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Статті в журналах з теми "Microfluidic fuell cell"
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Wang, Lingtian, Dajun Jiang, Qiyang Wang, Qing Wang, Haoran Hu, and Weitao Jia. "The Application of Microfluidic Techniques on Tissue Engineering in Orthopaedics." Current Pharmaceutical Design 24, no. 45 (April 16, 2019): 5397–406. http://dx.doi.org/10.2174/1381612825666190301142833.
Повний текст джерелаАнотація:
Background: Tissue engineering (TE) is a promising solution for orthopaedic diseases such as bone or cartilage defects and bone metastasis. Cell culture in vitro and scaffold fabrication are two main parts of TE, but these two methods both have their own limitations. The static cell culture medium is unable to achieve multiple cell incubation or offer an optimal microenvironment for cells, while regularly arranged structures are unavailable in traditional cell-laden scaffolds, which results in low biocompatibility. To solve these problems, microfluidic techniques are combined with TE. By providing 3-D networks and interstitial fluid flows, microfluidic platforms manage to maintain phenotype and viability of osteocytic or chondrocytic cells, and the precise manipulation of liquid, gel and air flows in microfluidic devices leads to the highly organized construction of scaffolds. Methods: In this review, we focus on the recent advances of microfluidic techniques applied in the field of tissue engineering, especially in orthropaedics. An extensive literature search was done using PubMed. The introduction describes the properties of microfluidics and how it exploits the advantages to the full in the aspects of TE. Then we discuss the application of microfluidics on the cultivation of osteocytic cells and chondrocytes, and other extended researches carried out on this platform. The following section focuses on the fabrication of highly organized scaffolds and other biomaterials produced by microfluidic devices. Finally, the incubation and studying of bone metastasis models in microfluidic platforms are discussed. Conclusion: The combination of microfluidics and tissue engineering shows great potentials in the osteocytic cell culture and scaffold fabrication. Though there are several problems that still require further exploration, the future of microfluidics in TE is promising.
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Naher, Sumsun, Dylan Orpen, Dermot Brabazon, and Muhammad M. Morshed. "An Overview of Microfluidic Mixing Application." Advanced Materials Research 83-86 (December 2009): 931–39. http://dx.doi.org/10.4028/www.scientific.net/amr.83-86.931.
Повний текст джерелаАнотація:
Microfluidics is a technology where application span the biomedical field and beyond. Single cell analysis, tissue engineering, capillary electrophoresis, cancer detection, and immunoassays are just some of the applications within the medical field where microfluidics have excelled. The development of microfluidic technology has lead to novel research into fuel cells, ink jet printing, microreactors and electronic component cooling areas as diverse as food, pharmaceutics, cosmetics, medicine and biotechnology have benefited from these developments. Since laminar flow is prevailing at most flow regimes in the micro-scale, thorough mixing is a challenge within microfluidics. Therefore, understanding the flow fields on the micro-scale is key to the development of methods for successfully microfluidic mixing applications.
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Goel, Sanket, Lanka Tata Rao, Prakash Rewatkar, Haroon Khan, Satish Kumar Dubey, Arshad Javed, Gyu Man Kim, and Sanket Goel. "Single microfluidic fuel cell with three fuels – formic acid, glucose and microbes: A comparative performance investigation." Journal of Electrochemical Science and Engineering 11, no. 4 (October 5, 2021): 306–16. http://dx.doi.org/10.5599/jese.1092.
Повний текст джерелаАнотація:
The development of microfluidic and nanofluidic devices is gaining remarkable attention due to the emphasis put on miniaturization of conventional energy conversion and storage processes. A microfluidic fuel cell can integrate flow of electrolytes, electrode-electrolyte interactions, and power generation in a microfluidic channel. Such microfluidic fuel cells can be categorized on the basis of electrolytes and catalysts used for power generation. In this work, for the first time, a single microfluidic fuel cell was harnessed by using different fuels like glucose, microbes and formic acid. Herein, multi-walled carbon nanotubes (MWCNT) acted as electrode material, and performance investigations were carried out separately on the same microfluidic device for three different types of fuel cells (formic acid, microbial and enzymatic). The fabricated miniaturized microfluidic device was successfully used to harvest energy in microwatts from formic acid, microbes and glucose, without any metallic catalyst. The developed microfluidic fuel cells can maintain stable open-circuit voltage, which can be used for energizing various low-power portable devices or applications.
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Goel, Sanket, Lanka Tata Rao, Prakash Rewatkar, Haroon Khan, Satish Kumar Dubey, Arshad Javed, Gyu Man Kim, and Sanket Goel. "Single microfluidic fuel cell with three fuels – formic acid, glucose and microbes: A comparative performance investigation." Journal of Electrochemical Science and Engineering 11, no. 4 (October 5, 2021): 306–16. http://dx.doi.org/10.5599/jese.1092.
Повний текст джерелаАнотація:
The development of microfluidic and nanofluidic devices is gaining remarkable attention due to the emphasis put on miniaturization of conventional energy conversion and storage processes. A microfluidic fuel cell can integrate flow of electrolytes, electrode-electrolyte interactions, and power generation in a microfluidic channel. Such microfluidic fuel cells can be categorized on the basis of electrolytes and catalysts used for power generation. In this work, for the first time, a single microfluidic fuel cell was harnessed by using different fuels like glucose, microbes and formic acid. Herein, multi-walled carbon nanotubes (MWCNT) acted as electrode material, and performance investigations were carried out separately on the same microfluidic device for three different types of fuel cells (formic acid, microbial and enzymatic). The fabricated miniaturized microfluidic device was successfully used to harvest energy in microwatts from formic acid, microbes and glucose, without any metallic catalyst. The developed microfluidic fuel cells can maintain stable open-circuit voltage, which can be used for energizing various low-power portable devices or applications.
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Guima, Katia-Emiko, Pedro-Henrique L. Coelho, Magno A. G. Trindade, and Cauê Alves Martins. "3D-Printed glycerol microfluidic fuel cell." Lab on a Chip 20, no. 12 (2020): 2057–61. http://dx.doi.org/10.1039/d0lc00351d.
Повний текст джерела
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Kamitani, Ai, Satoshi Morishita, Hiroshi Kotaki, and Steve Arscott. "Microfabricated microfluidic fuel cells." Sensors and Actuators B: Chemical 154, no. 2 (June 2011): 174–80. http://dx.doi.org/10.1016/j.snb.2009.11.014.
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Wang, Yifei, Shijing Luo, Holly Y. H. Kwok, Wending Pan, Yingguang Zhang, Xiaolong Zhao, and Dennis Y. C. Leung. "Microfluidic fuel cells with different types of fuels: A prospective review." Renewable and Sustainable Energy Reviews 141 (May 2021): 110806. http://dx.doi.org/10.1016/j.rser.2021.110806.
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Mousavi Shaegh, Seyed Ali, Nam-Trung Nguyen, and Siew Hwa Chan. "Air-breathing microfluidic fuel cell with fuel reservoir." Journal of Power Sources 209 (July 2012): 312–17. http://dx.doi.org/10.1016/j.jpowsour.2012.02.115.
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Phirani, J., and S. Basu. "Analyses of fuel utilization in microfluidic fuel cell." Journal of Power Sources 175, no. 1 (January 2008): 261–65. http://dx.doi.org/10.1016/j.jpowsour.2007.08.099.
Повний текст джерела
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Feali, M. S. "Transient Response of Microfluidic Fuel Cell." Russian Journal of Electrochemistry 56, no. 5 (May 2020): 437–46. http://dx.doi.org/10.1134/s1023193520030040.
Повний текст джерелаДисертації з теми "Microfluidic fuell cell"
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Lim, Keng Guan. "Microfluidic fuel cell." View abstract/electronic edition; access limited to Brown University users, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3319104.
Повний текст джерела
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Sprague, Isaac Benjamin. "Characterization of a microfluidic based direct-methanol fuel cell." Online access for everyone, 2008. http://www.dissertations.wsu.edu/Thesis/Summer2008/I_Sprague_072208.pdf.
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Ebrahimi, Khabbazi Ali. "Comprehensive numerical study of microfluidic fuel cells." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/27537.
Повний текст джерелаАнотація:
The microfluidic fuel cell or laminar flow-based fuel cell is a membraneless fuel cell which typically consists of two electrodes mounted within a T- or Y-shaped microchannel. Aqueous fuel and oxidant are introduced from the two inlets of the channel and flow together side-by-side toward the end of the channel. The Reynolds number in the microchannel is low, and hence viscous forces are dominant over the inertial forces. This causes the anolyte and catholyte form a co-laminar flow inside the microchannel which is required to maintain the separation of the fuel and oxidant and limit the reactions to the appropriate electrodes.
In this work, a comprehensive numerical model of the microfluidic fuel cell is developed using COMSOL Multiphysics. This model accounts for the mass and momentum transport phenomena inside the device as well as the electrochemical reaction kinetics which are described by the Butler-Volmer equations. Potential equations are used to model both the ionic conduction in the electrolyte and the electrical conduction in the solid electrodes. The validity of the developed model is first checked by verifying it against the numerical and experimental results previously reported in the literature. The model is then used to assess the effect of different modifications, which have been applied on the microfluidic fuel cell since its advent, by calculating the polarization curves associated with each modification.
In this thesis, a novel design of microfluidic fuel cell with a tapered channel is also proposed. Using the numerical model, it is shown that the tapered geometry improves the fuel utilization by up to four times in addition to a substantial improvement in the power density.
A similar numerical model is developed to study the performance of a microfluidic fuel cell with flow-through porous electrodes. Using this model, the effect of porosity on the net power output of the fuel cell is investigated and an optimum value for porosity is calculated. The model presented is a valuable tool, as it can be used to study the effect of any modifications on the cell performance before fabricating and testing the new design in an extensive experimental study.
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Battistelli, Elisa. "Microfluidic microbial fuel cell fabrication and rapid screening of electrochemically microbes." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/7301/.
Повний текст джерелаАнотація:
The demand for novel renewable energy sources, together with the new findings on bacterial electron transport mechanisms and the progress in microbial fuel cell design, have raised a noticeable interest in microbial power generation.
Microbial fuel cell (MFC) is an electrochemical device that converts organic substrates into electricity via catalytic conversion by microorganism. It has represented a continuously growing research field during the past few years.
The great advantage of this device is the direct conversion of the substrate into electricity and in the future, MFC may be linked to municipal waste streams or sources of agricultural and animal waste, providing a sustainable system for waste treatment and energy production.
However, these novel green technologies have not yet been used for practical applications due to their low power outputs and challenges associated with scale-up, so in-depth studies are highly necessary to significantly improve and optimize the device working conditions. For the time being, the micro-scale MFCs show great potential in the rapid screening of electrochemically active microbes.
This thesis presents how it will be possible to optimize the properties and design of the micro-size microbial fuel cell for maximum efficiency by understanding the MFC system. So it will involve designing, building and testing a miniature microbial fuel cell using a new species of microorganisms that promises high efficiency and long lifetime. The new device offer unique advantages of fast start-up, high sensitivity and superior microfluidic control over the measured microenvironment, which makes them good candidates for rapid screening of electrode materials, bacterial strains and growth media.
It will be made in the Centre of Hybrid Biodevices (Faculty of Physical Sciences and Engineering, University of Southampton) from polymer materials like PDMS. The eventual aim is to develop a system with the optimum combination of microorganism, ion exchange membrane and growth medium. After fabricating the cell, different bacteria and plankton species will be grown in the device and the microbial fuel cell characterized for open circuit voltage and power. It will also use photo-sensitive organisms and characterize the power produced by the device in response to optical illumination.
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González, Guerrero MªJosé. "Enzymatic microfluidic fuel cells: from active to passive power sources." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/322082.
Повний текст джерелаАнотація:
Esta tesis presenta el desarrollo y la fabricación de pilas de combustibles microfluídicas para aplicaciones portátiles de baja potencia. En concreto, pilas biológicas que utilizan las enzimas en la degradación de la glucosa. El trabajo está dividido en dos secciones dependiendo de si los dispositivos fabricados son activos, es decir, los reactivos son suministrados a la micropila por bombeo (Capítulo 2 y 3). O si por el contrario los reactivos fluyen sin necesidad de mecanismos externos los dispositivos serán pasivos (Capítulo 4 y 5).
En el primer capítulo de la tesis se ha llevado a cabo la primera aproximación en el desarrollo de micro pilas de combustible glucosa/O2 con el objetivo de hacer posible las primeras medidas electroquímicas con enzimas. La pila microfluídica fue construida sobre un sustrato de vidrio en el cual se grabaron electrodos de oro mediante técnicas de microfabricación. Por otro lado, se utilizó fotolitografía suave para la fabricación de los canales (con forma de Y) en PDMS. Esta forma de canal permitió fluir dos soluciones en paralelo usando una bomba de jeringa. Como primera aproximación, las enzimas se encontraban fluyendo de manera continua a través del canal. Eso provocaba experimentos caros y dificultaba su posible aplicación portátil. De este modo, el siguiente aspecto en abordarse fue la inmovilización de los biocatalizadores sobre los electrodos de la micro pila.
El Capítulo 2 presenta la fabricación de una pila de combustible que posee los biocatalizadores inmovilizados en la superficie de los electrodos lo cual hace que los biocatalizores sean aprovechados más eficientemente que en la anterior pila. Los electrodos se han fabricado utilizando resina pirolizada y se han usado por primera vez con éxito en pilas microfluídicas enzimáticas de este tipo. La pila está compuesta por diferentes capas de material plástico laminado que han sido cortadas usando un plotter de corte. Esto hace que la fabricación del dispositivo sea rápida, barata y compatible con la manufacturación a gran escala. El canal microfluídico se ha definido también sobre este tipo de material plástico, evitando el largo proceso litográfico relacionado con el PDMS. Por otro lado, el canal (en forma de Y) permite optimizar la potencia que obtenemos de la pila cuando bombeamos dos soluciones diferentes. Por otro lado, el dispositivo necesita ser simplificado para finalmente obtener una fuente de energía portátil. Con este objetivo se abordó la siguiente fase de la tesis.
El Capítulo 4 describe la fabricación de una pila microfluídica implementada utilizando sustratos de papel a través de los cuales fluyen los reactivos (de manera pasiva) por efecto capilar. Los componentes de la pila se cortaron utilizando un plotter de corte, lo que permitía fabricar dispositivos con mucha rapidez. Se probó el buen funcionamiento de una pila de combustible de papel y enzimática obteniendo valores de potencia similares a los presentados en el Capítulo 3 (donde las soluciones eran bombeadas). A partir de aquí el trabajo se centró en aproximar la pila de papel a la simplicidad de los test de flujo lateral. Así que la micro pila fue adaptada y operada con éxito usando una única solución, generando energía de una bebida comercial.
El Capítulo 5 presenta una micropila de combustible fabricada en papel mucho más sofisticada y pequeña que la del capítulo anterior. Se probó satisfactoriamente una nueva combinación de biocatalizadores que permitió trabajar utilizando muestras a pH neutro. Además, el tamaño compacto del sistema abrió la posibilidad de operar la pila de combustible con fluidos fisiológicos como por ejemplo la sangre. Finalmente, se ha demostrado que es posible tener una pila preparada para alimentar dispositivos que requieran poca demanda de energía. Sin embargo, todavía se deben hacer esfuerzos para acercar esta pila a un mundo real, debido principalmente a que el tiempo de vida de las enzimas es todavía limitado.This thesis presents the development and fabrication of microfluidic fuel cells for low power and portable applications. Specifically, biological fuel cells that use enzymes for glucose degradation. This work is divided in two sections depending on whether the fabricated devices are active, i. e. the reagents are supplied into the micro fuel cell by pumping (Chapters 2 and 3). If, on the contrary, the reagents flow without needing external mechanisms they are passive devices (Chapters 4 and 5). In the first chapter of the thesis the first approach in the development of glucose/O2 micro fuel cells was conducted in order to allow for the initial electrochemical measurements with enzymes. The microfluidic fuel cell was fabricated using a glass substrate in which gold electrodes were impressed using microfabrication techniques. On the other hand, soft lithography was used to fabricate the Y-shaped PDMS channels. This channel shape enabled to flow two solutions in parallel using a syringe pump. The enzymes were continuously flowing through the channel causing expensive experiments in addition to hindering its possible portable application. Thereby, the biocatalysts immobilization on the electrodes was next addressed in this thesis. Chapter 2 presents the fabrication of a micro fuel cell with enzymes trapped on the electrode surfaces which lead to an effective use of the biocatalysts. The electrodes were fabricated using pyrolyzed resists and were successfully used for the first time in enzymatic microfluidic fuel cells of this kind. The fuel cell was formed by different layers of plastic laminated materials cut using a cutter plotter. This promotes a fast and inexpensive device fabrication which is compatible with large scale manufacturing. The microfluidic channel was also defined on this type of plastic materials, thus avoiding the long lithographic process related to the PDMS. Moreover, this Y-shaped channel allows to optimize the power obtained from the fuel cell when two different solution are pumped into the system. Therefore, the following aspect to be addressed was the biocatalyst immobilization over the electrodes of the micro fuel cell Chapter 4 describes the construction of a microfluidic fuel cell fabricated using paper substrates. The reagents flow through this paper (in a passive way) by capillary action. The fuel cell components were cut using a cutting plotter which allows fabricating devices much faster. The proper functioning of this paper-based microfluidic fuel cell was verified obtaining similar power values to those presented in Chapter 3 (were solution were pumped). From here, the work focused on bringing the paper fuel cell closer to the simplicity of lateral flow tests. The fuel cell was then adapted and successfully operated using a single solution, generating energy from a commercial drink. Chapter 5 presents a microfluidic paper-based fuel cell smaller and more sophisticated than the one presented in previous chapter. A new combination of enzyme was tested which allowed to work with samples at neutral pH. Additionally, the compact size of the system opened the possibility to operate the paper fuel cell with physiological fluids, such as blood. Finally, it was demonstrated that was possible to have a fuel cell ready to fed devices demanding low energy. However, more efforts have to be done in the field to approach this fuel cell to a real world mainly due to the still limited lifetime of the enzymes.
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Garcia, Marine. "Développement d’une plateforme d’imagerie pour la caractérisation du transfert de masse dans les microsystèmes : application aux piles à combustible microfluidiques." Electronic Thesis or Diss., Paris, HESAM, 2024. http://www.theses.fr/2024HESAE007.
Повний текст джерелаАнотація:
Les piles à combustible sont des dispositifs qui transforment l'énergie stockée dans un oxydant et un réducteur en électricité grâce à des réactions électrochimiques. La technologie la plus mature pour réaliser cette conversion est la pile à hydrogène à membrane échangeuse de protons (PEMFC), mais d'autres systèmes alternatifs émergent. En particulier, les piles à combustible microfluidiques (PCM) ont permis de s’affranchir des problématiques liées à l’utilisation d’une membrane et du stockage gazeux grâce à l’utilisation de réactifs liquides à température et pression ambiante. Les dimensions du canal (1-5 mm de large et 20-100 µm de haut) permettent un écoulement co-laminaire des deux réactifs et de l’électrolyte liquides dans un micro-canal contenant les électrodes. Les PCMs n'ont donc pas de membrane et leurs performances sont dirigées par le transport de charges et de masse.À ce jour, il est difficile de caractériser expérimentalement tous les phénomènes physiques qui ont lieu dans la PCM car les méthodes existantes sont plutôt basées sur la caractérisation électrochimique. Ces méthodes permettent d'avoir une caractérisation globale du système mais ne fournissent pas d'informations précises sur les phénomènes de transport de masse dans le canal. Pour étudier le transport de masse, la modélisation numérique est généralement utilisée et permet de simuler le champ de concentration et les performances de la PCM pour différentes architectures et conditions opératoires. Toutefois, l'utilisation de ces modèles repose sur la connaissance de paramètres in-situ tels que le coefficient de diffusion D et le coefficient de réaction k0. Dans les travaux numériques, ces paramètres sont généralement approximés, ce qui permet une appréhension plutôt qualitative des phénomènes de transport. De plus, ces études numériques n'ont à ce jour pas été vérifiées avec des études expérimentales.Ainsi, le principal verrou scientifique de cette thèse repose sur le développement de méthodes d'imagerie quantitatives pour la caractérisation du champ de concentration dans une PCM en fonctionnement.Pour répondre à ce besoin, une plateforme d'imagerie basée sur la spectroscopie ainsi que trois méthodes de caractérisation ont été développées dans cette thèse. Dans un premier temps, les travaux se sont concentrés sur le développement d'un banc de spectroscopie pour étudier le phénomène d'interdiffusion. Cette étude a permis d'estimer le coefficient de diffusion du permanganate de potassium dans l'acide formique. Ces solutions ont été spécifiquement choisies car ceux sont celle utilisées dans la PCM développées pour la suite de l’étude.Le banc de spectroscopie a ensuite été adapté pour étudier le champ de concentration 2D en régime permanent d'une PCM en fonctionnement. Un modèle analytique du transfert de masse (advection/réaction/diffusion) couplé au champ de concentration 2D a ainsi permis de déterminer le taux de réaction. Les variations de concentration mises en jeu étant parfois très faibles (quelques micro-moles), une autre technique de caractérisation a été mis en place pour diminuer le bruit de mesure.Afin d'améliorer le rapport signal sur bruit, une méthode basée sur la modulation du champ de concentration a été développée. La démodulation du signal a permis de réduire significativement le bruit et des concentrations de 20 µM ont ainsi été estimées. Un modèle analytique décrivant le champ modulé a été établi afin d'implémenter une méthode inverse. La méthode proposée a permis de retrouver le taux de réaction associé à la variation de concentration.En conclusion, les méthodes de caractérisation proposées dans cette thèse permettent d'estimer quantitativement le transfert de masse et la cinétique de réaction à partir du champ de concentration 2D d'une PCM en fonctionnement. Cette technique a été appliquée au PCM, mais elle peut être transférée à un système micrométrique dans lequel les phénomènes de diffusion-advection-réaction ont lieuFuel cells are devices that convert the energy stored in an oxidant and a reductant into electricity through electrochemical reactions. The most mature technology for this conversion is the proton exchange membrane fuel cell (PEMFC), but other alternative systems are emerging. In particular, microfluidic fuel cells (MFCs) have overcome the problems associated with the use of a membrane and gas storage by using liquid reagents at ambient temperature and pressure. The dimensions of the channel (1-5 mm wide and 20-100 µm high) allow co-laminar flow of the two liquid reagents and the electrolyte in a microchannel containing the electrodes. Therefore, PCMs do not need membrane to separate reactants and performances are driven by charge and mass transport.Experimental characterization of all the physical phenomena involved in PCMs is difficult because actuals methods are more based on electrochemical characterisation. These methods provide an overall characterisation of the system but they do not give precise information on the mass transport phenomena occurring in the channel. To investigate concentration field, numerical modelling is generally used. Numerical methods evaluate the impact of the geometry or the operating conditions on MFC performances. However, the use of these models relies on the knowledge of in-situ parameters such as the diffusion coefficient D and the reaction rate k0. In numerical studies, these parameters are generally approximated leading to a qualitative understanding of the transport phenomena. Furthermore, these numerical studies have not yet been verified by experimental studies.Thus, the main scientific challenge of this thesis is to develop quantitative imaging methods for characterising the concentration field in an operating PCM.To meet this need, an imaging platform based on spectroscopy and three characterisation methods were developed in this thesis. First of all, the work focused on developing an experimental setup based on spectroscopy to study the interdiffusion phenomenon. This study reports the estimation of the diffusion coefficient of potassium permanganate in formic acid. These solutions were specifically chosen because they are used in the PCM developed for the rest of the study.The imaging plateform was then adapted to study the in operando MFC 2D concentration field in steady-state. An analytical mass transfer model (advection/reaction/diffusion) coupled to the 2D concentration field was used to determine the reaction rate. As the concentration variations involved can be very small (few micro-moles), another characterisation technique was implemented to reduce the measurement noise.To improve the signal-to-noise ratio, a method based on modulation of the concentration field was developed. Demodulation of the signal significantly reduced the noise and concentrations of 20 µM were estimated. An analytical model describing the modulated field was established in order to implement an inverse method. The proposed method made it possible to recover the reaction rate associated with the concentration variation.To conclude, the proposed characterisation methods enable the estimation of the mass transfer and the reaction kinetics using the 2D concentration field from an in operando MFC. This technique has been applied to the MFC, but it can be transferred to a micrometric system in which diffusion-advection-reaction phenomena take place
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Ghorbanian-Mashhadi, Setareh. "Microfluidic probe for direct write of soft cell scaffolds." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97140.
Повний текст джерелаАнотація:
3D cell cultures replicate the in-vivo physiology much more accurately than 2D cell cultures; but it remains challenging to recreate the 3D in-vivo tissue architecture of soft tissues in-vitro. Different methods have been developed to print cell scaffolds in 3 dimensions, the two most popular being inkjet printing and direct extrusion. Extrusion is promising because 3D structures can be written directly; however, they incur a high shear stress, which was shown to damage or even kill cells. We have designed and fabricated a novel microfluidic probe (MFP) and developed a direct write method to dispense alginate fibers seeded with cells and to construct a 3D cell scaffold. This system allows for low shear stress deposition of cells inside of a fiber onto the surface because a liquid is used, which gelates only after extrusion while still being surrounded by an ensheathing liquid. The MFP comprises two main intersecting microchannels, one for the alginate precursor solution and one for the sheath flow of calcium chloride, which triggers the gelation of the alginate. The main branching point is designed so as to ensheath the alginate solution, which solidifies into a fiber that can be varied in diameter of around 100 μm before exiting through the nozzle of the MFP. We further incorporated a declogging microchannel, which proved to be of great practical importance and through which we flow a chelating agent that binds the calcium and leads to the dissolution of alginate that may have gelated inside of the device. Throughout this project, i) different probe designs were considered and tested, ii) different fabrication methods were examined and used to fabricate the different probes, iii) the fiber dimensions were measured and characterized as a function of the liquid flow rates, iv) different parameter of the probe, and v) liquid were examined to reduce curl formation during direct writing, , vi) glass substrate was surface coated to optimize the binding of the fibers onto the surface, vii) and multiple layers of fiber were deposited onto the glass substrate. Finally cell viability was optimized and cells were loaded directly within 3D scaffolds and shown to grow.Les cultures cellulaires tridimensionnelles (3D) reproduisent de manière plus fidèle la physiologie in vivo que les cultures bi-dimentionnelles (2D) faites enboîtes de Pétri, mais cet architecture 3D reste difficile à recréer in vitro. Différentes méthodes ont été développées pour imprimer des échafaudages cellulaires 3D. Des Bio-imprimeurs qui extrudent des matières biologiques contenant des cellules se sont, entre autres, montrés très prometteurs. Cependant, lors de l'extrusion, les forces de cisaillement appliquées sur les cellules sont telles qu'elles peuvent endommager ou même tuer les cellules. Nous avons conçu et fabriqué une nouvelle sonde microfluidique (Microfluidic Probe) et avons développé une méthode pour imprimer des fibres d'alginate contenant des cellules et ainsi construire un échafaudage cellulaire 3D. Ce système permet de produire et déposer des fibres d'alginate contenant des cellules avec moins de contrainte de cisaillement sur des cellules. La MFP est composée de deux principaux microcanaux qui se croisent, l'un apportant le précurseur d'alginate et l'autre l'agent gélifiant (chlorure de calcium). Le point debranchement est conçu de manière à entourer la solution d'alginate qui se solidifie en une fibre de diamètre variable d'environ 100 μm avant de sortir àl'embouchure de la MFP. Nous avons également incorporé un troisième microcanal qui sert au décolmatage, par lequel nous circulons de l'EDTA3 (éthylènediaminetétraacétate), un chélateur de calcium qui dissout l'alginate bloqué à l'intérieur de l'appareil. Au cours de ce projet de recherche, nous avons i) considéré et testé différents designs pour notre sonde, ii) examiné et utilisé différentes méthodes de fabrication, iii) mesuré et caractérisé la dimension des fibres en fonction du débit des liquides, iv) testé différents paramètres de la sonde, et v) testé des liquides pour réduire la formation d'ondulations pendant l'impression, vi) modifié la surface du verre pour optimiser l'adhésion des fibres d'alginate et vii) y avons déposé plusieurs couches de fibres. Finalement, nous avons démontré que des cellules ensemencées directement dans l'échafaudage 3D avec notre sonde pouvaient survivre et proliférer.
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Qasaimeh, Mohammad Ameen. "Microfluidic quadrupoles and their applications in cell chemotaxis studies." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=121369.
Повний текст джерелаАнотація:
Microfluidic systems open up new possibilities for in vitro cell biology research, mainly due to their ability to control the cellular microenvironment at physiologically relevant spatiotemporal scales. As such, several microfluidic systems have been introduced for the generation of concentration gradients and have been used for cell chemotaxis studies. However, these methods typically involve a trade-off between temporal control of the gradient and minimizing the applied shear stresses on the cells, and often require culturing cells in micro-channels. In this dissertation, we develop microfluidic quadrupoles (MQs) and demonstrate their first use in a laboratory setting. Two MQs with different configurations are presented; a lateral MQ that is associated with a stagnation point at its center, and a linear MQ with a stagnation zone bounded by two hydrodynamically confined streams. We also introduce "floating" concentration gradients of biochemicals that can be produced using MQs by injecting a solute through one of the poles. Floating gradients are controllable, associated with minimal shear stresses, can be applied to any flat substrate in a channel-less microfluidic system, and can be rapidly adjusted and moved. We used the lateral MQ to apply floating gradients of Interleukin-8 to cultured human neutrophils in a culture dish, and developed novel chemotaxis assays with stationary and moving gradients. Furthermore, we observed the real-time dynamics of neutrophils during adhesion, polarization, and migration, and showed that neutrophils migrate longer distances when following moving gradients in comparison to stationary gradients.The work presented in this dissertation introduces a new area of research in the field of fluidic multipoles and floating gradients, as well as their applications in the biomedical sciences. Furthermore, this work sets the foundation for developing novel biological and cell chemotaxis assays using moving concentration gradients. These assays can then be combined with pharmacological studies and help to further understand the mechanisms of cellular polarization, migration, and desensitization.Les systèmes microfluidiques ouvrent de nouvelles possibilités pour la recherche in vitro en biologie cellulaire, notamment par leur capacité à contrôler le microenvironnement cellulaire à des échelles spatiotemporelles physiologiquement pertinentes. En ce sens, plusieurs systèmes microfluidiques ont été introduits pour la génération de gradients de concentration et ont été utilisés pour des études sur la chimiotaxie cellulaire. Cependant, ces méthodes font face à un compromis entre le contrôle temporel du gradient et la minimisation de la contrainte de cisaillement appliqué sur les cellules. De plus, elles requièrent souvent de mettre les cellules en culture dans des microcanaux. Dans cette dissertation, nous démontrons la première utilisation des quadripôles microfluidiques (QM) dans un contexte expérimental. Nous présentons deux QM avec des configurations différentes : un QM latéral associé à un point de stagnation en son centre, et un QM linéaire avec une zone de stagnation reliée par deux flux hydrodynamiquement confinés. Nous présentons aussi des gradients de concentration « flottants » de produits biochimiques réalisés à l'aide de QM en injectant un soluté à travers un des pôles. Les gradients mobiles sont réglables, associés à une contrainte de cisaillement minimale, peuvent être appliqués à n'importe quel substrat plat dans un système microfluidique sans canal, et peuvent être rapidement ajustés et déplacés. Nous avons utilisé le QM latéral pour appliquer des gradients de concentration mobiles de l'Interleukin-8 à des neutrophiles humains dans une plaque de culture, et avons développé de nouveaux tests pour mesurer la chimiotaxie avec des gradients fixes et mobiles. De plus, nous avons observé la dynamique des neutrophiles en temps réel durant l'adhésion, la polarisation, et la migration, et avons démontré que les neutrophiles migrent sur de plus longues distances lorsqu'ils suivent des gradients mobiles plutôt que des gradients fixes.Les travaux présentés dans cette dissertation ouvrent un nouveau champ de recherche dans le domaine des multipôles fluidiques et des gradients mobiles, ainsi que leur application dans les sciences biomédicales. De plus, ces travaux sont une base pour le développement de nouveaux tests biologiques et mesurant la chiomiotaxie utilisant des gradients de concentration mobiles. Ces tests peuvent ensuite être combinés à des études pharmacologiques pour aider à mieux comprendre les mécanismes de polarisation, migration, et désensibilisation cellulaire.
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Mirzaei, Maryam. "Poduction of human Interleukin-7 in insect cells and fabrication of microfluidic systems for high throughput cell screening." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66846.
Повний текст джерелаАнотація:
Biotechnology is defined as the use of biological techniques to engineer or manufacture a product. Development and optimization of systems in biotechnology have witnessed extraordinary advances over the last few decades. It can be further enhanced through combination with micro/nanotechnology, enabling de vices miniaturization to the microscale that leads to a rapid and cost effective analysis using microfluidic systems. Microfluidic systems offer high parallelization and high throughput screening assays. This thesis aims to expand biotechnology in two main areas: (i) preparation of a suitable expression system for production of human Interleukin-7 (hIL-7) in insect cells, and (ii) fabrication of microfluidic systems for integration with biotechnology for high throughput cell screening assays using insect and yeast cells. Human IL-7 has multiple immune-enhancing properties, which make it an ideal candidate for immunotherapy in a variety of clinical situations. Currently, there is no convenient and cost effective method for producing hIL-7. We present the production of hIL-7 in insect cells for the first time. We used a baculovirus expression vector system (BEVS) and a non-lytic system to produce hIL-7 in insect cells. In addition, we investigated large scale production of hIL-7 using various bioreactors. The resulting insect cells produce hIL-7 at different rates. To select highly productive single cells, the presently existing methods are time consuming, labor intensive and have low throughput capacity. In addition, these methods need special equipment for operation, as well as large amounts of chemicals. In order to rapidly select cells that produce high amounts of hIL-7, we designed and fabricated a new microfluidic system based on a polyethylene glycol (PEG) microwell array and a track etched membrane. Using this system, single cells can be selected on the basis of their protein secretion rate after a few hours only witLa biotechnologie est définie comme l'utilisation de techniques biologiques pour développer ou fabriquer un produit. Le développement et l'optimisation de systèmes dans la biotechnologie ont été témoins d'avances extraordinaires pendant les dernières dix années. Ils peuvent être davantage améliorés par la combinaison avec la micro/nanotechnology, qui nous permet de miniaturiser des artifices à la microéchelle qui cause une analyse rapide, efficace et à un bon prix en utilisant les systèmes microfluidiques. Les systèmes microfluidiques offrent une haute parallélisassion et un haut débit de criblage. Cette thèse a pour but de développer la biotechnologie dans deux régions principales : (i) la préparation d'un système d'expression convenable pour la production d'Interleukine-7 humaine (hIL-7) dans les cellules d'insectes et (ii) la fabrication de systèmes microfluidiques, intégrant la biotechnologie, pour le criblage à haut débit de cellules en utilisant des cellules de levure et d'insecte.L'IL-7 humaine a des propriétés activatrices du système immunitaire, qui le font un candidat idéal à l'immunothérapie dans une variété de cas cliniques. Actuellement, il n'y a aucune méthode convenable et peu coûteuse pour produire hIL-7Nous présentons la production de hIL-7 dans les cellules d'insectes pour la première fois. Nous avons utilisé un système de vecteurs d'expression baculovirus (BEVS) et un système non-lytique pour produire hIL-7 dans des cellules d'insectes. En plus nous avons enquêté la production grande échelle de hIL-7 en utilisant différents bioréacteurs.Les cellules d'insectes produites génèrent l'hIL-7 à différents taux. Les méthodes existantes pour choisir les cellules extrêmement productives sont très lentes avec une faible capacité de traitement en plus d'exiger de l'équipement spécifique pour l'opération, aussi bien que de grandes quantités de produits c
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Jones, A.-Andrew D. III (Akhenaton-Andrew Dhafir). "Design of a microfluidic device for the analysis of biofilm behavior in a microbial fuel cell." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/88279.
Повний текст джерелаАнотація:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 83-90).
This thesis presents design, manufacturing, testing, and modeling of a laminar-flow microbial fuel cell. Novel means were developed to use graphite and other bulk-scale materials in a microscale device without loosing any properties of the bulk material. Micro-milling techniques were optimized for use on acrylic to achieve surface roughness averages as low as Ra = 100nm for a 55 [mu]m deep cut. Power densities as high as 0.4mW · m⁻², (28mV at open circuit) in the first ever polarization curve for a laminar-flow microbial fuel cell. A model was developed for biofilm behavior incorporating shear and pore pressure as mechanisms for biofilm loss. The model agrees with experimental observations on fluid flow through biofilms, biofilm structure, and other biofilm loss events.
by A-Andrew D. Jones, III.
S.M.
Книги з теми "Microfluidic fuell cell"
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Kjeang, Erik. Microfluidic Fuel Cells and Batteries. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06346-1.
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Kjeang, Erik. Microfluidic Fuel Cells and Batteries. Springer London, Limited, 2014.
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Kjeang, Erik. Microfluidic Fuel Cells and Batteries. Springer, 2014.
Знайти повний текст джерелаЧастини книг з теми "Microfluidic fuell cell"
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Kjeang, Erik, and Jin Wook Lee. "Microfluidic Fuel Cells." In Encyclopedia of Microfluidics and Nanofluidics, 1944–53. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/978-1-4614-5491-5_935.
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Kjeang, Erik, and Jin Wook Lee. "Microfluidic Fuel Cells." In Encyclopedia of Microfluidics and Nanofluidics, 1–11. Boston, MA: Springer US, 2014. http://dx.doi.org/10.1007/978-3-642-27758-0_935-5.
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Goel, Sanket. "Microfluidic Microbial Fuel Cell: On-chip Automated and Robust Method to Generate Energy." In Microbial Fuel Cell, 229–47. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-66793-5_12.
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Shaegh, Seyed Ali Mousavi, and Nam-Trung Nguyen. "Materials for Microfluidic Fuel Cells." In Materials for Low-Temperature Fuel Cells, 185–214. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527644308.ch09.
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Kjeang, Erik. "Introduction." In Microfluidic Fuel Cells and Batteries, 1–5. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06346-1_1.
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Kjeang, Erik. "Theory." In Microfluidic Fuel Cells and Batteries, 7–15. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06346-1_2.
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Kjeang, Erik. "Fabrication and Testing." In Microfluidic Fuel Cells and Batteries, 17–24. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06346-1_3.
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Kjeang, Erik. "Devices." In Microfluidic Fuel Cells and Batteries, 25–49. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06346-1_4.
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Kjeang, Erik. "Modeling." In Microfluidic Fuel Cells and Batteries, 51–55. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06346-1_5.
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Kjeang, Erik. "Research Trends and Directions." In Microfluidic Fuel Cells and Batteries, 57–67. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06346-1_6.
Повний текст джерелаТези доповідей конференцій з теми "Microfluidic fuell cell"
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Brushett, Fikile R., Adam S. Hollinger, Larry J. Markoski, and Paul J. A. Kenis. "Microfluidic Fuel Cells as Microscale Power Sources and Analytical Platforms." In ASME 2009 Second International Conference on Micro/Nanoscale Heat and Mass Transfer. ASMEDC, 2009. http://dx.doi.org/10.1115/mnhmt2009-18007.
Повний текст джерелаАнотація:
A continuously growing need for high energy density miniaturized power sources for portable electronic applications has spurred the development of a variety of microscale fuel cells. For portable applications, membrane-based fuel cells using small organic fuels (i.e., methanol, formic acid) are among the most promising configurations as they benefit from the high energy density and easy storage of the liquid fuels. Unfortunately, the performance of these fuel cells is often hindered by membrane-related issues such as water management (i.e., electrode dry-out / flooding) and fuel crossover. Furthermore, high costs of, for example, catalysts and membranes as well as durability concerns still hinder commercialization efforts. To address these challenges we have developed membraneless laminar flow-based fuel cells (LFFCs), which exploit microscale transport phenomena (laminar flow) to compartmentalize streams within a single microchannel. The properties of various fuel and media flexible LFFCs will be presented and novel strategies for improving fuel utilization and power density will be discussed. Furthermore, the performance of a scaled-out 14-channel LFFC prototype is presented. We have also developed a microfluidic fuel cell as a powerful analytical platform to investigate and optimize the complex processes that govern the performance of catalysts and electrodes in an operating fuel cell. This platform bridges the gap between a conventional 3-electrode electrochemical cell and a fuel cell, as it allows for standard electrochemical analysis (e.g., CV, CA, EIS) as well as fuel cell analysis (e.g., IV curves).
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Weinmu¨ller, Christian, Nicole R. Bieri, and Dimos Poulikakos. "On Two Phase Flow Regimes in a Microscale Direct Methanol Fuel Cell." In ASME 2008 6th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2008. http://dx.doi.org/10.1115/icnmm2008-62193.
Повний текст джерелаАнотація:
The area of microfluidics has experienced a tremendous increase in research activities in recent years with a wide range of applications, such as micro heat exchangers and energy conversion devices, microreactors, lab-on-chip devices, micro total chemical analysis systems (μTAS) etc. The occurrence of two phase flow can lead to several mechanisms enhancing or extending the performance of single phase microfluidic devices [1]. On the other hand, in a micro fuel cell the second, non-immiscible phase is considered to hamper the performance of the fuel cell [2]. Regardless of its effect, two phase flows in microfluidics deserve special research attention.
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Kjeang, Erik, Ned Djilali, and David Sinton. "Planar and Three-Dimensional Microfluidic Fuel Cell Architectures." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42524.
Повний текст джерелаАнотація:
We propose planar and three-dimensional microfluidic fuel cell architectures based on the all-vanadium redox system. These fuel cells operate in a membraneless co-laminar flow configuration and are manufactured by economical microfabrication methods. Graphite rods, also known as mechanical pencil refills, are demonstrated as fuel cell electrodes in a three-dimensional array architecture with unique scale-up capabilities. We also demonstrate unprecedented power density levels by incorporation of porous electrodes in a planar microfluidic fuel cell.
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Lee, Jin wook, Deepak Krishnamurthy, Peter Hsiao, and Erik Kjeang. "A Parametric Study on Microfluidic Vanadium Fuel Cells." In ASME 2011 9th International Conference on Fuel Cell Science, Engineering and Technology collocated with ASME 2011 5th International Conference on Energy Sustainability. ASMEDC, 2011. http://dx.doi.org/10.1115/fuelcell2011-54395.
Повний текст джерелаАнотація:
A parametric variation of microfluidic vanadium fuel cells is studied. The present membraneless and catalyst-free fuel cell consists of a microfluidic channel network with two porous carbon paper electrodes. An aqueous vanadium redox pair as reactants is supplied to the porous electrodes in a flow-through configuration. The dimensions of porous carbon electrodes and microchannels are varied from the baseline design to investigate their impacts on the fuel cell performance. In addition, a dependency on the number of electrical contacts is examined. Numerical simulations are performed in parallel with experimental activities to understand the coupled effects of mass transport, electrochemistry, electron conduction, and fluid velocity field. The simulation results are compared with the measured data from each cell design for verification. An optimal cell design is discussed based on the current study and future research opportunities were proposed.
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Jones, A.-Andrew D., and Cullen R. Buie. "A Microfluidic Platform for Evaluating Anode Substrates for Microbial Fuel Cells." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-87781.
Повний текст джерелаАнотація:
Microbial fuel cell technology is a new technology for producing green energy from wastewater. While lab scale and commercial microbial fuel cells typically utilize graphite as the film substrate, it is difficult to rapidly prototype micro-patterned graphite and it has not been used to date. Our design sandwiches graphite sheets under a channel layer creating a microfluidic microbial fuel cell with graphite electrodes. The microfluidic microbial fuel cell uses Geobacter sulfurreducens fed with acetate in a phosphate buffer media. Ferricyanide is used as the catholyte so that the system is anodically limited. Current versus time and open circuit voltage are reported showing biofilm growth microbial fuel cell operation.
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Fuerth, D., and A. Bazylak. "Carbon Based Electrodes for Upscaling Microfluidic Fuel Cells." In ASME 2012 10th International Conference on Fuel Cell Science, Engineering and Technology collocated with the ASME 2012 6th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/fuelcell2012-91043.
Повний текст джерелаАнотація:
In this work, we present an experimental microfluidic fuel cell with a novel up-scaled porous electrode architecture that provides higher overall power output compared to conventional microfluidic fuel cells and a methodology for electrode material evaluation to inform designs for improved performance. Our proof-of-concept architecture is an up-scaled version of a previously presented flow-through cell with more than nine times the active electrode surface area. We employed 0.04M formic acid and 0.01M potassium permanganate as fuel and oxidant, respectively, dissolved in a 1M sulfuric acid electrolyte. Platinum black was employed as the catalyst for both anode and cathode. Carbon based porous electrodes including felt, cloth, fibre, and foam were compared to traditional Toray carbon paper in order to characterize their respective performances. We also discussed current densities normalized by electrode volume, which is appropriate for comparison of flow-through architectures. The traditional method of current normalization by projected electrode surface area is also presented.
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Salemmilani, Reza, and Barbaros Cetin. "Spiral Microfluidics Device for Continuous Flow PCR." In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17305.
Повний текст джерелаАнотація:
Polymerase-chain-Reaction (PCR) is a thermal cycling (repeated heating and cooling of PCR solution) process for DNA amplification. PCR is the key ingredient in many biomedical applications. One key feature for the success of the PCR is to control the temperature of the solution precisely at the desired temperature levels required for the PCR in a cyclic manner. Microfluidics offers a great advantage over conventional techniques since minute amounts of PCR solution can be heated and cooled with a high rate in a controlled manner. In this study, a microfluidic platform has been proposed for continuous-flow PCR. The microfluidic device consists of a spiral channel on a glass wafer with integrated chromium microheaters. Sub-micron thick microheaters are deposited beneath the micro-channels to facilitate localized heating. The microfluidic device is modeled using COMSOL Multiphysics®. The fabrication procedure of the device is also discussed and future research directions are addressed. With its compact design, the proposed system can easily be coupled with an integrated microfluidic device to be used in biomedical applications.
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Lee, Jin Wook, and Erik Kjeang. "Performance Improvements by Embedded Thin Film Current Collectors for Microfluidic Fuel Cells With Porous Electrodes." In ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2012 Heat Transfer Summer Conference and the ASME 2012 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icnmm2012-73162.
Повний текст джерелаАнотація:
In the present work, a chip embedded thin film current collector for vanadium fueled microfluidic fuel cells is proposed. Embedded current collectors are expected to increase the number of contact points with the porous electrodes and thereby reduce the overall contact resistance and ohmic losses of the cell. The micromachining based thin film process is compatible with the overall cell fabrication scheme, which is based on soft lithography, and does not require a substantial modification of the original cell design. The flow-through microfluidic fuel cell architecture with porous carbon paper electrodes is used as a proof-of-concept in this study. Our preliminary study shows that the peak power density of the cell with the current collector is increased by 79% at 300 μL min−1 compared to an otherwise identical cell without current collector, indicating that the contact resistance is significantly reduced. Electrochemical impedance spectroscopy analysis is carried out to estimate the overall cell ohmic resistance and confirms a 32% reduction using the current collectors.
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Sprague, Isaac B., and Prashanta Dutta. "Flow Through Nanoporous Electrodes in a Microfluidic Fuel Cell." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-85769.
Повний текст джерелаАнотація:
In this paper we present how advection in the electric double layer (EDL) affects the kinetic performance of electrochemical cells. To accomplish this we use a laminar flow fuel cell model based on the Poisson-Nernst-Planck and Frumkin-Butler-Volmer equations. The model contains nonlinear physics with very disparate length scales due to the complex 3-dimensional nature of the nano-porous device. To account for these difficulties, the full mathematical model is solved numerically using a novel numerical algorithm developed based on domain decomposition method. Numerical results show that the presence of an advection flux through nano-pores on the order of the EDL width yields some novel physics that affect the structure of electrode-electrolyte interface. We also show that electrolyte advection within the EDL can be used to enhance the kinetic performance of electrodes in electrochemical cells. In the device presented the peak power density can be increased significantly with flow velocity.
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Bazylak, Aimy, David Sinton, and Ned Djilali. "Membraneless Liquid-Fuel Microfluidic Fuel Cells: A Computational Study." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-59341.
Повний текст джерелаАнотація:
Presented in this paper is a computational analysis of a membraneless microfluidic fuel cell that uses the laminar nature of microflows to maintain the separation of fuel and oxidant streams. The fuel cell consists of a T-shaped microfluidic channel with liquid fuel and oxidant entering at separate inlets and flowing in parallel without turbulent or convective mixing. Electrodes are placed along the walls, and the resulting redox reactions provide the cell voltage and current. A concise electrochemical model of the key reactions and appropriate boundary conditions for the computational fluid dynamic (CFD) modelling of this system are developed and implemented into the numerical model. The coupled flow, species transport and chemical aspects of the microfluidic fuel cell are simulated. The effects of geometry and flow rates on fuel cell performance are investigated. Results indicate that the microfluidic fuel cell performance is limited by the transport of reactants through the concentration boundary layer to the electrodes. Three typical geometries were simulated, and it was found that increasing the aspect ratio of the channel cross-section from a square geometry to a rectangular one leads to more than a two-fold increase in fuel utilization. The two rectangular geometries simulated consist of a design with a high aspect ratio in the direction perpendicular to the plane of cross-stream diffusion as well as a design with a high aspect ratio in the direction parallel to the plane of cross-stream diffusion. The electrode placement and geometry play key roles with respect to mixing and fuel utilization. The design with a high aspect ratio in the direction perpendicular to the plane of cross-stream diffusion demonstrated relatively less cross-stream mixing compared to the other rectangular geometry, and had the potential for improved fuel utilization with appropriate electrode design. In addition, results suggest that fuel utilization can be increased from previous values by a factor of two or more. Decreasing the inlet velocity from 0.1 m/s to 0.02 m/s caused the fuel utilization to increase non-linearly from 8 % to 23 %, and only caused an increase of 3 % in cross-stream mixing at the outlet.
Звіти організацій з теми "Microfluidic fuell cell"
1
Abruna, Hector Daniel. Transport Phenomena and Interfacial Kinetics in Planar Microfluidic Membraneless Fuel Cells. Office of Scientific and Technical Information (OSTI), August 2013. http://dx.doi.org/10.2172/1089301.
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