subject:(Diffusion limited water transport)

Georgia Tech

1. Carnevale, Kevin A. Finite-Difference Model of Cell Dehydration During Cryopreservation.

Degree: MS, Mechanical Engineering, 2004, Georgia Tech

► A numerical model for describing the kinetics of intracellular water transport during cryopreservation was developed. As ice is formed outside the cell, depleting the extracellular… (more)

Subjects/Keywords: Cryobiology; Cryopreservation; Membrane permeability; Vitrification; Membrane-limited water transport; Diffusion-limited water transport; Crank-Nicolson; Biot number; Peclet number; Dimensional analysis; Cell dehydration; Mathematical models; Finite differences

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APA (6^th Edition):

Carnevale, K. A. (2004). Finite-Difference Model of Cell Dehydration During Cryopreservation. (Masters Thesis). Georgia Tech. Retrieved from http://hdl.handle.net/1853/7258

Chicago Manual of Style (16^th Edition):

Carnevale, Kevin A. “Finite-Difference Model of Cell Dehydration During Cryopreservation.” 2004. Masters Thesis, Georgia Tech. Accessed April 11, 2021. http://hdl.handle.net/1853/7258.

MLA Handbook (7^th Edition):

Carnevale, Kevin A. “Finite-Difference Model of Cell Dehydration During Cryopreservation.” 2004. Web. 11 Apr 2021.

Vancouver:

Carnevale KA. Finite-Difference Model of Cell Dehydration During Cryopreservation. [Internet] [Masters thesis]. Georgia Tech; 2004. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1853/7258.

Council of Science Editors:

Carnevale KA. Finite-Difference Model of Cell Dehydration During Cryopreservation. [Masters Thesis]. Georgia Tech; 2004. Available from: http://hdl.handle.net/1853/7258

University of Cincinnati

2. YIN, CHUKAI. A NEW FLUX-LIMITED DIFFUSION METHOD FOR NEUTRAL PARTICLE TRANSPORT CALCULATIONS.

Degree: PhD, Engineering : Nuclear and Radiological Engineering, 2005, University of Cincinnati

URL: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1129768153

► The Boltzmann equation, which is often used to describe neutral particle transport process, is impossible to solve analytically in most cases. Solving the equation by… (more)

▼ The Boltzmann equation, which is often used to describe neutral particle transport process, is impossible to solve analytically in most cases. Solving the equation by a numerically method could also be very time-consuming for some problems. Therefore, various approximation methods have been developed for particle transport calculations. In this dissertation, a new Flux-Limited diffusion method (DM) is investigated as a low-order approximation to the transport equation. Specifically, the new Flux-Limited diffusion method (DM) is derived based on the Minerbo maximum entropy Eddington factor and corresponding boundary conditions are developed. Performance of the DM method is tested for a variety of particle transport problems: including steady-state problems, transient problems, one-dimensional problems, two-dimensional problems, flux distribution problems, eigen-value problems, one-group problems, and two-group problems. The tests demonstrate that compared with other approximations, the DM method has the following good features. (1) The DM method is a low order approximation as the classic diffusion method but can improve the accuracy of classic diffusion method by a factor up to 10. (2) The DM method has relatively fast computing speed compared with other high order approximations and its computation cost is not too expensive compared with the classic diffusion method. (3) The DM method can predict proper traveling speed of particles in time-dependent problems. (4) The DM method is valid for neutral particle transport in systems containing strong absorbers, regions near particle sources or boundaries, and systems where strongly anisotropic scattering of particles occur. (5) The DM method is superior to other Flux-Limited diffusion methods available in the literature. (6) The solutions of the DM method are numerically stable in all the circumstances. Overall, the DM method is promising as a low-order approximation for particle transport calculations in some applications. Advisors/Committee Members: Dr. Su, Bingjing (Advisor).

Subjects/Keywords: Engineering, Nuclear; Boltzmann Equation; Particle Transport; Flux-Limited Diffusion

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APA (6^th Edition):

YIN, C. (2005). A NEW FLUX-LIMITED DIFFUSION METHOD FOR NEUTRAL PARTICLE TRANSPORT CALCULATIONS. (Doctoral Dissertation). University of Cincinnati. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=ucin1129768153

Chicago Manual of Style (16^th Edition):

YIN, CHUKAI. “A NEW FLUX-LIMITED DIFFUSION METHOD FOR NEUTRAL PARTICLE TRANSPORT CALCULATIONS.” 2005. Doctoral Dissertation, University of Cincinnati. Accessed April 11, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1129768153.

MLA Handbook (7^th Edition):

YIN, CHUKAI. “A NEW FLUX-LIMITED DIFFUSION METHOD FOR NEUTRAL PARTICLE TRANSPORT CALCULATIONS.” 2005. Web. 11 Apr 2021.

Vancouver:

YIN C. A NEW FLUX-LIMITED DIFFUSION METHOD FOR NEUTRAL PARTICLE TRANSPORT CALCULATIONS. [Internet] [Doctoral dissertation]. University of Cincinnati; 2005. [cited 2021 Apr 11]. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1129768153.

Council of Science Editors:

YIN C. A NEW FLUX-LIMITED DIFFUSION METHOD FOR NEUTRAL PARTICLE TRANSPORT CALCULATIONS. [Doctoral Dissertation]. University of Cincinnati; 2005. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1129768153

Australian National University

3. Tattersall, Wade. Positron cross sections and transport in water .

Degree: 2016, Australian National University

URL: http://hdl.handle.net/1885/127374

► A detailed understanding of the behaviour of positrons and electrons as they pass through liquids is critical for a number of applications, from positron emission… (more)

▼ A detailed understanding of the behaviour of positrons and electrons as they pass through liquids is critical for a number of applications, from positron emission tomography and ion therapy to cosmic ray detectors and materials characterisation. In particular, transport in liquid water is vital for medical applications because of its similarity to human tissue, and is an area of continued research. This thesis presents newly measured experimental cross sections for positrons in water as well as several Monte Carlo simulation techniques aimed at improving our models of positron and electron transport. In particular, special efforts have been made to model the effects of elastic coherent scattering, which arise due to the position and velocity correlations between molecules in liquids and other dense media. The experimental scattering results include the first measurements of integral and differential elastic positron cross sections for water vapour, as well as detailed grand total and positronium formation cross sections for the same. Performed on the positron beamline apparatus at the Australian National University, this transmission experiment passed a high-resolution beam of positrons through a scattering cell containing water vapour. The parallel component of the energy of the positrons after scattering was analysed to determine the ratio between the scattered and unscattered portions of the beam, from which absolute total cross sections were calculated. The experiment further utilised a differentiated magnetic field to separate elastic scattering from the other scattering processes, and to distinguish between scattering angles in order to measure angle-differential cross sections. An original Monte Carlo track-structure simulation code has been written which aims to precisely model the transport behaviour of electrons and positrons in dilute gases, dense gases and liquids. This simulation incorporates several new features to improve its ability to model systems with high particle loss rates, varying electric fields and fully-differential ionisation interactions. Each feature has been rigorously tested against benchmark systems from the literature and, where necessary, against Boltzmann equation solutions of new benchmark systems. The simulation has also been applied to model elements of the positron trapping apparatus which is a critical component of the positron scattering experiment. The simulation's validity has been extended beyond dilute gases by including a treatment of the coherent elastic scattering that is caused by the structure of dense media. Following the theories of Van Hove, Cohen and Lekner, either a static or dynamic structure factor can be combined with gas-phase cross sections to form a modified scattering cross section that partially accounts …

Subjects/Keywords: positron; scattering; water; swarm; transport; Monte Carlo; diffusion; energy deposition

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APA (6^th Edition):

Tattersall, W. (2016). Positron cross sections and transport in water . (Thesis). Australian National University. Retrieved from http://hdl.handle.net/1885/127374

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Tattersall, Wade. “Positron cross sections and transport in water .” 2016. Thesis, Australian National University. Accessed April 11, 2021. http://hdl.handle.net/1885/127374.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Tattersall, Wade. “Positron cross sections and transport in water .” 2016. Web. 11 Apr 2021.

Vancouver:

Tattersall W. Positron cross sections and transport in water . [Internet] [Thesis]. Australian National University; 2016. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1885/127374.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Tattersall W. Positron cross sections and transport in water . [Thesis]. Australian National University; 2016. Available from: http://hdl.handle.net/1885/127374

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Alberta

4. Zubik, Jakub Tadeusz. Computational Study of the Water Cycle at the Surface of Mars.

Degree: MS, Department of Mechanical Engineering, 2012, University of Alberta

URL: https://era.library.ualberta.ca/files/qr46r109z

► To understand the water cycle on Mars, details of mass and energy transfer between the surface and the atmosphere are of importance. A complete model,… (more)

Subjects/Keywords: Radiation; CFD; Regolith; Thermal diffusion; Fog; Phoenix Mission; Terrestrial Water; Mass Transport; Diffusion; Frost; Mars; Porous Media; Thermo-diffusion; Numerical Methods

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zubik, J. T. (2012). Computational Study of the Water Cycle at the Surface of Mars. (Masters Thesis). University of Alberta. Retrieved from https://era.library.ualberta.ca/files/qr46r109z

Chicago Manual of Style (16^th Edition):

Zubik, Jakub Tadeusz. “Computational Study of the Water Cycle at the Surface of Mars.” 2012. Masters Thesis, University of Alberta. Accessed April 11, 2021. https://era.library.ualberta.ca/files/qr46r109z.

MLA Handbook (7^th Edition):

Zubik, Jakub Tadeusz. “Computational Study of the Water Cycle at the Surface of Mars.” 2012. Web. 11 Apr 2021.

Vancouver:

Zubik JT. Computational Study of the Water Cycle at the Surface of Mars. [Internet] [Masters thesis]. University of Alberta; 2012. [cited 2021 Apr 11]. Available from: https://era.library.ualberta.ca/files/qr46r109z.

Council of Science Editors:

Zubik JT. Computational Study of the Water Cycle at the Surface of Mars. [Masters Thesis]. University of Alberta; 2012. Available from: https://era.library.ualberta.ca/files/qr46r109z

McMaster University

5. Sharpe, Jason. Innovative Analysis Techniques for Canadian SCWR Neutronics.

Degree: PhD, 2017, McMaster University

URL: http://hdl.handle.net/11375/22064

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Knowledge of the effects of nuclear data uncertainties and physics approximations is crucial for the development, design, operation, and accident mitigation, of nuclear power plants.… (more)

Subjects/Keywords: physics; neutronics; engineering; nuclear; scwr; canadian; reactor; super; critical; water-cooled; diffusion; experiment; transport; technique

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APA (6^th Edition):

Sharpe, J. (2017). Innovative Analysis Techniques for Canadian SCWR Neutronics. (Doctoral Dissertation). McMaster University. Retrieved from http://hdl.handle.net/11375/22064

Chicago Manual of Style (16^th Edition):

Sharpe, Jason. “Innovative Analysis Techniques for Canadian SCWR Neutronics.” 2017. Doctoral Dissertation, McMaster University. Accessed April 11, 2021. http://hdl.handle.net/11375/22064.

MLA Handbook (7^th Edition):

Sharpe, Jason. “Innovative Analysis Techniques for Canadian SCWR Neutronics.” 2017. Web. 11 Apr 2021.

Vancouver:

Sharpe J. Innovative Analysis Techniques for Canadian SCWR Neutronics. [Internet] [Doctoral dissertation]. McMaster University; 2017. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/11375/22064.

Council of Science Editors:

Sharpe J. Innovative Analysis Techniques for Canadian SCWR Neutronics. [Doctoral Dissertation]. McMaster University; 2017. Available from: http://hdl.handle.net/11375/22064

University of Texas – Austin

6. Geise, Geoffrey Matthew. Water and salt transport structure/property relationships in polymer membranes for desalination and power generation applications.

Degree: PhD, Chemical Engineering, 2012, University of Texas – Austin

URL: http://hdl.handle.net/2152/26083

► Providing sustainable supplies of water and energy is a critical global challenge. Polymer membranes dominate desalination and could be crucial to power generation applications, which… (more)

▼ Providing sustainable supplies of water and energy is a critical global challenge. Polymer membranes dominate desalination and could be crucial to power generation applications, which include reverse osmosis (RO), nanofiltration (NF), forward osmosis (FO), pressure-retarded osmosis (PRO), electrodialysis (ED), membrane capacitive deionization (CDI), and reverse electrodialysis (RED). Improved membranes with tailored water and salt transport properties are required to extend and optimize these technologies. Water and salt transport structure/property relationships provide the fundamental framework for optimizing polymer materials for membrane applications. The water and salt transport and free volume properties of a series of sulfonated styrenic pentablock copolymers were characterized. The polymers' water uptake and water permeability increase with degree of sulfonation, and the block molecular weights could be used to tune water uptake, permeability, and selectivity properties. The presence of fixed charge groups, i.e., sulfonate groups, on the polymer backbone influence the material's salt transport properties. Specifically, the salt permeability increases strongly with increasing salt concentration, and this increase is a result of increases in both salt sorption and diffusivity with salt concentration. The data for the sulfonated polymers, including a sulfonated polysulfone random copolymer, are compared to those for an uncharged polymer to determine the influence of polymer charge on salt transport properties. The sulfonated styrenic pentablock copolymer permeability data are compared to literature data using the water permeability and water/salt selectivity tradeoff relationship. Fundamental transport property comparisons can be made using this relationship. The effect of osmotic de-swelling on the polymers and the transport properties of composite membranes made from sulfonated styrenic pentablock copolymers are also discussed. The sulfonated styrenic pentablock copolymers were exposed to multi-valent ions to determine their effect on the polymer's salt transport properties. Magnesium chloride permeability depends less on upstream salt concentration than sodium chloride permeability, presumably due to stronger association between the sulfonate groups and magnesium compared to sodium ions. Triethylaluminum was used to neutralize the polymer's sulfonic acid functionality and presumably cross-link the polymer. The mechanical, transport, and free volume properties of these aluminum neutralized polymers were studied. Advisors/Committee Members: Paul, Donald R. (advisor), Freeman, B. D. (Benny D.) (advisor).

Subjects/Keywords: Membrane; Solution diffusion; Polymer; Ionomer; Transport; Desalination; Water and salt transport; Sulfonated polymer; Structure/property relationships

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APA (6^th Edition):

Geise, G. M. (2012). Water and salt transport structure/property relationships in polymer membranes for desalination and power generation applications. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/26083

Chicago Manual of Style (16^th Edition):

Geise, Geoffrey Matthew. “Water and salt transport structure/property relationships in polymer membranes for desalination and power generation applications.” 2012. Doctoral Dissertation, University of Texas – Austin. Accessed April 11, 2021. http://hdl.handle.net/2152/26083.

MLA Handbook (7^th Edition):

Geise, Geoffrey Matthew. “Water and salt transport structure/property relationships in polymer membranes for desalination and power generation applications.” 2012. Web. 11 Apr 2021.

Vancouver:

Geise GM. Water and salt transport structure/property relationships in polymer membranes for desalination and power generation applications. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2012. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2152/26083.

Council of Science Editors:

Geise GM. Water and salt transport structure/property relationships in polymer membranes for desalination and power generation applications. [Doctoral Dissertation]. University of Texas – Austin; 2012. Available from: http://hdl.handle.net/2152/26083

7. Faurel, Michaël. Conception et mise en place d'expériences de diffusion de l'eau et de solutés dans des milieux poreux modèles d'argiles gonflantes : Design and assessment of water and solute species diffusion experiments on model porous media of swelling clays.

Degree: Docteur es, Terre solide et enveloppe superficielle, 2012, Poitiers

URL: http://www.theses.fr/2012POIT2320

►

La plupart des données existantes de diffusion d'eau et de solutés sont obtenues pour des roches argileuses extrêmement complexes ou des échantillons en apparence plus… (more)

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La plupart des données existantes de diffusion d'eau et de solutés sont obtenues pour des roches argileuses extrêmement complexes ou des échantillons en apparence plus simples préparés à base d'argiles gonflantes sodiques de type smectite. Ces dernières pouvant présenter des organisations très variables et encore mal comprises (phase gel-floc-suspension stable) en conditions saturées, il reste très difficile de contraindre les modèles à double milieu (eau porale ou interfoliaire) parfois avancés pour interpréter des expériences de diffusion. Un système modèle d'argiles gonflantes reflétant réellement un double milieu a pu être obtenu à partir de trois fractions granulométriques d'une vermiculite-Na. Celles-ci ne présentent pas de phase gel en conditions saturées mais des particules bien définies dont la morphologie et l'organisation ont pu être caractérisées. Un dispositif de diffusion a été développé afin d'étudier la diffusion de HDO et Br- pour ces différentes fractions en fonction de la porosité. L'avantage majeur de ce dispositif est de pouvoir préparer des échantillons par sédimentation analysables en tomographie de rayons-X afin de valider leur homogénéité organisationnelle ; hypothèse considérée dans les modélisations. Les résultats obtenus démontrent que cette nouvelle voie de préparation conduit à des échantillons plus homogènes par rapport aux méthodes classiques. Les premières perspectives quant à l'utilisation de ces doubles milieux modèles se dégagent à travers les premiers résultats de diffusion obtenus puisque leurs caractéristiques géométriques parfaitement contrôlées peuvent permettre de pondérer l'impact des différents processus de transport potentiels

Most of existing data on diffusion of water and solutes were obtained either on extremely complex clayey rocks or on seemingly more simple samples prepared from sodium-saturated swelling clay minerals, namely smectites. Because these latter can exhibit in water-saturated conditions various organizations not yet fully understood (gel phase-floc-stable suspension), it is still difficult to constrain dual-porosity media modeling (pore or interlayer water) sometimes considered for interpreting results from diffusion experiments. A model system for swelling clay minerals, mimicking a true dual-porosity medium, was obtained by using three size fractions of a Na-vermiculite. These fractions do not exhibit gel-like behavior in water-saturated conditions but rather well defined particles, whose morphology and organization have been characterized. An experimental set-up was designed for the investigation of HDO and Br- diffusion in these size-fractions as a function of porosity. The main advantage of this set up is that it allows assessing for the organizational homogeneity of a sample prepared by sedimentation process through X-ray tomography measurements, an assumption considered for diffusion modeling. The obtained results showed that this new method for sample preparation leads to more homogeneous samples as compared to classical procedures. The first…

Advisors/Committee Members: Meunier, Alain (thesis director), Prêt, Dimitri (thesis director).

Subjects/Keywords: Argile gonflante; Diffusion; Milieu poreux; Eau; Solutés; Transport réactif; Microstructure; Swelling clay; Diffusion; Porous medium; Water; Solute species; Reactive transport; Microstructure; 553.6

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APA (6^th Edition):

Faurel, M. (2012). Conception et mise en place d'expériences de diffusion de l'eau et de solutés dans des milieux poreux modèles d'argiles gonflantes : Design and assessment of water and solute species diffusion experiments on model porous media of swelling clays. (Doctoral Dissertation). Poitiers. Retrieved from http://www.theses.fr/2012POIT2320

Chicago Manual of Style (16^th Edition):

Faurel, Michaël. “Conception et mise en place d'expériences de diffusion de l'eau et de solutés dans des milieux poreux modèles d'argiles gonflantes : Design and assessment of water and solute species diffusion experiments on model porous media of swelling clays.” 2012. Doctoral Dissertation, Poitiers. Accessed April 11, 2021. http://www.theses.fr/2012POIT2320.

MLA Handbook (7^th Edition):

Faurel, Michaël. “Conception et mise en place d'expériences de diffusion de l'eau et de solutés dans des milieux poreux modèles d'argiles gonflantes : Design and assessment of water and solute species diffusion experiments on model porous media of swelling clays.” 2012. Web. 11 Apr 2021.

Vancouver:

Faurel M. Conception et mise en place d'expériences de diffusion de l'eau et de solutés dans des milieux poreux modèles d'argiles gonflantes : Design and assessment of water and solute species diffusion experiments on model porous media of swelling clays. [Internet] [Doctoral dissertation]. Poitiers; 2012. [cited 2021 Apr 11]. Available from: http://www.theses.fr/2012POIT2320.

Council of Science Editors:

Faurel M. Conception et mise en place d'expériences de diffusion de l'eau et de solutés dans des milieux poreux modèles d'argiles gonflantes : Design and assessment of water and solute species diffusion experiments on model porous media of swelling clays. [Doctoral Dissertation]. Poitiers; 2012. Available from: http://www.theses.fr/2012POIT2320

8. Mikkola, Mikko. Studies on Limiting Factors of Polymer Electrolyte Membrane Fuel Cell Cathode Performance.

Degree: 2007, Helsinki University of Technology

URL: http://lib.tkk.fi/Diss/2007/isbn9789512285907/

►

Fuel cells are electrochemical devices that convert the chemical energy of fuel into electricity and heat. Polymer electrolyte membrane fuel cells (PEMFCs) are a type… (more)

▼

Fuel cells are electrochemical devices that convert the chemical energy of fuel into electricity and heat. Polymer electrolyte membrane fuel cells (PEMFCs) are a type of fuel cells which use a proton conducting polymer membrane as the electrolyte. PEMFCs are envisioned to replace conventional power sources in many applications, including transportation, stationary distributed and backup power generation, and portable devices. This work concentrated on the limiting factors of the PEMFC cathode performance, focusing on mass transport and water management. Overpotential of oxygen reduction reaction was outside the scope of this thesis. The main study subject was the porous transport layer (PTL). Physical properties of the PTL have a significant effect on reactant and reaction product transport, as well as electrical and thermal fluxes. PTL research concentrated on three main areas, characterization of PTL media, correlation of PTL physical properties to fuel cell performance, and the effects of inhomogeneous compression distribution. An improved method for PTL characterization was developed and used to investigate the performance of PTL materials under different operating conditions. It was observed that the flooding on the cathode side begins in the PTL, not the electrode itself. A clear relation between PTL properties and fuel cell performance could not be established. Inhomogeneous compression of PTLs was found to cause local variations in the mass transport properties, electrical conductivity and contact resistance at various interfaces. A method for determining the bulk conductivity of the PTL and the contact resistance at the PTL-flow field plate interface as a function of compression was developed. The applicability of titanium sinters as porous transport layers for free-breathing PEMFC was investigated. The mechanical properties of titanium sinters were found acceptable, but due to high hydrophilicity, the sinter was prone to flooding. Furthermore, contact resistance between the sinter and other components was high. The effect of sodium chloride on PEMFC performance was investigated experimentally and found to cause an irreversible performance loss. Sodium ions were found to replace protons in the electrolyte membrane and thus increase resistance. Chloride ions were not observed to interfere with fuel cell operation under the conditions used in the experiments.

Polttokennot ovat sähkökemiallisia laitteita, jotka muuntavat polttoaineen kemiallisen energian suoraan sähköksi ja lämmöksi. Polymeeripolttokenno on polttokennotyyppi, jossa elektrolyyttinä käytetään protonijohtavaa polymeerikalvoa. Polymeeripolttokennojen odotetaan korvaavan perinteiset teholähteet monissa käyttökohteissa, mm. ajoneuvoissa, hajautetussa energiantuotannossa, varavoimanlähteissä ja kannettavissa laitteissa. Tässä työssä tutkittiin polymeeripolttokennon katodin suorituskykyä rajoittavia tekijöitä keskittyen aineensiirtoon ja vedenhallintaan. Hapen pelkistysreaktion häviöt jätettiin tarkastelun ulkopuolelle. Pääasiallisena…

Advisors/Committee Members: Helsinki University of Technology, Department of Engineering Physics and Mathematics, Laboratory of Advanced Energy Systems.

Subjects/Keywords: PEMFC; cathode; porous transport layer; gas diffusion layer; water management; impurities; polymeeripolttokenno; katodi; kaasudiffuusiokerros; vedenhallinta; virrankatkaisu; virrantiheysjakauma

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APA (6^th Edition):

Mikkola, M. (2007). Studies on Limiting Factors of Polymer Electrolyte Membrane Fuel Cell Cathode Performance. (Thesis). Helsinki University of Technology. Retrieved from http://lib.tkk.fi/Diss/2007/isbn9789512285907/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Mikkola, Mikko. “Studies on Limiting Factors of Polymer Electrolyte Membrane Fuel Cell Cathode Performance.” 2007. Thesis, Helsinki University of Technology. Accessed April 11, 2021. http://lib.tkk.fi/Diss/2007/isbn9789512285907/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Mikkola, Mikko. “Studies on Limiting Factors of Polymer Electrolyte Membrane Fuel Cell Cathode Performance.” 2007. Web. 11 Apr 2021.

Vancouver:

Mikkola M. Studies on Limiting Factors of Polymer Electrolyte Membrane Fuel Cell Cathode Performance. [Internet] [Thesis]. Helsinki University of Technology; 2007. [cited 2021 Apr 11]. Available from: http://lib.tkk.fi/Diss/2007/isbn9789512285907/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Mikkola M. Studies on Limiting Factors of Polymer Electrolyte Membrane Fuel Cell Cathode Performance. [Thesis]. Helsinki University of Technology; 2007. Available from: http://lib.tkk.fi/Diss/2007/isbn9789512285907/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Toronto

9. Muirhead, Daniel. Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers.

Degree: 2017, University of Toronto

URL: http://hdl.handle.net/1807/79319

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In this thesis, the relative humidity (RH) of the cathode reactant gas was investigated as a factor which influences gas diffusion layer (GDL) liquid water… (more)

Subjects/Keywords: Gas diffusion layer; Oxygen transport resistance; Polymer electrolyte membrane fuel cells; Saturation; Synchrotron X-ray radiography; Water management; 0548

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APA (6^th Edition):

Muirhead, D. (2017). Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers. (Masters Thesis). University of Toronto. Retrieved from http://hdl.handle.net/1807/79319

Chicago Manual of Style (16^th Edition):

Muirhead, Daniel. “Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers.” 2017. Masters Thesis, University of Toronto. Accessed April 11, 2021. http://hdl.handle.net/1807/79319.

MLA Handbook (7^th Edition):

Muirhead, Daniel. “Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers.” 2017. Web. 11 Apr 2021.

Vancouver:

Muirhead D. Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers. [Internet] [Masters thesis]. University of Toronto; 2017. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1807/79319.

Council of Science Editors:

Muirhead D. Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers. [Masters Thesis]. University of Toronto; 2017. Available from: http://hdl.handle.net/1807/79319

Michigan Technological University

10. Mortazavi, Mehdi. WATER TRANSPORT THROUGH POROUS MEDIA AND IN FLOW CHANNELS OF PROTON EXCHANGE MEMBRANE FUEL CELL.

Degree: PhD, Department of Mechanical Engineering-Engineering Mechanics, 2014, Michigan Technological University

URL: https://digitalcommons.mtu.edu/etds/856

► Proton exchange membrane (PEM) fuel cell has been known as a promising power source for different applications such as automotive, residential and stationary. During… (more)

▼ Proton exchange membrane (PEM) fuel cell has been known as a promising power source for different applications such as automotive, residential and stationary. During the operation of a PEM fuel cell, hydrogen is oxidized in anode and oxygen is reduced in the cathode to produce the intended power. Water and heat are inevitable byproducts of these reactions. The water produced in the cathode should be properly removed from inside the cell. Otherwise, it may block the path of reactants passing through the gas channels and/or gas diffusion layer (GDL). This deteriorates the performance of the cell and eventually can cease the operation of the cell. Water transport in PEM fuel cell has been the subject of this PhD study. Water transport on the surface of the GDL, through the gas flow channels, and through GDL has been studied in details. For water transport on the surface of the GDL, droplet detachment has been measured for different GDL conditions and for anode and cathode gas flow channels. Water transport through gas flow channels has been investigated by measuring the two-phase flow pressure drop along the gas flow channels. As accumulated liquid water within gas flow channels resists the gas flow, the pressure drop increases along the flow channels. The two-phase flow pressure drop can reveal useful information about the amount of liquid water accumulated within gas flow channels. Liquid water transport though GDL has also been investigated by measuring the liquid water breakthrough pressure for the region between the capillary fingering and the stable displacement on the drainage phase diagram. The breakthrough pressure has been measured for different variables such as GDL thickness, PTFE/Nafion content within the GDL, GDL compression, the inclusion of a micro-porous layer (MPL), and different water flow rates through the GDL. Prior to all these studies, GDL microstructural properties have been studied. GDL microstructural properties such as mean pore diameter, pore diameter distribution, and pore roundness distribution have been investigated by analyzing SEM images of GDL samples. Advisors/Committee Members: Kazuya Tajiri.

Subjects/Keywords: Water transport; gas diffusion layer (GDL); Proton exchange membrane (PEM); PEM flow channels; two-phase flow; Energy Systems

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APA (6^th Edition):

Mortazavi, M. (2014). WATER TRANSPORT THROUGH POROUS MEDIA AND IN FLOW CHANNELS OF PROTON EXCHANGE MEMBRANE FUEL CELL. (Doctoral Dissertation). Michigan Technological University. Retrieved from https://digitalcommons.mtu.edu/etds/856

Chicago Manual of Style (16^th Edition):

Mortazavi, Mehdi. “WATER TRANSPORT THROUGH POROUS MEDIA AND IN FLOW CHANNELS OF PROTON EXCHANGE MEMBRANE FUEL CELL.” 2014. Doctoral Dissertation, Michigan Technological University. Accessed April 11, 2021. https://digitalcommons.mtu.edu/etds/856.

MLA Handbook (7^th Edition):

Mortazavi, Mehdi. “WATER TRANSPORT THROUGH POROUS MEDIA AND IN FLOW CHANNELS OF PROTON EXCHANGE MEMBRANE FUEL CELL.” 2014. Web. 11 Apr 2021.

Vancouver:

Mortazavi M. WATER TRANSPORT THROUGH POROUS MEDIA AND IN FLOW CHANNELS OF PROTON EXCHANGE MEMBRANE FUEL CELL. [Internet] [Doctoral dissertation]. Michigan Technological University; 2014. [cited 2021 Apr 11]. Available from: https://digitalcommons.mtu.edu/etds/856.

Council of Science Editors:

Mortazavi M. WATER TRANSPORT THROUGH POROUS MEDIA AND IN FLOW CHANNELS OF PROTON EXCHANGE MEMBRANE FUEL CELL. [Doctoral Dissertation]. Michigan Technological University; 2014. Available from: https://digitalcommons.mtu.edu/etds/856

University of Toronto

11. Liu, Hang. Liquid Water Transport Behavior in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers due to Material Degradation and Fibre Surface Morphology.

Degree: PhD, 2018, University of Toronto

URL: http://hdl.handle.net/1807/92122

► Understanding the liquid water transport behavior in the polymer electrolyte membrane fuel cell gas diffusion layers (GDLs) is essential for improving cell performance and durability.… (more)

▼ Understanding the liquid water transport behavior in the polymer electrolyte membrane fuel cell gas diffusion layers (GDLs) is essential for improving cell performance and durability. However, the uncontrolled decrease in GDL hydrophobicity has been found within a short portion of the expected operation lifetime. This decreased hydrophobicity can lead to an undesirably high level of liquid water accumulation within the GDL, resulting in performance losses. Furthermore, the impact of the microscale fibre surface morphology on pore-scale liquid water transport is not fully understood. The aim of this thesis is to investigate the impacts of GDL degradation and fibre surface morphology on liquid water transport. Synchrotron X-ray radiography and pore network modeling approaches were employed to perform in situ liquid water visualization and transport modeling, respectively. An ex situ accelerated carbon-corrosion-based stand-alone GDL degradation procedure was developed. The GDL was degraded as evidenced by a reduction in the GDL contact angle, which was associated with surface corrosion. Next, the impacts of GDL degradation on liquid water distributions were investigated. It was concluded that the increases in liquid water accumulation at component interfaces resulted in the reduced performance, which was attributed to the reduction in GDL hydrophobicity. The contributions of carbon fibre substrate and microporous layer (MPL) degradation were differentiated. The MPL degradation had the most significant impacts on the electrochemical performance and liquid water distributions within the GDL. Lastly, a novel methodology for incorporating fibre surface morphology to simulate liquid water transport in GDLs was presented. This model provides the foundation for future investigations of degradation-influenced liquid water transport at the pore-scale of the GDL. The main findings of this thesis provide new insights into the direct effects of GDL degradation into liquid water transport in the GDL, which are vital for designing next generation GDLs for improved durability. Advisors/Committee Members: Bazylak, Aimy, Mechanical and Industrial Engineering.

Subjects/Keywords: Electrochemical System; Gas Diffusion Layer; Liquid Water Transport; Material Degradation; Polymer Electrolyte Membrane Fuel Cell; Synchrotron Imaging; 0548

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APA (6^th Edition):

Liu, H. (2018). Liquid Water Transport Behavior in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers due to Material Degradation and Fibre Surface Morphology. (Doctoral Dissertation). University of Toronto. Retrieved from http://hdl.handle.net/1807/92122

Chicago Manual of Style (16^th Edition):

Liu, Hang. “Liquid Water Transport Behavior in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers due to Material Degradation and Fibre Surface Morphology.” 2018. Doctoral Dissertation, University of Toronto. Accessed April 11, 2021. http://hdl.handle.net/1807/92122.

MLA Handbook (7^th Edition):

Liu, Hang. “Liquid Water Transport Behavior in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers due to Material Degradation and Fibre Surface Morphology.” 2018. Web. 11 Apr 2021.

Vancouver:

Liu H. Liquid Water Transport Behavior in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers due to Material Degradation and Fibre Surface Morphology. [Internet] [Doctoral dissertation]. University of Toronto; 2018. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1807/92122.

Council of Science Editors:

Liu H. Liquid Water Transport Behavior in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers due to Material Degradation and Fibre Surface Morphology. [Doctoral Dissertation]. University of Toronto; 2018. Available from: http://hdl.handle.net/1807/92122

University of Toronto

12. Lee, Jongmin. X-ray Investigations of Liquid Water Transport in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers.

Degree: PhD, 2017, University of Toronto

URL: http://hdl.handle.net/1807/80981

► Understanding the liquid water transport behaviour in a polymer electrolyte membrane (PEM) fuel cell is key to achieving high performance. The gas diffusion layer (GDL)… (more)

▼ Understanding the liquid water transport behaviour in a polymer electrolyte membrane (PEM) fuel cell is key to achieving high performance. The gas diffusion layer (GDL) provides transport pathways for electrons, reactant gases, and product water. However, when liquid water accumulates within the pores of the GDL, the effective porosity of the material is decreased, resulting in a reduced effective diffusivity of reactant gases. This can lead to reactant starvation at the catalyst during high current density operation, causing significant efficiency losses. The aim of this thesis is to investigate the impact of the GDL microstructural properties on water transport in an operating fuel cell. Synchrotron X-ray radiography was used as a probing tool for identifying the water distribution in the GDL in situ. The role of the microporous layer (MPL) on liquid water management was identified through investigating in-plane water distribution in the GDL. Nanopores of the MPL reduced the amount and the size of water clusters in the GDL. Next, the influence of MPL thickness on the water accumulation in the GDL was investigated. The application of a thick MPL on the carbon fibre substrate resulted in less water content at the MPL-substrate interface than that in the GDL with a thin MPL. The effect of substrate thickness was also studied in terms of the fuel cell performance and liquid water distribution. The fuel cell incorporating a thin substrate exhibited superior electrochemical performance; however, unusual material movements were observed in the synchrotron images. It was concluded that the thin substrate was not able to provide necessary mechanical support to prevent material movements (e.g. membrane swell). Lastly, performance benefit of an MPL based on multiwall carbon nanotubes (MWCNTs) was studied. The MWCNTs additive to the MPL resulted in a high-porosity GDL compared to the conventional MPL. The high porosity region was prone to liquid water accumulation, but it also facilitated improved oxygen transport. The main findings of this thesis provide insights to fuel cell manufactures for design next generation GDLs. Advisors/Committee Members: Bazylak, Aimy, Mechanical and Industrial Engineering.

Subjects/Keywords: Computed tomography; Gas diffusion layer; Liquid water transport; Polymer electrolyte membrane fuel cell; Porous medium; Synchrotron imaging; 0363

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APA (6^th Edition):

Lee, J. (2017). X-ray Investigations of Liquid Water Transport in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers. (Doctoral Dissertation). University of Toronto. Retrieved from http://hdl.handle.net/1807/80981

Chicago Manual of Style (16^th Edition):

Lee, Jongmin. “X-ray Investigations of Liquid Water Transport in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers.” 2017. Doctoral Dissertation, University of Toronto. Accessed April 11, 2021. http://hdl.handle.net/1807/80981.

MLA Handbook (7^th Edition):

Lee, Jongmin. “X-ray Investigations of Liquid Water Transport in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers.” 2017. Web. 11 Apr 2021.

Vancouver:

Lee J. X-ray Investigations of Liquid Water Transport in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers. [Internet] [Doctoral dissertation]. University of Toronto; 2017. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1807/80981.

Council of Science Editors:

Lee J. X-ray Investigations of Liquid Water Transport in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers. [Doctoral Dissertation]. University of Toronto; 2017. Available from: http://hdl.handle.net/1807/80981

Loughborough University

13. Jinuntuya, Fontip. Numerical investigation of the structure effects on water transportation in PEMFC gas diffusion layers using X-ray tomography based Lattice Boltzmann method.

Degree: PhD, 2015, Loughborough University

URL: http://hdl.handle.net/2134/16587

► The excessive presence of liquid water in a gas diffusion layer (GDL) hinders the access of reactant gases to the active sites of the catalyst… (more)

▼ The excessive presence of liquid water in a gas diffusion layer (GDL) hinders the access of reactant gases to the active sites of the catalyst layer leading to decreased performance of a polymer electrolyte membrane fuel cell (PEMFC). Therefore, GDLs are usually treated with a hydrophobic agent to render their fibres more hydrophobic in order to facilitate gas transport and water removal. Numerous studies have been conducted to investigate water transport in PEMFCs in recent years; however, the behaviour of liquid water in a GDL at a pore-level is poorly understood. Macroscopic models fail to incorporate the influence of the structural morphology of GDLs on liquid water transport behaviour. Experimental methods are not conducive towards a good understanding at a microscopic level because of the diminutive size of the GDLs porous structure. Alternatively, the Lattice Boltzmann (LB) method has gathered interest as it is found to be particularly useful in fluid flow simulations in porous media due to its capability to incorporate the complex boundaries of actual GDL structures. To date, most studies on fluid transport in GDLs integrated artificial structures generated by stochastic simulation techniques to the LB models. The stochastic-based model, however, does not represent closely the microscopic features of the actual GDL as manufactured. In addition, comparison of liquid water transport behaviour in different GDL structures using the LB method is rare since only a single GDL material has been utilised in most of those studies. This thesis aims to develop our understanding of liquid water transport behaviour in GDLs with morphologically different structures under varying wettability conditions based on the LB method and the X-ray computed tomography (XCT) technique. GDLs with paper and felt structures were reconstructed into 3D digital volumetric models via the XCT process. The digital models were then incorporated into a LB solver to model water saturation distribution through the GDL domains. The GDL wettability was also altered so that the effect on liquid water behaviour in the GDL could be examined. This project is divided into three main sections. In the sensitivity analysis, the effect of image resolution on gas permeability through the X-ray reconstructed GDL was carried out using a single-phase LB model. It was found that the resolution variation could significantly affect the resulting gas permeability in both principal and off-principal directions, as well as computational time. An optimum resolution, however, exists at 2.72 μm/pixel, which consumed 400 times less computational time with less than 8% difference in the resulting permeability compared to the base resolution. This study also served as a guideline for selecting a resolution for generating the XCT images of the GDLs which were utilised in the following studies. In the structure analysis, the structures of the paper and felt GDLs were generated using the XCT and the key properties of each GDL, including thickness, porosity, permeability and…

Subjects/Keywords: 621.31; Gas diffusion layer (GDL); PEMFC; Lattice Boltzmann method; X-ray tomography; Water transport; Structure effect

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APA (6^th Edition):

Jinuntuya, F. (2015). Numerical investigation of the structure effects on water transportation in PEMFC gas diffusion layers using X-ray tomography based Lattice Boltzmann method. (Doctoral Dissertation). Loughborough University. Retrieved from http://hdl.handle.net/2134/16587

Chicago Manual of Style (16^th Edition):

Jinuntuya, Fontip. “Numerical investigation of the structure effects on water transportation in PEMFC gas diffusion layers using X-ray tomography based Lattice Boltzmann method.” 2015. Doctoral Dissertation, Loughborough University. Accessed April 11, 2021. http://hdl.handle.net/2134/16587.

MLA Handbook (7^th Edition):

Jinuntuya, Fontip. “Numerical investigation of the structure effects on water transportation in PEMFC gas diffusion layers using X-ray tomography based Lattice Boltzmann method.” 2015. Web. 11 Apr 2021.

Vancouver:

Jinuntuya F. Numerical investigation of the structure effects on water transportation in PEMFC gas diffusion layers using X-ray tomography based Lattice Boltzmann method. [Internet] [Doctoral dissertation]. Loughborough University; 2015. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2134/16587.

Council of Science Editors:

Jinuntuya F. Numerical investigation of the structure effects on water transportation in PEMFC gas diffusion layers using X-ray tomography based Lattice Boltzmann method. [Doctoral Dissertation]. Loughborough University; 2015. Available from: http://hdl.handle.net/2134/16587

14. Santos, Melissa Cruz. Liquid Water Transport in Polymeric Films and Membranes.

Degree: PhD, Chemical Engineering, 2017, Texas A&M University

URL: http://hdl.handle.net/1969.1/161359

► Accurately measuring and understanding transport mechanisms of liquids in polymers is important for the development of materials used in applications such as packaging, water purification,… (more)

Subjects/Keywords: liquid diffusion; polymers; transport

10 more images…

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APA (6^th Edition):

Santos, M. C. (2017). Liquid Water Transport in Polymeric Films and Membranes. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/161359

Chicago Manual of Style (16^th Edition):

Santos, Melissa Cruz. “Liquid Water Transport in Polymeric Films and Membranes.” 2017. Doctoral Dissertation, Texas A&M University. Accessed April 11, 2021. http://hdl.handle.net/1969.1/161359.

MLA Handbook (7^th Edition):

Santos, Melissa Cruz. “Liquid Water Transport in Polymeric Films and Membranes.” 2017. Web. 11 Apr 2021.

Vancouver:

Santos MC. Liquid Water Transport in Polymeric Films and Membranes. [Internet] [Doctoral dissertation]. Texas A&M University; 2017. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1969.1/161359.

Council of Science Editors:

Santos MC. Liquid Water Transport in Polymeric Films and Membranes. [Doctoral Dissertation]. Texas A&M University; 2017. Available from: http://hdl.handle.net/1969.1/161359

Texas A&M University

15. Kumar, Akansha. Measure of Diffusion Model Error for Thermal Radiation Transport.

Degree: MS, Nuclear Engineering, 2013, Texas A&M University

URL: http://hdl.handle.net/1969.1/149531

► The diffusion approximation to the equation of transfer (Boltzmann transport equation) is usually applied to media where scattering dominates the interactions. Diffusion approximation helps in… (more)

▼ The diffusion approximation to the equation of transfer (Boltzmann transport equation) is usually applied to media where scattering dominates the interactions. Diffusion approximation helps in significant savings in terms of code complexity and computational time. However, this approximation often has significant error. Error due to the inherent nature of a physics model is called model error. Information about the model error associated with the diffusion approximation is clearly desirable. An indirect measure of model error is a quantity that is related in some way to the error but not equal to the error. In general, indirect measures of error are expected to be less costly than direct measures. Perhaps the most well-known indirect measure of the diffusion model error is the variable-Eddington tensor. This tensor provides a great deal of information about the angular dependence of the angular intensity solution, but it is not always simple to interpret. We define a new indirect measure of the diffusion model error called the diffusion model error source (DME source). When this DME source is added to the diffusion equation, the transport solution for the angular-integrated intensity is obtained. In contrast to the variable-Eddington tensor, our DME source is a scalar that is conceptually easy to interpret. In addition to defining the DME source analytically, we show how to generate this source numerically relative to the Sn radiative transfer equations with linear-discontinuous spatial discretization. This numerical source is computationally tested and shown to reproduce the Sn solution for a number of problems. Our radiative transfer model solves a coupled, time dependent, multi-frequency, 1-D slab equation and material heat transfer equation. We then use diffusion approximation to solve the same problem. The difference due to this approximation can be modelled by a “diffusion source”. The diffusion source is defined as an amount of inhomogeneous source that, when added to a diffusion calculation, gives a solution for the angle-integrated intensity that is equal to the transport solution. Advisors/Committee Members: Morel, Jim E (advisor), Ragusa, Jean C (committee member), Adams, Marvin L (committee member), Rauchwerger, Lawrence (committee member).

Subjects/Keywords: diffusion; transport; model error

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APA (6^th Edition):

Kumar, A. (2013). Measure of Diffusion Model Error for Thermal Radiation Transport. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/149531

Chicago Manual of Style (16^th Edition):

Kumar, Akansha. “Measure of Diffusion Model Error for Thermal Radiation Transport.” 2013. Masters Thesis, Texas A&M University. Accessed April 11, 2021. http://hdl.handle.net/1969.1/149531.

MLA Handbook (7^th Edition):

Kumar, Akansha. “Measure of Diffusion Model Error for Thermal Radiation Transport.” 2013. Web. 11 Apr 2021.

Vancouver:

Kumar A. Measure of Diffusion Model Error for Thermal Radiation Transport. [Internet] [Masters thesis]. Texas A&M University; 2013. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1969.1/149531.

Council of Science Editors:

Kumar A. Measure of Diffusion Model Error for Thermal Radiation Transport. [Masters Thesis]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/149531

16. Sacchetti, Marcus. Heat and Mass Transfer Studies: Sulfur Diffusion in Polyurethane, Polyphenylquinoxaline as a Heat Exchanger Coating and Polypropylene Membrane Contactor for Deaeration of Cyanide Solution.

Degree: 2015, University of Nevada – Reno

URL: http://hdl.handle.net/11714/2621

► This research studied the heat and mass transfer characteristics of several polymers as applied to different applications. Polyurethane was investigated to determine the mass transport… (more)

Subjects/Keywords: Cyanide; Deaeration; Diffusion; Polyphenylquinoxaline; Transport

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APA (6^th Edition):

Sacchetti, M. (2015). Heat and Mass Transfer Studies: Sulfur Diffusion in Polyurethane, Polyphenylquinoxaline as a Heat Exchanger Coating and Polypropylene Membrane Contactor for Deaeration of Cyanide Solution. (Thesis). University of Nevada – Reno. Retrieved from http://hdl.handle.net/11714/2621

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Sacchetti, Marcus. “Heat and Mass Transfer Studies: Sulfur Diffusion in Polyurethane, Polyphenylquinoxaline as a Heat Exchanger Coating and Polypropylene Membrane Contactor for Deaeration of Cyanide Solution.” 2015. Thesis, University of Nevada – Reno. Accessed April 11, 2021. http://hdl.handle.net/11714/2621.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Sacchetti, Marcus. “Heat and Mass Transfer Studies: Sulfur Diffusion in Polyurethane, Polyphenylquinoxaline as a Heat Exchanger Coating and Polypropylene Membrane Contactor for Deaeration of Cyanide Solution.” 2015. Web. 11 Apr 2021.

Vancouver:

Sacchetti M. Heat and Mass Transfer Studies: Sulfur Diffusion in Polyurethane, Polyphenylquinoxaline as a Heat Exchanger Coating and Polypropylene Membrane Contactor for Deaeration of Cyanide Solution. [Internet] [Thesis]. University of Nevada – Reno; 2015. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/11714/2621.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Sacchetti M. Heat and Mass Transfer Studies: Sulfur Diffusion in Polyurethane, Polyphenylquinoxaline as a Heat Exchanger Coating and Polypropylene Membrane Contactor for Deaeration of Cyanide Solution. [Thesis]. University of Nevada – Reno; 2015. Available from: http://hdl.handle.net/11714/2621

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Cambridge

17. Bell, James. Simulation of diffusion limited aggregation models and related results.

Degree: PhD, 2019, University of Cambridge

URL: https://doi.org/10.17863/CAM.53214 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810046

► This thesis is in three parts. All parts are motivated by a desire to gain a better understanding of models of the phenomenon of two-dimensional… (more)

Subjects/Keywords: Diffusion Limited Aggregation; Stochastic Flows; Time Reversal; Computational Physics; Weak Convergence

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APA (6^th Edition):

Bell, J. (2019). Simulation of diffusion limited aggregation models and related results. (Doctoral Dissertation). University of Cambridge. Retrieved from https://doi.org/10.17863/CAM.53214 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810046

Chicago Manual of Style (16^th Edition):

Bell, James. “Simulation of diffusion limited aggregation models and related results.” 2019. Doctoral Dissertation, University of Cambridge. Accessed April 11, 2021. https://doi.org/10.17863/CAM.53214 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810046.

MLA Handbook (7^th Edition):

Bell, James. “Simulation of diffusion limited aggregation models and related results.” 2019. Web. 11 Apr 2021.

Vancouver:

Bell J. Simulation of diffusion limited aggregation models and related results. [Internet] [Doctoral dissertation]. University of Cambridge; 2019. [cited 2021 Apr 11]. Available from: https://doi.org/10.17863/CAM.53214 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810046.

Council of Science Editors:

Bell J. Simulation of diffusion limited aggregation models and related results. [Doctoral Dissertation]. University of Cambridge; 2019. Available from: https://doi.org/10.17863/CAM.53214 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.810046

Texas A&M University

18. Ye, Jiayan. Statistical Physics Models Governed by Diffusion.

Degree: PhD, Mathematics, 2020, Texas A&M University

URL: http://hdl.handle.net/1969.1/192359

► In this article we consider two probability models: stationary diffusion limited aggregation (SDLA) and finitary random interlacements (FRI). SDLA is a stochastic process on the… (more)

Subjects/Keywords: Probability theory; random walks; stationary diffusion limited aggregation; finitary random interlacements

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APA (6^th Edition):

Ye, J. (2020). Statistical Physics Models Governed by Diffusion. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/192359

Chicago Manual of Style (16^th Edition):

Ye, Jiayan. “Statistical Physics Models Governed by Diffusion.” 2020. Doctoral Dissertation, Texas A&M University. Accessed April 11, 2021. http://hdl.handle.net/1969.1/192359.

MLA Handbook (7^th Edition):

Ye, Jiayan. “Statistical Physics Models Governed by Diffusion.” 2020. Web. 11 Apr 2021.

Vancouver:

Ye J. Statistical Physics Models Governed by Diffusion. [Internet] [Doctoral dissertation]. Texas A&M University; 2020. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/1969.1/192359.

Council of Science Editors:

Ye J. Statistical Physics Models Governed by Diffusion. [Doctoral Dissertation]. Texas A&M University; 2020. Available from: http://hdl.handle.net/1969.1/192359

University of Cambridge

19. Bell, James. Simulation of Diffusion Limited Aggregation Models and Related Results.

Degree: PhD, 2019, University of Cambridge

URL: https://www.repository.cam.ac.uk/handle/1810/306135

► This thesis is in three parts. All parts are motivated by a desire to gain a better understanding of models of the phenomenon of two-dimensional… (more)

Subjects/Keywords: Diffusion Limited Aggregation; Stochastic Flows; Time Reversal; Computational Physics; Weak Convergence

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bell, J. (2019). Simulation of Diffusion Limited Aggregation Models and Related Results. (Doctoral Dissertation). University of Cambridge. Retrieved from https://www.repository.cam.ac.uk/handle/1810/306135

Chicago Manual of Style (16^th Edition):

Bell, James. “Simulation of Diffusion Limited Aggregation Models and Related Results.” 2019. Doctoral Dissertation, University of Cambridge. Accessed April 11, 2021. https://www.repository.cam.ac.uk/handle/1810/306135.

MLA Handbook (7^th Edition):

Bell, James. “Simulation of Diffusion Limited Aggregation Models and Related Results.” 2019. Web. 11 Apr 2021.

Vancouver:

Bell J. Simulation of Diffusion Limited Aggregation Models and Related Results. [Internet] [Doctoral dissertation]. University of Cambridge; 2019. [cited 2021 Apr 11]. Available from: https://www.repository.cam.ac.uk/handle/1810/306135.

Council of Science Editors:

Bell J. Simulation of Diffusion Limited Aggregation Models and Related Results. [Doctoral Dissertation]. University of Cambridge; 2019. Available from: https://www.repository.cam.ac.uk/handle/1810/306135

University of Michigan

20. Hwang, Gi Suk. Pore-Water and Proton Transport in Polymer Electrolyte Membrane Fuel Cell: Molecular Dynamics and Mono- and Bimodal Wetting Treatments of Mesopore Hydrated Nafion.

Degree: PhD, Mechanical Engineering, 2010, University of Michigan

URL: http://hdl.handle.net/2027.42/78840

► Water states and water/proton transport in nanopores of hydrated Nafion, a chosen electrolyte in polymer electrolyte membrane fuel cell, are explained using molecular dynamics (MD)… (more)

▼ Water states and water/proton transport in nanopores of hydrated Nafion, a chosen electrolyte in polymer electrolyte membrane fuel cell, are explained using molecular dynamics (MD) aided bimodal pore-size/water-wetting model. The bimodal model is developed based on the effective Debye screening length for pore water confined by heterogeneously ionized surface, and using small-angle X-ray scattering (SAXS) measurements and existing pore-size distribution. The smaller pores (1 nm) critically confine water and promote capillary condensation (hydrophilic-like), while hindering transport. The larger pores (4 nm) delay the condensation (hydrophobic-like), while allowing bulk-like transport. In a pore network, the small pores selectively wet, while the large pores provide dominant adsorption and transport channels, a novel attribute of the bimodal model. Also, in contrast to the existing Nafion backbone-hydration model, a hydration-dependent, temperature-dependent sulfonic acid surface density is proposed. The bimodal model succeeds in predicting the pore-water states and the transition in adsorption with capillary condensation in the large pores and negligible contribution from the small pores. These are in agreement with experiments. This transition also results in the proton conductivity jump by allowing dominant proton hopping through the larger pores in the network. The bimodal wetting describes the capillary water flow, where the small hydrophilic-like pores provide dominant flow channels, whereas water in the large pores remains immobile due to adsorption only. This water flow network results in lower liquid saturation distribution, in general agreement with the limited experimental results. At elevated temperatures, it is suggested that the sulfonic acid surface site density reduces due to pore surface stretching (relaxing backbone), resulting in hydrophobicity, most pronounced in the large pores. This delays the capillary condensation and decreases adsorption, and masks the transition in proton conductivity. The pore-water state/content for optimal cell operation is also discussed. Advisors/Committee Members: Kaviany, Massoud (committee member), Lastoskie, Christian M. (committee member), Matzger, Adam J. (committee member), Thompson Jr, Levi T. (committee member).

Subjects/Keywords: Pore Water; Molecular Dynamics; Adsorption; Proton Transport; Nafion; Water Diffusion; Mechanical Engineering; Engineering

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hwang, G. S. (2010). Pore-Water and Proton Transport in Polymer Electrolyte Membrane Fuel Cell: Molecular Dynamics and Mono- and Bimodal Wetting Treatments of Mesopore Hydrated Nafion. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/78840

Chicago Manual of Style (16^th Edition):

Hwang, Gi Suk. “Pore-Water and Proton Transport in Polymer Electrolyte Membrane Fuel Cell: Molecular Dynamics and Mono- and Bimodal Wetting Treatments of Mesopore Hydrated Nafion.” 2010. Doctoral Dissertation, University of Michigan. Accessed April 11, 2021. http://hdl.handle.net/2027.42/78840.

MLA Handbook (7^th Edition):

Hwang, Gi Suk. “Pore-Water and Proton Transport in Polymer Electrolyte Membrane Fuel Cell: Molecular Dynamics and Mono- and Bimodal Wetting Treatments of Mesopore Hydrated Nafion.” 2010. Web. 11 Apr 2021.

Vancouver:

Hwang GS. Pore-Water and Proton Transport in Polymer Electrolyte Membrane Fuel Cell: Molecular Dynamics and Mono- and Bimodal Wetting Treatments of Mesopore Hydrated Nafion. [Internet] [Doctoral dissertation]. University of Michigan; 2010. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2027.42/78840.

Council of Science Editors:

Hwang GS. Pore-Water and Proton Transport in Polymer Electrolyte Membrane Fuel Cell: Molecular Dynamics and Mono- and Bimodal Wetting Treatments of Mesopore Hydrated Nafion. [Doctoral Dissertation]. University of Michigan; 2010. Available from: http://hdl.handle.net/2027.42/78840

University of California – Irvine

21. Lu, Michael D. Effect of Water Vapor on Grain-Boundary Diffusion of Oxygen in Ceramic Processing.

Degree: Materials Science and Engineering, 2016, University of California – Irvine

URL: http://www.escholarship.org/uc/item/9sf9w4zp

► The results of prior experiments have suggested faster diffusion of oxygen in polycrystalline alumina when exposed to water vapor. It is hypothesized that the dissociation… (more)

Subjects/Keywords: Materials Science; Ceramics; Diffusion; Water

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APA (6^th Edition):

Lu, M. D. (2016). Effect of Water Vapor on Grain-Boundary Diffusion of Oxygen in Ceramic Processing. (Thesis). University of California – Irvine. Retrieved from http://www.escholarship.org/uc/item/9sf9w4zp

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Lu, Michael D. “Effect of Water Vapor on Grain-Boundary Diffusion of Oxygen in Ceramic Processing.” 2016. Thesis, University of California – Irvine. Accessed April 11, 2021. http://www.escholarship.org/uc/item/9sf9w4zp.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Lu, Michael D. “Effect of Water Vapor on Grain-Boundary Diffusion of Oxygen in Ceramic Processing.” 2016. Web. 11 Apr 2021.

Vancouver:

Lu MD. Effect of Water Vapor on Grain-Boundary Diffusion of Oxygen in Ceramic Processing. [Internet] [Thesis]. University of California – Irvine; 2016. [cited 2021 Apr 11]. Available from: http://www.escholarship.org/uc/item/9sf9w4zp.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Lu MD. Effect of Water Vapor on Grain-Boundary Diffusion of Oxygen in Ceramic Processing. [Thesis]. University of California – Irvine; 2016. Available from: http://www.escholarship.org/uc/item/9sf9w4zp

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

INP Toulouse

22. El Hannach, Mohamed. Simulation et analyse des mécanismes de transfert diphasique dans les Couches Actives des Piles à Combustible PEMFC : Simulation and analysis of two-phase transport mechanisms inside the Cathode Catalyst Layer of the PEM Fuel Cell.

Degree: Docteur es, Energétique et transferts, 2011, INP Toulouse

URL: http://www.theses.fr/2011INPT0092

►

Afin de pouvoir utiliser les piles à combustible du type PEMFC dans une application automobile, leur coût doit être diminué et leur durée de vie… (more)

▼

Afin de pouvoir utiliser les piles à combustible du type PEMFC dans une application automobile, leur coût doit être diminué et leur durée de vie doit être augmentée. De nombreux résultats montrent que la gestion de l'eau dans les piles PEMFC est essentielle sur ces aspects et qu’une meilleure maitrise contribuera a développer des piles plus performantes. La couche active cathodique (CCL, Cathode Catalyst Layer) est le lieu de production de l'eau ce qui en rend l'optimisation importante pour assurer une bonne gestion de l'eau. Dans ce travail, la méthode réseau de pores a été adaptée pour modéliser le transport diphasique dans la structure poreuse de la CCL. Dans l'état de l'art actuel, le modèle développé est le seul permettant d’analyser l'effet des proprietes locales de la CCL (structure, mouillabilite…) sur les mecanismes de transport diphasique. Cet outil de compréhension constitue également une base pour proposer des améliorations de la CCL afin d'améliorer les performances des piles. Les algorithmes d'invasion développés ont été analysés d'une façon détaillée. Le transport fluidique (gaz et liquide) est couplé avec le transport des charges (électrons et protons) par un modèle de réaction électrochimique. Les mécanismes de capillarité, de diffusion gazeuse et d’evaporation sont integres au modele afin d'avoir une représentation la plus complète possible du fonctionnement de la CCL. La description de la structure poreuse par un réseau de pore régulier, l'algorithme d'invasion de l'eau liquide et le modèle de la diffusion des gaz ont été validés par des comparaisons avec des résultats expérimentaux de la littérature ou spécifiques de ce travail. Le modèle est ensuite exploité pour analyser l'effet des paramètres de la CCL tels que la mouillabilité et la taille des pores sur les performances de la couche active. Les résultats permettent d’analyser de premieres idees de modifications de la CCL pour ameliorer la gestion de l’eau et les performances des PEMFC.

In order to use PEM fuel cells in an automotive application, their cost must be reduced and their lifetime must be increased. Many results show that water management is a critical issue in PEMFC optimization. The water is produced in the cathode active layer (CCL) which makes the optimization of this component very important to ensure a better water management in the PEMFC. In this work, the pore network method has been adapted to model the two-phase transport in the porous structure of the CCL. Considering the state of the art, this is the only model developed to analyze the effect of local properties of the CCL (structure, wetting ...) on the two-phase transport mechanisms. This model is proposed as a scientific tool to help understanding the fundamentals behind the transport phenomena inside the CCL and also to help in the conception of the future CCL. The liquid invasion algorithms developed in this work were analyzed in details. The fluids transport (gas and liquid) is coupled with the charges transport (electrons and protons) using an electrochemical…

Advisors/Committee Members: Prat, Marc (thesis director).

Subjects/Keywords: Transport diphasique; Gestion de l'eau; Diffusion; Réseau de pores; Milieu poreux; Mouillabilité mixte; Couche active; Pemfc; Two-phase transport; Water management; Diffusion; Pore network; Mixed wettabiliy; Porous media; Pemfc; Catalyst layer

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

El Hannach, M. (2011). Simulation et analyse des mécanismes de transfert diphasique dans les Couches Actives des Piles à Combustible PEMFC : Simulation and analysis of two-phase transport mechanisms inside the Cathode Catalyst Layer of the PEM Fuel Cell. (Doctoral Dissertation). INP Toulouse. Retrieved from http://www.theses.fr/2011INPT0092

Chicago Manual of Style (16^th Edition):

El Hannach, Mohamed. “Simulation et analyse des mécanismes de transfert diphasique dans les Couches Actives des Piles à Combustible PEMFC : Simulation and analysis of two-phase transport mechanisms inside the Cathode Catalyst Layer of the PEM Fuel Cell.” 2011. Doctoral Dissertation, INP Toulouse. Accessed April 11, 2021. http://www.theses.fr/2011INPT0092.

MLA Handbook (7^th Edition):

El Hannach, Mohamed. “Simulation et analyse des mécanismes de transfert diphasique dans les Couches Actives des Piles à Combustible PEMFC : Simulation and analysis of two-phase transport mechanisms inside the Cathode Catalyst Layer of the PEM Fuel Cell.” 2011. Web. 11 Apr 2021.

Vancouver:

El Hannach M. Simulation et analyse des mécanismes de transfert diphasique dans les Couches Actives des Piles à Combustible PEMFC : Simulation and analysis of two-phase transport mechanisms inside the Cathode Catalyst Layer of the PEM Fuel Cell. [Internet] [Doctoral dissertation]. INP Toulouse; 2011. [cited 2021 Apr 11]. Available from: http://www.theses.fr/2011INPT0092.

Council of Science Editors:

El Hannach M. Simulation et analyse des mécanismes de transfert diphasique dans les Couches Actives des Piles à Combustible PEMFC : Simulation and analysis of two-phase transport mechanisms inside the Cathode Catalyst Layer of the PEM Fuel Cell. [Doctoral Dissertation]. INP Toulouse; 2011. Available from: http://www.theses.fr/2011INPT0092

University of Illinois – Urbana-Champaign

23. Bizjack, Matthew Thomas. Investigating uranium mobility using groundwater 238U/235U data and a reactive transport model.

Degree: MS, Geology, 2016, University of Illinois – Urbana-Champaign

URL: http://hdl.handle.net/2142/90833

► In order to better understand chemical reactions affecting the subsurface transport of the widespread contaminant uranium (U), we present a numerical reactive transport model which… (more)

▼ In order to better understand chemical reactions affecting the subsurface transport of the widespread contaminant uranium (U), we present a numerical reactive transport model which explicitly incorporates variations in the 238U/235U isotope ratio. Bioremediation, the microbial reductive immobilization of aqueous U(VI) to solid U(IV), has been proposed as a U remediation technique. Both laboratory and field experiments have demonstrated that microbial reduction of U(VI) alters 238U/235U, producing a 238U-enriched solid U(IV) product. Other major U reactive transport processes do not fractionate isotopes significantly. This suggests the potential to quantify the extent of bioreduction occurring in groundwater containing U using 238U/235U as a compliment to the information gained through U concentration measurements. A recent study of a U bioremediation experiment at a contaminated DOE site in Rifle, Colorado, applied Rayleigh distillation models to quantify U stable isotope fractionation observed during biostimulation via acetate amendment. These simplified models have known inaccuracies and do not incorporate the complex hydrologic and geochemical aspects of the site. To more accurately interpret these measured U isotope ratios, we present a multi-component reactive transport model capable of reproducing observed trends in geochemistry and 238U/235U ratios from the field experiment. Model results suggest that the rate-limited transport properties of U in the Rifle aquifer are governed by the presence of low-permeability regions in the modeling domain and that these zones are responsible for the suggested "memory" effect observed in previous U isotope studies at this site. Accurate modeling of observed U isotope ratios is crucial to their use as a method of tracking bioremediation, and this study serves to advance the quantitative application of isotope systems in reactive transport. Advisors/Committee Members: Johnson, Thomas M (advisor), Druhan, Jennifer L (advisor).

Subjects/Keywords: uranium; bioremediation; reactive transport; stable isotopes; CrunchTope; rate-limited desorption

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Bizjack, M. T. (2016). Investigating uranium mobility using groundwater 238U/235U data and a reactive transport model. (Thesis). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/90833

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Bizjack, Matthew Thomas. “Investigating uranium mobility using groundwater 238U/235U data and a reactive transport model.” 2016. Thesis, University of Illinois – Urbana-Champaign. Accessed April 11, 2021. http://hdl.handle.net/2142/90833.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Bizjack, Matthew Thomas. “Investigating uranium mobility using groundwater 238U/235U data and a reactive transport model.” 2016. Web. 11 Apr 2021.

Vancouver:

Bizjack MT. Investigating uranium mobility using groundwater 238U/235U data and a reactive transport model. [Internet] [Thesis]. University of Illinois – Urbana-Champaign; 2016. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/2142/90833.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Bizjack MT. Investigating uranium mobility using groundwater 238U/235U data and a reactive transport model. [Thesis]. University of Illinois – Urbana-Champaign; 2016. Available from: http://hdl.handle.net/2142/90833

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

24. Cantin, Pierre. Approximation of scalar and vector transport problems on polyhedral meshes : Approximation des problèmes de transport scalaire et vectoriel sur maillages polyédriques.

Degree: Docteur es, Mathématiques, 2016, Université Paris-Est

URL: http://www.theses.fr/2016PESC1028

►

Cette thèse étudie, au niveau continu et au niveau discret sur des maillages polyédriques, les équations de transport tridimensionnelles scalaire et vectorielle. Ces équations sont… (more)

▼

Cette thèse étudie, au niveau continu et au niveau discret sur des maillages polyédriques, les équations de transport tridimensionnelles scalaire et vectorielle. Ces équations sont constituées d'un terme diffusif, d'un terme advectif et d'un terme réactif. Dans le cadre des systèmes de Friedrichs, l'analyse mathématique est effectuée dans les espaces du graphe associés aux espaces de Lebesgue. Les conditions de positivité usuelles sur le tenseur de Friedrichs sont étendues au niveau continu et au niveau discret afin de prendre en compte les cas d'intérêt pratique où ce tenseur prend des valeurs nulles ou raisonnablement négatives. Un nouveau schéma convergeant à l'ordre 3/2 est proposé pour le problème d'advection-réaction scalaire en considérant des degrés de liberté scalaires associés aux sommets du maillage. Deux nouveaux schémas considérant également des degrés de libertés aux sommets sont proposés pour le problème de transport scalaire en traitant de manière robuste les différents régimes dominants. Le premier schéma converge à l'ordre 1/2 si les effets advectifs sont dominants et à l'ordre 1 si les effets diffusifs sont dominants. Le second schéma améliore la précision de ce schéma en convergeant à l'ordre 3/2 lorsque les effets advectifs sont dominants. Enfin, un nouveau schéma convergeant à l'ordre 1/2 est obtenu pour le problème d'advection-réaction vectoriel en considérant un seul et unique degré de liberté scalaire sur chaque arête du maillage. La précision et les performances de tous ces schémas sont examinées sur plusieurs cas tests utilisant des maillages polyédriques tridimensionnels

This thesis analyzes, at the continuous and at the discrete level on polyhedral meshes, the scalar and the vector transport problems in three-dimensional domains. These problems are composed of a diffusive term, an advective term, and a reactive term. In the context of Friedrichs systems, the continuous problems are analyzed in Lebesgue graph spaces. The classical positivity assumption on the Friedrichs tensor is generalized so as to consider the case of practical interest where this tensor takes null or slightly negative values. A new scheme converging at the order 3/2 is devised for the scalar advection-reaction problem using scalar degrees of freedom attached to mesh vertices. Two new schemes considering as well scalar degrees of freedom attached to mesh vertices are devised for the scalar transport problem and are robust with respect to the dominant regime. The first scheme converges at the order 1/2 when advection effects are dominant and at the order 1 when diffusion effects are dominant. The second scheme improves the accuracy by converging at the order 3/2 when advection effects are dominant. Finally, a new scheme converging at the order 1/2 is devised for the vector advection-reaction problem considering only one scalar degree of freedom per mesh edge. The accuracy and the efficiency of all these schemes are assessed on various test cases using three-dimensional polyhedral meshes

Advisors/Committee Members: Ern, Alexandre (thesis director).

Subjects/Keywords: Maillages polyédriques; Systèmes de Friedrichs; Advection; Diffusion; Transport scalaire; Transport vectoriel; Polyhedral meshes; Friedrichs systems; Advection; Diffusion; Scalar transport; Vector transport

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Cantin, P. (2016). Approximation of scalar and vector transport problems on polyhedral meshes : Approximation des problèmes de transport scalaire et vectoriel sur maillages polyédriques. (Doctoral Dissertation). Université Paris-Est. Retrieved from http://www.theses.fr/2016PESC1028

Chicago Manual of Style (16^th Edition):

Cantin, Pierre. “Approximation of scalar and vector transport problems on polyhedral meshes : Approximation des problèmes de transport scalaire et vectoriel sur maillages polyédriques.” 2016. Doctoral Dissertation, Université Paris-Est. Accessed April 11, 2021. http://www.theses.fr/2016PESC1028.

MLA Handbook (7^th Edition):

Cantin, Pierre. “Approximation of scalar and vector transport problems on polyhedral meshes : Approximation des problèmes de transport scalaire et vectoriel sur maillages polyédriques.” 2016. Web. 11 Apr 2021.

Vancouver:

Cantin P. Approximation of scalar and vector transport problems on polyhedral meshes : Approximation des problèmes de transport scalaire et vectoriel sur maillages polyédriques. [Internet] [Doctoral dissertation]. Université Paris-Est; 2016. [cited 2021 Apr 11]. Available from: http://www.theses.fr/2016PESC1028.

Council of Science Editors:

Cantin P. Approximation of scalar and vector transport problems on polyhedral meshes : Approximation des problèmes de transport scalaire et vectoriel sur maillages polyédriques. [Doctoral Dissertation]. Université Paris-Est; 2016. Available from: http://www.theses.fr/2016PESC1028

University of New Mexico

25. Rezaei Talarposhti, Morteza. Microbial desalination cells with efficient platinum group metal-free cathode catalysts.

Degree: Chemical and Biological Engineering, 2017, University of New Mexico

URL: https://digitalrepository.unm.edu/cbe_etds/70

► Iron-nitrogen-carbon based catalyst was used at the cathode of a microbial desalination cell (MDC) and compared with platinum (Pt) and activated carbon (AC) cathode.… (more)

Subjects/Keywords: Microbial desalination cell; electro dialysis; Power density; Waste water treatment; Bio-energy production; Reverse Osmosis; Diffusion; Catalysis and Reaction Engineering; Chemical Engineering; Membrane Science; Transport Phenomena

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Rezaei Talarposhti, M. (2017). Microbial desalination cells with efficient platinum group metal-free cathode catalysts. (Masters Thesis). University of New Mexico. Retrieved from https://digitalrepository.unm.edu/cbe_etds/70

Chicago Manual of Style (16^th Edition):

Rezaei Talarposhti, Morteza. “Microbial desalination cells with efficient platinum group metal-free cathode catalysts.” 2017. Masters Thesis, University of New Mexico. Accessed April 11, 2021. https://digitalrepository.unm.edu/cbe_etds/70.

MLA Handbook (7^th Edition):

Rezaei Talarposhti, Morteza. “Microbial desalination cells with efficient platinum group metal-free cathode catalysts.” 2017. Web. 11 Apr 2021.

Vancouver:

Rezaei Talarposhti M. Microbial desalination cells with efficient platinum group metal-free cathode catalysts. [Internet] [Masters thesis]. University of New Mexico; 2017. [cited 2021 Apr 11]. Available from: https://digitalrepository.unm.edu/cbe_etds/70.

Council of Science Editors:

Rezaei Talarposhti M. Microbial desalination cells with efficient platinum group metal-free cathode catalysts. [Masters Thesis]. University of New Mexico; 2017. Available from: https://digitalrepository.unm.edu/cbe_etds/70

University of South Florida

26. Dooris, Matthew David. Apparent Total Evaporative Resistance Values From Human Trials Over a Range of Metabolic and Heat Stress Levels.

Degree: 2011, University of South Florida

URL: https://scholarcommons.usf.edu/etd/3078

► Failure to maintain thermal equilibrium can cause uncontrollable increases in body core temperature beyond critical upper limits. In selecting clothing, consideration must be given to… (more)

Subjects/Keywords: Convective Transport; Evaporative Cooling; Heat Exchange; Protective Clothing; Water Vapor Diffusion; American Studies; Arts and Humanities; Environmental Health and Protection; Industrial Engineering; Occupational Health and Industrial Hygiene

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Dooris, M. D. (2011). Apparent Total Evaporative Resistance Values From Human Trials Over a Range of Metabolic and Heat Stress Levels. (Thesis). University of South Florida. Retrieved from https://scholarcommons.usf.edu/etd/3078

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Dooris, Matthew David. “Apparent Total Evaporative Resistance Values From Human Trials Over a Range of Metabolic and Heat Stress Levels.” 2011. Thesis, University of South Florida. Accessed April 11, 2021. https://scholarcommons.usf.edu/etd/3078.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Dooris, Matthew David. “Apparent Total Evaporative Resistance Values From Human Trials Over a Range of Metabolic and Heat Stress Levels.” 2011. Web. 11 Apr 2021.

Vancouver:

Dooris MD. Apparent Total Evaporative Resistance Values From Human Trials Over a Range of Metabolic and Heat Stress Levels. [Internet] [Thesis]. University of South Florida; 2011. [cited 2021 Apr 11]. Available from: https://scholarcommons.usf.edu/etd/3078.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Dooris MD. Apparent Total Evaporative Resistance Values From Human Trials Over a Range of Metabolic and Heat Stress Levels. [Thesis]. University of South Florida; 2011. Available from: https://scholarcommons.usf.edu/etd/3078

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

27. Beacon, Daniel Richard. Next Generation Reactor Core Analysis Using Iterative Transport-diffusion Methodology.

Degree: 2014, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/22462

► This thesis details the efforts, changes, and improvements that have been made to the Next Generation Method (NGM) Iterative Transport-Diffusion Methodology (ITDM), a long term… (more)

Subjects/Keywords: Iterative; Transport; Diffusion; ITDM; Reactor Analysis

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APA (6^th Edition):

Beacon, D. R. (2014). Next Generation Reactor Core Analysis Using Iterative Transport-diffusion Methodology. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/22462

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Beacon, Daniel Richard. “Next Generation Reactor Core Analysis Using Iterative Transport-diffusion Methodology.” 2014. Thesis, Penn State University. Accessed April 11, 2021. https://submit-etda.libraries.psu.edu/catalog/22462.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Beacon, Daniel Richard. “Next Generation Reactor Core Analysis Using Iterative Transport-diffusion Methodology.” 2014. Web. 11 Apr 2021.

Vancouver:

Beacon DR. Next Generation Reactor Core Analysis Using Iterative Transport-diffusion Methodology. [Internet] [Thesis]. Penn State University; 2014. [cited 2021 Apr 11]. Available from: https://submit-etda.libraries.psu.edu/catalog/22462.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Beacon DR. Next Generation Reactor Core Analysis Using Iterative Transport-diffusion Methodology. [Thesis]. Penn State University; 2014. Available from: https://submit-etda.libraries.psu.edu/catalog/22462

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Houston

28. He, Kai 1985-. Understanding the Transport of Nanoparticles in Microchannel based Model Porous Media.

Degree: PhD, Chemical Engineering, 2013, University of Houston

URL: http://hdl.handle.net/10657/3284

► Recently, nanoparticle dispersions have been explored to improve the exploration and production of sub-surface hydrocarbons. To address that effort it is critical to fundamentally understand… (more)

▼ Recently, nanoparticle dispersions have been explored to improve the exploration and production of sub-surface hydrocarbons. To address that effort it is critical to fundamentally understand the dynamics and transport of nanoparticles in porous media. Natural porous media are heterogeneous in confinement, connectivity and surface chemistry resulting in different physical mechanisms for transport. Thus, understanding the dynamics and transport of nanoparticles in model porous media is important. In this work, an effective methodology for improved understanding of diffusion and transport mechanisms of nanoparticles in model porous media has been developed, using a combination of nanofabrication and optical microscopy based techniques - differential dynamics microscopy (DDM) and single particle tracking (SPT). First, the diffusive dynamics of 100 nm to 400 nm diameter polystyrene nanoparticles dispersed in water were examined using DDM. The diffusion coefficients measured by DDM were in excellent agreement with those measured by dynamic light scattering, indicating that DDM is a valid tool to investigate the dynamics of nanoparticles. Next, the confinement effect on the diffusive dynamics of nanoparticles was investigated using DDM and SPT. Arrays of nanoposts of diameter 500 nm and spacing ranging from 0.4 to 10 m were fabricated to confine 200-400 nm diameter nanoparticles. Two effects of confinement imposed by the cylindrical posts were found: slowing diffusive dynamics of nanoparticles and inducing emergence of multiple relaxation times and further modifying the relaxation process. Results also showed that under modest confinement nanoparticles remained diffusive; while under extreme confinement diffusion became anomalous. Finally, transport of nanoparticles through model porous media was probed using SPT. Microchannels with cylindrical post arrays of post spacing ranging from 0.8 to 2 m were fabricated, nanoparticles were then injected into the microchannel with Re <0.004 and Pex ranging from 2.2 to 58.9. Results suggest that shapes of nanoparticle trajectories are strongly dependent on the Pex. It was also found that confinement not only slowed the diffusive dynamics but also the convective flow. Importantly, a geometrical dependence of the ratio of longitudinal dispersion DL to transverse dispersion Dm was found, which provide a first microscopic view of the transport of nanoparticles in complex geometries. Advisors/Committee Members: Krishnamoorti, Ramanan (advisor), Balakotaiah, Vemuri (committee member), Conrad, Jacinta C. (committee member), Sharma, Pradeep (committee member), Vipulanandan, Cumaraswamy (committee member).

Subjects/Keywords: Nanoparticles; Diffusion; Transport; Nanofabrication; Model porous media

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

He, K. 1. (2013). Understanding the Transport of Nanoparticles in Microchannel based Model Porous Media. (Doctoral Dissertation). University of Houston. Retrieved from http://hdl.handle.net/10657/3284

Chicago Manual of Style (16^th Edition):

He, Kai 1985-. “Understanding the Transport of Nanoparticles in Microchannel based Model Porous Media.” 2013. Doctoral Dissertation, University of Houston. Accessed April 11, 2021. http://hdl.handle.net/10657/3284.

MLA Handbook (7^th Edition):

He, Kai 1985-. “Understanding the Transport of Nanoparticles in Microchannel based Model Porous Media.” 2013. Web. 11 Apr 2021.

Vancouver:

He K1. Understanding the Transport of Nanoparticles in Microchannel based Model Porous Media. [Internet] [Doctoral dissertation]. University of Houston; 2013. [cited 2021 Apr 11]. Available from: http://hdl.handle.net/10657/3284.

Council of Science Editors:

He K1. Understanding the Transport of Nanoparticles in Microchannel based Model Porous Media. [Doctoral Dissertation]. University of Houston; 2013. Available from: http://hdl.handle.net/10657/3284

University of Oxford

29. Heaton, Luke Latham Moorhouse. Biological transport networks.

Degree: PhD, 2012, University of Oxford

URL: https://ora.ox.ac.uk/objects/uuid:48cf4d64-c051-463c-b9f8-ff50f1a4c2c7 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.711636

► Cord-forming fungi form extensive networks that continuously adapt to maintain an efficient transport system, and we can photograph their growth, digitize the network structure, and… (more)

▼ Cord-forming fungi form extensive networks that continuously adapt to maintain an efficient transport system, and we can photograph their growth, digitize the network structure, and measure the movement of radio-tracers. Mycelial networks are more accessible than the transport networks of other multicellular organisms, but there are many open questions concerning the coordination of growth and transport within fungal networks. As osmotically driven water uptake is often distal from the growing margin, and aqueous fluids are effectively incompressible, we propose that growth induces mass flows across the mycelium, towards the growing regions. We imaged the temporal evolution of networks formed by Phanerochaete velutina, and at each stage calculated the unique set of currents that account for the observed changes in cord volume, while minimizing the work required to overcome viscous drag. Predicted speeds were in reasonable agreement with experimental data, and cords that were predicted to carry large currents were significantly more likely to increase in size than cords with small currents. We have also developed an efficient method for calculating the exact quantity of resource in each part of an arbitrary network, where the resource is lost or delivered out of the network at a given rate, while being subject to advection and diffusion. This method enabled us to model the spatial distribution of resource that emerges as a fungal network grows over time, and we found good empirical agreement between our model and experimental data gathered using radio-labelled tracers. Our results suggest that in well insulated fungal networks, growth-induced mass flow is sufficient to account for long distance transport. We conclude that active transport mechanisms may only be required at the very end of the transport pathway, near the growing tips. We also developed a simple model of glucose delivery through vascular networks, which indicates that increasing the number of blood vessels in a region can actually decrease the total rate of glucose delivery.

Subjects/Keywords: 579.5; Biology; Fungi; advection-diffusion; transport networks

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Heaton, L. L. M. (2012). Biological transport networks. (Doctoral Dissertation). University of Oxford. Retrieved from https://ora.ox.ac.uk/objects/uuid:48cf4d64-c051-463c-b9f8-ff50f1a4c2c7 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.711636

Chicago Manual of Style (16^th Edition):

Heaton, Luke Latham Moorhouse. “Biological transport networks.” 2012. Doctoral Dissertation, University of Oxford. Accessed April 11, 2021. https://ora.ox.ac.uk/objects/uuid:48cf4d64-c051-463c-b9f8-ff50f1a4c2c7 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.711636.

MLA Handbook (7^th Edition):

Heaton, Luke Latham Moorhouse. “Biological transport networks.” 2012. Web. 11 Apr 2021.

Vancouver:

Heaton LLM. Biological transport networks. [Internet] [Doctoral dissertation]. University of Oxford; 2012. [cited 2021 Apr 11]. Available from: https://ora.ox.ac.uk/objects/uuid:48cf4d64-c051-463c-b9f8-ff50f1a4c2c7 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.711636.

Council of Science Editors:

Heaton LLM. Biological transport networks. [Doctoral Dissertation]. University of Oxford; 2012. Available from: https://ora.ox.ac.uk/objects/uuid:48cf4d64-c051-463c-b9f8-ff50f1a4c2c7 ; https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.711636

Hong Kong University of Science and Technology

30. Zhang, Yujie. Advanced numerical schemes for transient non-continuum heat conduction and surface diffusion.

Degree: 2015, Hong Kong University of Science and Technology

URL: http://repository.ust.hk/ir/Record/1783.1-78793 ; https://doi.org/10.14711/thesis-b1514572 ; http://repository.ust.hk/ir/bitstream/1783.1-78793/1/th_redirect.html

► In this thesis, some advanced numerical schemes are developed for applications in modeling transient non-continuum heat conduction and surface diffusion motion to improve the accuracy… (more)

▼ In this thesis, some advanced numerical schemes are developed for applications in modeling transient non-continuum heat conduction and surface diffusion motion to improve the accuracy and efficiency. In the first part, a new set of modified ballistic-diffusive equations are proposed for the modeling of transient non-continuum heat conduction. For non-continuum phonon transport, the phonon Boltzmann transport equation is regarded as an accurate model when the wave effect is negligible. However it is difficult and computationally intensive to solve. The ballistic-diffusive approach (BDE) proposed by Chen [G. Chen, phys. Rev. Lett. 86, 2297 (2001)] greatly simplifies the solution procedure and reduces the computational cost by modeling the ballistic and diffusive parts separately and using the first-order spherical harmonic function to approximate the diffusive intensity. The accuracy of the BDE remains to be improved particularly near the boundary and at large time scales. In this part, a deficiency in the BDE is identified, and a new physically sound boundary model is proposed, which leads to a new set of ballistic-diffusive equations. Several benchmark problems are employed to validate the performance of the modified ballistic-diffusive approach, and results indicate the new approach is much more accurate than the original BDE and yet retains the same level of efficiency. Hence it is an effective method for the modeling of transient non-continuum heat conduction. In the second part, a high-order level set method based on the total variation diminishing Runge-Kutta method, a high-order scheme for distance computation and a smoothing scheme are developed for simulating curvature driven flow and surface diffusion motion, which overcomes the high-order CFL time restriction. The enhanced stability is achieved by utilizing several techniques, resulting in an accurate and smooth velocity field. In particular, the scheme for distance computation is used to reinitialize the level-set function and to extend the velocity from the zero level-set to the remaining of the domain. As such, it greatly reduces the accumulated errors typically observed in the traditional PDE-based methods. The smoothing technique is used to remove the high-frequency oscillations procedure by the high-order derivatives of the level-set function and is the key to overcome the CFL restriction on the time step. Results on several benchmark problems have demonstrated that compared with the semi-implicit methods, the developed method is more accurate and achieves the same, if not better, stability. Although the level set method can handle topological changes naturally, its performance in simulating curvature driven flows and surface diffusion motions highly depends on how accurate the interface curvature and intrinsic laplacian of curvature can be simulated, particularly in cases when topological change happens at interfaces that are close by. Based on the high-order accurate approach developed by Saye for computing the minimum distance to implicitly defined…

Subjects/Keywords: Thermal conductivity ; Mathematical models ; Diffusion ; Transport theory

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Zhang, Y. (2015). Advanced numerical schemes for transient non-continuum heat conduction and surface diffusion. (Thesis). Hong Kong University of Science and Technology. Retrieved from http://repository.ust.hk/ir/Record/1783.1-78793 ; https://doi.org/10.14711/thesis-b1514572 ; http://repository.ust.hk/ir/bitstream/1783.1-78793/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Zhang, Yujie. “Advanced numerical schemes for transient non-continuum heat conduction and surface diffusion.” 2015. Thesis, Hong Kong University of Science and Technology. Accessed April 11, 2021. http://repository.ust.hk/ir/Record/1783.1-78793 ; https://doi.org/10.14711/thesis-b1514572 ; http://repository.ust.hk/ir/bitstream/1783.1-78793/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Zhang, Yujie. “Advanced numerical schemes for transient non-continuum heat conduction and surface diffusion.” 2015. Web. 11 Apr 2021.

Vancouver:

Zhang Y. Advanced numerical schemes for transient non-continuum heat conduction and surface diffusion. [Internet] [Thesis]. Hong Kong University of Science and Technology; 2015. [cited 2021 Apr 11]. Available from: http://repository.ust.hk/ir/Record/1783.1-78793 ; https://doi.org/10.14711/thesis-b1514572 ; http://repository.ust.hk/ir/bitstream/1783.1-78793/1/th_redirect.html.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Zhang Y. Advanced numerical schemes for transient non-continuum heat conduction and surface diffusion. [Thesis]. Hong Kong University of Science and Technology; 2015. Available from: http://repository.ust.hk/ir/Record/1783.1-78793 ; https://doi.org/10.14711/thesis-b1514572 ; http://repository.ust.hk/ir/bitstream/1783.1-78793/1/th_redirect.html

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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Open Access Theses and Dissertations