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Thomaz Augusto Guisard Restivo

Bio: Thomaz Augusto Guisard Restivo is an academic researcher from University of São Paulo. The author has contributed to research in topics: Sintering & Cermet. The author has an hindex of 9, co-authored 27 publications receiving 202 citations.
Topics: Sintering, Cermet, Microstructure, Pellets, Ceramic

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors investigated how the testing conditions such as specimen coating, laser power and pulse duration, base line adoption, heat losses correction methods, and specimen thickness, may affect the thermal diffusivity measurements of some ceramic materials using the laser flash technique.

25 citations

Journal ArticleDOI
TL;DR: In this paper, the reduction kinetics of synthetic zinc ferrite by gases containing hydrogen and carbon monoxide were examined via forced stepwise isothermal analysis at temperatures ranging from 500 to 950°C.
Abstract: Solid waste generation is one of the main problems in the steelmaking process. One of the most problematic waste products is the electric arc furnace dust, which is a by-product rich in iron and zinc and is present as zincite (zinc oxide) or franklinite (zinc ferrite). This work focuses on the reduction kinetics of synthetic zinc ferrite by gases containing hydrogen and carbon monoxide. This process was examined via forced stepwise isothermal analysis. The test was conducted at temperatures ranging from 500 to 950 °C. Reduction of zinc was accomplished using a mixture of hydrogen and carbon monoxide in order to simulate reformed natural gas. The results indicated that reduction of zinc ferrite occurred in two stages (550–750 °C and 800–900 °C). The first stage was characterized by iron oxide reduction, where a mix control between nucleation and diffusion was determined. The apparent activation energy obtained was 71.5 kJ mol−1. The second stage was characterized by zinc oxide reduction, where the controlling mechanism was identified as a mixed control between diffusion and phase boundary reaction. The apparent activation energy was 135.5 kJ mol−1. The formation of a dense layer of metallic iron around the unreacted core may have caused the apparent activation energy to increase.

24 citations

Journal ArticleDOI
TL;DR: In this article, the performance of U-7.5Nb-2.5Zr and U-10Mo alloys were characterized by mechanical and thermal analyses for comparison of their behavior under deformation and heat-treatment.

21 citations

Journal ArticleDOI
TL;DR: In this article, a process based on high energy milling (or mechanical alloying) of metallic Ni and YSZ at 40% Ni composition for the preparation of solid oxide fuel cell anode material is described.

19 citations

Journal ArticleDOI
TL;DR: In this article, a forced stepwise isothermal analysis method was used to study the kinetic reaction of electric arc furnace dust pellets using a reducing gas simulating the reformed natural gas.
Abstract: The purpose of this paper is to study the kinetic reaction of electric arc furnace dust pellets using a reducing gas simulating the reformed natural gas. The kinetic investigation was accomplished via forced stepwise isothermal analysis method. The tests were programmed in the range of 500–1000 °C. It was used a reducing gas contained 25 % of CO and 75 % of H2. X-ray patterns were analyzed in order to understand the reduction process. The results show the reduction of electric arc furnace dust pellet occurs in three steps. At 550–650 °C, the zinc ferrite is reduced to magnetite and zinc oxide, followed by the reduction of magnetite to wustite. Carbon deposition on the pellet surface was detected in this step, which impairs the kinetic analysis. In the range of 700–800 °C, wustite is reduced to iron. It was determined a mixed control between nucleation and diffusion with E a of 89.2 kJ mol−1. At 850–950 °C, the main reaction is zinc oxide reduction to gaseous zinc. However, wustite reduction is also observed. The E a of 135.5 kJ mol−1 with a mixed control between diffusion and chemical reaction was detected.

18 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the use of TiO2 photocatalysis for water and waste treatment, treating contaminants of emerging concern (CECs), pesticides, endocrine disrupters (EDs) and bacteria using both UV and visible light irradiations is discussed.
Abstract: Advanced Oxidation technologies (AOTs) are gaining attention as an effective waste water treatment methodology capable of degrading diverse spectrum of recalcitrant organic contaminants and microbes. Undoubtedly, photocatalysis is a promising AOT to alleviate the problem of water pollution. Despite recent research into other photocatalysts (e.g. ZnO, ZnS, Semiconductor-Graphene composites, perovskites, MoS2, WO3 and Fe2O3), titanium dioxide (TiO2) remains the most popular photocatalyst due to its low cost, nontoxicity and high oxidising ability. Moreover, titania photocatalysts can easily be immobilized on various surfaces and be scaled up for large scale water treatment. The current review aims to highlight recent advancements in photocatalytic AOTs with main emphasis on TiO2 photocatalysis. This review also discusses the use of TiO2 photocatalysis for water and waste treatment, treating contaminants of emerging concern (CECs), pesticides, endocrine disrupters (EDs) and bacteria using both UV and visible light irradiations. It was concluded that with efficient photoreactor configuration and further studies on the photocatalyst regeneration, TiO2 photocatalysis is a viable option for the reclamation of agricultural/irrigational waste water. Novel doped photocatalysts such as ZnS-CuS-CdS, carbon spheres/CdS, g-C3N4-Au-CdS, ZnS-WS2-CdS, C3N4-CdS and Pd-Cr2O3-CdS have also been discussed. Finally, the advances in the actively studied metal organic framework based photocatalysts that are emerging as effective alternate for metal oxide based photocatalysts is also discussed in detail.

488 citations

Book ChapterDOI
01 Jan 1987
TL;DR: In this article, the authors presented a theory of liquid alloys and assembled all the necessary tools for the ab initio construction of an alloy phase diagram, which they used to construct a phase diagram.
Abstract: With the presentation of a theory of liquid alloys, we have now assembled all the necessary tools for the ab initio construction of an alloy phase diagram.

417 citations

Journal ArticleDOI
TL;DR: The theoretical basis behind carbon and sulfur poisoning is studied, before examining the strategies toward carbon and sulphur tolerance used so far in the SOFC literature, and the more extensive relevant heterogeneous catalysis literature is studied for strategies and materials which could be incorporated intocarbon and sulfur tolerant fuel cells.
Abstract: Solid oxide fuel cells (SOFCs) are a rapidly emerging energy technology for a low carbon world, providing high efficiency, potential to use carbonaceous fuels, and compatibility with carbon capture and storage. However, current state-of-the-art materials have low tolerance to sulfur, a common contaminant of many fuels, and are vulnerable to deactivation due to carbon deposition when using carbon-containing compounds. In this review, we first study the theoretical basis behind carbon and sulfur poisoning, before examining the strategies toward carbon and sulfur tolerance used so far in the SOFC literature. We then study the more extensive relevant heterogeneous catalysis literature for strategies and materials which could be incorporated into carbon and sulfur tolerant fuel cells.

220 citations

Journal ArticleDOI
TL;DR: In this article, a fuel plate system composed of solid U-10Mo fuel meat, a zirconium diffusion barrier, and Al6061 cladding was selected for development.

132 citations

Journal ArticleDOI
TL;DR: In this paper, the authors examined the impact of increasing concentrations of benzoic acid (1,´:´0, 1´:`1´0´1, 1'':´1´1'' 1´´4´ 1´8´ 8 molar ratio on the anatase phase transition in pure synthetic titanium dioxide.
Abstract: In pure synthetic titanium dioxide, the anatase to rutile phase transition usually occurs between the temperatures of 600 °C and 700 °C. The phase transition temperature can be altered by various methods, including modifying the precursor or by adding dopant or modifier to the TiO2 sample. In an attempt to investigate the phase transition using aromatic carboxylic acids, the current study examines the impact of increasing concentrations of benzoic acid (1 : 0, 1 : 1, 1 : 4 and 1 : 8 molar ratio TiO2 : benzoic acid) on anatase to rutile transition. The samples were characterised using Raman spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) studies. At 500 °C, all samples contained only anatase. At 600 °C, the 1 : 1, 1 : 4 and 1 : 8 samples contain only anatase and the control (which contains no modifier) was a mixture of 27% anatase and 73% rutile. At 700 °C, the 1 : 1 molar ratio sample contained 50% anatase/rutile, 1 : 4 and 1 : 8 molar ratio samples were observed to have a majority of anatase, 76% and 71% respectively. When the temperature was increased to 800 °C, the sample with the 1 : 4 molar ratio contained 10% anatase and at the same temperature the 1 : 8 ratio sample contained 7% anatase; the remaining samples (1 : 0 and 1 : 1) at this temperature contained only rutile. These results show that there is a significant % anatase still present when the doped samples were calcined to 700 °C when compared with the control (100% rutile). There are small amounts of the anatase phase in the 1 : 4 and 1 : 8 samples at 800 °C. Therefore, benzoic acid has induced a delay in the rutile formation.

97 citations