Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 33 for “"Limiting current"”.
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Electrodialysis of acetic acid fermentation broths
… that increasing the flow rate increased the limiting current density. There appeared to be no limiting current density for model acetate solutions.
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Mitigation of losses from hydrodynamic mixing in a hydrogen bromine Laminar flow battery
… and experimental results show a decrease in limiting current. However, for matching inlet velocities or flow rates experimental results show limiting current consistent with predictions that assume no mixing. This result shows a path forward achieving higher power density in the hydrogen …
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Ionic separation in electrodialysis : analyses of boundary layer, cationic partitioning, and overlimiting current
… across the spacer. The relationship between the current and potential under conditions of the competitive transport between mono- and di-valent cations was used to estimate the statistical parameters. An uncertainty model was developed for the steady-state ionic transport in a two-dimensional …
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Pitting corrosion of aluminum-alloys at aluminum(3) iron inclusions: The effect of local chemical environment and transport phenomena
… was adopted to calculate the oxygen reduction limiting current at intermetallics to explain the mechanism and predict the related electrochemical behavior. It is suggested that dissolved oxygen acts as a depassivator for the pitting on commercial aluminum alloys in an aerated NaCl solution.
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Emerging Electrochemical Technologies: Advanced Engineering Design
… chemical processes that govern these systems. Limiting current expressions for power-law fluids are derived for the rotating disk and channel electrodes. Practical guidelines on when it is appropriate to use those expressions are given, as well as guidelines on how reactor or sensor dimensions …
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Design of cost-optimized village-scale electrodialysis systems for brackish water desalination
… was created to predict the desalination rate, limiting current density, and total energy use in an ED system. The model agrees with experimental measurements across two diverse ED stack designs, differing in total membrane area, membrane manufacturers, and flow channel spacers. A …
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Exoelectrogenic biofilm growth in shearing flows
… for the first time that mass transport limiting current, chronoamperometry, and cyclic voltammetry in a rotating disk electrode are ideal for studying adhesion of microbes to metallic surfaces under shear. We study the adhesion of Escherichia coli, Bacillus subtilis, and 1 μm silica …
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Electrochemical engineering considerations for gas evolution in molten sulfide electrolytes
The current interrupt and galvanostatic electrochemical impedance spectroscopy techniques were utilized to characterize the ohmic, charge transfer, and mass transfer over-potential behavior of gas evolving electrodes in aqueous, molten chloride, and molten sulfide electrolyte solutions under …
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Modeling process dynamics in membrane-electrolyte-assemblies of chloralkali electrolyzers considering steric and hydration effects
… MEA. The simulation results also show that the limiting current regime in the more hydrated mixture occurs at the higher current density. This trend defines the local overshoots occurring during the transient. The non-linear relation between the mechanical stress acting on the membrane and the …
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Nonlinear ion transport at high electric currents in shock electrodialysis and ion-intercalation memories
… the nonlinear ion transport at high electric currents, in two applications: shock electrodialysis (shock ED) for ion separation, and ion-intercalation memories for in-memory computing. The two studies are both related to the concept of concentration polarization (CP) in electrochemistry, which …
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The effect of mass transport on deposit quality in copper electrowinning
… with similar boundary layer thicknesses. The current distribution was calculated with a finite element method and a Fourier series. Nodulation appears at 20-50% of the limiting current density, and this was termed the permissible current density. The amount of nodulation, as well as surface …
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Juvenile onset Recurrent Respiratory Papillomatosis (JoRRP) at Red Cross War Memorial Children’s Hospital, Cape Town: A 2-year review
Introduction: Juvenile onset recurrent respiratory papillomatosis (JoRRP) is the commonest benign paediatric neoplasm. There is no curative treatment, but the condition is self-limiting. Current primary treatment is aimed at symptomatic relief, comprising of serial surgical debulking of obstructive …
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Microchannel flow fields for polymer electrolyte fuel cells
… the effect on overall fuel cell performance and limiting current was investigated. Several diagnostic measurements including polarization curve, high frequency resistance, electrochemical impedance spectroscopy, pressure drop co-efficient and cell voltage monitoring were conducted to understand …
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Electropolishing of Niobium in Sulfuric Acid-Methanol Electrolytes: Development of Hydrofluoric Acid-Free Electrolytes
… acid (HF)-containing electrolytes is the currently accepted treatment process. The presence of HF is necessary for the removal of the passive oxide surface film formed in aqueous electrolytes. But HF is hazardous and must be contained without human exposure and eliminated in an …
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CMOS current amplifiers : speed versus nonlinearity
… integrated circuit design using various types of current-mode amplifiers. These circuits are analysed and realised using modern CMOS integration technologies. The dynamic nonlinearities of these circuits are discussed in detail as in the literature only linear nonidealities and static …
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Space-Charge Saturation and Current Limits in Cylindrical Drift Tubes and Planar Sheaths
… In high-power microwave devices using high-current, relativistic electron beams, it places a limit on the amount of radiation a device can produce. Because the beam's space-charge can actually reflect a portion of the beam, the ability to accurately predict the amount of current a device can …
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Effect of nano- fillers on tensile properties of biopolymer films
… However, their mechanical properties are limiting. Current research is focused on modifying the physical and chemical properties of biopolymers for better performance and broader applications. The addition of nanofillers has been proposed as a way to modify mechanical properties of …
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Control Strategies and Parameter Compensation for Permanent Magnet Synchronous Motor Drives
… boundaries of single speed motors, i.e. by limiting current and power to rated values. This results in under-utilization of the system, and places the motor at risk of excessive power losses. The constant power loss (CPL) concept is introduced in this dissertation as the correct basis for …
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Design and Modeling of a Novel Direct Carbon Molten Carbonate Fuel Cell with Porous Bed Electrodes
… recirculating electrolyte. In the cathode, co-current flow of electrolyte with entrained gases carbon dioxide and oxygen is sent in the upward direction through a porous bed grid. In the anode, co-current flow of a slurry of electrolyte entrained with carbon particles is sent in the downward …
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The Effect of Turbulent Flow on Corrosion of Mild Steel in High Partial CO<sub>2</sub> Environments
… behavior of TCFC was characterized using limiting current density technique. In the experiment, the limiting current density of API 5L X-65 carbon steel was measured at various velocities in 1 wt% NaCl electrolyte at pH 3.0 for each of the test temperatures of 30<sup>o</sup> C and …
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