Physical, Thermal and Water-Sorption Properties of Passion Fruit Seeds

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

Processamento do alho negro

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Adsorção de antibióticos em meio aquoso utilizando diferentes adsorventes

Pós-graduação em Ciência dos Materiais - FEIS

Desidratação de polpa de manga em leito de espuma com e sem intermitência térmica

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

Extração e caracterização de amido de quinoa, cañihua e Mirabilis jalapa

Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE

Improvement of water transport and carotenoid retention during drying of papaya by applying ultrasonic osmotic pretreatment

The effect of ultrasound and osmotic dehydration pretreatments on papaya drying kinetics was investigated. The ultrasound pretreatment was carried out in an ultrasonic bath at 30 A degrees C. The osmotic pretreatment in sucrose solution was carried out in an incubator at 34 A degrees C and agitation of 80 rpm for 210 min. The drying process was conducted in a fixed bed dryer at 70 A degrees C. Experimental data were fitted successfully using the Page model for dried fresh and pretreated fruits, with coefficient of determination greater than 0.9992 and average relative error lower that 14.4 %. The diffusional model was used to describe the moisture transfer, and the effective water diffusivity was identified in the order of 10(-9) m(2) s(-1). It was found that drying rates of osmosed fruits were the lowest due to the presence of infused solutes, while the ultrasound pretreatment contributed to faster drying rates. Evaluation of the dried fruit was performed by means of total carotenoids retention. Ultrasound treatments in distilled water prior to air-drying gave rise to dried papayas with retention of carotenoids in the range 30.4-39.8 % and the ultrasonic-assisted osmotic dehydration of papayas showed carotenoids retention values up to 64.9 %, whereas the dried fruit without pretreatment showed carotenoids retention lower than 24 %.

Estudo da adsorção de níquel (II) e zinco (II) em soluções aquosas por lama vermelha natural e ativada: influência do PH, isotermas, cinética e termodinâmica

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

Adsorção de metais em solução aquosa pelos processos de batelada e coluna de leito fixo utilizando silsesquioxano funcionalizado com 5-amino-1,3,4-tiadiazol-2-tiol

Pós-graduação em Ciência dos Materiais - FEIS

Imagem de tensor de difusão na epilesia de lobo temporal mesial

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

Submesoscale activity over the Argentinian shelf

Submesoscale activity over the Argentinian shelf is investigated by means of high resolution primitive equation numerical solutions. These reveal energetic turbulent activity (visually similar to the one occasionally seen in satellite images) at scales O(5 km) in fall and winter that is linked to mixed layer baroclinic instability. The air-sea heat flux responsible for (i) deepening the upper ocean boundary layer (at these seasons) and (ii) maintaining a cross-shelf background density gradient is the key environmental parameter controlling submesoscale activity. Implications of submesoscale turbulence are investigated. Its mixing efficiency estimated by computing a diffusivity coefficient is above 30 m(2) s(-1) away from the shallowest regions. Aggregation of surface buoyant material by submesoscale currents occurs within hours and is presumably important to the ecosystem.

Optical and thermal investigation of GeO2-PbO thin films doped with Au and Ag nanoparticles

The present work reports on the thermo-optical study of germanate thin films doped with Au and Ag nanoparticles. Transmission Electron Microscopy images, UV-visible absorption and Micro-Raman scattering evidenced the presence of nanoparticles and the formation of collective excitations, the so called surface plasmons. Moreover, the effects of the metallic nanoparticles in the thermal properties of the films were observed. The thermal lens technique was proposed to evaluate the Thermal Diffusivity (D) of the samples. It furnishes superficial spatial resolution of about 100 mu m, so it is appropriate to study inhomogeneous samples. It is shown that D may change up to a factor 3 over the surface of a film because of the differences in the nanoparticles concentration distribution. (C) 2011 Elsevier B.V. All rights reserved.

Straightforward Synthesis of Carbon-Supported Ag Nanoparticles and Their Application for the Oxygen Reduction Reaction

In this paper we report a simple and environmentally friendly synthesis of silver nanoparticles (AgNps) and their activities towards the oxygen reduction reaction (ORR). Ultraviolet spectroscopy (UV-vis) and transmission electron microscopy confirmed the formation of poly(vinyl pyrrolidone)-protected colloidal AgNps through direct reduction of Ag+ by glycerol in alkaline medium at room temperature. For the ORR tests, the AgNps were directly produced onto carbon to yield the Ag/C catalyst. Levich plots revealed the process to occur via 2.7 electrons, suggesting that the carbon support contributes to the ORR. We discuss here possibilities of improving the catalytic properties of the Ag/C for ORR by optimizing the parameters of the synthesis.

DTI voxelwise analysis did not differentiate older depressed patients from older subjects without depression

Introduction: Neuroimaging has been widely used in studies to investigate depression in the elderly because it is a noninvasive technique, and it allows the detection of structural and functional brain alterations. Fractional anisotropy (FA) and mean diffusivity (MD) are neuroimaging indexes of the microstructural integrity of white matter, which are measured using diffusion tensor imaging (DTI). The aim of this study was to investigate differences in FA or MD in the entire brain without a previously determined region of interest (ROI) between depressed and non-depressed elderly patients. Method: Brain magnetic resonance imaging scans were obtained from 47 depressed elderly patients, diagnosed according to DSM-IV criteria, and 36 healthy elderly patients as controls. Voxelwise statistical analysis of FA data was performed using tract-based spatial statistics (TBSS). Results: After controlling for age, no significant differences among FA and MD parameters were observed in the depressed elderly patients. No significant correlations were found between cognitive performance and FA or MD parameters. Conclusion: There were no significant differences among FA or MD values between mildly or moderately depressed and non-depressed elderly patients when the brain was analyzed without a previously determined ROI. (C) 2012 Elsevier Ltd. All rights reserved.

THE ROLE OF TURBULENT MAGNETIC RECONNECTION IN THE FORMATION OF ROTATIONALLY SUPPORTED PROTOSTELLAR DISKS

The formation of protostellar disks out of molecular cloud cores is still not fully understood. Under ideal MHD conditions, the removal of angular momentum from the disk progenitor by the typically embedded magnetic field may prevent the formation of a rotationally supported disk during the main protostellar accretion phase of low-mass stars. This has been known as the magnetic braking problem and the most investigated mechanism to alleviate this problem and help remove the excess of magnetic flux during the star formation process, the so-called ambipolar diffusion (AD), has been shown to be not sufficient to weaken the magnetic braking at least at this stage of the disk formation. In this work, motivated by recent progress in the understanding of magnetic reconnection in turbulent environments, we appeal to the diffusion of magnetic field mediated by magnetic reconnection as an alternative mechanism for removing magnetic flux. We investigate numerically this mechanism during the later phases of the protostellar disk formation and show its high efficiency. By means of fully three-dimensional MHD simulations, we show that the diffusivity arising from turbulent magnetic reconnection is able to transport magnetic flux to the outskirts of the disk progenitor at timescales compatible with the collapse, allowing the formation of a rotationally supported disk around the protostar of dimensions similar to 100 AU, with a nearly Keplerian profile in the early accretion phase. Since MHD turbulence is expected to be present in protostellar disks, this is a natural mechanism for removing magnetic flux excess and allowing the formation of these disks. This mechanism dismisses the necessity of postulating a hypothetical increase of the ohmic resistivity as discussed in the literature. Together with our earlier work which showed that magnetic flux removal from molecular cloud cores is very efficient, this work calls for reconsidering the relative role of AD in the processes of star and planet formation.

Heat conduction in a chain of harmonic and anharmonic oscillators under the presence of an energy conserving noise

Reproducing Fourier's law of heat conduction from a microscopic stochastic model is a long standing challenge in statistical physics. As was shown by Rieder, Lebowitz and Lieb many years ago, a chain of harmonically coupled oscillators connected to two heat baths at different temperatures does not reproduce the diffusive behaviour of Fourier's law, but instead a ballistic one with an infinite thermal conductivity. Since then, there has been a substantial effort from the scientific community in identifying the key mechanism necessary to reproduce such diffusivity, which usually revolved around anharmonicity and the effect of impurities. Recently, it was shown by Dhar, Venkateshan and Lebowitz that Fourier's law can be recovered by introducing an energy conserving noise, whose role is to simulate the elastic collisions between the atoms and other microscopic degrees of freedom, which one would expect to be present in a real solid. For a one-dimensional chain this is accomplished numerically by randomly flipping - under the framework of a Poisson process with a variable “rate of collisions" - the sign of the velocity of an oscillator. In this poster we present Langevin simulations of a one-dimensional chain of oscillators coupled to two heat baths at different temperatures. We consider both harmonic and anharmonic (quartic) interactions, which are studied with and without the energy conserving noise. With these results we are able to map in detail how the heat conductivity k is influenced by both anharmonicity and the energy conserving noise. We also present a detailed analysis of the behaviour of k as a function of the size of the system and the rate of collisions, which includes a finite-size scaling method that enables us to extract the relevant critical exponents. Finally, we show that for harmonic chains, k is independent of temperature, both with and without the noise. Conversely, for anharmonic chains we find that k increases roughly linearly with the temperature of a given reservoir, while keeping the temperature difference fixed.