TiO2/PDMS nanocomposites for use on self-cleaning surfaces

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of solvent on the morphology and photocatalytic properties of ZnS decorated CeO2 nanoparticles

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Leaf-litter decomposition of the mangrove species Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle

This study evaluated the decomposition process of leaf litter from the main Brazilian mangrove species Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle. Senescent leaves were collected, dried and placed in nylon bags with different mesh sizes (fine: 2x2mm and coarse: 8x8mm). The bags were distributed over the sediment, and replicates of each species and mesh size were collected periodically over 4months. In the laboratory, the dry weight of the samples was measured, and the decomposition coefficient (k) for each species and mesh size was obtained over time. All species showed a rapid decomposition rate at the beginning of the experiment, followed by a slower but steady rate of decomposition over time. The rate of leaf litter decomposition was highest in A. schaueriana, intermediate in L. racemosa and lowest in R. mangle. The difference was mainly linked to the activity and abundance of detritivores, together with the different litter quality of the species, which determined their palatability and probably influenced the decomposition process.

Study of some volatile compounds evolved from the thermal decomposition of atenolol

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

Singular Value Decomposition and Ligand Binding Analysis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaluation of Decomposition Kinetics of Poly (Ether-Ether-Ketone) by Thermogravimetric Analysis

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

Structure and photocatalytic properties of Nb-doped Bi12TiO20 prepared by the oxidant peroxide method (OPM)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Titanate nanotubes produced from microwave-assisted hydrothermal synthesis: Photocatalytic and structural properties

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Martensite decomposition in Cu-Al-Mn-Ag alloys

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

Evaluation of Decomposition Procedure to Determine Ba, Co, Cr, Cu, Ni, Mn, V, and Zn Total Content in Soil Samples

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Model updating of the non-linear vibrating structures through Volterra series and proper orthogonal decomposition

Classical procedures for model updating in non-linear mechanical systems based on vibration data can fail because the common linear metrics are not sensitive for non-linear behavior caused by gaps, backlash, bolts, joints, materials, etc. Several strategies were proposed in the literature in order to allow a correct representative model of non-linear structures. The present paper evaluates the performance of two approaches based on different objective functions. The first one is a time domain methodology based on the proper orthogonal decomposition constructed from the output time histories. The second approach uses objective functions with multiples convolutions described by the first and second order discrete-time Volterra kernels. In order to discuss the results, a benchmark of a clamped-clamped beam with an pre-applied static load is simulated and updated using proper orthogonal decomposition and Volterra Series. The comparisons and discussions of the results show the practical applicability and drawbacks of both approaches.

Investigação das propriedades fotocatalíticas de filmes finos de TiO2 depositados por solução orgânica de citratos

Nowadays environmental pollution can be identified as a major problem in developed and developing countries. This is the result of several factors, such as inappropriate use of natural resources, inficiente legislation and not ecological awareness. Moreover, many other procedures as incorrect use of chemicals still contributed to the worsening of the problem. In this work, we develop a working with the environmental ideals, aiming to contribute to the decomposition of organic material through decomposition of rhodamine in TiO2 thin films on a silicon substrate. The degradation performance was monitored with the aid of techniques such as atomic force microscopy, transmission electron microscopy, field emission gun scanning electron microscopy, Fourier transform spectroscopy, thermal and photocatalytic analyses

Long-range and short-range structures of cube-like shape SrTiO3 powders: microwave-assisted hydrothermal synthesis and photocatalytic activity

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Thermal study in solid state of Zn(II)-diclofenac complex: Behavior kinetic of dehydration, transition phase and thermal decomposition

The dehydration, thermal decomposition and transition phase stage of Zn(II)-diclofenac compoundwere studied by simultaneous TG-DTA and DSC techniques. The TG and DSC curves of this compoundwere obtained with the mass of sample of 2 and 5 mg. Additionally, DSC curves were carried out inopened and closed a-alumina pans under static and nitrogen atmosphere. The DTA and DSC curves showthat this compound possesses exothermic transition phase between 170-180 ºC, which it is irreversible(monotropic reaction). The kinetics study of this transition phase stage was evaluated by DSC undernon-isothermal conditions. The obtained data were evaluated with the isoconversional method, where thevalues of activation energy (Ea/kJmol-1) was plotted in function of the conversion degree (a). The resultsshow that due to mass sample, different activation energies were obtained. From these curves a tendencycan be seen where the plots maintain the same profile for closed lids and almost run parallel to each other.

Effect of the iron doping on the thermal decomposition of the polymeric precursor for the titanium dioxide powder synthesis

The Polymeric Precursor Method has proved suitable for synthesizing reactive powders using low temperatures of calcination, especially when compared with conventional methods. However, during the thermal decomposition of the polymeric precursor the combustion event can be releases an additional heat that raises the temperature of the sample in several tens of degrees Celsius above the set temperature of the oven. This event may be detrimental to some material types, such as the titanium dioxide semiconductor. This ceramic material has a phase transition at around 600 ° C, which involves the irreversible structural rearrangement, characterized by the phase transition from anatase to rutile TiO2 phase. The control of the calcination step then becomes very important because the efficiency of the photocatalyst is dependent on the amount of anatase phase in the material. Furthermore, use of dopant in the material aims to improve various properties, such as increasing the absorption of radiation and in the time of the excited state, shifting of the absorption edge to the visible region, and increasing of the thermal stability of anatase. In this work, samples of titanium dioxide were synthesized by the Polymeric Precursor Method in order to investigate the effect of Fe (III) doping on the calcination stages. Thermal analysis has demonstrated that the Fe (III) insertion at 1 mol% anticipates the organic decomposition, reducing the combustion event in the final calcination. Furthermore, FTIR-PAS, XRD and SEM results showed that organic matter amount was reduced in the Fe (III)-doped TiO2 sample, which reduced the rutile phase amount and increased the reactivity and crystallinity of the powder samples.