Centro Universitario Central Paulista

São Carlos, Brazil

Centro Universitario Central Paulista

São Carlos, Brazil
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Zeraik M.L.,University of Sao Paulo | Pereira C.A.M.,Centro Universitario Central Paulista | Zuin V.G.,Federal University of São Carlos | Yariwake J.H.,University of Sao Paulo
Brazilian Journal of Pharmacognosy | Year: 2010

This paper consists of a bibliographic review of the most relevant edible Brazilian Passiflora species (Passiflora edulis fo. flavicarpa O. Deg., P. alata Curtis and P. edulis fo. edulis). Most of the reports in the literature focus solely on Passiflora leaves, whereas this review contains information about passion fruit pulp, rind and seeds, highlightening chemical composition, nutritional and pharmacological studies. The emphasis on the maracujá fruit is due to the extensive consumption of passion fruit juice (fresh or processed) in Brazil and on ongoing investigations into its potential as a functional food.

Dantas N.O.,Federal University of Minas Gerais | Silva A.D.S.,Federal University of Minas Gerais | Ayta W.E.F.,Federal University of Minas Gerais | Silva S.W.D.,University of Brasilia | And 4 more authors.
Chemical Physics Letters | Year: 2012

Zn 1-xMn xTe dilute magnetic nanocrystals (NCs) were synthesized by fusion method in a glass template and annealed post-growth. Magnetism and quantum confinement of incorporated Mn-ions were confirmed by magnetic force microscopy (MFM), Raman scattering (RS) and electron paramagnetic resonance (EPR). A blueshift in the RS spectra were clear signatures of Mn 2+ incorporation in the dot structure which were monitored as a function of increasing doping concentration, x. MFM images strongly indicated the formation of Zn 1-xMn xTe magnetic phases in the glass system. The EPR spectra showed six lines associated to the S = 5/2 spin half filled d-state, characteristic of Mn 2+ ions. © 2012 Elsevier B.V. All rights reserved.

Neto E.S.F.,Federal University of Uberlandia | Da Silva S.W.,University of Brasilia | Morais P.C.,University of Brasilia | Vasilevskiy M.I.,University of Minho | And 3 more authors.
Journal of Raman Spectroscopy | Year: 2011

Optical phonon modes, confined in CdS xSe 1-x nanocrystal (NC) quantum dots (≈2 nm in radius) grown in a glass matrix by the melting-nucleation method, were studied by resonant Raman scattering (RRS) spectroscopy and theoretical modeling. The formation of nanocrystalline quantum dots (QDs) is evidenced by the observation of absorption peaks and theoretically expected resonance bands in the RRS excitation spectra. This system, a ternary alloy, offers the possibility to investigate the interplay between the effects of phonon localization by disorder and phonon confinement by the NC/matrix interface. Based on the concept of propagating optical phonons, which is accepted for two-mode pseudo-binary alloys in their bulk form, we extended the continuous lattice dynamics model, which has successfully been used for nearly spherical NCs of binary materials, to the present case. After determining the alloy composition for NCs (that was evaluated with only 2-3% uncertainty using the bulk longitudinal optical phonon wavenumbers) and the NC size (using atomic force microscopy and optical absorption data), the experimental RRS spectra were described rather well by this theory, including the line shape and polarization dependence of the scattering intensity. Even though the presence of a compressive strain in the NCs (introduced by the matrix) masks the expected downward shift owing to the phonons' spatial quantization, the asymmetric broadening of both Raman peaks is similar to that characteristic of NCs of pure binary materials. Although with some caution, we suggest that both CdSe-like and CdS-like optical phonon modes indeed are propagating within the NC size unless the alloy is considerably heterogeneous. Copyright © 2011 John Wiley & Sons, Ltd.

Ferri F.A.,University of Sao Paulo | Pereira-Da-Silva M.A.,University of Sao Paulo | Pereira-Da-Silva M.A.,Centro Universitario Central Paulista | Zanatta A.R.,University of Sao Paulo
Materials Chemistry and Physics | Year: 2011

Thin films of Si with Mn concentrations up to 20 at.% were prepared by conventional radio frequency sputtering. After deposition, the films were submitted to thermal annealing treatments and their properties were investigated by composition analysis, Raman scattering, microscopic techniques, optical transmission, and electrical transport. The experimental results show that all as-deposited films are amorphous, with the Mn atoms being effective and controllably incorporated into the Si matrix. Moreover, thermal annealing at increasing temperatures induces the crystallization of the films as well as the growth of the MnSi 1.7 silicide phase in the Mn-containing samples. Along with sample crystallization, some films become covered by small structures that are randomly distributed all over their surfaces. These structures are essentially Mn-containing Si crystals with typical sizes in the (sub-) micrometer range and, as the thermal annealing advances, the density of structures increases at the expense of their individual average dimension. The development and characteristics of the observed superficial structures are discussed in view of the main structural and morphological properties of the samples. © 2011 Elsevier B.V.

Tonoli G.H.D.,Federal University of Lavras | Teixeira E.M.,Laboratorio Nacional Of Nanotecnologia Para O Agronegocio Lnna | Correa A.C.,Laboratorio Nacional Of Nanotecnologia Para O Agronegocio Lnna | Marconcini J.M.,Laboratorio Nacional Of Nanotecnologia Para O Agronegocio Lnna | And 4 more authors.
Carbohydrate Polymers | Year: 2012

There is growing interest in cellulose nanofibres from renewable sources for several industrial applications. However, there is a lack of information about one of the most abundant cellulose pulps: bleached Eucalyptus kraft pulp. The objective of the present work was to obtain Eucalyptus cellulose micro/nanofibres by three different processes, namely: refining, sonication and acid hydrolysis of the cellulose pulp. The refining was limited by the low efficiency of isolated nanofibrils, while sonication was more effective for this purpose. However, the latter process occurred at the expense of considerable damage to the cellulose structure. The whiskers obtained by acid hydrolysis resulted in nanostructures with lower diameter and length, and high crystallinity. Increasing hydrolysis reaction time led to narrower and shorter whiskers, but increased the crystallinity index. The present work contributes to the different widespread methods used for the production of micro/nanofibres for different applications. © 2012 Elsevier Ltd. All rights reserved.

Ferri F.A.,University of Sao Paulo | Pereira-Da-Silva M.A.,University of Sao Paulo | Pereira-Da-Silva M.A.,Centro Universitario Central Paulista
Materials Chemistry and Physics | Year: 2012

This study investigated the composition, structure and optical properties of amorphous SiCo and GeCo films. The samples were prepared by radio frequency sputtering. Films were deposited with Co atomic concentrations in the range of 1.7-10.3 at.%. After deposition, the films were submitted to thermal treatments up to 900°C and investigated by energy dispersive X-ray spectrometry, X-ray diffraction, Raman scattering and optical transmission spectroscopy. Additionally, magnetic force microscopy measurements were performed at room temperature. For comparison purposes, Co-free samples were also prepared, annealed and characterized following a similar procedure. The experimental results indicated the following: (1) the Co atoms were effectively and homogeneously incorporated into the amorphous hosts; (2) the as-deposited films (either pure or containing Co) were essentially amorphous; (3) annealing the films at high temperatures induced crystallization; (4) after crystallization, non-magnetic CoSi 2 (silicide) and CoGe 2 (germanide) phases were identified in the Co-containing Si and Ge films, respectively; (5) the optical properties of the films were significantly affected by the insertion of Co and by the annealing temperature; and (6) the samples exhibited a reduced magnetic signal at room temperature. These experimental observations were systematically studied, which are presented and discussed in this report. © 2012 Elsevier B.V. All rights reserved.

Ribeiro R.,University of Sao Paulo | de Nardi I.R.,Centro Universitario Central Paulista | Fernandes B.S.,University of Sao Paulo | Foresti E.,University of Sao Paulo | Zaiat M.,University of Sao Paulo
Biodegradation | Year: 2013

Because benzene, toluene, ethylbenzene, and xylenes (BTEX) and ethanol are important contaminants present in Brazilian gasoline, it is essential to develop technology that can be used in the bioremediation of gasoline-contaminated aquifers. This paper evaluates the performance of a horizontal-flow anaerobic immobilized biomass (HAIB) reactor fed with water containing gasoline constituents under denitrifying conditions. Two HAIB reactors filled with polyurethane foam matrices (5 mm cubes, 23 kg/m3 density and 95 % porosity) for biomass attachment were assayed. The reactor fed with synthetic substrate containing protein, carbohydrates, sodium bicarbonate and BTEX solution in ethanol, at an Hydraulic retention time (HRT) of 13. 5 h, presented hydrocarbon removal efficiencies of 99 % at the following initial concentrations: benzene 6. 7 mg/L, toluene 4. 9 mg/L, m-xylene and p-xylene 7. 2 mg/L, ethylbenzene 3. 7 mg/L, and nitrate 60 mg N/L. The HAIB reactor fed with gasoline-contaminated water at an HRT of 20 h showed hydrocarbon removal efficiencies of 96 % at the following initial concentrations: benzene, 4. 9 mg/L; toluene, 7. 2 mg/L; m-xylene, 3. 7 mg/L; and nitrate 400 mg N/L. Microbiological observations along the length of the HAIB reactor fed with gasoline-contaminated water confirmed that in the first segment of the reactor, denitrifying metabolism predominated, whereas from the first sampling port on, the metabolism observed was predominantly methanogenic. © 2012 Springer Science+Business Media B.V.

Neto E.S.F.,Federal University of Uberlandia | Dantas N.O.,Federal University of Uberlandia | Da Silva S.W.,University of Brasilia | Morais P.C.,University of Brasilia | And 2 more authors.
Journal of Raman Spectroscopy | Year: 2010

This work gives the evidence of the lattice contraction in CdSe nanocrystals (NCs) grown in a glass matrix. The CdSe NCs were investigated by atomic force microscopy (AFM), optical absorption (OA), and Raman spectroscopy. The average size of CdSe NCs can be estimated by AFM images. Using the OA spectra and the effective-mass approximation, it was also possible to estimate the average sizes of CdSe NCs, which agree very well with the AFM data. These results showed that the CdSe NCs grow with increasing time of heat treatment. The blue shift of the longitudinal optical (LO) modes and surface optical (SO) phonon modes with an increase in the average radius of the NCs, shown in the Raman spectra, was explained by the lattice contraction in CdSe NCs caused by thermodynamic interactions at the interface with the host glass matrix. Copyright © 2010 John Wiley & Sons, Ltd.

Gross M.A.,University of Brasilia | Sales M.J.A.,University of Brasilia | Soler M.A.G.,University of Brasilia | Pereira-Da-Silva M.A.,University of Sao Paulo | And 3 more authors.
RSC Advances | Year: 2014

Graphene oxide (GO) multilayers were produced by the layer-by-layer technique after successive immersions of quartz slides into aqueous suspensions of cationic poly(diallyldimethyl ammonium chloride) (PDAC) and anionic GO. The adsorbed amount of GO within the multilayers measured ex situ by UV-vis spectroscopy was found to increase linearly with the number of PDAC-GO bilayers. UV-vis and Raman spectra confirmed the conversion of GO to its reduced form, namely reduced graphene oxide (RGO), when the multilayers were subjected to hot hydrazine. According to AFM images, multilayers are flat with GO sheets forming edge structures. Additionally, impedance spectroscopy provided information regarding the multilayer growth mechanism, which starts with isolated GO sheets that bridge each other after deposition of five PDAC-GO bilayers. As a proof of principle, it was demonstrated that a sensor array composed by reduced multilayers deposited onto interdigitated microelectrodes and interrogated by impedance spectroscopy is capable of discriminating vapours of volatile solvents, including toluene, gasoline, ethanol, chloroform, and acetone, as well as chemicals in aqueous solutions, such as hydrochloric acid, sodium chloride, ammonium hydroxide, and sucrose. This capability was made possible only because the LbL assembly permitted one to tune the sensors' sensitivity with the number of PDAC-GO bilayers. The results presented herein suggest that the reduced PDAC-GO multilayers are promising elements for non-specific chemical sensors. This journal is © the Partner Organisations 2014.

De Nardi I.R.,Centro Universitario Central Paulista | Del Nery V.,Ceu Azul Alimentos Ltda | Amorim A.K.B.,University of Brasilia | dos Santos N.G.,Centro Universitario Central Paulista | Chimenes F.,Centro Universitario Central Paulista
Desalination | Year: 2011

Since the poultry slaughter industry is highly water-consuming and wastewater generator, it is essential to take a step towards achieving the sustainability of wastewater reclamation and reuse schemes. This paper evaluates the performance of a lab-scale advanced wastewater treatment system that consists of sequencing batch reactor (SBR), chemical-dissolved-air flotation (DAF) system and ultraviolet (UV) disinfection, used for the reclamation from anaerobically pre-treated poultry slaughterhouse wastewater. Twelve-hour cycles in a fill-aerobic-anoxic-settle-discharge sequence and ethanol addition as carbon source for denitrification at 1.41±0.19C/N ratio were the SBR operating conditions for nitrogen removal. Ferric chloride and cationic polymer as flocculant aid were the chemicals used for phosphorus removal. 4.5-5.5 coagulation pH, 1.32±0.19 Fe/P molar ratio associated with 1.0mgL-1 cationic polymer, 20% recycle rate and 10cmmin-1 flotation velocity were the best chemical-DAF system operating conditions from which resulted >99% phosphorus and 65±25% suspended solids removals. UV radiation dosages ranging from 23 to 32mWscm-2 have effectively inactivated the coliform organisms and Salmonella. Under such operating conditions, organic matter, nutrients, suspended solids and indicator organisms in the final effluent met the quality standards of the legislation for both potable water and effluent discharge to the receiving waters. Zero discharge potentials for the sustainability of the poultry slaughter industry were also explored. The use of all the reclaimed water in closed circuit is expected to reduce the well water input by 60% with no treated effluent discharge to the river during this stage. The use of reclaimed water in semiclosed circuit is expected to reduce the well water input by 46% and the treated effluent discharge to the river by 76%. © 2010 Elsevier B.V.

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