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Hidrotalcitas de Ni-Mg-Al como precursores de catalisadores para produção de gás de síntese a partir de biogás
(Universidade Federal de São Carlos, 2010-07-29) Pedrotti, Wagner; Assaf, José Mansur; https://lattes.cnpq.br/9563312407691130; https://lattes.cnpq.br/2443047062730235
Catalysts obtained by thermal decomposition of the precursors with hydrotalcite-like structure [Mg1-xAlx (OH)2]x+ [CO3]x/n. mH2O and [Ni1-x Mg1-xAlx (OH)2]x+ [CO3]x/n. mH2O were prepared, characterized and tested in the reactions of dry and oxidative reforming of methane. The precursors were modified with the addition of nickel during the precipitation or by impregnation, in order to increase the thermal stability and dispersion of the active metal and the resistance against carbon deposition during the reaction. The catalyst precursors were characterized by X-ray diffraction, thermal and gravimetric analysis, atomic emission spectroscopy, surface area determination (BET method) and temperature programmed reduction. The results indicated that the precipitation method led the formation of the hydrotalcite-type structure and that the variation in the calcination temperature resulted in mixed oxides with the desired structure: at 650 °C the mixed oxides were formed, but when the calcination temperature was increased to 850 °C these oxides had become more stable. It was observed in the catalytic experiments that the addition of different amounts of magnesium influenced the activity and stability of the oxides, when compared with samples that contained only Ni/Al. The mixed oxide with composition 12.67% Ni-Mg1,35/Al was the more active and resistant to deactivation during the reaction.
Estágios imaturos de Lepidoptera e parasitoides associados, em fragmento de mata semidecidual em São Carlos, Estado de São Paulo
(Universidade Federal de São Carlos, 2010-07-29) Iemma, Luis Gustavo Rodrigues; Dias Filho, Manoel Martins; https://lattes.cnpq.br/1346547036069954; https://lattes.cnpq.br/1043228491783390
A semidecidual forest fragment located in Parque Eco-Esportivo Damha, São Carlos, SP, was studied. The purpose was to sample the diversity of Lepidoptera larvae, their host plants and associated parasitoids. Five different plant species were sampled during 13 months using an entomological umbrella; 266 larvae belonging to 11 families and 26 genera were obtained. The most abundant family was Geometridae, with 32.81% of total amount, followed by Nymphalidae and Gelechiidae. The most abundant genus was Eois (Geometridae) with 28.20% of total larvae amount. The major occurrence of larvae was between the end of raining period and the beginning of the dry period. Using the saturation curve is observed that the survey was not sufficient to sample the real diversity of larvae of this forest fragment. During the work, 10% of larvae were parasitized and a total of 907 parasitoids emerged from different hosts, all koinobionts. Tachinidae was the most frequent parasitoid registered and occurred on Quadrus sp.; The most abundant parasitoid in number of specimens was Copidosoma sp. Polyembrionic parasitoid, attended by 787 found on Plusiinae (Noctuidae).
Desenvolvimento de um fluorímetro microcontrolado para determinação de clorofila a em águas superficiais
(Universidade Federal de São Carlos, 2010-07-29) Guerreiro, Thiago Brito; Faria, Ronaldo Censi; https://lattes.cnpq.br/8659496864305621; https://lattes.cnpq.br/4678967713981107
In this work a portable fluorimeter was developed and used for determination of chlorophyll a in water samples. The instrument was constructed using the following components: a microcontroller (PIC18F4550), two LEDs as light source, a multichannel photodiode (TCS-230) as detector and a digital display. LEDs with maximum emission at 405 and 760 nm were used. The detector is equipped with three internal optical filters inside with maximum sensitivity at 480, 540 and 690 nm besides the possible use without the optical filter with high sensitivity in the visible spectral region with maximum sensitivity at 680 nm. The microcontroller works as central processing unit controlling all components of the instrument by a program previously recorded in its memory eliminating the need of a microcomputer. The fluorimeter was calibrated using standard solutions of fluorescein and rhodamine 6G in HCl 1.0 x 10-5 mol L-1 and performance was compared with a commercial spectrofluorimeter, and the results are in agreement at a confidence level of 95%. A linear response range for fluorescein was obtained between 0.5 and 100.0 x 10-6 mol L-1 and a correlation coefficient of 0.996 and for rhodamine 6G a linear response range between 0.2 and 10.0 x 10-6 mol L-1 was obtained and a correlation coefficient of 0.989. The fluorimeter was used for determination of chlorophyll a in water samples and blue algae culture medium. The results were compared with a spetrophotometric method and were in agreement at a confidence level of 95%. A linear range of between 2.5 and 1333.6 x 10-6 g L-1 for chlorophyll a was obtained with a correlation coefficient of 0.995. The concentration range attend the requirements of CONAMA resolution n° 357 that classifies the water quality covering the concentrations of 10.0, 30.0 and 60.0 x 10-6 g L-1 for different classes of water. The fluorimeter is inexpensive, easy to use shows, low power consumption allowing the feed with batteries, small size (10 cm x 20 cm x 15 cm) and with weight of 0.76 kg. The fluorimeter can be used to determine species with excitation at 405 and or 476 nm and emission across the visible range with excellent performance.