for</p> <p>comparison. Virgin and used gas diffusion layer (GDL), catalyst coated membrane</p> <p>(CCM), and uncatalyzed membrane (UCM) materials were examined to aid in single cell</p> <p>post-test characterization where separation of materials is difficult and may alter results.</p> …
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Electrochemical Analysis of Oxidation of Primary Amines to Ketones with 3,5-Di-Tert-Butyl-1,2Benzoquinone
… electrode reactions and the effect of the diffusion layer. The first chapter of this thesis discusses the importance of a class of electroactive compounds known as quinones and their role in some biologically and chemically related redox reactions. Followed by a comparison of the …
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Magnetic nanoparticles : synthesis, characterization, applications and systematic study of exchanging biasing
… low temperature due to small clusters of Co in a diffusion layer around the Co core. We interpret these effects using a simple phenomenological model and propose a method for fabricating magnetic media using exchange biased nanoparticles. We further investigated the defect moments in the CoO shell …
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A comprehensive fractal approach in determination of the effective thermal conductivity of gas diffusion layers in polymer electrolyte membrane fuel cells
… of the effectiveness thermal conductivity of gas diffusion layers (GDL) used in polymer electrolyte membrane fuel cells (PEMFC‟s). This is one of the factors affecting the durability of a fuel cell and need to get a solution to minimize costs and optimize the use of electrodes and cells. The main …
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The modification of fuel cell-based breath alcohol sensor materials to improve water retention of sensing performance
… significantly less water. Finally, the catalyst layer and gas diffusion layer (GDL) were investigated. For the catalyst layer, platinum black and 20% platinum supported on carbon achieved similar results. The choice of catalyst was less of an issue than the choice of GDL. It was found that using …
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Water management strategies for polymer electrolyte fuel cells (PEFCs) employing microchannel flowfields
… inhibits reactant gas transport to the catalyst layer, leading to a phenomenon called flooding. Flooding causes a rapid drop in cell voltage and is detrimental to fuel cell performance and durability. Microchannel flowfield designs possess characteristics which could potentially improve water …
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Fate of emerging organic contaminants in Chinese wastewater treatment plants
… as the binding agent and agarose gel as the diffusion layer. The performance of DGT sampler (indicated by ratio of DGT-measured concentrations (CDGT) to the directly-measured concentration (Cb), the ratio of CDGT/Cb ranged from 0.9 to 1.1 indicating the excellent performance of DGT) in …
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