4 resultados para COUNTER ELECTRODES

em Digital Commons at Florida International University


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Synthesis and functionalization of large-area graphene and its structural, electrical and electrochemical properties has been investigated. First, the graphene films, grown by thermal chemical vapor deposition (CVD), contain three to five atomic layers of graphene, as confirmed by Raman spectroscopy and high-resolution transmission electron microscopy. Furthermore, the graphene film is treated with CF4 reactive-ion plasma to dope fluorine ions into graphene lattice as confirmed by X-ray photoelectron spectroscopy (XPS) and UV-photoemission spectroscopy (UPS). Electrochemical characterization reveals that the catalytic activity of graphene for iodine reduction enhanced with increasing plasma treatment time, which is attributed to increase in catalytic sites of graphene for charge transfer. The fluorinated graphene is characterized as a counter-electrode (CE) in a dye-sensitized solar cell (DSSC) which shows ~ 2.56% photon to electron conversion efficiency with ~11 mAcm−2 current density. Second, the large scale graphene film is covalently functionalized with HNO3 for high efficiency electro-catalytic electrode for DSSC. The XPS and UPS confirm the covalent attachment of C-OH, C(O)OH and NO3- moieties with carbon atoms through sp2-sp3 hybridization and Fermi level shift of graphene occurs under different doping concentrations, respectively. Finally, CoS-implanted graphene (G-CoS) film was prepared using CVD followed by SILAR method. The G-CoS electro-catalytic electrodes are characterized in a DSSC CE and is found to be highly electro-catalytic towards iodine reduction with low charge transfer resistance (Rct ~5.05 Ωcm 2) and high exchange current density (J0~2.50 mAcm -2). The improved performance compared to the pristine graphene is attributed to the increased number of active catalytic sites of G-CoS and highly conducting path of graphene. We also studied the synthesis and characterization of graphene-carbon nanotube (CNT) hybrid film consisting of graphene supported by vertical CNTs on a Si substrate. The hybrid film is inverted and transferred to flexible substrates for its application in flexible electronics, demonstrating a distinguishable variation of electrical conductivity for both tension and compression. Furthermore, both turn-on field and total emission current was found to depend strongly on the bending radius of the film and were found to vary in ranges of 0.8 - 3.1 V/μm and 4.2 - 0.4 mA, respectively.

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This dissertation analyzes a variety of religious texts such as catechisms, confession manuals, ecclesiastical legislation, saints' lives, and sermons to determine the definitions of orthodoxy held by the Spanish clergy and the origins of such visions. The conclusion posited by this research was that there was a definite continuity between the process of Catholic reform in Spain and the process of Catholic expansion into the New World in that the objectives and concerns of the Spanish clergy in Europe and the New World were very similar. This dissertation also analyzes sources that predated the Council of Trent and demonstrates that within the Iberian context the Council of Trent cannot be used as a starting date for the attempts at Catholic reform. In essence, this work concludes the Spanish clergy's activities were influenced by humanist concepts of models and model behaviour which is reflected in their attempt to form model Catholics in Spain and the New World and in their impulse to produce written texts as standards. ^

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This dissertation examined the effect of United States counter-drug policy on nationalism in small states, focusing on Jamaica and Trinidad and Tobago. The states were selected for their roles and geostrategic importance in the illegal drug trade; Jamaica being the largest drug producing country in the Anglophone Caribbean and having strong links to the trade of Colombian cocaine, and Trinidad being a mere seven miles from the South American coast. Since U.S. counterdrug policies have frequently been viewed in the region as imperialistic, this dovetails into ideas on the perceptions of smallness and powerlessness of Caribbean nations. Hence, U.S. drug policies affect every vulnerability faced by the Caribbean, individually and collectively. Thus, U.S. drug policy was deemed the most appropriate independent variable, with nationalism as the dependent variable. In both countries four Focus Groups and one Delphi Study were conducted resulting in a total of 60 participants. Focus Group participants, recruited from the general population, were asked about their perception of the illegal drug trade in the country and the policies their government had created. They were also asked their perception on how deeply involved the U.S. was in the creation of these policies and their opinions on whether this involvement was positive or negative. The Delphi Study participants were experts in the field of local drug policies and also gave their interpretations of the role the U.S. played in local policy creation. Coupled with this data, content analysis was conducted on various newspaper articles, press releases, and speeches made regarding the topic. In comparing both countries, it was found that there is a disconnect between government actions and the knowledge and perceptions of the general public. In Trinidad and Tobago this disconnect was more apparent given the lack of awareness of local drug policies and the utter lack of faith in government solutions. The emerging conclusion was that the impact of U.S. drug policy on nationalism was more visible in Trinidad and Tobago where there was a weaker civil society-government relationship, while the impact on nationalism was more obscure in Jamaica, which had a stronger civil-society government relationship.

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Should the radical Left interpret the Nolans' Interstellar as a tribute to (neo)liberal expansionism or should we view it as a cautionary tale about a future that is just around the corner, which won't be solved by worm holes or time travel? This review takes the latter position against the recent Jacobin review, which argues the former. Here, I show that Interstellar can be productively reinterpreted as a film about a series of things that will NOT save us from our-late-capitalist-selves.