Características estruturais de géis de sílica preaparados a partir da sonohidrólise do tetraetilortosilicato com adições de álcool polivinílico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Modelling an expert GIS system based on knowledge to evaluate oil spill environmental sensitivity

Oil spills cause great damage to coastal habitats, especially when rapid and suitable response measures are not taken. Establishing high priority areas is fundamental for the operation of response teams. Under this context and considering the need for keeping all geographical information up-to-date for emergencial use, the present study proposes employing a decision tree coupled with a knowledge-based approach using GIS to assign oil sensitivity indices to Brazilian coastal habitats. The modelled system works based on rules set by the official standards of Brazilian Federal Environment Organ. We tested it on one of the littoral regions of Brazil where transportation of petroleum is most intense: the coast of the municipalities of Sao Sebastiao and Caraguatatuba in the northern littoral of São Paulo state, Brazil. The system automatically ranked the littoral sensitivity index of the study area habitats according to geographical conditions during summer and winter; since index ranks of some habitats varied between these seasons because of sediment alterations. The obtained results illustrate the great potential of the proposed system in generating ESI maps and in aiding response teams during emergency operations. (C) 2009 Elsevier Ltd. All rights reserved.

Photoluminescence properties of PZT 52/48 synthesized by microwave hydrothermal method using PVA with template

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

Biodegradation of blend films PVA/PVC, PVA/PCL in soil and soil with landfill leachate

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

A study of habitat fragmentation in Southeastern Brazil using remote sensing and geographic information systems (GIS)

The purpose of this work was to study fragmentation of forest formations (mesophytic forest, riparian woodland and savannah vegetation (cerrado)) in a 15,774-ha study area located in the Municipal District of Botucatu in Southeastern Brazil (São Paulo State). A land use and land cover map was made from a color composition of a Landsat-5 thematic mapper (TM) image. The edge effect caused by habitat fragmentation was assessed by overlaying, on a geographic information system (GIS), the land use and land cover data with the spectral ratio. The degree of habitat fragmentation was analyzed by deriving: 1. mean patch area and perimeter; 2. patch number and density; 3. perimeter-area ratio, fractal dimension (D), and shape diversity index (SI); and 4. distance between patches and dispersion index (R). In addition, the following relationships were modeled: 1. distribution of natural vegetation patch sizes; 2. perimeter-area relationship and the number and area of natural vegetation patches; 3. edge effect caused by habitat fragmentation, the values of R indicated that savannah patches (R = 0.86) were aggregated while patches of natural vegetation as a whole (R = 1.02) were randomly dispersed in the landscape. There was a high frequency of small patches in the landscape whereas large patches were rare. In the perimeter-area relationship, there was no sign of scale distinction in the patch shapes, In the patch number-landscape area relationship, D, though apparently scale-dependent, tends to be constant as area increases. This phenomenon was correlated with the tendency to reach a constant density as the working scale was increased, on the edge effect analysis, the edge-center distance was properly estimated by a model in which the edge-center distance was considered a function of the to;al patch area and the SI. (C) 1997 Elsevier B.V. B.V.

Applying GIS tools for analysing urban thermal environment

A methodology for analyzing the solar access and its influence on both air temperature and thermal comfort of the urban environment was here developed by applying the potentiality of GIS tools. Urban canyons in a specific area of a Brazilian medium sized city were studied. First, a computational algorithm was applied in order to allow the determination of sky view factors (SVF) and sun-paths in urban canyons. Then, air temperatures in 40 measurement points were collected within the study area. Solar radiation values of these canyons were determined and subsequently stored in a GIS database. The creation of thermal maps for the whole neighbourhood was possible due to a statistical treatment of the data, by promoting the interpolation of values. All data could then be spatially cross-examined. In addition, thermal comfort maps for summer and winter periods were generated. The methodology allowed the identification of thermal tendencies within the neighbourhood, what can be useful in the conception of guidelines for urban planning purposes.

Cisalhamento na Linha de Cola de Compensados de Eucalyptus sp. e Adesivo PVA

Studies on new adhesives and resins for bonding wood and wood products are being carried out with the intention to improve their properties, taking into account a lower environmental impact. To this end, new formulations of polyvinyl acetate (PVA) adhesives have been developed, because they have no polluting harmful to health chemicals in their composition, in contrast to formaldehyde-based resins; which in turn are the most commonly used for wood panels production these days. This study tested three different formulations of PVA adhesives, with different pressing times and temperatures for the production of Eucalyptus sp. plywood, obtaining satisfactory results with respect to shear strength at the bondline, which was higher for the PVA adhesives compared to the urea-formaldehyde and phenol-formaldehyde panels found in the literature.

Bionanocomposites from electrospun PVA/pineapple nanofibers/Stryphnodendron adstringens bark extract for medical applications

Tissue engineering has been defined as an interdisciplinary field that applies the principles of engineering and life sciences for the development of biological substitutes to restore, maintain or improve tissue function. This area is always looking for new classes of degradable biopolymers that are biocompatible and whose activities are controllable and specific, more likely to be used as cell scaffolds, or in vitro tissue reconstruction. In this paper, we developed a novel bionanocomposite with homogeneous porous distribution and prospective natural antimicrobial properties by electrospinning technique using Stryphodedron barbatimao extract (Barbatimão). SEM images showed equally distribution of nanofibres. DSC and TGA showed higher thermal properties and change crystallinity of the developed bionanocomposite mainly because these structural modification. © 2012 Elsevier B.V.

Enzymatic transesterification of soybean oil with ethanol using lipases immobilized on highly crystalline PVA microspheres

Polyvinyl alcohol (PVA) microspheres with different degree of crystallinity were used as solid supports for Rhizomucor miehei lipase immobilization, and the enzyme-PVA complexes were used as biocatalysts for the transesterification of soybean oil to fatty acid ethyl esters (FAEE). The amounts of immobilized enzyme on the polymeric supports were similar for both the amorphous microspheres (PVA4) and the high crystalline microspheres (PVA25). However, the enzymatic activity of the immobilized enzymes was depended on the crystallinity degree of the PVA microspheres: enzymes immobilized on the PVA4 microspheres have shown low enzymatic activity (6.13 U mg-1), in comparison with enzymes immobilized on the high crystalline PVA25 microspheres (149.15 U mg-1). A synergistic effect was observed for the enzyme-PVA25 complex during the transesterification reaction of soybean oil to FAEE: transesterification reactions with free enzyme with the equivalent amount of enzyme that were immobilized onto the PVA25 microspheres (5.4 U) have yielded only 20% of FAEE, reactions with the pure highly crystalline microsphere PVA25 have not yielded FAEE, however reactions with the enzyme-PVA25 complexes have yielded 66.3% of FAEE. This synergistic effect of an immobilized enzyme on a polymeric support has not been observed before for transesterification reaction of triacylglycerides into FAEE. Based on ATR-FTIR, 23Na- and 13C-NMR-MAS spectroscopic data and the interaction of the polymeric network intermolecular hydrogen bonds with the lipases residual amino acids a possible explanation for this synergistic effect is provided. © 2013 Elsevier Ltd. All rights reserved.

Influência da adição de surfactantes a géis clareadores à base de peróxido de hidrogênio a 35% e peróxido de carbamida a 10% na efetividade do clareamento dental: estudo in vitro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Obtenção de nanofibras de curauá e aplicação como reforço em compósitos baseados em PVA

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

Estudo reológico de sistemas gelatina/colágeno/amido para obtenção de géis e aplicação dietéticas de gelatina

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comportamento reológico de géis de amido de mandioquinha salsa (Arracacia xanthorrhiza B.)

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