Effect of Ag nanoparticles on the radiative properties of tellurite glasses doped with Er3+, Yb3+ and Tm3+ ions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Electrical conductivity of Ag-Na ion exchanged soda-lime glass

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Acetylene plasma polymer treated by atmospheric dielectric barrier discharge

Plasma polymer films are very attractive for industrial applications in several sectors such as in the electronic, mechanic, biomedic, coating and others, due to its good adhesion, being insoluble in mild acids and bases and having a high crosslinking structure. This work reports the physical, structural, and surface properties of the polymer obtained from an acetylene plasma polymerization technique and treated by dielectric barrier discharge (DBD). The film was deposited in a reactor supplied by a radio-frequency power source at low pressure. After deposition, the nanofilms were treated in a DBD plasma reactor operating in air. The treatment times varied from 1 to 5 min. The analysis of molecular structure of the samples was investigated by FTIR spectroscopy, showing absorption bands in 3480, 2930, 1720, 1450 and 1380 cm(-1). The water contact-angle was investigated by goniometric technique and presented values from 5 to 65 degrees. The aging effect of these films was also studied. The alteration in the films surface morphology was assessed by an atomic force microscopy (AFM) which indicated that the roughness increased from 60 nm to 160 nm as a result of the DBD treatment. The refractive index of the samples presented values near 1.7, measured by UV-Visible spectroscopy. (C) 2014 Elsevier Ltd. All rights reserved.

Avaliação do efeito do tratamento com surfactante químico e Pseudomonas aeruginosa LBI na toxicidade de solo contaminado com óleo lubrificante usado

Petroleum and its subproducts are considered a treat for the environmental quality because of the many environmental accidents that may occur during exploitation, transport and storage. A common remediation technique used in the contaminated areas is based on the use of surfactants, mainly the chemical ones, because they have low production costs. In the other hand, some microorganisms have indicate capacities of producing surfactants that emulsify substances and as result, offer a bigger contact surface for the microbiota degradation. This biossurfactants stand out in comparison with the chemical surfactants because they present lower micelar concentration values, are more tolerant for temperature and pH variation, because they are biodegradable, have low toxicity, higher emulsification and hydrocarbon solubilization index. In this way, after the surfactant application, a toxicity evaluation have to be made to identify the treatment effects. In soil, the activity of some microbial enzymes can show the environmental behavior of the contaminant under different treatment conditions. Dehydrogenase is one example of those enzymes that can demonstrate indirectly the effect of the pollutant on the soil microorganisms. The aim of this paper was to evaluate the toxicity after the addition of a surfactant and/or Pseudomonas aeruginosa LBI in soil contaminated by a mineral automotive lubricant. The previous mentioned bacteria are a potential biossurfactant (rhamnolipid) producer. In order to evaluate the toxicity, the dehydrogenase test was run. In this test, trifeniltetrazolium compound (TTC) after utilized as an electron acceptor, turns into trifenil formazan (TPF), that can be indirectly quantified using the absorbance measured by the spectrophotometer UV-visible. In this way, it was possible to quantify the dehydrogenase activity from the contaminated soil samples... (Complete abstract click electronic access below)

Moderating effect of ammonia on particle growth and stability of quasi-monodisperse silver nanoparticles synthesized by the Turkevich method

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Transmission enhancement in chalco-halide glasses for multiband applications

The potential of clear Ga2S3-GeS2-CsCl based sulfide glasses transparent up to 11.5 μm to be used as new optical material for multispectral applications has been investigated. The addition of large amount of chlorine ions – above 40 mol.% of CsCl – into the chalcogenide vitreous network in order to produce colorless glasses results in a drastic increase of their water contamination. We report for the first time, to the best of our knowledge, the purification of cesium chloride CsCl by dynamic distillations under vacuum in order to reduce water and hydroxyl group contamination before complete melting of the glass. Besides, sulfur purification by dynamic and static distillations was also performed in the implemented method. The obtained glasses were then characterized by UV-visible and infrared (FTIR) spectroscopies, by electron probe microanalysis (EPMA), thermal analysis (DSC), and their refractive indices in the visible and near infrared ranges were also measured. A large improvement of the glass transmission spectrum has been achieved with an estimated reduction of about 45 times of the OH and H2O content and 60 times of the SH content. The glass thermal molding ability and chemical durability with and without protective coating have been tested to probe their potential for fabrication of complex optics.

Formação e crescimento do óxido de zinco e óxido de zinco dopado com cobre

Pós-graduação em Química - IQ

Enhanced photoelectrocatalytic degradation of an acid dye with boron-doped TiO2 nanotube anodes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Electrical and electrochemical measurements in nanostructured films of polythiophene derivatives

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Photoelectrochemical reduction of CO2 on Cu/Cu2O films: Product distribution and pH effects

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Entrapment characteristics of hydrosoluble vitamins loaded into chitosan and N,N,N-trimethyl chitosan nanoparticles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Characteristics of PbO-BiO1.5-GaO1.5 glasses melted in SnO2 crucibles

PbO-BiO 1.5-GaO 1.5-based glasses are good candidates for optical applications, because of some of their interesting characteristics, such as high refraction indices and high transmission in the ultraviolet (UV), visible (VIS), and infrared (IR) regions. A limited stage in the processing of these glasses is the corrosion that is caused by the melt in all currently used conventional crucibles, such as noble metals (platinum or gold) and Al 2O 3. The absorption of crucible material by the glass composition may reduce the transmission level, the cutoff in the UV-VIS, and IR regions, and the thermal stability. In this study, a SnO 2 crucible has been tested for PbO-BiO 1.5-GaO 1.5 molten glass. Optical and thermal analyses show, in some cases, advantages over the use of platinum and Al 2O 3 crucibles. A visible cutoff value of 474 nm has been measured, and a longer melting time (850°C for 4 h) results in a significant reduction of the O-H absorption band at 3.2 μm.

Synthesis, characterization and thermal behavior of heterobimetallic carbonyl compounds of the type [W(CO)(4)(bipy)(CuX)] (X=Cl, N-3, ClO4 and BF4)

Four new heterobimetallic metal carbonyls were synthesized by the reaction of [W(CO)4(bipy)] (1) with copper(I) compounds leading to species with the general formula [W(CO)4(bipy)(CuX)] (X = Cl, N3, ClO4, BF4) (2-5). The metal carbonyl compounds were characterized by elemental analysis, infrared and UV -visible electronic spectroscopy and thermogravimetric analysis. The IR data for 2-5 show carbonyl stretching band patterns similar to compound 1 ; ie they exhibit the same number of bands. The UV - vis results show a dissociation reaction generating the starting compound 1 and CuX as consequence of a weak interaction between 1 and CuX. Thermal decomposition mechanisms as well as the thermal stability are influenced by the CuX fragments. The thermal stability decreases in the order [W(CO)4(bipy)] > [W(CO)4(bipy)(CuCl)] > [W(CO)4(bipy) (CuBF4)]. The X-ray results show the formation of WO3, CuWO4, Cu2O and CuO as final decomposition products.

Avaliação da termociclagem sobre a estabilidade de cor de diferentes matizes de resina composta

The objective was to evaluate the effect of thermocycling on the color variation of three different composite resins . We studied was Resin Enamel on 3 levels : ( Esthetic X , Opallis and Venus ) ; Resin Dentin in three levels : ( Esthetic X , Opallis and Venus ) and Thermocycling on level 1 : ( 3,000 cycles ) ; variable was the change of color gauged by spectrophotometry . 60 specimens , subdivided into 6 groups were made : GI - Esthetic X Enamel ; GII - Esthetic X dentin ; GIII - Opallis Enamel ; GIV - Opallis dentin ; GV - Enamel and GVI Venus - Venus dentin . The specimens were prepared with a matrix to standardize samples . The inserts of incrementally resins and polymerized with a halogen light Ultralux unit ( Dabi Atlante , Brazil ) with a power of 450mW / cm ² . After fabrication , underwent color reading with a UV Visible Spectrophotometer reflection , UV -2450 ( Shimadzu , Kyoto , Japan ) , with the changes calculated by the system CIE L * a * b * . Then isolates were stored in artificial saliva at 35 ° C ± 2 ° C during 3 months containers being subjected to the effects of thermal cycling for 3000 cycles over the range of 5C to 55C . Again subjected to chromatic evaluation. For the analysis of the results of color change of the studied resins was applied ANOVA two factors at 5 % . The results showed a statistically equal resins enamel GI and GV ( p = 0.79 ) ; the same was not observed for GI and G III resins , where the color change was higher for resin G III ( p = 0.0000002 ) . The same was observed between G III and GV , where the resin enamel G III showed a statistically superior to the color change ( p = 0.0000005 ) Average . Resins to dentin was there a statistical equality between the materials studied . We conclude that the resins studied change in color and resin enamel G III was the most suffered major color changes after aging by thermocycling .

Ciclamato de sódio em refrigerantes de baixa caloria

Sodium cyclamate contents in the widely consumed low calorie soft drinks were determined. Low calorie soft drinks made from cola, guarana, orange, lemon and grape were analyzed following the technique described by Sjörberg and Alanko (1987), with some modifications. The methodology recovery assays were carried out at three spiked levels, and the average recovery of 92.5% and 110.3% were found in cola and guarana, respectively; and the relative standard deviation was of 3.7%. The average sodium cyclamate contents ranged from 27.1 ± 1.1 (cola A) to 127.3 ± 1.5 mg.100 mL-1 (lemon B), indicating that the acceptable daily intake of the sweetener can be easily exceeded after drinking low calorie beverages. All of the analyzed low calorie soft drinks showed sodium cyclamate contents higher than those stated on the label, ranging from 12.9% (cola A) to 19.0% (lemon B). Among 18 low calorie soft drinks analyzed, only four showed the average sodium cyclamate contents in accordance with the maximum limit permitted by Brazilian legislation, that is 40 mg.100 mL-1 of beverage; and in other samples the sweetener exceeded ranging from 74.8% (orange) to 218.3% (lemon B) above of the limit permitted.