Relevant bibliographies by topics / Diffusive gradients in thin films

Academic literature on the topic 'Diffusive gradients in thin films'

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Published: 4 June 2021
Last updated: 20 February 2023

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Journal articles on the topic "Diffusive gradients in thin films"

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Puy, Jaume, Ramiro Uribe, Sandrine Mongin, Josep Galceran, Joan Cecília, Jacqueline Levy, Hao Zhang, and William Davison. "Lability Criteria in Diffusive Gradients in Thin Films." Journal of Physical Chemistry A 116, no. 25 (March 27, 2012): 6564–73. http://dx.doi.org/10.1021/jp212629z.

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Li, Cai, Shiming Ding, Liyuan Yang, Yan Wang, Mingyi Ren, Musong Chen, Xianfang Fan, and Eric Lichtfouse. "Diffusive gradients in thin films: devices, materials and applications." Environmental Chemistry Letters 17, no. 2 (December 11, 2018): 801–31. http://dx.doi.org/10.1007/s10311-018-00839-9.

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Santner, Jakob, Andreas Kreuzeder, Andrea Schnepf, and Walter W. Wenzel. "Numerical Evaluation of Lateral Diffusion Inside Diffusive Gradients in Thin Films Samplers." Environmental Science & Technology 49, no. 10 (April 30, 2015): 6109–16. http://dx.doi.org/10.1021/acs.est.5b00134.

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Sonmez, Osman, and Gary M. Pierzynski. "Assessment of zinc phytoavailability by diffusive gradients in thin films." Environmental Toxicology and Chemistry 24, no. 4 (April 2005): 934–41. http://dx.doi.org/10.1897/04-350r.1.

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Kreuzeder, Andreas, Jakob Santner, Hao Zhang, Thomas Prohaska, and Walter W. Wenzel. "Uncertainty Evaluation of the Diffusive Gradients in Thin Films Technique." Environmental Science & Technology 49, no. 3 (January 26, 2015): 1594–602. http://dx.doi.org/10.1021/es504533e.

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Hill, Benjamin, Jakob Santner, Heide Spiegel, Markus Puschenreiter, and Walter W. Wenzel. "Diffusive gradients in thin films predicts crop response better than calcium-acetate-lactate extraction." Nutrient Cycling in Agroecosystems 121, no. 2-3 (October 7, 2021): 227–40. http://dx.doi.org/10.1007/s10705-021-10173-2.

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AbstractSoil P testing has been widely used to predict crop yields, P uptake, and fertilizer demands in agriculture. Diffusive gradients in thin films (DGT) provides a zero-sink soil P test which mimics diffusion-controlled plant uptake and has previously been found to predict P availability to crops better than conventional quantity-based P tests in highly weathered Australian, though not in European soils. Here we tested the performance of DGT and the Austrian and German standard P quantity test calcium acetate lactate (CAL) to explain the variation of crop yield and P uptake response of winter wheat (Triticum aestivum L.) and spring barley (Hordeum vulgare L.) in long-term P fertilization experiments at four different sites in eastern Austria. Phosphorus extracted with DGT (P-DGT) and CAL (P-CAL) correlated well in similar soils but not across sites with large variation in soil and site properties such as carbonate equivalent and water availability. The predictive power of DGT for barley (R2 = 0.42) and wheat grain yield (R2 = 0.32), and P uptake in wheat grains (R2 = 0.36) was clearly superior to that of the CAL, and less dependent on soil properties. The better performance of DGT compared to the quantity test is consistent with diffusion-limited P uptake in the water-limited cultivated soils of eastern Austria. The critical values of P deficiency derived from the Mitscherlich-type fits for barley and wheat at 80% relative yield are 64.9 and 26.2 µg L−1, respectively, consistent with differential P demands of the crops.
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Ding, Shiming, Yan Wang, Liping Zhang, Lv Xu, Mengdan Gong, and Chaosheng Zhang. "New holder configurations for use in the diffusive gradients in thin films (DGT) technique." RSC Advances 6, no. 91 (2016): 88143–56. http://dx.doi.org/10.1039/c6ra19677b.

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Weng, Hongsheng, Liang Hei, Xu Huang, and Mingxuan Cai. "Application of diffusive gradients in thin-films in sediments and soils." IOP Conference Series: Earth and Environmental Science 675, no. 1 (February 1, 2021): 012025. http://dx.doi.org/10.1088/1755-1315/675/1/012025.

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Mohammadi, Amir, Thomas Corbett, Amanda French, Niklas J. Lehto, John Hadfield, Peter Jarman, Dean Sandwell, Ali Shokri, Louis Schipper, and Adam Hartland. "Application of Diffusive Gradients in Thin Films for Monitoring Groundwater Quality." ACS ES&T Water 2, no. 4 (March 21, 2022): 518–26. http://dx.doi.org/10.1021/acsestwater.1c00279.

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Garmo, Øyvind Aaberg, Oddvar Røyset, Eiliv Steinnes, and Trond Peder Flaten. "Performance Study of Diffusive Gradients in Thin Films for 55 Elements." Analytical Chemistry 75, no. 14 (July 2003): 3573–80. http://dx.doi.org/10.1021/ac026374n.

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Dissertations / Theses on the topic "Diffusive gradients in thin films"

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Altier, Infantes Alexandra. "Diffusive Gradients in Thin-films (DGT) beyond perfect-sink conditions." Doctoral thesis, Universitat de Lleida, 2018. http://hdl.handle.net/10803/585874.

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La presencia d'elements metàl•lics en el medi ambient està fortament influenciada per les activitats antropogèniques entre les que emergeix l'ús de nous materials basats en nanopartícules metàl•liques i òxids metàl•lics. L'especiació d'ions metàl•lics juga un paper fonamental en la determinació de la biodisponibilitat, l’ecotoxicitat i en general en la seva circulació en mitjans naturals. Però la disponibilitat d'elements metàl•lics i les propietats tòxiques o nutritives depenen a mès d’un conjunt de processos fisicoquímics de caràcter dinàmic, on les condicions d'equilibri, malgrat el seu ampli ús, representen només un cas límit. La finalitat d'aquest treball ha estat la mesura dels fluxos de metalls a diferents escales de temps i espai mitjançant la tècnica analítica dinàmica DGT (Diffusive Gradient in Thin-films) així com el desenvolupament de models fisicoquímics adequats per a la interpretació dels resultats. El marc interpretatiu dels resultats DGT s'ha completat amb la inclusió d'efectes escassament descrits en la literatura recent, com ara la influència dels efectes de competició, d’equilibri o de saturació de la resina a més dels fenòmens electrostàtics a baixes forces iòniques. Es presenten expressions aproximades simples per a l'anàlisi d'aquests fenòmens, així com la seva aplicació a sistemes experimentals que permeten observar la seva bondat. Un cop abordat el treball de sistemes simples amb només ions metàl•lics, s'han estudiat sistemes amb un únic lligand i sistemes amb mescles de lligands. Amb aquests sistemes s'ha analitzat fins a quin punt la contribució dels complexos a la disponibilitat depèn de la composició del sistema, tot corroborant que mesures en sistemes amb un únic complex serveixen per predir el comportament de les mescles. A causa de les variacions espacials i temporals que poden patir les concentrations dels ions metàl•lics en aigües naturals, l'última part de l'estudi s'ha centrat en avaluar la capacitat de resposta de la tècnica DGT per mesurar fluctuacions en la concentració. Aquest estudi ha demostrat que a més de proporcionar concentracions mitjanes amb el temps en condicions relativament simples, aquesta tècnica és capaç de determinar concentracions representatives en una àmplia gamma de condicions naturals.
La presencia de elementos metálicos en el medio ambiente está fuertemente influenciada por actividades antropogénicas entre las que emerge el uso de nuevos materiales basados en nanopartículas metálicas y óxidos metálicos. La disponibilidad de elementos metálicos y sus propiedades tóxicas o nutritivas están determinadas por un conjunto de procesos físico-químicos de carácter dinámico, donde la especiación en condiciones de equilibrio, a pesar de su amplio uso, representa sólo un caso límite. La finalidad de este trabajo ha sido la medida de los flujos de metales disponibles a diferentes escalas de tiempo y espacio mediante la técnica analítica dinámica DGT (Diffusive Gradient in Thin-films) así como el desarrollo de modelos fisicoquímicos adecuados para la interpretación de los resultados. El marco interpretativo de los resultados DGT se ha completado con la inclusión de efectos escasamente descritos en la literatura reciente, tales como la influencia de los efectos de competición, equilibrio o saturación de la resina además de la relevancia de los fenómenos electrostáticos a bajas fuerzas iónicas. Se presenta el análisis de estos fenómenos, con expresiones analíticas aproximadas deducidas a partir de la formulación del problema y se aplican a sistemas experimentales para observar la validez de dichas aproximaciones. Una vez abordado el trabajo de sistemas simples con sólo iones metálicos, se han estudiado sistemas con un único ligando y sistemas con mezclas de ligandos. Con estos sistemas se ha analizado hasta qué punto la contribución de los complejos a la disponibilidad depende de la composición del sistema, corroborándose que medidas del grado de labilidad en sistemas con un único complejo pueden predecir el flujo en las mezclas. Se reportan los mecanismos fisicoquímicos que describen la influencia del efecto mezcla sobre el grado de labilidad de un complejo determinado. Debido a las variaciones espaciales y temporales que pueden sufrir los iones metálicos en aguas naturales, la última parte del estudio se ha centrado en evaluar la capacidad de respuesta de la técnica DGT para medir fluctuaciones en la concentración. Este estudio ha demostrado que además de proporcionar concentraciones promediadas con el tiempo en condiciones relativamente simples, esta técnica es capaz de determinar concentraciones representativas en una amplia gama de condiciones naturales.
The presence of heavy metals in the environment is strongly influenced by anthropogenic activities due to the emerging use of new materials based on metallic nanoparticles or metal oxides. The speciation of metal ions plays a fundamental role in the determination of bioavailability, ecotoxicity and in general in its circulation in natural media. The availability of metal ions and their toxic or nutritive properties are determined by a set of physical-chemical processes, where equilibrium conditions, despite its widespread use, only represent a limiting case. The aim of this work was to measure the flux of available metals at different time and space scales through the dynamic analytical technique DGT (Diffusive Gradient in Thin-films). The interpretative framework of the DGT results has also been completed with the inclusion of effects scarcely described in the recent literature, such as the influence of competition, saturation of the resin sites, kinetic effects in the binding of the target analyte to the resin domain or the relevance of electrostatic phenomena at low ionic strengths. Approximate analytical expressions were deduced from the basic formulation and applied to experimental systems to check the agreement with the experimental accumulations. Once the study of simple systems with only metal ions has been addressed, systems with a single ligand or systems with a mixture of complexes have been studied. These systems were analyzed to test if the composition of the system modifies the availability of the complexes. As a conclusion of this work, it was shown that the lability degree of complexes measured in single ligand systems can be used to approximately predict the accumulation in mixtures. A physicochemical explanation of the mechanism by which the lability of a complex changes in a mixture was reported. Since spatial and temporal variations in metal concentrations are common in natural waters, the last part of this study has focused on the assessment of the response capabilities of the DGT technique to measure concentration fluctuations. This study has shown that besides it provides time-weighted average concentrations over time for relatively simple conditions, this technique is able to determine accurate and representative metal concentrations in a wide range of natural conditions.
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Kobayashi, Takahiro. "Development and application of the DGT technique for the measurement of nitrate, ammonia and phosphate in natural waters, sediments and soils." Thesis, Lancaster University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302435.

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Luo, Jun. "Effect of soil dynamics on metal uptake by plants and diffusive gradients in thin-films." Thesis, Lancaster University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.533063.

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Cole, Russell Francis. "Determination of organotin compounds in coastal sediment pore-water by diffusive gradients in thin-films (DGT) technique." Thesis, University of Portsmouth, 2016. https://researchportal.port.ac.uk/portal/en/theses/determination-of-organotin-compounds-in-coastal-sediment-porewater-by-diffusive-gradients-in-thinfilms-dgt-technique(f452f268-d8c7-4ca9-acb3-ffd6fb733f8e).html.

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Organotin compounds still present a high risk to biota in the aquatic environment. Measuring the behaviour of the freely dissolved fractions of these compounds in sediment compartments is challenging, with costly and sensitive analytical techniques required for their measurement. Diffusive gradients in thin-films (DGT) allow for the uptake and pre-concentration of analytes in a binding gel and is used to measure dissolved metals and some organic compounds. The utility of novel silica-bound sorbents (C8, C18, mixed phases) as DGT binding gels for the sequestration of organotins in the marine environment was the primary focus of work in this project. The C8 sorbent showed the optimum performance in the uptake and recovery of organotins across pH, ionic strength and in filtered sea water. It was used subsequently as the binding layer in DGT sediment devices (160 mm × 34 mm) overlaid with a mixed-cellulose ester membrane (0.45 μm) as the single diffusion layer. These were used to investigate pore water mobilisation and concentrations of organotins in coastal sediment cores collected from a contaminated site. Organotins demonstrated a non-sustained uptake scenario, with DGT flux and freely dissolved concentrations in pore water measured to decline at 1 cm depth intervals over deployments of 2-28 days. Using time series, concentrations in pore water at t = 0 were calculated providing empirical pore water depletion curves for sediment cores. Using standard laboratory instrumentation (i.e. gas chromatography-mass spectrometry) low limits of detection were achieved (TBT = 0.4 ng L-1 after 2 weeks of sampling).
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Lindfors, Sarah. "Metal Fractionation in Snowmelt Runoff : A Comparison between Ultrafiltration and Diffusive Gradients in Thin Films (DGT) techniques." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-65018.

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Urban runoff is a non-point pollution source deteriorating water quality of natural watersystems. The composition of urban runoff vary depending on land use, seasonal changes anddifferent surfaces that come into contact with the water. Urban runoff often contain metals andAl, Cd, Cr, Cu, Fe, Ni, Pb and Zn are of particular concern for the environment due to theirpotential toxicity. Metals in runoff can be present in different phases, associated with particles,colloids of different sizes or dissolved in the free phase. The different phases vary in size butalso overlap each other. Information about metal phases and species in runoff is essential tounderstanding metal transport and design runoff treatment systems.Membrane filtration followed by ultrafiltration is an established technique to distinguish theparticulate, colloidal and truly dissolved fractions. However, the “truly dissolved” fraction mayconstitute of the free phase, colloidal phase or both of them since the technique onlydiscriminates by size. Diffusive gradients in thin films (DGT) is a relatively new technique thatmeasures the labile fraction, sometimes referred to as the most bioavailable fraction. The labilefraction includes free metal ions and small complexes available to diffuse through a diffusivelayer under a reasonable period of time. Kinetically inert species are discriminated.The scope of this thesis was to investigate metal fractionation in snowmelt runoff from differenturban surfaces using two techniques, ultrafiltration and DGT. An additional aim was to studythe speciation described by the two techniques in the different types of runoff. Two types ofrunoff were sampled to conduct measurements on. Runoff from well-defined catchments (anindustrial area and a parking lot) and roof runoff from two roofing materials (zinc and coppersheet). In total, four runoff samples were membrane filtrated (pore size 0.45 μm) followed byeither ultrafiltration (delimiting 3 kNMWL) or DGT measurements in the laboratory. Analysisof metals was conducted in all steps and pH, electric conductivity, total suspended solids andtotal organic carbon was measured in the untreated samples.The results show that metal concentrations were generally higher in the catchment runoffcompared to the roof runoff with few exceptions, Cu and Pb from copper roof and Zn from zincroof. Regarding fractionation, the two types of runoff showed similarities when it came tometals mainly bound to particles. The metals that were abundant in several phases showeddifferent fractionations between the catchment runoff and the roof runoff. The metals releasedin roof runoff was to a higher extent found as free ions compared with the catchment runoff. Adiscussion was held about the different metal fractions and treatment possibilities. Comparingthe two techniques, the DGT measurements could be used to further interpret the results fromthe ultrafiltration regarding the colloidal and free phase.
Dagvatten är en diffus föroreningskälla som försämrar vattenkvalitén hos naturliga vattendrag.Samansättningen av föroreningar i dagvatten kan variera beroende på markanvändning,årstidsvariationer och de olika ytor som dagvattnet kommer i kontakt med. Dagvatten innehållerofta metaller och Al, Cd, Cr, Cu, Fe, Ni, Pb och Zn kan vara toxiska för miljön i högakoncentrationer. Metaller i dagvatten kan förekomma i olika faser beroende på om de är bundnamed partiklar, kolloider av olika storlek eller om de är i löst fas. De olika faserna varierar istorlek men överlappar även varandra något. Kunskap om de olika faserna är viktigt förförståelsen om metallernas transportmekanismer och för att kunna designa eller förbättrareningssystem.Membranfiltrering följt av ultrafiltrering är en etablerad teknik för att särskilja partikulärtmaterial, kolloider och den sanna lösta fraktionen. Dock så kan den ”sanna lösta” fraktioneninnehålla antingen den kolloidala fasen, lösta fasen eller båda två eftersom tekniken baseras påstorleksfördelning. DGT (på engelska diffusive gradients in thin films) är en relativt ny tekniksom mäter den labila fraktionen som ibland benämns som den mest biotillgängliga fraktionen.Den labila fraktionen inkluderar fria metalljoner men även små komplex som kan diffunderagenom en diffusionsgel under en rimlig tidsperiod. Species som är kinetisk inerta kommer intemätas.Syftet med detta arbete var att undersöka metallfraktionering i snösmälts-avrinning från olikaurbana ytor genom att använda två tekniker, ultrafiltrering och DGT. Ett delmål var även attgranska de species som beskrevs av de två teknikerna i de olika typerna av dagvatten. Två olikaslags dagvatten samlades in och undersöktes. Dagvatten från väldefinierade avrinningsområden(ett industriområde och en parkeringsplats) och takavrinning från två takmaterial (zink- ochkopparplåtar). Totalt fyra dagvattenprover genomgick membranfiltrering (porstorlek 0,45 μm)följt av antingen ultrafiltrering (avgränsning 3 kNMWL) eller DGT mätningar i laboratoriet.Metallanalyser genomfördes i alla steg och pH, konduktivitet, suspenderade partiklar ochorganiskt kol mättes på det obehandlade proverna.Resultaten visade att de uppmätta metallkoncentrationerna var generellt högre i takavrinningenjämfört med dagvattnet från de hela avrinningsområdena. Dock med några undantag, Cu ochPb från koppartak och Zn från zinktak. När det kom till fraktionering fanns det likheter mellanavrinning från hela områden och från taken beträffande de metaller som till största del varbundna till partiklar. Däremot var det skillnad mellan de olika avrinningstyperna gällandefraktionering av metallerna som förekom i flera av faserna. I takavrinningen fanns det i störreutsträckning metaller som fria joner jämfört med avrinningsområdena. En slutsats var att DGTmätningarna kunde användas till att tolka resultaten från ultrafiltreringen när det gälldekolloidala och fria faserna.
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Bennett, William W. "Development of the Diffusive Gradients in Thin Films Technique for the Measurement of Inorganic Arsenic Speciation in Water and the Investigation of Arsenic Sediment Biogeochemistry." Thesis, Griffith University, 2012. http://hdl.handle.net/10072/365634.

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A novel diffusive gradients in thin films (DGT) technique for the measurement of inorganic arsenic speciation in situ was developed and evaluated. In addition, a diffusive equilibration in thin films (DET) technique was optimized for the high-resolution, colorimetric measurement of iron(II) in sediment porewaters. These techniques were then utilized to investigate processes of arsenic mobilization in sediments and the effect of changing redox conditions on the cycling of arsenic in freshwater and marine sediments. A titanium dioxide-based adsorbent, Metsorb™, was evaluated as a DGT adsorbent for measuring total inorganic arsenic (AsIII and AsV), as well as selenite (SeIV). Performance characteristics such as diffusion coefficients, linear accumulation over time, the effect of pH and ionic strength, and the capacity of the adsorbent were tested and found to be acceptable. The method was also evaluated in the field and found to accurately and precisely measure environmentally relevant arsenic concentrations. The speciation of inorganic arsenic was achieved by developing a second DGT technique that selectively measured AsIII in the presence of AsV. This new technique utilized a mercaptopropylfunctionalized silica gel as a selective adsorbent for AsIII, allowing the speciation of total inorganic arsenic to be calculated by deploying both sampler types simultaneously and calculating the AsV concentration by difference. This new approach to in situ arsenic speciation was successfully evaluated at a variety of pH levels and ionic strengths, and in the challenging matrix of seawater. The newly developed DGT techniques for arsenic speciation were applied to the investigation of arsenic mobility in sediments. To aid in this, a recently described colorimetric DET technique was optimized for the measurement of iron(II) concentrations in sediment porewater. The diffusive gel located at the front of the DGT samplers was utilized as the DET gel for colorimetric analysis of iron(II), enabling co-distributions of these analytes to be measured in situ. The combined DET – DGT approach was applied to freshwater, estuarine and marine sediment mesocosms to investigate the relationship between the reductive dissolution of iron(III) (hydr)oxide minerals and the release of arsenic to sediment porewaters. The effect of induced anoxia and subsequent reoxygenation on arsenic and iron cycling within freshwater and marine sediments was also investigated using sediment mesocosm incubations and the newly developed DET and DGT techniques. These techniques, used in conjunction with sediment mesocosms, proved to be a powerful new approach for the investigation of arsenic biogeochemistry and the mechanisms of arsenic mobilization in the environment.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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Li, Weijia, and n/a. "Development of New Binding Phases for Speciation Measurements of Trace Metals with the Diffusive Gradients in Thin Films Technique." Griffith University. School of Environmental and Applied Science, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040504.150905.

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The recently developed technique of diffusive gradients in thin films (DGT) for speciation measurement of analytes in the environment was further developed through the development of series of new binding phases including poly(acrylamide-co-acrylic acid) copolymer hydrogel (PAM-PAA), poly(acrylamidoglycolic acid-co-acrylamide) (PAAGA-PAM) hydrogel, the Whatman P81 cellulose phosphate ion exchange membrane (P81) and a liquid binding phase of poly(4-styrenesulfonate) (PSS). A new diffusion layer, cellulose dialysis membrane, was also employed for the liquid binding phase DGT. PAM-PAA copolymer hydrogel was prepared by the controlled hydrolysis of polyacrylamide (PAM) in an alkaline solution of 10% sodium hydroxide. The capacity of the copolymer hydrogel to bind various metal ions was tested under a range of uptake conditions. Ions such as Cu2+ and Cd2+ were bound more strongly to the copolymer hydrogel than the competing ions such as Na+, K+, Ca2+ and Mg2+. Metals bound to the copolymer hydrogel can be efficiently eluted in 2 M HNO3 solution (>94%). Application of this new binding material to DGT technique was validated in a synthetic lake water (Windermere, Lake District, UK) with a recovery of 99.0% for Cu2+. PAAGA-PAM hydrogel was prepared by copolymerising 2-acrylamidoglycolic acid with acrylamide. The metal ion binding properties of the hydrogel were characterised for Cu2+, Cd2+ and competing ions under various experimental conditions. The hydrogel was shown to bind Cu2+ and Cd2+ strongly under non-competitive binding conditions, with binding capacities of 5.3 and 5.1 micromol cm-2, respectively. The binding capacity of each metal decreased, under competitive binding conditions (with a range of metal ions present at 17.8 mN), to 1.3 and 0.17 micromol cm-2, respectively, indicating a strong selective binding towards Cu2+. The metal ions were readily recovered (>94%) by eluting with 2 M HNO3. Finally, the copolymer hydrogel was tested as a binding phase with the DGT technique. A linear mass vs. time relationship was observed for Cu2+ in Windermere water with a recovery of close to 100%. The use of a commercially available solid ion exchange membrane (P81) as the binding phase in DGT analysis was demonstrated. P81 is a strong cation exchange membrane. Its performance characteristics as a new binding phase in DGT measurement of Cu2+ and Cd2+ were systematically investigated. Several advantages over the conventional ion exchange resin-embedded hydrogel based binding phases used in DGT were observed. These include: simple preparation, ease of handling, and reusability. The binding phase preferentially binds to transition metal ions rather than competing ions. Within the optimum pH range (pH 4.0 - 9.0), the maximum non-competitive binding capacities of the membrane for Cu2+ and Cd2+ were 3.22 and 3.07 micromol cm-2, respectively. The suitability of the new membrane-based binding phase for DGT applications was validated experimentally. The results demonstrated excellent agreement with theoretically predicted trends. The reusability of this binding phase was also investigated. Application of a liquid binding phase and a dialysis membrane diffusive layer were proposed for the first time. The binding phase was a 0.020 M solution of poly(4-styrenesulfonate) (PSS) polyelectrolyte using a specially designed DGT device. The binding properties of Cd2+, Cu2+, and a range of alkali and alkaline earth metal ions to the PSS solution were characterised. The PSS behaved like a cation exchanger with preferential binding to Cd2+ (6.0 micromole ml-1, log K = 9.0) and Cu2+ (2.5 micromole ml-1, log K = 8.1) under competitive binding conditions. The DGT devices were successfully validated for Cd2+ and Cu2+ in Windermere water. The speciation performance of the solid and liquid binding phases developed in this study was investigated in solutions containing ethylenediaminetetraacetic acid disodium salt (EDTA), humic acid (HA), glucose (GL), dodecylbenzenesulfonic acid (DBS) and tannic acid (TA) with Cu2+ and Cd2+. The ratios of labile metals over total metals were at good agreement with calculated theoretical values using Stability Constants Database. The results indicated that the DGT-labile concentration measured by DGT with these binding phases is essentially free metal ion concentration in the sample. All newly developed DGT binding phases were successfully applied for environmental speciation. The field deployments were carried out in both freshwater and salt-water test sites.
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Li, Weijia. "Development of New Binding Phases for Speciation Measurements of Trace Metals with the Diffusive Gradients in Thin Films Technique." Thesis, Griffith University, 2004. http://hdl.handle.net/10072/367741.

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The recently developed technique of diffusive gradients in thin films (DGT) for speciation measurement of analytes in the environment was further developed through the development of series of new binding phases including poly(acrylamide-co-acrylic acid) copolymer hydrogel (PAM-PAA), poly(acrylamidoglycolic acid-co-acrylamide) (PAAGA-PAM) hydrogel, the Whatman P81 cellulose phosphate ion exchange membrane (P81) and a liquid binding phase of poly(4-styrenesulfonate) (PSS). A new diffusion layer, cellulose dialysis membrane, was also employed for the liquid binding phase DGT. PAM-PAA copolymer hydrogel was prepared by the controlled hydrolysis of polyacrylamide (PAM) in an alkaline solution of 10% sodium hydroxide. The capacity of the copolymer hydrogel to bind various metal ions was tested under a range of uptake conditions. Ions such as Cu2+ and Cd2+ were bound more strongly to the copolymer hydrogel than the competing ions such as Na+, K+, Ca2+ and Mg2+. Metals bound to the copolymer hydrogel can be efficiently eluted in 2 M HNO3 solution (>94%). Application of this new binding material to DGT technique was validated in a synthetic lake water (Windermere, Lake District, UK) with a recovery of 99.0% for Cu2+. PAAGA-PAM hydrogel was prepared by copolymerising 2-acrylamidoglycolic acid with acrylamide. The metal ion binding properties of the hydrogel were characterised for Cu2+, Cd2+ and competing ions under various experimental conditions. The hydrogel was shown to bind Cu2+ and Cd2+ strongly under non-competitive binding conditions, with binding capacities of 5.3 and 5.1 micromol cm-2, respectively. The binding capacity of each metal decreased, under competitive binding conditions (with a range of metal ions present at 17.8 mN), to 1.3 and 0.17 micromol cm-2, respectively, indicating a strong selective binding towards Cu2+. The metal ions were readily recovered (>94%) by eluting with 2 M HNO3. Finally, the copolymer hydrogel was tested as a binding phase with the DGT technique. A linear mass vs. time relationship was observed for Cu2+ in Windermere water with a recovery of close to 100%. The use of a commercially available solid ion exchange membrane (P81) as the binding phase in DGT analysis was demonstrated. P81 is a strong cation exchange membrane. Its performance characteristics as a new binding phase in DGT measurement of Cu2+ and Cd2+ were systematically investigated. Several advantages over the conventional ion exchange resin-embedded hydrogel based binding phases used in DGT were observed. These include: simple preparation, ease of handling, and reusability. The binding phase preferentially binds to transition metal ions rather than competing ions. Within the optimum pH range (pH 4.0 - 9.0), the maximum non-competitive binding capacities of the membrane for Cu2+ and Cd2+ were 3.22 and 3.07 micromol cm-2, respectively. The suitability of the new membrane-based binding phase for DGT applications was validated experimentally. The results demonstrated excellent agreement with theoretically predicted trends. The reusability of this binding phase was also investigated. Application of a liquid binding phase and a dialysis membrane diffusive layer were proposed for the first time. The binding phase was a 0.020 M solution of poly(4-styrenesulfonate) (PSS) polyelectrolyte using a specially designed DGT device. The binding properties of Cd2+, Cu2+, and a range of alkali and alkaline earth metal ions to the PSS solution were characterised. The PSS behaved like a cation exchanger with preferential binding to Cd2+ (6.0 micromole ml-1, log K = 9.0) and Cu2+ (2.5 micromole ml-1, log K = 8.1) under competitive binding conditions. The DGT devices were successfully validated for Cd2+ and Cu2+ in Windermere water. The speciation performance of the solid and liquid binding phases developed in this study was investigated in solutions containing ethylenediaminetetraacetic acid disodium salt (EDTA), humic acid (HA), glucose (GL), dodecylbenzenesulfonic acid (DBS) and tannic acid (TA) with Cu2+ and Cd2+. The ratios of labile metals over total metals were at good agreement with calculated theoretical values using Stability Constants Database. The results indicated that the DGT-labile concentration measured by DGT with these binding phases is essentially free metal ion concentration in the sample. All newly developed DGT binding phases were successfully applied for environmental speciation. The field deployments were carried out in both freshwater and salt-water test sites.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environmental and Applied Science
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Köhler, Sandra. "Bestimmung der Bioverfügbarkeit von Kupfer und Zink in Böden mit der Methode DGT (diffusive gradients in thin films)." Zürich : ETH, Eidgenössische Technische Hochschule Zürich, Institut für terrestrische Ökologie, 2002. http://e-collection.ethbib.ethz.ch/show?type=dipl&nr=102.

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Kane, David. "Evaluating phosphorus availability in soils receiving organic amendment application using the Diffusive Gradients in Thin-films (DGT) technique." Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/8001.

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Phosphorus is a resource in finite supply. Use of organic amendments in agriculture can be a sustainable alternative to inorganic P, provided it can meet crop requirements. However a lack of consistent knowledge of plant P availability following application of organic amendments, limits its potential. Studies suggest chemical extraction procedures, may not reflect plant available P. The Diffusive Gradients in Thin-films (DGT) technique is based on natural diffusion of P via a hydrogel and sorption to a ferrihydrite binding layer; which should accurately represent soil P (CDGT) in a plant available form. The aim of this research was to evaluate changes in soil P availability, following the addition of organic amendments, cattle farmyard manure (FYM), green waste compost (GW), cattle slurry (SLRY) and superphosphate (SP) using Olsen P and DGT. The research included incubation, and glasshouse studies, using ryegrass (Lolium perenne L.). Soils with a history of application of the aforementioned organic amendments were used (Gleadthorpe), as well as a soil deficient in P (Kincraigie). The hypotheses were as follows H1 A build-up of P available by diffusive supply, from historic treatment additions and subsequent availability from fresh treatment additions will be demonstrated by DGT. H2 Historical treatment additions are more important at determining yield and P uptake than fresh additions. H3 DGT can detect changes in P available by diffusive supply following addition of different treatments and subsequently following lysis of microbial cells on a soil deficient in P. H4 DGT will provide a more accurate indication of plant P availability than organic amendments in a soil deficient in P. H5 P measurements using DGT will be lower from organic amendments than superphosphate.H6 DIFS simulations of soil kinetic parameters will provide additional information about how treatments influence P resupply from solid phase to solution following DGT deployment. Cont/d.
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Books on the topic "Diffusive gradients in thin films"

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Davison, William, and Hao Zhang, eds. Diffusive Gradients in Thin-Films for Environmental Measurements. Cambridge: Cambridge University Press, 2016. http://dx.doi.org/10.1017/cbo9781316442654.

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Brown, James L. The thin oil film equation. Moffett Field, Calif: National Aeronautics and Space Administration, Ames Research Center, 1999.

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Davison, William. Diffusive Gradients in Thin-Films for Environmental Measurements. Cambridge University Press, 2016.

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Davison, William. Diffusive Gradients in Thin-Films for Environmental Measurements. Cambridge University Press, 2016.

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Davison, William. Diffusive Gradients in Thin-Films for Environmental Measurements. Cambridge University Press, 2016.

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Book chapters on the topic "Diffusive gradients in thin films"

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Wang, Jin, Liyuan Yang, and Enfeng Liu. "Application of diffusive gradient in thin films in the study of phosphorus mobility at sediment-water interface: A case study of the outlet of Nansi Lake." In Advances in Civil Engineering and Environmental Engineering, Volume 2, 3–7. London: CRC Press, 2023. http://dx.doi.org/10.1201/9781003383031-1.

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Genzel, C. "Problems Related to X-Ray Stress Analysis in Thin Films in the Presence of Gradients and Texture." In Diffraction Analysis of the Microstructure of Materials, 473–503. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-06723-9_18.

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Wohlschlögel, M., W. Baumann, U. Welzel, and Eric J. Mittemeijer. "Mechanical Stress Gradients in Thin Films Analyzed Employing X-Ray Diffraction Measurements at Constant Penetration/Information Depths." In Materials Science Forum, 19–24. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-414-6.19.

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"Determination of arsenic species using the Diffusive Gradients in Thin films (DGT) device." In Understanding the Geological and Medical Interface of Arsenic - As 2012, 452–53. CRC Press, 2012. http://dx.doi.org/10.1201/b12522-164.

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Guan, Dong-Xing. "Diffusive Gradients in Thin-Films (DGT): An Effective and Simple Tool for Assessing Contaminant Bioavailability in Waters, Soils and Sediments." In Encyclopedia of Environmental Health, 111–24. Elsevier, 2019. http://dx.doi.org/10.1016/b978-0-12-409548-9.11403-4.

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"Performance characteristics of diffusive gradients in thin films with a mixed-binding layer gel for the measurement of inorganic arsenic and metals." In Understanding the Geological and Medical Interface of Arsenic - As 2012, 454–56. CRC Press, 2012. http://dx.doi.org/10.1201/b12522-165.

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"Diffusive Equilibration in Thin Films (DET)." In Encyclopedia of Ocean Engineering, 367. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-10-6946-8_300176.

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Aveyard, Bob. "Thin liquid films." In Surfactants, 314–36. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198828600.003.0012.

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The study of soap films, which are symmetrical, has a distinguished history. More recently, other asymmetric liquid films (e.g. pseudo-emulsion films and wetting films on solids) have been widely investigated. The (meta)stability of thin liquid films can be understood in terms of disjoining pressure isotherms, the shapes of which reflect the nature of the films. Film stability in systems with only fluids present can also be considered in terms of both classical and generalized entry coefficients, defined in terms of the various interfacial tensions in the system. Film rupture obviously occurs as a result of dynamic processes. Film drainage (thinning) rate is influenced by surface concentration gradients in the surfactant layers at film surfaces and by the effects of Marangoni flow within the films. To be stable, films need to have elastic properties in order to withstand mechanical perturbations. If the repulsive forces between surfaces become insufficient, hole formation will lead to film rupture.
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"Profiling of fibre texture gradients in thin films by anomalous X-ray diffraction." In Fifth Size Strain Conference. Diffraction Analysis of the Microstructure of Materials, 263–72. Oldenbourg Wissenschaftsverlag, 2008. http://dx.doi.org/10.1524/9783486992564-033.

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MORTAKI, M., B. CHENNI, J. DUCLOS, and M. LEDUC. "The Newton-Raphson and Conjuguate Gradients algorithms for the acoustic characterization of thin films." In Ultrasonics International 93, 827–30. Elsevier, 1993. http://dx.doi.org/10.1016/b978-0-7506-1877-9.50205-5.

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Conference papers on the topic "Diffusive gradients in thin films"

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Hong-Tao Fan, Wu Dandan, and Gao Ze. "The measurement of Sb(III) by diffusive gradients in thin-films with sodium polyacrylate solution as the binding agent in waters." In 2011 International Symposium on Water Resource and Environmental Protection (ISWREP). IEEE, 2011. http://dx.doi.org/10.1109/iswrep.2011.5893559.

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Bartholomeusz, Brian J. "Manifestations Of Through Thickness Thermal Gradients In Laser Irradiated Thin Films." In OE/LASE '89, edited by Gordon R. Knight and Clark N. Kurtz. SPIE, 1989. http://dx.doi.org/10.1117/12.952759.

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Kim, Dongchoul, and Wei Lu. "Interface Instability and Morphology Evolution of Thin Films Induced by Electrostatic Interaction." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-14954.

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Experiments have shown that a thin polymer film subjected to an electrostatic field may lose stability at the polymer-air interface, leading to uniform self-organized pillars emerging out of the film surface. This paper presents a three dimensional model to account for this behavior. Attention is focused on a fully nonlinear evolution simulation to reveal the dynamic process from an early perturbation to late structure formation. Energetic components involving the interface energy and dielectric effect, and kinetics of coupled viscous flow and diffusion are incorporated into a phase field framework. The semi-implicit Fourier spectral method and preconditioned biconjugate-gradient method are applied for high efficiency and numerical stability. The simulations reveal rich dynamics of the pattern formation process, and show that the kinetic constraint of the substrate can essentially limit structure coarsening. The pillar size is insensitive to the film thickness while the distance between pillars and the growth rate are significantly affected. The study also suggests an approach to control structural formation in thin films with a designed electric field.
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Chen, J. K., J. E. Beraun, and D. Y. Tzou. "A Dual-Phase-Lag Diffusion Model for Predicting Thin Film Growth." In ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0928.

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Abstract A dual-phase-lag diffusion (DPLD) model, which extends Fick’s law by including two lagging times, τj for the mass flux vector and τρ for the density gradient, is developed to predict thin film growth. Depending upon the phase lag ratio τρ/τj, the proposed model uniquely characterizes four types of growth kinetics as reported in the literature. The model validation with the experimental data of silicon oxidation and Hg1-xCdxTe film deposition demonstrates that the DPLD model captures the anomalous behavior of thin film growth from the very beginning of the process to relatively long times very well.
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Yamada, Toru, Sina Hamian, Keunhan Park, Yutaka Asako, and Mohammad Faghri. "Diffusive-Ballistic Heat Transport in Thin Films Using Energy Conserving Dissipative Particle Dynamics." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-89641.

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Diffusive-ballistic heat transport in thin films was simulated using energy conserving dissipative particle dynamics (DPDe). The solution domain was considered to be two-dimensional and DPD particles were distributed in the solution domain uniformly under constant temperature boundary conditions at the top and bottom walls and periodic boundary at the side walls. The effects of phonon mean free path was incorporated by its relation to the cutoff radius of energy interaction. This cutoff radius was obtained based on Knudsen number using the existing phonon-boundary scattering models. The simulations for 0.1 < Kn < 10 were conducted with the different modifications of the cutoff radius. The results were presented in form of temperature profile across the thin film and were compared with the semi-analytical solution of the equation of phonon radiative transport (EPRT). The discrepancy of the simulations without the phonon mean free path modification was less than 15% with EPRT. Good agreement with EPRT to within 5% was obtained when the phonon-boundary scattering effects were included.
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Park, Wontae, John E. Anthony, and William S. Wong. "Formation of highly crystalline organic semiconductor thin films by inkjet printed thickness gradients." In Organic and Hybrid Field-Effect Transistors XIX, edited by Oana D. Jurchescu and Iain McCulloch. SPIE, 2020. http://dx.doi.org/10.1117/12.2568099.

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Sutta, Pavol. "Lattice stress gradients in zinc oxide thin films and their influence on the preferentially oriented growth of the films." In International Conference on Solid State Crystals 2000, edited by Jaroslaw Rutkowski, Jakub Wenus, and Leszek Kubiak. SPIE, 2001. http://dx.doi.org/10.1117/12.425445.

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Xu, Mingtian, and Lin Cheng. "Ballistic-Diffusive Heat Conduction Model." In 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-22243.

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In the present work, the heat flux and high order fluxes as well as their time derivatives are taken as independent variables and a new type of extended irreversible thermodynamics is developed. In the framework of this extended irreversible thermodynamics, the size dependence of the effective conductivity is investigated and a generalized single phase lagging heat conduction model including the size effect is established. Theoretically, it covers the diffusive to ballistic regime of heat conduction. The comparison with the experimental and theoretical results of silicon nanowires and thin films shows a good agreement in nano-scale regime.
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Lin, Hao, Brian D. Storey, and Juan G. Santiago. "A Depth-Averaged Model for Electrokinetic Flows in a Thin Microchannel Geometry." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61017.

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We have developed a generalized electrokinetic model suitable for the study of microchannel flows with conductivity gradients and shallow channel depths. An asymptotic analysis was performed with channel depth-to-width ratio as the smallness parameter, and three dimensional transport equations are reduced to a set to depth-averaged equations governing flow dynamics in the streamwise-spanwise plane of a shallow channel. The momentum equation uses a Darcy-Brinkman-Forchheimer type formulation, and the convective-diffusive transport of the conductivity field in the depth direction manifests itself as a dispersion effect on in-plane motion. Accuracy of the model was assessed by comparing the numerical results with direct numerical simulations. These depth-averaged equations provide the accuracy of three-dimensional modeling with a convenient quasi-two-dimensional equation set applicable to a fairly wide class of microfluidic devices.
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Lee, Chun-I., Shiqah-Ping Jung, Kan-Lin Hsueh, Chi-Chang Chen, and Wen-Chen Chang. "Effect of Porosity Gradient in Gas Diffusion Layer on Cell Performance With Thin-Film Agglomerate Model in Cathode Catalyst Layer of a PEM Fuel Cell." 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/fuelcell2011-54838.

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A one-dimensional, steady-state, two-phase, isothermal numerical simulations were performed to investigate the effect on cell performance of a PEM fuel cell under non-uniform porosity of gas diffusion layer. In the simulation, the non-uniform porosity of gas diffusion layer was taken into account to analyze the transport phenomena of water flooding and mass transport in the gas diffusion layer. The porosity of the gas diffusion layer is treated as a linear function. Furthermore, the structure of the catalyst layer is considered to be a cylindrical thin-film agglomerate. Regarding the distribution analysis of liquid water saturation, oxygen concentration and water concentration depend on the porosity of gas diffusion layer. In the simulation, the εCG and εGC represent the porosity of the interfaces between the channel and gas diffusion layer and the gas diffusion layer and the catalyst layer, respectively. The simulation results indicate that when the (εCG, εGC) = (0.8, 0.4), higher liquid water saturation appears in the gas diffusion layer and the catalyst layer. On the contrary, when the (εCG, εGC) = (0.4, 0.4), lower liquid water saturation appears. Once the liquid water produced by the electrochemical reaction and condensate of vapor water may accumulate in the open pores of the gas diffusion layer and reduced the oxygen transport to the catalyst sites. This research attempts to use a thin-film agglomerate model, which analyze the significant transport phenomena of water flooding and mass transport under linear porosity gradient of gas diffusion layer in the cathode of a PEM fuel cell.
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